kernel@xxxxxxxxxxxxxxxx writes: > From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> > > The original patch contained 3 dma channels that were masked out. > > These - as far as research and discussions show - are a > artefacts remaining from the downstream legacy dma-api. > > Right now down-stream still includes a legacy api used only > in a single (downstream only) driver (bcm2708_fb) that requires > 2D DMA for speedup (DMA-channel 0). > Formerly the sd-card support driver also was using this legacy > api (DMA-channel 2), but since has been moved over to use > dmaengine directly. > > The DMA-channel 3 is already masked out in the devicetree in > the default property "brcm,dma-channel-mask = <0x7f35>;" Delayed the rest of the review, because I went digging around in the firmware, and missed the ifdef mess in it that produced 0x7f35. As far as I can tell, though, we should be using just that value to control which channels we expose (other than the shared-irq issue). If the firmware wants to use a different set of channels some day, they'll have to edit our DT. Reviewed-by: Eric Anholt <eric@xxxxxxxxxx>
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