- 06 Feb, 2019 7 commits
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Tudor Ambarus authored
Return -ENOTSUPP when atmel_qspi_find_mode() fails. Propagate the error in atmel_qspi_exec_op(). Signed-off-by:
Tudor Ambarus <tudor.ambarus@microchip.com> Reviewed-by:
Boris Brezillon <bbrezillon@kernel.org> Signed-off-by:
Mark Brown <broonie@kernel.org>
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Tudor Ambarus authored
The cast is done implicitly. Signed-off-by:
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Tudor Ambarus authored
Let general names to core drivers. Signed-off-by:
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Tudor Ambarus authored
The wrappers hid that the accesses are relaxed. Drop them. Suggested-by:
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Tudor Ambarus authored
Cosmetic change, no functional change. Signed-off-by:
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Tudor Ambarus authored
Set the controller by default in Serial Memory Mode (SMM) at probe. Cache Mode Register (MR) value to avoid write access when setting the controller in serial memory mode at exec_op(). Signed-off-by:
Boris Brezillon <boris.brezillon@collabora.com> Signed-off-by:
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Lukasz Majewski authored
The NXP's Vybryd vf610 can work as a SPI slave device (the CS and clock signals are provided by master). It is possible to specify a single device to work in that mode. As we do use DMA for transferring data, the RX channel must be prepared for incoming data. Moreover, in slave mode we just set a subset of control fields in configuration registers (CTAR0, PUSHR). For testing the spidev_test program has been used. Test script for this patch can be found here: https://github.com/lmajewski/tests-spi/blob/master/tests/spi/spi_tests.shSigned-off-by:
Lukasz Majewski <lukma@denx.de> Signed-off-by:
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- 30 Jan, 2019 2 commits
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Jonas Bonn authored
If the SPI slave requires an inter-word delay, configure the DLYBCT register accordingly. Tested on a SAMA5D2 board (derived from SAMA5D2-Xplained reference board). Signed-off-by:
Jonas Bonn <jonas@norrbonn.se> Acked-by:
Nicolas Ferre <nicolas.ferre@microchip.com> CC: Nicolas Ferre <nicolas.ferre@microchip.com> CC: Mark Brown <broonie@kernel.org> CC: Alexandre Belloni <alexandre.belloni@bootlin.com> CC: Ludovic Desroches <ludovic.desroches@microchip.com> CC: linux-spi@vger.kernel.org CC: linux-arm-kernel@lists.infradead.org Signed-off-by:
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Jonas Bonn authored
Some devices are slow and cannot keep up with the SPI bus and therefore require a short delay between words of the SPI transfer. The example of this that I'm looking at is a SAMA5D2 with a minimum SPI clock of 400kHz talking to an AVR-based SPI slave. The AVR cannot put bytes on the bus fast enough to keep up with the SoC's SPI controller even at the lowest bus speed. This patch introduces the ability to specify a required inter-word delay for SPI devices. It is up to the controller driver to configure itself accordingly in order to introduce the requested delay. Note that, for spi_transfer, there is already a field word_delay that provides similar functionality. This field, however, is specified in clock cycles (and worse, SPI controller cycles, not SCK cycles); that makes this value dependent on the master clock instead of the device clock for which the delay is intended to provide some relief. This patch leaves this old word_delay in place and provides a time-based word_delay_us alongside it; the new field fits in the struct padding so struct size is constant. There is only one in-kernel user of the word_delay field and presumably that driver could be reworked to use the time-based value instead. The time-based delay is limited to 8 bits as these delays are intended to be short. The SAMA5D2 that I've tested this on limits delays to a maximum of ~100us, which is already many word-transfer periods even at the minimum transfer speed supported by the controller. Signed-off-by:
