tty: serial: fsl_lpuart: avoid idle preamble pending if CTS is enabled

If the remote uart device is not connected or not enabled after booting
up, the CTS line is high by default. At this time, if we enable the flow
control when opening the device(for example, using “stty -F /dev/ttyLP4
crtscts” command), there will be a pending idle preamble(first writing 0
and then writing 1 to UARTCTRL_TE will queue an idle preamble) that
cannot be sent out, resulting in the uart port fail to close(waiting for
TX empty), so the user space stty will have to wait for a long time or
forever.

This is an LPUART IP bug(idle preamble has higher priority than CTS),
here add a workaround patch to enable TX CTS after enabling UARTCTRL_TE,
so that the idle preamble does not get stuck due to CTS is deasserted.

Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Link: https://lore.kernel.org/r/20240305015706.1050769-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231110152927.70601-17-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Use port lock wrappers

When a serial port is used for kernel console output, then all
modifications to the UART registers which are done from other contexts,
e.g. getty, termios, are interference points for the kernel console.

So far this has been ignored and the printk output is based on the
principle of hope. The rework of the console infrastructure which aims to
support threaded and atomic consoles, requires to mark sections which
modify the UART registers as unsafe. This allows the atomic write function
to make informed decisions and eventually to restore operational state. It
also allows to prevent the regular UART code from modifying UART registers
while printk output is in progress.

All modifications of UART registers are guarded by the UART port lock,
which provides an obvious synchronization point with the console
infrastructure.

To avoid adding this functionality to all UART drivers, wrap the
spin_[un]lock*() invocations for uart_port::lock into helper functions
which just contain the spin_[un]lock*() invocations for now. In a
subsequent step these helpers will gain the console synchronization
mechanisms.

Converted with coccinelle. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20230914183831.587273-28-john.ogness@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Use devm_platform_get_and_ioremap_resource()

Convert platform_get_resource(), devm_ioremap_resource() to a single
call to devm_platform_get_and_ioremap_resource(), as this is exactly
what this function does.

Signed-off-by: Yangtao Li <frank.li@vivo.com>
Link: https://lore.kernel.org/r/20230712062853.11007-7-frank.li@vivo.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: add IDLE interrupt support for rx_dma on imx7ulp/imx8ulp/imx8qxp

Add IDLE interrupt support for receive dma on imx7ulp/imx8ulp/imx8qxp
platforms to replace the receive dma timer function, because the receive
dma timer has bigger latency than idle interrupt triggering, which may
cause the Bluetooth Firmware download timeout on Android platform(it
has a limited FW download time window).

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230710013857.7396-3-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: move the lpuart32_int() below

Move the lpuart32_int() below lpuart_copy_rx_to_tty(), this is a
preparation patch for the next patch to avoid the function declaration,
no actual functional changes.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230710013857.7396-2-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # for imx
Link: https://lore.kernel.org/r/20230724205440.767071-1-robh@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Clear the error flags by writing 1 for lpuart32 platforms

Do not read the data register to clear the error flags for lpuart32
platforms, the additional read may cause the receive FIFO underflow
since the DMA has already read the data register.
Actually all lpuart32 platforms support write 1 to clear those error
bits, let's use this method to better clear the error flags.

Fixes: 42b68768e51b ("serial: fsl_lpuart: DMA support for 32-bit variant")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230801022304.24251-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: add earlycon for imx8ulp platform

Add earlycon support for imx8ulp platform.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20230619080613.16522-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Check the return value of dmaengine_tx_status

Coverity reports the Unchecked return value (CHECKED_RETURN) warning:
Calling dmaengine_tx_status without checking return value.

So here add the return value check for dmaengine_tx_status() function to
make coverity happy.

Fixes: cf9aa72d2f91 ("tty: serial: fsl_lpuart: optimize the timer based EOP logic")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230522025111.3747-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: optimize the timer based EOP logic

DMA transfer may end prematurely due to the DMA Rx timeout even during an
active transfer because a constant timeout does not accurately simulate an
EOP (End Of Package) event. This patch uses a timer to simulate the
hardware EOP event. The timer should only complete a DMA transfer once the
idle period satisfies a specified interval which is baud rate dependent.
The problem has been observed with low baud rates but could occur also
with high baud rates.

Make the DMA Rx timeout baud rate dependent and check the DMA residue count
before copying data to the TTY buffer. If the residue count remains
unchanged since the last interrupt, that indicates no new data was
received. In this case, the DMA should complete as an EOP event. Otherwise,
new data was received during the interval and the EOP condition is not met
so restart the DMA Rx timeout

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230510203359.1353469-1-shenwei.wang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: reduce RX watermark to 0 on LS1028A

LS1028A is using DMA with LPUART. Having RX watermark set to 1, means
DMA transactions are started only after receiving the second character.

On other platforms with newer LPUART IP, Receiver Idle Empty function
initiates the DMA request after the receiver is idling for 4 characters.
But this feature is missing on LS1028A, which is causing a 1-character
delay in the RX direction on this platform.

Set RX watermark to 0 to initiate RX DMA after each character.

Link: https://lore.kernel.org/linux-serial/20230607103459.1222426-1-robert.hodaszi@digi.com/
Fixes: 9ad9df844754 ("tty: serial: fsl_lpuart: Fix the wrong RXWATER setting for rx dma case")
Cc: stable <stable@kernel.org>
Signed-off-by: Robert Hodaszi <robert.hodaszi@digi.com>
Message-ID: <20230609121334.1878626-1-robert.hodaszi@digi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: use UARTCTRL_TXINV to send break instead of UARTCTRL_SBK

LPUART IP now has two known bugs, one is that CTS has higher priority
than the break signal, which causes the break signal sending through
UARTCTRL_SBK may impacted by the CTS input if the HW flow control is
enabled. It exists on all platforms we support in this driver.
So we add a workaround patch for this issue: commit c4c81db5cf8b
("tty: serial: fsl_lpuart: disable the CTS when send break signal").

Another IP bug is i.MX8QM LPUART may have an additional break character
being sent after SBK was cleared. It may need to add some delay between
clearing SBK and re-enabling CTS to ensure that the SBK latch are
completely cleared.

But we found that during the delay period before CTS is enabled, there
is still a risk that Bluetooth data in TX FIFO may be sent out during
this period because of break off and CTS disabled(even if BT sets CTS
line deasserted, data is still sent to BT).

Due to this risk, we have to drop the CTS-disabling workaround for SBK
bugs, use TXINV seems to be a better way to replace SBK feature and
avoid above risk. Also need to disable the transmitter to prevent any
data from being sent out during break, then invert the TX line to send
break. Then disable the TXINV when turn off break and re-enable
transmitter.

Fixes: c4c81db5cf8b ("tty: serial: fsl_lpuart: disable the CTS when send break signal")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230519094751.28948-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: use UARTMODIR register bits for lpuart32 platform

For lpuart32 platforms, UARTMODIR register is used instead of UARTMODEM.
So here should configure the corresponding UARTMODIR register bits to
avoid confusion.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230414022111.20896-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: adjust buffer length to the intended size

Based on the fls function definition provided below, we should not
subtract 1 to obtain the correct buffer length:

fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.

Fixes: 5887ad43ee02 ("tty: serial: fsl_lpuart: Use cyclic DMA for Rx")
Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Link: https://lore.kernel.org/r/20230410195555.1003900-1-shenwei.wang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix crash in lpuart_uport_is_active

For serdev framework, tty->dev is a NULL pointer, lpuart_uport_is_active
calling device_may_wakeup() may cause kernel NULL pointer crash, so here
add the NULL pointer check before using it.

Fixes: 4f5cb8c5e915 ("tty: serial: fsl_lpuart: enable wakeup source for lpuart")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230323110923.24581-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: avoid checking for transfer complete when UARTCTRL_SBK is asserted in lpuart32_tx_empty

According to LPUART RM, Transmission Complete Flag becomes 0 if queuing
a break character by writing 1 to CTRL[SBK], so here need to avoid
checking for transmission complete when UARTCTRL_SBK is asserted,
otherwise the lpuart32_tx_empty may never get TIOCSER_TEMT.

Commit 2411fd94ceaa("tty: serial: fsl_lpuart: skip waiting for
transmission complete when UARTCTRL_SBK is asserted") only fix it in
lpuart32_set_termios(), here also fix it in lpuart32_tx_empty().

Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230323054415.20363-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix race on RX DMA shutdown

From time to time DMA completion can come in the middle of DMA shutdown:

<process ctx>: <IRQ>:
lpuart32_shutdown()
lpuart_dma_shutdown()
del_timer_sync()
lpuart_dma_rx_complete()
lpuart_copy_rx_to_tty()
mod_timer()
lpuart_dma_rx_free()

When the timer fires a bit later, sport->dma_rx_desc is NULL:

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
pc : lpuart_copy_rx_to_tty+0xcc/0x5bc
lr : lpuart_timer_func+0x1c/0x2c
Call trace:
lpuart_copy_rx_to_tty
lpuart_timer_func
call_timer_fn
__run_timers.part.0
run_timer_softirq
__do_softirq
__irq_exit_rcu
irq_exit
handle_domain_irq
gic_handle_irq
call_on_irq_stack
do_interrupt_handler
...

To fix this fold del_timer_sync() into lpuart_dma_rx_free() after
dmaengine_terminate_sync() to make sure timer will not be re-started in
lpuart_copy_rx_to_tty() <= lpuart_dma_rx_complete().

Fixes: 4a8588a1cf86 ("serial: fsl_lpuart: delete timer on shutdown")
Cc: stable <stable@kernel.org>
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Link: https://lore.kernel.org/r/20230309134302.74940-2-alexander.sverdlin@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: skip waiting for transmission complete when UARTCTRL_SBK is asserted

According to LPUART RM, Transmission Complete Flag becomes 0 if queuing
a break character by writing 1 to CTRL[SBK], so here need to skip
waiting for transmission complete when UARTCTRL_SBK is asserted,
otherwise the kernel may stuck here.
And actually set_termios() adds transmission completion waiting to avoid
data loss or data breakage when changing the baud rate, but we don't
need to worry about this when queuing break characters.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/r/20230223093941.31790-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: fix RS485 RTS polariy inverse issue

The previous 'commit 846651eca073 ("serial: fsl_lpuart: RS485 RTS
polariy is inverse")' only fixed the inverse issue on lpuart 8bit
platforms.

This is a follow-up patch to fix the RS485 polarity inverse
issue on lpuart 32bit platforms.

Fixes: 03895cf41d18 ("tty: serial: fsl_lpuart: Add support for RS-485")
Reported-by: Sherry Sun <sherry.sun@nxp.com>
Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Link: https://lore.kernel.org/r/20230207162420.3647904-1-shenwei.wang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: add imx8ulp support

The lpuart of imx8ulp is basically the same as imx7ulp, but it supports
some new features based on imx7ulp, such as it can assert the DMA
request on EOP(end-of-packet).

Here add lpuart support for imx8ulp, and rx_watermark is set to 3 as
imx8ulp RX FIFO depth is 8.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130064449.9564-7-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: set RTS watermark for lpuart

Add RTS watermark support for LPUART. The RX RTS_B output negates when
the number of empty words in the receive FIFO is greater or equal to
RTSWATER. Here set the RTSWATER to half of the rxfifo_size.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130064449.9564-6-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Enable Receiver Idle Empty function for LPUART

With the growth of rx watermark, it's useful to enable the Receiver Idle
Empty function, it can assert the RDRF(Receive Data Register Full Flag)
when the receiver is idle for a number of idle characters and the FIFO
is not empty. It will generate a DMA request or interrupt, which can
avoid receive data being trapped in the RX FIFO since the number of
words received is less than the watermark.

Here set the RXIDEN as 0x3 which enable the RDRF assertion due to
partially filled FIFO when receiver is idle for 4 characters.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130064449.9564-5-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Fix the wrong RXWATER setting for rx dma case

The RXWATER value must be greater than 0 according to the LPUART
reference manual. And when the number of datawords in the receive
FIFO is greater than RXWATER, an interrupt or a DMA request is
generated, so no need to set the different value for lpuart interrupt
case and dma case. Here delete the wrong RXWATER setting for dma case
directly.

