> From: Cornelia Huck [mailto:[EMAIL PROTECTED]
> Finer granularity is certainly better here, but I'm not quite sure if
> this solves our s390 problem (we don't have dma support). All those
> backends should also have a non-dma version...
In fact that is already there. Here is the form of async_memcpy for
example:
... async_memcpy( ... )
{
struct dma_chan *chan = async_tx_find_channel(depend_tx,
DMA_MEMCPY);
struct dma_device *device = chan ? chan->device : NULL;
int int_en = callback ? 1 : 0;
struct dma_async_tx_descriptor *tx = device ?
device->device_prep_dma_memcpy(chan, len,
int_en) : NULL;
if (tx) { /* run the memcpy asynchronously */
...
} else { /* run the memcpy synchronously */
...
}
}
When CONFIG_DMA_ENGINE=n async_tx_find_channel takes the form:
... async_tx_find_channel( ... )
{
return NULL;
}
So in the S390 case the entire asynchronous path will be compiled away.
--
Dan
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