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dmaengine: virt-dma: Add synchronization helper function 

Add a synchronize helper function for the virt-dma library. The function
makes sure that any scheduled descriptor complete callbacks have finished
running before the function returns.

This needs to be called by drivers using virt-dma in their
device_synchronize() callback. Depending on the driver additional
operations might be necessary in addition to calling vchan_synchronize() to
ensure proper synchronization.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Lars-Peter Clausen 2015-10-20 11:46:29 +02:00 committed by Vinod Koul
parent b36f09c3c4
commit 2ed086296e
1 changed files with 13 additions and 0 deletions
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13
drivers/dma/virt-dma.h
View File

@ -151,4 +151,17 @@ static inline void vchan_free_chan_resources(struct virt_dma_chan *vc)
vchan_dma_desc_free_list(vc, &head);
}
/**
* vchan_synchronize() - synchronize callback execution to the current context
* @vc: virtual channel to synchronize
*
* Makes sure that all scheduled or active callbacks have finished running. For
* proper operation the caller has to ensure that no new callbacks are scheduled
* after the invocation of this function started.
*/
static inline void vchan_synchronize(struct virt_dma_chan *vc)
{
tasklet_kill(&vc->task);
}
#endif