Fixes: 42b68768e51b ("serial: fsl_lpuart: DMA support for 32-bit variant")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130064449.9564-4-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: set receive watermark for imx8qxp platform

Since imx8qxp RX FIFO depth is 64 datawords, it will be better to set
the rx watermark as 31, which means when the number of datawords in the
receive FIFO(>= 32) is greater than the watermark, an interrupt or a DMA
request is generated.
Also keep the console rx watermark as 1 to make sure it responsive.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130064449.9564-3-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: make rx_watermark configurable for different platforms

Add rx_watermark parameter for struct lpuart_port to make the receive
watermark configurable for different platforms.
No function changed.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130064449.9564-2-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: don't enable receiver/transmitter before rx/tx dma ready

lpuart32_setup_watermark_enable() will configure the UART FIFO and
watermark, also enable the receiver and transmitter, this should be done
after the rx/tx dma steup ready.

Also add lpuart32_hw_disable() to make sure the receiver/transmitter and
interrupts are disabled during the dma steup.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130054107.9119-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: increase maximum uart_nr to eight

Some SoCs like the i.MX93 have aliases for up to eight UARTs, see:
https://github.com/torvalds/linux/blob/v6.1/arch/arm64/boot/dts/freescale/imx93.dtsi#L31-L38

Increase UART_NR from 6 to 8 to support lpuart7 and lpuart8 and avoid
initialization failures like the following:

[ 0.837146] fsl-lpuart 42690000.serial: serial6 out of range
[ 0.842814] fsl-lpuart: probe of 42690000.serial failed with error -22

Signed-off-by: Nate Drude <nate.d@variscite.com>
Reviewed-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221222145634.2217793-1-nate.d@variscite.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: disable the break condition when shutdown the uart port

Need to disable the break condition for lpuart driver when closing
the uart port like other uart drivers do.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221214031137.28815-3-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: disable the CTS when send break signal

LPUART IP has a bug that it treats the CTS as higher priority than the
break signal, which cause the break signal sending through UARTCTRL_SBK
may impacted by the CTS input if the HW flow control is enabled.

Add this workaround patch to fix the IP bug, we can disable CTS before
asserting SBK to avoid any interference from CTS, and re-enable it when
break off.

Such as for the bluetooth chip power save feature, host can let the BT
chip get into sleep state by sending a UART break signal, and wake it up
by turning off the UART break. If the BT chip enters the sleep mode
successfully, it will pull up the CTS line, if the BT chip is woken up,
it will pull down the CTS line. If without this workaround patch, the
UART TX pin cannot send the break signal successfully as it affected by
the BT CTS pin. After adding this patch, the BT power save feature can
work well.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221214031137.28815-2-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: clear LPUART Status Register in lpuart32_shutdown()

The LPUART Status Register needs to be cleared when closing the uart
port to get a clean environment when reopening the uart.

Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221125101953.18753-4-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: disable Rx/Tx DMA in lpuart32_shutdown()

UARTBAUD_RDMAE and UARTBAUD_TDMAE are enabled in lpuart32_startup(), but
lpuart32_shutdown() not disable them, only free the dma ring buffer and
release the dma channels, so here disable the Rx/Tx DMA first in
lpuart32_shutdown().

Fixes: 42b68768e51b ("serial: fsl_lpuart: DMA support for 32-bit variant")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221125101953.18753-3-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: only enable Idle Line Interrupt for non-dma case

For the lpuart driver, the Idle Line Interrupt Enable now is only needed
for the CPU mode, so enable the UARTCTRL_ILIE at the correct place, and
clear it when shutdown.

Also need to configure the suitable UARTCTRL_IDLECFG, now the value is
0x7, represent 128 idle characters will trigger the Idle Line Interrupt.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221125101953.18753-2-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: switch to new dmaengine_terminate_* API

Convert dmaengine_terminate_all() calls to synchronous and asynchronous
versions where appropriate.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221123023619.30173-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Use pm_ptr() to avoid need to make pm __maybe_unused

Use pm_ptr() to remove the need to mark the pm functions as
__maybe_unused when the kernel is built without CONFIG_PM support.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221110113859.8485-4-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Add runtime pm support

Add runtime pm support to manage the lpuart clock.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221110113859.8485-3-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: enable wakeup source for lpuart

LPUART supports both synchronous wakeup and asynchronous wakeup(wakeup
the system when the UART clocks are shut-off), the synchronous wakeup is
configured by UARTCTRL_RIE interrupt, and the asynchronous wakeup is
configured by UARTBAUD_RXEDGIE interrupt.

Add lpuart_uport_is_active() to determine if the uart port needs to get
into the suspend states, also add lpuart_suspend_noirq() and
lpuart_resume_noirq() to enable and disable the wakeup irq bits if the
uart port needs to be set as wakeup source.

When use lpuart with DMA mode, it still needs to switch to the cpu mode
in .suspend() that enable cpu interrupts RIE and RXEDGIE as wakeup
source, after system resume back, needs to setup DMA again, .resume()
will share the HW setup code with .startup(), so abstract the same code
to the api like lpuart32_hw_setup().

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221110113859.8485-2-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Use uart_xmit_advance()

Take advantage of the new uart_xmit_advance() helper.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20221019091151.6692-17-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: use uart_port_tx() helper

uart_port_tx() is a new helper to send characters to the device. Use it
in these drivers.

Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Claudiu Beznea <claudiu.beznea@microchip.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20221004104927.14361-3-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: don't break the on-going transfer when global reset

lpuart_global_reset() shouldn't break the on-going transmit engine, need
to recover the on-going data transfer after reset.

This can help earlycon here, since commit 60f361722ad2 ("serial:
fsl_lpuart: Reset prior to registration") moved lpuart_global_reset()
before uart_add_one_port(), earlycon is writing during global reset,
as global reset will disable the TX and clear the baud rate register,
which caused the earlycon cannot work any more after reset, needs to
restore the baud rate and re-enable the transmitter to recover the
earlycon write.

Also move the lpuart_global_reset() down, then we can reuse the
lpuart32_tx_empty() without declaration.

Fixes: bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset for imx7ulp and imx8qxp")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221024085844.22786-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Deassert Transmit Enable on probe in driver-specific way

When a UART port is newly registered, uart_configure_port() seeks to
deassert RS485 Transmit Enable by setting the RTS bit in port->mctrl.
However a number of UART drivers interpret a set RTS bit as *assertion*
instead of deassertion: Affected drivers include those using
serial8250_em485_config() (except 8250_bcm2835aux.c) and some using
mctrl_gpio (e.g. imx.c).

Since the interpretation of the RTS bit is driver-specific, it is not
suitable as a means to centrally deassert Transmit Enable in the serial
core. Instead, the serial core must call on drivers to deassert it in
their driver-specific way. One way to achieve that is to call
->rs485_config(). It implicitly deasserts Transmit Enable.

So amend uart_configure_port() and uart_resume_port() to invoke
uart_rs485_config(). That allows removing calls to uart_rs485_config()
from drivers' ->probe() hooks and declaring the function static.

Skip any invocation of ->set_mctrl() if RS485 is enabled. RS485 has no
hardware flow control, so the modem control lines are irrelevant and
need not be touched. When leaving RS485 mode, reset the modem control
lines to the state stored in port->mctrl. That way, UARTs which are
muxed between RS485 and RS232 transceivers drive the lines correctly
when switched to RS232. (serial8250_do_startup() historically raises
the OUT1 modem signal because otherwise interrupts are not signaled on
ancient PC UARTs, but I believe that no longer applies to modern,
RS485-capable UARTs and is thus safe to be skipped.)

imx.c modifies port->mctrl whenever Transmit Enable is asserted and
deasserted. Stop it from doing that so port->mctrl reflects the RS232
line state.

8250_omap.c deasserts Transmit Enable on ->runtime_resume() by calling
->set_mctrl(). Because that is now a no-op in RS485 mode, amend the
function to call serial8250_em485_stop_tx().

fsl_lpuart.c retrieves and applies the RS485 device tree properties
after registering the UART port. Because applying now happens on
registration in uart_configure_port(), move retrieval of the properties
ahead of uart_add_one_port().

Link: https://lore.kernel.org/all/20220329085050.311408-1-matthias.schiffer@ew.tq-group.com/
Link: https://lore.kernel.org/all/8f538a8903795f22f9acc94a9a31b03c9c4ccacb.camel@ginzinger.com/
Fixes: d3b3404df318 ("serial: Fix incorrect rs485 polarity on uart open")
Cc: stable@vger.kernel.org # v4.14+
Reported-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reported-by: Roosen Henri <Henri.Roosen@ginzinger.com>
Tested-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/2de36eba3fbe11278d5002e4e501afe0ceaca039.1663863805.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: disable dma rx/tx use flags in lpuart_dma_shutdown

lpuart_dma_shutdown tears down lpuart dma, but lpuart_flush_buffer can
still occur which in turn tries to access dma apis if lpuart_dma_tx_use
flag is true. At this point since dma is torn down, these dma apis can
abort. Set lpuart_dma_tx_use and the corresponding rx flag
lpuart_dma_rx_use to false in lpuart_dma_shutdown so that dmas are not
accessed after they are relinquished.

Otherwise, when try to kill btattach, kernel may panic. This patch may
fix this issue.
root@imx8ulpevk:~# btattach -B /dev/ttyLP2 -S 115200
^C[ 90.182296] Internal error: synchronous external abort: 96000210 [#1] PREEMPT SMP
[ 90.189806] Modules linked in: moal(O) mlan(O)
[ 90.194258] CPU: 0 PID: 503 Comm: btattach Tainted: G O 5.15.32-06136-g34eecdf2f9e4 #37
[ 90.203554] Hardware name: NXP i.MX8ULP 9X9 EVK (DT)
[ 90.208513] pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 90.215470] pc : fsl_edma3_disable_request+0x8/0x60
[ 90.220358] lr : fsl_edma3_terminate_all+0x34/0x20c
[ 90.225237] sp : ffff800013f0bac0
[ 90.228548] x29: ffff800013f0bac0 x28: 0000000000000001 x27: ffff000008404800
[ 90.235681] x26: ffff000008404960 x25: ffff000008404a08 x24: ffff000008404a00
[ 90.242813] x23: ffff000008404a60 x22: 0000000000000002 x21: 0000000000000000
[ 90.249946] x20: ffff800013f0baf8 x19: ffff00000559c800 x18: 0000000000000000
[ 90.257078] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[ 90.264211] x14: 0000000000000003 x13: 0000000000000000 x12: 0000000000000040
[ 90.271344] x11: ffff00000600c248 x10: ffff800013f0bb10 x9 : ffff000057bcb090
[ 90.278477] x8 : fffffc0000241a08 x7 : ffff00000534ee00 x6 : ffff000008404804
[ 90.285609] x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff0000055b3480
[ 90.292742] x2 : ffff8000135c0000 x1 : ffff00000534ee00 x0 : ffff00000559c800
[ 90.299876] Call trace:
[ 90.302321] fsl_edma3_disable_request+0x8/0x60
[ 90.306851] lpuart_flush_buffer+0x40/0x160
[ 90.311037] uart_flush_buffer+0x88/0x120
[ 90.315050] tty_driver_flush_buffer+0x20/0x30
[ 90.319496] hci_uart_flush+0x44/0x90
[ 90.323162] +0x34/0x12c
[ 90.327253] tty_ldisc_close+0x38/0x70
[ 90.331005] tty_ldisc_release+0xa8/0x190
[ 90.335018] tty_release_struct+0x24/0x8c
[ 90.339022] tty_release+0x3ec/0x4c0
[ 90.342593] __fput+0x70/0x234
[ 90.345652] ____fput+0x14/0x20
[ 90.348790] task_work_run+0x84/0x17c
[ 90.352455] do_exit+0x310/0x96c
[ 90.355688] do_group_exit+0x3c/0xa0
[ 90.359259] __arm64_sys_exit_group+0x1c/0x20
[ 90.363609] invoke_syscall+0x48/0x114
[ 90.367362] el0_svc_common.constprop.0+0xd4/0xfc
[ 90.372068] do_el0_svc+0x2c/0x94
[ 90.375379] el0_svc+0x28/0x80
[ 90.378438] el0t_64_sync_handler+0xa8/0x130
[ 90.382711] el0t_64_sync+0x1a0/0x1a4
[ 90.386376] Code: 17ffffda d503201f d503233f f9409802 (b9400041)
[ 90.392467] ---[ end trace 2f60524b4a43f1f6 ]---
[ 90.397073] note: btattach[503] exited with preempt_count 1
[ 90.402636] Fixing recursive fault but reboot is needed!

