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>

diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index 80d35f760b4a4a51e60c355a84d538bac3892a4d..599c218dc8a73172dd4bd4a058fc8f95a73f982f 100644 (file)
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -253,8 +253,11 @@ 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;