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SubjectRe: [PATCH 3/5] dma: optimize two stage transfer function
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On 8/7/2023 1:20 PM, Kaiwei Liu wrote:
> The DMA hardware is updated to optimize two stages transmission
> function, so modify relative register and logic. Two
> stages transmission mode of dma allows one channel finished
> transmission then start another channel transfer automatically.
>
> Signed-off-by: Kaiwei Liu <kaiwei.liu@unisoc.com>
> ---
> drivers/dma/sprd-dma.c | 124 ++++++++++++++++++++++++++++++-----------
> 1 file changed, 91 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
> index 0e146550dfbb..01053e106e8a 100644
> --- a/drivers/dma/sprd-dma.c
> +++ b/drivers/dma/sprd-dma.c
> @@ -68,6 +68,7 @@
> #define SPRD_DMA_GLB_TRANS_DONE_TRG BIT(18)
> #define SPRD_DMA_GLB_BLOCK_DONE_TRG BIT(17)
> #define SPRD_DMA_GLB_FRAG_DONE_TRG BIT(16)
> +#define SPRD_DMA_GLB_TRG_MASK GENMASK(19, 16)
> #define SPRD_DMA_GLB_TRG_OFFSET 16
> #define SPRD_DMA_GLB_DEST_CHN_MASK GENMASK(13, 8)
> #define SPRD_DMA_GLB_DEST_CHN_OFFSET 8
> @@ -155,6 +156,13 @@
>
> #define SPRD_DMA_SOFTWARE_UID 0
>
> +#define SPRD_DMA_SRC_CHN0_INT 9
> +#define SPRD_DMA_SRC_CHN1_INT 10
> +#define SPRD_DMA_DST_CHN0_INT 11
> +#define SPRD_DMA_DST_CHN1_INT 12
> +#define SPRD_DMA_2STAGE_SET 1
> +#define SPRD_DMA_2STAGE_CLEAR 0

This 2 are not hardware definition, and I don't think they are helpful,
just use a boolean parameter.

> +
> /* dma data width values */
> enum sprd_dma_datawidth {
> SPRD_DMA_DATAWIDTH_1_BYTE,
> @@ -212,7 +220,7 @@ struct sprd_dma_dev {
> struct clk *ashb_clk;
> int irq;
> u32 total_chns;
> - struct sprd_dma_chn channels[];
> + struct sprd_dma_chn channels[0];

Please remove redundant changes.

> };
>
> static void sprd_dma_free_desc(struct virt_dma_desc *vd);
> @@ -431,50 +439,90 @@ static enum sprd_dma_req_mode sprd_dma_get_req_type(struct sprd_dma_chn *schan)
> return (frag_reg >> SPRD_DMA_REQ_MODE_OFFSET) & SPRD_DMA_REQ_MODE_MASK;
> }
>
> -static int sprd_dma_set_2stage_config(struct sprd_dma_chn *schan)
> +static int sprd_dma_2stage_config(struct sprd_dma_chn *schan, u32 config_type)

Why change the function name? 'config_type' should be boolean.

> {
> struct sprd_dma_dev *sdev = to_sprd_dma_dev(&schan->vc.chan);
> u32 val, chn = schan->chn_num + 1;
>
> switch (schan->chn_mode) {
> case SPRD_DMA_SRC_CHN0:
> - val = chn & SPRD_DMA_GLB_SRC_CHN_MASK;
> - val |= BIT(schan->trg_mode - 1) << SPRD_DMA_GLB_TRG_OFFSET;
> - val |= SPRD_DMA_GLB_2STAGE_EN;
> - if (schan->int_type != SPRD_DMA_NO_INT)
> - val |= SPRD_DMA_GLB_SRC_INT;
> -
> - sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP1, val, val);
> + if (config_type == SPRD_DMA_2STAGE_SET) {
> + val = chn & SPRD_DMA_GLB_SRC_CHN_MASK;
> + val |= BIT(schan->trg_mode - 1) << SPRD_DMA_GLB_TRG_OFFSET;
> + val |= SPRD_DMA_GLB_2STAGE_EN;
> + if (schan->int_type & SPRD_DMA_SRC_CHN0_INT)

can you explain why change the interrupt validation? ignore other
interrupt type?

