linux-stable.git/drivers/tty, branch v5.4.223 Linux kernel stable tree serial: 8250: Fix restoring termios speed after suspend 2022-10-26T11:22:41+00:00 Pali Rohár pali@kernel.org 2022-09-24T10:43:24+00:00 558a9fcb6ce706f710973864db905b188decd478 [ Upstream commit 379a33786d489ab81885ff0b3935cfeb36137fea ] Since commit edc6afc54968 ("tty: switch to ktermios and new framework") termios speed is no longer stored only in c_cflag member but also in new additional c_ispeed and c_ospeed members. If BOTHER flag is set in c_cflag then termios speed is stored only in these new members. Since commit 027b57170bf8 ("serial: core: Fix initializing and restoring termios speed") termios speed is available also in struct console. So properly restore also c_ispeed and c_ospeed members after suspend to fix restoring termios speed which is not represented by Bnnn constant. Fixes: 4516d50aabed ("serial: 8250: Use canary to restart console after suspend") Signed-off-by: Pali Rohár <pali@kernel.org> Link: https://lore.kernel.org/r/20220924104324.4035-1-pali@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 379a33786d489ab81885ff0b3935cfeb36137fea ]

Since commit edc6afc54968 ("tty: switch to ktermios and new framework")
termios speed is no longer stored only in c_cflag member but also in new
additional c_ispeed and c_ospeed members. If BOTHER flag is set in c_cflag
then termios speed is stored only in these new members.

Since commit 027b57170bf8 ("serial: core: Fix initializing and restoring
termios speed") termios speed is available also in struct console.

So properly restore also c_ispeed and c_ospeed members after suspend to fix
restoring termios speed which is not represented by Bnnn constant.

Fixes: 4516d50aabed ("serial: 8250: Use canary to restart console after suspend")
Signed-off-by: Pali Rohár <pali@kernel.org>
Link: https://lore.kernel.org/r/20220924104324.4035-1-pali@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tty: serial: fsl_lpuart: disable dma rx/tx use flags in lpuart_dma_shutdown 2022-10-26T11:22:40+00:00 Sherry Sun sherry.sun@nxp.com 2022-09-20T11:17:03+00:00 29b897ac7b990882c74bd08605692214e7e58b83 [ Upstream commit 316ae95c175a7d770d1bfe4c011192712f57aa4a ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 316ae95c175a7d770d1bfe4c011192712f57aa4a ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers: serial: jsm: fix some leaks in probe 2022-10-26T11:22:40+00:00 Dan Carpenter dan.carpenter@oracle.com 2022-09-22T11:22:47+00:00 744c2d33a88b082d9d504520f0132b3d688547b2 [ Upstream commit 1d5859ef229e381f4db38dce8ed58e4bf862006b ] This error path needs to unwind instead of just returning directly. Fixes: 03a8482c17dd ("drivers: serial: jsm: Enable support for Digi Classic adapters") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Link: https://lore.kernel.org/r/YyxFh1+lOeZ9WfKO@kili Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1d5859ef229e381f4db38dce8ed58e4bf862006b ]

This error path needs to unwind instead of just returning directly.

Fixes: 03a8482c17dd ("drivers: serial: jsm: Enable support for Digi Classic adapters")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YyxFh1+lOeZ9WfKO@kili
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tty: xilinx_uartps: Fix the ignore_status 2022-10-26T11:22:36+00:00 Shubhrajyoti Datta shubhrajyoti.datta@xilinx.com 2022-07-29T11:47:45+00:00 80a955dabb82e3cbf83ff54300378a90dba8541d [ Upstream commit b8a6c3b3d4654fba19881cc77da61eac29f57cae ] Currently the ignore_status is not considered in the isr. Add a check to add the ignore_status. Fixes: 61ec9016988f ("tty/serial: add support for Xilinx PS UART") Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com> Link: https://lore.kernel.org/r/20220729114748.18332-5-shubhrajyoti.datta@xilinx.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b8a6c3b3d4654fba19881cc77da61eac29f57cae ]

Currently the ignore_status is not considered in the isr.
Add a check to add the ignore_status.

