- 08 Oct, 2020 1 commit
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Serge Semin authored
Simplify the dw_spi_add_host() method a bit by replacing the currently implemented default set_cs callback setting up and later having it overwritten by a custom function with direct if-else-based callback assignment. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20201007235511.4935-2-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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- 06 Oct, 2020 4 commits
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Ikjoon Jang authored
This patch adds dev_pm_ops to mtk-nor to support suspend/resume, auto suspend delay is set to -1 by default. Accessing registers are only permitted after its clock is enabled to deal with unknown state of operating clk at probe time. Signed-off-by:
Ikjoon Jang <ikjn@chromium.org> Link: https://lore.kernel.org/r/20201006155010.v5.4.I68983b582d949a91866163bab588ff3c2a0d0275@changeidSigned-off-by:
Mark Brown <broonie@kernel.org>
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Ikjoon Jang authored
This patch enables 36bit dma address support to spi-mtk-nor. Currently this is enabled only for mt8192-nor. Signed-off-by:
Ikjoon Jang <ikjn@chromium.org> Link: https://lore.kernel.org/r/20201006155010.v5.3.Id1cb208392928afc7ceed4de06924243c7858cd0@changeidSigned-off-by:
Mark Brown <broonie@kernel.org>
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Ikjoon Jang authored
Use dma_alloc_coherent() for bounce buffer instead of kmalloc() to make sure the bounce buffer to be allocated within its DMAable range. Signed-off-by:
Ikjoon Jang <ikjn@chromium.org> Link: https://lore.kernel.org/r/20201006155010.v5.2.I06cb65401ab5ad63ea30c4788d26633928d80f38@changeidSigned-off-by:
Mark Brown <broonie@kernel.org>
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Ikjoon Jang authored
Add MT8192 spi-nor controller support. Signed-off-by:
Ikjoon Jang <ikjn@chromium.org> Acked-by:
Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20201006155010.v5.1.I4cd089ef1fe576535c6b6e4f1778eaab1c4441cf@changeidSigned-off-by:
Mark Brown <broonie@kernel.org>
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- 05 Oct, 2020 1 commit
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Geert Uytterhoeven authored
Document R-Car M3-W+ (R8A77961) SoC bindings. Signed-off-by:
Geert Uytterhoeven <geert+renesas@glider.be> Link: https://lore.kernel.org/r/20201005112549.22222-1-geert+renesas@glider.beSigned-off-by:
Mark Brown <broonie@kernel.org>
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- 02 Oct, 2020 9 commits
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Łukasz Stelmach authored
s3c64xx_spi_hwinit() disables interrupts. In s3c64xx_spi_probe() after calling s3c64xx_spi_hwinit() they are enabled with the following call. Reviewed-by:
Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by:
Łukasz Stelmach <l.stelmach@samsung.com> Link: https://lore.kernel.org/r/20201002122243.26849-10-l.stelmach@samsung.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Łukasz Stelmach authored
Increase timeout by 30 ms for some wiggle room and set the minimum value to 100 ms. This ensures a non-zero value for short transfers which may take less than 1 ms. The timeout value does not affect performance because it is used with a completion. Similar formula is used in other drivers e.g. sun4i, sun6i. Reviewed-by:
Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by:
Łukasz Stelmach <l.stelmach@samsung.com> Link: https://lore.kernel.org/r/20201002122243.26849-9-l.stelmach@samsung.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Łukasz Stelmach authored
Make sure the cur_speed value used in s3c64xx_enable_datapath() to configure DMA channel and in s3c64xx_wait_for_*() to calculate the transfer timeout is set to the actual value of (half) the clock speed. Don't change non-CMU case, because no frequency calculation errors have been reported. Reviewed-by:
Krzysztof Kozlowski <krzk@kernel.org> Suggested-by:
Tomasz Figa <tomasz.figa@gmail.com> Signed-off-by:
Łukasz Stelmach <l.stelmach@samsung.com> Link: https://lore.kernel.org/r/20201002122243.26849-8-l.stelmach@samsung.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Łukasz Stelmach authored
Remove descriptions for non-existent fields and fix indentation. Reviewed-by:
Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by:
Łukasz Stelmach <l.stelmach@samsung.com> Link: https://lore.kernel.org/r/20201002122243.26849-7-l.stelmach@samsung.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Łukasz Stelmach authored
Rename S3C64XX_SPI_SLAVE_* to S3C64XX_SPI_CS_* to match documentation. Signed-off-by:
Łukasz Stelmach <l.stelmach@samsung.com> Reviewed-by:
Krzysztof Kozlowski <krzk@kernel.org> Link: https://lore.kernel.org/r/20201002122243.26849-6-l.stelmach@samsung.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Łukasz Stelmach authored
Report amount of pending data when a transfer stops due to errors. Report if DMA was used to transfer data and print the status code. Reviewed-by:
Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by:
Łukasz Stelmach <l.stelmach@samsung.com> Link: https://lore.kernel.org/r/20201002122243.26849-5-l.stelmach@samsung.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Łukasz Stelmach authored
Check return values in prepare_dma() and s3c64xx_spi_config() and propagate errors upwards. Fixes: 78843727 ("spi: s3c64xx: move to generic dmaengine API") Reviewed-by:
Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by:
Łukasz Stelmach <l.stelmach@samsung.com> Link: https://lore.kernel.org/r/20201002122243.26849-4-l.stelmach@samsung.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Łukasz Stelmach authored
Fix issues with DMA transfers bigger than 512 bytes on Exynos3250. Without the patches such transfers fail. The vendor kernel for ARTIK5 handles CS in a simmilar way. Signed-off-by:
Łukasz Stelmach <l.stelmach@samsung.com> Reviewed-by:
Krzysztof Kozlowski <krzk@kernel.org> Link: https://lore.kernel.org/r/20201002122243.26849-3-l.stelmach@samsung.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Łukasz Stelmach authored
Fix issues with DMA transfers bigger than 512 bytes on Exynos3250. Without the patches such transfers fail to complete. This solution to the problem is found in the vendor kernel for ARTIK5 boards based on Exynos3250. Reviewed-by:
Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by:
Łukasz Stelmach <l.stelmach@samsung.com> Link: https://lore.kernel.org/r/20201002122243.26849-2-l.stelmach@samsung.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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- 01 Oct, 2020 7 commits
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Mark Brown authored
Merge series "spi: spi-mtk-nor: make use of full capability of program mode" from Chuanhong Guo <gch981213@gmail.com>: "program" mode on this controller can trigger up to 56 bits of data shifting. During the operation, data in PRGDATA[0-5] will be shifted out from MOSI, and data from MISO will be continuously filling SHREG[0-9]. Currently this mode is used to implement transfer_one_message for 6-byte full-duplex transfer, but it can execute a transfer for up-to 7 bytes as long as the last byte is read only. transfer_one_message is expected to perform full-duplex transfer, instead of transfer with specific format. mtk_nor_spi_mem_prg is added here to use this extra byte. Newer version of this controller can trigger longer data shifting with shift bytes more than PRGDATA_MAX + SHREG_MAX. This patch is implemented with that in mind and it checks against both SHREG_MAX and PRG_CNT_MAX for future support of new controllers. Patch 3/3 is a fix for: commit a59b2c7c ("spi: spi-mtk-nor: support standard spi properties") which breaks supports_op logic. But it can't be separated as it depends on patch 2/3. Fortuantely the broken commit isn't in stable yet. Chuanhong Guo (3): spi: spi-mtk-nor: make use of full capability of prg mode spi: spi-mtk-nor: add helper for checking prg mode ops spi: spi-mtk-nor: fix op checks in supports_op drivers/spi/spi-mtk-nor.c | 179 +++++++++++++++++++++++++++++++++----- 1 file changed, 158 insertions(+), 21 deletions(-) -- 2.26.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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Barry Song authored
Running in hardIRQ, disabling IRQ is redundant. Signed-off-by:
Barry Song <song.bao.hua@hisilicon.com> Link: https://lore.kernel.org/r/20200926001616.21292-2-song.bao.hua@hisilicon.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Barry Song authored
Running in hardIRQ, disabling IRQ is redundant. Signed-off-by:
Barry Song <song.bao.hua@hisilicon.com> Link: https://lore.kernel.org/r/20200926001616.21292-1-song.bao.hua@hisilicon.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Thomas Kopp authored
This patch implements the reporting of the effectively used speed_hz for the transfer by setting xfer->effective_speed_hz. See the following patch, which adds this feature to the SPI core for more information: commit 5d7e2b5e ("spi: core: allow reporting the effectivly used speed_hz for a transfer") Signed-off-by:
Thomas Kopp <thomas.kopp@microchip.com> Reviewed-by:
Tudor Ambarus <tudor.ambarus@microchip.com> Link: https://lore.kernel.org/r/20200921071036.2091-1-thomas.kopp@microchip.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Chuanhong Guo authored
commit a59b2c7c ("spi: spi-mtk-nor: support standard spi properties") tries to inverse the logic of supports_op when adding spi_mem_default_supports_op check, but it didn't get it done properly. There are two regressions introduced by this commit: 1. reading ops supported by program mode is rejected. 2. all ops with special controller routines are incorrectly further checked against program mode. This commits inverses the logic back: 1. check spi_mem_default_supports_op and reject unsupported ops first. 2. return true for ops with special controller routines. 3. check the left ops against controller program mode. Fixes: a59b2c7c ("spi: spi-mtk-nor: support standard spi properties") Signed-off-by:
