- 18 Oct, 2019 2 commits
-
-
Gregory CLEMENT authored
When improving the CS GPIO support at core level, the SPI_CS_HIGH has been enabled for all the CS lines used for a given SPI controller. However, the SPI framework allows to have on the same controller native CS and GPIO CS. The native CS may not support the SPI_CS_HIGH, so they should not be setup automatically. With this patch the setting is done only for the CS that will use a GPIO as CS Fixes: f3186dd8 ("spi: Optionally use GPIO descriptors for CS GPIOs") Cc: <stable@vger.kernel.org> Signed-off-by:
Gregory CLEMENT <gregory.clement@bootlin.com> Link: https://lore.kernel.org/r/20191018152929.3287-1-gregory.clement@bootlin.comSigned-off-by:
Mark Brown <broonie@kernel.org>
-
Daniel Vetter authored
In DMA mode we have a maximum transfer size, past that the driver falls back to PIO (see the check at the top of pxa2xx_spi_transfer_one). Falling back to PIO for big transfers defeats the point of a dma engine, hence set the max transfer size to inform spi clients that they need to do something smarter. This was uncovered by the drm_mipi_dbi spi panel code, which does large spi transfers, but stopped splitting them after: commit e143364b Author: Noralf Trønnes <noralf@tronnes.org> Date: Fri Jul 19 17:59:10 2019 +0200 drm/tinydrm: Remove tinydrm_spi_max_transfer_size() After this commit the code relied on the spi core to split transfers into max dma-able blocks, which also papered over the PIO fallback issue. Fix this by setting the overall max transfer size to the DMA limit, but only when the controller runs in DMA mode. Fixes: e143364b ("drm/tinydrm: Remove tinydrm_spi_max_transfer_size()") Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Noralf Trønnes <noralf@tronnes.org> Cc: Andy Shevchenko <andriy.shevchenko@intel.com> Reported-and-tested-by:
Andy Shevchenko <andriy.shevchenko@intel.com> Cc: Daniel Mack <daniel@zonque.org> Cc: Haojian Zhuang <haojian.zhuang@gmail.com> Cc: Robert Jarzmik <robert.jarzmik@free.fr> Cc: Mark Brown <broonie@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-spi@vger.kernel.org Signed-off-by:
Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://lore.kernel.org/r/20191017064426.30814-1-daniel.vetter@ffwll.chSigned-off-by:
-
- 08 Oct, 2019 2 commits
-
-
Frieder Schrempf authored
Later versions of the QSPI controller (e.g. in i.MX6UL/ULL and i.MX7) seem to have an additional TDH setting in the FLSHCR register, that needs to be set in accordance with the access mode that is used (DDR or SDR). Previous bootstages such as BootROM or bootloader might have used the DDR mode to access the flash. As we currently only use SDR mode, we need to make sure the TDH bits are cleared upon initialization. Fixes: 84d04318 ("spi: Add a driver for the Freescale/NXP QuadSPI controller") Cc: <stable@vger.kernel.org> Signed-off-by:
Frieder Schrempf <frieder.schrempf@kontron.de> Acked-by:
Han Xu <han.xu@nxp.com> Link: https://lore.kernel.org/r/20191007071933.26786-1-frieder.schrempf@kontron.deSigned-off-by:
-
Vladimir Oltean authored
With this patch, the "interrupts" property from the device tree bindings is ignored, even if present, if the driver runs in TCFQ mode. Switching to using the DSPI in poll mode has several distinct benefits: - With interrupts, the DSPI driver in TCFQ mode raises an IRQ after each transmitted word. There is more time wasted for the "waitq" event than for actual I/O. And the DSPI IRQ count can easily get the largest in /proc/interrupts on Freescale boards with attached SPI devices. - The SPI I/O time is both lower, and more consistently so. Attached to some Freescale devices are either PTP switches, or SPI