Re: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx
On Monday 04 October 2010 10:36:16 ext G, Manjunath Kondaiah wrote: are going to have: DMA_ERRATA_i541_OMAP2, and DMA_ERRATA_i541_OMAP3 to For OMAP2, you should use DMA_ERRATA_IFRAME_BUFFERING since it is different type of issue. Thanks! I'll do that. -Manjunath -- Péter -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx
Peter, -Original Message- From: Peter Ujfalusi [mailto:peter.ujfal...@nokia.com] Sent: Monday, October 04, 2010 12:46 PM To: G, Manjunath Kondaiah Cc: Jarkko Nikula; Tony Lindgren; linux-omap@vger.kernel.org; Liam Girdwood Subject: Re: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx On Monday 04 October 2010 09:23:18 ext G, Manjunath Kondaiah wrote: No errata numbers numbers used with TI errata documents till omap2430. Errata numbers avaialable from omap3430 onwards. For OMAP3 the errata number is i541, but I do not know the iXYZ number for OMAP2 class. Being said that no errata numbers for omap2 class, it's ok to use omap3 errata numbers for common errata(like your patch 2/2) Thanks, we are going to use the same errata ID for OMAP2, and OMAP3, but going to use different workaround for them: OMAP2: disable buffering This issue seems to be completly different from omap3 i541. This is required to flush out fifo contents properly where as with i541, it requires DMA controller to be put in no mstandby mode before stoping DMA transfer. OMAP3: implement the workaround as it is in the errata So, as Tony suggested, I'll add the errata handling, and we If you are introducing errata handling, are you taking care of existing errata in DMA driver also? If not, it is better to go ahead current implementation. DMA hwmod patches will introduce errata handling and these changes can be rebased once it is available in mainline. are going to have: DMA_ERRATA_i541_OMAP2, and DMA_ERRATA_i541_OMAP3 to For OMAP2, you should use DMA_ERRATA_IFRAME_BUFFERING since it is different type of issue. -Manjunath -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx
On Monday 04 October 2010 09:23:18 ext G, Manjunath Kondaiah wrote: No errata numbers numbers used with TI errata documents till omap2430. Errata numbers avaialable from omap3430 onwards. For OMAP3 the errata number is i541, but I do not know the iXYZ number for OMAP2 class. Being said that no errata numbers for omap2 class, it's ok to use omap3 errata numbers for common errata(like your patch 2/2) Thanks, we are going to use the same errata ID for OMAP2, and OMAP3, but going to use different workaround for them: OMAP2: disable buffering OMAP3: implement the workaround as it is in the errata So, as Tony suggested, I'll add the errata handling, and we are going to have: DMA_ERRATA_i541_OMAP2, and DMA_ERRATA_i541_OMAP3 to differentiate the different workarounds. We can than experiment, and we might use the OMAP3 workaround for OMAP2 as well. I'll send the v4 series shortly (after testing). -- Péter -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx
On Monday 04 October 2010 08:55:46 ext G, Manjunath Kondaiah wrote: 2/2 is applicable for all omap2plus except omap4. So far 2/2 workaround is not used with TI internal trees. We experimented that also on 2420 and it seemed to help but since the lockup was unrecovable I went thinking if 2420 has also another issue what original workaround was trying to fix and buffering disable was needed there. I don't have any data for 2420. Based on your observation, it is better to disable buffering for 2420. Does the same errata number applies to OMAP2 and OMAP3 as well? For OMAP3 the errata number is i541, but I do not know the iXYZ number for OMAP2 class. Thanks, Péter -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx
-Original Message- From: Jarkko Nikula [mailto:jhnik...@gmail.com] Sent: Monday, October 04, 2010 11:13 AM To: G, Manjunath Kondaiah Cc: Peter Ujfalusi; Tony Lindgren; linux-omap@vger.kernel.org; Liam Girdwood Subject: Re: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx On Sat, 2 Oct 2010 10:12:50 +0530 G, Manjunath Kondaiah manj...@ti.com wrote: --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -1000,7 +1000,7 @@ void omap_start_dma(int lch) * This will always fail on ES1.0 */ if (cpu_is_omap24xx()) - l |= OMAP_DMA_CCR_EN; + l |= OMAP_DMA_CCR_BUFFERING_DISABLE; This issue is applicable only for 2430ES1.0(not sure about 2420) and it got fixed with later ES versions. cpu check should be replaced with: if (cpu_is_omap2420() || (cpu_is_omap2430() (omap_type() == OMAP2430_REV_ES1_0))) Ok, thanks for your info, I'll change this. How about later versions of 2430? Fixed in later versions ES2.0 and ES2.1 Should they use the workaround in Patch 2/2? 