linux/drivers/tty/serial
Peter Senna Tschudin 18a4208826 imx-serial: Reduce RX DMA startup latency when opening for reading
Reduce RX DMA start latency for the first reception when port is opened
for reading. Instead of waiting for an interrupt signaling data on RX
FIFO or data too old on RX FIFO, start RX DMA immediately when the
serial port is opened for reading.

Before this patch, the average RX DMA latency for the first reception
was 42489 microseconds with a standard deviation of 25721 microseconds
in 36 samples.

After the patch the average RX DMA latency for the first reception, when
the serial port is opened for reading, is 653 microseconds with a
standard deviation of 294 microseconds in 36 samples.

Signed-off-by: Peter Senna Tschudin <peter.senna@collabora.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-11 21:36:43 +02:00
..
8250 Merge 4.11-rc5 into tty-next 2017-04-03 14:18:16 +02:00
cpm_uart tty: serial: cpm_uart: make use of for_each_node_by_type() 2017-02-03 10:12:16 +01:00
jsm tty: serial: jsm_tty: constify uart_ops structures 2016-09-02 15:01:16 +02:00
21285.c
altera_jtaguart.c serial: altera_jtaguart: add earlycon support 2017-03-17 14:14:00 +09:00
altera_uart.c serial: altera_uart: add earlycon support 2017-03-31 16:56:10 +02:00
amba-pl010.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
amba-pl011.c tty: amba-pl011: Fix spurious TX interrupts 2017-04-08 18:54:07 +02:00
amba-pl011.h
apbuart.c
apbuart.h
ar933x_uart.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
arc_uart.c serial/arc: constify uart_ops structures 2016-09-01 21:05:41 +02:00
atmel_serial.c Merge 4.11-rc5 into tty-next 2017-04-03 14:18:16 +02:00
atmel_serial.h tty/serial: atmel: move atmel_serial header into driver directory 2017-03-14 10:59:04 +08:00
bcm63xx_uart.c serial/bcm63xx_uart: constify uart_ops structures 2016-09-02 15:01:16 +02:00
bfin_sport_uart.c tty: serial: constify dev_pm_ops structures 2017-01-19 14:20:23 +01:00
bfin_sport_uart.h
bfin_uart.c
clps711x.c serial: clps711x: Changing the compatibility string to match with the smallest supported chip 2016-07-06 17:38:16 +02:00
crisv10.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
crisv10.h
digicolor-usart.c tty/serial: digicolor: Fix bad usage of IS_ERR_VALUE 2016-02-14 17:39:36 -08:00
dz.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
dz.h
earlycon-arm-semihost.c tty/serial: mark __init early_smh_setup() static 2016-09-02 15:03:35 +02:00
earlycon.c ACPI: parse SPCR and enable matching console 2016-09-28 17:46:46 +02:00
efm32-uart.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
etraxfs-uart.c
fsl_lpuart.c tty: serial: fsl_lpuart: lock port on console write 2017-03-31 16:56:10 +02:00
icom.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
icom.h
ifx6x60.c serial: ifx6x60: Free memory when probe fails 2016-11-10 14:50:46 +01:00
ifx6x60.h
imx.c imx-serial: Reduce RX DMA startup latency when opening for reading 2017-04-11 21:36:43 +02:00
ioc3_serial.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
ioc4_serial.c scripts/spelling.txt: add "comsume(r)" pattern and fix typo instances 2017-02-27 18:43:47 -08:00
ip22zilog.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
ip22zilog.h
Kconfig serial: altera_uart: add earlycon support 2017-03-31 16:56:10 +02:00
kgdb_nmi.c
kgdboc.c
lantiq.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
lpc32xx_hs.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
m32r_sio_reg.h
m32r_sio.c serial: m32r_sio: make it explicitly non-modular 2016-06-25 14:00:06 -07:00
Makefile tty: serial: Makefile: move kgdb to be initialized last 2016-10-27 16:27:24 +02:00
max310x.c serial: max310x: Add support for newer silicon revisions 2017-01-12 11:51:24 +01:00
max3100.c tty: serial: constify uart_ops structures 2016-09-02 15:01:16 +02:00
mcf.c