Fixes: 6250cc30c4c4 ("tty: serial: fsl_lpuart: Use scatter/gather DMA for Tx")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Thara Gopinath <tgopinath@microsoft.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220920111703.1532-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Remove custom frame size calculation

The number of bits can be calculated using tty_get_frame_size(), no
need for the driver to do it on its own. Change bits to unsigned and
baud too since we're touching the declarations line anyway (the
respective core functions are typed unsigned).

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220830084925.5608-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Make ->set_termios() old ktermios const

There should be no reason to adjust old ktermios which is going to get
discarded anyway.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220816115739.10928-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Fix comment typo

The double `as' is duplicated in the comment, remove one.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Link: https://lore.kernel.org/r/20220803104208.4127-1-wangborong@cdjrlc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Reset prior to registration

Since commit bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset
for imx7ulp and imx8qxp"), certain i.MX UARTs are reset after they've
already been registered. Register state may thus be clobbered after
user space has begun to open and access the UART.

Avoid by performing the reset prior to registration.

Fixes: bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset for imx7ulp and imx8qxp")
Cc: stable@vger.kernel.org # v5.15+
Cc: Fugang Duan <fugang.duan@nxp.com>
Cc: Sherry Sun <sherry.sun@nxp.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/72fb646c1b0b11c989850c55f52f9ff343d1b2fa.1662884345.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete

When the user initializes the uart port, and waits for the transmit
engine to complete in lpuart32_set_termios(), if the UART TX fifo has
dirty data and the UARTMODIR enable the flow control, the TX fifo may
never be empty. So here we should disable the flow control first to make
sure the transmit engin can complete.

Fixes: 380c966c093e ("tty: serial: fsl_lpuart: add 32-bit register interface support")
Cc: stable <stable@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220821101527.10066-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: RS485 RTS polariy is inverse

The setting of RS485 RTS polarity is inverse in the current driver.

When the property of 'rs485-rts-active-low' is enabled in the dts node,
the RTS signal should be LOW during sending. Otherwise, if there is no
such a property, the RTS should be HIGH during sending.

Fixes: 03895cf41d18 ("tty: serial: fsl_lpuart: Add support for RS-485")
Cc: stable <stable@kernel.org>
Signed-off-by: Nicolas Diaz <nicolas.diaz@nxp.com>
Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Link: https://lore.kernel.org/r/20220805144529.604856-1-shenwei.wang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: correct the count of break characters

The LPUART can't distinguish between a break signal and a framing error,
so need to count the break characters if there is a framing error and
received data is zero instead of the parity error.

Fixes: 5541a9bacfe5 ("serial: fsl_lpuart: handle break and make sysrq work")
Reviewed-by: Michael Walle <michael@walle.cc>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220725050115.12396-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: zero out parity bit in CS7 mode

The LPUART hardware doesn't zero out the parity bit on the received
characters. This behavior won't impact the use cases of CS8 because
the parity bit is the 9th bit which is not currently used by software.
But the parity bit for CS7 must be zeroed out by software in order to
get the correct raw data.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Link: https://lore.kernel.org/r/20220714185858.615373-1-shenwei.wang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Embed rs485_supported to uart_port

Embed rs485_supported to uart_port to allow serial core to tweak it as
needed.

Reviewed-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220704094515.6831-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: take termios_rwsem for ->rs485_config() & pass termios as param

To be able to alter ADDRB within ->rs485_config(), take termios_rwsem
before calling ->rs485_config() and pass termios.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Call core's sanitization and remove custom one

Serial core handles serial_rs485 sanitization. Remove custom
sanitization from lpuart_config_rs485.

This change loses dev_err when SER_RS485_RX_DURING_TX is set due to
incorrect configuration. Other drivers do not do similar prinout for
full-duplex case and it should be done in serial core if it is
desirable to notify on this condition. Personally, I doesn't see it
important because the kernel gracefully downgrades to half-duplex.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-31-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Fill in rs485_supported

Add information on supported serial_rs485 features.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-16-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Add uart_rs485_config()

A few serial drivers make a call to rs485_config() themselves (all
these seem to relate to init). Convert them all to use a common helper
which makes it easy to make adjustments on tasks related to it as
serial_rs485 struct sanitization is going to be added.

In pci_fintek_setup() (in 8250_pci.c), the rs485_config() call was made
with NULL, however, it can be changed to pass uart_port's rs485 struct.
No other callers should pass NULL into rs485_config() so the NULL check
can now be eliminated.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Remove unnecessary clearing for CRTSCTS

if (termios->c_cflag & CRTSCTS) guarantees that CRTSCTS is not ever set
in the else block so clearing it is unnecessary.

While at it, remove also one pair of extra parenthesis.

Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220513082906.11096-5-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: remove the count initialization as it is not needed

No need to initialize the count variable in lpuart_copy_rx_to_tty(),
so let's remove it here.

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220418021844.29591-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix potential bug when using both of_alias_get_id and ida_simple_get

Now fsl_lpuart driver use both of_alias_get_id() and ida_simple_get() in
.probe(), which has the potential bug. For example, when remove the
lpuart7 alias in dts, of_alias_get_id() will return error, then call
ida_simple_get() to allocate the id 0 for lpuart7, this may confilct
with the lpuart4 which has alias 0.

aliases {
...
serial0 = &lpuart4;
serial1 = &lpuart5;
serial2 = &lpuart6;
serial3 = &lpuart7;
}

So remove the ida_simple_get() in .probe(), return an error directly
when calling of_alias_get_id() fails, which is consistent with other
uart drivers behavior.

Fixes: 3bc3206e1c0f ("serial: fsl_lpuart: Remove the alias node dependence")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220321112211.8895-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: remove redundant code in rs485_config functions

In uart_set_rs485_config() the serial core already ensures that only one of
both options RTS on send or RTS after send is set. It also assigns the
passed serial_rs485 struct to the uart port.

So remove the check and the assignment from the drivers rs485_config()
function to avoid redundancy.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20220410104642.32195-9-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fsl_lpuart: Don't enable interrupts too early

If an irq is pending when devm_request_irq() is called, the irq
handler will cause a NULL pointer access because initialisation
is not done yet.

Fixes: 9d7ee0e28da59 ("tty: serial: lpuart: avoid report NULL interrupt")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Indan Zupancic <Indan.Zupancic@mep-info.com>
Link: https://lore.kernel.org/r/20220505114750.45423-1-Indan.Zupancic@mep-info.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: make uart_console_write->putchar()'s character an unsigned char

Currently, uart_console_write->putchar's second parameter (the
character) is of type int. It makes little sense, provided uart_console_write()
accepts the input string as "const char *s" and passes its content -- the
characters -- to putchar(). So switch the character's type to unsigned
char.

We don't use char as that is signed on some platforms. That would cause
troubles for drivers which (implicitly) cast the char to u16 when
writing to the device. Sign extension would happen in that case and the
value written would be completely different to the provided char. DZ is
an example of such a driver -- on MIPS, it uses u16 for dz_out in
dz_console_putchar().

Note we do the char -> uchar conversion implicitly in
uart_console_write(). Provided we do not change size of the data type,
sign extension does not happen there, so the problem is void.

This makes the types consistent and unified with the rest of the uart
layer, which uses unsigned char in most places already. One exception is
xmit_buf, but that is going to be converted later.

Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: "Maciej W. Rozycki" <macro@orcam.me.uk>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: Karol Gugala <kgugala@antmicro.com>
Cc: Mateusz Holenko <mholenko@antmicro.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Taichi Sugaya <sugaya.taichi@socionext.com>
Cc: Takao Orito <orito.takao@socionext.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Baolin Wang <baolin.wang7@gmail.com>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <peter@korsgaard.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com> [atmel_serial]
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Neil Armstrong <narmstrong@baylibre.com> # meson_serial
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220303080831.21783-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: count tty buffer overruns

Added support for counting the tty buffer overruns in fsl_lpuart driver
like other uart drivers.

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220111085130.5817-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Add i.MXRT1050 support

Add support for i.MXRT1050's uart.

Cc: Giulio Benetti <giulio.benetti@benettiengineering.com>
Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>
Link: https://lore.kernel.org/r/20211215220538.4180616-8-Mr.Bossman075@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: add timeout for wait_event_interruptible in .shutdown()

Use wait_event_interruptible in lpuart_dma_shutdown isn't a reasonable
behavior, since it may cause the system hang here if the condition
!sport->dma_tx_in_progress never to be true in some corner case, such as
when enable the flow control, the dma tx request may never be completed
due to the peer's CTS setting when run .shutdown().

So here change to use wait_event_interruptible_timeout instead of
wait_event_interruptible, the tx dma will be forcibly terminated if the
tx dma request cannot be completed within 300ms.
Considering the worst tx dma case is to have a 4K bytes tx buffer, which
would require about 300ms to complete when the baudrate is 115200.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20211203030441.22873-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "tty: serial: fsl_lpuart: drop earlycon entry for i.MX8QXP"

Revert commit b4b844930f27 ("tty: serial: fsl_lpuart: drop earlycon entry
for i.MX8QXP"), because this breaks earlycon support on imx8qm/imx8qxp.
While it is true that for earlycon there is no difference between
i.MX8QXP and i.MX7ULP (for now at least), there are differences
regarding clocks and fixups for wakeup support. For that reason it was
deemed unacceptable to add the imx7ulp compatible to device tree in
order to get earlycon working again.

Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/20211124073109.805088-1-alexander.stein@ew.tq-group.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: do software reset for imx7ulp and imx8qxp

Do software reset for communication port on imx7ulp and imx8qxp after
the port is registered if the UART controller support the feature.

Do partition reset with LPUART's power on, LPUART registers will
keep the previous status, like on i.MX8QXP platform, which is not
expected action, so need to set the RST bit of GLOBAL register to reset
all uart internal logic and registers.

Currently, only i.MX7ULP and i.MX8QXP LPUART controllers include
global register that support the software reset.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20210823091801.17447-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: enable two stop bits for lpuart32

Add two stop bits support.
User can run the command to enable two stop bits for test:
stty cstopb -F /dev/ttyLPx

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20210823081733.31941-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix the wrong mapbase value

Register offset needs to be applied on mapbase also.
dma_tx/rx_request use the physical address of UARTDATA.
Register offset is currently only applied to membase (the
corresponding virtual addr) but not on mapbase.

Fixes: 24b1e5f0e83c ("tty: serial: lpuart: add imx7ulp support")
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Adriana Reus <adriana.reus@nxp.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Signed-off-by: Andy Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20210819021033.32606-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: check dma_tx_in_progress in tx dma callback

There have a corner case that tx DMA .callback() is coming after
.flush_buffer(), then .callback() should check dma_tx_in_progress
flag and return in directly.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20210817100203.21300-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix the wrong return value in lpuart32_get_mctrl

Patch e60c2991f18b make the lpuart32_get_mctrl always return 0, actually
this will break the functions of device which use flow control such as
Bluetooth.
For lpuart32 plaform, the hardware can handle the CTS automatically.
So we should set TIOCM_CTS active. Also need to set CAR and DSR active.

Patch has been tested on lpuart32 platforms such as imx8qm and imx8ulp.

Fixes: e60c2991f18b ("serial: fsl_lpuart: remove RTSCTS handling from get_mctrl()")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20210729083109.31541-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: disable DMA for console and fix sysrq

SYSRQ doesn't work with DMA. This is because there is no error
indication whether a symbol had a framing error or not. Actually,
this is not completely correct, there is a bit in the data register
which is set in this case, but we'd have to read change the DMA access
to 16 bit and we'd need to post process the data, thus make the DMA
pointless in the first place.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-10-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: add loopback support

The LPUART can loop the RX and TX signal. Add support for it.