Fixes: 61ec9016988f ("tty/serial: add support for Xilinx PS UART")
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/20220729114748.18332-5-shubhrajyoti.datta@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: tegra-tcu: Use uart_xmit_advance(), fixes icount.tx accounting 2022-09-28T09:04:08+00:00 Ilpo Järvinen ilpo.jarvinen@linux.intel.com 2022-09-01T14:39:34+00:00 9eb710d1843aeef8166a5a23bd7e374c584375ae commit 1d10cd4da593bc0196a239dcc54dac24b6b0a74e upstream. Tx'ing does not correctly account Tx'ed characters into icount.tx. Using uart_xmit_advance() fixes the problem. Fixes: 2d908b38d409 ("serial: Add Tegra Combined UART driver") Cc: <stable@vger.kernel.org> # serial: Create uart_xmit_advance() Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220901143934.8850-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1d10cd4da593bc0196a239dcc54dac24b6b0a74e upstream.

Tx'ing does not correctly account Tx'ed characters into icount.tx.
Using uart_xmit_advance() fixes the problem.

Fixes: 2d908b38d409 ("serial: Add Tegra Combined UART driver")
Cc: <stable@vger.kernel.org> # serial: Create uart_xmit_advance()
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220901143934.8850-4-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: tegra: Use uart_xmit_advance(), fixes icount.tx accounting 2022-09-28T09:04:08+00:00 Ilpo Järvinen ilpo.jarvinen@linux.intel.com 2022-09-01T14:39:33+00:00 6cc0434f9d44eae6e6b4d334a7837f9e883de97e commit 754f68044c7dd6c52534ba3e0f664830285c4b15 upstream. DMA complete & stop paths did not correctly account Tx'ed characters into icount.tx. Using uart_xmit_advance() fixes the problem. Fixes: e9ea096dd225 ("serial: tegra: add serial driver") Cc: <stable@vger.kernel.org> # serial: Create uart_xmit_advance() Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220901143934.8850-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 754f68044c7dd6c52534ba3e0f664830285c4b15 upstream.

DMA complete & stop paths did not correctly account Tx'ed characters
into icount.tx. Using uart_xmit_advance() fixes the problem.

Fixes: e9ea096dd225 ("serial: tegra: add serial driver")
Cc: <stable@vger.kernel.org> # serial: Create uart_xmit_advance()
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220901143934.8850-3-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: serial: atmel: Preserve previous USART mode if RS485 disabled 2022-09-28T09:04:02+00:00 Sergiu Moga sergiu.moga@microchip.com 2022-08-24T14:29:03+00:00 da8ac086943eb93199e41530f1b89f180e0edf32 [ Upstream commit 692a8ebcfc24f4a5bea0eb2967e450f584193da6 ] Whenever the atmel_rs485_config() driver method would be called, the USART mode is reset to normal mode before even checking if RS485 flag is set, thus resulting in losing the previous USART mode in the case where the checking fails. Some tools, such as `linux-serial-test`, lead to the driver calling this method when doing the setup of the serial port: after setting the port mode (Hardware Flow Control, Normal Mode, RS485 Mode, etc.), `linux-serial-test` tries to enable/disable RS485 depending on the commandline arguments that were passed. Example of how this issue could reveal itself: When doing a serial communication with Hardware Flow Control through `linux-serial-test`, the tool would lead to the driver roughly doing the following: - set the corresponding bit to 1 (ATMEL_US_USMODE_HWHS bit in the ATMEL_US_MR register) through the atmel_set_termios() to enable Hardware Flow Control - disable RS485 through the atmel_config_rs485() method Thus, when the latter is called, the mode will be reset and the previously set bit is unset, leaving USART in normal mode instead of the expected Hardware Flow Control mode. This fix ensures that this reset is only done if the checking for RS485 succeeds and that the previous mode is preserved otherwise. Fixes: e8faff7330a35 ("ARM: 6092/1: atmel_serial: support for RS485 communications") Cc: stable <stable@kernel.org> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Sergiu Moga <sergiu.moga@microchip.com> Link: https://lore.kernel.org/r/20220824142902.502596-1-sergiu.moga@microchip.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 692a8ebcfc24f4a5bea0eb2967e450f584193da6 ]

Whenever the atmel_rs485_config() driver method would be called,
the USART mode is reset to normal mode before even checking if
RS485 flag is set, thus resulting in losing the previous USART
mode in the case where the checking fails.

Some tools, such as `linux-serial-test`, lead to the driver calling
this method when doing the setup of the serial port: after setting the
port mode (Hardware Flow Control, Normal Mode, RS485 Mode, etc.),
`linux-serial-test` tries to enable/disable RS485 depending on
the commandline arguments that were passed.

