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SubjectRe: [PATCH v2 01/13] dmaengine: pl330: Remove the burst limit for quirk 'NO-FLUSHP'
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On 2020/6/24 15:54, Vinod Koul wrote:
> 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
Thanks, I will send a v3 including these.
>
>> so, remove the limit to improve the efficiency.
>>
>> Signed-off-by: Sugar Zhang <sugar.zhang@rock-chips.com>
>> ---
>>
>> 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
ok, I will split this patch in v3.
>> */
>> 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
>>
>>
--



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