Please note, this was only tested on the 32 bit version of the LPUART.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-9-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: remove manual RTSCTS control from 8-bit LPUART

The LPUART doesn't have the ability to control the RTS or CTS line
manually. Instead it will set it automatically when data is send or
handle it when data is received. Thus drop the wrong code in set_mctrl.
For the 32 bit version this was already done in the commit 2b30efe2e88a
("tty: serial: lpuart: Remove unnecessary code from set_mctrl"). Keep
the 8-bit version in sync and remove it there, too.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-8-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: remove RTSCTS handling from get_mctrl()

The wrong code in set_mctrl() was already removed in commit 2b30efe2e88a
("tty: serial: lpuart: Remove unnecessary code from set_mctrl"), but the
code in get_mctrl() wasn't removed. It will not return the state of the
RTS or CTS line but whether automatic flow control is enabled, which is
wrong for the get_mctrl(). Thus remove it.

Fixes: 2b30efe2e88a ("tty: serial: lpuart: Remove unnecessary code from set_mctrl")
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-7-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: handle break and make sysrq work

Although there is already sysrq characters handling, a break condition
was never detected. Add support for it.

The LPUART can't distinguish between a framing error and a break
condition. We assume it is a break if the received data is all zero.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-6-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: split sysrq handling

Instead of uart_handle_sysrq_char() use uart_prepare_sysrq_char() and
uart_unlock_and_check_sysrq(). This will call handle_sysrq() without
holding the port lock, which in turn let us drop the spin_trylock hack.

Suggested-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-5-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: don't restore interrupt state in ISR

>From commit 75f4e830fa9c ("serial: do not restore interrupt state in
sysrq helper"):

Since commit 81e2073c175b ("genirq: Disable interrupts for force
threaded handlers") interrupt handlers that are not explicitly
requested as threaded are always called with interrupts disabled and
there is no need to save the interrupt state when taking the port
lock.

Apply this also to fsl_lpuart in prepartion for sysrq handling with
uart_unlock_and_check_sysrq().

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-4-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: use UARTDATA_MASK macro

Use the corresponding macro instead of the magic number. While at it,
drop the useless cast to "unsigned char".

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-3-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: don't modify arbitrary data on lpuart32

lpuart_rx_dma_startup() is used for both the 8 bit and the 32 bit
version of the LPUART. Modify the UARTCR only for the 8 bit version.

Fixes: f4eef224a09f ("serial: fsl_lpuart: add sysrq support when using dma")
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-2-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix the potential risk of division or modulo by zero

We should be very careful about the register values that will be used
for division or modulo operations, althrough the possibility that the
UARTBAUD register value is zero is very low, but we had better to deal
with the "bad data" of hardware in advance to avoid division or modulo
by zero leading to undefined kernel behavior.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20210427021226.27468-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Use of_device_get_match_data()

The retrieval of driver data via of_device_get_match_data() can make
the code simpler.

Use of_device_get_match_data() to simplify the code.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20210118124447.1632092-1-festevam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: LS1021A has a FIFO size of 16 words, like LS1028A

Prior to the commit that this one fixes, the FIFO size was derived from
the read-only register LPUARTx_FIFO[TXFIFOSIZE] using the following
formula:

TX FIFO size = 2 ^ (LPUARTx_FIFO[TXFIFOSIZE] - 1)

The documentation for LS1021A is a mess. Under chapter 26.1.3 LS1021A
LPUART module special consideration, it mentions TXFIFO_SZ and RXFIFO_SZ
being equal to 4, and in the register description for LPUARTx_FIFO, it
shows the out-of-reset value of TXFIFOSIZE and RXFIFOSIZE fields as "011",
even though these registers read as "101" in reality.

And when LPUART on LS1021A was working, the "101" value did correspond
to "16 datawords", by applying the formula above, even though the
documentation is wrong again (!!!!) and says that "101" means 64 datawords
(hint: it doesn't).

So the "new" formula created by commit f77ebb241ce0 has all the premises
of being wrong for LS1021A, because it relied only on false data and no
actual experimentation.

Interestingly, in commit c2f448cff22a ("tty: serial: fsl_lpuart: add
LS1028A support"), Michael Walle applied a workaround to this by manually
setting the FIFO widths for LS1028A. It looks like the same values are
used by LS1021A as well, in fact.

When the driver thinks that it has a deeper FIFO than it really has,
getty (user space) output gets truncated.

Many thanks to Michael for pointing out where to look.

Fixes: f77ebb241ce0 ("tty: serial: fsl_lpuart: correct the FIFO depth size")
Suggested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20201023013429.3551026-1-vladimir.oltean@nxp.com
Reviewed-by：Fugang Duan <fugang.duan@nxp.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: add sysrq support when using dma

Add handling of magic sysrq keys when using dma/edma.

Tested by sending BREAK followed by a sysrq command inside
a 5 secs time window, by:

echo 1 > /proc/sys/kernel/sysrq

BREAK + h, t, e, b, c

Tested also sending a command after 5 secs after BREAK, that's
properly ignored.

Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Link: https://lore.kernel.org/r/20201004161144.1307174-1-angelo.dureghello@timesys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix lpuart32_poll_get_char

The watermark is set to 1, so we need to input two chars to trigger RDRF
using the original logic. With the new logic, we could always get the
char when there is data in FIFO.

Suggested-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20200929095509.21680-1-peng.fan@nxp.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: fix lpuart32_write usage

The 2nd and 3rd parameter were wrongly used, and cause kernel abort when
doing kgdb debug.

Fixes: 1da17d7cf8e2 ("tty: serial: fsl_lpuart: Use appropriate lpuart32_* I/O funcs")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20200929091920.22612-1-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Fix typo in "transfer"

Fix two occurrences where "transfer" is spelled incorrectly.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20200818224457.16507-1-festevam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: minimum baud rate support

The formula for the baud rate is
baud rate = "baud clock / ((OSR+1) × SBR)

Algorithm used in function lpuart32_serial_setbrg() only changes
the SBR. Even with maxmum value put in, OSR stays at 0x7 and the
lowest baud rate would be ~ 2600 bps

Update the algorithm to allow driver operation at 1200,2400 or 600 bps

Signed-off-by: Vabhav Sharma <vabhav.sharma@nxp.com>
Link: https://lore.kernel.org/r/1593170434-13524-1-git-send-email-vabhav.sharma@oss.nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Use __maybe_unused instead of #if CONFIG_PM_SLEEP

Use __maybe_unused for power management related functions to simplify
the code.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Link: https://lore.kernel.org/r/1589547481-25932-1-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Allow uart_get_rs485_mode() to return errno

We're about to amend uart_get_rs485_mode() to support a GPIO pin for
rs485 bus termination. Retrieving the GPIO descriptor may fail, so
allow uart_get_rs485_mode() to return an errno and change all callers
to check for failure.

The GPIO descriptor is going to be stored in struct uart_port. Pass
that struct to uart_get_rs485_mode() in lieu of a struct device and
struct serial_rs485, both of which are directly accessible from struct
uart_port.

A few drivers call uart_get_rs485_mode() before setting the struct
device pointer in struct uart_port. Shuffle those calls around where
necessary.

[Heiko Stuebner did the ar933x_uart.c portion, hence his Signed-off-by.]

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Change DMA failure messages to debug level

Currently the following messages are seen when booting i.MX8QXP:

fsl-lpuart 5a060000.serial: DMA tx channel request failed, operating without tx DMA (-19)
fsl-lpuart 5a060000.serial: DMA rx channel request failed, operating without rx DMA (-19)

It is not really useful to have such messages on every boot, so change
them to debug level instead.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20200416153453.18825-1-festevam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: make coverity happy

Coverity reports the following:

var_compare_op: Comparing chan to null implies that chan might be null.

1234 if (chan)
1235 dmaengine_terminate_all(chan);
1236

Dereference after null check (FORWARD_NULL)
var_deref_op: Dereferencing null pointer chan.

1237 dma_unmap_sg(chan->device->dev, &sport->rx_sgl, 1, DMA_FROM_DEVICE);

Technically, this is correct. But lpuart_dma_rx_free() is guarded by
lpuart_dma_rx_use which is only true if there is a dma channel, see
lpuart_rx_dma_startup(). In any way, this looks bogus. So remove
the superfluous "if (chan)" check and make coverity happy.

Fixes: a092ab25fdaa ("tty: serial: fsl_lpuart: fix DMA mapping")
Signed-off-by: Michael Walle <michael@walle.cc>
Reported-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20200403174942.9594-1-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix return value checking

The return value of lpuart_dma_tx_request() is an negative errno on
failure and zero on success.

Fixes: 159381df1442f ("tty: serial: fsl_lpuart: fix DMA operation when using IOMMU")
Reported-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20200325090658.25967-2-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: move dma_request_chan()

Move dma_request_chan() out of the atomic context. First this call
should not be in the atomic context at all and second the
dev_info_once() may cause a hang because because the console takes this
spinlock, too.

Fixes: 159381df1442f ("tty: serial: fsl_lpuart: fix DMA operation when using IOMMU")
Reported-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
Tested-by: Leonard Crestez <leonard.crestez@nxp.com>
Link: https://lore.kernel.org/r/20200325090658.25967-1-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: add LS1028A earlycon support

Add a early_console_setup() for the LS1028A SoC with 32bit, little
endian access. If the bootloader does a fixup of the clock-frequency
node the baudrate divisor register will automatically be set.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-5-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: add LS1028A support

The LS1028A uses little endian register access and has a different FIFO
size encoding.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-4-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix DMA mapping

Use the correct device to request the DMA mapping. Otherwise the IOMMU
doesn't get the mapping and it will generate a page fault.

The error messages look like:
[ 19.012140] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xbbfff800, fsynr=0x3e0021, cbfrsynra=0x828, cb=9
[ 19.023593] arm-smmu 5000000.iommu: Unhandled context fault: fsr=0x402, iova=0xbbfff800, fsynr=0x3e0021, cbfrsynra=0x828, cb=9

This was tested on a custom board with a LS1028A SoC.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-3-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix DMA operation when using IOMMU

The DMA channel might not be available at probe time. This is esp. the
case if the DMA controller has an IOMMU mapping.

There is also another caveat. If there is no DMA controller at all,
dma_request_chan() will also return -EPROBE_DEFER. Thus we cannot test
for -EPROBE_DEFER in probe(). Otherwise the lpuart driver will fail to
probe if, for example, the DMA driver is not enabled in the kernel
configuration.

To workaround this, we request the DMA channel in _startup(). Other
serial drivers do it the same way.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200306214433.23215-2-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: free IDs allocated by IDA

Since commit 3bc3206e1c0f ("serial: fsl_lpuart: Remove the alias node
dependence") the port line number can also be allocated by IDA, but in
case of an error the ID will no be removed again. More importantly, any
ID will be freed in remove(), even if it wasn't allocated but instead
fetched by of_alias_get_id(). If it was not allocated by IDA there will
be a warning:
WARN(1, "ida_free called for id=%d which is not allocated.\n", id);

Move the ID allocation more to the end of the probe() so that we still
can use plain return in the first error cases.

Fixes: 3bc3206e1c0f ("serial: fsl_lpuart: Remove the alias node dependence")
Signed-off-by: Michael Walle <michael@walle.cc>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200303174306.6015-3-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "tty: serial: fsl_lpuart: drop EARLYCON_DECLARE"

This reverts commit a659652f6169240a5818cb244b280c5a362ef5a4.

This broke the earlycon on LS1021A processors because the order of the
earlycon_setup() functions were changed. Before the commit the normal
lpuart32_early_console_setup() was called. After the commit the
lpuart32_imx_early_console_setup() is called instead.

Fixes: a659652f6169 ("tty: serial: fsl_lpuart: drop EARLYCON_DECLARE")
Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20200303174306.6015-2-michael@walle.cc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: drop earlycon entry for i.MX8QXP

i.MX8QXP lpuart is compatible with i.MX7ULP, so no need
an extra entry for i.MX8QXP.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1576822230-23125-4-git-send-email-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: support UPIO_MEM32 for lpuart32

"earlycon" no need to specify the value string since it uses
stdout-path parameters. However when earlycon and normal console
are not using the same uart port, we need specify value string
to earlycon, this is what we need to do when support dual linux
using jailhouse hypervisor. The 2nd linux will use the uart
of the 1st linux as earlycon.

earlycon=lpuart32,mmio32,0x5a060010,115200 not work for i.MX8QXP.
It is because lpuart32_early_console_setup not support little endian.

