linux/drivers/tty/serial
Paul Walmsley edbe5dbefe tty: serial: OMAP: block idle while the UART is transferring data in PIO mode
Prevent OMAP UARTs from going idle while they are still transferring
data in PIO mode.  This works around an oversight in the OMAP UART
hardware present in OMAP34xx and earlier: an idle UART won't send a
wakeup when the TX FIFO threshold is reached.  This causes long delays
during data transmission when the MPU powerdomain enters a low-power
mode.  The MPU interrupt controller is not able to respond to
interrupts when it's in a low-power state, so the TX buffer is not
refilled until another wakeup event occurs.

This fix changes the erratum i291 DMA idle workaround.  Rather than
toggling between force-idle and no-idle, it will toggle between
smart-idle and no-idle.  The important part of the workaround is the
no-idle part, so this shouldn't result in any change in behavior.

This fix should work on all OMAP UARTs.  Future patches intended for
the 3.4 merge window will make this workaround conditional on a
"feature" flag, and will use the OMAP36xx+ TX event wakeup support.

Thanks to Kevin Hilman <khilman@ti.com> for mentioning the erratum i291
workaround, which led to the development of this approach.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-02-02 13:00:15 -08:00
..
cpm_uart TTY: serial, fix includes in some drivers 2011-09-22 15:49:26 -07:00
jsm tty: Add module.h to drivers/tty users who just expect it there. 2011-10-31 19:31:27 -04:00
8250_accent.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
8250_acorn.c
8250_boca.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
8250_dw.c TTY: serial: convert drivers/tty/serial/* to use module_platform_driver() 2011-11-30 20:11:46 +09:00
8250_early.c
8250_exar_st16c554.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
8250_fourport.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
8250_fsl.c serial: add irq handler for Freescale 16550 errata. 2011-12-09 19:14:13 -08:00
8250_gsc.c
8250_hp300.c
8250_hub6.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
8250_mca.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
8250_pci.c serial: add support for 400 and 800 v3 series Titan cards 2012-01-03 16:46:10 -08:00
8250_pnp.c serial: 8250_pnp: add Intermec CV60 touchscreen device 2011-08-22 14:18:44 -07:00
8250.c serial: Kill off NO_IRQ 2012-01-26 17:14:50 -08:00
8250.h serial: move struct uart_8250_port from 8250.c to 8250.h 2011-12-09 19:14:12 -08:00
21285.c serial: Kill off NO_IRQ 2012-01-26 17:14:50 -08:00
68328serial.c TTY: irq: Remove IRQF_DISABLED 2011-09-22 16:08:57 -07:00
68328serial.h TTY: serial, remove dead code from 68328 2011-09-22 15:47:54 -07:00
altera_jtaguart.c Merge branch 'devicetree/next' of git://git.secretlab.ca/git/linux-2.6 2011-10-27 08:35:41 +02:00
altera_uart.c Merge branch 'devicetree/next' of git://git.secretlab.ca/git/linux-2.6 2011-10-27 08:35:41 +02:00
amba-pl010.c serial: pl010: Enable module alias autogeneration for AMBA drivers 2011-11-22 10:58:32 +00:00
amba-pl011.c Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2012-01-17 18:40:24 -08:00
apbuart.c apbuart: fix section mismatch warning 2011-12-27 16:33:13 -05:00
apbuart.h
ar933x_uart.c SERIAL: AR933X: Add driver for the built-in UART of the SoC 2011-12-07 22:02:46 +00:00
atmel_serial.c atmel_serial: fix spinlock lockup in RS485 code 2012-01-04 16:19:34 -08:00
bcm63xx_uart.c serial: bcm63xx_uart: fix irq storm after rx fifo overrun. 2011-06-16 12:01:58 -07:00
bfin_sport_uart.c serial: bfin-sport-uart: Add tty ASYNC_CTS_FLOW flag to do CTS flow control. 2011-12-09 19:05:33 -08:00
bfin_sport_uart.h tty: bfin-sport-uart: Rx interrupt is not called always with irq disabled. 2011-12-09 19:05:33 -08:00
bfin_uart.c serial: bfin-uart: Remove ASYNC_CTS_FLOW flag for hardware automatic CTS. 2011-12-13 09:50:15 -08:00
clps711x.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
crisv10.c RS485: fix inconsistencies in the meaning of some variables 2011-11-15 12:13:44 -08:00
crisv10.h
dz.c TTY: serial, fix includes in some drivers 2011-09-22 15:49:26 -07:00
dz.h
efm32-uart.c serial/efm32: add new driver 2012-01-26 11:29:47 -08:00
icom.c TTY: irq: Remove IRQF_DISABLED 2011-09-22 16:08:57 -07:00
icom.h
ifx6x60.c TTY: Remove redundant spi driver bus initialization 2011-11-26 20:19:21 -08:00
ifx6x60.h serial: ifx6x60: minor cleanup 2011-02-17 11:16:15 -08:00
imx.c tty: serial: imx: move del_timer_sync() to avoid potential deadlock 2012-01-04 16:30:36 -08:00
ioc3_serial.c TTY: serial, fix includes in some drivers 2011-09-22 15:49:26 -07:00
ioc4_serial.c TTY: serial, fix includes in some drivers 2011-09-22 15:49:26 -07:00
