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Message-ID: <aYYoWtkM0EhP1Od9@lizhi-Precision-Tower-5810>
Date: Fri, 6 Feb 2026 12:43:54 -0500
From: Frank Li <Frank.li@....com>
To: Koichiro Den <den@...inux.co.jp>
Cc: vkoul@...nel.org, mani@...nel.org, jingoohan1@...il.com,
lpieralisi@...nel.org, kwilczynski@...nel.org, robh@...nel.org,
bhelgaas@...gle.com, dmaengine@...r.kernel.org,
linux-pci@...r.kernel.org, linux-kselftest@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/9] dmaengine: dw-edma: Add per-channel interrupt
routing control
On Sat, Feb 07, 2026 at 02:26:38AM +0900, Koichiro Den wrote:
> DesignWare EP eDMA can generate interrupts both locally and remotely
> (LIE/RIE). Remote eDMA users need to decide, per channel, whether
> completions should be handled locally, remotely, or both. Unless
> carefully configured, the endpoint and host would race to ack the
> interrupt.
>
> Introduce a dw_edma_peripheral_config that holds per-channel interrupt
> routing mode. Update v0 programming so that RIE and local done/abort
> interrupt masking follow the selected mode. The default mode keeps the
> original behavior, so unless the new peripheral_config is explicitly
> used and set, no functional changes.
>
> For now, HDMA is not supported for the peripheral_config. Until the
> support is implemented and validated, explicitly reject it for HDMA to
> avoid silently misconfiguring interrupt routing.
>
> Signed-off-by: Koichiro Den <den@...inux.co.jp>
> ---
> drivers/dma/dw-edma/dw-edma-core.c | 37 +++++++++++++++++++++++++++
> drivers/dma/dw-edma/dw-edma-core.h | 13 ++++++++++
> drivers/dma/dw-edma/dw-edma-v0-core.c | 26 +++++++++++++------
> include/linux/dma/edma.h | 28 ++++++++++++++++++++
> 4 files changed, 96 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index 8e5f7defa6b6..0c3461f9174a 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -219,11 +219,47 @@ static void dw_edma_device_caps(struct dma_chan *dchan,
> }
> }
>
> +static int dw_edma_parse_irq_mode(struct dw_edma_chan *chan,
> + const struct dma_slave_config *config,
> + enum dw_edma_ch_irq_mode *mode)
> +{
> + const struct dw_edma_peripheral_config *pcfg;
> +
> + /* peripheral_config is optional, default keeps legacy behaviour. */
> + *mode = DW_EDMA_CH_IRQ_DEFAULT;
> + if (!config || !config->peripheral_config)
> + return 0;
> +
> + if (chan->dw->chip->mf == EDMA_MF_HDMA_NATIVE)
> + return -EOPNOTSUPP;
> +
> + if (config->peripheral_size < sizeof(*pcfg))
> + return -EINVAL;
> +
> + pcfg = config->peripheral_config;
> + switch (pcfg->irq_mode) {
> + case DW_EDMA_CH_IRQ_DEFAULT:
> + case DW_EDMA_CH_IRQ_LOCAL:
> + case DW_EDMA_CH_IRQ_REMOTE:
> + *mode = pcfg->irq_mode;
> + return 0;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> static int dw_edma_device_config(struct dma_chan *dchan,
> struct dma_slave_config *config)
> {
> struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> + enum dw_edma_ch_irq_mode mode;
> + int ret;
> +
> + ret = dw_edma_parse_irq_mode(chan, config, &mode);
> + if (ret)
> + return ret;
>
> + chan->irq_mode = mode;
> memcpy(&chan->config, config, sizeof(*config));
> chan->configured = true;
>
> @@ -749,6 +785,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
> chan->configured = false;
> chan->request = EDMA_REQ_NONE;
> chan->status = EDMA_ST_IDLE;
> + chan->irq_mode = DW_EDMA_CH_IRQ_DEFAULT;
>
> if (chan->dir == EDMA_DIR_WRITE)
> chan->ll_max = (chip->ll_region_wr[chan->id].sz / EDMA_LL_SZ);
> diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
> index 71894b9e0b15..0608b9044a08 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.h
> +++ b/drivers/dma/dw-edma/dw-edma-core.h
> @@ -81,6 +81,8 @@ struct dw_edma_chan {
>
> struct msi_msg msi;
>
> + enum dw_edma_ch_irq_mode irq_mode;
> +
> enum dw_edma_request request;
> enum dw_edma_status status;
> u8 configured;
> @@ -206,4 +208,15 @@ void dw_edma_core_debugfs_on(struct dw_edma *dw)
> dw->core->debugfs_on(dw);
> }
>
> +static inline