Since the original code is to support UPIO_MEM32BE, so if not
UPIO_MEM32, we still take it as UPIO_MEM32BE

Acked-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1576822230-23125-3-git-send-email-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: drop EARLYCON_DECLARE

EARLYCON_DECLARE is just a wrapper of OF_EARLYCON_DECLARE,
since we already have OF_EARLYCON_DECLARE for lpuart and lpuart32,
so no need EARLYCON_DECLARE.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1576822230-23125-2-git-send-email-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty/serial: Migrate fsl_lpuart to use has_sysrq

The SUPPORT_SYSRQ ifdeffery is not nice as:
- May create misunderstanding about sizeof(struct uart_port) between
different objects
- Prevents moving functions from serial_core.h
- Reduces readability (well, it's ifdeffery - it's hard to follow)

In order to remove SUPPORT_SYSRQ, has_sysrq variable has been added.
Initialise it in driver's probe and remove ifdeffery.

Signed-off-by: Dmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20191213000657.931618-19-dima@arista.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: use the sg count from dma_map_sg

The dmaengine_prep_slave_sg needs to use sg count returned
by dma_map_sg, not use sport->dma_tx_nents, because the return
value of dma_map_sg is not always same with "nents".

When enabling iommu for lpuart + edma, iommu framework may concatenate
two sgs into one.

Fixes: 6250cc30c4c4e ("tty: serial: fsl_lpuart: Use scatter/gather DMA for Tx")
Cc: <stable@vger.kernel.org>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1572932977-17866-1-git-send-email-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: Add RS485 support for 32-bit uart flavour

This commits adds RS485 support for LPUART hardware that uses 32-bit
registers. These are typically found in i.MX8 processors.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>

Link: https://lore.kernel.org/r/20191017141428.10330-3-philippe.schenker@toradex.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: Use defines that correspond to correct register

Use define from the 32-bit register description UARTMODIR_* instead of
UARTMODEM_*. The value is the same, so there is no functional change.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Reviewed-by: Stefan Agner <stefan.agner@toradex.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>

Link: https://lore.kernel.org/r/20191017141428.10330-2-philippe.schenker@toradex.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: Remove unnecessary code from set_mctrl

Currently flow control is not working due to lpuart32_set_mctrl that is
clearing TXCTSE bit in all cases. This bit gets earlier setup by
lpuart32_set_termios.

As I read in Documentation set_mctrl is also not meant for hardware
flow control rather than gpio setting and clearing a RTS signal.
Therefore I guess it is safe to remove the whole code in
lpuart32_set_mctrl.

This was tested with console on a i.MX8QXP SoC.

Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Reviewed-by: Fugang Duan <fugang.duan@nxp.com>

Link: https://lore.kernel.org/r/20191017141428.10330-1-philippe.schenker@toradex.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Fix lpuart_flush_buffer()

Fix incorrect read-modify-write sequence in lpuart_flush_buffer() that
was reading from UARTPFIFO and writing to UARTCFIFO instead of
operating solely on the latter.

Fixes: 9bc19af9dacb ("tty: serial: fsl_lpuart: Flush HW FIFOs in .flush_buffer")
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reported-by: Vivien Didelot <vivien.didelot@gmail.com>
Tested-by: Vivien Didelot <vivien.didelot@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Jiri Slaby <jslaby@suse.com>
Link: https://lore.kernel.org/r/20191004215537.5308-1-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Ignore TX/RX interrupts if DMA is enabled

In a mixed DMA/IRQ use-case (e.g.: DMA for TX, IRQ for RX), interrupt
handler might try to handle Rx/Tx condition it shouldn't. Change the
code to only handle TX/RX event if corresponding path isn't being
handled by DMA.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-7-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Don't enable TIE in .startup() or .resume()

Enabling TIE in .startup() callback causes the driver to start (or at
least try) to transmit data before .start_tx() is called. Which, while
harmless (since TIE handler will immediately disable it), is a no-op
and shouldn't really happen. Drop UARTCR2_TIE from list of bits set in
lpuart_startup().

This change will also not enable TIE in .resume(), but it seems that,
similart to .startup(), transmit interrupt shouldn't be enabled there
either.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-6-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Introduce lpuart*_setup_watermark_enable()

Most users of lpuart*_setup_watermark() enable identical set of flags
right after the call, so combine those two action into a subroutine
and make use of it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-5-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Introduce lpuart32_configure()

Code doing final steps of TX/RX configuration in lpuart32_startup()
and lpuart_resume() is identical, so move it into a standalone
subroutine.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-4-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Introduce lpuart_rx_dma_startup()

Code doing initial DMA RX configuration in lpuart_startup() and
lpuart32_startup() is exactly the same, so move it into a standalone
subroutine.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-3-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Introduce lpuart_tx_dma_startup()

Code configure DMA TX path in lpuart_startup(), lpuart32_startup() and
lpuart_resume() is doing exactly the same thing, so move it into a
standalone subroutine.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-2-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: Remove dev_err() usage after platform_get_irq()

We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.

// <smpl>
@@
expression ret;
struct platform_device *E;
@@

ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);

if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>

While we're here, remove braces on if statements that only have one
statement (manually).

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-45-swboyd@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Introduce lpuart_dma_shutdown()

Last steps of .shutdown() code are identical for lpuart and lpuart32
cases, so move it all into a standalone subroutine.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-19-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Drop unnecessary lpuart*_stop_tx()

By the time lpuart_shutdown() calls lpuart_stop_tx() UARTCR2_TE and
UARTCR2_TIE (which the latter will clear) are already cleared, so that
function call should effectively be a no-op. Moreso, lpuart_stop_tx()
is expected to be executed with port spinlock held, which the caller
doesn't. Given all that, drop the call to lpuart_stop_tx() in
lpuart_shutdown().

In case of lpuart32_shutdown()/lpuart32_stop_tx(), TIE won't even be
set if lpuart_dma_tx_use is true. Drop it there as well.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-18-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Introduce lpuart_stopped_or_empty()

The check for

uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)

appears in multiple places in the driver. Move it into a helper
function.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-17-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Use cpu_relax() instead of barrier()

Use cpu_relax() instead of barrier() in a tight polling loops to make
them a bit more idiomatic. Should also improve things on ARM64 a bit
since cpu_relax() will expand into "yield" instruction there.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-16-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Introduce lpuart_wait_bit_set()

Busy polling on a bit in a register is used in multiple places in the
driver. Move it into a shared function.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-15-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Use appropriate lpuart32_* I/O funcs

When dealing with 32-bit variant of LPUART IP block appropriate I/O
helpers have to be used to properly deal with endianness
differences. Change all of the offending code to do that.

Fixes: a5fa2660d787 ("tty/serial/fsl_lpuart: Add CONSOLE_POLL support
for lpuart32.")
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-14-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Clear CSTOPB unconditionally

Clearing CSTOPB bit if it is set is functionally equivalent to jsut
clearing it unconditionally. Drop unnecessary check.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-13-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Drop unnecessary extra parenthesis

Drop unnecessary extra parenthesis in the driver.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-12-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Drop no-op bit opearation

The check for termios->c_cflag & CRTSCTS ensure that if we reach else
branch, CRTSCTS in termios->c_cflag is already going to be
cleard. Doing so explicitly there is not necessary. Drop it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-11-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fls_lpuart: Split shared TX IRQ handler into two

While sharing code for Tx interrupt handler between 8 and 32 bit
variant of the peripheral saves a bit of code duplication it also adds
quite a number of lpuart_is_32() checks which makes it harder to
understand. Move shared bits back into corresponding
lpuart*_transmit_buffer functions, split lpuart_txint into
lpuart_txint and lpuart32_txint so we can drop all extra
lpuart_is_32() check and make the code flow more linear.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-10-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Fix issue in software flow control

Although I haven't observed this bug in practice, it seems that the
code for handling x_char of LPUART is pretty much identical to that of
i.MX. So the fix found in commit 7e2fb5aa8d81 ("serial: imx: Fix issue
in software flow control"):

serial: imx: Fix issue in software flow control

After send out x_char in UART driver, x_char needs to be cleared
by UART driver itself, otherwise data in TXFIFO can no longer be
sent out.
Also tx counter needs to be increased to keep track of correct
number of transmitted data.

Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

should apply here as well.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-9-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Drop unnecessary uart_write_wakeup()

Uart_write_wakeup() will already be called as a part of
lpuart*_transmit_buffer() call, so there doesn't seem to be a reason
to call it again right after.

It also appears that second uart_write_wakeup() might potentially
cause unwanted write wakeup when transmitting an x_char. See commit
5e42e9a30cda ("serial: imx: Fix x_char handling and tx flow control")
where this problem was fixed in a very similarly structured i.MX UART
driver.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-8-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Fix bogus indentation

Fix bogus indentation in rx_dma_timer_init().

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-6-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Simplify RX/TX IRQ handlers

It appears that lpuart_rxint, lpuart_txint and lpuart32_rxint were
modelled after identical function found in UART driver for
i.MX. However, while said functions are used as individual IRQ
handlers in i.MX driver (in case of i.MX1), it is not the case for
LPUART. Given that, there's no need for us to restrict the prototype
of the handler to irqreturn_t foo(int, void *) and we can drop all of
uneened boilerplate code by changing it void foo(struct lpuart_port *).

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-5-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Flush HW FIFOs in .flush_buffer

Switching baud rate might cause bogus data to appear in HW
FIFO. Add code to do a HW FIFO flush to .flush_buffer callback to
avoid that.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-4-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: flush receive FIFO after overruns

After overruns the FIFO pointers become misaligned. This
typically shows by characters still being stuck in the FIFO
despite the empty flag being asserted. After the first
assertion of the overrun flag the empty flag still seems to
indicate FIFO state correctly and all data can be read.
However, after another overrun assertion the FIFO seems to
be off by one such that the last received character is still
in the FIFO (despite the empty flag being asserted).

Flushing the receive FIFO reinitializes pointers. Hence it
is recommended to flush the FIFO after overruns, see also:
https://community.nxp.com/thread/321175

Hence, on assertion of the overrun flag read the remaining
data from the FIFO and flush buffers.

Signed-off-by: Stefan Agner <stefan.agner@toradex.com>
Acked-by: Max Krummenacher <max.krummenacher@toradex.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-3-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix framing error handling when using DMA

When using DMA framing error get cleared properly. However, due
to the additional read from the data register, an underflow in
the receive FIFO buffer occurs (the FIFO pointer gets out of
sync).

Clear the FIFO in case an underflow has occurred. Also disable the
receiver during this operation and when reading the data register to
minimize potential interference.

Signed-off-by: Stefan Agner <stefan.agner@toradex.com>
Acked-by: Max Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-2-andrew.smirnov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: correct the FIFO depth size

VF610/LS1021a/i.MX7ULP/i.MX8QXP reference manual describe the
TXFIFOSIZE/RXFIFOSIZE field as below.

000b - FIFO/Buffer depth = 1 dataword.
001b - FIFO/Buffer depth = 4 datawords.
010b - FIFO/Buffer depth = 8 datawords.
011b - FIFO/Buffer depth = 16 datawords.
100b - FIFO/Buffer depth = 32 datawords.
101b - FIFO/Buffer depth = 64 datawords.
110b - FIFO/Buffer depth = 128 datawords.
111b - FIFO/Buffer depth = 256 datawords. (Reserved for VF610)

So the FIFO depth should be: 0x1 << (val ? (val + 1) : 0)

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-6-fugang.duan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: remove sg_set_buf() for sport->rx_sgl

Since .sg_init_one() already set sg entry page like below code.
sg_init_one()
sg_init_table(sg, 1);
sg_set_buf(sg, buf, buflen);

So it should not set sg entry page again, remove the redundant code.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-5-fugang.duan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: use kzalloc() instead of kmalloc()

Use kzalloc() instead of kmalloc() to get clean rx buffer
that is useful for DMA mode debug to check the data moving
validity.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-4-fugang.duan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: add earlycon for imx8qxp platform

Add earlycon support for imx8qxp platform.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-3-fugang.duan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: remove the dev.coherent_dma_mask zero setting

By default, .of_dma_configure() init dev.coherent_dma_mask to BIT(32) that
match the eDMA address range. If re-init dev.coherent_dma_mask to zero, then
streaming dma mapping will go swiotlb dma_map, if swiotlb is not initalized
then it causes mapping failed.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-2-fugang.duan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: add imx8qxp support

The lpuart of imx8ulp is basically the same as imx7ulp, but it
has new feature support based on imx7ulp, like it can assert a
DMA request on EOP(end-of-packet). imx8ulp lpuart use two clocks,
one is ipg bus clock that is used to access registers, the other
is baud clock that is used to transmit-receive data.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190704134007.2316-1-fugang.duan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Remove unneeded OOM error message

There is no need to add an out-of-memory error message inside
the driver because the core MM code will take care of it.

