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drivers: generic: dummydma: Make the Dummy DMA compatible with caching 

The semantics of a DMA driver is to transfer data to/from RAM rather
than to/from the DSP cache. As such I need to flush the cache before
and after the copy (see comments inline).

Signed-off-by: Paul Olaru <paul.olaru@nxp.com>
This commit is contained in:
Paul Olaru 2019-10-23 17:52:01 +03:00 committed by Tomasz Lauda
parent a564aa293a
commit 44c1d9217f
1 changed files with 14 additions and 0 deletions
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14
src/drivers/generic/dummy-dma.c
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@ -29,6 +29,7 @@
#include <sof/audio/component.h>
#include <sof/drivers/timer.h>
#include <sof/lib/alloc.h>
#include <sof/lib/cache.h>
#include <sof/lib/dma.h>
#include <sof/platform.h>
#include <sof/spinlock.h>
@ -93,10 +94,23 @@ static size_t dummy_dma_copy_crt_elem(struct dma_chan_pdata *pdata,
remaining_size = orig_size - pdata->elem_progress;
copy_size = MIN(remaining_size, bytes);
/* On playback, invalidate host buffer (it may lie in a cached area).
* Otherwise we could be playing stale data.
* On capture this should be safe as host.c does a writeback before
* triggering the DMA.
*/
dcache_invalidate_region((void *)rptr, copy_size);
/* Perform the copy, being careful if we overflow the elem */
ret = memcpy_s((void *)wptr, remaining_size, (void *)rptr, copy_size);
assert(!ret);
/* On capture, writeback the host buffer (it may lie in a cached area).
* On playback, also writeback because host.c does an invalidate to
* be able to use the data transferred by the DMA.
*/
dcache_writeback_region((void *)wptr, copy_size);
pdata->elem_progress += copy_size;
if (remaining_size == copy_size) {