- 25 Jun, 2020 1 commit
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Jarkko Nikula authored
Add Intel Tiger Lake PCH-H PCI IDs. Signed-off-by:
Jarkko Nikula <jarkko.nikula@linux.intel.com> Link: https://lore.kernel.org/r/20200625140041.745804-1-jarkko.nikula@linux.intel.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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- 22 Jun, 2020 4 commits
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Krzysztof Kozlowski authored
The interrupt handler calls completion and is IRQ requested before the completion is initialized. Logically it should be the other way. Signed-off-by:
Krzysztof Kozlowski <krzk@kernel.org> Link: https://lore.kernel.org/r/20200622110543.5035-4-krzk@kernel.orgSigned-off-by:
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Krzysztof Kozlowski authored
If shared interrupt comes late, during probe error path or device remove (could be triggered with CONFIG_DEBUG_SHIRQ), the interrupt handler dspi_interrupt() will access registers with the clock being disabled. This leads to external abort on non-linefetch on Toradex Colibri VF50 module (with Vybrid VF5xx): $ echo 4002d000.spi > /sys/devices/platform/soc/40000000.bus/4002d000.spi/driver/unbind Unhandled fault: external abort on non-linefetch (0x1008) at 0x8887f02c Internal error: : 1008 [#1] ARM Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree) Backtrace: (regmap_mmio_read32le) (regmap_mmio_read) (_regmap_bus_reg_read) (_regmap_read) (regmap_read) (dspi_interrupt) (free_irq) (devm_irq_release) (release_nodes) (devres_release_all) (device_release_driver_internal) The resource-managed framework should not be used for shared interrupt handling, because the interrupt handler might be called after releasing other resources and disabling clocks. Similar bug could happen during suspend - the shared interrupt handler could be invoked after suspending the device. Each device sharing this interrupt line should disable the IRQ during suspend so handler will be invoked only in following cases: 1. None suspended, 2. All devices resumed. Fixes: 349ad66c ("spi:Add Freescale DSPI driver for Vybrid VF610 platform") Signed-off-by:Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by:
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Krzysztof Kozlowski authored
During shutdown, the driver should unregister the SPI controller and stop the hardware. Otherwise the dspi_transfer_one_message() could wait on completion infinitely. Additionally, calling spi_unregister_controller() first in device shutdown reverse-matches the probe function, where SPI controller is registered at the end. Fixes: dc234825 ("spi: spi-fsl-dspi: Adding shutdown hook") Reported-by:
Vladimir Oltean <olteanv@gmail.com> Signed-off-by:
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Krzysztof Kozlowski authored
During device removal, the driver should unregister the SPI controller and stop the hardware. Otherwise the dspi_transfer_one_message() could wait on completion infinitely. Additionally, calling spi_unregister_controller() first in device removal reverse-matches the probe function, where SPI controller is registered at the end. Fixes: 05209f45 ("spi: fsl-dspi: add missing clk_disable_unprepare() in dspi_remove()") Reported-by:
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- 18 Jun, 2020 2 commits
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Zhenzhong Duan authored
If an spi device is unbounded from the driver before the release process, there will be an NULL pointer reference when it's referenced in spi_slave_abort(). Fix it by checking it's already freed before reference. Signed-off-by:
Zhenzhong Duan <zhenzhong.duan@gmail.com> Link: https://lore.kernel.org/r/20200618032125.4650-2-zhenzhong.duan@gmail.comSigned-off-by:
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Zhenzhong Duan authored
Imagine below scene, spidev is referenced after it's freed. spidev_release() spidev_remove() ... spin_lock_irq(&spidev->spi_lock); spidev->spi = NULL; spin_unlock_irq(&spidev->spi_lock); mutex_lock(&device_list_lock); dofree = (spidev->spi == NULL); if (dofree) kfree(spidev); mutex_unlock(&device_list_lock); mutex_lock(&device_list_lock); list_del(&spidev->device_entry); device_destroy(spidev_class, spidev->devt); clear_bit(MINOR(spidev->devt), minors); if (spidev->users == 0) kfree(spidev); mutex_unlock(&device_list_lock); Fix it by resetting spidev->spi in device_list_lock's protection. Signed-off-by:
