[PATCH v2 0/3] dmaengine: dw-edma: Prepare channels for remote use

[PATCH v2 0/3] dmaengine: dw-edma: Prepare channels for remote use

[Koichiro Den]

Hi,

This small series contains standalone refactoring and new infrastructure
for dmaengine and dw-edma.

For each patch, the commit message trailer describes its provenance,
keeping tags (incl. Reviewed-by) as-is.

It prepares PCIe EPC-local DMA channels for remote use. For context,
(b) is expected to be superseded by a reworked version of (a):

  (a). vNTB-embedded v1
       https://lore.kernel.org/r/20260312165005.1148676-1-den@valinux.co.jp/
  (b). PCI DMA EPF v7
       https://lore.kernel.org/all/20260813063757.3131865-1-den@valinux.co.jp/

I will post a reworked version of (a) shortly. It will depend on this
small series.

Best regards,
Koichiro
---
Changes in v2:
  - Split and rework vNTB v1 patches 1, 4, and 5 into this prerequisite
    series.
  - Fold in the relevant PCI DMA EPF v7 review. See individual patch
    trailers for details and links.

v1: https://lore.kernel.org/r/20260312165005.1148676-1-den@valinux.co.jp/


Koichiro Den (3):
  dmaengine: Allow drivers to assign static channel IDs
  dmaengine: dw-edma: Configure remote interrupt routing
  dmaengine: dw-edma: Account for the MSI vector offset

 drivers/dma/dmaengine.c            | 13 +++--
 drivers/dma/dw-edma/dw-edma-core.c | 76 ++++++++++++++++++++++++------
 include/linux/dma/edma.h           |  6 +++
 include/linux/dmaengine.h          | 20 ++++++++
 4 files changed, 96 insertions(+), 19 deletions(-)


base-commit: 0d995da5fb97e8c312834575604d4423eb6225b7
-- 
2.51.0

[PATCH v2 1/3] dmaengine: Allow drivers to assign static channel IDs

[Koichiro Den]

The dmaengine core assigns channel IDs in registration order. If a driver
skips a hardware channel, chan_id can differ from the hardware numbering
and a client cannot reliably correlate a requested channel with hardware
resources.

Let a driver request an exact channel ID before device registration.
Reserve static IDs through the existing IDA so they remain unique, while
retaining automatic IDA allocation as the default.

For example, idma32 uses chan_id to select DMA_CTL_CH() and
DMA_XBAR_SEL(), so it relies on ascending registration order to match
chan_id with the hardware channel number.

Use direction-flattened IDs for dw-edma channels. Unlike the
direction-local hardware channel number, these IDs are unique within the
DMA device.

Suggested-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
Changes in v2:
  - Carry over PCI DMA EPF v7 patch 1.
    https://lore.kernel.org/r/20260813063757.3131865-2-den@valinux.co.jp/
  - Add the idma32 example requested during v7 review. (Frank)
    https://lore.kernel.org/r/an4TXwT37vWYEzCn@SMW015318/

 drivers/dma/dmaengine.c            | 13 ++++++++-----
 drivers/dma/dw-edma/dw-edma-core.c |  1 +
 include/linux/dmaengine.h          | 20 ++++++++++++++++++++
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 6ffd8bd82154..cc64a4679e6f 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1078,6 +1078,7 @@ static int __dma_async_device_channel_register(struct dma_device *device,
 					       struct dma_chan *chan,
 					       const char *name)
 {
+	unsigned int id;
 	int rc;
 
 	chan->local = alloc_percpu(typeof(*chan->local));
@@ -1089,11 +1090,13 @@ static int __dma_async_device_channel_register(struct dma_device *device,
 		goto err_free_local;
 	}
 
-	/*
-	 * When the chan_id is a negative value, we are dynamically adding
-	 * the channel. Otherwise we are static enumerating.
-	 */
-	chan->chan_id = ida_alloc(&device->chan_ida, GFP_KERNEL);
+	if (chan->chan_id & DMA_CHAN_ID_STATIC) {
+		id = chan->chan_id & ~DMA_CHAN_ID_STATIC;
+		chan->chan_id = ida_alloc_range(&device->chan_ida, id, id,
+						GFP_KERNEL);
+	} else {
+		chan->chan_id = ida_alloc(&device->chan_ida, GFP_KERNEL);
+	}
 	if (chan->chan_id < 0) {
 		pr_err("%s: unable to alloc ida for chan: %d\n",
 		       __func__, chan->chan_id);
diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 03b2c2188351..a678c70a78fe 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -988,6 +988,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
 					&dw->chip->dt_region_rd[chan->id];
 
 		vchan_init(&chan->vc, dma);
+		dmaengine_set_static_chan_id(&chan->vc.chan, i);
 
 		dw_edma_core_ch_config(chan);
 	}
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index fe33a20abc61..f669b79d7731 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -369,6 +369,26 @@ struct dma_chan {
 	void *private;
 };
 
