Re: [PATCH v3 0/9] R-Car Gen2 DMA Controller driver

[Simon Horman <horms@verge.net.au>]

On Sun, Oct 26, 2014 at 07:40:07PM +0200, Laurent Pinchart wrote:
> Hello,
> 
> This patch sets adds a new driver for the DMA controller found in the R-Car
> Gen2 SoCs under the name "Direct Memory Access Controller for System
> (SYS-DMAC)". Support for the "Realtime Direct Memory Access Controller
> (RT-DMAC)" and "Direct Memory Access Controller for Audio (Audio-DMAC)" will
> be added later.
> 
> For the rationale of why a new driver is needed, and performance figures,
> please see the cover letter of v1 ("[PATCH 0/7] R-Car Gen2 DMA Controller
> driver") [1].
> 
> Support for hardware descriptors lists is not included in this series to keep
> it simple and hopefully get it merged in v3.19. I'll post it as a separate
> series. No change to the DT bindings will be needed.
> 
> The first three patches should go through the DMA engine tree, while the last
> six patches should go through the Renesas tree. Simon, as the DT bindings have
> been merged already, I believe you can queue up the arch patches without
> waiting for the driver patches to be merged.

Thanks, I have queued up those patches: the last 6 of this series.

> Known issues are
> 
> - Untested cyclic DMA transfers. I've done my best to fix the related issues
>   from v2, but I haven't been able to test audio with the R-Car platforms (see
>   [2]). Morimoto-san, if you could help me with audio testing I'd be grateful.
> 
> - Stub system PM implementation. I'm working on this.
> 
> - Risk of conflict with Maxime's DMA engine rework series.
> 
> I believe the first two issues are not show stoppers. I can rebase the patches
> if Maxime's patches get merged first.
> 
> Changes since v2: 
>  
> - Replace several occurrences of size_t with unsigned int
> - Remove unneeded local variable initialization
> - Compute maximum transfer size at runtime
> - Typo fixes
> - Replace WARN_ON with WARN_ON_ONCE in interrupt handler
> - Validate the number of channels
> - Reset the device before enabling interrupts
> - Use DMA_SLAVE_BUSWIDTH_* constants instead of numerical values
> - Use devm_kasprintf
> - Update to the new prep_dma_cyclic API
> - Filter out channels from unrelated devices
> - Fix typo in register definition
> - Rename rcar_dmac_hw_desc to rcar_dmac_xfer_chunk
> - Ignore the deprecated dma_slave_config direction field
> - Allocate memory with GFP_NOWAIT in prep handlers
> - Split runtime and system PM
> - Move runtime PM to channel alloc/fre
> 
> Changes since v1:
> 
> - Allocate IRQ name strings dynamically
> - Only call the callback function if one is supplied
> - Don't overallocate sg list entries
> - Allocate sg list entries with GFP_KERNEL
> - Don't manage function clock manually
> - Make channel filter ignore unrelated devices
> - Document why the cyclic sg list is kcalloc'ed
> - Remove ch15 from interrupt names in DT
> - Replace CONFIG_OF with OF in Kconfig
> 
> [1] http://www.spinics.net/lists/linux-sh/msg33768.html
> [2] http://www.spinics.net/lists/linux-sh/msg36474.html
> 
> Laurent Pinchart (9):
>   dmaengine: Add 16 bytes, 32 bytes and 64 bytes bus widths
>   dmaengine: rcar-dmac: Remove duplicate sentence from DT bindings
>   dmaengine: rcar-dmac: Add Renesas R-Car Gen2 DMA Controller (DMAC)
>     driver
>   ARM: shmobile: r8a7790: Rename mmcif node to mmc
>   ARM: shmobile: r8a7791: Add MMCIF0 DT node
>   ARM: shmobile: r8a7790: Reference DMA channels in MMCIF DT nodes
>   ARM: shmobile: r8a7791: Reference DMA channels in MMCIF DT node
>   ARM: shmobile: r8a7790: Reference DMA channels in SDHI DT nodes
>   ARM: shmobile: r8a7791: Reference DMA channels in SDHI DT nodes
> 
>  .../devicetree/bindings/dma/renesas,rcar-dmac.txt  |    3 -
>  arch/arm/boot/dts/r8a7790.dtsi                     |   14 +-
>  arch/arm/boot/dts/r8a7791.dtsi                     |   17 +
>  drivers/dma/sh/Kconfig                             |    8 +
>  drivers/dma/sh/Makefile                            |    1 +
>  drivers/dma/sh/rcar-dmac.c                         | 1533 ++++++++++++++++++++
>  include/linux/dmaengine.h                          |    3 +
>  7 files changed, 1575 insertions(+), 4 deletions(-)
>  create mode 100644 drivers/dma/sh/rcar-dmac.c
> 
> -- 
> Regards,
> 
> Laurent Pinchart
> 
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