Re: [PATCH 2/2] acpi-dma: Add support for "dma-names" device property
From: Rafael J. Wysocki
Date: Thu Sep 24 2015 - 20:01:56 EST
On Thursday, September 24, 2015 09:05:28 PM Vinod Koul wrote:
> On Mon, Sep 14, 2015 at 05:37:36PM +0300, Mika Westerberg wrote:
> > The current implementation hard codes the two supported channels so that
> > "tx" is always 0 and "rx" is always 1. This is because there has been no
> > suitable way in ACPI to name resources.
> >
> > With _DSD device properties we can finally do this:
> >
> > Device (SPI1) {
> > Name (_CRS, ResourceTemplate () {
> > ...
> > FixedDMA (0x0000, 0x0000, Width32bit)
> > FixedDMA (0x0001, 0x0001, Width32bit)
> > })
> >
> > Name (_DSD, Package () {
> > ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
> > Package () {
> > Package () {"dma-names", Package () {"tx", "rx"}}
> > },
> > })
> > }
> >
> > The names "tx" and "rx" now provide index of the FixedDMA resource in
> > question.
> >
> > Modify acpi_dma_request_slave_chan_by_name() so that it looks for
> > "dma-names" property first and only then fall back using hardcoded indices.
> >
> > The DT "dma-names" binding that we reuse for ACPI is documented in
> > Documentation/devicetree/bindings/dma/dma.txt.
>
> Acked-by: Vinod Koul <vinod.koul@xxxxxxxxx>
>
> This is actually good and will help a lot.
Thanks!
Added [1/2] and this one to my device-properties branch.
Thanks,
Rafael
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