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- 29 Jan, 2019 3 commits
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Uwe Kleine-König authored
Driver specific implementations for .transfer_one_message need to call the tracing stuff themself. This is necessary to make spi tracing actually useful. Signed-off-by:
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by:
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Yogesh Narayan Gaur authored
Typo fix in Author Boris Brezillon last name and update with new email address. Fixes: 84d04318 ("spi: Add a driver for the Freescale/NXP QuadSPI controller") Signed-off-by:
Yogesh Narayan Gaur <yogeshnarayan.gaur@nxp.com> Signed-off-by:
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Yogesh Narayan Gaur authored
Add MODULE_LICENSE info to fix below warning: WARNING: modpost: missing MODULE_LICENSE() in drivers/spi/spi-nxp-fspi.o Typo fix in Boris Brezillon last name. Fixes: a5356aef ("spi: spi-mem: Add driver for NXP FlexSPI controller") Reported-by:
Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by:
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- 28 Jan, 2019 6 commits
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Jiwei Sun authored
When transfer timeout, give -EAGAIN to the message's status, and it can make the spi device driver choose repeated transimation or not. And if transfer timeout, output some useful information for tracing the issue. Signed-off-by:
Jiwei Sun <jiwei.sun@windriver.com> Reviewed-by:
Linus Walleij <linus.walleij@linaro.org> Signed-off-by:
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Fabio Estevam authored
The spi-imx driver supports both master and slave modes, so update the help text to make it more generic. Signed-off-by:
Fabio Estevam <festevam@gmail.com> Signed-off-by:
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Yogesh Narayan Gaur authored
Add octal mode flags for octal I/O data transfer support. NXP FlexSPI controller supports 8 lines Rx/Tx data transfer. Signed-off-by:
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Yogesh Narayan Gaur authored
Add maintainers for the NXP FlexSPI driver Signed-off-by:
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Yogesh Narayan Gaur authored
Add binding file for NXP FlexSPI controller Signed-off-by:
Rob Herring <robh@kernel.org> Signed-off-by:
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Yogesh Narayan Gaur authored
- Add driver for NXP FlexSPI host controller (0) What is the FlexSPI controller? FlexSPI is a flexsible SPI host controller which supports two SPI channels and up to 4 external devices. Each channel supports Single/Dual/Quad/Octal mode data transfer (1/2/4/8 bidirectional data lines) i.e. FlexSPI acts as an interface to external devices, maximum 4, each with up to 8 bidirectional data lines. It uses new SPI memory interface of the SPI framework to issue flash memory operations to up to four connected flash devices (2 buses with 2 CS each). (1) Tested this driver with the mtd_debug and JFFS2 filesystem utility on NXP LX2160ARDB and LX2160AQDS targets. LX2160ARDB is having two NOR slave device connected on single bus A i.e. A0 and A1 (CS0 and CS1). LX2160AQDS is having two NOR slave device connected on separate buses one flash on A0 and second on B1 i.e. (CS0 and CS3). Verified this driver on following SPI NOR flashes: Micron, mt35xu512ab, [Read - 1 bit mode] Cypress, s25fl512s, [Read - 1/2/4 bit mode] Signed-off-by:Frieder Schrempf <frieder.schrempf@kontron.de> Reviewed-by:
Ashish Kumar <Ashish.Kumar@nxp.com> Signed-off-by:
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- 24 Jan, 2019 4 commits
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Linus Walleij authored
The SPI chip selects were not properly inspected due to a logic inversion. This made SPI GPIOs not work. Cc: Jan Kotas <jank@cadence.com> Reported-by:
Jan Kotas <jank@cadence.com> Tested-by:
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Linus Walleij authored
