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.
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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