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>

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,