The Cadence controller also supports platforms specifying native chipselects. When I enforce the use of high CS for drivers opting in for using GPIO descriptors, I inadvertedly switched the driver to also use active high chip select for native chip selects. Fix this by inverting the logic in the callback for the native chip select. Rename the parameter from "is_high" (which is interpreted as being high when 0, which is confusing, I will not make any drug-related jokes here) to "enabled" which is more intuitive, especially now that it is true when CS is supposed to be enabled. Cc: Wei Yongjun <weiyongjun1@huawei.com> Fixes: cfeefa79 ("spi: cadence: Convert to use CS GPIO descriptors") Signed-off-by:
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Linus Walleij authored
The DW controller also supports platforms specifying native chipselects. When I enforce the use of high CS for drivers opting in for using GPIO descriptors, I inadvertedly switched the driver to also use active high chip select for native chip selects. As it turns out, the DW hardware driving chip selects also thinks it is weird with active low chip selects so all we need to do is remove an inversion in the driver. Cc: Jan Kotas <jank@cadence.com> Reported-by:
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Linus Walleij authored
All controllers using GPIO descriptors can by definition support high CS connections, so just enforce this when registering an SPI controller. This fixes a regression where controllers were missing SPI_CS_HIGH, the drivers would fail like this: spi spi0.0: setup: unsupported mode bits 4 cdns-spi fd0b0000.spi: can't setup spi0.0, status -22 This is because as using descriptors moves the CS inversion logic over to gpiolib, all such controllers are registered with CS active high. Cc: Jan Kotas <jank@cadence.com> Reported-by:
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- 23 Jan, 2019 3 commits
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Mark Brown authored
Commit 412e6037 ("spi: core: avoid waking pump thread from spi_sync instead run teardown delayed") introduced regressions on some boards, apparently connected to spi_mem not triggering shutdown properly any more. Since we've thus far been unable to figure out exactly where the breakage is revert the optimisation for now. Reported-by:
Jon Hunter <jonathanh@nvidia.com> Signed-off-by:
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Lubomir Rintel authored
It's also a slave controller driver now, calling it "master" is slightly misleading. Signed-off-by:
Lubomir Rintel <lkundrak@v3.sk> Acked-by:
Robert Jarzmik <robert.jarzmik@free.fr> Signed-off-by:
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YueHaibing authored
Fix a static code checker warning: drivers/spi/spi-bcm2835aux.c:460 bcm2835aux_spi_probe() warn: passing zero to 'PTR_ERR' In case of error, the function devm_clk_get() returns ERR_PTR() and not returns NULL. Signed-off-by:
YueHaibing <yuehaibing@huawei.com> Signed-off-by:
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- 21 Jan, 2019 1 commit
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Boris Brezillon authored
Since direct mapping descriptors usually the same lifetime as the SPI MEM device adding devm_ variants of the spi_mem_dirmap_{create,destroy}() should greatly simplify error/remove path of spi-mem drivers making use of the direct mapping API. Signed-off-by:
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- 18 Jan, 2019 3 commits
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Hoan Nguyen An authored
Currently, this driver only supports feature for DMA 32-bits. In this case, only if the data length is divisible by 4 to use DMA, otherwise PIO will be used. This patch will suggest use the DMA 32-bits with 4bytes of words, then the remaining data will be transmitted by PIO mode. Signed-off-by:
Hoan Nguyen An <na-hoan@jinso.co.jp> Reviewed-by:
Geert Uytterhoeven <geert+renesas@glider.be> Tested-by:
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Hoan Nguyen An authored
sh_msiof_spi_info *info struct pointer was initialized in the probe() function no need to get back and keep consistency. Signed-off-by:
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Geert Uytterhoeven authored
There is no need to print an error message when memory allocations or related operations fail, as the core will take care of that. Signed-off-by:
