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linux/drivers/tty/serial
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Claudiu Beznea 7415bc5198 serial: sh-sci: Check if TX data was written to device in .tx_empty() 
commit 7cc0e0a43a upstream.

On the Renesas RZ/G3S, when doing suspend to RAM, the uart_suspend_port()
is called. The uart_suspend_port() calls 3 times the
struct uart_port::ops::tx_empty() before shutting down the port.

According to the documentation, the struct uart_port::ops::tx_empty()
API tests whether the transmitter FIFO and shifter for the port is
empty.

The Renesas RZ/G3S SCIFA IP reports the number of data units stored in the
transmit FIFO through the FDR (FIFO Data Count Register). The data units
in the FIFOs are written in the shift register and transmitted from there.
The TEND bit in the Serial Status Register reports if the data was
transmitted from the shift register.

In the previous code, in the tx_empty() API implemented by the sh-sci
driver, it is considered that the TX is empty if the hardware reports the
TEND bit set and the number of data units in the FIFO is zero.

According to the HW manual, the TEND bit has the following meaning:

0: Transmission is in the waiting state or in progress.
1: Transmission is completed.

It has been noticed that when opening the serial device w/o using it and
then switch to a power saving mode, the tx_empty() call in the
uart_port_suspend() function fails, leading to the "Unable to drain
transmitter" message being printed on the console. This is because the
TEND=0 if nothing has been transmitted and the FIFOs are empty. As the
TEND=0 has double meaning (waiting state, in progress) we can't
determined the scenario described above.

Add a software workaround for this. This sets a variable if any data has
been sent on the serial console (when using PIO) or if the DMA callback has
been called (meaning something has been transmitted). In the tx_empty()
API the status of the DMA transaction is also checked and if it is
completed or in progress the code falls back in checking the hardware
registers instead of relying on the software variable.

