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authorMatthias Reichl <hias@horus.com>2017-02-20 20:01:16 +0100
committerVinod Koul <vinod.koul@intel.com>2017-03-06 08:49:11 +0530
commit2201ac6129fa162ac24da089a034bb0971648ebb (patch)
tree8be9bbc08e1a13278e20901442bc3e8a1366af2d /drivers/dma
parentc1ae3cfa0e89fa1a7ecc4c99031f5e9ae99d9201 (diff)
downloadop-kernel-dev-2201ac6129fa162ac24da089a034bb0971648ebb.zip
op-kernel-dev-2201ac6129fa162ac24da089a034bb0971648ebb.tar.gz
dmaengine: bcm2835: Fix cyclic DMA period splitting
The code responsible for splitting periods into chunks that can be handled by the DMA controller missed to update total_len, the number of bytes processed in the current period, when there are more chunks to follow. Therefore total_len was stuck at 0 and the code didn't work at all. This resulted in a wrong control block layout and audio issues because the cyclic DMA callback wasn't executing on period boundaries. Fix this by adding the missing total_len update. Signed-off-by: Matthias Reichl <hias@horus.com> Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Tested-by: Clive Messer <clive.messer@digitaldreamtime.co.uk> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/bcm2835-dma.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index e18dc59..6204cc3 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -251,8 +251,11 @@ static void bcm2835_dma_create_cb_set_length(
*/
/* have we filled in period_length yet? */
- if (*total_len + control_block->length < period_len)
+ if (*total_len + control_block->length < period_len) {
+ /* update number of bytes in this period so far */
+ *total_len += control_block->length;
return;
+ }
/* calculate the length that remains to reach period_length */
control_block->length = period_len - *total_len;
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