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MIPS: Alchemy: fix dbdma2

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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>
This commit is contained in:
Manuel Lauss 2023-05-11 17:30:10 +02:00 committed by Thomas Bogendoerfer
parent f2041708de
commit 2d645604f6
1 changed files with 15 additions and 12 deletions
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27
arch/mips/alchemy/common/dbdma.c
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@ -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));