Fixes: 73a19e4c03 ("serial: sh-sci: Add DMA support.")
Cc: stable@vger.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20241125115856.513642-1-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2024-12-19 18:12:58 +01:00
..
8250 serial: 8250_dw: Add Sophgo SG2044 quirk 2024-12-14 20:04:09 +01:00
jsm tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
21285.c serial: 21285: Use port lock wrappers 2023-09-18 11:18:08 +02:00
altera_jtaguart.c serial: altera_jtaguart: Convert to platform remove callback returning void 2023-11-23 19:12:30 +00:00
altera_uart.c tty/serial: altera_uart: use more informative labels in /proc/interrupts 2024-01-04 16:20:51 +01:00
amba-pl010.c serial: amba-pl010: Use port lock wrappers 2023-09-18 11:18:09 +02:00
amba-pl011.c serial: amba-pl011: fix build regression 2024-12-05 14:02:54 +01:00
apbuart.c serial: apbuart: fix console prompt on qemu 2024-01-04 16:21:06 +01:00
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: Remove unneeded static structure 2024-04-09 17:07:10 +02:00
arc_uart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
atmel_serial.c tty: atmel_serial: use the correct RTS flag. 2024-08-13 11:06:46 +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: bcm63xx-uart: fix tx after conversion to uart_port_tx_limited() 2024-06-24 16:14:48 +02:00
clps711x.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
cpm_uart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
cpm_uart.h serial: cpm_uart: Remove cpm_uart/ subdirectory 2023-08-04 15:08:30 +02:00
digicolor-usart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
dz.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +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-riscv-sbi.c tty/serial: Add RISC-V SBI debug console based earlycon 2024-01-10 07:04:04 -08:00
earlycon-semihost.c serial: Rename earlycon semihost driver 2023-01-19 14:58:19 +01:00
earlycon.c earlycon: Let users set the clock frequency 2023-01-19 14:56:44 +01:00
esp32_acm.c tty: add missing MODULE_DESCRIPTION() macros 2024-06-24 16:10:11 +02:00
esp32_uart.c tty: add missing MODULE_DESCRIPTION() macros 2024-06-24 16:10:11 +02:00
fsl_linflexuart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
fsl_lpuart.c tty: serial: fsl_lpuart: mark last busy before uart_add_one_port 2024-08-13 11:05:19 +02:00
icom.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
imx.c serial: imx: Update mctrl old_status on RTSD interrupt 2024-10-11 08:28:45 +02:00
imx_earlycon.c serial: make uart_console_write->putchar()'s character an unsigned char 2022-03-03 15:06:31 +01:00
ip22zilog.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +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: sc16is7xx: re-add Kconfig SPI or I2C dependency 2024-06-04 14:10:28 +02:00
kgdb_nmi.c tty: make tty_operations::write()'s count size_t 2023-08-11 21:12:46 +02:00
kgdboc.c serial: kgdboc: Fix NMI-safety problems from keyboard reset code 2024-04-26 17:14:10 +01:00
lantiq.c serial: lantiq: Convert to platform remove callback returning void 2023-11-23 19:12:32 +00:00
liteuart.c serial: liteuart: Convert to platform remove callback returning void 2023-11-23 19:12:32 +00:00
lpc32xx_hs.c serial: lpc32xx_hs: Use uart_prepare_sysrq_char() to handle sysrq. 2024-03-02 22:06:21 +01:00
ma35d1_serial.c tty: serial: ma35d1: Add a NULL check for of_node 2024-07-03 16:12:06 +02:00
Makefile serial: sc16is7xx: rename Kconfig CONFIG_SERIAL_SC16IS7XX_CORE 2024-06-04 14:10:28 +02:00
max310x.c tty: serial: max310x: convert to use maple tree register cache 2024-04-09 16:50:36 +02:00
max3100.c move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
mcf.c tty: mcf: MCF54418 has 10 UARTS 2024-06-24 16:13:05 +02:00
men_z135_uart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
meson_uart.c serial: meson+qcom: don't advance the kfifo twice 2024-04-16 09:05:43 +02:00
milbeaut_usio.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
mpc52xx_uart.c serial: mpc52xx: Convert to platform remove callback returning void 2023-11-23 19:12:32 +00:00
mps2-uart.c serial: mps2-uart: Use port lock wrappers 2023-09-18 11:18:12 +02:00
msm_serial.c serial: msm: check dma_map_sg() return value properly 2024-04-20 07:58:42 +02:00
mux.c tty: serial: use uart_port_tx_limited() 2022-11-03 03:32:40 +01:00
mvebu-uart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
mxs-auart.c Merge 6.9-rc5 into tty-next 2024-04-23 13:24:45 +02:00
omap-serial.c serial: omap: remove redundant assignment to variable tmout 2024-04-11 14:08:36 +02:00
owl-uart.c tty: add missing MODULE_DESCRIPTION() macros 2024-06-24 16:10:11 +02:00
pch_uart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
pic32_uart.c serial: pic32_uart: Replace of_gpio.h by proper one 2024-04-09 15:48:43 +02:00
pmac_zilog.c Merge 6.9-rc5 into tty-next 2024-04-23 13:24:45 +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: pxa: Use uart_prepare_sysrq_char(). 2024-03-02 22:06:21 +01:00
qcom_geni_serial.c serial: qcom-geni: rename suspend functions 2024-10-11 08:39:24 +02:00
rda-uart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
rp2.c tty: rp2: Fix reset with non forgiving PCIe host bridges 2024-09-11 15:46:55 +02:00
sa1100.c serial: sa1100: Convert to platform remove callback returning void 2023-11-23 19:12:33 +00:00
samsung_tty.c tty: serial: samsung: Fix serial rx on Apple A7-A9 2024-09-11 15:47:13 +02:00
sb1250-duart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
sc16is7xx.c serial: sc16is7xx: convert bitmask definitions to use BIT() macro 2024-09-03 10:47:10 +02:00
sc16is7xx.h serial: sc16is7xx: split into core and I2C/SPI parts (sc16is7xx_regcfg) 2024-04-11 14:08:08 +02:00
sc16is7xx_i2c.c serial: sc16is7xx: split into core and I2C/SPI parts (sc16is7xx_regcfg) 2024-04-11 14:08:08 +02:00
sc16is7xx_spi.c serial: sc16is7xx: split into core and I2C/SPI parts (sc16is7xx_regcfg) 2024-04-11 14:08:08 +02:00
sccnxp.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
serial-tegra.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
serial_base.h serial: core: Add serial_base_match_and_update_preferred_console() 2024-07-04 15:41:44 +02:00
serial_base_bus.c Driver core changes for 6.11-rc1 2024-07-25 10:42:22 -07:00
serial_core.c TTY/Serial driver update for 6.12-rc1 2024-09-26 09:59:50 -07:00
serial_ctrl.c serial: core: Start managing serial controllers to enable runtime PM 2023-05-31 10:46:59 +01:00
serial_mctrl_gpio.c tty: add missing MODULE_DESCRIPTION() macros 2024-06-24 16:10:11 +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_port.c serial: port: Don't block system suspend even if bytes are left to xmit 2024-06-04 14:09:47 +02:00
serial_txx9.c serial: txx9: Add missing #include <asm/txx9/generic.h> 2024-01-27 19:05:39 -08:00
sh-sci.c serial: sh-sci: Check if TX data was written to device in .tx_empty() 2024-12-19 18:12:58 +01:00
sh-sci.h tty: serial: sh-sci: Add support for tx end interrupt handling 2023-04-20 13:47:33 +02:00
sifive.c serial: sifive: Remove 0 from fu540-c000-uart0 binding. 2024-04-09 15:48:46 +02:00
sprd_serial.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
st-asc.c serial: st-asc: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr() 2024-07-31 12:32:25 +02:00
stm32-usart.c Merge 6.9-rc5 into tty-next 2024-04-23 13:24:45 +02:00
stm32-usart.h serial: stm32: get FIFO size from hwcfg register 2024-01-27 19:04:11 -08:00
suncore.c tty: Use of_node_name_{eq,prefix} for node name comparisons 2018-12-17 16:12:17 +01:00
sunhv.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
sunplus-uart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
sunsab.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
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 tty: sunsu: Simplify device_node cleanup by using __free 2024-06-04 14:00:16 +02:00
sunzilog.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +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 tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
timbuart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
timbuart.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
uartlite.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
ucc_uart.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +02:00
vt8500_serial.c serial: vt8500: Use port lock wrappers 2023-09-18 11:18:16 +02:00
xilinx_uartps.c serial: xilinx_uartps: Make cdns_rs485_supported static 2024-09-03 10:46:58 +02:00
zs.c tty: serial: switch from circ_buf to kfifo 2024-04-09 15:28:03 +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