RTCs. For reading time off of a SPI slave device, it is important that all SPI transfers take a deterministic time to complete. - In poll mode there is much less time spent by the CPU in hardirq context, which helps with the response latency of the system, and at the same time there is more control over when interrupts must be disabled (to get a precise timestamp measurement): win-win. On the LS1021A-TSN board, where the SPI device is a SJA1105 PTP switch (with a bits_per_word=8 driver), I created a "benchmark" where I read its PTP time once per second, for 120 seconds. Each "read PTP time" is a 12-byte SPI transfer. I then recorded the time before putting the first byte in the TX FIFO, and the time after reading the last byte from the RX FIFO. That is the transfer delay in nanoseconds. Interrupt mode: delay: min 125120 max 168320 mean 150286 std dev 17675.3 Poll mode: delay: min 69440 max 119040 mean 70312.9 std dev 8065.34 Both the mean latency and the standard deviation are more than 50% lower in poll mode than in interrupt mode. This is with an 'ondemand' governor on an otherwise idle system - therefore running mostly at 600 MHz out of a max of 1200 MHz. Signed-off-by:
Vladimir Oltean <olteanv@gmail.com> Link: https://lore.kernel.org/r/20190905010114.26718-5-olteanv@gmail.comSigned-off-by:
-
- 04 Oct, 2019 1 commit
-
-
Patrice Chotard authored
spi_master_put() must only be called in .probe() in case of error. As devm_spi_register_master() is used during probe, spi_master_put() mustn't be called in .remove() callback. It fixes the following kernel WARNING/Oops when executing echo "58003000.spi" > /sys/bus/platform/drivers/stm32-qspi/unbind : ------------[ cut here ]------------ WARNING: CPU: 1 PID: 496 at fs/kernfs/dir.c:1504 kernfs_remove_by_name_ns+0x9c/0xa4 kernfs: can not remove 'uevent', no directory Modules linked in: CPU: 1 PID: 496 Comm: sh Not tainted 5.3.0-rc1-00219-ga0e07bb51a37 #62 Hardware name: STM32 (Device Tree Support) [<c0111570>] (unwind_backtrace) from [<c010d384>] (show_stack+0x10/0x14) [<c010d384>] (show_stack) from [<c08db558>] (dump_stack+0xb4/0xc8) [<c08db558>] (dump_stack) from [<c01209d8>] (__warn.part.3+0xbc/0xd8) [<c01209d8>] (__warn.part.3) from [<c0120a5c>] (warn_slowpath_fmt+0x68/0x8c) [<c0120a5c>] (warn_slowpath_fmt) from [<c02e5844>] (kernfs_remove_by_name_ns+0x9c/0xa4) [<c02e5844>] (kernfs_remove_by_name_ns) from [<c05833a4>] (device_del+0x128/0x358) [<c05833a4>] (device_del) from [<c05835f8>] (device_unregister+0x24/0x64) [<c05835f8>] (device_unregister) from [<c0638dac>] (spi_unregister_controller+0x88/0xe8) [<c0638dac>] (spi_unregister_controller) from [<c058c580>] (release_nodes+0x1bc/0x200) [<c058c580>] (release_nodes) from [<c0588a44>] (device_release_driver_internal+0xec/0x1ac) [<c0588a44>] (device_release_driver_internal) from [<c0586840>] (unbind_store+0x60/0xd4) [<c0586840>] (unbind_store) from [<c02e64e8>] (kernfs_fop_write+0xe8/0x1c4) [<c02e64e8>] (kernfs_fop_write) from [<c0266b44>] (__vfs_write+0x2c/0x1c0) [<c0266b44>] (__vfs_write) from [<c02694c0>] (vfs_write+0xa4/0x184) [<c02694c0>] (vfs_write) from [<c0269710>] (ksys_write+0x58/0xd0) [<c0269710>] (ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x54) Exception stack(0xdd289fa8 to 0xdd289ff0) 9fa0: 0000006c 000e20e8 00000001 000e20e8 0000000d 00000000 9fc0: 0000006c 000e20e8 b6f87da0 00000004 0000000d 0000000d 00000000 00000000 9fe0: 00000004 bee639b0 b6f2286b b6eaf6c6 ---[ end trace 1b15df8a02d76aef ]--- ------------[ cut here ]------------ WARNING: CPU: 1 PID: 496 at fs/kernfs/dir.c:1504 kernfs_remove_by_name_ns+0x9c/0xa4 kernfs: can not remove 'online', no directory Modules linked in: CPU: 