Remove the unneeded OOM error message.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Use dev_info() instead of printk()

dev_info() is more appropriate for printing messages inside drivers, so
switch to dev_info().

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: DMA support for 32-bit variant

Add DMA support for 32-bit variant of the LPUART, such as LS1021A.

Signed-off-by: Tomonori Sakita <tomonori.sakita@sord.co.jp>
Signed-off-by: Atsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: consider TX FIFO too in lpuart32_tx_empty

The commit 3876a00fcb6b ("tty: serial: fsl_lpuart: consider TX FIFO
too in tx_empty") fixed lpuart_tx_empty only.
Fix lpuart32_tx_empty too.

Signed-off-by: Atsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: specify transmit FIFO size for 32-bit variant

The commit 4e8f24593709 ("tty: serial: fsl_lpuart: specify transmit
FIFO size") fixed lpuart_startup only.
Fix lpuart32_startup too.

Signed-off-by: Atsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: fix maximum acceptable baud rate with over-sampling

Using over-sampling ratio, lpuart can accept baud rate upto uartclk / 4.

Signed-off-by: Tomonori Sakita <tomonori.sakita@sord.co.jp>
Signed-off-by: Atsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: clear parity enable bit when disable parity

Current driver only enable parity enable bit and never clear it
when user set the termios. The fix clear the parity enable bit when
PARENB flag is not set in termios->c_cflag.

Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Andy Duan <fugang.duan@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: fix the typo: UARTCR1_PE -> UARTCTRL_PE

Fix the typo: UARTCR1_PE -> UARTCTRL_PE
There have no function impacted since the macro define value is
the same.

Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Andy Duan <fugang.duan@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Remove the alias node dependence

Numbering the ttyLPn space should not depend on the generic name
"serial<n>".

If don't add the alias node like:"serial0 = &lpuart0;", then lpuart
will probe failed:
[ 0.773410] fsl-lpuart 2950000.serial: failed to get alias id, errno -19

So remove the alias node dependence, and add the support for allocate the
line port automatically.

Signed-off-by: Yuan Yao <yao.yuan@nxp.com>
Signed-off-by: Vabhav Sharma <vabhav.sharma@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: avoid leaking struct tty_struct

The function tty_port_tty_get() gets a reference to the tty. Since
the code is not using tty_port_tty_set(), the reference is kept
even after closing the tty.

Avoid using tty_port_tty_get() by directly access the tty instance.
Since lpuart_start_rx_dma() is called from the .startup() and
.set_termios() callback, it is safe to assume the tty instance is
valid.

Cc: stable@vger.kernel.org # v4.9+
Fixes: 5887ad43ee02 ("tty: serial: fsl_lpuart: Use cyclic DMA for Rx")
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Fix out-of-bounds access through DT alias

The lpuart_ports[] array is indexed using a value derived from the
"serialN" alias in DT, which may lead to an out-of-bounds access.

Fix this by adding a range check.

Fixes: c9e2e946fb0ba5d2 ("tty: serial: add Freescale lpuart driver support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Support common rs485 binding for RTS polarity

Invoke the ->rs485_config callback on probe to set UARTMODEM_TXRTSPOL
appropriately based on the UART's device properties.

This implicitly sets UARTMODEM_TXRTSE if rs485 was enabled in the device
properties, so drop the identical code from lpuart_probe().

It also fixes a bug: If an unsupported rs485 property was specified
(rs485-rx-during-tx or rs485-rts-delay), the driver returns -ENOSYS
without performing any cleanup, in particular without calling
uart_remove_one_port() or clk_disable_unprepare(), thus leaking the
uart_port. But with the invocation of ->rs485_config, the unsupported
properties are now cleared in struct serial_rs485 and thus ignored.
It therefore seems sufficient to just log an error instead of bailing
out.

Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Make retrieval of rs485 properties platform-agnostic

Commit ef838a81dd4d ("serial: Add common rs485 device tree parsing
function") consolidated retrieval of rs485 OF properties in a common
helper function but did not #ifdef it to CONFIG_OF. The function is
therefore included on ACPI platforms as well even though it's not used.

On the other hand ACPI platforms with rs485 do exist (e.g. Siemens
IOT2040) and they may leverage _DSD to store rs485 properties. Likewise,
UART platform devices instantiated from an MFD should be able to specify
rs485 properties. In fact, the tty subsystem maintainer had asked for
a "generic" function during review of commit ef838a81dd4d:
https://marc.info/?l=linux-serial&m=150143441725194&w=4

Thus, instead of constraining the helper to OF platforms, make it
platform-agnostic by converting it to device_property_*() functions
and renaming it accordingly.

In imx.c, move the invocation of uart_get_rs485_mode() from
serial_imx_probe_dt() to serial_imx_probe() so that it also gets called
for non-OF devices.

In omap-serial.c, move its invocation further up within
serial_omap_probe_rs485() so that the RTS polarity can be overridden
with the driver-specific "rs485-rts-active-high" property once we
introduce a generic "rs485-rts-active-low" property.

Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

treewide: setup_timer() -> timer_setup()

This converts all remaining cases of the old setup_timer() API into using
timer_setup(), where the callback argument is the structure already
holding the struct timer_list. These should have no behavioral changes,
since they just change which pointer is passed into the callback with
the same available pointers after conversion. It handles the following
examples, in addition to some other variations.

Casting from unsigned long:

void my_callback(unsigned long data)
{
struct something *ptr = (struct something *)data;
...
}
...
setup_timer(&ptr->my_timer, my_callback, ptr);

and forced object casts:

void my_callback(struct something *ptr)
{
...
}
...
setup_timer(&ptr->my_timer, my_callback, (unsigned long)ptr);

become:

void my_callback(struct timer_list *t)
{
struct something *ptr = from_timer(ptr, t, my_timer);
...
}
...
timer_setup(&ptr->my_timer, my_callback, 0);

Direct function assignments:

void my_callback(unsigned long data)
{
struct something *ptr = (struct something *)data;
...
}
...
ptr->my_timer.function = my_callback;

have a temporary cast added, along with converting the args:

void my_callback(struct timer_list *t)
{
struct something *ptr = from_timer(ptr, t, my_timer);
...
}
...
ptr->my_timer.function = (TIMER_FUNC_TYPE)my_callback;

And finally, callbacks without a data assignment:

void my_callback(unsigned long data)
{
...
}
...
setup_timer(&ptr->my_timer, my_callback, 0);

have their argument renamed to verify they're unused during conversion:

void my_callback(struct timer_list *unused)
{
...
}
...
timer_setup(&ptr->my_timer, my_callback, 0);

The conversion is done with the following Coccinelle script:

spatch --very-quiet --all-includes --include-headers \
-I ./arch/x86/include -I ./arch/x86/include/generated \
-I ./include -I ./arch/x86/include/uapi \
-I ./arch/x86/include/generated/uapi -I ./include/uapi \
-I ./include/generated/uapi --include ./include/linux/kconfig.h \
--dir . \
--cocci-file ~/src/data/timer_setup.cocci

@fix_address_of@
expression e;
@@

setup_timer(
-&(e)
+&e
, ...)

// Update any raw setup_timer() usages that have a NULL callback, but
// would otherwise match change_timer_function_usage, since the latter
// will update all function assignments done in the face of a NULL
// function initialization in setup_timer().
@change_timer_function_usage_NULL@
expression _E;
identifier _timer;
type _cast_data;
@@

(
-setup_timer(&_E->_timer, NULL, _E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E->_timer, NULL, (_cast_data)_E);
+timer_setup(&_E->_timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, &_E);
+timer_setup(&_E._timer, NULL, 0);
|
-setup_timer(&_E._timer, NULL, (_cast_data)&_E);
+timer_setup(&_E._timer, NULL, 0);
)

@change_timer_function_usage@
expression _E;
identifier _timer;
struct timer_list _stl;
identifier _callback;
type _cast_func, _cast_data;
@@

(
-setup_timer(&_E->_timer, _callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, &_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, _E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, &_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)_E);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, (_cast_func)&_callback, (_cast_data)&_E);
+timer_setup(&_E._timer, _callback, 0);
|
_E->_timer@_stl.function = _callback;
|
_E->_timer@_stl.function = &_callback;
|
_E->_timer@_stl.function = (_cast_func)_callback;
|
_E->_timer@_stl.function = (_cast_func)&_callback;
|
_E._timer@_stl.function = _callback;
|
_E._timer@_stl.function = &_callback;
|
_E._timer@_stl.function = (_cast_func)_callback;
|
_E._timer@_stl.function = (_cast_func)&_callback;
)

// callback(unsigned long arg)
@change_callback_handle_cast
depends on change_timer_function_usage@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
identifier _handle;
@@

void _callback(
-_origtype _origarg
+struct timer_list *t
)
{
(
... when != _origarg
_handletype *_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
|
... when != _origarg
_handletype *_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
|
... when != _origarg
_handletype *_handle;
... when != _handle
_handle =
-(_handletype *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
|
... when != _origarg
_handletype *_handle;
... when != _handle
_handle =
-(void *)_origarg;
+from_timer(_handle, t, _timer);
... when != _origarg
)
}

// callback(unsigned long arg) without existing variable
@change_callback_handle_cast_no_arg
depends on change_timer_function_usage &&
!change_callback_handle_cast@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _origtype;
identifier _origarg;
type _handletype;
@@

void _callback(
-_origtype _origarg
+struct timer_list *t
)
{
+ _handletype *_origarg = from_timer(_origarg, t, _timer);
+
... when != _origarg
- (_handletype *)_origarg
+ _origarg
... when != _origarg
}

// Avoid already converted callbacks.
@match_callback_converted
depends on change_timer_function_usage &&
!change_callback_handle_cast &&
!change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier t;
@@

void _callback(struct timer_list *t)
{ ... }

// callback(struct something *handle)
@change_callback_handle_arg
depends on change_timer_function_usage &&
!match_callback_converted &&
!change_callback_handle_cast &&
!change_callback_handle_cast_no_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
@@

void _callback(
-_handletype *_handle
+struct timer_list *t
)
{
+ _handletype *_handle = from_timer(_handle, t, _timer);
...
}

// If change_callback_handle_arg ran on an empty function, remove
// the added handler.
@unchange_callback_handle_arg
depends on change_timer_function_usage &&
change_callback_handle_arg@
identifier change_timer_function_usage._callback;
identifier change_timer_function_usage._timer;
type _handletype;
identifier _handle;
identifier t;
@@

void _callback(struct timer_list *t)
{
- _handletype *_handle = from_timer(_handle, t, _timer);
}

// We only want to refactor the setup_timer() data argument if we've found
// the matching callback. This undoes changes in change_timer_function_usage.
@unchange_timer_function_usage
depends on change_timer_function_usage &&
!change_callback_handle_cast &&
!change_callback_handle_cast_no_arg &&
!change_callback_handle_arg@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type change_timer_function_usage._cast_data;
@@

(
-timer_setup(&_E->_timer, _callback, 0);
+setup_timer(&_E->_timer, _callback, (_cast_data)_E);
|
-timer_setup(&_E._timer, _callback, 0);
+setup_timer(&_E._timer, _callback, (_cast_data)&_E);
)

// If we fixed a callback from a .function assignment, fix the
// assignment cast now.
@change_timer_function_assignment
depends on change_timer_function_usage &&
(change_callback_handle_cast ||
change_callback_handle_cast_no_arg ||
change_callback_handle_arg)@
expression change_timer_function_usage._E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_func;
typedef TIMER_FUNC_TYPE;
@@