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- 17 Jun, 2020 1 commit
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Patrice Chotard authored
In case of -EPROBE_DEFER, stm32_qspi_release() was called in any case which unregistered driver from pm_runtime framework even if it has not been registered yet to it. This leads to: stm32-qspi 58003000.spi: can't setup spi0.0, status -13 spi_master spi0: spi_device register error /soc/spi@58003000/mx66l51235l@0 spi_master spi0: Failed to create SPI device for /soc/spi@58003000/mx66l51235l@0 stm32-qspi 58003000.spi: can't setup spi0.1, status -13 spi_master spi0: spi_device register error /soc/spi@58003000/mx66l51235l@1 spi_master spi0: Failed to create SPI device for /soc/spi@58003000/mx66l51235l@1 On v5.7 kernel,this issue was not "visible", qspi driver was probed successfully. Fixes: 9d282c17 ("spi: stm32-qspi: Add pm_runtime support") Signed-off-by:
Patrice Chotard <patrice.chotard@st.com> Link: https://lore.kernel.org/r/20200616113035.4514-1-patrice.chotard@st.comSigned-off-by:
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- 15 Jun, 2020 1 commit
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Geert Uytterhoeven authored
The UAPI <linux/spi/spidev.h> uses TABs for alignment. Convert the recently introduced spaces to TABs to restore consistency. Fixes: 7bb64402 ("spi: tools: Add macro definitions to fix build errors") Signed-off-by:
Geert Uytterhoeven <geert+renesas@glider.be> Link: https://lore.kernel.org/r/20200613073755.15906-1-geert+renesas@glider.beSigned-off-by:
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- 11 Jun, 2020 3 commits
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Krzysztof Kozlowski authored
Driver allocates DMA memory with dma_alloc_coherent() but frees it with dma_unmap_single(). This causes DMA warning during system shutdown (with DMA debugging) on Toradex Colibri VF50 module: WARNING: CPU: 0 PID: 1 at ../kernel/dma/debug.c:1036 check_unmap+0x3fc/0xb04 DMA-API: fsl-edma 40098000.dma-controller: device driver frees DMA memory with wrong function [device address=0x0000000087040000] [size=8 bytes] [mapped as coherent] [unmapped as single] Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree) (unwind_backtrace) from [<8010bb34>] (show_stack+0x10/0x14) (show_stack) from [<8011ced8>] (__warn+0xf0/0x108) (__warn) from [<8011cf64>] (warn_slowpath_fmt+0x74/0xb8) (warn_slowpath_fmt) from [<8017d170>] (check_unmap+0x3fc/0xb04) (check_unmap) from [<8017d900>] (debug_dma_unmap_page+0x88/0x90) (debug_dma_unmap_page) from [<80601d68>] (dspi_release_dma+0x88/0x110) (dspi_release_dma) from [<80601e4c>] (dspi_shutdown+0x5c/0x80) (dspi_shutdown) from [<805845f8>] (device_shutdown+0x17c/0x220) (device_shutdown) from [<80143ef8>] (kernel_restart+0xc/0x50) (kernel_restart) from [<801441cc>] (__do_sys_reboot+0x18c/0x210) (__do_sys_reboot) from [<80100060>] (ret_fast_syscall+0x0/0x28) DMA-API: Mapped at: dma_alloc_attrs+0xa4/0x130 dspi_probe+0x568/0x7b4 platform_drv_probe+0x6c/0xa4 really_probe+0x208/0x348 driver_probe_device+0x5c/0xb4 Fixes: 90ba3703 ("spi: spi-fsl-dspi: Add DMA support for Vybrid") Signed-off-by: -
Qing Zhang authored
Add SPI_TX_OCTAL and SPI_RX_OCTAL to fix the following build errors: CC spidev_test.o spidev_test.c: In function ‘transfer’: spidev_test.c:131:13: error: ‘SPI_TX_OCTAL’ undeclared (first use in this function) if (mode & SPI_TX_OCTAL) ^ spidev_test.c:131:13: note: each undeclared identifier is reported only once for each function it appears in spidev_test.c:137:13: error: ‘SPI_RX_OCTAL’ undeclared (first use in this function) if (mode & SPI_RX_OCTAL) ^ spidev_test.c: In function ‘parse_opts’: spidev_test.c:290:12: error: ‘SPI_TX_OCTAL’ undeclared (first use in this function) mode |= SPI_TX_OCTAL; ^ spidev_test.c:308:12: error: ‘SPI_RX_OCTAL’ undeclared (first use in this function) mode |= SPI_RX_OCTAL; ^ LD spidev_test-in.o ld: cannot find spidev_test.o: No such file or directory Additionally, maybe SPI_CS_WORD and SPI_3WIRE_HIZ will be used in the future, so add them too. Fixes: 896fa735 ("spi: spidev_test: Add support for Octal mode data transfers") Signed-off-by:Qing Zhang <zhangqing@loongson.cn> Reviewed-by:
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Qing Zhang authored
