[PATCH 0/3] dmaengine: bcm2835: support dma channel 11 to 14
vinod.koul at intel.com
Tue Apr 5 10:03:37 PDT 2016
On Thu, Mar 17, 2016 at 03:24:30PM +0000, kernel at martin.sperl.org wrote:
> From: Martin Sperl <kernel at martin.sperl.org>
> Right now the dma engine officially supports dma channel 11 and 12.
> But the use of dma channel 12 immediately stalls the system.
> The reason is that the interrupt assigned right now to dma channel 11
> is actually a shared interrupt for dma channels 11 to 12.
> So whenever the dma channel 12, 13 or 14 is used, it triggers the interrupt
> for dma 11 which only clears the interrupt flag for dma channel 11.
> This results in the interrupt 11 is triggered all the time.
> On top the requesting dma channel12 (and the corresponding irq) triggers
> an immeditate stall of the system, because for the 12th interrupt
> any dma channel will trigger also this interrupt - even if the dma channel
> is controlled by the firmware.
> As the description in the default device-tree is (for the above reasons)
> wrong a new means had to get devised that allows correct representation
> of the mapping between interrupts and dma channels.
> For this the existing (but unused) device-tree property "interrupt-names"
> is used to define the mapping.
This looks fine by me, need an ACK on ARM patch before this can be applied.
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