treewide, serdev: change receive_buf() return type to size_t

receive_buf() is called from ttyport_receive_buf() that expects values
">= 0" from serdev_controller_receive_buf(), change its return type from
ssize_t to size_t.

The need for this clean-up was noticed while fixing a warning, see
commit 94d053942544 ("Bluetooth: btnxpuart: fix recv_buf() return value").
Changing the callback prototype to return an unsigned seems the best way
to document the API and ensure that is properly used.

GNSS drivers implementation of serdev receive_buf() callback return
directly the return value of gnss_insert_raw(). gnss_insert_raw()
returns a signed int, however this is not an issue since the value
returned is always positive, because of the kfifo_in() implementation.
gnss_insert_raw() could be changed to return also an unsigned, however
this is not implemented here as request by the GNSS maintainer Johan
Hovold.

Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/all/087be419-ec6b-47ad-851a-5e1e3ea5cfcc@kernel.org/
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> #for-iio
Reviewed-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Acked-by: Maximilian Luz <luzmaximilian@gmail.com> # for platform/surface
Acked-by: Lee Jones <lee@kernel.org>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240122180551.34429-1-francesco@dolcini.it
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bluetooth: btnxpuart: Fix btnxpuart_close

Fix scheduling while atomic BUG in btnxpuart_close(), properly
purge the transmit queue and free the receive skb.

[ 10.973809] BUG: scheduling while atomic: kworker/u9:0/80/0x00000002
...
[ 10.980740] CPU: 3 PID: 80 Comm: kworker/u9:0 Not tainted 6.8.0-rc7-0.0.0-devel-00005-g61fdfceacf09 #1
[ 10.980751] Hardware name: Toradex Verdin AM62 WB on Dahlia Board (DT)
[ 10.980760] Workqueue: hci0 hci_power_off [bluetooth]
[ 10.981169] Call trace:
...
[ 10.981363] uart_update_mctrl+0x58/0x78
[ 10.981373] uart_dtr_rts+0x104/0x114
[ 10.981381] tty_port_shutdown+0xd4/0xdc
[ 10.981396] tty_port_close+0x40/0xbc
[ 10.981407] uart_close+0x34/0x9c
[ 10.981414] ttyport_close+0x50/0x94
[ 10.981430] serdev_device_close+0x40/0x50
[ 10.981442] btnxpuart_close+0x24/0x98 [btnxpuart]
[ 10.981469] hci_dev_close_sync+0x2d8/0x718 [bluetooth]
[ 10.981728] hci_dev_do_close+0x2c/0x70 [bluetooth]
[ 10.981862] hci_power_off+0x20/0x64 [bluetooth]

Fixes: 689ca16e5232 ("Bluetooth: NXP: Add protocol support for NXP Bluetooth chipsets")
Cc: stable@vger.kernel.org
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Resolve TX timeout error in power save stress test

This fixes the tx timeout issue seen while running a stress test on
btnxpuart for couple of hours, such that the interval between two HCI
commands coincide with the power save timeout value of 2 seconds.

Test procedure using bash script:
<load btnxpuart.ko>
hciconfig hci0 up
//Enable Power Save feature
hcitool -i hci0 cmd 3f 23 02 00 00
while (true)
do
hciconfig hci0 leadv
sleep 2
hciconfig hci0 noleadv
sleep 2
done

Error log, after adding few more debug prints:
Bluetooth: btnxpuart_queue_skb(): 01 0A 20 01 00
Bluetooth: hci0: Set UART break: on, status=0
Bluetooth: hci0: btnxpuart_tx_wakeup() tx_work scheduled
Bluetooth: hci0: btnxpuart_tx_work() dequeue: 01 0A 20 01 00
Can't set advertise mode on hci0: Connection timed out (110)
Bluetooth: hci0: command 0x200a tx timeout

When the power save mechanism turns on UART break, and btnxpuart_tx_work()
is scheduled simultaneously, psdata->ps_state is read as PS_STATE_AWAKE,
which prevents the psdata->work from being scheduled, which is responsible
to turn OFF UART break.

This issue is fixed by adding a ps_lock mutex around UART break on/off as
well as around ps_state read/write.
btnxpuart_tx_wakeup() will now read updated ps_state value. If ps_state is
PS_STATE_SLEEP, it will first schedule psdata->work, and then it will
reschedule itself once UART break has been turned off and ps_state is
PS_STATE_AWAKE.

Tested above script for 50,000 iterations and TX timeout error was not
observed anymore.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

tty: serdev: convert to u8 and size_t

Switch character types to u8 and sizes to size_t. To conform to
characters/sizes in the rest of the tty layer.

This patch converts struct serdev_device_ops hooks and its
instantiations.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Acked-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20231206073712.17776-24-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bluetooth: btnxpuart: remove useless assignment

Remove useless assignment of rx_skb to NULL in case the skb is in error,
this is already done in h4_recv_buf() that is executed a few lines
before.

Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: fix recv_buf() return value

Serdev recv_buf() callback is supposed to return the amount of bytes
consumed, therefore an int in between 0 and count.

