Re: [PATCH v3 02/13] dmaengine: dw-edma: Add core quiesce operations

[Frank Li]

On Sun, Jun 21, 2026 at 02:00:29AM +0900, Koichiro Den wrote:
> Add core operations that quiesce only the resources represented by a
> dw-edma instance, separate from the existing full controller off path.
>
> For v0 eDMA and HDMA compatible register layouts, quiescing one channel
> must quiesce the whole direction because the enable and interrupt
> mask/clear registers are direction-wide. For HDMA native, the operation
> can quiesce the represented per-channel registers directly.
>
> No caller is added yet, so this is a no-functional-change preparation
> for delegated channel reclaim and partial-owned remove paths.
>
> Signed-off-by: Koichiro Den <den@xxxxxxxxxxxxx>
> ---

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>

> Changes in v3:
>   - New patch. Add quiesce primitives before delegated-channel release
>     and partial-owned remove start using them.
>   - Note: Devendra's under-review "dmaengine: dw-edma: Enable HDMA 64R/W
>     Channels" series may require a follow-up rebase if it lands first.
>
>  drivers/dma/dw-edma/dw-edma-core.h    | 14 ++++++++++++++
>  drivers/dma/dw-edma/dw-edma-v0-core.c | 24 ++++++++++++++++++++++++
>  drivers/dma/dw-edma/dw-hdma-v0-core.c | 27 +++++++++++++++++++++++++++
>  3 files changed, 65 insertions(+)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
> index 42f2f25ef377..f9d4e0411f8f 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.h
> +++ b/drivers/dma/dw-edma/dw-edma-core.h
> @@ -122,6 +122,8 @@ typedef void (*dw_edma_handler_t)(struct dw_edma_chan *);
>
>  struct dw_edma_core_ops {
>  	void (*off)(struct dw_edma *dw);
> +	void (*quiesce)(struct dw_edma *dw);
> +	void (*ch_quiesce)(struct dw_edma_chan *chan);
>  	u16 (*ch_count)(struct dw_edma *dw, enum dw_edma_dir dir);
>  	enum dma_status (*ch_status)(struct dw_edma_chan *chan);
>  	irqreturn_t (*handle_int)(struct dw_edma_irq *dw_irq, enum dw_edma_dir dir,
> @@ -174,6 +176,18 @@ void dw_edma_core_off(struct dw_edma *dw)
>  	dw->core->off(dw);
>  }
>
> +static inline
> +void dw_edma_core_quiesce(struct dw_edma *dw)
> +{
> +	dw->core->quiesce(dw);
> +}
> +
> +static inline
> +void dw_edma_core_ch_quiesce(struct dw_edma_chan *chan)
> +{
> +	chan->dw->core->ch_quiesce(chan);
> +}
> +
>  static inline
>  u16 dw_edma_core_ch_count(struct dw_edma *dw, enum dw_edma_dir dir)
>  {
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
> index 1781ba4f022e..316d8c94eff9 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
> @@ -160,6 +160,15 @@ static inline u32 readl_ch(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch,
>  	readl_ch(dw, dir, ch, &(__dw_ch_regs(dw, dir, ch)->name))
>
>  /* eDMA management callbacks */
> +static void dw_edma_v0_core_dir_off(struct dw_edma *dw, enum dw_edma_dir dir)
> +{
> +	SET_RW_32(dw, dir, int_mask,
> +		  EDMA_V0_DONE_INT_MASK | EDMA_V0_ABORT_INT_MASK);
> +	SET_RW_32(dw, dir, int_clear,