Chuanhong Guo <gch981213@gmail.com> Link: https://lore.kernel.org/r/20200924152730.733243-4-gch981213@gmail.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Chuanhong Guo authored
op checking/resizing logic for the newly added mtk_nor_spi_mem_prg is more complicated. Add two helper functions for them: mtk_nor_match_prg: check whether an op is supported by prg mode. mtk_nor_adj_prg_size: adjust data size for mtk_nor_spi_mem_prg. mtk_nor_match_prg isn't called yet because supports_op is currently broken. It'll be used in the next fix commit. Signed-off-by:
Chuanhong Guo <gch981213@gmail.com> Link: https://lore.kernel.org/r/20200924152730.733243-3-gch981213@gmail.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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Chuanhong Guo authored
"program" mode on this controller can trigger up to 56 bits of data shifting. During the operation, data in PRGDATA[0-5] will be shifted out from MOSI, and data from MISO will be continuously filling SHREG[0-9]. Currently this mode is used to implement transfer_one_message for 6-byte full-duplex transfer, but it can execute a transfer for up-to 7 bytes as long as the last byte is read only. transfer_one_message is expected to perform full-duplex transfer, instead of transfer with specific format. mtk_nor_spi_mem_prg is added here to use this extra byte. Newer version of this controller can trigger longer data shifting with shift bytes more than PRGDATA_MAX + SHREG_MAX. This patch is implemented with that in mind and it checks against both SHREG_MAX and PRG_CNT_MAX for future support of new controllers. Signed-off-by:
Chuanhong Guo <gch981213@gmail.com> Link: https://lore.kernel.org/r/20200924152730.733243-2-gch981213@gmail.comSigned-off-by:
Mark Brown <broonie@kernel.org>
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- 29 Sep, 2020 18 commits
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Mark Brown authored
Merge series "spi: dw: Add full Baikal-T1 SPI Controllers support" from Serge Semin <Sergey.Semin@baikalelectronics.ru>: Originally I intended to merge a dedicated Baikal-T1 System Boot SPI Controller driver into the kernel and leave the DW APB SSI driver untouched. But after a long discussion (see the link at the bottom of the letter) Mark and Andy persuaded me to integrate what we developed there into the DW APB SSI core driver to be useful for another controllers, which may have got the same peculiarities/problems as ours: - No IRQ. - No DMA. - No GPIO CS, so a native CS is utilized. - small Tx/Rx FIFO depth. - Automatic CS assertion/de-assertion. - Slow system bus. All of them have been fixed in the framework of this patchset in some extent at least for the SPI memory operations. As I expected it wasn't that easy and the integration took that many patches as you can see from the subject. Though some of them are mere cleanups or weakly related with the subject fixes, but we just couldn't leave the code as is at some places since we were working with the DW APB SSI driver anyway. Here is what we did to fix the original DW APB SSI driver, to make it less messy. First two patches are just cleanups to simplify the DW APB SSI device initialization a bit. We suggest to discard the IRQ threshold macro as unused and use a ternary operator to initialize the set_cs callback instead of assigning-and-updating it. Then we've discovered that the n_bytes field of the driver private data is used by the DW APB SSI IRQ handler, which requires it to be initialized before the SMP memory barrier and to be visible from another CPUs. Speaking about the SMP memory barrier. Having one right after the shared resources initialization is enough and there is no point in using the spin-lock to protect the Tx/Rx buffer pointers. The protection functionality is redundant there by the driver design. (Though I have a doubt whether the SMP memory barrier is also required there because the normal IO-methods like readl/writel implies a full memory barrier. So any memory operations performed before them are supposed to be seen by devices and another CPUs. See the patch log for details of my concern.) Thirdly we've found out that there is some confusion in the IRQs masking/unmasking/clearing in the SPI-transfer procedure. Multiple interrupts are unmasked on the SPI-transfer initialization, but just TXEI is only masked back on completion. Similarly IRQ status isn't cleared on the controller reset, which actually makes the reset being not full and errors prone in the controller probe procedure. Another very important optimization is using the IO-relaxed accessors in the dw_read_io_reg()/dw_write_io_reg() methods. Since the Tx/Rx FIFO data registers are the most frequently accessible controller resource, using relaxed accessors there will significantly improve the data read/write performance. At least on Baikal-T1 SoC such modification opens up a way to have the DW APB SSI controller working with higher SPI bus speeds, than without it. Fifthly we've made an effort to cleanup the code using the SPI-device private data - chip_data. We suggest to remove the chip