1 PID: 496 Comm: sh Tainted: G W 5.3.0-rc1-00219-ga0e07bb51a37 #62 Hardware name: STM32 (Device Tree Support) [<c0111570>] (unwind_backtrace) from [<c010d384>] (show_stack+0x10/0x14) [<c010d384>] (show_stack) from [<c08db558>] (dump_stack+0xb4/0xc8) [<c08db558>] (dump_stack) from [<c01209d8>] (__warn.part.3+0xbc/0xd8) [<c01209d8>] (__warn.part.3) from [<c0120a5c>] (warn_slowpath_fmt+0x68/0x8c) [<c0120a5c>] (warn_slowpath_fmt) from [<c02e5844>] (kernfs_remove_by_name_ns+0x9c/0xa4) [<c02e5844>] (kernfs_remove_by_name_ns) from [<c0582488>] (device_remove_attrs+0x20/0x5c) [<c0582488>] (device_remove_attrs) from [<c05833b0>] (device_del+0x134/0x358) [<c05833b0>] (device_del) from [<c05835f8>] (device_unregister+0x24/0x64) [<c05835f8>] (device_unregister) from [<c0638dac>] (spi_unregister_controller+0x88/0xe8) [<c0638dac>] (spi_unregister_controller) from [<c058c580>] (release_nodes+0x1bc/0x200) [<c058c580>] (release_nodes) from [<c0588a44>] (device_release_driver_internal+0xec/0x1ac) [<c0588a44>] (device_release_driver_internal) from [<c0586840>] (unbind_store+0x60/0xd4) [<c0586840>] (unbind_store) from [<c02e64e8>] (kernfs_fop_write+0xe8/0x1c4) [<c02e64e8>] (kernfs_fop_write) from [<c0266b44>] (__vfs_write+0x2c/0x1c0) [<c0266b44>] (__vfs_write) from [<c02694c0>] (vfs_write+0xa4/0x184) [<c02694c0>] (vfs_write) from [<c0269710>] (ksys_write+0x58/0xd0) [<c0269710>] (ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x54) Exception stack(0xdd289fa8 to 0xdd289ff0) 9fa0: 0000006c 000e20e8 00000001 000e20e8 0000000d 00000000 9fc0: 0000006c 000e20e8 b6f87da0 00000004 0000000d 0000000d 00000000 00000000 9fe0: 00000004 bee639b0 b6f2286b b6eaf6c6 ---[ end trace 1b15df8a02d76af0 ]--- 8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 00000050 pgd = e612f14d [00000050] *pgd=ff1f5835 Internal error: Oops: 17 [#1] SMP ARM Modules linked in: CPU: 1 PID: 496 Comm: sh Tainted: G W 5.3.0-rc1-00219-ga0e07bb51a37 #62 Hardware name: STM32 (Device Tree Support) PC is at kernfs_find_ns+0x8/0xfc LR is at kernfs_find_and_get_ns+0x30/0x48 pc : [<c02e49a4>] lr : [<c02e4ac8>] psr: 40010013 sp : dd289dac ip : 00000000 fp : 00000000 r10: 00000000 r9 : def6ec58 r8 : dd289e54 r7 : 00000000 r6 : c0abb234 r5 : 00000000 r4 : c0d26a30 r3 : ddab5080 r2 : 00000000 r1 : c0abb234 r0 : 00000000 Flags: nZcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 10c5387d Table: dd11c06a DAC: 00000051 Process sh (pid: 496, stack limit = 0xe13a592d) Stack: (0xdd289dac to 0xdd28a000) 9da0: c0d26a30 00000000 c0abb234 00000000 c02e4ac8 9dc0: 00000000 c0976b44 def6ec00 dea53810 dd289e54 c02e864c c0a61a48 c0a4a5ec 9de0: c0d630a8 def6ec00 c0d04c48 c02e86e0 def6ec00 de909338 c0d04c48 c05833b0 9e00: 00000000 c0638144 dd289e54 def59900 00000000 475b3ee5 def6ec00 00000000 9e20: def6ec00 def59b80 dd289e54 def59900 00000000 c05835f8 def6ec00 c0638dac 9e40: 0000000a dea53810 c0d04c48 c058c580 dea53810 def59500 def59b80 475b3ee5 9e60: ddc63e00 dea53810 dea3fe10 c0d63a0c dea53810 ddc63e00 dd289f78 dd240d10 9e80: 00000000 c0588a44 c0d59a20 0000000d c0d63a0c c0586840 0000000d dd240d00 9ea0: 00000000 00000000 ddc63e00 c02e64e8 00000000 00000000 c0d04c48 dd9bbcc0 9ec0: c02e6400 dd289f78 00000000 000e20e8 0000000d c0266b44 00000055 00000cc0 9ee0: 000000e3 000e3000 dd11c000 dd11c000 00000000 00000000 00000000 00000000 9f00: ffeee38c dff99688 00000000 475b3ee5 00000001 dd289fb0 ddab5080 ddaa5800 9f20: 00000817 000e30ec dd9e7720 475b3ee5 ddaa583c 0000000d dd9bbcc0 000e20e8 9f40: dd289f78 00000000 000e20e8 0000000d 00000000 c02694c0 00000000 00000000 9f60: c0d04c48 dd9bbcc0 00000000 00000000 dd9bbcc0 c0269710 00000000 00000000 9f80: 000a91f4 475b3ee5 0000006c 000e20e8 b6f87da0 00000004 c0101204 dd288000 9fa0: 00000004 c0101000 0000006c 000e20e8 00000001 000e20e8 0000000d 00000000 9fc0: 0000006c 000e20e8 b6f87da0 00000004 0000000d 0000000d 00000000 00000000 9fe0: 00000004 bee639b0 b6f2286b b6eaf6c6 600e0030 00000001 00000000 00000000 [<c02e49a4>] (kernfs_find_ns) from [<def6ec00>] (0xdef6ec00) Code: ebf8eeab c0dc50b8 e92d40f0 e292c000 (e1d035b0) ---[ end trace 1b15df8a02d76af1 ]--- Fixes: a88eceb1 ("spi: stm32-qspi: add spi_master_put in release function") Cc: <stable@vger.kernel.org> Signed-off-by:
