OpenCloudOS-Kernel/drivers
Marc Kleine-Budde 07e7593877
spi: spi-imx: add PIO polling support
The driver supports several modes, one of them is PIO/IRQ
"spi_imx_pio_transfer()". The data is exchanged with the IP core using
PIO, an IRQ is setup to signal empty/full FIFOs and the end of the
transfer. The IRQ and scheduling overhead for short transfers is
significant. Using polling instead of IRQs can be beneficial to reduce
the overall CPU load, especially on small transfer workloads.

On an imx6 single core, a given RX workload of the mcp251xfd driver
results in 40% CPU load. Using polling mode reduces the CPU load to
30%.

This patch adds PIO polling support to the driver. For transfers with
a duration of less than 30 µs the polling mode instead of IRQ based
PIO mode is used. 30 µs seems to be a good compromise, which is used
the by the SPI drivers for the raspberry Pi (spi-bcm2835,
spi-bcm2835), too.

Co-developed-by: David Jander <david@protonic.nl>
Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Link: https://lore.kernel.org/r/20220502175457.1977983-9-mkl@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
2022-05-09 18:18:15 +01:00
..
accessibility
acpi More ACPI updates for 5.18-rc1 2022-03-31 13:08:13 -07:00
amba
android
ata Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
atm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-03-17 13:56:58 -07:00
auxdisplay auxdisplay: lcd2s: Use array size explicitly in lcd2s_gotoxy() 2022-03-18 20:31:14 +01:00
base Device properties code update for 5.18-rc1 2022-03-29 11:30:12 -07:00
bcma Core MTD changes: 2022-03-25 13:35:34 -07:00
block for-5.18/drivers-2022-04-02 2022-04-02 11:03:03 -07:00
bluetooth Bluetooth: ath3k: remove superfluous header files 2022-03-18 17:12:09 +01:00
bus Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
cdrom SCSI misc on 20220324 2022-03-24 19:37:53 -07:00
char Random number generator fixes for Linux 5.18-rc1. 2022-03-31 14:51:34 -07:00
clk A single revert to fix a boot regression seen when clk_put() started 2022-04-03 12:21:14 -07:00
clocksource asm-generic updates for 5.18 2022-03-23 18:03:08 -07:00
comedi
connector
counter Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
cpufreq Merge branch 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm 2022-03-22 12:15:47 +01:00
cpuidle RISC-V CPU Idle Support 2022-03-30 16:17:54 -07:00
crypto virtio: features, fixes 2022-03-31 13:57:15 -07:00
cxl cxl/core/port: Fix NULL but dereferenced coccicheck error 2022-03-22 10:51:17 -07:00
dax dax for 5.18 2022-03-24 18:12:09 -07:00
dca
devfreq
dio
dma dmaengine updates for v5.18-rc1 2022-03-30 10:54:49 -07:00
dma-buf
edac Merge branch 'edac-amd64' into edac-updates-for-v5.18 2022-03-21 10:34:57 +01:00
eisa
extcon
firewire
firmware Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
fpga
fsi
gnss
gpio gpio fixes for v5.18-rc1 2022-04-01 10:26:09 -07:00
gpu xen: branch for v5.18-rc1 2022-03-28 14:32:39 -07:00
greybus
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2022-04-01 10:14:32 -07:00
hsi
hv hyperv-next for 5.18 2022-03-24 12:30:37 -07:00
hwmon Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
hwspinlock
hwtracing Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
i2c Merge branch 'i2c/for-mergewindow' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2022-03-26 12:46:08 -07:00
i3c
idle cpuidle: intel_idle: Drop redundant backslash at line end 2022-03-17 14:32:59 +01:00
iio Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
infiniband SCSI misc on 20220324 2022-03-24 19:37:53 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2022-04-01 10:14:32 -07:00
interconnect