+#define DMA_CHAN_ID_STATIC	BIT(30)
+
+/**
+ * dmaengine_set_static_chan_id - request an exact DMA engine channel ID
+ * @chan: DMA channel
+ * @id: channel ID, unique within the DMA device
+ *
+ * Drivers may call this after initializing @chan and before registering its
+ * DMA device. The dmaengine core reserves @id from the device IDA instead of
+ * assigning the next available ID.
+ */
+static inline void dmaengine_set_static_chan_id(struct dma_chan *chan,
+						unsigned int id)
+{
+	if (WARN_ON_ONCE(id >= DMA_CHAN_ID_STATIC))
+		return;
+
+	chan->chan_id = DMA_CHAN_ID_STATIC | id;
+}
+
 /**
  * struct dma_chan_dev - relate sysfs device node to backing channel device
  * @chan: driver channel device
-- 
2.51.0

[PATCH v2 2/3] dmaengine: dw-edma: Configure remote interrupt routing

[Koichiro Den]

An endpoint function can reserve an endpoint-local channel while the RC
programs it through an exposed register window. Such a channel must route
interrupts remotely and ignore them on the endpoint.

Use dma_slave_config to set enum dw_edma_ch_irq_mode on idle channels of a
local eDMA-compatible instance. Synchronizing a remote-routed channel
quiesces the hardware, after which the caller can restore its routing and
release it.

The eDMA quiesce may stop a complete direction. The caller must own every
channel in that direction and stop remote programming first.

Suggested-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
Changes in v2:
  - Rework the channel routing from PCI DMA EPF v7 patches 5 and 6.
    https://lore.kernel.org/r/20260813063757.3131865-6-den@valinux.co.jp/
    https://lore.kernel.org/r/20260813063757.3131865-7-den@valinux.co.jp/
  - Use dma_slave_config instead of private delegation helpers. (Frank)
    https://lore.kernel.org/r/ao2nHoCwfTEEiFSr@SMW015318/

 drivers/dma/dw-edma/dw-edma-core.c | 51 +++++++++++++++++++++++++++---
 include/linux/dma/edma.h           |  6 ++++
 2 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index a678c70a78fe..a8c6bd508fcd 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -177,6 +177,30 @@ dw_edma_get_default_irq_mode(struct dw_edma_chan *chan)
 						  DW_EDMA_CH_IRQ_REMOTE;
 }
 
+static int dw_edma_device_config_irq_mode(struct dw_edma_chan *chan,
+					  struct dma_slave_config *config)
+{
+	enum dw_edma_ch_irq_mode mode;
+
+	if (!(chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) ||
+	    config->peripheral_size != sizeof(mode))
+		return -EINVAL;
+
+	mode = *(enum dw_edma_ch_irq_mode *)config->peripheral_config;
+	if (mode != DW_EDMA_CH_IRQ_LOCAL && mode != DW_EDMA_CH_IRQ_REMOTE)
+		return -EINVAL;
+
+	guard(spinlock_irqsave)(&chan->vc.lock);
+
+	if (chan->configured || chan->status != EDMA_ST_IDLE ||
+	    chan->request != EDMA_REQ_NONE)
+		return -EBUSY;
+
+	chan->irq_mode = mode;
+
+	return 0;
+}
+
 static int dw_edma_device_config(struct dma_chan *dchan,
 				 struct dma_slave_config *config)
 {
@@ -184,6 +208,10 @@ static int dw_edma_device_config(struct dma_chan *dchan,
 	bool cfg_non_ll;
 	int non_ll = 0;
 
+	if (chan->dw->chip->mf != EDMA_MF_HDMA_NATIVE &&
+	    config->peripheral_config)
+		return dw_edma_device_config_irq_mode(chan, config);
+
 	chan->non_ll = false;
 	if (chan->dw->chip->mf == EDMA_MF_HDMA_NATIVE) {
 		if (config->peripheral_config &&
@@ -213,10 +241,6 @@ static int dw_edma_device_config(struct dma_chan *dchan,
 
 		if (cfg_non_ll || non_ll)
 			chan->non_ll = true;
-	} else if (config->peripheral_config) {
-		dev_err(dchan->device->dev,
-			"peripheral config param applicable only for HDMA\n");
-		return -EINVAL;
 	}
 