type from there since it isn't used and isn't implemented right anyway. Then instead of having a bus speed, clock divider, transfer mode preserved there, and recalculating the CR0 fields of the SPI-device-specific phase, polarity and frame format each time the SPI transfer is requested, we can save it in the chip_data instance. By doing so we'll make that structure finally used as it was supposed to by design (see the spi-fsl-dspi.c, spi-pl022.c, spi-pxa2xx.c drivers for examples). Sixthly instead of having the SPI-transfer specific CR0-update callback, we suggest to implement the DW APB SSI controller capabilities approach. By doing so we can now inject the vendor-specific peculiarities in different parts of the DW APB SSI core driver (which is required to implement both SPI-transfers and the SPI memory operations). This will also make the code less confusing like defining a callback in the core driver, setting it up in the glue layer, then calling it from the core driver again. Seeing the small capabilities implementation embedded in-situ is more readable than tracking the callbacks assignments. This will concern the CS-override, Keembay master setup, DW SSI-specific CR0 registers layout capabilities. Seventhly since there are going to be two types of the transfers implemented in the DW APB SSI core driver, we need a common method to set the controller configuration like, Tx/Rx-mode, bus speed, data frame size and number of data frames to read in case of the memory operations. So we just detached the corresponding code from the SPI-transfer-one method and made it to be a part of the new dw_spi_update_config() function, which is former update_cr0(). Note that the new method will be also useful for the glue drivers, which due to the hardware design need to create their own memory operations (for instance, for the dirmap-operations provided in the Baikal-T System Boot SPI controller driver). Eighthly it is the data IO procedure and IRQ-based SPI-transfer implementation refactoring. The former one will look much simpler if the buffers initial pointers and the buffers length data utilized instead of the Tx/Rx buffers start and end pointers. The later one currently lacks of valid execution at the final stage of the SPI-transfer. So if there is no data left to send, but there is still data which needs to be received, the Tx FIFO Empty IRQ will constantly happen until all of the requested inbound data is received. So we suggest to fix that by taking the Rx FIFO Empty IRQ into account. Ninthly it's potentially errors prone to enable the DW APB SSI interrupts before enabling the chip. It specifically concerns a case if for some reason the DW APB SSI IRQs handler is executed before the controller is enabled. That will cause a part of the outbound data loss. So we suggest to reverse the order. Tenthly in order to be able to pre-initialize the Tx FIFO with data and only the start the SPI memory operations we need to have any CS de-activated. We'll fulfil that requirement by explicitly clearing the CS on the SPI transfer completion and at the explicit controller reset. Then seeing all the currently available and potentially being created types of the SPI transfers need to perform the DW APB SSI controller status register check and the errors handler procedure, we've created a common method for all of them. Eleventhly if before we've mostly had a series of fixups, cleanups and refactorings, here we've finally come to the new functionality implementation. It concerns the poll-based transfer (as Baikal-T1 System Boot SPI controller lacks a dedicated IRQ lane connected) and the SPI memory operations implementation. If the former feature is pretty much straightforward (see the patch log for details), the later one is a bit tricky. It's based on the EEPROM-read (write-then-read) and the Tx-only modes of the DW APB SSI controller, which as performing the automatic data read and write let's us to implement the faster IO procedure than using the Tx-Rx-mode-based approach. Having the memory-operations implemented that way is the best thing we can currently do to provide the errors-less SPI transfers to SPI devices with native CS attached. Note the approach utilized here to develop the SPI memory operations can be also used to create the "automatic CS toggle problem"-free(ish) SPI transfers (combine SPI-message transfers into two buffers, disable interrupts, push-pull the combined data). But we don't provide a solution in the framework of this patchset. It is a matter of a dedicated one, which we currently don't intend to spend our time on. Finally at the closure of the this patchset you'll find patches, which provide the Baikal-T1-specific DW APB SSI controllers support. The SoC has got three SPI controllers. Two of them are pretty much normal DW APB SSI interfaces: with IRQ, DMA, FIFOs of 64 words depth, 4x CSs. But the third one as being a part of the Baikal-T1 System Boot Controller has got a very limited resources: no IRQ, no DMA, only a single native chip-select and Tx/Rx FIFOs with just 8 words depth available. In order to provide a transparent initial boot code execution the System Boot SPI Controller is also utilized by an vendor-specific IP-block, which exposes an SPI flash memory direct mapping interface. Please see the corresponding patch for details. Link: https://lore.kernel.org/linux-spi/20200508093621.31619-1-Sergey.Semin@baikalelectronics.ru/ [1] "LINUX KERNEL MEMORY BARRIERS", Documentation/memory-barriers.txt, Section "KERNEL I/O BARRIER EFFECTS" Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru> Cc: Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Lars Povlsen <lars.povlsen@microchip.com> Cc: wuxu.wu <wuxu.wu@huawei.