Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1275322
| From | Ludovic Desroches <ludovic.desroches@atmel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 2/2] dmaengine: at_xdmac: fix spurious flag status for mem2mem transfers |
| Date | 2015-11-23 14:20 +0100 |
| Message-ID | <qxZce-2dc-11@gated-at.bofh.it> (permalink) |
| References | <qxZ2z-29g-37@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
When setting the channel configuration register, the perid field is not set to 0 since it is useless for mem2mem transfers. Unfortunately, a device has 0 as perid. It could cause spurious flags status because the controller could mix some events from the two channels. For that reason, use the highest perid value for mem2mem transfers since it doesn't match the perid of other devices. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> --- drivers/dma/at_xdmac.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index d09277f..b90e62f 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -863,8 +863,12 @@ at_xdmac_interleaved_queue_desc(struct dma_chan *chan, * access. Hopefully we can access DDR through both ports (at least on * SAMA5D4x), so we can use the same interface for source and dest, * that solves the fact we don't know the direction. + * ERRATA: Even if useless for memory transfers, the PERID has to not + * match the one of another channel. If not, it could lead to spurious + * flag status. */ - u32 chan_cc = AT_XDMAC_CC_DIF(0) + u32 chan_cc = AT_XDMAC_CC_PERID(0x3f) + | AT_XDMAC_CC_DIF(0) | AT_XDMAC_CC_SIF(0) | AT_XDMAC_CC_MBSIZE_SIXTEEN | AT_XDMAC_CC_TYPE_MEM_TRAN; @@ -1039,8 +1043,12 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, * access DDR through both ports (at least on SAMA5D4x), so we can use * the same interface for source and dest, that solves the fact we * don't know the direction. + * ERRATA: Even if useless for memory transfers, the PERID has to not + * match the one of another channel. If not, it could lead to spurious + * flag status. */ - u32 chan_cc = AT_XDMAC_CC_DAM_INCREMENTED_AM + u32 chan_cc = AT_XDMAC_CC_PERID(0x3f) + | AT_XDMAC_CC_DAM_INCREMENTED_AM | AT_XDMAC_CC_SAM_INCREMENTED_AM | AT_XDMAC_CC_DIF(0) | AT_XDMAC_CC_SIF(0) @@ -1140,8 +1148,12 @@ static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan, * access. Hopefully we can access DDR through both ports (at least on * SAMA5D4x), so we can use the same interface for source and dest, * that solves the fact we don't know the direction. + * ERRATA: Even if useless for memory transfers, the PERID has to not + * match the one of another channel. If not, it could lead to spurious + * flag status. */ - u32 chan_cc = AT_XDMAC_CC_DAM_UBS_AM + u32 chan_cc = AT_XDMAC_CC_PERID(0x3f) + | AT_XDMAC_CC_DAM_UBS_AM | AT_XDMAC_CC_SAM_INCREMENTED_AM | AT_XDMAC_CC_DIF(0) | AT_XDMAC_CC_SIF(0) -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 1/2] dmaengine: at_xdmac: fix macro typo Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-23 14:10 +0100
[PATCH 2/2] dmaengine: at_xdmac: fix spurious flag status for mem2mem transfers Ludovic Desroches <ludovic.desroches@atmel.com> - 2015-11-23 14:20 +0100
Re: [PATCH 2/2] dmaengine: at_xdmac: fix spurious flag status for mem2mem transfers Nicolas Ferre <nicolas.ferre@atmel.com> - 2015-11-23 15:50 +0100
Re: [PATCH 1/2] dmaengine: at_xdmac: fix macro typo Nicolas Ferre <nicolas.ferre@atmel.com> - 2015-11-23 15:50 +0100
csiph-web