On Tue, 2 Dec 2008 10:16:05 -0700, "Dan Williams" [off-list ref] wrote:

quoted

I think, there is a problem with your dma_request_channel() /
private_candidate() implementation: your current version only tries one
channel from a dma device list, which matched capabilities. If this
channel is not accepted by the client, you do not try other channels from
this device and just go to the next one...

Which dma driver are you using?  The dmaengine code assumes that all
channels on a device are equal.  It sounds like there are differences
between peer-channels on the device in this case.  If the driver
registers a device per channel that should give the flexibility you
want.

I'm writing a new dma driver.  My DMAC has multiple channels and only
one channel is capable for generic memcpy and other channels have
fixed role.

Does new framework allow dma driver make only one channel public?
Or should I register two dma_device for DMA_MEMCPY and DMA_SLAVE?
Could you give me some advice?

---
Atsushi Nemoto