| Message ID | 1396357575-30585-4-git-send-email-peter.ujfalusi@ti.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Vinod Koul |
| Headers | show |
On Tue, Apr 01, 2014 at 04:06:04PM +0300, Peter Ujfalusi wrote: > Pause/Resume can be used by the audio stack when the stream is paused/resumed > The edma platform code has support for this and the legacy audio stack used > this. > > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> > --- > drivers/dma/edma.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c > index 2742867fd1e6..7891378a03f0 100644 > --- a/drivers/dma/edma.c > +++ b/drivers/dma/edma.c > @@ -240,6 +240,26 @@ static int edma_slave_config(struct edma_chan *echan, > return 0; > } > > +static int edma_dma_pause(struct edma_chan *echan) > +{ > + /* Pause/Resume only allowed with cyclic mode */ > + if (!echan->edesc->cyclic) > + return -EINVAL; why this artificial restriction? The driver can do pause even for non cyclic cases too? Yes the usage is in cyclic context but why should we limit any future work on this?
On 04/11/2014 11:43 AM, Vinod Koul wrote: > On Tue, Apr 01, 2014 at 04:06:04PM +0300, Peter Ujfalusi wrote: >> Pause/Resume can be used by the audio stack when the stream is paused/resumed >> The edma platform code has support for this and the legacy audio stack used >> this. >> >> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> >> --- >> drivers/dma/edma.c | 28 ++++++++++++++++++++++++++++ >> 1 file changed, 28 insertions(+) >> >> diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c >> index 2742867fd1e6..7891378a03f0 100644 >> --- a/drivers/dma/edma.c >> +++ b/drivers/dma/edma.c >> @@ -240,6 +240,26 @@ static int edma_slave_config(struct edma_chan *echan, >> return 0; >> } >> >> +static int edma_dma_pause(struct edma_chan *echan) >> +{ >> + /* Pause/Resume only allowed with cyclic mode */ >> + if (!echan->edesc->cyclic) >> + return -EINVAL; > why this artificial restriction? The driver can do pause even for non cyclic > cases too? Yes the usage is in cyclic context but why should we limit any future > work on this? > We struggled with this, and we certainly we don't want pauses in non-cyclic EDMA... we tried doing a "pause" and it was a disaster as the events keep coming in and those can't be paused, and EDMA hardware wont queue them during the pause, it'll just generate an error interrupt storm. Thanks, -Joel -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index 2742867fd1e6..7891378a03f0 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -240,6 +240,26 @@ static int edma_slave_config(struct edma_chan *echan, return 0; } +static int edma_dma_pause(struct edma_chan *echan) +{ + /* Pause/Resume only allowed with cyclic mode */ + if (!echan->edesc->cyclic) + return -EINVAL; + + edma_pause(echan->ch_num); + return 0; +} + +static int edma_dma_resume(struct edma_chan *echan) +{ + /* Pause/Resume only allowed with cyclic mode */ + if (!echan->edesc->cyclic) + return -EINVAL; + + edma_resume(echan->ch_num); + return 0; +} + static int edma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned long arg) { @@ -255,6 +275,14 @@ static int edma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, config = (struct dma_slave_config *)arg; ret = edma_slave_config(echan, config); break; + case DMA_PAUSE: + ret = edma_dma_pause(echan); + break; + + case DMA_RESUME: + ret = edma_dma_resume(echan); + break; + default: ret = -ENOSYS; }
Pause/Resume can be used by the audio stack when the stream is paused/resumed The edma platform code has support for this and the legacy audio stack used this. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> --- drivers/dma/edma.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)