Fix the following sparse warning: ./spidev_test.c:50:9: warning: symbol 'default_tx' was not declared. Should it be static? ./spidev_test.c:59:9: warning: symbol 'default_rx' was not declared. Should it be static? ./spidev_test.c:60:6: warning: symbol 'input_tx' was not declared. Should it be static? Signed-off-by:
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- 10 Jun, 2020 1 commit
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Alexander Stein authored
spi@13000: clock-names: Additional items are not allowed ('pclk' was unexpected) spi@13000: clock-names: ['core', 'pclk'] is too long spi@13000: clocks: [[2, 23], [2, 258]] is too long spi@15000: clock-names: Additional items are not allowed ('pclk' was unexpected) spi@15000: clock-names: ['core', 'pclk'] is too long spi@15000: clocks: [[2, 29], [2, 261]] is too long Conditional schema properties don't overwrite others. Instead of restrictions have to be validated. So general clock amount is 1-2 and depending on the actual device type limit the mount to 1 or 2. Signed-off-by:Alexander Stein <alexander.stein@mailbox.org> Link: https://lore.kernel.org/r/20200609165527.55183-1-alexander.stein@mailbox.orgSigned-off-by:
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- 09 Jun, 2020 1 commit
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Geert Uytterhoeven authored
Currently, the RSPI driver always tries to use the maximum configured bit rate for communicating with a slave device, even if the transfer(s) in the current message specify a lower rate. Use the mininum rate specified in the message instead. Rename rspi_data.max_speed_hz accordingly. Signed-off-by:
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- 08 Jun, 2020 1 commit
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Geert Uytterhoeven authored
Consistently use %u to format unsigned numbers. For "bits" this doesn't matter that much, as it is "uint8_t". However, "speed" is "uint32_t", so in case people use "-s -1" to force the maximum, they would see: max speed: -1 Hz (4294967 KHz) While at it, use "k" (kilo) instead of "K" (kelvin) in "kHz". Signed-off-by:
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- 02 Jun, 2020 1 commit
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Lingling Xu authored
The watchdog counter consists of WDG_LOAD_LOW and WDG_LOAD_HIGH, which would be loaded to watchdog counter once writing WDG_LOAD_LOW. Fixes: ac177501 ("spi: sprd: Add the support of restarting the system") Signed-off-by:
Lingling Xu <ling_ling.xu@unisoc.com> Signed-off-by:
Chunyan Zhang <chunyan.zhang@unisoc.com> Link: https://lore.kernel.org/r/20200602082415.5848-1-zhang.lyra@gmail.comSigned-off-by:
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- 29 May, 2020 24 commits
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Angelo Dureghello authored
ColdFire is a big-endian cpu with a big-endian dspi hw module, so, it uses native access, but memcpy breaks the endianness. So, if i understand properly, by native copy we would mean be(cpu)->be(dspi) or le(cpu)->le(dspi) accesses, so my fix shouldn't break anything, but i couldn't test it on LS family, so every test is really appreciated. Fixes: 53fadb4d ("spi: spi-fsl-dspi: Simplify bytes_per_word gymnastics") Signed-off-by:
Angelo Dureghello <angelo.dureghello@timesys.com> Tested-by:
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Serge Semin authored
Modern device tree bindings are supposed to be created as YAML-files in accordance with dt-schema. This commit replaces two DW SPI legacy bare text bindings with YAML file. As before the bindings file states that the corresponding dts node is supposed to be compatible either with generic DW APB SSI controller or with Microsemi/Amazon/Renesas/Intel vendors-specific controllers, to have registers, interrupts and clocks properties. Though in case of Microsemi version of the controller there must be two registers resources specified. Properties like clock-names, reg-io-width, cs-gpio, num-cs, DMA and slave device sub-nodes are optional. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by:
Rob Herring <robh@kernel.org> Cc: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru> Cc: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Feng Tang <feng.tang@intel.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-mips@vger.kernel.org Link: https://lore.kernel.org/r/20200529182544.9807-1-Sergey.Semin@baikalelectronics.ruSigned-off-by:
