On 09-06-20, 09:14, Sugar Zhang wrote:
> There is no reason to limit the performance on the 'NO-FLUSHP' SoCs,
> cuz these platforms are just that the 'FLUSHP' instruction is broken.
Lets not use terms like cuz... 'because' is perfect term :)
It can rephrased to:
There is no reason to limit the performance on the 'NO-FLUSHP' SoCs
beacuse 'FLUSHP' instruction is broken on these platforms, so remove the
limit to improve the efficiency
> 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.
This is not related to broken flush and should be a different patch
explaining why this changes were done
> */
> 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
>
>
--
~Vinod
