From 49163391881af33f6aca6f3e132629974ffb0b1a Mon Sep 17 00:00:00 2001 From: Ludovic Desroches Date: Mon, 23 Nov 2015 14:09:39 +0100 Subject: [PATCH] dmaengine: at_xdmac: fix spurious flag status for mem2mem transfers commit 95da0c19d164f6df0b71a5187950f47d4b746e91 upstream. 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 Acked-by: Nicolas Ferre Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- 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 9d05d7dbcfa9..66c073fc8afc 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -864,8 +864,12 @@ 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; @@ -1042,8 +1046,12 @@ 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) @@ -1144,8 +1152,12 @@ 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) -- 2.34.1