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-spi@vger.kernel.org Cc: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org Serge Semin (30): spi: dw: Discard IRQ threshold macro spi: dw: Use ternary op to init set_cs callback spi: dw: Initialize n_bytes before the memory barrier Revert: spi: spi-dw: Add lock protect dw_spi rx/tx to prevent concurrent calls spi: dw: Clear IRQ status on DW SPI controller reset spi: dw: Disable all IRQs when controller is unused spi: dw: Use relaxed IO-methods to access FIFOs spi: dw: Discard DW SSI chip type storages spi: dw: Convert CS-override to DW SPI capabilities spi: dw: Add KeemBay Master capability spi: dw: Add DWC SSI capability spi: dw: Detach SPI device specific CR0 config method spi: dw: Update SPI bus speed in a config function spi: dw: Simplify the SPI bus speed config procedure spi: dw: Update Rx sample delay in the config function spi: dw: Add DW SPI controller config structure spi: dw: Refactor data IO procedure spi: dw: Refactor IRQ-based SPI transfer procedure spi: dw: Perform IRQ setup in a dedicated function spi: dw: Unmask IRQs after enabling the chip spi: dw: Discard chip enabling on DMA setup error spi: dw: De-assert chip-select on reset spi: dw: Explicitly de-assert CS on SPI transfer completion spi: dw: Move num-of retries parameter to the header file spi: dw: Add generic DW SSI status-check method spi: dw: Add memory operations support spi: dw: Introduce max mem-ops SPI bus frequency setting spi: dw: Add poll-based SPI transfers support dt-bindings: spi: dw: Add Baikal-T1 SPI Controllers spi: dw: Add Baikal-T1 SPI Controller glue driver .../bindings/spi/snps,dw-apb-ssi.yaml | 33 +- drivers/spi/Kconfig | 29 + drivers/spi/Makefile | 1 + drivers/spi/spi-dw-bt1.c | 339 +++++++++ drivers/spi/spi-dw-core.c | 642 ++++++++++++++---- drivers/spi/spi-dw-dma.c | 16 +- drivers/spi/spi-dw-mmio.c | 36 +- drivers/spi/spi-dw.h | 85 ++- 8 files changed, 960 insertions(+), 221 deletions(-) create mode 100644 drivers/spi/spi-dw-bt1.c -- 2.27.0
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Serge Semin authored
There is no point in having the commit 19b61392 ("spi: spi-dw: Add lock protect dw_spi rx/tx to prevent concurrent calls") applied. The commit author made an assumption that the problem with the rx data mismatch was due to the lack of the data protection. While most likely it was caused by the lack of the memory barrier. So having the commit bfda0445 ("spi: dw: use "smp_mb()" to avoid sending spi data error") applied would be enough to fix the problem. Indeed the spin unlock operation makes sure each memory operation issued before the release will be completed before it's completed. In other words it works as an implicit one way memory barrier. So having both smp_mb() and the spin_unlock_irqrestore() here is just redundant. One of them would be enough. It's better to leave the smp_mb() since the Tx/Rx buffers consistency is provided by the data transfer algorithm implementation: first we initialize the buffers pointers, then make sure the assignments are visible by the other CPUs by calling the smp_mb(), only after that enable the interrupt, which handler uses the buffers. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112914.26501-5-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
In a further commit we'll have to get rid of the update_cr0() callback and define a DW SSI capability instead. Since Keem Bay master/slave functionality is controller by the CTRL0 register bitfield, we need to first move the master mode selection into the internal corresponding update_cr0 method, which would be activated by means of the dedicated DW_SPI_CAP_KEEMBAY_MST capability setup. Note this will be also useful if the driver will be ever altered to support the DW SPI slave interface. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112914.26501-11-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
There are several vendor-specific versions of the DW SPI controllers, each of which may have some peculiarities with respect to the original IP-core. Seeing it has already caused adding flags and a callback into the DW SPI private data, let's introduce a generic capabilities interface to tune the generic DW SPI controller driver up in accordance with the particular controller specifics. It's done by converting a simple Alpine-specific CS-override capability into the DW SPI controller capability activated by setting the DW_SPI_CAP_CS_OVERRIDE flag. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112914.26501-10-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
