tty: serial: amba: Use linux/{bits,bitfield}.h macros

The driver uses bit shifts and hexadecimal expressions to declare
constants. Replace that with the BIT(), GENMASK() & FIELD_PREP_CONST()
macros to clarify intent.

include/linux/amba/serial.h gets included from arch/arm/include/debug/pl01x.S.
Avoid includes and macro tricks for the four defines that are involved:
UART01x_DR, UART01x_FR, UART01x_FR_TXFF and UART01x_FR_BUSY.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20231207-mbly-uart-v6-1-e384afa5e78c@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: serial: amba: cleanup whitespace

Fix whitespace in include/linux/amba/serial.h to match current kernel
coding standards. Fixes about:

- CHECK: spaces preferred around that '|' (ctx:VxV)
- ERROR: code indent should use tabs where possible
- WARNING: Unnecessary space before function pointer arguments
- WARNING: please, no spaces at the start of a line

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://lore.kernel.org/r/20231130-mbly-uart-v5-1-6566703a04b5@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: amba-pl011: define flag register bits for ZTE device

For some reason we do not really understand, ZTE hardware designers
choose to define PL011 Flag Register bit positions differently from
standard ones as below.

Bit Standard ZTE
-----------------------------------
CTS 0 1
DSR 1 3
BUSY 3 8
RI 8 0

Let's define these bits into vendor data and get ZTE PL011 supported
properly.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty: amba-pl011: add support for ZTE UART (EXPERIMENTAL)

Add (incomplete) support for the ZTE UART to the AMBA PL011 driver.
This is similar to the ARM and ST variants, except it has a different
register address layout, and requires 32-bit accesses to the registers.
Use the newly introduced register tables and access size support to
cope with these differences.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "uart: pl011: Add support to ZTE ZX296702 uart"

This reverts commit 8cd90e50d1408c65c355084b1c7f8f9085f49c6b as with
this patch the serial console is broken on lots of platforms.

Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jun Nie <jun.nie@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

uart: pl011: Add support to ZTE ZX296702 uart

Support ZTE uart with some registers differing offset.
Probe as platform device for not AMBA IP ID is
available on ZTE uart.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "serial: pl011: use DMA RX polling by default"

This reverts commit 17438217a6f5e33d920ed3821a4b857311cc2872 on request
of Linus Walleij:
Greg can you please drop or revert
commit 17438217a6f5e33d920ed3821a4b857311cc2872
"serial: pl011: use DMA RX polling by default"
from the TTY tree until this has been sorted out?

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: pl011: use DMA RX polling by default

Making DMA RX polling optional when DMA is on was just
over-cautious: there is one single system in the kernel tree
using this facility, Ux500 and after some testing I turned
this on also for Ux500, which means it should simply be on
by default if DMA is enabled.

Cc: Jongsung Kim <neidhard.kim@lge.com>
Cc: Chanho Min <chanho.min@lge.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

treewide: Fix common typo in "identify"

Correct common misspelling of "identify" as "indentify" throughout
the kernel

Signed-off-by: Maxime Jayat <maxime@artisandeveloppeur.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

ARM: PL011: Add support for Rx DMA buffer polling.

In DMA support, The received data is not pushed to tty until the DMA buffer
is filled. But some megabyte rate chips such as BT expect fast response and
data should be pushed immediately. In order to fix this issue, We suggest
the use of the timer for polling DMA buffer.
In our test, no data loss occurred at high-baudrate as compared with interrupt-
driven (We tested with 3Mbps).
We changes:

- We add timer for polling. If we set poll_timer to 10, every 10ms,
timer handler checks the residue in the dma buffer and transfer data
to the tty. Also, last_residue is updated for the next polling.

- poll_timeout is used to prevent the timer's system cost.
If poll_timeout is set to 3000 and no data is received in 3 seconds,
we inactivate poll timer and driver falls back to interrupt-driven.
When data is received again in FIFO and UART irq is occurred, we switch
back to DMA mode and start polling.

- We use consistent DMA mappings to avoid from the frequent cache operation
of the timer function for default.