 	memcpy(&chan->config, config, sizeof(*config));
@@ -893,6 +917,17 @@ static void dw_edma_wait_termination(struct dma_chan *dchan)
 static void dw_edma_device_synchronize(struct dma_chan *dchan)
 {
 	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
+	bool remote;
+
+	scoped_guard(spinlock_irqsave, &chan->vc.lock)
+		remote = chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL &&
+			 chan->irq_mode == DW_EDMA_CH_IRQ_REMOTE;
+
+	if (remote && dw_edma_core_ch_quiesce(chan))
+		dev_warn(chan->dw->chip->dev,
+			 "failed to quiesce remote-routed %s channel %u\n",
+			 chan->dir == EDMA_DIR_WRITE ? "write" : "read",
+			 chan->id);
 
 	dw_edma_wait_termination(dchan);
 	cancel_work_sync(&chan->irq_work);
@@ -903,12 +938,18 @@ static void dw_edma_device_synchronize(struct dma_chan *dchan)
 static void dw_edma_free_chan_resources(struct dma_chan *dchan)
 {
 	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
+	enum dw_edma_ch_irq_mode default_mode =
+			dw_edma_get_default_irq_mode(chan);
 
 	dw_edma_device_terminate_all(dchan);
 	dw_edma_device_synchronize(dchan);
 
-	scoped_guard(spinlock_irqsave, &chan->vc.lock)
+	scoped_guard(spinlock_irqsave, &chan->vc.lock) {
 		chan->configured = false;
+		/* Avoid a redundant write racing with shared-IRQ readers. */
+		if (chan->irq_mode != default_mode)
+			chan->irq_mode = default_mode;
+	}
 
 	vchan_free_chan_resources(&chan->vc);
 }
diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
index 3c8e2ef9dee0..54491c9e4b5e 100644
--- a/include/linux/dma/edma.h
+++ b/include/linux/dma/edma.h
@@ -92,6 +92,12 @@ enum dw_edma_chip_flags {
  * handed over to and driven by the remote side, and the recipe above is
  * applied by the driving instance.
  *
+ * On a local eDMA-compatible instance, clients may pass this enum through
+ * dma_slave_config.peripheral_config to switch an idle, unconfigured channel
+ * between LOCAL and REMOTE routing. Before synchronizing a REMOTE channel,
+ * the client must stop remote programming and own every channel affected by
+ * the hardware quiesce.
+ *
  * HDMA linked-list watermark interrupts have the same LWIE/RWIE guidance. HDMA
  * non-linked-list mode has dedicated local and remote stop/abort interrupt
  * enables.
-- 
2.51.0

Re: [PATCH v2 2/3] dmaengine: dw-edma: Configure remote interrupt routing

[Frank Li]

On Sat, Aug 29, 2026 at 01:36:10AM +0900, Koichiro Den wrote:
> An endpoint function can reserve an endpoint-local channel while the RC
> programs it through an exposed register window. Such a channel must route
> interrupts remotely and ignore them on the endpoint.
>
> Use dma_slave_config to set enum dw_edma_ch_irq_mode on idle channels of a
> local eDMA-compatible instance. Synchronizing a remote-routed channel
> quiesces the hardware, after which the caller can restore its routing and
> release it.
>
> The eDMA quiesce may stop a complete direction. The caller must own every
> channel in that direction and stop remote programming first.
>
> Suggested-by: Frank Li <Frank.Li@nxp.com>
> Signed-off-by: Koichiro Den <den@valinux.co.jp>
> ---
> Changes in v2:
>   - Rework the channel routing from PCI DMA EPF v7 patches 5 and 6.
>     https://lore.kernel.org/r/20260813063757.3131865-6-den@valinux.co.jp/
>     https://lore.kernel.org/r/20260813063757.3131865-7-den@valinux.co.jp/
>   - Use dma_slave_config instead of private delegation helpers. (Frank)
>     https://lore.kernel.org/r/ao2nHoCwfTEEiFSr@SMW015318/
>
>  drivers/dma/dw-edma/dw-edma-core.c | 51 +++++++++++++++++++++++++++---
>  include/linux/dma/edma.h           |  6 ++++
>  2 files changed, 52 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index a678c70a78fe..a8c6bd508fcd 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -177,6 +177,30 @@ dw_edma_get_default_irq_mode(struct dw_edma_chan *chan)
>  						  DW_EDMA_CH_IRQ_REMOTE;
>  }
>
> +static int dw_edma_device_config_irq_mode(struct dw_edma_chan *chan,
> +					  struct dma_slave_config *config)
> +{
> +	enum dw_edma_ch_irq_mode mode;
> +
> +	if (!(chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) ||
> +	    config->peripheral_size != sizeof(mode))
> +		return -EINVAL;
> +
> +	mode = *(enum dw_edma_ch_irq_mode *)config->peripheral_config;

existing code use peripheral_config indicate non_ll mode, is it compatible
with irq mode?

