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dmaengine: bcm2835: Fix cyclic DMA period splitting

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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>
This commit is contained in:
Matthias Reichl
2016-06-07 19:37:10 +02:00
committed by popcornmix
parent 6fb261eff6
commit 574e4b6da1
1 changed files with 4 additions and 1 deletions
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5
drivers/dma/bcm2835-dma.c
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@@ -252,8 +252,11 @@ 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;