diff options
| author | Sugar Zhang <sugar.zhang@rock-chips.com> | 2020-06-29 22:05:43 +0800 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2020-07-15 11:25:11 +0530 |
| commit | 3e7f0bd872087bf4653eeee9a83050f91baae907 (patch) | |
| tree | 628c22c042f1b88acb272750b5d607830bbfe0e5 /drivers/dma/pl330.c | |
| parent | 05611a93b8ffa3fe7d2eb43dd6c11e37ead5908a (diff) | |
| download | linux-3e7f0bd872087bf4653eeee9a83050f91baae907.tar.bz2 | |
dmaengine: pl330: Improve transfer efficiency for the dregs
Only the unaligned burst transfers have the dregs.
so, still use BURST transfer with a reduced size
for better performance.
Signed-off-by: Sugar Zhang <sugar.zhang@rock-chips.com>
Link: https://lore.kernel.org/r/1593439555-68130-3-git-send-email-sugar.zhang@rock-chips.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma/pl330.c')
| -rw-r--r-- | drivers/dma/pl330.c | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 7686292bc1db..f1f0176c6c05 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -1228,8 +1228,9 @@ static int _bursts(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[], } /* - * transfer dregs with single transfers to peripheral, or a reduced size burst - * for mem-to-mem. + * only the unaligned burst transfers have the dregs. + * so, still transfer dregs with a reduced size burst + * for mem-to-mem, mem-to-dev or dev-to-mem. */ static int _dregs(struct pl330_dmac *pl330, unsigned int dry_run, u8 buf[], const struct _xfer_spec *pxs, int transfer_length) @@ -1240,22 +1241,31 @@ static int _dregs(struct pl330_dmac *pl330, unsigned int dry_run, u8 buf[], if (transfer_length == 0) return off; + /* + * dregs_len = (total bytes - BURST_TO_BYTE(bursts, ccr)) / + * BRST_SIZE(ccr) + * the dregs len must be smaller than burst len, + * so, for higher efficiency, we can modify CCR + * to use a reduced size burst len for the dregs. + */ + dregs_ccr = pxs->ccr; + dregs_ccr &= ~((0xf << CC_SRCBRSTLEN_SHFT) | + (0xf << CC_DSTBRSTLEN_SHFT)); + dregs_ccr |= (((transfer_length - 1) & 0xf) << + CC_SRCBRSTLEN_SHFT); + dregs_ccr |= (((transfer_length - 1) & 0xf) << + CC_DSTBRSTLEN_SHFT); + switch (pxs->desc->rqtype) { case DMA_MEM_TO_DEV: /* fall through */ case DMA_DEV_TO_MEM: - off += _ldst_peripheral(pl330, dry_run, &buf[off], pxs, - transfer_length, SINGLE); + off += _emit_MOV(dry_run, &buf[off], CCR, dregs_ccr); + off += _ldst_peripheral(pl330, dry_run, &buf[off], pxs, 1, + BURST); break; case DMA_MEM_TO_MEM: - dregs_ccr = pxs->ccr; - dregs_ccr &= ~((0xf << CC_SRCBRSTLEN_SHFT) | - (0xf << CC_DSTBRSTLEN_SHFT)); - dregs_ccr |= (((transfer_length - 1) & 0xf) << - CC_SRCBRSTLEN_SHFT); - dregs_ccr |= (((transfer_length - 1) & 0xf) << - CC_DSTBRSTLEN_SHFT); off += _emit_MOV(dry_run, &buf[off], CCR, dregs_ccr); off += _ldst_memtomem(dry_run, &buf[off], pxs, 1); break; |