Frank

> +	if (mode != DW_EDMA_CH_IRQ_LOCAL && mode != DW_EDMA_CH_IRQ_REMOTE)
> +		return -EINVAL;
> +
> +	guard(spinlock_irqsave)(&chan->vc.lock);
> +
> +	if (chan->configured || chan->status != EDMA_ST_IDLE ||
> +	    chan->request != EDMA_REQ_NONE)
> +		return -EBUSY;
> +
> +	chan->irq_mode = mode;
> +
> +	return 0;
> +}
> +
>  static int dw_edma_device_config(struct dma_chan *dchan,
>  				 struct dma_slave_config *config)
>  {
> @@ -184,6 +208,10 @@ static int dw_edma_device_config(struct dma_chan *dchan,
>  	bool cfg_non_ll;
>  	int non_ll = 0;
>
> +	if (chan->dw->chip->mf != EDMA_MF_HDMA_NATIVE &&
> +	    config->peripheral_config)
> +		return dw_edma_device_config_irq_mode(chan, config);
> +
>  	chan->non_ll = false;
>  	if (chan->dw->chip->mf == EDMA_MF_HDMA_NATIVE) {
>  		if (config->peripheral_config &&
> @@ -213,10 +241,6 @@ static int dw_edma_device_config(struct dma_chan *dchan,
>
>  		if (cfg_non_ll || non_ll)
>  			chan->non_ll = true;
> -	} else if (config->peripheral_config) {
> -		dev_err(dchan->device->dev,
> -			"peripheral config param applicable only for HDMA\n");
> -		return -EINVAL;
>  	}
>
>  	memcpy(&chan->config, config, sizeof(*config));
> @@ -893,6 +917,17 @@ static void dw_edma_wait_termination(struct dma_chan *dchan)
>  static void dw_edma_device_synchronize(struct dma_chan *dchan)
>  {
>  	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> +	bool remote;
> +
> +	scoped_guard(spinlock_irqsave, &chan->vc.lock)
> +		remote = chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL &&
> +			 chan->irq_mode == DW_EDMA_CH_IRQ_REMOTE;
> +
> +	if (remote && dw_edma_core_ch_quiesce(chan))
> +		dev_warn(chan->dw->chip->dev,
> +			 "failed to quiesce remote-routed %s channel %u\n",
> +			 chan->dir == EDMA_DIR_WRITE ? "write" : "read",
> +			 chan->id);
>
>  	dw_edma_wait_termination(dchan);
>  	cancel_work_sync(&chan->irq_work);
> @@ -903,12 +938,18 @@ static void dw_edma_device_synchronize(struct dma_chan *dchan)
>  static void dw_edma_free_chan_resources(struct dma_chan *dchan)
>  {
>  	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> +	enum dw_edma_ch_irq_mode default_mode =
> +			dw_edma_get_default_irq_mode(chan);
>
>  	dw_edma_device_terminate_all(dchan);
>  	dw_edma_device_synchronize(dchan);
>
> -	scoped_guard(spinlock_irqsave, &chan->vc.lock)
> +	scoped_guard(spinlock_irqsave, &chan->vc.lock) {
>  		chan->configured = false;
> +		/* Avoid a redundant write racing with shared-IRQ readers. */
> +		if (chan->irq_mode != default_mode)
> +			chan->irq_mode = default_mode;
> +	}
>
>  	vchan_free_chan_resources(&chan->vc);
>  }
> diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
> index 3c8e2ef9dee0..54491c9e4b5e 100644
> --- a/include/linux/dma/edma.h
> +++ b/include/linux/dma/edma.h
> @@ -92,6 +92,12 @@ enum dw_edma_chip_flags {
>   * handed over to and driven by the remote side, and the recipe above is
>   * applied by the driving instance.
>   *
> + * On a local eDMA-compatible instance, clients may pass this enum through
> + * dma_slave_config.peripheral_config to switch an idle, unconfigured channel
> + * between LOCAL and REMOTE routing. Before synchronizing a REMOTE channel,
> + * the client must stop remote programming and own every channel affected by
> + * the hardware quiesce.
> + *
>   * HDMA linked-list watermark interrupts have the same LWIE/RWIE guidance. HDMA
>   * non-linked-list mode has dedicated local and remote stop/abort interrupt
>   * enables.
> --
> 2.51.0
>

Re: [PATCH v2 2/3] dmaengine: dw-edma: Configure remote interrupt routing

[Koichiro Den]

