OpenCloudOS-Kernel/drivers
Serge Semin e8ee6c8cb6 dmaengine: dw: Add DMA-channels mask cell support
DW DMA IP-core provides a way to synthesize the DMA controller with
channels having different parameters like maximum burst-length,
multi-block support, maximum data width, etc. Those parameters both
explicitly and implicitly affect the channels performance. Since DMA slave
devices might be very demanding to the DMA performance, let's provide a
functionality for the slaves to be assigned with DW DMA channels, which
performance according to the platform engineer fulfill their requirements.
After this patch is applied it can be done by passing the mask of suitable
DMA-channels either directly in the dw_dma_slave structure instance or as
a fifth cell of the DMA DT-property. If mask is zero or not provided, then
there is no limitation on the channels allocation.

For instance Baikal-T1 SoC is equipped with a DW DMAC engine, which first
two channels are synthesized with max burst length of 16, while the rest
of the channels have been created with max-burst-len=4. It would seem that
the first two channels must be faster than the others and should be more
preferable for the time-critical DMA slave devices. In practice it turned
out that the situation is quite the opposite. The channels with
max-burst-len=4 demonstrated a better performance than the channels with
max-burst-len=16 even when they both had been initialized with the same
settings. The performance drop of the first two DMA-channels made them
unsuitable for the DW APB SSI slave device. No matter what settings they
are configured with, full-duplex SPI transfers occasionally experience the
Rx FIFO overflow. It means that the DMA-engine doesn't keep up with
incoming data pace even though the SPI-bus is enabled with speed of 25MHz
while the DW DMA controller is clocked with 50MHz signal. There is no such
problem has been noticed for the channels synthesized with
max-burst-len=4.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200731200826.9292-6-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-08-17 11:58:31 +05:30
..
accessibility TTY/Serial patches for 5.9-rc1 2020-08-06 14:56:11 -07:00
acpi More ACPI updates for 5.9-rc1 2020-08-15 08:18:22 -07:00
amba
android
ata
atm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -07:00
auxdisplay Minor cleanup for auxdisplay: 2020-08-06 18:09:34 -07:00
base More power management updates for 5.9-rc1 2020-08-07 13:13:09 -07:00
bcma bcma: gpio: Use irqchip template 2020-08-02 18:26:51 +03:00
block block-5.9-2020-08-14 2020-08-15 20:36:42 -07:00
bluetooth Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next 2020-07-31 15:11:52 -07:00
bus MIPS upates for v5.9 2020-08-06 10:54:07 -07:00
cdrom
char Linux 5.8 2020-08-11 11:58:31 +10:00
clk More ACPI updates for 5.9-rc1 2020-08-15 08:18:22 -07:00
clocksource - Core Frameworks 2020-08-15 08:09:38 -07:00
connector
counter
cpufreq cpufreq: intel_pstate: Implement passive mode with HWP enabled 2020-08-11 17:29:45 +02:00
cpuidle powerpc updates for 5.9 2020-08-07 10:33:50 -07:00
crypto virtio: fixes, features 2020-08-11 14:34:17 -07:00
dax libnvdimm for 5.9 2020-08-11 10:59:19 -07:00
dca
devfreq PM / devfreq: Fix the wrong end with semicolon 2020-07-30 17:22:58 +09:00
dio
dma dmaengine: dw: Add DMA-channels mask cell support 2020-08-17 11:58:31 +05:30
dma-buf A set of locking fixes and updates: 2020-08-10 19:07:44 -07:00
edac Fixes for ie31200 driver that missed the first pull 2020-08-15 08:25:41 -07:00
eisa
extcon
firewire
firmware uaccess: add force_uaccess_{begin,end} helpers 2020-08-12 10:57:59 -07:00
fpga
fsi
gnss
gpio This is the bulk of GPIO changes for the v5.9 kernel cycle: 2020-08-05 12:56:27 -07:00
gpu pwm: Changes for v5.9-rc1 2020-08-14 16:00:09 -07:00
greybus
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid 2020-08-10 16:33:54 -07:00
hsi
hv hyperv-fixes for 5.9-rc 2020-08-14 13:31:25 -07:00
hwmon pwm: Changes for v5.9-rc1 2020-08-14 16:00:09 -07:00
hwspinlock
hwtracing
i2c More ACPI updates for 5.9-rc1 2020-08-15 08:18:22 -07:00
i3c
ide
idle Remove uninitialized_var() macro for v5.9-rc1 2020-08-04 13:49:43 -07:00
iio
infiniband mm/gup: remove task_struct pointer for all gup code 2020-08-12 10:58:04 -07:00