(
_E->_timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E->_timer.function =
-&_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E->_timer.function =
-(_cast_func)_callback;
+(TIMER_FUNC_TYPE)_callback
;
|
_E->_timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-&_callback;
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-(_cast_func)_callback
+(TIMER_FUNC_TYPE)_callback
;
|
_E._timer.function =
-(_cast_func)&_callback
+(TIMER_FUNC_TYPE)_callback
;
)

// Sometimes timer functions are called directly. Replace matched args.
@change_timer_function_calls
depends on change_timer_function_usage &&
(change_callback_handle_cast ||
change_callback_handle_cast_no_arg ||
change_callback_handle_arg)@
expression _E;
identifier change_timer_function_usage._timer;
identifier change_timer_function_usage._callback;
type _cast_data;
@@

_callback(
(
-(_cast_data)_E
+&_E->_timer
|
-(_cast_data)&_E
+&_E._timer
|
-_E
+&_E->_timer
)
)

// If a timer has been configured without a data argument, it can be
// converted without regard to the callback argument, since it is unused.
@match_timer_function_unused_data@
expression _E;
identifier _timer;
identifier _callback;
@@

(
-setup_timer(&_E->_timer, _callback, 0);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0L);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E->_timer, _callback, 0UL);
+timer_setup(&_E->_timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0L);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_E._timer, _callback, 0UL);
+timer_setup(&_E._timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0L);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(&_timer, _callback, 0UL);
+timer_setup(&_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0L);
+timer_setup(_timer, _callback, 0);
|
-setup_timer(_timer, _callback, 0UL);
+timer_setup(_timer, _callback, 0);
)

@change_callback_unused_data
depends on match_timer_function_unused_data@
identifier match_timer_function_unused_data._callback;
type _origtype;
identifier _origarg;
@@

void _callback(
-_origtype _origarg
+struct timer_list *unused
)
{
... when != _origarg
}

Signed-off-by: Kees Cook <keescook@chromium.org>

tty: serial: Remove redundant license text

Now that the SPDX tag is in all tty files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Jiri Slaby <jslaby@suse.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: add SPDX identifiers to all remaining files in drivers/tty/

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/tty files files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Jiri Slaby <jslaby@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: "Uwe Kleine-König" <kernel@pengutronix.de>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Use common rs485 device tree parsing function

We just got a common helper for parsing the rs485 specific
device tree properties. Use it and drop the open coded parser.

As a side effect this adds support for parsing rs485-rts-delay and
rs485-rx-during-tx. As the driver doesn't support this though, probing
fails if these are defined.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Remove unused 'bd' variable

Since commit a6d7514b14a6 ("tty: serial: lpuart: add a more accurate baud
rate calculation method") the baud rate is now calculated inside the
lpuart32_serial_setbrg() function, so we no longer need to read the
UARTBAUD register inside lpuart32_set_termios().

The 'bd' variable can be simply removed.

This fixes the following build warning with W=1:

drivers/tty/serial/fsl_lpuart.c: In function 'lpuart32_set_termios':
drivers/tty/serial/fsl_lpuart.c:1652:32: warning: variable 'bd' set but not used [-Wunused-but-set-variable]

Fixes: a6d7514b14a6 ("tty: serial: lpuart: add a more accurate baud rate calculation method")
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: avoid report NULL interrupt

The current driver register irq in .startup() and free the irq in
.shutdown(), then user will see the NULL interrupt output from
'cat /proc/interrupts' after the uart port test completed:
...
41: 515 0 0 0 GICv3 257 Level fsl-lpuart
42: 2 0 0 0 GICv3 258 Level
...

It is better to register all the irqs during probe function via devm_request_irq()
to avoid to call free_irq().

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Avoid using irq_wake flag

There is no need to duplicate a flag which IRQ core takes care of.

Replace custom flag by IRQ core API that retrieves its state.

Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: clear unsupported options in .rs485_config()

The struct serial_rs485 parameter is both input and output and is
supposed to hold the actually used configuration on return. So clear
unsupported settings.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty/serial/fsl_lpuart: Add CONSOLE_POLL support for lpuart32.

This mirrors commit 2a41bc2a2b but for 32-bit register definitions.

Fix a minor typo while at it.

Signed-off-by: Marius Vlad <marius.vlad0@gmail.com>
CC: Nicolae Rosia <nicolae_rosia@mentor.com>
CC: Stefan Golinschi <stefan.golinschi@gmail.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: Fix the logic for detecting the 32-bit type UART

Commit 0d6fce904452 ("tty: serial: lpuart: introduce lpuart_soc_data to
represent SoC property") introduced a buggy logic for detecting the 32-bit
type UART since the condition: "if (sport->port.iotype & UPIO_MEM32BE)"
is always true.

Performing such bitfield AND operation is not correct, because in the
case of Vybrid UART iotype is UPIO_MEM (2), so:

UPIO_MEM & UPIO_MEM32BE = 010 & 110 = 010, which is true.

Such logic tells the driver to always treat the UART operations as 32-bit,
leading to the driver misbehavior on Vybrid.

Fix the 32-bit type detection logic to avoid UART breakage on Vybrid.

While at it, introduce a lpuart_is_32() function to help readability.

Fixes: 0d6fce904452 ("tty: serial: lpuart: introduce lpuart_soc_data to represent SoC property")
Reported-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Tested-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: add a more accurate baud rate calculation method

On new LPUART versions, the oversampling ratio for the receiver can be
changed from 4x (00011) to 32x (11111) which could help us get a more
accurate baud rate divider.

The idea is to use the best OSR (over-sampling rate) possible.
Note, OSR is typically hard-set to 16 in other LPUART instantiations.
Loop to find the best OSR value possible, one that generates minimum
baud diff iterate through the rest of the supported values of OSR.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Mingkai Hu <Mingkai.Hu@nxp.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: add earlycon support for imx7ulp

earlycon is executed quite early before the device tree probe,
so we need correctly initialize the port membase and iotype for
imx7ulp during early console setup before using.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Mingkai Hu <Mingkai.Hu@nxp.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: add imx7ulp support

The lpuart of imx7ulp is basically the same as ls1021a. It's also
32 bit width register, but unlike ls1021a, it's little endian.
Besides that, imx7ulp lpuart has a minor different register layout
from ls1021a that it has four extra registers (verid, param, global,
pincfg) located at the beginning of register map, which are currently
not used by the driver and less to be used later.

To ease the register difference handling, we add a reg_off member
in lpuart_soc_data structure to represent if the normal
lpuart32_{read|write} requires plus a offset to hide the issue.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Mingkai Hu <Mingkai.Hu@nxp.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Cc: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: add little endian 32 bit register support

Use standard port->iotype to distinguish endian difference. Note as we
read/write register by checking iotype dynamically, we need to initialize
the iotype correctly for earlycon as well to avoid a break.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com> (supporter:TTY LAYER)
Cc: Stefan Agner <stefan@agner.ch>
Cc: Mingkai Hu <Mingkai.Hu@nxp.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Cc: Fugang Duan <fugang.duan@nxp.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>

ChangeLog:
v3->v4:
* Removed unneeded semicolon catched by 0day Robot.
v2->v3:
* Instead of using global var, use standard port->iotype to distinguish
endian difference.
v1->v2:
* No changes
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: refactor lpuart32_{read|write} prototype

Due to the original lpuart32_read/write takes no port specific
information arguments, it's hard to distinguish port difference
within the API. Although it works before, but not suitable anymore
when adding more new chips support.

So let's convert it to accept a new struct uart_port argument
to make it be able to retrieve more port specific information.
This is a preparation for the later adding new chips support
more easily. No functions changes.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Mingkai Hu <Mingkai.Hu@nxp.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Cc: Fugang Duan <fugang.duan@nxp.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: lpuart: introduce lpuart_soc_data to represent SoC property

This is used to dynamically check the SoC specific lpuart properies.
Currently only the iotype is added, it functions the same as before.
With this, new chips with different iotype will be more easily added.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Mingkai Hu <Mingkai.Hu@nxp.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Cc: Fugang Duan <fugang.duan@nxp.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: lock port on console write

The console write code is not entirely race free (e.g. the operations
to disabling the UART interrupts are not atomic) hence locking is
required. This has been become apparent with the PREEMPT RT patchset
applied: With the fully preemptible kernel configuration the system
often ended up in a freeze already at startup.

Disable interrupts and lock using read_lock_irqsave. Try to lock in
the sysrq/oops case, but don't bother if locking fails.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix del_timer_sync() vs timer routine deadlock

Problem found via lockdep:

- lpuart_set_termios() calls del_timer_sync(&sport->lpuart_timer) while
holding sport->port.lock

- sport->lpuart_timer routine is lpuart_timer_func() that calls
lpuart_copy_rx_to_tty() that acquires same lock.

To fix, move Rx DMA stopping out of lock, as it already is in other places
in the same file.

While at it, also make Rx DMA start/stop code to look the same is in
other places in the same file.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Tested-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: remove build warning

commit 2a41bc2a2b05 ("tty: serial: fsl_lpuart: add polled console
functions") caused a build warning about an unused variable, so fix it.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Cc: Nicolae Rosia <nicolae_rosia@mentor.com>
Cc: Stefan Golinschi <stefan.golinschi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Fix Tx DMA edge case

In the case where head == 0 on the circular buffer, there should be one
DMA buffer, not two. The second zero-length buffer would break the
lpuart driver, transfer would never complete.

Signed-off-by: Aaron Brice <aaron.brice@datasoft.com>
Acked-by: Stefan Agner <stefan@agner.ch>
Tested-by: Stefan Agner <stefan@agner.ch>
Tested-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: add polled console functions

This adds polling functions as used by kgdb.

Signed-off-by: Nicolae Rosia <nicolae_rosia@mentor.com>
Signed-off-by: Stefan Golinschi <stefan.golinschi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: use GFP_ATOMIC under spin lock

The function lpuart_start_rx_dma() is called from several
places, in some of which, such as lpuart_startup(), a lock
be held here, so we should use GFP_ATOMIC when a lock is held.

Fixes: 5887ad43ee02 ("tty: serial: fsl_lpuart: Use cyclic DMA for Rx")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: constify uart_ops structures

Check for uart_ops structures that are only stored in the ops field of a
uart_port structure. This field is declared const, so uart_ops structures
that have this property can be declared as const also.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct uart_ops i@p = { ... };

@ok@
identifier r.i;
struct uart_port e;
position p;
@@
e.ops = &i@p;

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct uart_ops e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
struct uart_ops i = { ... };
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Add support for RS-485

Enable Vybrid's build-in support for RS-485 auto RTS for controlling line
direction of RS-485 transceiver driver.

Enable RS485 feature by either using ioctrl 'TIOCSRS485' or enable it in the
device tree by setting 'linux,rs485-enabled-at-boot-time' property.

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Update suspend/resume for DMA mode

When DMA mode is enabled one need to make sure the DMA channels are idle before
entering suspend mode especially when UART ports which are set as wakeup source
and console port with no_console_suspend is set. This patch takes care of
gracefully releasing DMA channels for the above two cases and start the DMA at
resume.

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Use scatter/gather DMA for Tx

Drop PIO to DMA switching and use scatter/gather DMA for Tx path to improve
performance.

Some part of the code is borrowed from imx serial driver.

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Use cyclic DMA for Rx

The initial approach of DMA implementatin for RX is inefficient due to switching
from PIO to DMA, this leads to overruns especially on instances with the smaller
FIFO. To address these issues this patch uses a cyclic DMA for receiver path.

Some part of the code is borrowed from atmel serial driver.

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: Fix broken 8m/s1 support

By default the driver always configure the mode as 8s1 even when 8m1 mode is
selected. Fix this by adding support to control the space/mark bit.

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: fix clearing of receive flag

Commit 8e4934c6d6c6 ("tty: serial: fsl_lpuart: clear receive flag on FIFO
flush") implemented clearing of the receive flag by reading the status register
only. It turned out that even though we flush the FIFO afterwards, a explicit
read of the data register is still required.

