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authorPeter Ujfalusi <peter.ujfalusi@ti.com>2012-09-14 15:05:45 +0300
committerMark Brown <broonie@opensource.wolfsonmicro.com>2012-09-22 11:12:40 -0400
commit2dcdf570936168d488acf90be9b04a3d32dafce7 (patch)
treedb98bbd4b10906b6148510f6719d479e635a889f /drivers/dma
parentccffa3870a7ec2b59cf051b745220c56f423d182 (diff)
downloadlinux-2dcdf570936168d488acf90be9b04a3d32dafce7.tar.bz2
dmaengine: omap: Add support for pause/resume in cyclic dma mode
The audio stack used omap_stop_dma/omap_start_dma to pause/resume the DMA. This method has been used for years on OMAP based products. We only allow pause/resume when the DMA has been configured in cyclic mode which is used by the audio stack. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Acked-by: Vinod Koul <vinod.koul@linux.intel.com> Tested-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/omap-dma.c30
1 files changed, 25 insertions, 5 deletions
diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
index b77a40db2856..71d786973dfd 100644
--- a/drivers/dma/omap-dma.c
+++ b/drivers/dma/omap-dma.c
@@ -34,6 +34,7 @@ struct omap_chan {
struct dma_slave_config cfg;
unsigned dma_sig;
bool cyclic;
+ bool paused;
int dma_ch;
struct omap_desc *desc;
@@ -470,11 +471,14 @@ static int omap_dma_terminate_all(struct omap_chan *c)
*/
if (c->desc) {
c->desc = NULL;
- omap_stop_dma(c->dma_ch);
+ /* Avoid stopping the dma twice */
+ if (!c->paused)
+ omap_stop_dma(c->dma_ch);
}
if (c->cyclic) {
c->cyclic = false;
+ c->paused = false;
omap_dma_unlink_lch(c->dma_ch, c->dma_ch);
}
@@ -487,14 +491,30 @@ static int omap_dma_terminate_all(struct omap_chan *c)
static int omap_dma_pause(struct omap_chan *c)
{
- /* FIXME: not supported by platform private API */
- return -EINVAL;
+ /* Pause/Resume only allowed with cyclic mode */
+ if (!c->cyclic)
+ return -EINVAL;
+
+ if (!c->paused) {
+ omap_stop_dma(c->dma_ch);
+ c->paused = true;
+ }
+
+ return 0;
}
static int omap_dma_resume(struct omap_chan *c)
{
- /* FIXME: not supported by platform private API */
- return -EINVAL;
+ /* Pause/Resume only allowed with cyclic mode */
+ if (!c->cyclic)
+ return -EINVAL;
+
+ if (c->paused) {
+ omap_start_dma(c->dma_ch);
+ c->paused = false;
+ }
+
+ return 0;
}
static int omap_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,