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authorManuel Lauss <manuel.lauss@gmail.com>2023-05-11 18:30:10 +0300
committerThomas Bogendoerfer <tsbogend@alpha.franken.de>2023-05-23 12:00:02 +0300
commit2d645604f69f3a772d58ead702f9a8e84ab2b342 (patch)
treefb4c28a89ea1ce48b84ad6c690c0bb052b05c203 /arch/mips/alchemy
parentf2041708dee30a3425f680265c337acd28293782 (diff)
downloadlinux-2d645604f69f3a772d58ead702f9a8e84ab2b342.tar.xz
MIPS: Alchemy: fix dbdma2
Various fixes for the Au1200/Au1550/Au1300 DBDMA2 code: - skip cache invalidation if chip has working coherency circuitry. - invalidate KSEG0-portion of the (physical) data address. - force the dma channel doorbell write out to bus immediately with a sync. Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Diffstat (limited to 'arch/mips/alchemy')
-rw-r--r--arch/mips/alchemy/common/dbdma.c27
1 files changed, 15 insertions, 12 deletions
diff --git a/arch/mips/alchemy/common/dbdma.c b/arch/mips/alchemy/common/dbdma.c
index 5ab043000409..6a3c890f7bbf 100644
--- a/arch/mips/alchemy/common/dbdma.c
+++ b/arch/mips/alchemy/common/dbdma.c
@@ -30,6 +30,7 @@
*
*/
+#include <linux/dma-map-ops.h> /* for dma_default_coherent */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
@@ -623,17 +624,18 @@ u32 au1xxx_dbdma_put_source(u32 chanid, dma_addr_t buf, int nbytes, u32 flags)
dp->dscr_cmd0 &= ~DSCR_CMD0_IE;
/*
- * There is an errata on the Au1200/Au1550 parts that could result
- * in "stale" data being DMA'ed. It has to do with the snoop logic on
- * the cache eviction buffer. DMA_NONCOHERENT is on by default for
- * these parts. If it is fixed in the future, these dma_cache_inv will
- * just be nothing more than empty macros. See io.h.
+ * There is an erratum on certain Au1200/Au1550 revisions that could
+ * result in "stale" data being DMA'ed. It has to do with the snoop
+ * logic on the cache eviction buffer. dma_default_coherent is set
+ * to false on these parts.
*/
- dma_cache_wback_inv((unsigned long)buf, nbytes);
+ if (!dma_default_coherent)
+ dma_cache_wback_inv(KSEG0ADDR(buf), nbytes);
dp->dscr_cmd0 |= DSCR_CMD0_V; /* Let it rip */
wmb(); /* drain writebuffer */
dma_cache_wback_inv((unsigned long)dp, sizeof(*dp));
ctp->chan_ptr->ddma_dbell = 0;
+ wmb(); /* force doorbell write out to dma engine */
/* Get next descriptor pointer. */
ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));
@@ -685,17 +687,18 @@ u32 au1xxx_dbdma_put_dest(u32 chanid, dma_addr_t buf, int nbytes, u32 flags)
dp->dscr_source1, dp->dscr_dest0, dp->dscr_dest1);
#endif
/*
- * There is an errata on the Au1200/Au1550 parts that could result in
- * "stale" data being DMA'ed. It has to do with the snoop logic on the
- * cache eviction buffer. DMA_NONCOHERENT is on by default for these
- * parts. If it is fixed in the future, these dma_cache_inv will just
- * be nothing more than empty macros. See io.h.
+ * There is an erratum on certain Au1200/Au1550 revisions that could
+ * result in "stale" data being DMA'ed. It has to do with the snoop
+ * logic on the cache eviction buffer. dma_default_coherent is set
+ * to false on these parts.
*/
- dma_cache_inv((unsigned long)buf, nbytes);
+ if (!dma_default_coherent)
+ dma_cache_inv(KSEG0ADDR(buf), nbytes);
dp->dscr_cmd0 |= DSCR_CMD0_V; /* Let it rip */
wmb(); /* drain writebuffer */
dma_cache_wback_inv((unsigned long)dp, sizeof(*dp));
ctp->chan_ptr->ddma_dbell = 0;
+ wmb(); /* force doorbell write out to dma engine */
/* Get next descriptor pointer. */
ctp->put_ptr = phys_to_virt(DSCR_GET_NXTPTR(dp->dscr_nxtptr));