From: Claudiu Beznea Date: Tue, 26 May 2026 08:46:58 +0000 (+0300) Subject: dmaengine: sh: rz-dmac: Save the start LM descriptor X-Git-Tag: v7.2-rc1~55^2~39 X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=e21aa306e82067457f2297ae56af4c91db86c59a;p=thirdparty%2Fkernel%2Flinux.git dmaengine: sh: rz-dmac: Save the start LM descriptor Save the start LM descriptor to avoid starting from the beginning of the channel's LM descriptor list in rz_dmac_calculate_residue_bytes_in_vd(). This avoids unnecessary iterations. Tested-by: John Madieu Signed-off-by: Claudiu Beznea Tested-by: Tommaso Merciai Link: https://patch.msgid.link/20260526084710.3491480-7-claudiu.beznea@kernel.org Signed-off-by: Vinod Koul --- diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c index c48858b68dee6..d3926ecd63ac1 100644 --- a/drivers/dma/sh/rz-dmac.c +++ b/drivers/dma/sh/rz-dmac.c @@ -58,6 +58,7 @@ struct rz_dmac_desc { /* For slave sg */ struct scatterlist *sg; unsigned int sgcount; + struct rz_lmdesc *start_lmdesc; }; #define to_rz_dmac_desc(d) container_of(d, struct rz_dmac_desc, vd) @@ -343,6 +344,8 @@ static void rz_dmac_prepare_desc_for_memcpy(struct rz_dmac_chan *channel) struct rz_dmac_desc *d = channel->desc; u32 chcfg = CHCFG_MEM_COPY; + d->start_lmdesc = lmdesc; + /* prepare descriptor */ lmdesc->sa = d->src; lmdesc->da = d->dest; @@ -377,6 +380,7 @@ static void rz_dmac_prepare_descs_for_slave_sg(struct rz_dmac_chan *channel) } lmdesc = channel->lmdesc.tail; + d->start_lmdesc = lmdesc; for (i = 0, sg = sgl; i < sg_len; i++, sg = sg_next(sg)) { if (d->direction == DMA_DEV_TO_MEM) { @@ -693,9 +697,10 @@ rz_dmac_get_next_lmdesc(struct rz_lmdesc *base, struct rz_lmdesc *lmdesc) return next; } -static u32 rz_dmac_calculate_residue_bytes_in_vd(struct rz_dmac_chan *channel, u32 crla) +static u32 rz_dmac_calculate_residue_bytes_in_vd(struct rz_dmac_chan *channel, + struct rz_dmac_desc *desc, u32 crla) { - struct rz_lmdesc *lmdesc = channel->lmdesc.head; + struct rz_lmdesc *lmdesc = desc->start_lmdesc; struct dma_chan *chan = &channel->vc.chan; struct rz_dmac *dmac = to_rz_dmac(chan->device); u32 residue = 0, i = 0; @@ -794,7 +799,7 @@ static u32 rz_dmac_chan_get_residue(struct rz_dmac_chan *channel, * Calculate number of bytes transferred in processing virtual descriptor. * One virtual descriptor can have many lmdesc. */ - return crtb + rz_dmac_calculate_residue_bytes_in_vd(channel, crla); + return crtb + rz_dmac_calculate_residue_bytes_in_vd(channel, current_desc, crla); } static enum dma_status rz_dmac_tx_status(struct dma_chan *chan,