Do not return a negative number in case of issue, just print an error
and return count. Before this change, in case of error, the returned
negative number was internally converted to 0 in ttyport_receive_buf,
now when the receive buffer is corrupted we return the size of the whole
received data (`count`). This should allow for better recovery in case
receiver/transmitter get out of sync if some data is lost.

This fixes a WARN in ttyport_receive_buf().

Bluetooth: hci0: Frame reassembly failed (-84)
------------[ cut here ]------------
serial serial0: receive_buf returns -84 (count = 6)
WARNING: CPU: 0 PID: 37 at drivers/tty/serdev/serdev-ttyport.c:37 ttyport_receive_buf+0xd8/0xf8
Modules linked in: mwifiex_sdio(+) ...
CPU: 0 PID: 37 Comm: kworker/u4:2 Not tainted 6.7.0-rc2-00147-gf1a09972a45a #1
Hardware name: Toradex Verdin AM62 WB on Verdin Development Board (DT)
Workqueue: events_unbound flush_to_ldisc
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : ttyport_receive_buf+0xd8/0xf8
lr : ttyport_receive_buf+0xd8/0xf8
...
Call trace:
ttyport_receive_buf+0xd8/0xf8
flush_to_ldisc+0xbc/0x1a4
process_scheduled_works+0x16c/0x28c

Closes: https://lore.kernel.org/all/ZWEIhcUXfutb5SY6@francesco-nb.int.toradex.com/
Fixes: 689ca16e5232 ("Bluetooth: NXP: Add protocol support for NXP Bluetooth chipsets")
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Improve inband Independent Reset handling

This improves the inband IR command handling for NXP BT chipsets.
When the IR vendor command is received, the driver injects a HW
error event, which causes a reset sequence in hci_error_reset().
The vendor IR command is sent to the controller while hci dev
is been closed, and FW is re-downloaded when nxp_setup() is
called during hci_dev_do_open().
The HCI_SETUP flag is set in nxp_hw_err() to make sure that
nxp_setup() is been called during hci_dev_do_open().

This also makes the nxp_setup() and power save functions more
generic.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Add support for IW624 chipset

This adds support for NXP IW624 chipset in btnxpuart driver
by adding FW name and bootloader signature. Based on the
loader version bits 7:6 of the bootloader signature, the
driver can choose between selecting secure and non-secure
FW files.
For cmd5 payload during FW download, this chip has addresses
of few registers offset by 1, so added boot_reg_offset to
handle the chip specific offset.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Remove check for CTS low after FW download

This removes the unnecessary check for CTS low after FW download.

After FW download is complete, the CTS line is already seen low.
It becomes high after 2 msec, and low again after FW initialization
is complete.
This makes the current check for CTS low redundant.

This removes the wait for CTS low section and increase delay to
1200msec instead, which is sufficiant for all NXP chipsets to
initialize FW.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Add support for AW693 chipset

This adds support for NXP AW693 chipset in btnxpuart driver
by adding FW name and bootloader signature. Based on the
loader version bits 7:6 of the bootloader signature, the
driver can choose between selecting secure and non-secure
FW files.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Fix compiler warnings

This fixes the follwing compiler warning reported by kernel test robot:

drivers/bluetooth/btnxpuart.c:1332:34: warning: unused variable
'nxpuart_of_match_table' [-Wunused-const-variable]

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202305161345.eClvTYQ9-lkp@intel.com/
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Enable flow control before checking boot signature

This enables flow control before checking for bootloader signature and
deciding whether FW download is needed or not. In case of V1 bootloader
chips w8987 and w8997, it is observed that if WLAN FW is downloaded first
and power save is enabled in wlan core, bootloader signatures are not
emitted by the BT core when the chip is put to sleep. As a result, the
driver skips FW download and subsequent HCI commands get timeout errors
in dmesg as shown below:

[ 112.898867] Bluetooth: hci0: Opcode 0x c03 failed: -110
[ 114.914865] Bluetooth: hci0: Setting baudrate failed (-110)
[ 116.930856] Bluetooth: hci0: Setting wake-up method failed (-110)

By enabling the flow control, the host enables its RTS pin, and an
interrupt in chip's UART peripheral causes the bootloader to wake up,
enabling the bootloader signatures, which then helps in downloading
the bluetooth FW file.

This changes all instances of 0/1 for serdev_device_set_flow_control()
to false/true.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Fix sparse warnings

This fixes the following sparse warnings:

