There is no reason to limit the performance on the 'NO-FLUSHP' SoCs,
cuz these platforms are just that the 'FLUSHP' instruction is broken.
so, remove the limit to improve the efficiency.
Signed-off-by: Sugar Zhang <sugar.zhang@xxxxxxxxxxxxxx>
---
Changes in v2: None
drivers/dma/pl330.c | 34 ++++++++++++++++++++++------------
1 file changed, 22 insertions(+), 12 deletions(-)
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 6a158ee..ff0a91f 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -1183,9 +1183,6 @@ static inline int _ldst_peripheral(struct pl330_dmac *pl330,
{
int off = 0;
- if (pl330->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP)
- cond = BURST;
-
/*
* do FLUSHP at beginning to clear any stale dma requests before the
* first WFP.
@@ -1231,8 +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 bursts transfers have the dregs.
+ * transfer dregs with a reduced size burst to peripheral,
+ * or a reduced size burst for mem-to-mem.
*/
static int _dregs(struct pl330_dmac *pl330, unsigned int dry_run, u8 buf[],
const struct _xfer_spec *pxs, int transfer_length)
@@ -1247,8 +1245,23 @@ static int _dregs(struct pl330_dmac *pl330, unsigned int dry_run, u8 buf[],
case DMA_MEM_TO_DEV:
/* fall through */
case DMA_DEV_TO_MEM:
- off += _ldst_peripheral(pl330, dry_run, &buf[off], pxs,
- transfer_length, SINGLE);
+ /*
+ * 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);
+ 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:
@@ -2221,9 +2234,7 @@ static bool pl330_prep_slave_fifo(struct dma_pl330_chan *pch,
static int fixup_burst_len(int max_burst_len, int quirks)
{
- if (quirks & PL330_QUIRK_BROKEN_NO_FLUSHP)
- return 1;
- else if (max_burst_len > PL330_MAX_BURST)
+ if (max_burst_len > PL330_MAX_BURST)
return PL330_MAX_BURST;
else if (max_burst_len < 1)
return 1;
@@ -3128,8 +3139,7 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
pd->dst_addr_widths = PL330_DMA_BUSWIDTHS;
pd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
pd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
- pd->max_burst = ((pl330->quirks & PL330_QUIRK_BROKEN_NO_FLUSHP) ?
- 1 : PL330_MAX_BURST);
+ pd->max_burst = PL330_MAX_BURST;
ret = dma_async_device_register(pd);
if (ret) {
--
2.7.4