Keeping SPI peripheral devices type is pointless since first it hasn't been functionally utilized by any of the client drivers/code and second it won't work for Microwire type at the very least. Moreover there is no point in setting up the type by means of the chip-data in the modern kernel. The peripheral devices with specific interface type need to be detected in order to activate the corresponding frame format. It most likely will require some peripheral device specific DT property or whatever to find out the interface protocol. So let's remove the serial interface type fields from the DW APB SSI controller and the SPI peripheral device private data. Note we'll preserve the explicit SSI_MOTO_SPI interface type setting up to signify the only currently supported interface protocol. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112914.26501-9-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
In accordance with [1] the relaxed methods are guaranteed to be ordered with respect to other accesses from the same CPU thread to the same peripheral. This is what we need during the data read/write from/to the controller FIFOs being executed within a single IRQ handler or a kernel task. Such optimization shall significantly speed the data reader and writer up. For instance, the relaxed IO-accessors utilization on Baikal-T1 lets the driver to support the SPI memory operations with bus frequency three-fold faster than if normal IO-accessors would be used. [1] "LINUX KERNEL MEMORY BARRIERS", Documentation/memory-barriers.txt, Section "KERNEL I/O BARRIER EFFECTS" Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112914.26501-8-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
It's a good practice to disable all IRQs if a device is fully unused. In our case it is supposed to be done before requesting the IRQ and after the last byte of an SPI transfer is received. In the former case it's required to prevent the IRQ handler invocation before the driver data is fully initialized (which may happen if the IRQs status has been left uncleared before the device is probed). So we just moved the spi_hw_init() method invocation to the earlier stage before requesting the IRQ. In the later case there is just no point in having any of the IRQs enabled between SPI transfers and when there is no SPI message currently being processed. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112914.26501-7-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
It turns out the IRQ status isn't cleared after switching the controller off and getting it back on, which may cause raising false error interrupts if controller has been unsuccessfully used by, for instance, a bootloader before the driver is loaded. Let's explicitly clear the interrupts status in the dedicated controller reset method. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112914.26501-6-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
Since n_bytes field of the DW SPI private data is also utilized by the IRQ handler, we need to make sure it' initialization is done before the memory barrier. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112914.26501-4-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
The macro has been unused since a half of FIFO length was defined to be a marker of the IRQ. Let's remove it definition. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112914.26501-2-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
In case if at least one of the requested DMA engine channels doesn't support the hardware accelerated SG list entries traverse, the DMA driver will most likely work that around by performing the IRQ-based SG list entries resubmission. That might and will cause a problem if the DMA Tx channel is recharged and re-executed before the Rx DMA channel. Due to non-deterministic IRQ-handler execution latency the DMA Tx channel will start pushing data to the SPI bus before the Rx DMA channel is even reinitialized with the next inbound SG list entry. By doing so the DMA Tx channel will implicitly start filling the DW APB SSI Rx FIFO up, which while the DMA Rx channel being recharged and re-executed will eventually be overflown. In order to solve the problem we have to feed the DMA engine with SG list entries one-by-one. It shall keep the DW APB SSI Tx and Rx FIFOs synchronized and prevent the Rx FIFO overflow. Since in general the SPI tx_sg and rx_sg lists may have different number of entries of different lengths (though total length should match) we virtually split the SG-lists to the set of DMA transfers, which length is a minimum of the ordered SG-entries lengths. The solution described above is only executed if a full-duplex SPI transfer is requested and the DMA engine hasn't provided channels with hardware accelerated SG list traverse capability to handle both SG lists at once. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Suggested-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200920112322.24585-12-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