2/2 is applicable for all omap2plus except omap4. So far 2/2 workaround is not used with TI internal trees. We experimented that also on 2420 and it seemed to help but since the lockup was unrecovable I went thinking if 2420 has also another issue what original workaround was trying to fix and buffering disable was needed there. I don't have any data for 2420. Based on your observation, it is better to disable buffering for 2420. -Manjunath-- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx
-Original Message- From: Peter Ujfalusi [mailto:peter.ujfal...@nokia.com] Sent: Monday, October 04, 2010 11:45 AM To: G, Manjunath Kondaiah Cc: Jarkko Nikula; Tony Lindgren; linux-omap@vger.kernel.org; Liam Girdwood Subject: Re: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx On Monday 04 October 2010 08:55:46 ext G, Manjunath Kondaiah wrote: 2/2 is applicable for all omap2plus except omap4. So far 2/2 workaround is not used with TI internal trees. We experimented that also on 2420 and it seemed to help but since the lockup was unrecovable I went thinking if 2420 has also another issue what original workaround was trying to fix and buffering disable was needed there. I don't have any data for 2420. Based on your observation, it is better to disable buffering for 2420. Does the same errata number applies to OMAP2 and OMAP3 as well? No errata numbers numbers used with TI errata documents till omap2430. Errata numbers avaialable from omap3430 onwards. For OMAP3 the errata number is i541, but I do not know the iXYZ number for OMAP2 class. Being said that no errata numbers for omap2 class, it's ok to use omap3 errata numbers for common errata(like your patch 2/2) -Manjunath -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx
On Sat, 2 Oct 2010 10:12:50 +0530 G, Manjunath Kondaiah manj...@ti.com wrote: --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -1000,7 +1000,7 @@ void omap_start_dma(int lch) * This will always fail on ES1.0 */ if (cpu_is_omap24xx()) - l |= OMAP_DMA_CCR_EN; + l |= OMAP_DMA_CCR_BUFFERING_DISABLE; This issue is applicable only for 2430ES1.0(not sure about 2420) and it got fixed with later ES versions. cpu check should be replaced with: if (cpu_is_omap2420() || (cpu_is_omap2430() (omap_type() == OMAP2430_REV_ES1_0))) Ok, thanks for your info, I'll change this. How about later versions of 2430? Should they use the workaround in Patch 2/2? We experimented that also on 2420 and it seemed to help but since the lockup was unrecovable I went thinking if 2420 has also another issue what original workaround was trying to fix and buffering disable was needed there. -- Jarkko -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx
From: Jarkko Nikula jhnik...@gmail.com An errata workaround for omap24xx is not setting the buffering disable bit 25 what is the purpose but channel enable bit 7 instead. Background for this fix is the DMA stalling issue with ASoC omap-mcbsp driver. Peter Ujfalusi peter.ujfal...@nokia.com has found an issue in recording that the DMA stall could happen if there were a buffer overrun detected by ALSA and the DMA was stopped and restarted due that. This problem is known to occur on both OMAP2420 and OMAP3. It can recover on OMAP3 after dma free, dma request and reconfiguration cycle. However, on OMAP2420 it seems that only way to recover is a reset. Problem was not visible before the commit c12abc0. That commit changed that the McBSP transmitter/receiver is released from reset only when needed. That is, only enabled McBSP transmitter without transmission was able to prevent this DMA stall problem in receiving side and underlying problem did not show up until now. McBSP transmitter itself seems to no be reason since DMA stall does not recover by enabling the transmission after stall. Debugging showed that there were a DMA write active during DMA stop time and it never completed even when restarting the DMA. Experimenting showed that the DMA buffering disable bit could be used to avoid stalling when using source synchronized transfers. However that could have performance hit and OMAP3 TRM states that buffering disable is not allowed for destination synchronized transfers so subsequent patch will implement a method to complete DMA writes when stopping. This patch is based on assumtion that complete lock-up on OMAP2420 is different but related problem. I don't have access to OMAP2420 errata but I believe this old workaround here is put for a reason but unfortunately a wrong bit was typed and problem showed up only now. Signed-off-by: Jarkko Nikula jhnik...