bcm2835: DMA Channels and interrupts
kernel at martin.sperl.org
Mon Sep 14 07:50:56 PDT 2015
During a discussion with regards to the downstream kernel (and a bug found there)
we came to realize that the the DMA channels 11 to 14 share a common interrupt line.
On top it seems (by looking at the broadcom Graphics driver stack header-files) as if
DMA15 does not even have a shared interrupt - I guess it only triggers with the
“catch all" DMA irq <1 28>.
So the question is how we want to handle this situation in the upstream kernel?
Should we just use the shared interrupt (<1 28>) and write our mini-interrupt-controller
to get all DMA channels handled correctly?
Or should we use shared IRQs and ignore DMA15 (which is not in the channel-mask anyway)?
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