linux/drivers/tty/serial
Nathan Rossi 6ecde472b0 tty: xuartps: Fix RX hang, and TX corruption in termios call
The implementation of flushing the RX FIFO breaks in a number of cases,
it is impossible to ensure an complete flush of the RX FIFO due to the
hardware not allowing the use of the FIFOs when the receiver is disabled
(Reading from the FIFO register does not remove it from the FIFO when
the RX_EN=0 or RX_DIS=1). Additionally during an initial set_termios
call where RX_DIS=1 causes a hang waiting forever for the RX FIFO to
empty. On top of this the FIFO will be cleared by the use of the RXRST
bits on the Control Register, making the RX flush pointless (as it does
not preserve the data read anyway).

Due to the TXRST the TX FIFO and transmitter can be interrupted during
frame trasmission, causing corruption and additionally data lost in the
FIFO. Most other serial drivers do not flush or clear the FIFOs during
a termios configuration change and as such do not have issues with
corruption. For this UART controller is it required that the TXRST/RXRST
bit be flagged during the change, this means that the data in the FIFO
will be dropped when changing configuration. In order to prevent data
loss and corruption of the transmitted data, wait until the TX FIFO is
empty before changing the configuration. The performance of this may
cause the set_termios call to take a longer amount of time especially
on lower baud rates, however it is comparable to the same performance
hit that a console_write call costs.

Signed-off-by: Nathan Rossi <nathan.rossi@xilinx.com>
Acked-by: Anirudha Sarangi <anirudh@xilinx.com>
Acked-by: Harini Katakam <harinik@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-02 10:11:25 -08:00
..
8250 serial: 8250_pnp: Enable PNP_CONSOLE for console ports 2015-02-02 10:11:25 -08:00
cpm_uart Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
jsm serial: jsm: Fix unnecessary space before function ptr arguments 2014-11-25 17:06:38 -08:00
21285.c serial: treewide: Remove empty implementations of enable_ms() 2014-07-09 17:29:38 -07:00
68328serial.c
altera_jtaguart.c serial: altera-juart: fix NULL device in log message 2015-01-09 14:28:17 -08:00
altera_uart.c serial: altera-uart: fix NULL device in log message 2015-01-09 14:28:17 -08:00
amba-pl010.c serial: Test/disable MSIs if switching from N_PPS 2014-11-06 14:57:27 -08:00
amba-pl011.c serial: pl011: Add device tree support for RX DMA polling 2014-11-07 08:35:56 -08:00
apbuart.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
apbuart.h
ar933x_uart.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
arc_uart.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
atmel_serial.c tty/serial: at91: fix typo and indentation 2015-01-09 14:20:49 -08:00
bcm63xx_uart.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
bfin_sport_uart.c tty: pr_warning->pr_warn and logging neatening 2014-11-25 17:06:38 -08:00
bfin_sport_uart.h
bfin_uart.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
clps711x.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
crisv10.c cris: Remove obsolete ASYNC_SPLIT_TERMIOS behavior 2014-11-05 20:18:30 -08:00
crisv10.h cris: Remove obsolete ASYNC_SPLIT_TERMIOS behavior 2014-11-05 20:18:30 -08:00
digicolor-usart.c tty/serial: digicolor: remove sysrq reference 2015-02-02 10:11:25 -08:00
dz.c serial: treewide: Remove empty implementations of enable_ms() 2014-07-09 17:29:38 -07:00
dz.h
earlycon-arm-semihost.c tty/serial: add arm/arm64 semihosting earlycon 2014-04-24 16:32:27 -07:00
earlycon.c tty/serial: earlycon: Fix print for implied MMIO case 2014-11-05 19:45:52 -08:00
efm32-uart.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
fsl_lpuart.c tty: serial: fsl_lpuart: terminate DMA on buffer flush 2015-02-02 10:09:55 -08:00
icom.c serial: icom: fix error return code 2014-11-25 17:06:39 -08:00
icom.h
ifx6x60.c serial: ifx6x60: Remove casting the return value which is a void pointer 2013-09-26 14:29:58 -07:00
ifx6x60.h
imx.c serial: imx: Fix imx_flush_buffer() 2015-02-02 10:11:24 -08:00
ioc3_serial.c serial: treewide: Remove empty implementations of enable_ms() 2014-07-09 17:29:38 -07:00
ioc4_serial.c serial: treewide: Remove empty implementations of enable_ms() 2014-07-09 17:29:38 -07:00
ip22zilog.c serial: use container_of to resolve uart_ip22zilog_port from uart_port 2014-11-05 19:20:52 -08:00
ip22zilog.h
Kconfig x86, mrst: remove Moorestown specific serial drivers 2015-02-02 10:11:24 -08:00
kgdb_nmi.c serial: kgdb_nmi: No CON_ENABLED by default 2014-09-08 16:26:07 -07:00