ip22zilog.c Fix common misspellings 2011-03-31 11:26:23 -03:00
ip22zilog.h
Kconfig serial/efm32: add new driver 2012-01-26 11:29:47 -08:00
kgdboc.c tty: Add module.h to drivers/tty users who just expect it there. 2011-10-31 19:31:27 -04:00
lantiq.c Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty 2011-10-26 15:11:09 +02:00
m32r_sio_reg.h
m32r_sio.c serial: Kill off NO_IRQ 2012-01-26 17:14:50 -08:00
m32r_sio.h
Makefile serial/efm32: add new driver 2012-01-26 11:29:47 -08:00
max3100.c TTY: Remove redundant spi driver bus initialization 2011-11-26 20:19:21 -08:00
max3107-aava.c TTY: Remove redundant spi driver bus initialization 2011-11-26 20:19:21 -08:00
max3107.c TTY: Remove redundant spi driver bus initialization 2011-11-26 20:19:21 -08:00
max3107.h Fix common misspellings 2011-03-31 11:26:23 -03:00
mcf.c TTY: irq: Remove IRQF_DISABLED 2011-09-22 16:08:57 -07:00
mfd.c Merge 3.2-rc3 into tty-next to handle merge conflict in tty_ldisc.c 2011-11-26 20:07:25 -08:00
mpc52xx_uart.c serial: Kill off NO_IRQ 2012-01-26 17:14:50 -08:00
mpsc.c
mrst_max3110.c TTY: Remove redundant spi driver bus initialization 2011-11-26 20:19:21 -08:00
mrst_max3110.h max3110: add sysrq support 2011-08-26 11:01:15 -07:00
msm_serial_hs.c msm_serial_hs: Fix spinlock recursion in handling CTS 2011-12-09 19:10:04 -08:00
msm_serial.c Merge branch 'next/dt' of git://git.linaro.org/people/arnd/arm-soc 2011-11-01 21:02:35 -07:00
msm_serial.h tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
msm_smd_tty.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
mux.c serial: Kill off NO_IRQ 2012-01-26 17:14:50 -08:00
mxs-auart.c clock management changes for i.MX 2012-01-09 14:44:15 -08:00
netx-serial.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
nwpserial.c tty: Add export.h for EXPORT_SYMBOL/THIS_MODULE to exporters 2011-10-31 19:31:28 -04:00
of_serial.c drivercore: Add helper macro for platform_driver boilerplate 2011-10-25 00:35:47 +02:00
omap-serial.c tty: serial: OMAP: block idle while the UART is transferring data in PIO mode 2012-02-02 13:00:15 -08:00
pch_uart.c Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2012-01-17 18:40:24 -08:00
pmac_zilog.c serial: Kill off NO_IRQ 2012-01-26 17:14:50 -08:00
pmac_zilog.h tty/serial/pmac_zilog: Fix suspend & resume 2011-12-16 11:10:01 +11:00
pnx8xxx_uart.c
pxa.c serial: pxa: work around for errata #20 2011-09-22 15:47:53 -07:00
sa1100.c tty: remove invalid location line in file header 2011-04-19 16:33:36 -07:00
samsung.c serial: samsung: Fix build for non-Exynos4210 devices 2011-12-23 10:07:01 +09:00
samsung.h serial: samsung: merge probe() function from all SoC specific extensions 2011-12-23 10:07:00 +09:00
sb1250-duart.c TTY: serial, fix includes in some drivers 2011-09-22 15:49:26 -07:00
sc26xx.c TTY: serial: convert drivers/tty/serial/* to use module_platform_driver() 2011-11-30 20:11:46 +09:00
serial_core.c serial: use DIV_ROUND_CLOSEST instead of open coding it 2012-01-04 16:18:54 -08:00
serial_cs.c serial: fix serial_cs I/O windows for Argosy RS-COM 2P 2011-12-09 19:07:46 -08:00
serial_ks8695.c TTY: irq: Remove IRQF_DISABLED 2011-09-22 16:08:57 -07:00
serial_txx9.c TTY: serial, fix includes in some drivers 2011-09-22 15:49:26 -07:00
sh-sci.c Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2012-01-17 18:40:24 -08:00
sh-sci.h ARM: mach-shmobile: R-Mobile A1 support. 2011-11-11 16:55:31 +09:00
sirfsoc_uart.c UART: add CSR SiRFprimaII SoC on-chip uart drivers 2011-11-17 11:46:04 -08:00
sirfsoc_uart.h UART: add CSR SiRFprimaII SoC on-chip uart drivers 2011-11-17 11:46:04 -08:00
sn_console.c TTY: irq: Remove IRQF_DISABLED 2011-09-22 16:08:57 -07:00
suncore.c
suncore.h
sunhv.c dt/serial: Eliminate users of of_platform_{,un}register_driver 2011-02-28 13:22:46 -07:00
sunsab.c dt/serial: Eliminate users of of_platform_{,un}register_driver 2011-02-28 13:22:46 -07:00
sunsab.h
sunsu.c treewide: Convert uses of struct resource to resource_size(ptr) 2011-06-10 14:55:36 +02:00
sunzilog.c serial: Kill off NO_IRQ 2012-01-26 17:14:50 -08:00
sunzilog.h
timbuart.c TTY: serial: convert drivers/tty/serial/* to use module_platform_driver() 2011-11-30 20:11:46 +09:00
timbuart.h
uartlite.c Merge branch 'devicetree/next' of git://git.secretlab.ca/git/linux-2.6 2011-10-27 08:35:41 +02:00
ucc_uart.c serial: Kill off NO_IRQ 2012-01-26 17:14:50 -08:00
vr41xx_siu.c serial: Kill off NO_IRQ 2012-01-26 17:14:50 -08:00
vt8500_serial.c treewide: Convert uses of struct resource to resource_size(ptr) 2011-06-10 14:55:36 +02:00
xilinx_uartps.c tty: Add module.h to drivers/tty users who just expect it there. 2011-10-31 19:31:27 -04:00
zs.c TTY: serial, fix includes in some drivers 2011-09-22 15:49:26 -07:00
zs.h