On Fri, Aug 28, 2026 at 01:41:57PM -0500, Frank Li wrote:
> On Sat, Aug 29, 2026 at 01:36:10AM +0900, Koichiro Den wrote:
> > An endpoint function can reserve an endpoint-local channel while the RC
> > programs it through an exposed register window. Such a channel must route
> > interrupts remotely and ignore them on the endpoint.
> >
> > Use dma_slave_config to set enum dw_edma_ch_irq_mode on idle channels of a
> > local eDMA-compatible instance. Synchronizing a remote-routed channel
> > quiesces the hardware, after which the caller can restore its routing and
> > release it.
> >
> > The eDMA quiesce may stop a complete direction. The caller must own every
> > channel in that direction and stop remote programming first.
> >
> > Suggested-by: Frank Li <Frank.Li@nxp.com>
> > Signed-off-by: Koichiro Den <den@valinux.co.jp>
> > ---
> > Changes in v2:
> >   - Rework the channel routing from PCI DMA EPF v7 patches 5 and 6.
> >     https://lore.kernel.org/r/20260813063757.3131865-6-den@valinux.co.jp/
> >     https://lore.kernel.org/r/20260813063757.3131865-7-den@valinux.co.jp/
> >   - Use dma_slave_config instead of private delegation helpers. (Frank)
> >     https://lore.kernel.org/r/ao2nHoCwfTEEiFSr@SMW015318/
> >
> >  drivers/dma/dw-edma/dw-edma-core.c | 51 +++++++++++++++++++++++++++---
> >  include/linux/dma/edma.h           |  6 ++++
> >  2 files changed, 52 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> > index a678c70a78fe..a8c6bd508fcd 100644
> > --- a/drivers/dma/dw-edma/dw-edma-core.c
> > +++ b/drivers/dma/dw-edma/dw-edma-core.c
> > @@ -177,6 +177,30 @@ dw_edma_get_default_irq_mode(struct dw_edma_chan *chan)
> >  						  DW_EDMA_CH_IRQ_REMOTE;
> >  }
> >
> > +static int dw_edma_device_config_irq_mode(struct dw_edma_chan *chan,
> > +					  struct dma_slave_config *config)
> > +{
> > +	enum dw_edma_ch_irq_mode mode;
> > +
> > +	if (!(chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) ||
> > +	    config->peripheral_size != sizeof(mode))
> > +		return -EINVAL;
> > +
> > +	mode = *(enum dw_edma_ch_irq_mode *)config->peripheral_config;
> 
> existing code use peripheral_config indicate non_ll mode, is it compatible
> with irq mode?

Yes. dw_edma_device_config() currently distinguishes them by map format.

As a small first step, the remote-channel use introduced by this prep series and
used by the main vNTB series [1] does not cover HDMA. See the cover letter of
[1].

Would you prefer introducing a common config structure at this point?
Requiring every caller to initialize both fields may not be ideal, so perhaps it
could carry a bitmap indicating which fields are valid:

  #define DW_EDMA_CH_CONFIG_NON_LL       BIT(0)
  #define DW_EDMA_CH_CONFIG_IRQ_MODE     BIT(1)

  struct dw_edma_chan_config {
          u32 flags;
          bool non_ll;
          enum dw_edma_ch_irq_mode irq_mode;
  };

What do you think?