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Andy Shevchenko authored
It's better to understand what bits are set for DMA and for IRQ handling in mid_spi_dma_setup() if they are grouped accordingly. Thus, refactor mid_spi_dma_setup() to separate DMA and IRQ configuration. Signed-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200529183150.44149-2-andriy.shevchenko@linux.intel.comSigned-off-by:
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Andy Shevchenko authored
The 2afccbd2 ("spi: dw: Discard static DW DMA slave structures") did a clean up of global variables, which is fine, but messed up with the carefully provided information in the custom DMA slave structures. There reader can find an assignment of the DMA request lines in use. Partially revert the above mentioned commit to restore readability and maintainability of the code. Signed-off-by:
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Mark Brown authored
This reverts commit ecfbd3cf since Lukas Wunner noticed that we start operating on the hardware before we check to see if this is a spurious interrupt. Reported-by:
Lukas Wunner <lukas@wunner.de> Signed-off-by:
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Mark Brown authored
Merge series "spi: dw: Add generic DW DMA controller support" from Serge Semin <Sergey.Semin@baikalelectronics.ru>: Baikal-T1 SoC provides a DW DMA controller to perform low-speed peripherals Mem-to-Dev and Dev-to-Mem transaction. This is also applicable to the DW APB SSI devices embedded into the SoC. Currently the DMA-based transfers are supported by the DW APB SPI driver only as a middle layer code for Intel MID/Elkhart PCI devices. Seeing the same code can be used for normal platform DMAC device we introduced a set of patches to fix it within this series. First of all we need to add the Tx and Rx DMA channels support into the DW APB SSI binding. Then there are several fixes and cleanups provided as a initial preparation for the Generic DMA support integration: add Tx/Rx finish wait methods, clear DMAC register when done or stopped, Fix native CS being unset, enable interrupts in accordance with DMA xfer mode, discard static DW DMA slave structures, discard unused void priv pointer and dma_width member of the dw_spi structure, provide the DMA Tx/Rx burst length parametrisation and make sure it's optionally set in accordance with the DMA max-burst capability. In order to have the DW APB SSI MMIO driver working with DMA we need to initialize the paddr field with the physical base address of the DW APB SSI registers space. Then we unpin the Intel MID specific code from the generic DMA one and placed it into the spi-dw-pci.c driver, which is a better place for it anyway. After that the naming cleanups are performed since the code is going to be used for a generic DMAC device. Finally the Generic DMA initialization can be added to the generic version of the DW APB SSI IP. Last but not least we traditionally convert the legacy plain text-based dt-binding file with yaml-based one and as a cherry on a cake replace the manually written DebugFS registers read method with a ready-to-use for the same purpose regset32 DebugFS interface usage. This patchset is rebased and tested on the spi/for-next (5.7-rc5): base-commit: fe9fce6b2cf3 ("Merge remote-tracking branch 'spi/for-5.8' into spi-next") Link: https://lore.kernel.org/linux-spi/20200508132943.9826-1-Sergey.Semin@baikalelectronics.ru/ Changelog v2: - Rebase on top of the spi repository for-next branch. - Move bindings conversion patch to the tail of the series. - Move fixes to the head of the series. - Apply as many changes as possible to be applied the Generic DMA functionality support is added and the spi-dw-mid is moved to the spi-dw-dma driver. - Discard patch "spi: dw: Fix dma_slave_config used partly uninitialized" since the problem has already been fixed. - Add new patch "spi: dw: Discard unused void priv pointer". - Add new patch "spi: dw: Discard dma_width member of the dw_spi structure". n_bytes member of the DW SPI data can be used instead. - Build the DMA functionality into the DW APB SSI core if required instead of creating a separate kernel module. - Use conditional statement instead of the ternary operator in the ref clock getter. Link: https://lore.kernel.org/linux-spi/20200515104758.6934-1-Sergey.Semin@baikalelectronics.ru/ Changelog v3: - Use spi_delay_exec() method to wait for the DMA operation completion. - Explicitly initialize the dw_dma_slave members on stack. - Discard the dws->fifo_len utilization in the Tx FIFO DMA threshold setting from the patch where we just add the default burst length constants. - Use min() method to calculate the optimal burst values. - Add new patch which moves the spi-dw.c source file to spi-dw-core.c in order to preserve the DW APB SSI core driver name. - Add commas in the debugfs_reg32 structure initializer and after the last entry of the dw_spi_dbgfs_regs array. Link: https://lore.kernel.org/linux-spi/20200521012206.14472-1-Sergey.Semin@baikalelectronics.ru Changelog v4: - Get back ndelay() method to wait for an SPI transfer completion. spi_delay_exec() isn't suitable for the atomic context. Link: https://lore.kernel.org/linux-spi/20200522000806.7381-1-Sergey.Semin@baikalelectronics.ru Changelog v5: - Refactor the Tx/Rx DMA-based SPI transfers wait methods. - Add a new patch "spi: dw: Set xfer effective_speed_hz". - Add a new patch "spi: dw: Return any value retrieved from the dma_transfer callback" as a preparation patch before implementing the local DMA, Tx SPI and Rx SPI transfers wait methods. - Add a new patch "spi: dw: Locally wait for the DMA transactions completion", which provides a local DMA transaction complete method - Create a dedicated patch which adds the Rx-done wait method: "spi: dw: Add SPI Rx-done wait method to DMA-based transfer". - Add more detailed description of the problems the Tx/Rx-wait methods-related patches fix. - Wait for the SPI Tx and Rx transfers being finished in the mid_spi_dma_transfer() method executed in the task context. - Use spi_delay_exec() to wait for the SPI Tx/Rx completion, since now the driver calls the wait methods in the kernel thread context. - Use SPI_DELAY_UNIT_SCK spi_delay unit for Tx-wait delay, since SPI xfer's are now have the effective_speed_hz initialized. - Rx-wait for a delay correlated with the APB/SSI synchronous clock rate instead of using the SPI bus clock rate. Link: https://lore.kernel.org/linux-spi/20200529035915.20790-1-Sergey.Semin@baikalelectronics.ru Changelog v6: - Provide a more detailed description of the patch: 2901db35bea1 ("spi: dw: Locally wait for the DMA transfers completion") - Calculate the Rx delay with better accuracy by moving 4-multiplication to the head of the formulae: ns = 4U * NSEC_PER_SEC / dws->max_freq * nents. Co-developed-by:Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru> Signed-off-by:
Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru> Signed-off-by:
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Dinh Nguyen authored
Add optional reset property. Signed-off-by:
Dinh Nguyen <dinguyen@kernel.org> Link: https://lore.kernel.org/r/20200529155806.16758-2-dinguyen@kernel.orgSigned-off-by:
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Dinh Nguyen authored
Add mechanism to get the reset control and deassert it in order to bring the IP out of reset. Signed-off-by:
Liang Jin J <liang.j.jin@ericsson.com> Signed-off-by:
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Martin Sperl authored
bcm2711, Rasberry Pi 4's SoC, shares one interrupt for multiple instances of the bcm2835 SPI controller. So this enables shared interrupt support for them. The early bail out in the interrupt routine avoids messing with buffers of transfers being done by other means. Otherwise, the driver can handle receiving interrupts asserted by other controllers during an IRQ based transfer. Signed-off-by:
Martin Sperl <kernel@martin.sperl.org> Signed-off-by:
Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Tested-by:
Florian Fainelli <f.fainelli@gmail.com> Acked-by:
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Florian Fainelli authored
Make sure we clear the FIFOs, stop the block, disable the clock and release the DMA channel. Signed-off-by:
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Serge Semin authored
DebugFS kernel interface provides a dedicated method to create the registers dump file. Use it instead of creating a generic DebugFS file with manually written read callback function. Signed-off-by:
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Serge Semin authored