> +		  EDMA_V0_DONE_INT_MASK | EDMA_V0_ABORT_INT_MASK);
> +	SET_RW_32(dw, dir, engine_en, 0);
> +}
> +
>  static void dw_edma_v0_core_off(struct dw_edma *dw)
>  {
>  	SET_BOTH_32(dw, int_mask,
> @@ -169,6 +178,19 @@ static void dw_edma_v0_core_off(struct dw_edma *dw)
>  	SET_BOTH_32(dw, engine_en, 0);
>  }
>
> +static void dw_edma_v0_core_quiesce(struct dw_edma *dw)
> +{
> +	if (dw->wr_ch_cnt)
> +		dw_edma_v0_core_dir_off(dw, EDMA_DIR_WRITE);
> +	if (dw->rd_ch_cnt)
> +		dw_edma_v0_core_dir_off(dw, EDMA_DIR_READ);
> +}
> +
> +static void dw_edma_v0_core_ch_quiesce(struct dw_edma_chan *chan)
> +{
> +	dw_edma_v0_core_dir_off(chan->dw, chan->dir);
> +}
> +
>  static u16 dw_edma_v0_core_ch_count(struct dw_edma *dw, enum dw_edma_dir dir)
>  {
>  	u32 num_ch;
> @@ -546,6 +568,8 @@ static resource_size_t dw_edma_v0_core_db_offset(struct dw_edma *dw)
>
>  static const struct dw_edma_core_ops dw_edma_v0_core = {
>  	.off = dw_edma_v0_core_off,
> +	.quiesce = dw_edma_v0_core_quiesce,
> +	.ch_quiesce = dw_edma_v0_core_ch_quiesce,
>  	.ch_count = dw_edma_v0_core_ch_count,
>  	.ch_status = dw_edma_v0_core_ch_status,
>  	.handle_int = dw_edma_v0_core_handle_int,
> diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> index 7ba6bdbffc17..63c30a6eb88c 100644
> --- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
> +++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> @@ -70,6 +70,16 @@ static u32 dw_hdma_v0_core_int_setup(struct dw_edma_chan *chan, u32 val)
>  }
>
>  /* HDMA management callbacks */
> +static void dw_hdma_v0_core_ch_off(struct dw_edma *dw, enum dw_edma_dir dir,
> +				   u16 id)
> +{
> +	SET_CH_32(dw, dir, id, int_setup,
> +		  HDMA_V0_STOP_INT_MASK | HDMA_V0_ABORT_INT_MASK);
> +	SET_CH_32(dw, dir, id, int_clear,
> +		  HDMA_V0_STOP_INT_MASK | HDMA_V0_ABORT_INT_MASK);
> +	SET_CH_32(dw, dir, id, ch_en, 0);
> +}
> +
>  static void dw_hdma_v0_core_off(struct dw_edma *dw)
>  {
>  	int id;
> @@ -83,6 +93,21 @@ static void dw_hdma_v0_core_off(struct dw_edma *dw)
>  	}
>  }
>
> +static void dw_hdma_v0_core_quiesce(struct dw_edma *dw)
> +{
> +	int id;
> +
> +	for (id = 0; id < dw->wr_ch_cnt; id++)
> +		dw_hdma_v0_core_ch_off(dw, EDMA_DIR_WRITE, id);
> +	for (id = 0; id < dw->rd_ch_cnt; id++)
> +		dw_hdma_v0_core_ch_off(dw, EDMA_DIR_READ, id);
> +}
> +
> +static void dw_hdma_v0_core_ch_quiesce(struct dw_edma_chan *chan)
> +{
> +	dw_hdma_v0_core_ch_off(chan->dw, chan->dir, chan->id);
> +}
> +
>  static u16 dw_hdma_v0_core_ch_count(struct dw_edma *dw, enum dw_edma_dir dir)
>  {
>  	/*
> @@ -362,6 +387,8 @@ static resource_size_t dw_hdma_v0_core_db_offset(struct dw_edma *dw)
>
>  static const struct dw_edma_core_ops dw_hdma_v0_core = {
>  	.off = dw_hdma_v0_core_off,
> +	.quiesce = dw_hdma_v0_core_quiesce,
> +	.ch_quiesce = dw_hdma_v0_core_ch_quiesce,
>  	.ch_count = dw_hdma_v0_core_ch_count,
>  	.ch_status = dw_hdma_v0_core_ch_status,
>  	.handle_int = dw_hdma_v0_core_handle_int,
> --
> 2.51.0
>