[1] https://lore.kernel.org/r/20260828170932.2735807-1-den@valinux.co.jp/

Thanks,
Koichiro

> 
> Frank
> 
> > +	if (mode != DW_EDMA_CH_IRQ_LOCAL && mode != DW_EDMA_CH_IRQ_REMOTE)
> > +		return -EINVAL;
> > +
> > +	guard(spinlock_irqsave)(&chan->vc.lock);
> > +
> > +	if (chan->configured || chan->status != EDMA_ST_IDLE ||
> > +	    chan->request != EDMA_REQ_NONE)
> > +		return -EBUSY;
> > +
> > +	chan->irq_mode = mode;
> > +
> > +	return 0;
> > +}
> > +
> >  static int dw_edma_device_config(struct dma_chan *dchan,
> >  				 struct dma_slave_config *config)
> >  {
> > @@ -184,6 +208,10 @@ static int dw_edma_device_config(struct dma_chan *dchan,
> >  	bool cfg_non_ll;
> >  	int non_ll = 0;
> >
> > +	if (chan->dw->chip->mf != EDMA_MF_HDMA_NATIVE &&
> > +	    config->peripheral_config)
> > +		return dw_edma_device_config_irq_mode(chan, config);
> > +
> >  	chan->non_ll = false;
> >  	if (chan->dw->chip->mf == EDMA_MF_HDMA_NATIVE) {
> >  		if (config->peripheral_config &&
> > @@ -213,10 +241,6 @@ static int dw_edma_device_config(struct dma_chan *dchan,
> >
> >  		if (cfg_non_ll || non_ll)
> >  			chan->non_ll = true;
> > -	} else if (config->peripheral_config) {
> > -		dev_err(dchan->device->dev,
> > -			"peripheral config param applicable only for HDMA\n");
> > -		return -EINVAL;
> >  	}
> >
> >  	memcpy(&chan->config, config, sizeof(*config));
> > @@ -893,6 +917,17 @@ static void dw_edma_wait_termination(struct dma_chan *dchan)
> >  static void dw_edma_device_synchronize(struct dma_chan *dchan)
> >  {
> >  	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> > +	bool remote;
> > +
> > +	scoped_guard(spinlock_irqsave, &chan->vc.lock)
> > +		remote = chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL &&
> > +			 chan->irq_mode == DW_EDMA_CH_IRQ_REMOTE;
> > +
> > +	if (remote && dw_edma_core_ch_quiesce(chan))
> > +		dev_warn(chan->dw->chip->dev,
> > +			 "failed to quiesce remote-routed %s channel %u\n",
> > +			 chan->dir == EDMA_DIR_WRITE ? "write" : "read",
> > +			 chan->id);
> >
> >  	dw_edma_wait_termination(dchan);
> >  	cancel_work_sync(&chan->irq_work);
> > @@ -903,12 +938,18 @@ static void dw_edma_device_synchronize(struct dma_chan *dchan)
> >  static void dw_edma_free_chan_resources(struct dma_chan *dchan)
> >  {
> >  	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> > +	enum dw_edma_ch_irq_mode default_mode =
> > +			dw_edma_get_default_irq_mode(chan);
> >
> >  	dw_edma_device_terminate_all(dchan);
> >  	dw_edma_device_synchronize(dchan);
> >
> > -	scoped_guard(spinlock_irqsave, &chan->vc.lock)
> > +	scoped_guard(spinlock_irqsave, &chan->vc.lock) {
> >  		chan->configured = false;
> > +		/* Avoid a redundant write racing with shared-IRQ readers. */
> > +		if (chan->irq_mode != default_mode)
> > +			chan->irq_mode = default_mode;
> > +	}
> >
> >  	vchan_free_chan_resources(&chan->vc);
> >  }
> > diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
> > index 3c8e2ef9dee0..54491c9e4b5e 100644
> > --- a/include/linux/dma/edma.h
> > +++ b/include/linux/dma/edma.h
> > @@ -92,6 +92,12 @@ enum dw_edma_chip_flags {
> >   * handed over to and driven by the remote side, and the recipe above is
> >   * applied by the driving instance.
> >   *
> > + * On a local eDMA-compatible instance, clients may pass this enum through
> > + * dma_slave_config.peripheral_config to switch an idle, unconfigured channel
> > + * between LOCAL and REMOTE routing. Before synchronizing a REMOTE channel,
> > + * the client must stop remote programming and own every channel affected by
> > + * the hardware quiesce.
> > + *
> >   * HDMA linked-list watermark interrupts have the same LWIE/RWIE guidance. HDMA
> >   * non-linked-list mode has dedicated local and remote stop/abort interrupt
> >   * enables.
> > --
> > 2.51.0
> >

Re: [PATCH v2 2/3] dmaengine: dw-edma: Configure remote interrupt routing

[Frank Li]