Since the common code in the spi-dw-dma.c driver is ready to be used by the MMIO driver and now provides a method to generically (on any DT or ACPI-based platforms) retrieve the Tx/Rx DMA channel handlers, we can use it and a set of the common DW SPI DMA callbacks to enable DMA at least for generic "snps,dw-apb-ssi" and "snps,dwc-ssi-1.01a" devices. Co-developed-by:
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Serge Semin authored
Since from now the former Intel MID platform layer is used as a generic DW SPI DMA module, let's alter the internal methods naming to be DMA-related instead of having the "mid_" prefix. Co-developed-by:
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Serge Semin authored
Seeing all of the DW SPI driver components like DW SPI DMA/PCI/MMIO depend on the DW SPI core code it's better to use the if-endif conditional kernel config statement to signify that common dependency. Co-developed-by:
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Serge Semin authored
Since there is a generic method available to initialize the DW SPI DMA interface on any DT and ACPI-based platforms, which in general can be designed with not only DW DMAC but with any DMA engine on board, we can freely remove the CONFIG_DW_DMAC_PCI config from dependency list of CONFIG_SPI_DW_DMA. Especially seeing that we don't use anything DW DMAC specific in the new driver. Co-developed-by:
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Serge Semin authored
This is a preparation patch before adding the DW DMA support into the DW SPI MMIO driver. We need to unpin the Non-DMA-specific code from the intended to be generic DW APB SSI DMA code. This isn't that hard, since the most part of the spi-dw-mid.c driver in fact implements a generic DMA interface for the DW SPI controller driver. The only Intel MID specifics concern getting the max frequency from the MRST Clock Control Unit and fetching the DMA controller channels from corresponding PCIe DMA controller. Since first one is related with the SPI interface configuration we moved it' implementation into the DW PCIe-SPI driver module. After that former spi-dw-mid.c file can be just renamed to be the DW SPI DMA module optionally compiled in to the DW APB SSI core driver. Co-developed-by:
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Serge Semin authored
Generic DMA support is going to be part of the DW APB SSI core object. In order to preserve the kernel loadable module name as spi-dw.ko, let's add the "-core" suffix to the object with generic DW APB SSI code and build it into the target spi-dw.ko driver. Suggested-by:
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Serge Semin authored
Tx-only DMA transfers are working perfectly fine since in this case the code just ignores the Rx FIFO overflow interrupts. But it turns out the SPI Rx-only transfers are broken since nothing pushing any data to the shift registers, so the Rx FIFO is left empty and the SPI core subsystems just returns a timeout error. Since DW DMAC driver doesn't support something like cyclic write operations of a single byte to a device register, the only way to support the Rx-only SPI transfers is to fake it by using a dummy Tx-buffer. This is what we intend to fix in this commit by setting the SPI_CONTROLLER_MUST_TX flag for DMA-capable platform. Signed-off-by:
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Serge Semin authored
Each channel of DMA controller may have a limited length of burst transaction (number of IO operations performed at ones in a single DMA client request). This parameter can be used to setup the most optimal DMA Tx/Rx data level values. In order to avoid the Tx buffer overrun we can set the DMA Tx level to be of FIFO depth minus the maximum burst transactions length. To prevent the Rx buffer underflow the DMA Rx level should be set to the maximum burst transactions length. This commit setups the DMA channels and the DW SPI DMA Tx/Rx levels in accordance with these rules. Signed-off-by:
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Serge Semin authored
It isn't good to have numeric literals in the code especially if there are multiple of them and they are related. Let's replace the Tx and Rx burst level literals with the corresponding constants. Co-developed-by:
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Serge Semin authored