Example of how this issue could reveal itself:
When doing a serial communication with Hardware Flow Control through
`linux-serial-test`, the tool would lead to the driver roughly doing
the following:
- set the corresponding bit to 1 (ATMEL_US_USMODE_HWHS bit in the
ATMEL_US_MR register) through the atmel_set_termios() to enable
Hardware Flow Control
- disable RS485 through the atmel_config_rs485() method
Thus, when the latter is called, the mode will be reset and the
previously set bit is unset, leaving USART in normal mode instead of
the expected Hardware Flow Control mode.

This fix ensures that this reset is only done if the checking for
RS485 succeeds and that the previous mode is preserved otherwise.

Fixes: e8faff7330a35 ("ARM: 6092/1: atmel_serial: support for RS485 communications")
Cc: stable <stable@kernel.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Sergiu Moga <sergiu.moga@microchip.com>
Link: https://lore.kernel.org/r/20220824142902.502596-1-sergiu.moga@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: atmel: remove redundant assignment in rs485_config 2022-09-28T09:04:02+00:00 Lino Sanfilippo LinoSanfilippo@gmx.de 2022-04-10T10:46:42+00:00 e56a402819974b8f4b9e79fb3bd7a6b82f2c0fe9 [ Upstream commit 60efd0513916f195dd85bfbf21653f74f9ab019c ] In uart_set_rs485_config() the serial core already assigns the passed serial_rs485 struct to the uart port. So remove the assignment from the drivers rs485_config() function to avoid redundancy. Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com> Acked-by: Richard Genoud <richard.genoud@gmail.com> Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Link: https://lore.kernel.org/r/20220410104642.32195-10-LinoSanfilippo@gmx.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: 692a8ebcfc24 ("tty: serial: atmel: Preserve previous USART mode if RS485 disabled") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 60efd0513916f195dd85bfbf21653f74f9ab019c ]

In uart_set_rs485_config() the serial core already assigns the passed
serial_rs485 struct to the uart port.

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

Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20220410104642.32195-10-LinoSanfilippo@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 692a8ebcfc24 ("tty: serial: atmel: Preserve previous USART mode if RS485 disabled")
Signed-off-by: Sasha Levin <sashal@kernel.org>
tty/serial: atmel: RS485 & ISO7816: wait for TXRDY before sending data 2022-09-28T09:04:02+00:00 Codrin.Ciubotariu@microchip.com Codrin.Ciubotariu@microchip.com 2020-01-07T11:17:47+00:00 85a64208b319183cf565fda94a3db427f6eb1d54 [ Upstream commit 477b8383100023ea0769979cff67e9be3a720397 ] At this moment, TXEMPTY is checked before sending data on RS485 and ISO7816 modes. However, TXEMPTY is risen when FIFO (if used) or the Transmit Shift Register are empty, even though TXRDY might be up and controller is able to receive data. Since the controller sends data only when TXEMPTY is ready, on RS485, when DMA is not used, the RTS pin is driven low after each byte. With this patch, the characters will be transmitted when TXRDY is up and so, RTS pin will remain high between bytes. The performance improvement on RS485 is about 8% with a baudrate of 300. Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com> Acked-by: Richard Genoud <richard.genoud@gmail.com> Link: https://lore.kernel.org/r/20200107111656.26308-1-codrin.ciubotariu@microchip.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: 692a8ebcfc24 ("tty: serial: atmel: Preserve previous USART mode if RS485 disabled") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 477b8383100023ea0769979cff67e9be3a720397 ]

At this moment, TXEMPTY is checked before sending data on RS485 and ISO7816
modes. However, TXEMPTY is risen when FIFO (if used) or the Transmit Shift
Register are empty, even though TXRDY might be up and controller is able to
receive data. Since the controller sends data only when TXEMPTY is ready,
on RS485, when DMA is not used, the RTS pin is driven low after each byte.
With this patch, the characters will be transmitted when TXRDY is up and
so, RTS pin will remain high between bytes.
The performance improvement on RS485 is about 8% with a baudrate of 300.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Link: https://lore.kernel.org/r/20200107111656.26308-1-codrin.ciubotariu@microchip.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: 692a8ebcfc24 ("tty: serial: atmel: Preserve previous USART mode if RS485 disabled")
Signed-off-by: Sasha Levin <sashal@kernel.org>
tty: serial: lpuart: disable flow control while waiting for the transmit engine to complete 2022-09-15T10:04:51+00:00 Sherry Sun sherry.sun@nxp.com 2022-08-21T10:15:27+00:00 a6b7e8d975308371b21425faefcfbd14d267d353 commit d5a2e0834364377a5d5a2fff1890a0b3f0bafd1f upstream. 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> 
commit d5a2e0834364377a5d5a2fff1890a0b3f0bafd1f upstream.

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>