Patrice Chotard <patrice.chotard@st.com> Link: https://lore.kernel.org/r/20191004123606.17241-1-patrice.chotard@st.comSigned-off-by:
-
- 01 Oct, 2019 2 commits
-
-
Navid Emamdoost authored
In fsl_lpspi_probe an SPI controller is allocated either via spi_alloc_slave or spi_alloc_master. In all but one error cases this controller is put by going to error handling code. This commit fixes the case when pm_runtime_get_sync fails and it should go to the error handling path. Fixes: 944c01a8 ("spi: lpspi: enable runtime pm for lpspi") Signed-off-by:
Navid Emamdoost <navid.emamdoost@gmail.com> Link: https://lore.kernel.org/r/20190930034602.1467-1-navid.emamdoost@gmail.comSigned-off-by:
-
Navid Emamdoost authored
In spi_gpio_probe an SPI master is allocated via spi_alloc_master, but this controller should be released if devm_add_action_or_reset fails, otherwise memory leaks. In order to avoid leak spi_contriller_put must be called in case of failure for devm_add_action_or_reset. Fixes: 8b797490 ("spi: gpio: Make sure spi_master_put() is called in every error path") Signed-off-by:
-
- 26 Sep, 2019 1 commit
-
-
tomaspaukrt@email.cz authored
The current initialisation of runtime PM in the orion-spi.c driver is incorrect, because calling pm_runtime_put_autosuspend before calling pm_runtime_get leads to a negative value of the reference count and therefore it sometimes causes suspend during a transmission. Signed-off-by:
Tomas Paukrt <tomaspaukrt@email.cz> Link: https://lore.kernel.org/r/E2A.ZWgn.6sH16TohXKE.1TYpoi@seznam.czSigned-off-by:
-
- 25 Sep, 2019 1 commit
-
-
Lukasz Majewski authored
This change is necessary for spidev devices (e.g. /dev/spidev3.0) working in the slave mode (like NXP's dspi driver for Vybrid SoC). When SPI HW works in this mode - the master is responsible for providing CS and CLK signals. However, when some fault happens - like for example distortion on SPI lines - the SPI Linux driver needs a chance to recover from this abnormal situation and prepare itself for next (correct) transmission. This change doesn't pose any threat on drivers working in master mode as spi_slave_abort() function checks if SPI slave mode is supported. Signed-off-by:
Lukasz Majewski <lukma@denx.de> Link: https://lore.kernel.org/r/20190924110547.14770-2-lukma@denx.deSigned-off-by:
kbuild test robot <lkp@intel.com> Link: https://lore.kernel.org/r/20190925091143.15468-2-lukma@denx.deSigned-off-by:
-
- 20 Sep, 2019 2 commits
-
-
Miquel Raynal authored
Fix the current layout which only matches early non-public revisions of the IP. Since its official distribution, two bytes of the SPI controller DMAS_CTRL register have been inverted. Suggested-by:
Mason Yang <masonccyang@mxic.com.tw> Signed-off-by:
Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20190919202504.9619-4-miquel.raynal@bootlin.comSigned-off-by:
-
Miquel Raynal authored
The SPI_NAND bit is a (wrongly named) placeholder that is intended to be used in the future. Right now SPI_NOR (which is currently identical to SPI_NAND in this version of the IP) should be used in both cases. Suggested-by:
-
- 13 Sep, 2019 3 commits
-
-