kgdboc.c treewide: Convert retrun typos to return 2013-09-04 12:26:36 +02:00
lantiq.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
lpc32xx_hs.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
m32r_sio_reg.h
m32r_sio.c serial: use container_of to resolve uart_sio_port from uart_port 2014-11-05 19:20:52 -08:00
m32r_sio.h
Makefile x86, mrst: remove Moorestown specific serial drivers 2015-02-02 10:11:24 -08:00
max310x.c drivers/max310: Use the rs485 functions on serial_core 2014-11-06 15:00:15 -08:00
max3100.c
mcf.c serial: mcf: fix no driver name in probe output 2015-01-09 14:06:57 -08:00
men_z135_uart.c tty: serial: men_z135_uart: Add terminating entry for men_z135_ids 2014-11-25 17:06:38 -08:00
meson_uart.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
mfd.c More ACPI and power management updates for 3.19-rc1 2014-12-18 20:28:33 -08:00
mpc52xx_uart.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
mpsc.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
msm_serial_hs.c More ACPI and power management updates for 3.19-rc1 2014-12-18 20:28:33 -08:00
msm_serial.c tty: serial: msm_serial: Remove console unregistration from driver exit. 2015-02-02 10:11:25 -08:00
msm_serial.h tty: serial: msm: Support sysrq on uartDM devices 2014-11-06 14:57:22 -08:00
msm_smd_tty.c
mux.c serial: treewide: Remove empty implementations of enable_ms() 2014-07-09 17:29:38 -07:00
mxs-auart.c serial: mxs-auart: Remove unneeded zeroing of 'ret' 2015-02-02 10:11:25 -08:00
netx-serial.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
nwpserial.c serial: Fix build failure caused by missing header file 2014-09-08 16:17:45 -07:00
of_serial.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
omap-serial.c trivial fixes for omap-serial 2015-01-09 14:10:46 -08:00
pch_uart.c pch_uart: don't hardcode PCI slot to get DMA device 2014-08-01 16:04:21 -07:00
pmac_zilog.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
pmac_zilog.h
pnx8xxx_uart.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
pxa.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
rp2.c tty: remove DEFINE_PCI_DEVICE_TABLE macro 2013-12-08 17:09:07 -08:00
sa1100.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
samsung.c Merge 3.19-rc5 into tty-next 2015-01-19 07:02:50 +08:00
samsung.h serial: samsung: add DMA support for RX 2015-01-09 14:25:39 -08:00
sb1250-duart.c serial: Fix IGNBRK handling 2014-06-19 13:04:52 -07:00
sc16is7xx.c serial/sc16is7xx: Use the rs485 functions on serial_core 2014-11-06 14:59:21 -08:00
sccnxp.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
serial_core.c serial: fix parisc boot hang 2015-01-02 12:19:28 -08:00
serial_ks8695.c serial: Fix IGNBRK handling 2014-06-19 13:04:52 -07:00
serial_mctrl_gpio.c serial: mctrl_gpio: use gpiod_set_array function 2014-12-02 14:25:42 +01:00
serial_mctrl_gpio.h tty/serial: Add GPIOLIB helpers for controlling modem lines 2014-05-28 12:49:14 -07:00
serial_txx9.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
serial-tegra.c serial: tegra: clean up tty-flag assignments 2014-11-25 17:06:39 -08:00
sh-sci.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
sh-sci.h serial: sh-sci: Move overrun_bit and error_mask fields out of pdata 2013-12-24 11:17:48 +09:00
sirfsoc_uart.c serial: sirf: rename marco to atlas7 2015-01-09 14:17:59 -08:00
sirfsoc_uart.h serial: sirf: rename marco to atlas7 2015-01-09 14:17:59 -08:00
sn_console.c serial: treewide: Remove empty implementations of enable_ms() 2014-07-09 17:29:38 -07:00
st-asc.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
suncore.c
sunhv.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
sunsab.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
sunsab.h
sunsu.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
sunzilog.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
sunzilog.h
tilegx.c serial: treewide: Remove empty implementations of enable_ms() 2014-07-09 17:29:38 -07:00
timbuart.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
timbuart.h
uartlite.c tty: serial: uartlite: Remove .owner field for driver 2014-09-08 16:09:13 -07:00
ucc_uart.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
vr41xx_siu.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
vt8500_serial.c tty: serial: drop owner assignment from platform_drivers 2014-10-20 16:21:45 +02:00
xilinx_uartps.c tty: xuartps: Fix RX hang, and TX corruption in termios call 2015-02-02 10:11:25 -08:00
zs.c serial: Fix IGNBRK handling 2014-06-19 13:04:52 -07:00
zs.h