[PATCH v2 2/2] Crypto: Talitos: Support for Async_tx XOR offload

Kumar Gala galak at kernel.crashing.org
Fri Dec 18 05:45:01 EST 2009

On Dec 17, 2009, at 11:44 AM, Dan Williams wrote:

> Ira W. Snyder wrote:
>> Yes, I have used the device_prep_dma_interrupt() functionality quite a
>> while back. However, I found it to be pretty much useless.
> The specific case it is needed for Talitos/raid is a channel switch interrupt.  The interrupt causes the cleanup operation to be run which will kick off any pending dependent operations on the xor channel.  In the raid case we only have callbacks at the end of a chain, so we need the interrupt to kick the engine in an operation chain like xor->copy->xor->callback.

Ok, I'm still confused as to how the DMA interrupt interacts with the Talitos/raid side of things.  The should be completely independent (separate interrupts, separate IP blocks).

- k

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