Re: [PATCH 4/7] dmaengine: at_xdmac: adapt perid for mem2mem operations
From: <hidden>
Date: 2020-09-23 05:30:47
Also in:
dmaengine, linux-devicetree, lkml
On 9/14/20 5:09 PM, Eugen Hristev wrote:
The PERID in the CC register for mem2mem operations must match an unused PERID. The PERID field is 7 bits, but the selected value is 0x3f. On later products we can have more reserved PERIDs for actual peripherals, thus this needs to be increased to maximum size. Changing the value to 0x7f, which is the maximum for 7 bits field.
Maybe it is worth to explain that for memory-to-memory transfers, PERID should be set to an unused peripheral ID, and the maximum value seems the safest. Anyway with or without this addressed, one can add: Reviewed-by: Tudor Ambarus <redacted>
quoted hunk ↗ jump to hunk
Signed-off-by: Eugen Hristev <redacted> --- drivers/dma/at_xdmac.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index fab19e00a7be..81bb90206092 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c@@ -726,7 +726,7 @@ at_xdmac_interleaved_queue_desc(struct dma_chan *chan, * match the one of another channel. If not, it could lead to spurious * flag status. */ - u32 chan_cc = AT_XDMAC_CC_PERID(0x3f) + u32 chan_cc = AT_XDMAC_CC_PERID(0x7f) | AT_XDMAC_CC_DIF(0) | AT_XDMAC_CC_SIF(0) | AT_XDMAC_CC_MBSIZE_SIXTEEN@@ -908,7 +908,7 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, * match the one of another channel. If not, it could lead to spurious * flag status. */ - u32 chan_cc = AT_XDMAC_CC_PERID(0x3f) + u32 chan_cc = AT_XDMAC_CC_PERID(0x7f) | AT_XDMAC_CC_DAM_INCREMENTED_AM | AT_XDMAC_CC_SAM_INCREMENTED_AM | AT_XDMAC_CC_DIF(0)@@ -1014,7 +1014,7 @@ static struct at_xdmac_desc *at_xdmac_memset_create_desc(struct dma_chan *chan, * match the one of another channel. If not, it could lead to spurious * flag status. */ - u32 chan_cc = AT_XDMAC_CC_PERID(0x3f) + u32 chan_cc = AT_XDMAC_CC_PERID(0x7f) | AT_XDMAC_CC_DAM_UBS_AM | AT_XDMAC_CC_SAM_INCREMENTED_AM | AT_XDMAC_CC_DIF(0)
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