- pl011_dma_rx_chars is modified. the pending size is recalculated because
data can be taken by polling.

- the polling time is adjusted if dma rx poll is enabled but no rate is
specified. Ideal polling interval to push 1 character at every interval
is the reciprocal of 'baud rate / 10 line bits per character / 1000 ms
per sec'. But It is very aggressive to system. Experimentally,
'10000000 / baud' is suitable to receive dozens of characters. the poll rate
can be specified statically by dma_rx_poll_rate of the platform data as well.

Changes compared to v1:
- Use of consistent DMA mappings.
- Added dma_rx_poll_rate in platform data to specify the polling interval.
- Added dma_rx_poll_timeout in platform data to specify the polling timeout.

Changes compared to v2:
- Use of consistent DMA mappings for default.
- Added dma_rx_poll_enable in platform data to adjust the polling time
according to the baud rate.
- remove unnecessary lock from the polling function.

Signed-off-by: Chanho Min <chanho.min@lge.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serial: pl011: delete reset callback

Since commit 4fd0690bb0c3955983560bb2767ee82e2b197f9b
"serial: pl011: implement workaround for CTS clear event issue"
the PL011 UART is no longer at risk to hang up, so get rid
of the callback altogether.

Cc: Rajanikanth H.V <rajanikanth.hv@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ARM: 7339/1: amba/serial.h: Include types.h for resolving dependency of type bool

serial.h uses bool, but its definition is missing, as it doesn't include
types.h. Fix this by including types.h

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

amba pl011: workaround for uart registers lockup

This workaround aims to break the deadlock situation
which raises during continuous transfer of data for long
duration over uart with hardware flow control. It is
observed that CTS interrupt cannot be cleared in uart
interrupt register (ICR). Hence further transfer over
uart gets blocked.

It is seen that during such deadlock condition ICR
don't get cleared even on multiple write. This leads
pass_counter to decrease and finally reach zero. This
can be taken as trigger point to run this UART_BT_WA.

Workaround backups the register configuration, does soft
reset of UART using BIT-0 of PRCC_K_SOFTRST_SET/CLEAR
registers and restores the registers.

This patch also provides support for uart init and exit
function calls if present.

Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

amba pl011: workaround for uart registers lockup

This workaround aims to break the deadlock situation
which raises during continuous transfer of data for long
duration over uart with hardware flow control. It is
observed that CTS interrupt cannot be cleared in uart
interrupt register (ICR). Hence further transfer over
uart gets blocked.

It is seen that during such deadlock condition ICR
don't get cleared even on multiple write. This leads
pass_counter to decrease and finally reach zero. This
can be taken as trigger point to run this UART_BT_WA.

Workaround backups the register configuration, does soft
reset of UART using BIT-0 of PRCC_K_SOFTRST_SET/CLEAR
registers and restores the registers.

This patch also provides support for uart init and exit
function calls if present.

Signed-off-by: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

ARM: PL011: add DMA burst threshold support for ST variants

ST Micro variants has some specific dma burst threshold compensation,
which allows them to make better use of a DMA controller. Add support
to set this up.

Based on a patch from Linus Walleij.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: PL011: Add support for transmit DMA

Add DMA engine support for transmit to the PL011 driver. Based on a
patch from Linus Walliej, with the following changes:

- remove RX DMA support. As PL011 doesn't give us receive timeout
interrupts, we only get notified of received data when the RX DMA
has completed. This rather sucks for interactive use of the TTY.

- remove abuse of completions. Completions are supposed to be for
events, not to tell what condition buffers are in. Replace it with
a simple 'queued' bool.

- fix locking - it is only safe to access the circular buffer with the
port lock held.

- only map the DMA buffer when required - if we're ever behind an IOMMU
this helps keep IOMMU usage down, and also ensures that we're legal
when we change the scatterlist entry length.

- fix XON/XOFF sending - we must send XON/XOFF characters out as soon
as possible - waiting for up to 4095 characters in the DMA buffer
to be sent first is not acceptable.

- fix XON/XOFF receive handling - we need to stop DMA when instructed
to by the TTY layer, and restart it again when instructed to. There
is a subtle problem here: we must not completely empty the circular
buffer with DMA, otherwise we will not be notified of XON.

