dmaengine: at_xdmac: fix spurious flag status for mem2mem transfers

[firefly-linux-kernel-4.4.55.git] / drivers / dma / at_xdmac.c

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index 9d05d7dbcfa94fc83f2634e4b5eddb6162f905a2..66c073fc8afc6e18809b9e429f783781a199f46c 100644 (file)
--- 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)