drivers/bluetooth/btnxpuart.c:681:23: sparse: sparse:
restricted __le16 degrades to integer
drivers/bluetooth/btnxpuart.c:690:82: sparse:
sparse: incorrect type in argument 2 (different base types)
@@ expected unsigned short [usertype] req_len
@@ got restricted __le16 [usertype] len @@
drivers/bluetooth/btnxpuart.c:690:82: sparse:
expected unsigned short [usertype] req_len
drivers/bluetooth/btnxpuart.c:690:82: sparse:
got restricted __le16 [usertype] len
drivers/bluetooth/btnxpuart.c:694:84: sparse:
sparse: incorrect type in argument 2 (different base types)
@@ expected unsigned short [usertype] req_len
@@ got restricted __le16 [usertype] len @@
drivers/bluetooth/btnxpuart.c:694:84: sparse:
expected unsigned short [usertype] req_len
drivers/bluetooth/btnxpuart.c:694:84: sparse:
got restricted __le16 [usertype] len
drivers/bluetooth/btnxpuart.c:708:23: sparse:
sparse: incorrect type in assignment (different base types)
@@ expected unsigned int [usertype] requested_len
@@ got restricted __le16 [usertype] len @@
drivers/bluetooth/btnxpuart.c:708:23: sparse:
expected unsigned int [usertype] requested_len
drivers/bluetooth/btnxpuart.c:708:23: sparse:
got restricted __le16 [usertype] len
drivers/bluetooth/btnxpuart.c:787:78: sparse:
sparse: incorrect type in argument 2 (different base types)
@@ expected unsigned short [usertype] chipid
@@ got restricted __le16 [usertype] chip_id @@
drivers/bluetooth/btnxpuart.c:787:78: sparse:
expected unsigned short [usertype] chipid
drivers/bluetooth/btnxpuart.c:787:78: sparse:
got restricted __le16 [usertype] chip_id
drivers/bluetooth/btnxpuart.c:810:74: sparse:
sparse: incorrect type in argument 2 (different base types)
@@ expected unsigned short [usertype] req_len
@@ got restricted __le16 [usertype] len @@
drivers/bluetooth/btnxpuart.c:810:74: sparse:
expected unsigned short [usertype] req_len
drivers/bluetooth/btnxpuart.c:810:74: sparse:
got restricted __le16 [usertype] len
drivers/bluetooth/btnxpuart.c:815:76: sparse:
sparse: incorrect type in argument 2 (different base types)
@@ expected unsigned short [usertype] req_len
@@ got restricted __le16 [usertype] len @@
drivers/bluetooth/btnxpuart.c:815:76: sparse:
expected unsigned short [usertype] req_len
drivers/bluetooth/btnxpuart.c:815:76: sparse:
got restricted __le16 [usertype] len
drivers/bluetooth/btnxpuart.c:834:16: sparse:
sparse: restricted __le32 degrades to integer
drivers/bluetooth/btnxpuart.c:843:55: sparse:
sparse: restricted __le32 degrades to integer
drivers/bluetooth/btnxpuart.c:844:36: sparse:
sparse: incorrect type in argument 3 (different base types)
@@ expected unsigned long [usertype]
@@ got restricted __le16 [usertype] len @@
drivers/bluetooth/btnxpuart.c:844:36: sparse:
expected unsigned long [usertype]
drivers/bluetooth/btnxpuart.c:844:36: sparse:
got restricted __le16 [usertype] len

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202304160736.Tsa0zTBU-lkp@intel.com/
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: No need to check the received bootloader signature

We can never assume the uart will deliver a complete packet to the BT
layer at once, the expected packet may be divided into several parts by
uart as uart doesn't know the received packet size, the received data
count may mismatch with the expected packet size, so here
is_valid_bootloader_signature() check may always return false.

Even we remove the count check in is_valid_bootloader_signature(), then
the first part of the data which includes the packet type can pass the
is_valid_bootloader_signature() check, but the remaining parts don't
have the packet type data still cannot pass the check, here return
directly will cause the data loss.

So need to remove the received bootloader signature check here, the
h4_recv_buf() can help us combine the different data received into one
packet. If any out-of-sync or incomplete bootloader signature is received,
it is safe to ignore and discard it, and process the next bootloader
signature.

Co-developed-by: Sherry Sun <sherry.sun@nxp.com>
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Disable Power Save feature on startup

This sets the default power save mode setting to disabled.
With this setting, this driver will behave like a normal h4 driver.
If user needs to use the power save feature, it can be enabled
using the following vendor command:
hcitool cmd 3f 23 02 00 00 (HCI_NXP_AUTO_SLEEP_MODE)

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Deasset UART break before closing serdev device

This adds a call to ps_wakeup() before closing the serdev device, to
de-assert UART break.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: btnxpuart: Add support to download helper FW file for w8997

This adds support to download helper FW file for the legacy NXP chipset
88w8997 for the btnxpuart driver. This helper FW file is necessary to
set the bootloader baudrate to 3000000 after which the actual BT FW file
can be downloaded. This change helps bring the FW download time from
around 10 sec to less than 2 sec for 88w8997 chip. For newer chipsets,
both V1 and V3 bootloader, driver sends the cmd5 and cmd7 to the chip
bootloader, and does not need a helper FW file.

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

Bluetooth: NXP: Add protocol support for NXP Bluetooth chipsets

This adds a driver based on serdev driver for the NXP BT serial protocol
based on running H:4, which can enable the built-in Bluetooth device
inside an NXP BT chip.

This driver has Power Save feature that will put the chip into sleep state
whenever there is no activity for 2000ms, and will be woken up when any
activity is to be initiated over UART.

This driver enables the power save feature by default by sending the vendor
specific commands to the chip during setup.

During setup, the driver checks if a FW is already running on the chip
by waiting for the bootloader signature, and downloads device specific FW
file into the chip over UART if bootloader signature is received..

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>