luhua.xu authored
Add spi large PA(max=64G) support for DMA transfer. Signed-off-by:
luhua.xu <luhua.xu@mediatek.com> Link: https://lore.kernel.org/r/1568195731-3239-4-git-send-email-luhua.xu@mediatek.comSigned-off-by:
-
luhua.xu authored
This patch add spi support for mt6765 IC. Signed-off-by:
-
luhua.xu authored
Add a DT binding documentation for the MT6765 soc. Signed-off-by:
-
- 11 Sep, 2019 9 commits
-
-
Lukas Wunner authored
The BCM2835 SPI driver currently sets the SPI_CONTROLLER_MUST_TX flag. When performing an RX-only transfer, this flag causes the SPI core to allocate and DMA-map a dummy buffer which is copied to the TX FIFO. The dummy buffer is necessary because the chip is not capable of automatically clocking out null bytes. Avoid the overhead induced by the dummy buffer by preallocating a reusable DMA transaction which fills the TX FIFO by cyclically copying from the zero page. The transaction requires very little CPU time to submit and generates no interrupts while running. Specifics are provided in kerneldoc comments. [Nathan Chancellor contributed a DMA mapping fixup for an early version of this commit, hence his Signed-off-by.] Tested-by:
Nuno Sá <nuno.sa@analog.com> Tested-by:
Noralf Trønnes <noralf@tronnes.org> Signed-off-by:
Nathan Chancellor <natechancellor@gmail.com> Signed-off-by:
Lukas Wunner <lukas@wunner.de> Acked-by:
Stefan Wahren <wahrenst@gmx.net> Acked-by:
Martin Sperl <kernel@martin.sperl.org> Cc: Robert Jarzmik <robert.jarzmik@free.fr> Link: https://lore.kernel.org/r/f45920af18dbf06e34129bbc406f53dc9c5d1075.1568187525.git.lukas@wunner.deSigned-off-by:
-
Lukas Wunner authored
The BCM2835 SPI driver currently sets the SPI_CONTROLLER_MUST_RX flag. When performing a TX-only transfer, this flag causes the SPI core to allocate and DMA-map a dummy buffer into which the RX FIFO contents are copied. The dummy buffer is necessary because the chip is not capable of disabling the receiver or automatically throwing away received data. Not reading the RX FIFO isn't an option either since transmission is halted once it's full. Avoid the overhead induced by the dummy buffer by preallocating a reusable DMA transaction which cyclically clears the RX FIFO. The transaction requires very little CPU time to submit and generates no interrupts while running. Specifics are provided in kerneldoc comments. With a ks8851 Ethernet chip attached to the SPI controller, I am seeing a 30 us reduction in ping time with this commit (1.819 ms vs. 1.849 ms, average of 100,000 packets) as well as a 2% reduction in CPU time (75:08 vs. 76:39 for transmission of 5 GByte over the SPI bus). The commit uses the TX DMA interrupt to signal completion of a transfer. This interrupt is raised once all bytes have been written to the TX FIFO and it is then necessary to busy-wait for the TX FIFO to become empty before the transfer can be finalized. As an alternative approach, I have explored using the SPI controller's DONE interrupt to detect completion. This interrupt is signaled when the TX FIFO becomes empty, avoiding the need to busy-wait. However latency deteriorates compared to the present commit and surprisingly, CPU time is slightly higher as well: It turns out that in 45% of the cases, no busy-waiting is needed at all and in 76% of the cases, less than 10 busy-wait iterations are sufficient for the TX FIFO to drain. This was measured on an RT kernel. On a vanilla kernel, wakeup latency is worse and thus fewer iterations are needed. The measurements were made with an SPI clock of 20 MHz, they may differ slightly for slower or faster clock speeds. Previously we always used the RX DMA interrupt to signal