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- 17 Jan, 2019 4 commits
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Alban Bedel authored
The custom setup/cleanup routines included in the ath79 driver only take care of setting the initial CS state. However that is already handled by the bitbang code, so this code can be removed. Signed-off-by:
Alban Bedel <albeu@free.fr> Signed-off-by:
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Alban Bedel authored
To allow building this driver in compile test we need to remove all dependency on headers from arch/mips/include. To allow this we explicitly define all the registers locally instead of using ar71xx_regs.h and we move the platform data struct definition to include/linux/platform_data/spi-ath79.h. Signed-off-by:
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Alban Bedel authored
First of all this callback was slightly misused to setup the clock polarity at the beginning of a transfer. Beside being at the wrong place, it is also useless as only SPI mode 1 is supported. Instead just make sure the base value used for IOC is suitable to start a transfer by clearing the clock and data bits during the controller setup. This also remove the last direct usage of the GPIO API, so we can remove the direct dependency on GPIOLIB. Signed-off-by:
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Alban Bedel authored
spi_setup() already call spi_set_cs() right after calling the controller setup method, so there is no need for the bitbang driver to do that. Because of this the chipselect() callback was confusingly still called when CS is GPIO based. Signed-off-by:
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- 14 Jan, 2019 3 commits
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Charles Keepax authored
Currently the driver calls pm_runtime_put_autosuspend but without ever having done a pm_runtime_get, this causes the reference count in the pm runtime core to become -1. The bad reference count causes the core to sometimes suspend whilst an active SPI transfer is in progress. arizona spi0.1: SPI transfer timed out spi_master spi0: failed to transfer one message from queue The correct proceedure is to do all the initialisation that requires the hardware to be powered up before enabling the PM runtime, then enable the PM runtime having called pm_runtime_set_active to inform it that the hardware is currently powered up. The core will then power it down at it's leisure and no explicit pm_runtime_put is required. Fixes: d36ccd9f ("spi: cadence: Runtime pm adaptation") Signed-off-by:
Charles Keepax <ckeepax@opensource.cirrus.com> Signed-off-by:
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Stephen Boyd authored
We don't need this forward declaration. Move the function to where it needed so we can drop it and shave some lines of code. CC: Girish Mahadevan <girishm@codeaurora.org> CC: Dilip Kota <dkota@codeaurora.org> CC: Alok Chauhan <alokc@codeaurora.org> Cc: Douglas Anderson <dianders@chromium.org> Signed-off-by:
Stephen Boyd <swboyd@chromium.org> Signed-off-by:
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Stephen Boyd authored
We only use this completion when we're doing something that isn't a message transfer. For example, changing CS or aborting/canceling a command. All of those situations properly reinitialize the completion before sending the GENI the special command to change CS or cancel, etc. Given that, let's remove the initialization here. Cc: Girish Mahadevan <girishm@codeaurora.org> Cc: Dilip Kota <dkota@codeaurora.org> Cc: Alok Chauhan <alokc@codeaurora.org> Cc: Douglas Anderson <dianders@chromium.org> Signed-off-by:
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- 10 Jan, 2019 2 commits
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Linus Walleij authored
The previous commit left a variable unused, my bad. Clean it up. Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: David Lechner <david@lechnology.com> Reported-by:
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Anders Roxell authored
