Re: [PATCH v3 02/15] dmaengine: omap: Add support for pause/resume in cyclic dma mode
On Mon, Sep 17, 2012 at 08:43:57AM +0530, Vinod Koul wrote: > On Fri, 2012-09-14 at 15:05 +0300, Peter Ujfalusi wrote: > > - /* FIXME: not supported by platform private API */ > > - return -EINVAL; > > + /* Pause/Resume only allowed with cyclic mode */ > > + if (!c->cyclic) > > + return -EINVAL; > This is not a dma restriction right? This is needed because this is not a real "pause" - it is a stop, which causes the contents of the DMA engine's FIFOs to be discarded - which means a subsequent resume will loose data. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v3 02/15] dmaengine: omap: Add support for pause/resume in cyclic dma mode
On Mon, Sep 17, 2012 at 08:43:57AM +0530, Vinod Koul wrote: On Fri, 2012-09-14 at 15:05 +0300, Peter Ujfalusi wrote: - /* FIXME: not supported by platform private API */ - return -EINVAL; + /* Pause/Resume only allowed with cyclic mode */ + if (!c-cyclic) + return -EINVAL; This is not a dma restriction right? This is needed because this is not a real pause - it is a stop, which causes the contents of the DMA engine's FIFOs to be discarded - which means a subsequent resume will loose data. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v3 02/15] dmaengine: omap: Add support for pause/resume in cyclic dma mode
On Fri, 2012-09-14 at 15:05 +0300, Peter Ujfalusi wrote: > 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 > CC: Russell King > --- Acked-by: Vinod Koul -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v3 02/15] dmaengine: omap: Add support for pause/resume in cyclic dma mode
Hi Vinod, On 09/17/2012 06:13 AM, Vinod Koul wrote: > On Fri, 2012-09-14 at 15:05 +0300, Peter Ujfalusi wrote: >> - /* FIXME: not supported by platform private API */ >> - return -EINVAL; >> + /* Pause/Resume only allowed with cyclic mode */ >> + if (!c->cyclic) >> + return -EINVAL; > This is not a dma restriction right? The pause/resume operation has been only used by audio. This might work with non cyclic modes as well but it has never been used/tested so to be safe I have added this restriction. -- Péter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v3 02/15] dmaengine: omap: Add support for pause/resume in cyclic dma mode
Hi Vinod, On 09/17/2012 06:13 AM, Vinod Koul wrote: On Fri, 2012-09-14 at 15:05 +0300, Peter Ujfalusi wrote: - /* FIXME: not supported by platform private API */ - return -EINVAL; + /* Pause/Resume only allowed with cyclic mode */ + if (!c-cyclic) + return -EINVAL; This is not a dma restriction right? The pause/resume operation has been only used by audio. This might work with non cyclic modes as well but it has never been used/tested so to be safe I have added this restriction. -- Péter -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v3 02/15] dmaengine: omap: Add support for pause/resume in cyclic dma mode
On Fri, 2012-09-14 at 15:05 +0300, Peter Ujfalusi wrote: 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.ujfal...@ti.com CC: Russell King rmk+ker...@arm.linux.org.uk --- Acked-by: Vinod Koul vinod.k...@linux.intel.com -- ~Vinod -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v3 02/15] dmaengine: omap: Add support for pause/resume in cyclic dma mode
On Fri, 2012-09-14 at 15:05 +0300, Peter Ujfalusi wrote: > - /* FIXME: not supported by platform private API */ > - return -EINVAL; > + /* Pause/Resume only allowed with cyclic mode */ > + if (!c->cyclic) > + return -EINVAL; This is not a dma restriction right? -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v3 02/15] dmaengine: omap: Add support for pause/resume in cyclic dma mode
On Fri, 2012-09-14 at 15:05 +0300, Peter Ujfalusi wrote: - /* FIXME: not supported by platform private API */ - return -EINVAL; + /* Pause/Resume only allowed with cyclic mode */ + if (!c-cyclic) + return -EINVAL; This is not a dma restriction right? -- ~Vinod -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH v3 02/15] 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
CC: Russell King
---
drivers/dma/omap-dma.c | 30 +-
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
index b77a40d..71d7869 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,
--
1.7.12
--
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[PATCH v3 02/15] 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.ujfal...@ti.com
CC: Russell King rmk+ker...@arm.linux.org.uk
---
drivers/dma/omap-dma.c | 30 +-
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
index b77a40d..71d7869 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,
--
1.7.12
--
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