linux/drivers/tty/serial
Hugo Villeneuve b168029d67 serial: sc16is7xx: fix unconditional activation of THRI interrupt
[ Upstream commit 9915753037 ]

Commit cc4c1d05eb ("sc16is7xx: Properly resume TX after stop") changed
behavior to unconditionnaly set the THRI interrupt in sc16is7xx_tx_proc().

For example when sending a 65 bytes message, and assuming the Tx FIFO is
initially empty, sc16is7xx_handle_tx() will write the first 64 bytes of the
message to the FIFO and sc16is7xx_tx_proc() will then activate THRI. When
the THRI IRQ is fired, the driver will write the remaining byte of the
message to the FIFO, and disable THRI by calling sc16is7xx_stop_tx().

When sending a 2 bytes message, sc16is7xx_handle_tx() will write the 2
bytes of the message to the FIFO and call sc16is7xx_stop_tx(), disabling
THRI. After sc16is7xx_handle_tx() exits, control returns to
sc16is7xx_tx_proc() which will unconditionally set THRI. When the THRI IRQ
is fired, the driver simply acknowledges the interrupt and does nothing
more, since all the data has already been written to the FIFO. This results
in 2 register writes and 4 register reads all for nothing and taking
precious cycles from the I2C/SPI bus.

Fix this by enabling the THRI interrupt only when we fill the Tx FIFO to
its maximum capacity and there are remaining bytes to send in the message.

