[ 71/76] ASoC: fsi: dont reschedule DMA from an atomic context

Greg Kroah-Hartman
2012-10-19T02:52:31Z

From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>

commit 57451e437796548d658d03c2c4aab659eafcd799 upstream.

shdma doesn't support transfer re-scheduling or triggering from callbacks
or from atomic context. The fsi driver issues DMA transfers from a tasklet
context, which is a bug. To fix it convert tasklet to a work.

Reported-by: Do Q.Thang <dq-thang@jinso.co.jp>
Tested-by: Do Q.Thang <dq-thang@jinso.co.jp>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/soc/sh/fsi.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

--- a/sound/soc/sh/fsi.c
+++ b/sound/soc/sh/fsi.c
@@ -20,6 +20,7 @@
#include <linux/sh_dma.h>
#include <linux/slab.h>
#include <linux/module.h>
+#include <linux/workqueue.h>
#include <sound/soc.h>
#include <sound/sh_fsi.h>

@@ -223,7 +224,7 @@ struct fsi_stream {
*/
struct dma_chan *chan;
struct sh_dmae_slave slave; /* see fsi_handler_init() */
- struct tasklet_struct tasklet;
+ struct work_struct work;
dma_addr_t dma;
};

@@ -1085,9 +1086,9 @@ static void fsi_dma_complete(void *data)
snd_pcm_period_elapsed(io->substream);
}

-static void fsi_dma_do_tasklet(unsigned long data)
+static void fsi_dma_do_work(struct work_struct *work)
{
- struct fsi_stream *io = (struct fsi_stream *)data;
+ struct fsi_stream *io = container_of(work, struct fsi_stream, work);
struct fsi_priv *fsi = fsi_stream_to_priv(io);
struct snd_soc_dai *dai;
struct dma_async_tx_descriptor *desc;
@@ -1129,7 +1130,7 @@ static void fsi_dma_do_tasklet(unsigned
* FIXME
*
* In DMAEngine case, codec and FSI cannot be started simultaneously
- * since FSI is using tasklet.
+ * since FSI is using the scheduler work queue.
* Therefore, in capture case, probably FSI FIFO will have got
* overflow error in this point.
* in that case, DMA cannot start transfer until error was cleared.
@@ -1153,7 +1154,7 @@ static bool fsi_dma_filter(struct dma_ch

static int fsi_dma_transfer(struct fsi_priv *fsi, struct fsi_stream *io)
{
- tasklet_schedule(&io->tasklet);
+ schedule_work(&io->work);

return 0;
}
@@ -1195,14 +1196,14 @@ static int fsi_dma_probe(struct fsi_priv
return fsi_stream_probe(fsi, dev);
}

- tasklet_init(&io->tasklet, fsi_dma_do_tasklet, (unsigned long)io);
+ INIT_WORK(&io->work, fsi_dma_do_work);

return 0;
}

static int fsi_dma_remove(struct fsi_priv *fsi, struct fsi_stream *io)
{
- tasklet_kill(&io->tasklet);
+ cancel_work_sync(&io->work);

fsi_stream_stop(fsi, io);