When CONFIG_SPI_DESIGNWARE are enabled we see the unused variable warning in dw_spi_setup. ../drivers/spi/spi-dw.c: In function ‘dw_spi_setup’: ../drivers/spi/spi-dw.c:400:6: warning: unused variable ‘ret’ [-Wunused-variable] int ret; ^~~ Remove the unused varable. Fixes: 9400c41e ("spi: dw: Convert to use CS GPIO descriptors") Reported-by:Anders Roxell <anders.roxell@linaro.org> Signed-off-by:
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- 09 Jan, 2019 2 commits
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Martin Sperl authored
When spi_sync is running alone with no other spi devices connected to the bus the worker thread is woken during spi_finalize_current_message to run the teardown code every time. This is totally unnecessary in the case that there is no message queued. On a multi-core system this results in one wakeup of the thread for each spi_message processed via spi_sync where in most cases the teardown does not happen as the hw is already in use. This patch now delays the teardown by 1 second by using a separate kthread_delayed_work for the teardown. This avoids waking the kthread too often. For spi_sync transfers in a tight loop (say 40k messages/s) this avoids the penalty of waking the worker thread 40k times/s. On a rasperry pi 3 with 4 cores the results in 32% of a single core only to find out that there is nothing in the queue and it can go back to sleep. With this patch applied the spi-worker is woken exactly once: after the load finishes and the spi bus is idle for 1 second. I believe I have also seen situations where during a spi_sync loop the worker thread (triggered by the last message finished) is slightly faster and _wins_ the race to process the message, so we are actually running the kthread and letting it do some work... This is also no longer observed with this patch applied as. Tested with a new CAN controller driver for the mcp2517fd which uses spi_sync for interrupt handling and spi_async for scheduling of can frames for transmission (in a different thread) Some statistics when receiving 100000 CAN frames with the mcp25xxfd driver on a Raspberry pi 3: without the patch: ------------------ root@raspcm3:~# for x in $(pgrep spi0) $(pgrep irq/94-mcp25xxf) ; do awk '{printf "%-20s %6i\n", $2,$15}' /proc/$x/stat; done (spi0) 5 (irq/94-mcp25xxf) 0 root@raspcm3:~# vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 1 0 0 821960 13592 50848 0 0 80 2 1986 105 1 2 97 0 0 0 0 0 821968 13592 50876 0 0 0 0 8046 30 0 0 100 0 0 0 0 0 821936 13592 50876 0 0 0 0 8032 24 0 0 100 0 0 0 0 0 821936 13592 50876 0 0 0 0 8035 30 0 0 100 0 0 0 0 0 821936 13592 50876 0 0 0 0 8033 22 0 0 100 0 0 2 0 0 821936 13592 50876 0 0 0 0 11598 7129 0 3 97 0 0 1 0 0 821872 13592 50876 0 0 0 0 37741 59003 0 31 69 0 0 2 0 0 821840 13592 50876 0 0 0 0 37762 59078 0 29 71 0 0 2 0 0 821776 13592 50876 0 0 0 0 37593 58792 0 28 72 0 0 1 0 0 821744 13592 50876 0 0 0 0 37642 58881 0 30 70 0 0 2 0 0 821680 13592 50876 0 0 0 0 37490 58602 0 27 73 0 0 1 0 0 821648 13592 50876 0 0 0 0 37412 58418 0 29 71 0 0 1 0 0 821584 13592 50876 0 0 0 0 37337 58288 0 27 73 0 0 1 0 0 821552 13592 50876 0 0 0 0 37584 58774 0 27 73 0 0 0 0 0 821520 13592 50876 0 0 0 0 18363 20566 0 9 91 0 0 0 0 0 821520 13592 50876 0 0 0 0 8037 32 0 0 100 0 0 0 0 0 821520 13592 50876 0 0 0 0 8031 23 0 0 100 0 0 0 0 0 821520 13592 50876 0 0 0 0 8034 26 0 0 100 0 0 0 0 0 821520 13592 50876 0 0 0 0 8033 24 0 0 100 0 0 ^C root@raspcm3:~# for x in $(pgrep spi0) $(pgrep irq/94-mcp25xxf) ; do awk '{printf "%-20s %6i\n", $2,$15}' /proc/$x/stat; done (spi0) 228 (irq/94-mcp25xxf) 794 root@raspcm3:~# cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 17: 34 0 0 0 ARMCTRL-level 1 Edge 3f00b880.mailbox 27: 1 0 0 0 ARMCTRL-level 35 Edge timer 33: 1416870 0 0 0 ARMCTRL-level 41 Edge 3f980000.usb, dwc2_hsotg:usb1 34: 1 0 0 0 ARMCTRL-level 42 Edge vc4 35: 0 0 0 0 ARMCTRL-level 43 Edge 3f004000.txp 40: 1753 0 0 0 ARMCTRL-level 48 Edge DMA IRQ 42: 11 0 0 0 ARMCTRL-level 50 Edge DMA IRQ 44: 11 0 0 0 ARMCTRL-level 52 Edge DMA IRQ 45: 0 0 0 0 ARMCTRL-level 53 Edge DMA IRQ 66: 0 0 0 0 ARMCTRL-level 74 Edge vc4 crtc 69: 0 0 0 0 ARMCTRL-level 77 Edge vc4 crtc 70: 0 0 0 0 ARMCTRL-level 78 Edge vc4 crtc 77: 20 0 0 0 