input Cleanup, SECCOMP_FILTER support, message printing fixes, and other 2020-08-15 18:50:32 -07:00
interconnect Char/Misc driver patches for 5.9-rc1 2020-08-05 11:43:47 -07:00
iommu Merge branch 'akpm' (patches from Andrew) 2020-08-12 11:24:12 -07:00
ipack
irqchip The usual boring updates from the interrupt subsystem: 2020-08-04 18:11:58 -07:00
isdn
leds LEDs changes for 5.9-rc1. 2020-08-05 19:24:27 -07:00
lightnvm
macintosh powerpc updates for 5.9 2020-08-07 10:33:50 -07:00
mailbox iomap: constify ioreadX() iomem argument (as in generic implementation) 2020-08-14 19:56:57 -07:00
mcb
md block-5.9-2020-08-14 2020-08-15 20:36:42 -07:00
media IOMMU Updates for Linux v5.9 2020-08-11 14:13:24 -07:00
memory IOMMU Updates for Linux v5.9 2020-08-11 14:13:24 -07:00
memstick MMC core: 2020-08-05 13:23:24 -07:00
message
mfd - Core Frameworks 2020-08-15 08:09:38 -07:00
misc Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 21:14:30 -07:00
mmc This tree adds the sched_set_fifo*() encapsulation APIs to remove 2020-08-06 11:55:43 -07:00
most drivers: most: add USB adapter driver 2020-07-31 14:38:12 +02:00
mtd This pull request contains changes for JFFS2, UBI and UBIFS 2020-08-10 18:20:04 -07:00
mux
net rtl818x: constify ioreadX() iomem argument (as in generic implementation) 2020-08-14 19:56:57 -07:00
nfc
ntb ntb: intel: constify ioreadX() iomem argument (as in generic implementation) 2020-08-14 19:56:57 -07:00
nubus
nvdimm mm: add thp_size 2020-08-14 19:56:56 -07:00
nvme for-5.9/block-merge-20200804 2020-08-05 11:12:34 -07:00
nvmem
of MIPS upates for v5.9 2020-08-06 10:54:07 -07:00
opp Merge branch 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm 2020-08-04 12:44:53 +02:00
oprofile
parisc Merge branch 'parisc-5.9-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux 2020-08-12 12:41:15 -07:00
parport
pci pci-v5.9-changes 2020-08-07 18:48:15 -07:00
pcmcia
perf It looks like a smaller batch of clk updates this time around. In the core 2020-08-07 13:35:51 -07:00
phy
pinctrl This is the bulk of the pin control changes for the v5.9 2020-08-09 12:52:28 -07:00
platform linux-watchdog 5.9-rc1 tag 2020-08-12 12:13:44 -07:00
pnp
power power supply and reset changes for the v5.9 series 2020-08-07 21:27:37 -07:00
powercap This tree adds the sched_set_fifo*() encapsulation APIs to remove 2020-08-06 11:55:43 -07:00
pps
ps3
ptp ptp: only allow phase values lower than 1 period 2020-08-05 12:06:44 -07:00
pwm pwm: Changes for v5.9-rc1 2020-08-14 16:00:09 -07:00
rapidio rapidio/rio_mport_cdev: use array_size() helper in copy_{from,to}_user() 2020-08-12 10:58:01 -07:00
ras
regulator Merge remote-tracking branch 'regulator/for-5.9' into regulator-next 2020-07-30 23:27:08 +01:00
remoteproc remoteproc updates for v5.9 2020-08-11 11:17:45 -07:00
reset
rpmsg
rtc RTC for 5.9 2020-08-12 17:17:00 -07:00
s390 s390/pkey: remove redundant variable initialization 2020-08-11 18:16:31 +02:00
sbus
scsi SCSI misc on 20200814 2020-08-14 16:01:59 -07:00
sfi
sh iomap: constify ioreadX() iomem argument (as in generic implementation) 2020-08-14 19:56:57 -07:00
siox
slimbus
soc Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 21:14:30 -07:00
soundwire
spi sound updates for 5.9 2020-08-06 14:27:31 -07:00
spmi
ssb Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -07:00
staging pci-v5.9-changes 2020-08-07 18:48:15 -07:00
target SCSI misc on 20200814 2020-08-14 16:01:59 -07:00
tc
tee
thermal - Core Frameworks 2020-08-15 08:09:38 -07:00
thunderbolt thunderbolt: merge fix for kunix_resource changes 2020-08-09 11:06:10 -07:00
tty TTY/Serial patches for 5.9-rc1 2020-08-06 14:56:11 -07:00
uio
usb media updates for v5.9-rc1 2020-08-07 13:00:53 -07:00
vdpa virtio: fixes, features 2020-08-11 14:34:17 -07:00
vfio VFIO updates for v5.9-rc1 2020-08-12 12:09:36 -07:00
vhost virtio: fixes, features 2020-08-11 14:34:17 -07:00
video pwm: Changes for v5.9-rc1 2020-08-14 16:00:09 -07:00
virt
virtio virtio: pci: constify ioreadX() iomem argument (as in generic implementation) 2020-08-14 19:56:57 -07:00
visorbus
vlynq
vme
w1
watchdog linux-watchdog 5.9-rc1 tag 2020-08-12 12:13:44 -07:00
xen xen: branch for v5.9-rc1b 2020-08-14 13:34:37 -07:00
zorro
Kconfig
Makefile