> + val |= SPRD_DMA_GLB_SRC_INT;
> +
> + sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP1,
> + SPRD_DMA_GLB_SRC_INT |
> + SPRD_DMA_GLB_TRG_MASK |
> + SPRD_DMA_GLB_SRC_CHN_MASK, val);
> + } else {
> + sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP1,
> + SPRD_DMA_GLB_SRC_INT |
> + SPRD_DMA_GLB_TRG_MASK |
> + SPRD_DMA_GLB_2STAGE_EN |
> + SPRD_DMA_GLB_SRC_CHN_MASK, 0);
> + }
> break;
>
> case SPRD_DMA_SRC_CHN1:
> - val = chn & SPRD_DMA_GLB_SRC_CHN_MASK;
> - val |= BIT(schan->trg_mode - 1) << SPRD_DMA_GLB_TRG_OFFSET;
> - val |= SPRD_DMA_GLB_2STAGE_EN;
> - if (schan->int_type != SPRD_DMA_NO_INT)
> - val |= SPRD_DMA_GLB_SRC_INT;
> -
> - sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP2, val, val);
> + if (config_type == SPRD_DMA_2STAGE_SET) {
> + val = chn & SPRD_DMA_GLB_SRC_CHN_MASK;
> + val |= BIT(schan->trg_mode - 1) << SPRD_DMA_GLB_TRG_OFFSET;
> + val |= SPRD_DMA_GLB_2STAGE_EN;
> + if (schan->int_type & SPRD_DMA_SRC_CHN1_INT)
> + val |= SPRD_DMA_GLB_SRC_INT;
> +
> + sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP2,
> + SPRD_DMA_GLB_SRC_INT |
> + SPRD_DMA_GLB_TRG_MASK |
> + SPRD_DMA_GLB_SRC_CHN_MASK, val);
> + } else {
> + sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP2,
> + SPRD_DMA_GLB_SRC_INT |
> + SPRD_DMA_GLB_TRG_MASK |
> + SPRD_DMA_GLB_2STAGE_EN |
> + SPRD_DMA_GLB_SRC_CHN_MASK, 0);
> + }
> break;
>
> case SPRD_DMA_DST_CHN0:
> - val = (chn << SPRD_DMA_GLB_DEST_CHN_OFFSET) &
> - SPRD_DMA_GLB_DEST_CHN_MASK;
> - val |= SPRD_DMA_GLB_2STAGE_EN;
> - if (schan->int_type != SPRD_DMA_NO_INT)
> - val |= SPRD_DMA_GLB_DEST_INT;
> -
> - sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP1, val, val);
> + if (config_type == SPRD_DMA_2STAGE_SET) {
> + val = (chn << SPRD_DMA_GLB_DEST_CHN_OFFSET) &
> + SPRD_DMA_GLB_DEST_CHN_MASK;
> + val |= SPRD_DMA_GLB_2STAGE_EN;
> + if (schan->int_type & SPRD_DMA_DST_CHN0_INT)
> + val |= SPRD_DMA_GLB_DEST_INT;
> +
> + sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP1,
> + SPRD_DMA_GLB_DEST_INT |
> + SPRD_DMA_GLB_DEST_CHN_MASK, val);
> + } else {
> + sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP1,
> + SPRD_DMA_GLB_DEST_INT |
> + SPRD_DMA_GLB_2STAGE_EN |
> + SPRD_DMA_GLB_DEST_CHN_MASK, 0);
> + }
> break;
>
> case SPRD_DMA_DST_CHN1:
> - val = (chn << SPRD_DMA_GLB_DEST_CHN_OFFSET) &
> - SPRD_DMA_GLB_DEST_CHN_MASK;
> - val |= SPRD_DMA_GLB_2STAGE_EN;
> - if (schan->int_type != SPRD_DMA_NO_INT)
> - val |= SPRD_DMA_GLB_DEST_INT;
> -
> - sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP2, val, val);
> + if (config_type == SPRD_DMA_2STAGE_SET) {
> + val = (chn << SPRD_DMA_GLB_DEST_CHN_OFFSET) &
> + SPRD_DMA_GLB_DEST_CHN_MASK;
> + val |= SPRD_DMA_GLB_2STAGE_EN;
> + if (schan->int_type & SPRD_DMA_DST_CHN1_INT)
> + val |= SPRD_DMA_GLB_DEST_INT;
> +
> + sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP2,
> + SPRD_DMA_GLB_DEST_INT |
> + SPRD_DMA_GLB_DEST_CHN_MASK, val);
> + } else {
> + sprd_dma_glb_update(sdev, SPRD_DMA_GLB_2STAGE_GRP2,
> + SPRD_DMA_GLB_DEST_INT |
> + SPRD_DMA_GLB_2STAGE_EN |
> + SPRD_DMA_GLB_DEST_CHN_MASK, 0);
> + }
> break;
>
> default:
> @@ -545,7 +593,7 @@ static void sprd_dma_start(struct sprd_dma_chn *schan)
> * Set 2-stage configuration if the channel starts one 2-stage
> * transfer.
> */
> - if (schan->chn_mode && sprd_dma_set_2stage_config(schan))
> + if (schan->chn_mode && sprd_dma_2stage_config(schan, SPRD_DMA_2STAGE_SET))
> return;
>
> /*
> @@ -569,6 +617,12 @@ static void sprd_dma_stop(struct sprd_dma_chn *schan)
> sprd_dma_set_pending(schan, false);
> sprd_dma_unset_uid(schan);
> sprd_dma_clear_int(schan);
> + /*
> + * If 2-stage transfer is used, the configuration must be clear
> + * when release DMA channel.

Please explain why? not only 'what'.

> + */
> + if (schan->chn_mode)
> + sprd_dma_2stage_config(schan, SPRD_DMA_2STAGE_CLEAR);

How to ensure backward compatibility with previous SPRD DMA IP?

> schan->cur_desc = NULL;
> }
>
> @@ -757,7 +811,9 @@ static int sprd_dma_fill_desc(struct dma_chan *chan,
> phys_addr_t llist_ptr;
>
> if (dir == DMA_MEM_TO_DEV) {
> - src_step = sprd_dma_get_step(slave_cfg->src_addr_width);
> + src_step = slave_cfg->src_port_window_size ?
> + slave_cfg->src_port_window_size :
> + sprd_dma_get_step(slave_cfg->src_addr_width);

Please also explain why.

> if (src_step < 0) {
> dev_err(sdev->dma_dev.dev, "invalid source step\n");
> return src_step;
> @@ -773,7 +829,9 @@ static int sprd_dma_fill_desc(struct dma_chan *chan,
> else
> dst_step = SPRD_DMA_NONE_STEP;
> } else {
> - dst_step = sprd_dma_get_step(slave_cfg->dst_addr_width);
> + dst_step = slave_cfg->dst_port_window_size ?
> + slave_cfg->dst_port_window_size :
> + sprd_dma_get_step(slave_cfg->dst_addr_width);
> if (dst_step < 0) {
> dev_err(sdev->dma_dev.dev, "invalid destination step\n");
> return dst_step;

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