ARMCTRL-level 85 Edge 3f205000.i2c, 3f804000.i2c, 3f805000.i2c 78: 6346 0 0 0 ARMCTRL-level 86 Edge 3f204000.spi 80: 205 0 0 0 ARMCTRL-level 88 Edge mmc0 81: 493 0 0 0 ARMCTRL-level 89 Edge uart-pl011 89: 0 0 0 0 bcm2836-timer 0 Edge arch_timer 90: 4291 3821 2180 1649 bcm2836-timer 1 Edge arch_timer 94: 14289 0 0 0 pinctrl-bcm2835 16 Level mcp25xxfd IPI0: 0 0 0 0 CPU wakeup interrupts IPI1: 0 0 0 0 Timer broadcast interrupts IPI2: 3645 242371 7919 1328 Rescheduling interrupts IPI3: 112 543 273 194 Function call interrupts IPI4: 0 0 0 0 CPU stop interrupts IPI5: 1 0 0 0 IRQ work interrupts IPI6: 0 0 0 0 completion interrupts Err: 0 top shows 93% for the mcp25xxfd interrupt handler, 31% for spi0. with the patch: --------------- root@raspcm3:~# for x in $(pgrep spi0) $(pgrep irq/94-mcp25xxf) ; do awk '{printf "%-20s %6i\n", $2,$15}' /proc/$x/stat; done (spi0) 0 (irq/94-mcp25xxf) 0 root@raspcm3:~# vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- 0 0 0 804768 13584 62628 0 0 0 0 8038 24 0 0 100 0 0 0 0 0 804768 13584 62628 0 0 0 0 8042 25 0 0 100 0 0 1 0 0 804704 13584 62628 0 0 0 0 9603 2967 0 20 80 0 0 1 0 0 804672 13584 62628 0 0 0 0 9828 3380 0 24 76 0 0 1 0 0 804608 13584 62628 0 0 0 0 9823 3375 0 23 77 0 0 1 0 0 804608 13584 62628 0 0 0 12 9829 3394 0 23 77 0 0 1 0 0 804544 13584 62628 0 0 0 0 9816 3362 0 22 78 0 0 1 0 0 804512 13584 62628 0 0 0 0 9817 3367 0 23 77 0 0 1 0 0 804448 13584 62628 0 0 0 0 9822 3370 0 22 78 0 0 1 0 0 804416 13584 62628 0 0 0 0 9815 3367 0 23 77 0 0 0 0 0 804352 13584 62628 0 0 0 84 9222 2250 0 14 86 0 0 0 0 0 804352 13592 62620 0 0 0 24 8131 209 0 0 93 7 0 0 0 0 804320 13592 62628 0 0 0 0 8041 27 0 0 100 0 0 0 0 0 804352 13592 62628 0 0 0 0 8040 26 0 0 100 0 0 root@raspcm3:~# for x in $(pgrep spi0) $(pgrep irq/94-mcp25xxf) ; do awk '{printf "%-20s %6i\n", $2,$15}' /proc/$x/stat; done (spi0) 0 (irq/94-mcp25xxf) 767 root@raspcm3:~# cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 17: 29 0 0 0 ARMCTRL-level 1 Edge 3f00b880.mailbox 27: 1 0 0 0 ARMCTRL-level 35 Edge timer 33: 1024412 0 0 0 ARMCTRL-level 41 Edge 3f980000.usb, dwc2_hsotg:usb1 34: 1 0 0 0 ARMCTRL-level 42 Edge vc4 35: 0 0 0 0 ARMCTRL-level 43 Edge 3f004000.txp 40: 1773 0 0 0 ARMCTRL-level 48 Edge DMA IRQ 42: 11 0 0 0 ARMCTRL-level 50 Edge DMA IRQ 44: 11 0 0 0 ARMCTRL-level 52 Edge DMA IRQ 45: 0 0 0 0 ARMCTRL-level 53 Edge DMA IRQ 66: 0 0 0 0 ARMCTRL-level 74 Edge vc4 crtc 69: 0 0 0 0 ARMCTRL-level 77 Edge vc4 crtc 70: 0 0 0 0 ARMCTRL-level 78 Edge vc4 crtc 77: 20 0 0 0 ARMCTRL-level 85 Edge 3f205000.i2c, 3f804000.i2c, 3f805000.i2c 78: 6417 0 0 0 ARMCTRL-level 86 Edge 3f204000.spi 80: 237 0 0 0 ARMCTRL-level 88 Edge mmc0 81: 489 0 0 0 ARMCTRL-level 89 Edge uart-pl011 89: 0 0 0 0 bcm2836-timer 0 Edge arch_timer 90: 4048 3704 2383 1892 bcm2836-timer 1 Edge arch_timer 94: 14287 0 0 0 pinctrl-bcm2835 16 Level mcp25xxfd IPI0: 0 0 0 0 CPU wakeup interrupts IPI1: 0 0 0 0 Timer broadcast interrupts IPI2: 2361 2948 7890 1616 Rescheduling interrupts IPI3: 65 617 301 166 Function call interrupts IPI4: 0 0 0 0 CPU stop interrupts IPI5: 1 0 0 0 IRQ work interrupts IPI6: 0 0 0 0 completion interrupts Err: 0 top shows 91% for the mcp25xxfd interrupt handler, 0% for spi0 So we see that spi0 is no longer getting scheduled wasting CPU cycles There are a lot less context switches and corresponding Rescheduling interrupts All of these show that this improves efficiency of the system and reduces CPU utilization. Signed-off-by:Martin Sperl <kernel@martin.sperl.org> Signed-off-by:
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Linus Walleij authored
This converts the DesignWare (dw) SPI master driver to use GPIO descriptors for chip select handling. This driver has a duplicate DT parser in addition to the one in the core, sets up the line as non-asserted and relies on the core to drive the GPIOs. It is a pretty straight-forward conversion. Cc: Talel Shenhar <talel@amazon.com> Cc: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Linuxarm <linuxarm@huawei.com> Tested-by:
Jay Fang <f.fangjian@huawei.com> Reviewed-by:
Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by:
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