Fixes: cc4c1d05eb ("sc16is7xx: Properly resume TX after stop")
Cc:  <stable@vger.kernel.org>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-7-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-01-31 16:17:10 -08:00
..
8250 serial: 8250: omap: Don't skip resource freeing if pm_runtime_resume_and_get() failed 2024-01-25 15:27:46 -08:00
cpm_uart serial: cpm_uart: Avoid suspicious locking 2023-09-23 11:11:07 +02:00
jsm drivers: serial: jsm: fix some leaks in probe 2022-09-22 16:11:43 +02:00
21285.c TTY/Serial driver update for 6.1-rc1 2022-10-07 16:36:24 -07:00
altera_jtaguart.c tty: serial: do unlock on a common path in altera_jtaguart_console_putc() 2022-09-30 14:58:46 +02:00
altera_uart.c serial: altera_uart: fix locking in polling mode 2022-12-31 13:32:40 +01:00
amba-pl010.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
amba-pl011.c ARM: PL011: Fix DMA support 2023-12-13 18:39:27 +01:00
apbuart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
apbuart.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ar933x_uart.c serial: ar933x: Deassert Transmit Enable on ->rs485_config() 2022-09-22 16:43:05 +02:00
arc_uart.c serial: arc_uart: fix of_iomap leak in arc_serial_probe 2023-05-24 17:32:44 +01:00
atmel_serial.c serial: atmel: don't enable IRQs prematurely 2023-07-23 13:49:40 +02:00
atmel_serial.h tty: serial: atmel: Use FIELD_PREP/FIELD_GET 2022-09-22 16:32:25 +02:00
bcm63xx_uart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
clps711x.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
digicolor-usart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
dz.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
dz.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
earlycon-arm-semihost.c serial: make uart_console_write->putchar()'s character an unsigned char 2022-03-03 15:06:31 +01:00
earlycon-riscv-sbi.c serial: make uart_console_write->putchar()'s character an unsigned char 2022-03-03 15:06:31 +01:00
earlycon.c tty: move from strlcpy with unused retval to strscpy 2022-08-30 14:21:59 +02:00
fsl_linflexuart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
fsl_lpuart.c tty: serial: fsl_lpuart: Clear the error flags by writing 1 for lpuart32 platforms 2023-08-23 17:52:31 +02:00
icom.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
imx.c serial: imx: Correct clock error message in function probe() 2024-01-25 15:27:48 -08:00
imx_earlycon.c serial: make uart_console_write->putchar()'s character an unsigned char 2022-03-03 15:06:31 +01:00
ip22zilog.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
ip22zilog.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig serial: cpm_uart: Fix a COMPILE_TEST dependency 2023-06-09 10:34:26 +02:00
kgdb_nmi.c tty: drop put_tty_driver 2021-07-27 12:17:21 +02:00
kgdboc.c serial: kgdboc: Fix typo in comment 2022-06-27 14:37:09 +02:00
lantiq.c serial: lantiq: add missing interrupt ack 2023-06-21 16:00:57 +02:00
liteuart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
lpc32xx_hs.c tty: serial: extract tx_ready() from __serial_lpc32xx_tx() 2022-09-22 16:14:08 +02:00
Makefile serial: remove VR41XX serial driver 2022-07-16 08:16:01 +02:00
max310x.c serial: max310x: fix IO data corruption in batched operations 2023-05-11 23:03:01 +09:00
max3100.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
mcf.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
men_z135_uart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
meson_uart.c tty: serial: meson: fix hard LOCKUP on crtscts mode 2023-11-28 17:07:08 +00:00
milbeaut_usio.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
mpc52xx_uart.c tty: serial: switch mpc52xx_uart_int_{r,t}x_chars() to bool 2022-09-22 16:14:08 +02:00
mps2-uart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
msm_serial.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
mux.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
mvebu-uart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
mxs-auart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
omap-serial.c serial: omap: do not override settings for RS485 support 2024-01-25 15:27:41 -08:00
owl-uart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
pch_uart.c tty: pcn_uart: fix memory leak with using debugfs_lookup() 2023-03-11 13:55:39 +01:00
pic32_uart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
pmac_zilog.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
pmac_zilog.h serial: pmac_zilog: remove unused uart_pmac_port::termios_cache 2022-05-19 18:23:19 +02:00
pxa.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
qcom_geni_serial.c serial: qcom-geni: fix opp vote on shutdown 2023-09-06 21:27:01 +01:00
rda-uart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
rp2.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
sa1100.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
samsung_tty.c tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() when iterating clk 2023-07-23 13:49:41 +02:00
sb1250-duart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
sc16is7xx.c serial: sc16is7xx: fix unconditional activation of THRI interrupt 2024-01-31 16:17:10 -08:00
sccnxp.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
serial-tegra.c serial: tegra: handle clk prepare error in tegra_uart_hw_init() 2023-09-13 09:42:56 +02:00
serial_core.c serial: core, imx: do not set RS485 enabled if it is not supported 2024-01-25 15:27:40 -08:00
serial_mctrl_gpio.c Documentation: serial: move GPIO kernel-doc to the functions 2022-07-28 10:37:42 +02:00
serial_mctrl_gpio.h serial: mctrl_gpio: add a new API to enable / disable wake_irq 2022-02-08 11:07:16 +01:00
serial_txx9.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
sh-sci.c tty: serial: sh-sci: Fix Rx on RZ/G2L SCI 2023-04-13 16:55:28 +02:00
sh-sci.h serial: sh-sci: Add support for RZ/G2L SoC 2021-06-04 15:12:40 +02:00
sifive.c serial: sifive: Fix sifive_serial_console_setup() section 2023-08-03 10:24:08 +02:00
sprd_serial.c serial: sprd: Fix DMA buffer leak issue 2023-09-13 09:42:52 +02:00
st-asc.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
stm32-usart.c serial: stm32: Ignore return value of uart_remove_one_port() in .remove() 2023-08-23 17:52:23 +02:00
stm32-usart.h serial: stm32: make info structs static to avoid sparse warnings 2022-07-28 10:35:23 +02:00
suncore.c tty: Use of_node_name_{eq,prefix} for node name comparisons 2018-12-17 16:12:17 +01:00
sunhv.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
sunplus-uart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
sunsab.c serial: sunsab: Fix error handling in sunsab_init() 2022-12-31 13:32:40 +01:00
sunsab.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sunsu.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
sunzilog.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
sunzilog.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tegra-tcu.c Merge 7e2cd21e02 ("Merge tag 'tty-6.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty") into tty-next 2022-09-25 09:22:13 +02:00
timbuart.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
timbuart.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
uartlite.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
ucc_uart.c serial: ucc_uart: Remove custom frame size calculation 2022-08-30 14:28:33 +02:00
vt8500_serial.c tty: serial: move and cleanup vt8500_tx_empty() 2022-09-22 16:14:07 +02:00
xilinx_uartps.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
zs.c serial: Make ->set_termios() old ktermios const 2022-08-30 14:22:35 +02:00
zs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00