completion of a transfer. Using the TX DMA interrupt now introduces a race condition: TX DMA is always started before RX DMA so that bytes are already clocked out while RX DMA is still being set up. But if a TX-only transfer is very short, then the TX DMA interrupt may occur before RX DMA is set up. If the interrupt happens to occur on the same CPU, setup of RX DMA may even be delayed until after the interrupt was handled. I've solved this by having the TX DMA callback clear the RX FIFO while busy-waiting for the TX FIFO to drain, thus avoiding a dependency on setup of RX DMA. Additionally, I am using a lock-free mechanism with two flags, tx_dma_active and rx_dma_active plus memory barriers to terminate RX DMA either by the TX DMA callback or immediately after setting it up, whichever wins the race. I've explored an alternative approach which temporarily disables the TX DMA callback until RX DMA has been set up (using tasklet_disable(), local_bh_disable() or local_irq_save()), but the performance was minimally worse. [Nathan Chancellor contributed a DMA mapping fixup for an early version of this commit, hence his Signed-off-by.] Tested-by:
-
Lukas Wunner authored
The BCM2835 DMA controller is capable of synthesizing zeroes instead of copying them from a source address. The feature is enabled by setting the SRC_IGNORE bit in the Transfer Information field of a Control Block: "Do not perform source reads. In addition, destination writes will zero all the write strobes. This is used for fast cache fill operations." https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf The feature is only available on 8 of the 16 channels. The others are so-called "lite" channels with a limited feature set and performance. Enable the feature if a cyclic transaction copies from the zero page. This reduces traffic on the memory bus. A forthcoming use case is the BCM2835 SPI driver, which will cyclically copy from the zero page to the TX FIFO. The idea to use SRC_IGNORE was taken from an ancient GitHub conversation between Martin and Noralf: https://github.com/msperl/spi-bcm2835/issues/13#issuecomment-98180451Tested-by:
Vinod Koul <vkoul@kernel.org> Acked-by:
-
Lukas Wunner authored
The BCM2835 SPI driver needs to set up the clock polarity in its ->prepare_message() hook before spi_transfer_one_message() asserts chip select to avoid a gratuitous clock signal edge (cf. commit acace73d ("spi: bcm2835: set up spi-mode before asserting cs-gpio")). Precalculate the CS register value (which selects the clock polarity) once in ->setup() and use that cached value in ->prepare_message() and ->transfer_one(). This avoids one MMIO read per message and one per transfer, yielding a small latency improvement. Additionally, a forthcoming commit will use the precalculated value to derive the register value for clearing the RX FIFO, which will eliminate the need for an RX dummy buffer when performing TX-only DMA transfers. Tested-by:
-
Lukas Wunner authored
Document the BCM2835 DMA driver's device data structure so that upcoming commits may add further members with proper kerneldoc. Tested-by:
-
Lukas Wunner authored
__spi_alloc_controller() uses a single allocation to accommodate struct spi_controller and the driver-private data, but places the latter behind the former. This order does not guarantee cacheline alignment of the driver-private data. (It does guarantee cacheline alignment of struct spi_controller but the structure doesn't make any use of that property.) Round up struct spi_controller to cacheline size. A forthcoming commit leverages this to grant DMA access to driver-private data of the BCM2835 SPI master. An alternative, less economical approach would be to use two allocations. A third approach consists of reversing the order to conserve memory. But Mark Brown is concerned that it may result in a performance penalty on architectures that don't like unaligned accesses. Signed-off-by:
-
