On Wed, Feb 04, 2026 at 12:42:41PM -0500, Frank Li wrote:

On Wed, Feb 04, 2026 at 11:54:31PM +0900, Koichiro Den wrote:

quoted

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 <redacted>
---
 drivers/dma/dw-edma/dw-edma-core.c    | 24 +++++++++++++++++++++++
 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, 83 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 38832d9447fd..b4cb02d545bd 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c

@@ -224,6 +224,29 @@ static int dw_edma_device_config(struct dma_chan *dchan,
 				 struct dma_slave_config *config)
 {
 	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
+	const struct dw_edma_peripheral_config *pcfg;
+
+	/* peripheral_config is optional, default keeps legacy behaviour. */
+	chan->irq_mode = DW_EDMA_CH_IRQ_DEFAULT;
+
+	if (config->peripheral_config) {
+		if (chan->dw->chip->mf == EDMA_MF_HDMA_NATIVE)
+			return -EOPNOTSUPP;
+
+		if (config->peripheral_size < sizeof(*pcfg))
+			return -EINVAL;

It is good to check here.

quoted

+
+		pcfg = config->peripheral_config;

save whole peripheral_config in case need more special peripheral
configuration in future.

Ok, while I initially thought a deep copy (snapshot) was unnecessary for
now, I agree it makes future extensions easier. I'll do so.

quoted

+		switch (pcfg->irq_mode) {
+		case DW_EDMA_CH_IRQ_DEFAULT:
+		case DW_EDMA_CH_IRQ_LOCAL:
+		case DW_EDMA_CH_IRQ_REMOTE:
+			chan->irq_mode = pcfg->irq_mode;
+			break;
+		default:
+			return -EINVAL;
+		}
+	}

use helper function to get irq_mode. [...]

Ok, my current plan is to keep chan->irq_mode as sticky per-channel state,
and factor out the parsing/validation of irq_mode (from
config->peripheral_config) into a small helper used by
dw_edma_device_config() and the new prep_config path.

Does this match what you meant by "helper function"?

[...] I posted combine config and prep by
one call.

https://lore.kernel.org/dmaengine/20260105-dma_prep_config-v3-0-a8480362fd42@nxp.com/ (local)

So we use such helper to get irq node after above patch merge. It is not
big deal, I can change it later. If provide helper funtions, it will be
slice better.

quoted

 	memcpy(&chan->config, config, sizeof(*config));
 	chan->configured = true;

@@ -750,6 +773,7 @@ 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);

...

quoted

+/*
+ * 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

keep consistent after "," for each enum

Ok, will add ", local interrupt unmasked" for it.

Thanks for the review,
Koichiro

Frank

quoted

+ * @DW_EDMA_CH_IRQ_REMOTE:    LIE=1/RIE=1, local interrupt masked
+ *
+ * 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