men_z135_uart.c tty: serial: constify uart_ops structures 2016-09-02 15:01:16 +02:00
meson_uart.c tty: serial: meson: allow baud-rates higher than 115200 2017-01-19 14:38:57 +01:00
mpc52xx_uart.c tty: serial: constify psc_ops structs 2016-02-06 22:31:47 -08:00
mps2-uart.c serial: mps2-uart: make driver explicitly non-modular 2016-06-25 14:01:57 -07:00
mpsc.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
msm_serial.c tty: serial: msm: Fix module autoload 2017-01-12 11:51:25 +01:00
mux.c
mvebu-uart.c serial: mvebu-uart: free the IRQ in ->shutdown() 2016-06-25 14:00:06 -07:00
mxs-auart.c serial: mxs-auart: Fix baudrate calculation 2017-03-31 17:26:19 +02:00
netx-serial.c
omap-serial.c serial: omap: suspend device on probe errors 2017-04-11 21:36:43 +02:00
pch_uart.c serial: pch_uart: add terminate entry for dmi_system_id tables 2016-10-27 16:01:31 +02:00
pic32_uart.c serial: pic32_uart: Fix 'request_irq' and 'free_irq' inconsistancy 2017-01-12 11:51:24 +01:00
pic32_uart.h serial: pic32_uart: Add PIC32 UART driver 2016-05-13 14:01:56 +02:00
pmac_zilog.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
pmac_zilog.h
pnx8xxx_uart.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
pxa.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
rp2.c
sa1100.c
samsung.c serial: samsung: Remove useless spinlock 2017-04-08 18:58:52 +02:00
samsung.h serial: samsung: Simplify DMA engine initialization code 2017-01-12 11:51:24 +01:00
sb1250-duart.c drivers: convert sbd_duart.map_guard from atomic_t to refcount_t 2017-03-14 11:01:40 +08:00
sc16is7xx.c sched/headers: Prepare for new header dependencies before moving code to <uapi/linux/sched/types.h> 2017-03-02 08:42:27 +01:00
sccnxp.c
serial_core.c serial: core: Re-use struct uart_port {name} field 2017-04-08 18:51:57 +02:00
serial_ks8695.c serial: Fix ASYNC_* => UPF_* flags misuse 2016-01-28 14:17:42 -08:00
serial_mctrl_gpio.c serial: mctrl_gpio: enable API usage only for initialized mctrl_gpios struct 2016-06-25 14:30:42 -07:00
serial_mctrl_gpio.h serial: mctrl_gpio: add modem control read routine 2016-06-25 14:30:42 -07:00
serial_txx9.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
serial-tegra.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
sh-sci.c serial: sh-sci: Fix (AUTO)RTS in sci_init_pins() 2017-03-31 15:29:06 +02:00
sh-sci.h serial: sh-sci: consider DR (data ready) bit adequately 2017-02-03 10:14:10 +01:00
sirfsoc_uart.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
sirfsoc_uart.h serial: sirf: make fifo functions static 2016-06-25 14:01:57 -07:00
sn_console.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
sprd_serial.c serial: sprd: adjust TIMEOUT to a big value 2017-04-08 18:42:47 +02:00
st-asc.c serial: st-asc: Change default baudrate from 9600 to 115200 2017-03-31 15:29:05 +02:00
stm32-usart.c serial: stm32: mark symbols static where possible 2016-09-27 12:55:27 +02:00
stm32-usart.h serial: stm32: Fix comparisons with undefined register 2016-10-27 16:00:31 +02:00
suncore.c
sunhv.c sparc64: Send break twice from console to return to boot prom 2017-02-23 08:27:24 -08:00
sunsab.c
sunsab.h
sunsu.c serial: sunsu: Free memory when probe fails 2016-11-16 10:57:26 +01:00
sunzilog.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
sunzilog.h
tilegx.c
timbuart.c tty: serial: constify uart_ops structures 2016-09-02 15:01:16 +02:00
timbuart.h
uartlite.c uartlite: Adding a kernel parameter for the number of uartlites 2017-03-17 14:14:30 +09:00
ucc_uart.c QE-UART: add "fsl,t1040-ucc-uart" to of_device_id 2016-05-01 13:55:12 -07:00
vr41xx_siu.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
vt8500_serial.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
xilinx_uartps.c serial: xuartps: Enable clocks in the pm disable case also 2017-04-08 18:54:07 +02:00
zs.c tty: serial: constify uart_ops structures 2017-01-27 09:23:36 +01:00
zs.h