- change the 'enable_dma' flag into a 'using DMA' flag, and track
whether we can use TX DMA by whether the channel pointer is non-NULL.
This gives us more control over whether we use DMA in the driver.

- we don't need to have the TX DMA buffer continually allocated for
each port - instead, allocate it when the port starts up, and free
it when it's shut down. Update the 'using DMA' flag if we get
the buffer, and adjust the TTY FIFO size appropriately.

- if we're going to use PIO to send characters, use the existing IRQ
based functionality rather than reimplementing it. This also ensures
we call uart_write_wakeup() at the appropriate time, otherwise we'll
stall.

- use DMA engine helper functions for type safety.

- fix init when built as a module - we can't have to initcall functions,
so we must settle on one. This means we can eliminate the deferred
DMA initialization.

- there is no need to terminate transfers on a failed prep_slave_sg()
call - nothing has been setup, so nothing needs to be terminated.
This avoids a potential deadlock in the DMA engine code
(tasklet->callback->failed prepare->terminate->tasklet_disable
which then ends up waiting for the tasklet to finish running.)

- Dan says that the submission callback should not return an error:
| dma_submit_error() is something I should have removed after commit
| a0587bcf "ioat1: move descriptor allocation from submit to prep" all
| errors should be notified by prep failing to return a descriptor
| handle. Negative dma_cookie_t values are only returned by the
| dma_async_memcpy* calls which translate a prep failure into -ENOMEM.
So remove the error handling at that point. This also solves the
potential deadlock mentioned in the previous comment.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: 6421/1: amba-pl011: add missing ST specific registers

The ST Micro derivates have several extra interesting registers
that we may soon use for something interesting so may just as
well define them in the header.

Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: 6158/2: PL011 baudrate extension for ST-Ericssons derivative

Implementation of the ST-Ericsson baudrate extension in the PL011
block. In this modified variant it is possible to change the
sampling factor from 16 to 8, and thanks to this we can get higher
baudrates while still using the same peripheral clock.

Also replace the simple division to determine the baud divisor
with DIV_ROUND_CLOSEST() rather than a simple integer division.

Cc: Alessandro Rubini <rubini@unipv.it>
Cc: Jerzy Kasenberg <jerzy.kasenberg@tieto.com>
Signed-off-by: Marcin Mielczarczyk <marcin.mielczarczyk@tieto.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

ARM: 6157/2: PL011 TX/RX split of LCR for ST-Ericssons derivative

In the ST-Ericsson version of the PL011 the TX and RX have different
control registers.

Cc: Alessandro Rubini <rubini@unipv.it>
Signed-off-by: Marcin Mielczarczyk <marcin.mielczarczyk@tieto.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

[ARM] 5543/1: arm: serial amba: add missing declaration in serial.h

This header is sometimes included in the uncompress stage to get
register values, but no <linux/amba/bus.h> can be included there.
So declare "struct amba_device" here before using it in a prototype.

Signed-off-by: Alessandro Rubini <rubini@unipv.it>
Acked-by: Andrea Gallo <andrea.gallo@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

[ARM] 5541/1: serial/amba-pl011.c: add support for the modified port found in Nomadik

The Nomadik 8815 SoC has a slightly modified version of the PL011 block.
The patch uses the different ID value as a key to select a vendor
structure that is used to keep track of the differences, as suggested
by Russell King.

Signed-off-by: Alessandro Rubini <rubini@unipv.it>
Acked-by: Andrea Gallo <andrea.gallo@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

[SERIAL] amba-pl010: allow platforms to specify modem control method

The amba-pl010 hardware does not provide RTS and DTR control lines; it
is expected that these will be implemented using GPIO. Allow platforms
to supply a function to implement manipulation of modem control lines.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

[ARM] Move AMBA include files to include/linux/amba/

Since the ARM AMBA bus is used on MIPS as well as ARM, we need
to make the bus available for other architectures to use. Move
the AMBA include files from include/asm-arm/hardware/ to
include/linux/amba/

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>