Having any data left in the Rx FIFO after the DMA engine claimed it has finished all DMA transactions is an abnormal situation, since the DW SPI controller driver expects to have all the data being fetched and placed into the SPI Rx buffer at that moment. In case if that has happened we hopefully assume that the DMA engine may still be doing the data fetching, thus we give it sometime to finish. If after a short period of time the data is still left in the Rx FIFO, the driver will give up waiting and return an error indicating that the SPI controller/DMA engine must have hung up or failed at some point of doing their duties. Fixes: 7063c0d9 ("spi/dw_spi: add DMA support") Co-developed-by:
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Serge Semin authored
Since DMA transfers are performed asynchronously with actual SPI bus transfers, then even if DMA transactions are finished it doesn't mean all data is actually pushed to the SPI bus. Some data might still be in the controller FIFO. This is specifically true for Tx-only transfers. In this case if the next SPI transfer is recharged while a tail of the previous one is still in FIFO, we'll loose that tail data. In order to fix that problem let's add the wait procedure of the Tx SPI transfer completion after the DMA transactions are finished. Fixes: 7063c0d9 ("spi/dw_spi: add DMA support") Co-developed-by:
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Serge Semin authored
In general each DMA-based SPI transfer can be split up into two stages: DMA data transmission/reception and SPI-bus transmission/reception. DMA asynchronous transactions completion can be tracked by means of the DMA async Tx-descriptor completion callback. But that callback being called indicates that the DMA transfer has been finished, it doesn't mean that SPI data transmission is also done. Moreover in fact it isn't for at least Tx-only SPI transfers. Upon DMA transfer completion some data is left in the Tx FIFO and being pushed out by the SPI controller. So in order to make sure that an SPI transfer is completely pushed to the SPI-bus, the driver has to wait for both DMA transaction and the SPI-bus transmission/reception are finished. Note if there is a way to asynchronously track the former event by means of the DMA async Tx callback, there isn't easy one for the later (IRQ-based solution won't work since SPI controller doesn't notify about Rx FIFO being empty). The DMA transfer completion callback isn't suitable to wait for the SPI controller activity finish either. The callback might (in case of DW DMAC it will) be called in the tasklet context. Waiting for the SPI controller to complete the transfer might take a considerable amount of time since SPI-bus might be pretty slow. In this case delaying the execution in the tasklet atomic context might cause significant system performance drop. So to speak the best option we've got to solve the problem is to consequently wait for both stages being finished in the locally implemented SPI transfer execution procedure even if it costs us of the local wait-function re-implementation. In this case we don't need to use the SPI-core transfer-wait functionality, but we'll make sure that all DMA and SPI-bus transactions are completely finished before the SPI-core transfer_one callback returns. In this commit we provide an implementation of the DMA-transfers completion wait functionality. The DW APB SSI DMA-specific SPI transfer_one function waits for both Tx and Rx DMA transfers being finished, and only then exits with zero returned signalling to the SPI core that the SPI transfer is finished. This implementation is fully equivalent to the currently used DMA-execution-SPI-core-wait algorithm. The SPI-bus transmission/reception wait methods will be added in the follow-up commits. Signed-off-by:
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Serge Semin authored
DW APB SSI DMA-part of the driver may need to perform the requested SPI-transfer synchronously. In that case the dma_transfer() callback will return 0 as a marker of the SPI transfer being finished so the SPI core doesn't need to wait and may proceed with the SPI message trasnfers pumping procedure. This will be needed to fix the problem when DMA transactions are finished, but there is still data left in the SPI Tx/Rx FIFOs being sent/received. But for now make dma_transfer to return 1 as the normal dw_spi_transfer_one() method. Signed-off-by:
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