> +bool dw_edma_core_ch_ignore_irq(struct dw_edma_chan *chan)
nit:
static inline bool
dw_edma_core_ch_ignore_irq()
> +{
> + struct dw_edma *dw = chan->dw;
> +
> + if (dw->chip->flags & DW_EDMA_CHIP_LOCAL)
> + return chan->irq_mode == DW_EDMA_CH_IRQ_REMOTE;
> + else
> + return chan->irq_mode == DW_EDMA_CH_IRQ_LOCAL;
> +}
> +
> #endif /* _DW_EDMA_CORE_H */
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
> index b75fdaffad9a..a0441e8aa3b3 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
> @@ -256,8 +256,10 @@ dw_edma_v0_core_handle_int(struct dw_edma_irq *dw_irq, enum dw_edma_dir dir,
> for_each_set_bit(pos, &val, total) {
> chan = &dw->chan[pos + off];
>
> - dw_edma_v0_core_clear_done_int(chan);
> - done(chan);
> + if (!dw_edma_core_ch_ignore_irq(chan)) {
> + dw_edma_v0_core_clear_done_int(chan);
> + done(chan);
> + }
>
> ret = IRQ_HANDLED;
> }
> @@ -267,8 +269,10 @@ dw_edma_v0_core_handle_int(struct dw_edma_irq *dw_irq, enum dw_edma_dir dir,
> for_each_set_bit(pos, &val, total) {
> chan = &dw->chan[pos + off];
>
> - dw_edma_v0_core_clear_abort_int(chan);
> - abort(chan);
> + if (!dw_edma_core_ch_ignore_irq(chan)) {
> + dw_edma_v0_core_clear_abort_int(chan);
> + abort(chan);
> + }
>
> ret = IRQ_HANDLED;
> }
> @@ -331,7 +335,8 @@ static void dw_edma_v0_core_write_chunk(struct dw_edma_chunk *chunk)
> j--;
> if (!j) {
> control |= DW_EDMA_V0_LIE;
> - if (!(chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL))
> + if (!(chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) &&
> + chan->irq_mode != DW_EDMA_CH_IRQ_LOCAL)
> control |= DW_EDMA_V0_RIE;
> }
>
> @@ -407,10 +412,15 @@ static void dw_edma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
> break;
> }
> }
> - /* Interrupt unmask - done, abort */
> + /* Interrupt mask/unmask - done, abort */
> tmp = GET_RW_32(dw, chan->dir, int_mask);
> - tmp &= ~FIELD_PREP(EDMA_V0_DONE_INT_MASK, BIT(chan->id));
> - tmp &= ~FIELD_PREP(EDMA_V0_ABORT_INT_MASK, BIT(chan->id));
> + if (chan->irq_mode == DW_EDMA_CH_IRQ_REMOTE) {
> + tmp |= FIELD_PREP(EDMA_V0_DONE_INT_MASK, BIT(chan->id));
> + tmp |= FIELD_PREP(EDMA_V0_ABORT_INT_MASK, BIT(chan->id));
> + } else {
> + tmp &= ~FIELD_PREP(EDMA_V0_DONE_INT_MASK, BIT(chan->id));
> + tmp &= ~FIELD_PREP(EDMA_V0_ABORT_INT_MASK, BIT(chan->id));
> + }
> SET_RW_32(dw, chan->dir, int_mask, tmp);
> /* Linked list error */
> tmp = GET_RW_32(dw, chan->dir, linked_list_err_en);
> diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
> index 3080747689f6..53b31a974331 100644
> --- a/include/linux/dma/edma.h
> +++ b/include/linux/dma/edma.h
> @@ -60,6 +60,34 @@ enum dw_edma_chip_flags {
> DW_EDMA_CHIP_LOCAL = BIT(0),
> };
>
> +/*
> + * enum dw_edma_ch_irq_mode - per-channel interrupt routing control
> + * @DW_EDMA_CH_IRQ_DEFAULT: LIE=1/RIE=1, local interrupt unmasked
> + * @DW_EDMA_CH_IRQ_LOCAL: LIE=1/RIE=0, local interrupt unmasked
> + * @DW_EDMA_CH_IRQ_REMOTE: LIE=1/RIE=1, local interrupt masked
You'd better descript remote interrupt also.
Reviewed-by: Frank Li <Frank.Li@....com>
> + *
> + * Some implementations require using LIE=1/RIE=1 with the local interrupt
> + * masked to generate a remote-only interrupt (rather than LIE=0/RIE=1).
> + * See the DesignWare endpoint databook 5.40, "Hint" below "Figure 8-22
> + * Write Interrupt Generation".
> + */
> +enum dw_edma_ch_irq_mode {
> + DW_EDMA_CH_IRQ_DEFAULT = 0,
> + DW_EDMA_CH_IRQ_LOCAL,
> + DW_EDMA_CH_IRQ_REMOTE,
> +};
> +
> +/**
> + * struct dw_edma_peripheral_config - dw-edma specific slave configuration
> + * @irq_mode: per-channel interrupt routing control.
> + *
> + * Pass this structure via dma_slave_config.peripheral_config and
> + * dma_slave_config.peripheral_size.
> + */
> +struct dw_edma_peripheral_config {
> + enum dw_edma_ch_irq_mode irq_mode;
> +};
> +
> /**
> * struct dw_edma_chip - representation of DesignWare eDMA controller hardware
> * @dev: struct device of the eDMA controller
> --
> 2.51.0
>
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