Lukas Wunner authored
The DMA engine API requires DMA drivers to explicitly allow that descriptors are prepared once and reused multiple times. Only a single driver makes use of this functionality so far (pxa_dma.c, to speed up pxa_camera.c). We're about to add another use case for reusable descriptors in the BCM2835 SPI driver, so allow that in the BCM2835 DMA driver. Tested-by:
-
Lukas Wunner authored
The BCM2835 DMA driver currently requests an interrupt from the controller regardless whether or not the client has passed in the DMA_PREP_INTERRUPT flag. This causes unnecessary overhead for cyclic transactions which do not need an interrupt after each period. We're about to add such a use case, namely cyclic clearing of the SPI controller's RX FIFO, so amend the DMA driver to request an interrupt only if DMA_PREP_INTERRUPT was passed in. Ignore the period_len for such transactions and set it to the buffer length to make the driver's calculations work. Tested-by:
-
Lukas Wunner authored
The BCM2835 SPI driver uses a flag to keep track of whether a DMA transfer is in progress. The flag is used to avoid terminating DMA channels multiple times if a transfer finishes orderly while simultaneously the SPI core invokes the ->handle_err() callback because the transfer took too long. However terminating DMA channels multiple times is perfectly fine, so the flag is unnecessary for this particular purpose. The flag is also used to avoid invoking bcm2835_spi_undo_prologue() multiple times under this race condition. However multiple *concurrent* invocations can no longer happen since commit 2527704d ("spi: bcm2835: Synchronize with callback on DMA termination") because the ->handle_err() callback now uses the _sync() variant when terminating DMA channels. The only raison d'être of the flag is therefore that bcm2835_spi_undo_prologue() cannot cope with multiple *sequential* invocations. Achieve that by setting tx_prologue to 0 at the end of the function. Subsequent invocations thus become no-ops. With that, the dma_pending flag becomes unnecessary, so drop it. Tested-by:
-
- 09 Sep, 2019 1 commit
-
-
Markus Elfring authored
Simplify this function implementation by using a known function. Generated by: scripts/coccinelle/api/ptr_ret.cocci Signed-off-by:
Markus Elfring <elfring@users.sourceforge.net> Reviewed-by:
Geert Uytterhoeven <geert+renesas@glider.be> Link: https://lore.kernel.org/r/b2dd074a-1693-3aea-42b4-da1f5ec155c4@web.deSigned-off-by:
-
- 05 Sep, 2019 2 commits
-
-
Vladimir Oltean authored
This helps a bit with line fitting now (the list_first_entry call) as well as during the next patch which needs to iterate through all transfers of ctlr->cur_msg so it timestamps them. Signed-off-by:
-
YueHaibing authored
drivers/spi/spi-npcm-fiu.c: In function npcm_fiu_read: drivers/spi/spi-npcm-fiu.c:472:9: warning: variable retlen set but not used [-Wunused-but-set-variable] It is never used, so remove it. Signed-off-by:
YueHaibing <yuehaibing@huawei.com> Link: https://lore.kernel.org/r/20190905072436.23932-1-yuehaibing@huawei.comSigned-off-by:
-
- 04 Sep, 2019 14 commits
-
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
Hulk Robot <hulkci@huawei.com> Signed-off-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
YueHaibing authored
Use devm_platform_ioremap_resource() to simplify the code a bit. This is detected by coccinelle. Reported-by:
-