iommu dma-mapping updates for Linux 5.18 2022-03-29 08:50:14 -07:00
ipack
irqchip asm-generic updates for 5.18 2022-03-23 18:03:08 -07:00
isdn mISDN: fix typo "frame to short" -> "frame too short" 2022-03-21 13:26:38 +00:00
leds LED updates for 5.18-rc1. Nothing major here, there are two drivers 2022-03-27 14:09:48 -07:00
macintosh
mailbox
mcb
md - Fix DM integrity shrink crash due to journal entry not being marked 2022-04-01 15:57:27 -07:00
media drm for 5.18-rc1 2022-03-24 16:19:43 -07:00
memory ARM driver updates for 5.18 2022-03-23 18:23:13 -07:00
memstick
message
mfd - New Drivers 2022-03-25 13:56:18 -07:00
misc Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
mmc TTY/Serial driver changes for 5.18-rc1 2022-03-28 13:00:51 -07:00
most
mtd mtd: nand: mtk-ecc: also parse nand-ecc-engine if available 2022-04-27 18:12:43 +02:00
mux
net virtio: features, fixes 2022-03-31 13:57:15 -07:00
nfc spi: Updates for v5.18 2022-03-21 18:33:57 -07:00
ntb
nubus
nvdimm libnvdimm for 5.18 2022-03-30 10:04:11 -07:00
nvme for-5.18/drivers-2022-04-01 2022-04-01 16:26:57 -07:00
nvmem nvmem: brcm_nvram: parse NVRAM content into NVMEM cells 2022-03-18 14:08:36 +01:00
of Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
opp
parisc parisc: Fix CPU affinity for Lasi, WAX and Dino chips 2022-03-29 21:37:12 +02:00
parport parport_pc: Also enable driver for PCI systems 2022-03-18 14:01:41 +01:00
pci pci-v5.18-changes-2 2022-04-02 10:54:52 -07:00
pcmcia
peci
perf RISC-V Patches for the 5.18 Merge Window, Part 1 2022-03-25 10:11:38 -07:00
phy phy: PHY_FSL_LYNX_28G should depend on ARCH_LAYERSCAPE 2022-03-29 08:45:16 -07:00
pinctrl Pin control bulk changes for the v5.18 kernel cycle 2022-03-28 11:52:53 -07:00
platform chrome platform changes for 5.18 2022-04-02 10:44:18 -07:00
pnp PNP update for 5.18-rc1 2022-03-21 14:46:01 -07:00
power Driver core changes for 5.18-rc1 2022-03-28 12:41:28 -07:00
powercap
pps pps: generators: pps_gen_parport: Switch to use module_parport_driver() 2022-03-18 14:01:19 +01:00
ps3
ptp ptp: ocp: handle error from nvmem_device_find 2022-03-30 12:08:11 -07:00
pwm
rapidio
ras
regulator regulator: Fixes for v5.18 2022-03-30 10:58:28 -07:00
remoteproc remoteproc updates for v5.18 2022-03-30 10:50:48 -07:00
reset
rpmsg
rtc RTC for 5.18 2022-04-01 09:37:18 -07:00
s390 s390: cleanup timer API use 2022-03-27 22:18:39 +02:00
sbus
scsi xen: branch for v5.18-rc1 2022-03-28 14:32:39 -07:00
sh
siox
slimbus
soc Networking changes for 5.18. 2022-03-24 13:13:26 -07:00
soundwire Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
spi spi: spi-imx: add PIO polling support 2022-05-09 18:18:15 +01:00
spmi
ssb
staging Staging driver update for 5.18-rc1 2022-03-28 12:50:50 -07:00
target SCSI misc on 20220324 2022-03-24 19:37:53 -07:00
tc
tee ARM driver updates for 5.18 2022-03-23 18:23:13 -07:00
thermal Merge branch 'thermal-hfi' 2022-03-18 19:00:26 +01:00
thunderbolt Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00
tty TTY/Serial driver changes for 5.18-rc1 2022-03-28 13:00:51 -07:00
uio
usb xen: branch for v5.18-rc1 2022-03-28 14:32:39 -07:00
vdpa virtio: features, fixes 2022-03-31 13:57:15 -07:00
vfio
vhost virtio: features, fixes 2022-03-31 13:57:15 -07:00
video Driver core changes for 5.18-rc1 2022-03-28 12:41:28 -07:00
virt Random number generator fixes for Linux 5.18-rc1. 2022-03-31 14:51:34 -07:00
virtio virtio: features, fixes 2022-03-31 13:57:15 -07:00
visorbus
vlynq
vme
w1 w1: w1_therm: Add support for Maxim MAX31850 thermoelement IF. 2022-03-18 14:07:09 +01:00
watchdog linux-watchdog 5.18-rc1 tag 2022-03-31 14:14:03 -07:00
xen xen: don't hang when resuming PCI device 2022-03-25 14:22:15 -05:00
zorro
Kconfig
Makefile