> -----Original Message-----
> From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> Sent: Wednesday, April 5, 2023 3:09 PM
> To: Vinod Koul <vkoul@xxxxxxxxxx>
> Cc: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>; Geert Uytterhoeven
> <geert+renesas@xxxxxxxxx>; Prabhakar Mahadev Lad <prabhakar.mahadev-
> lad.rj@xxxxxxxxxxxxxx>; dmaengine@xxxxxxxxxxxxxxx; linux-renesas-
> soc@xxxxxxxxxxxxxxx
> Subject: [PATCH v2 5/5] dmaengine: sh: rz-dmac:
> rz_dmac_prepare_descs_for_slave_sg() improvements
>
> Some code improvements for rz_dmac_prepare_descs_for_slave_sg().
>
> Replace the loop for->for_each_sg and drop the variables sgl and sg_len.
> Also improve the logic for assigning lmdesc->chcfg and lmdesc->header and
> lastly, add lmdesc assignment along with the declaration.
>
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> ---
> v2:
> * New patch.
> ---
> drivers/dma/sh/rz-dmac.c | 22 +++++++++-------------
> 1 file changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c index
> 153893045932..c6150d7ae8a7 100644
> --- a/drivers/dma/sh/rz-dmac.c
> +++ b/drivers/dma/sh/rz-dmac.c
> @@ -342,12 +342,12 @@ static void rz_dmac_prepare_desc_for_memcpy(struct
> rz_dmac_chan *channel)
>
> static void rz_dmac_prepare_descs_for_slave_sg(struct rz_dmac_chan
> *channel) {
> + struct rz_lmdesc *lmdesc = channel->lmdesc.tail;
> struct dma_chan *chan = &channel->vc.chan;
> struct rz_dmac *dmac = to_rz_dmac(chan->device);
> struct rz_dmac_desc *d = channel->desc;
> - struct scatterlist *sg, *sgl = d->sg;
> - struct rz_lmdesc *lmdesc;
> - unsigned int i, sg_len = d->sgcount;
> + struct scatterlist *sg;
> + unsigned int i;
>
> channel->chcfg |= CHCFG_SEL(channel->index) | CHCFG_DEM | CHCFG_DMS;
>
> @@ -358,9 +358,7 @@ static void rz_dmac_prepare_descs_for_slave_sg(struct
> rz_dmac_chan *channel)
> channel->chcfg |= CHCFG_DAD | CHCFG_REQD;
> }
>
> - lmdesc = channel->lmdesc.tail;
> -
> - for (i = 0, sg = sgl; i < sg_len; i++, sg = sg_next(sg)) {
> + for_each_sg(d->sg, sg, d->sgcount, i) {
> if (d->direction == DMA_DEV_TO_MEM) {
> lmdesc->sa = channel->src_per_address;
> lmdesc->da = sg_dma_address(sg);
> @@ -372,13 +370,11 @@ static void rz_dmac_prepare_descs_for_slave_sg(struct
> rz_dmac_chan *channel)
> lmdesc->tb = sg_dma_len(sg);
> lmdesc->chitvl = 0;
> lmdesc->chext = 0;
> - if (i == (sg_len - 1)) {
> - lmdesc->chcfg = (channel->chcfg & ~CHCFG_DEM);
> - lmdesc->header = HEADER_LV;
> - } else {
> - lmdesc->chcfg = channel->chcfg;
> - lmdesc->header = HEADER_LV;
> - }
> + lmdesc->chcfg = channel->chcfg;
> + lmdesc->header = HEADER_LV;
> + if (i == (d->sgcount - 1))
> + lmdesc->chcfg &= ~CHCFG_DEM;
To match with previous code flow,
lmdesc->header = HEADER_LV; should be after lmdesc->chcfg &= ~CHCFG_DEM;
I will change this in next version.
Cheers,
Biju
> +
> if (++lmdesc >= (channel->lmdesc.base + DMAC_NR_LMDESC))
> lmdesc = channel->lmdesc.base;
> }
> --
> 2.25.1