@gmail.com Signed-off-by: Peter Ujfalusi peter.ujfal...@nokia.com --- arch/arm/plat-omap/dma.c |2 +- arch/arm/plat-omap/include/plat/dma.h |1 + 2 files changed, 2 insertions(+), 1 deletions(-) diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c index ec7eddf..7115884 100644 --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -1000,7 +1000,7 @@ void omap_start_dma(int lch) * This will always fail on ES1.0 */ if (cpu_is_omap24xx()) - l |= OMAP_DMA_CCR_EN; + l |= OMAP_DMA_CCR_BUFFERING_DISABLE; l |= OMAP_DMA_CCR_EN; dma_write(l, CCR(lch)); diff --git a/arch/arm/plat-omap/include/plat/dma.h b/arch/arm/plat-omap/include/plat/dma.h index af3a039..776ba44 100644 --- a/arch/arm/plat-omap/include/plat/dma.h +++ b/arch/arm/plat-omap/include/plat/dma.h @@ -335,6 +335,7 @@ #define OMAP2_DMA_MISALIGNED_ERR_IRQ (1 11) #define OMAP_DMA_CCR_EN(1 7) +#define OMAP_DMA_CCR_BUFFERING_DISABLE (1 25) #define OMAP_DMA_DATA_TYPE_S8 0x00 #define OMAP_DMA_DATA_TYPE_S16 0x01 -- 1.7.3 -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx
Peter, -Original Message- From: linux-omap-ow...@vger.kernel.org [mailto:linux-omap-ow...@vger.kernel.org] On Behalf Of Peter Ujfalusi Sent: Friday, October 01, 2010 6:06 PM To: Tony Lindgren Cc: linux-omap@vger.kernel.org; Jarkko Nikula; Liam Girdwood Subject: [PATCH v3 1/2] omap: dma: Fix buffering disable bit setting for omap24xx From: Jarkko Nikula jhnik...@gmail.com An errata workaround for omap24xx is not setting the buffering disable bit 25 what is the purpose but channel enable bit 7 instead. Background for this fix is the DMA stalling issue with ASoC omap-mcbsp driver. Peter Ujfalusi peter.ujfal...@nokia.com has found an issue in recording that the DMA stall could happen if there were a buffer overrun detected by ALSA and the DMA was stopped and restarted due that. This problem is known to occur on both OMAP2420 and OMAP3. It can recover on OMAP3 after dma free, dma request and reconfiguration cycle. However, on OMAP2420 it seems that only way to recover is a reset. Problem was not visible before the commit c12abc0. That commit changed that the McBSP transmitter/receiver is released from reset only when needed. That is, only enabled McBSP transmitter without transmission was able to prevent this DMA stall problem in receiving side and underlying problem did not show up until now. McBSP transmitter itself seems to no be reason since DMA stall does not recover by enabling the transmission after stall. Debugging showed that there were a DMA write active during DMA stop time and it never completed even when restarting the DMA. Experimenting showed that the DMA buffering disable bit could be used to avoid stalling when using source synchronized transfers. However that could have performance hit and OMAP3 TRM states that buffering disable is not allowed for destination synchronized transfers so subsequent patch will implement a method to complete DMA writes when stopping. This patch is based on assumtion that complete lock-up on OMAP2420 is different but related problem. I don't have access to OMAP2420 errata but I believe this old workaround here is put for a reason but unfortunately a wrong bit was typed and problem showed up only now. Signed-off-by: Jarkko Nikula jhnik...@gmail.com Signed-off-by: Peter Ujfalusi peter.ujfal...@nokia.com --- arch/arm/plat-omap/dma.c |2 +- arch/arm/plat-omap/include/plat/dma.h |1 + 2 files changed, 2 insertions(+), 1 deletions(-) diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c index ec7eddf..7115884 100644 --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -1000,7 +1000,7 @@ void omap_start_dma(int lch) * This will always fail on ES1.0 */ if (cpu_is_omap24xx()) - l |= OMAP_DMA_CCR_EN; + l |= OMAP_DMA_CCR_BUFFERING_DISABLE; This issue is applicable only for 2430ES1.0(not sure about 2420) and it got fixed with later ES versions. cpu check should be replaced with: if (cpu_is_omap2420() || (cpu_is_omap2430() (omap_type() == OMAP2430_REV_ES1_0))) -Manjunath -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