On Sun, Aug 30, 2026 at 03:13:23AM +0900, Koichiro Den wrote:
> On Fri, Aug 28, 2026 at 01:41:57PM -0500, Frank Li wrote:
> > On Sat, Aug 29, 2026 at 01:36:10AM +0900, Koichiro Den wrote:
> > > An endpoint function can reserve an endpoint-local channel while the RC
> > > programs it through an exposed register window. Such a channel must route
> > > interrupts remotely and ignore them on the endpoint.
> > >
> > > Use dma_slave_config to set enum dw_edma_ch_irq_mode on idle channels of a
> > > local eDMA-compatible instance. Synchronizing a remote-routed channel
> > > quiesces the hardware, after which the caller can restore its routing and
> > > release it.
> > >
> > > The eDMA quiesce may stop a complete direction. The caller must own every
> > > channel in that direction and stop remote programming first.
> > >
> > > Suggested-by: Frank Li <Frank.Li@nxp.com>
> > > Signed-off-by: Koichiro Den <den@valinux.co.jp>
> > > ---
> > > Changes in v2:
> > >   - Rework the channel routing from PCI DMA EPF v7 patches 5 and 6.
> > >     https://lore.kernel.org/r/20260813063757.3131865-6-den@valinux.co.jp/
> > >     https://lore.kernel.org/r/20260813063757.3131865-7-den@valinux.co.jp/
> > >   - Use dma_slave_config instead of private delegation helpers. (Frank)
> > >     https://lore.kernel.org/r/ao2nHoCwfTEEiFSr@SMW015318/
> > >
> > >  drivers/dma/dw-edma/dw-edma-core.c | 51 +++++++++++++++++++++++++++---
> > >  include/linux/dma/edma.h           |  6 ++++
> > >  2 files changed, 52 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> > > index a678c70a78fe..a8c6bd508fcd 100644
> > > --- a/drivers/dma/dw-edma/dw-edma-core.c
> > > +++ b/drivers/dma/dw-edma/dw-edma-core.c
> > > @@ -177,6 +177,30 @@ dw_edma_get_default_irq_mode(struct dw_edma_chan *chan)
> > >  						  DW_EDMA_CH_IRQ_REMOTE;
> > >  }
> > >
> > > +static int dw_edma_device_config_irq_mode(struct dw_edma_chan *chan,
> > > +					  struct dma_slave_config *config)
> > > +{
> > > +	enum dw_edma_ch_irq_mode mode;
> > > +
> > > +	if (!(chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL) ||
> > > +	    config->peripheral_size != sizeof(mode))
> > > +		return -EINVAL;
> > > +
> > > +	mode = *(enum dw_edma_ch_irq_mode *)config->peripheral_config;
> >
> > existing code use peripheral_config indicate non_ll mode, is it compatible
> > with irq mode?
>
> Yes. dw_edma_device_config() currently distinguishes them by map format.
>
> As a small first step, the remote-channel use introduced by this prep series and
> used by the main vNTB series [1] does not cover HDMA. See the cover letter of
> [1].
>
> Would you prefer introducing a common config structure at this point?
> Requiring every caller to initialize both fields may not be ideal, so perhaps it
> could carry a bitmap indicating which fields are valid:
>
>   #define DW_EDMA_CH_CONFIG_NON_LL       BIT(0)
>   #define DW_EDMA_CH_CONFIG_IRQ_MODE     BIT(1)
>
>   struct dw_edma_chan_config {
>           u32 flags;
>           bool non_ll;
>           enum dw_edma_ch_irq_mode irq_mode;
>   };
>
> What do you think?

Okay, it avoid need init all field.

Frank

>
> [1] https://lore.kernel.org/r/20260828170932.2735807-1-den@valinux.co.jp/
>
> Thanks,
> Koichiro
>
> >
> > Frank
> >
> > > +	if (mode != DW_EDMA_CH_IRQ_LOCAL && mode != DW_EDMA_CH_IRQ_REMOTE)
> > > +		return -EINVAL;
> > > +
> > > +	guard(spinlock_irqsave)(&chan->vc.lock);
> > > +
> > > +	if (chan->configured || chan->status != EDMA_ST_IDLE ||
> > > +	    chan->request != EDMA_REQ_NONE)
> > > +		return -EBUSY;
> > > +
> > > +	chan->irq_mode = mode;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > >  static int dw_edma_device_config(struct dma_chan *dchan,
> > >  				 struct dma_slave_config *config)
> > >  {
> > > @@ -184,6 +208,10 @@ static int dw_edma_device_config(struct dma_chan *dchan,
> > >  	bool cfg_non_ll;
> > >  	int non_ll = 0;
> > >
> > > +	if (chan->dw->chip->mf != EDMA_MF_HDMA_NATIVE &&
> > > +	    config->peripheral_config)
> > > +		return dw_edma_device_config_irq_mode(chan, config);
> > > +
> > >  	chan->non_ll = false;
> > >  	if (chan->dw->chip->mf == EDMA_MF_HDMA_NATIVE) {
> > >  		if (config->peripheral_config &&
> > > @@ -213,10 +241,6 @@ static int dw_edma_device_config(struct dma_chan *dchan,
> > >
> > >  		if (cfg_non_ll || non_ll)
> > >  			chan->non_ll = true;
> > > -	} else if (config->peripheral_config) {
> > > -		dev_err(dchan->device->dev,
> > > -			"peripheral config param applicable only for HDMA\n");
> > > -		return -EINVAL;
> > >  	}
> > >
> > >  	memcpy(&chan->config, config, sizeof(*config));
> > > @@ -893,6 +917,17 @@ static void dw_edma_wait_termination(struct dma_chan *dchan)
> > >  static void dw_edma_device_synchronize(struct dma_chan *dchan)
> > >  {
> > >  	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> > > +	bool remote;
> > > +
> > > +	scoped_guard(spinlock_irqsave, &chan->vc.lock)
> > > +		remote = chan->dw->chip->flags & DW_EDMA_CHIP_LOCAL &&
> > > +			 chan->irq_mode == DW_EDMA_CH_IRQ_REMOTE;
> > > +
> > > +	if (remote && dw_edma_core_ch_quiesce(chan))
> > > +		dev_warn(chan->dw->chip->dev,
> > > +			 "failed to quiesce remote-routed %s channel %u\n",
> > > +			 chan->dir == EDMA_DIR_WRITE ? "write" : "read",
> > > +			 chan->id);
> > >
> > >  	dw_edma_wait_termination(dchan);
> > >  	cancel_work_sync(&chan->irq_work);
> > > @@ -903,12 +938,18 @@ static void dw_edma_device_synchronize(struct dma_chan *dchan)
> > >  static void dw_edma_free_chan_resources(struct dma_chan *dchan)
> > >  {
> > >  	struct dw_edma_chan *chan = dchan2dw_edma_chan(dchan);
> > > +	enum dw_edma_ch_irq_mode default_mode =
> > > +			dw_edma_get_default_irq_mode(chan);
> > >
> > >  	dw_edma_device_terminate_all(dchan);
> > >  	dw_edma_device_synchronize(dchan);
> > >
> > > -	scoped_guard(spinlock_irqsave, &chan->vc.lock)
> > > +	scoped_guard(spinlock_irqsave, &chan->vc.lock) {
> > >  		chan->configured = false;
> > > +		/* Avoid a redundant write racing with shared-IRQ readers. */
> > > +		if (chan->irq_mode != default_mode)
> > > +			chan->irq_mode = default_mode;
> > > +	}
> > >
> > >  	vchan_free_chan_resources(&chan->vc);
> > >  }
> > > diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
> > > index 3c8e2ef9dee0..54491c9e4b5e 100644
> > > --- a/include/linux/dma/edma.h
> > > +++ b/include/linux/dma/edma.h
> > > @@ -92,6 +92,12 @@ enum dw_edma_chip_flags {
> > >   * handed over to and driven by the remote side, and the recipe above is
> > >   * applied by the driving instance.
> > >   *
> > > + * On a local eDMA-compatible instance, clients may pass this enum through
> > > + * dma_slave_config.peripheral_config to switch an idle, unconfigured channel
> > > + * between LOCAL and REMOTE routing. Before synchronizing a REMOTE channel,
> > > + * the client must stop remote programming and own every channel affected by
> > > + * the hardware quiesce.
> > > + *
> > >   * HDMA linked-list watermark interrupts have the same LWIE/RWIE guidance. HDMA
> > >   * non-linked-list mode has dedicated local and remote stop/abort interrupt
> > >   * enables.
> > > --
> > > 2.51.0
> > >

