Re: [RFC PATCH 00/13] DMA Engine support for AM33xx

From: Matt Porter
Date: Fri Sep 21 2012 - 14:20:22 EST

On Fri, Sep 21, 2012 at 08:27:07AM +0000, Hebbar, Gururaja wrote:
> On Thu, Sep 20, 2012 at 20:13:33, Porter, Matt wrote:
> > This series adds DMA Engine support for AM33xx, which uses
> > an EDMA DMAC. The EDMA DMAC has been previously supported by only
> > a private API implementation (much like the situation with OMAP
> > DMA) found on the DaVinci family of SoCs.
> >
> > There are a mind-boggling number of dependencies for this series:
> >
> > - Jon Hunter's OF DMA helpers series
> > https://patchwork.kernel.org/patch/1461061/
> > https://patchwork.kernel.org/patch/1461051/
> > - Patch to address OF DMA helpers naming issues:
> > https://patchwork.kernel.org/patch/1477921/
> > - EDMA DMA Engine wrapper driver in linux-next
> > c2dde5f8f2095d7c623ff3565c1462e190272273
> > - EDMA DMA Engine wrapper driver bug fix:
> > https://patchwork.kernel.org/patch/1474411/
> > - A huge number of patches in linux-next for AM33xx boot
> > (too numerous to list)
> >
> > The approach taken is similar to how OMAP DMA is being converted to
> > DMA Engine support. With the functional EDMA private API already
> > existing in mach-davinci/dma.c, we first move that to an ARM common
> > area so it can be shared. Adding DT and runtime PM support to the
> > private EDMA API implementation allows it to run on AM33xx. AM33xx
> > *only* boots using DT so we leverage Jon's generic DT DMA helpers to
> > register EDMA DMAC with the of_dma framework and then add support
> > for calling the dma_request_slave_channel() API to both the mmc
> > and spi drivers.
> >
> > What works? Well, with this series we now have MMC and SPI support
> > on AM33xx. The only caveat for MMC is that the mmc3 controller has
> > its events on the crossbar and is not usable right now.
> >
> > This is tested on BeagleBone with a SPI framebuffer driver and SD
> > card.
> >
> > After this series, the plan is to convert the last in-tree user
> > of the private EDMA API (davinci-pcm/mcasp) and then eliminate
> > the private EDMA API by folding its functionality into
> > drivers/dma/edma.c.
> >
> > TODO:
> > add AM33xx crossbar support to the private EDMA API
> > (any EDMA events on the crossbar are not supported)
> >
>
>
> Can you please mention the base repo you have taken as starting point.
> (repo + extra patches ...).

It's mainline 3.6-rc6 and you can see the complete set of patches
at https://github.com/ohporter/linux/tree/edma-dmaengine-am33xx-rfc-v1
after commit 5698bd757d55b1bb87edd1a9744ab09c142abfc2

> This will help us to test the code.
>
> This is because I looked at the patch 12/13 and I see that mmc
> device-node is modified. But in mainline I donât see device
> node for mmc (yet).

Oops. You'll need e62a3333ae450bcdefbe22229d7bc277ae0ef645 and
fe97304557d2c6f7d0aaf1ea028ea48ffca366a9 which I forgot to include
in this series. I'll have them in for v2.

-Matt

> > Matt Porter (13):
> > ARM: davinci: move private EDMA API to arm/common
> > ARM: edma: remove unused transfer controller handlers
> > ARM: edma: add DT and runtime PM support for AM335x
> > dmaengine: edma: enable build for AM335x
> > dma: Add TI EDMA device tree binding
> > ARM: omap: add hsmmc am33xx specific init
> > mmc: omap_hsmmc: dma_request_slave_channel() support for DT platforms
> > mmc: omap_hsmmc: limit max_segs with the EDMA DMAC
> > mmc: omap_hsmmc: add generic DMA request support to the DT binding
> > spi: omap2-mcspi: dma_request_slave_channel() support for DT
> > platforms
> > spi: omap2-mcspi: add generic DMA request support to the DT binding
> > ARM: dts: add am33xx EDMA support
> > Documentation: add schedule for removing private EDMA API
> >
> > Documentation/devicetree/bindings/dma/ti-edma.txt | 49 +
> > .../devicetree/bindings/mmc/ti-omap-hsmmc.txt | 25 +-
> > Documentation/devicetree/bindings/spi/omap-spi.txt | 27 +-
> > Documentation/feature-removal-schedule.txt | 10 +
> > arch/arm/Kconfig | 1 +
> > arch/arm/boot/dts/am33xx.dtsi | 46 +
> > arch/arm/common/Kconfig | 3 +
> > arch/arm/common/Makefile | 1 +
> > arch/arm/common/edma.c | 1779 ++++++++++++++++++++
> > arch/arm/include/asm/mach/edma.h | 267 +++
> > arch/arm/mach-davinci/Makefile | 2 +-
> > arch/arm/mach-davinci/devices.c | 3 +-
> > arch/arm/mach-davinci/dm355.c | 2 +-
> > arch/arm/mach-davinci/dm365.c | 2 +-
> > arch/arm/mach-davinci/dm644x.c | 2 +-
> > arch/arm/mach-davinci/dm646x.c | 2 +-
> > arch/arm/mach-davinci/dma.c | 1588 -----------------
> > arch/arm/mach-davinci/include/mach/asp.h | 2 +-
> > arch/arm/mach-davinci/include/mach/da8xx.h | 3 +-
> > arch/arm/mach-davinci/include/mach/edma.h | 267 ---
> > arch/arm/mach-davinci/include/mach/spi.h | 2 +-
> > arch/arm/mach-omap2/hsmmc.c | 7 +-
> > arch/arm/plat-omap/Kconfig | 1 +
> > drivers/dma/Kconfig | 2 +-
> > drivers/dma/edma.c | 2 +-
> > drivers/mmc/host/omap_hsmmc.c | 26 +-
> > drivers/spi/spi-omap2-mcspi.c | 68 +-
> > 27 files changed, 2296 insertions(+), 1893 deletions(-)
> > create mode 100644 Documentation/devicetree/bindings/dma/ti-edma.txt
> > create mode 100644 arch/arm/common/edma.c
> > create mode 100644 arch/arm/include/asm/mach/edma.h
> > delete mode 100644 arch/arm/mach-davinci/dma.c
> > delete mode 100644 arch/arm/mach-davinci/include/mach/edma.h
> >
> > --
> > 1.7.9.5
> >
> > _______________________________________________
> > Davinci-linux-open-source mailing list
> > Davinci-linux-open-source@xxxxxxxxxxxxxxxxxxxx
> > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
> >
>
>
> Regards,
> Gururaja
> _______________________________________________
> Davinci-linux-open-source mailing list
> Davinci-linux-open-source@xxxxxxxxxxxxxxxxxxxx
> http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
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