| Message ID | 1395208550-1603-1-git-send-email-nsekhar@ti.com |
|---|---|
| State | Accepted |
| Commit | 5fc68a6cad658e45dca3e0a6607df3a8e5df4ef9 |
| Headers | show |
Vinod, On Wednesday 19 March 2014 11:25 AM, Sekhar Nori wrote: > The code to handle any length SG lists calls edma_resume() > even before edma_start() is called. This is incorrect > because edma_resume() enables edma events on the channel > after which CPU (in edma_start) cannot clear posted > events by writing to ECR (per the EDMA user's guide). > > Because of this EDMA transfers fail to start if due > to some reason there is a pending EDMA event registered > even before EDMA transfers are started. This can happen if > an EDMA event is a byproduct of device initialization. > > Fix this by calling edma_resume() only if it is not the > first batch of MAX_NR_SG elements. > > Without this patch, MMC/SD fails to function on DA850 EVM > with DMA. The behaviour is triggered by specific IP and > this can explain why the issue was not reported before > (example with MMC/SD on AM335x). > > Tested on DA850 EVM and AM335x EVM-SK using MMC/SD card. > > Cc: stable@vger.kernel.org # v3.12.x+ > Cc: Joel Fernandes <joelf@ti.com> > Acked-by: Joel Fernandes <joelf@ti.com> > Tested-by: Jon Ringle <jringle@gridpoint.com> > Tested-by: Alexander Holler <holler@ahsoftware.de> > Reported-by: Jon Ringle <jringle@gridpoint.com> > Signed-off-by: Sekhar Nori <nsekhar@ti.com> Looks like this patch is not in mainline still? Thanks, Sekhar -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Apr 14, 2014 at 02:01:11PM +0530, Sekhar Nori wrote: > Vinod, > > On Wednesday 19 March 2014 11:25 AM, Sekhar Nori wrote: > > The code to handle any length SG lists calls edma_resume() > > even before edma_start() is called. This is incorrect > > because edma_resume() enables edma events on the channel > > after which CPU (in edma_start) cannot clear posted > > events by writing to ECR (per the EDMA user's guide). > > > > Because of this EDMA transfers fail to start if due > > to some reason there is a pending EDMA event registered > > even before EDMA transfers are started. This can happen if > > an EDMA event is a byproduct of device initialization. > > > > Fix this by calling edma_resume() only if it is not the > > first batch of MAX_NR_SG elements. > > > > Without this patch, MMC/SD fails to function on DA850 EVM > > with DMA. The behaviour is triggered by specific IP and > > this can explain why the issue was not reported before > > (example with MMC/SD on AM335x). > > > > Tested on DA850 EVM and AM335x EVM-SK using MMC/SD card. > > > > Cc: stable@vger.kernel.org # v3.12.x+ > > Cc: Joel Fernandes <joelf@ti.com> > > Acked-by: Joel Fernandes <joelf@ti.com> > > Tested-by: Jon Ringle <jringle@gridpoint.com> > > Tested-by: Alexander Holler <holler@ahsoftware.de> > > Reported-by: Jon Ringle <jringle@gridpoint.com> > > Signed-off-by: Sekhar Nori <nsekhar@ti.com> > > Looks like this patch is not in mainline still? Sorry looks like I have missed sending the email. I had applied it last week and today rebased after rc1. It would be part of rc2...
On Monday 14 April 2014 02:27 PM, Vinod Koul wrote: > On Mon, Apr 14, 2014 at 02:01:11PM +0530, Sekhar Nori wrote: >> Vinod, >> >> On Wednesday 19 March 2014 11:25 AM, Sekhar Nori wrote: >>> The code to handle any length SG lists calls edma_resume() >>> even before edma_start() is called. This is incorrect >>> because edma_resume() enables edma events on the channel >>> after which CPU (in edma_start) cannot clear posted >>> events by writing to ECR (per the EDMA user's guide). >>> >>> Because of this EDMA transfers fail to start if due >>> to some reason there is a pending EDMA event registered >>> even before EDMA transfers are started. This can happen if >>> an EDMA event is a byproduct of device initialization. >>> >>> Fix this by calling edma_resume() only if it is not the >>> first batch of MAX_NR_SG elements. >>> >>> Without this patch, MMC/SD fails to function on DA850 EVM >>> with DMA. The behaviour is triggered by specific IP and >>> this can explain why the issue was not reported before >>> (example with MMC/SD on AM335x). >>> >>> Tested on DA850 EVM and AM335x EVM-SK using MMC/SD card. >>> >>> Cc: stable@vger.kernel.org # v3.12.x+ >>> Cc: Joel Fernandes <joelf@ti.com> >>> Acked-by: Joel Fernandes <joelf@ti.com> >>> Tested-by: Jon Ringle <jringle@gridpoint.com> >>> Tested-by: Alexander Holler <holler@ahsoftware.de> >>> Reported-by: Jon Ringle <jringle@gridpoint.com> >>> Signed-off-by: Sekhar Nori <nsekhar@ti.com> >> >> Looks like this patch is not in mainline still? > > Sorry looks like I have missed sending the email. I had applied it last week and > today rebased after rc1. It would be part of rc2... Thank you! Regards, Sekhar -- To unsubscribe from this list: send the line "unsubscribe linux-omap" 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 cd8da45..bf5ad0f 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -182,11 +182,13 @@ static void edma_execute(struct edma_chan *echan) echan->ecc->dummy_slot); } - edma_resume(echan->ch_num); - if (edesc->processed <= MAX_NR_SG) { dev_dbg(dev, "first transfer starting %d\n", echan->ch_num); edma_start(echan->ch_num); + } else { + dev_dbg(dev, "chan: %d: completed %d elements, resuming\n", + echan->ch_num, edesc->processed); + edma_resume(echan->ch_num); } /*