In order to use the DMA submission and waiting methods in both generic DMA-based SPI transfer and one-by-one DMA SG entries transmission functions, we need to modify the dw_spi_dma_wait() and dw_spi_dma_submit_tx()/dw_spi_dma_submit_rx() prototypes. So instead of getting the SPI transfer object as the second argument they must accept the exact data structure instances they imply to use. Those are the current transfer length and the SPI bus frequency in case of dw_spi_dma_wait(), and SG list together with number of list entries in case of the DMA Tx/Rx submission methods. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112322.24585-11-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
DW APB SSI DMA driver doesn't use the native SPI core wait API since commit bdbdf0f0 ("spi: dw: Locally wait for the DMA transfers completion"). Due to that the driver can now clear the DMAC register in a single place synchronously with the DMA transactions completion or failure. After that all the possible code paths are still covered: 1) DMA completion callbacks are executed in case if the corresponding DMA transactions are finished. When they are, one of them will eventually wake the SPI messages pump kernel thread and dw_spi_dma_transfer_all() method will clean the DMAC register as implied by this patch. 2) dma_stop is called when the SPI core detects an error either returned from the transfer_one() callback or set in the SPI message status field. Both types of errors will be noticed by the dw_spi_dma_transfer_all() method. 3) dma_exit is called when either SPI controller driver or the corresponding device is removed. In any case the SPI core will first flush the SPI messages pump kernel thread, so any pending or in-fly SPI transfers will be finished before that. Due to all of that let's simplify the DW APB SSI DMA driver a bit and move the DMAC register cleanup to a single place in the dw_spi_dma_transfer_all() method. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112322.24585-10-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
In order to add an alternative method of DMA-based SPI transfer first we need to detach the currently available one from the common code. Here we move the normal DMA-based SPI transfer execution functionality into a dedicated method. It will be utilized if either the DMA engine supports an unlimited number SG entries or Tx-only SPI transfer is requested. But currently just use it for any SPI transfer. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112322.24585-9-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
It's pointless to pass the Rx and Tx transfers DMA Tx-descriptors, since they are used in the Tx/Rx submit method only. Instead just return the submission status from these methods. This alteration will make the code less complex. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112322.24585-8-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
We suggest to add the dmaengine_submit() return value test for errors. It has been unnecessary while the driver was expected to be utilized in pair with DW DMAC. But since now the driver can be used with any DMA engine, it might be useful to track the errors on DMA submissions so not miss them and get into an unpredictable driver behaviour. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112322.24585-7-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
Indeed we can freely move the dmaengine_submit() method invocation and the Tx and Rx busy flag setting into the DMA Tx/Rx prepare methods. Since the Tx/Rx preparation method is now mainly used for the DMA transfers submission, here we suggest to rename it to have the _submit_{r,t}x suffix instead. By having this alteration applied first we implement another code preparation before adding the one-by-one DMA SG entries transmission, second we now have the dma_async_tx_descriptor descriptor used locally only in the new DMA transfers submission methods (this will be cleaned up a bit later), third we make the generic transfer method more readable, where now the functionality of submission, execution and wait procedures is transparently split up instead of having a preparation, intermixed submission/execution and wait procedures. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112322.24585-6-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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Serge Semin authored
Checking rx_buf for being NULL and returning NULL from the Rx-channel preparation method doesn't let us to distinguish that situation from errors happening during the Rx SG-list preparation. So it's better to make sure that the rx_buf not-NULL and full-duplex communication is requested prior calling the Rx preparation method. Signed-off-by:
Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200920112322.24585-5-Sergey.Semin@baikalelectronics.ruSigned-off-by:
Mark Brown <broonie@kernel.org>
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