This leads to a FIFO underrun. To avoid this, follow the advice in the overrun
"Operation section": Unconditionally clear RXUF after using RXFLUSH.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: support suspend/resume

Add suspend/resume support.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: consider TX FIFO too in tx_empty

Currently the tx_empty callback only considers the Transmit Complete Flag (TC).
The reference manual is not quite clear if the TC flag covers the TX FIFO too.
Debug prints on real hardware have shown that from time to time the TC flag is
asserted (indicating Transmitter idle) while there are still data in the
TX FIFO. Hence, in this case the serial core will call the shutdown callback
even though there are data remaining in the TX FIFO buffers.

Avoid early shutdowns by considering the TX FIFO empty flag too. Also avoid
theoretical race conditions between DMA and the driver by checking whether the
TX DMA is in progress too.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

TTY: serial, handle platform_get_irq retval properly

platform_get_irq can fail, so we should handle negative value when
returned.

[v2]

platform_get_irq can actually return zero on some platforms. So do not
remove checks for irq == 0 there.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "Uwe Kleine-König" <kernel@pengutronix.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: add earlycon support

Add support for DT and command line based earlycon support for
lpuart and lpuart32 used on Freescale Vybrid and and QorIQ LS1021A
processors.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: clear receive flag on FIFO flush

When the receiver was enabled during startup, a character could
have been in the FIFO when the UART get initially used. The
driver configures the (receive) watermark level, and flushes the
FIFO. However, the receive flag (RDRF) could still be set at that
stage (as mentioned in the register description of UARTx_RWFIFO).
This leads to an interrupt which won't be handled properly in
interrupt mode: The receive interrupt function lpuart_rxint checks
the FIFO count, which is 0 at that point (due to the flush
during initialization). The problem does not manifest when using
DMA to receive characters.

Fix this situation by explicitly read the status register, which
leads to clearing of the RDRF flag. Due to the flush just after
the status flag read, a explicit data read is not to required.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: specify transmit FIFO size

Specify transmit FIFO size which might be different depending on
LPUART instance. This makes sure uart_wait_until_sent in serial
core getting called, which in turn waits and checks if the FIFO
is really empty on shutdown by using the tx_empty callback.
Without the call of this callback, the last several characters
might not yet be transmitted when closing the serial port. This
can be reproduced by simply using echo and redirect the output to
a ttyLP device.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: constify of_device_id array

of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Acked-by: Peter Korsgaard <peter@korsgaard.com>
Acked-by: Timur Tabi <timur@tabi.org>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: fsl_lpuart: terminate DMA on buffer flush

On uart buffer flush, serial core resets the circular buffer.
If a DMA transfer is in progress at that time, the callback
lpuart_dma_tx_complete will move buffer's tail unconditionally,
hence tail moves beyond head. Use the flush_buffer hook to
terminate the DMA imeaditely and avoid lpuart_dma_tx_complete
being called in this situation.

This bug often showed up while shutdown and lead to duplicate
serial console output.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl-lpuart: disable interrupt when suspend

For power management support, we should disable TX and
TX interrupt so that kernel can prepare for deep sleep.

Retain RX and RX interrupt for wakeup the kernel when
receive the input character.

Signed-off-by: Yuan Yao <yao.yuan@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: update RX timer on successful DMA transfer

To end a DMA transfer which did not consume a whole buffer (e.g. one
character only), a RX timer is used. When lots of data are received
the DMA transfer will complete and setup another DMA transfer, which
in turn might complete again. In this cases, it is not necessary to
abort the DMA transfers using the RX timer. This change pushes the
RX timer timeout into the future each time a DMA transfer completed.

Aborting the DMA was not very harmful, since the next received
character lead to setup of another RX DMA.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: move DMA channel request to probe

Move the DMA channel request to probe to avoid requesting the DMA
channel on each opening of the ttyLPx device. This also fixes a
potential issue that TX channel is not freed when only RX channel
allocation fails. The DMA channels are now handled independently,
so one could use UART with DMA only in TX direction for instance.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: avoid new transfer while DMA is running

When the UART is in DMA receive mode (RDMAS set) and one character
just arrived while another interrupt is handled (e.g. TX), the RDRF
(receiver data register full flag) is set due to the water level of
1. But since the DMA will take care of this character, there is no
need to handle it by calling lpuart_prepare_rx. Handling it leads to
adding the RX timeout timer twice:

[ 74.336698] Kernel BUG at 80053070 [verbose debug info unavailable]
[ 74.342999] Internal error: Oops - BUG: 0 [#1] ARM0:00.00 khungtaskd
[ 74.347817] Modules linked in: 0 S 0.0 0.0 0:00.00 writeback
[ 74.350926] CPU: 0 PID: 0 Comm: swapper Not tainted 3.19.0-rc3-00001-g39d78e2 #1788
[ 74.358617] Hardware name: Freescale Vybrid VF610 (Device Tree)t
[ 74.364563] task: 807a7678 ti: 8079c000 task.ti: 8079c000 kblockd
[ 74.370002] PC is at add_timer+0x24/0x28.0 0.0 0:00.09 kworker/u2:1
[ 74.373960] LR is at lpuart_int+0x15c/0x3d8
[ 74.378171] pc : [<80053070>] lr : [<802e0d88>] psr: a0010193
[ 74.378171] sp : 8079de10 ip : 8079de20 fp : 8079de1c
[ 74.389694] r10: 807d44c0 r9 : 8688c300 r8 : 00000013
[ 74.394943] r7 : 20010193 r6 : 00000000 r5 : 000000a0 r4 : 86997210
[ 74.401498] r3 : ffffa7da r2 : 80817868 r1 : 86997210 r0 : 86997344
[ 74.408052] Flags: NzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
[ 74.415489] Control: 10c5387d Table: 8611c059 DAC: 00000015
[ 74.421265] Process swapper (pid: 0, stack limit = 0x8079c230)
...

Solve this by only execute the receiver path (lpuart_prepare_rx) if
the DMA receive mode (RDMAS) is not set. Also, make sure the flag is
cleared on initialization, in case it has been left set.

This can be best reproduced using UART as a serial console, then
running top while dd'ing data into the terminal.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Cc: stable <stable@vger.kernel.org> # 3.14
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: delete timer on shutdown

If the serial port gets closed while a RX transfer is in progress,
the timer might fire after the serial port shutdown finished. This
leads in a NULL pointer dereference:

[ 7.508324] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 7.516590] pgd = 86348000
[ 7.519445] [00000000] *pgd=86179831, *pte=00000000, *ppte=00000000
[ 7.526145] Internal error: Oops: 17 [#1] ARM
[ 7.530611] Modules linked in:
[ 7.533876] CPU: 0 PID: 123 Comm: systemd Not tainted 3.19.0-rc3-00004-g5b11ea7 #1778
[ 7.541827] Hardware name: Freescale Vybrid VF610 (Device Tree)
[ 7.547862] task: 861c3400 ti: 86ac8000 task.ti: 86ac8000
[ 7.553392] PC is at lpuart_timer_func+0x24/0xf8
[ 7.558127] LR is at lpuart_timer_func+0x20/0xf8
[ 7.562857] pc : [<802df99c>] lr : [<802df998>] psr: 600b0113
[ 7.562857] sp : 86ac9b90 ip : 86ac9b90 fp : 86ac9bbc
[ 7.574467] r10: 80817180 r9 : 80817b98 r8 : 80817998
[ 7.579803] r7 : 807acee0 r6 : 86989000 r5 : 00000100 r4 : 86997210
[ 7.586444] r3 : 86ac8000 r2 : 86ac9bc0 r1 : 86997210 r0 : 00000000
[ 7.593085] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[ 7.600341] Control: 10c5387d Table: 86348059 DAC: 00000015
[ 7.606203] Process systemd (pid: 123, stack limit = 0x86ac8230)

Setup the timer on UART startup which allows to delete the timer
unconditionally on shutdown. This also saves the initialization
on each transfer.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Cc: stable <stable@vger.kernel.org> # 3.14
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Remove unneeded registration message

There is no real value in displaying "serial: Freescale lpuart driver" in every
boot.

The uart_register_driver() can fail and even so the "serial: Freescale lpuart
driver" will be displayed, which is not really helpful.

This is particularly annoying when booting multi_v7_defconfig kernel on a SoC
that is not a Vybrid/Layerscape and even though this message gets displayed.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Jingchang Lu <jingchang.lu@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Remove unneeded check for 'res'

'res' will be automatically checked inside devm_ioremap_resource(), so there is
no need to explicitly perform a NULL check.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Jingchang Lu <jingchang.lu@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl-lpuart: add lpuart32 power management support

This adds 32-bit register lpuart32 power management support,
this also updates the 8-bit register lpuart resume function.

Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: drop owner assignment from platform_drivers

A platform_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

tty: serial: fsl_lpuart: add 32-bit register interface support

This add the 32-bit register version LPUART support with big-endian
byte order.

Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: calculate DMA burst

The DMA burst size must match the transmit FIFO depth in order
to make sure all character are transmitted. This patch calculates
DMA burst size by using FIFO depth rather than use the hardcoded
16 bytes. This is required since some UARTs (e.g. UART2 on Vybrid)
have a FIFO depth of 8 bytes.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: move DMA RX timeout calculation

The DMA RX timeout calculation is done based on FIFO buffer size and
port timeout when setting up DMA. However, both variables are not
necessarily initialized at DMA initialization time, which can lead
to a division by zero.

Move the timeout calculation to set_termios where both variables
are initialized.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: treewide: Remove empty implementations of enable_ms()

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: Fix IGNBRK handling

If IGNBRK is set without either BRKINT or PARMRK set, some uart
drivers send a 0x00 byte for BREAK without the TTYBREAK flag to the
line discipline, when it should send either nothing or the TTYBREAK flag
set. This happens because the read_status_mask masks out the BI
condition, which uart_insert_char() then interprets as a normal 0x00 byte.

SUS v3 is clear regarding the meaning of IGNBRK; Section 11.2.2, General
Terminal Interface - Input Modes, states:
"If IGNBRK is set, a break condition detected on input shall be ignored;
that is, not put on the input queue and therefore not read by any
process."

Fix read_status_mask to include the BI bit if IGNBRK is set; the
lsr status retains the BI bit if a BREAK is recv'd, which is
subsequently ignored in uart_insert_char() when masked with the
ignore_status_mask.

Affected drivers:
8250 - all
serial_txx9
mfd
amba-pl010
amba-pl011
atmel_serial
bfin_uart
dz
ip22zilog
max310x
mxs-auart
netx-serial
pnx8xxx_uart
pxa
sb1250-duart
sccnxp
serial_ks8695
sirfsoc_uart
st-asc
vr41xx_siu
zs
sunzilog
fsl_lpuart
sunsab
ucc_uart
bcm63xx_uart
sunsu
efm32-uart
pmac_zilog
mpsc
msm_serial
m32r_sio

Unaffected drivers:
omap-serial
rp2
sa1100
imx
icom

Annotated for fixes:
altera_uart
mcf

Drivers without break detection:
21285
xilinx-uartps
altera_jtaguart
apbuart
arc-uart
clps711x
max3100
uartlite
msm_serial_hs
nwpserial
lantiq
vt8500_serial

Unknown:
samsung
mpc52xx_uart
bfin_sport_uart
cpm_uart/core

Fixes: Bugzilla #71651, '8250_core.c incorrectly handles IGNBRK flag'
Reported-by: Ivan <athlon_@mail.ru>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: add DMA support

Add dma support for lpuart. This function depend on DMA driver.
You can turn on it by write both the dmas and dma-name properties in dts node.

Signed-off-by: Yuan Yao <yao.yuan@freescale.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: Return proper error on lpuart_serial_init error path

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: fsl_lpuart: restore UARTCR2 after watermark setup is done

Function lpuart_setup_watermark() clears some bits in register UARTCR2
before writing FIFO configuration registers as required by hardware.
But it should restore UARTCR2 after that. Otherwise, we end up changing
UARTCR2 register when setting up watermark, and that is not really
desirable. At least, when low-level debug and earlyprint is enabled,
serial console is broken due to it.

Fix the problem by restoring UARTCR2 register at the end of function
lpuart_setup_watermark().

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: add Freescale lpuart driver support

Add Freescale lpuart driver support. The lpuart device
can be found on Vybrid VF610 and Layerscape LS-1 SoCs.

Signed-off-by: Jingchang Lu <b35083@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>