Re: [PATCH v2 00/19] spi: dw: Add generic DW DMA controller support

[Serge Semin <Sergey.Semin@baikalelectronics.ru>]

On Fri, May 15, 2020 at 02:49:50PM +0300, Andy Shevchenko wrote:
> On Fri, May 15, 2020 at 01:47:39PM +0300, Serge Semin wrote:
> > 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")
> 
> Thanks! I'm going to review it soon.
> 
> Hint for the next time, please start always a new thread with new version.

Thanks for suggestion. Indeed my knowledge of the submission procedure has
been incomplete: "However, for a multi-patch series, it is generally best
to avoid using In-Reply-To: to link to older versions of the series.
This way multiple versions of the patch don't become an unmanageable
forest of references in email clients." [1]

[1] Documentation/process/submitting-patches.rst

-Sergey

> 
> > Co-developed-by: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
> > Signed-off-by: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
> > Co-developed-by: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
> > Signed-off-by: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
> > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> > Cc: Maxim Kaurkin <Maxim.Kaurkin@baikalelectronics.ru>
> > Cc: Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>
> > Cc: Ekaterina Skachko <Ekaterina.Skachko@baikalelectronics.ru>
> > Cc: Vadim Vlasov <V.Vlasov@baikalelectronics.ru>
> > Cc: Alexey Kolotnikov <Alexey.Kolotnikov@baikalelectronics.ru>
> > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> > Cc: Paul Burton <paulburton@kernel.org>
> > Cc: Ralf Baechle <ralf@linux-mips.org>
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Allison Randal <allison@lohutok.net>
> > Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Cc: Gareth Williams <gareth.williams.jx@renesas.com>
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: linux-mips@vger.kernel.org
> > Cc: linux-spi@vger.kernel.org
> > Cc: devicetree@vger.kernel.org
> > Cc: linux-kernel@vger.kernel.org
> > 
> > ---
> > 
> > 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.
> > 
> > Serge Semin (19):
> >   dt-bindings: spi: dw: Add Tx/Rx DMA properties
> >   spi: dw: Add Tx/Rx finish wait methods to the MID DMA
> >   spi: dw: Clear DMAC register when done or stopped
> >   spi: dw: Fix native CS being unset
> >   spi: dw: Enable interrupts in accordance with DMA xfer mode
> >   spi: dw: Discard static DW DMA slave structures
> >   spi: dw: Discard unused void priv pointer
> >   spi: dw: Discard dma_width member of the dw_spi structure
> >   spi: dw: Parameterize the DMA Rx/Tx burst length
> >   spi: dw: Use DMA max burst to set the request thresholds
> >   spi: dw: Initialize paddr in DW SPI MMIO private data
> >   spi: dw: Fix Rx-only DMA transfers
> >   spi: dw: Move Non-DMA code to the DW PCIe-SPI driver
> >   spi: dw: Remove DW DMA code dependency from DW_DMAC_PCI
> >   spi: dw: Add DW SPI DMA/PCI/MMIO dependency on the DW SPI core
> >   spi: dw: Cleanup generic DW DMA code namings
> >   spi: dw: Add DMA support to the DW SPI MMIO driver
> >   spi: dw: Use regset32 DebugFS method to create regdump file
> >   dt-bindings: spi: Convert DW SPI binding to DT schema
> > 
> >  .../bindings/spi/snps,dw-apb-ssi.txt          |  42 ---
> >  .../bindings/spi/snps,dw-apb-ssi.yaml         | 127 +++++++++
> >  .../devicetree/bindings/spi/spi-dw.txt        |  24 --
> >  drivers/spi/Kconfig                           |  15 +-
> >  drivers/spi/Makefile                          |   7 +-
> >  drivers/spi/{spi-dw-mid.c => spi-dw-dma.c}    | 257 ++++++++++--------
> >  drivers/spi/spi-dw-mmio.c                     |   9 +-
> >  drivers/spi/spi-dw-pci.c                      |  50 +++-
> >  drivers/spi/spi-dw.c                          |  98 +++----
> >  drivers/spi/spi-dw.h                          |  33 ++-
> >  10 files changed, 405 insertions(+), 257 deletions(-)
> >  delete mode 100644 Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt
> >  create mode 100644 Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml
> >  delete mode 100644 Documentation/devicetree/bindings/spi/spi-dw.txt
> >  rename drivers/spi/{spi-dw-mid.c => spi-dw-dma.c} (53%)
> > 
> > -- 
> > 2.25.1
> > 
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
>