[PATCH v2 3/3] dmaengine: dw-edma: Account for the MSI vector offset

[Koichiro Den]

get_cached_msi_msg() returns the base message shared by a multi-MSI
descriptor. dw-edma currently derives per-channel data from its local IRQ
index and does not adjust a common IRQ at all. Both assume eDMA starts at
the descriptor's first vector.

That is not true when eDMA receives a tail subset. Compose each message
from the IRQ offset relative to the descriptor base in both paths.

While at it, avoid reading PCI MSI attributes from descriptors owned by
non-PCI devices.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
Changes in v2:
  - Rework v1 patch 5 for an MSI allocation shared with vNTB.
    https://lore.kernel.org/r/20260312165005.1148676-6-den@valinux.co.jp/

 drivers/dma/dw-edma/dw-edma-core.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index a8c6bd508fcd..6af8a414e4a2 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/pci.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
@@ -1075,12 +1076,23 @@ static inline void dw_edma_dec_irq_alloc(int *nr_irqs, u32 *alloc, u16 cnt)
 	}
 }
 
+static void dw_edma_compose_msi(int irq, struct msi_msg *msi)
+{
+	struct msi_desc *desc = irq_get_msi_desc(irq);
+
+	if (!desc)
+		return;
+
+	get_cached_msi_msg(irq, msi);
+	if (dev_is_pci(desc->dev) && !desc->pci.msi_attrib.is_msix)
+		msi->data += irq - desc->irq;
+}
+
 static int dw_edma_irq_request(struct dw_edma *dw,
 			       u32 *wr_alloc, u32 *rd_alloc)
 {
 	struct dw_edma_chip *chip = dw->chip;
 	struct device *dev = dw->chip->dev;
-	struct msi_desc *msi_desc;
 	int i, err = 0;
 	u32 ch_cnt;
 	int irq;
@@ -1105,8 +1117,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
 			return err;
 		}
 
-		if (irq_get_msi_desc(irq))
-			get_cached_msi_msg(irq, &dw->irq[0].msi);
+		dw_edma_compose_msi(irq, &dw->irq[0].msi);
 
 		dw->nr_irqs = 1;
 	} else {
@@ -1129,12 +1140,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
 					  &dw->irq[i]);
 			if (err)
 				goto err_irq_free;
-			msi_desc = irq_get_msi_desc(irq);
-			if (msi_desc) {
-				get_cached_msi_msg(irq, &dw->irq[i].msi);
-				if (!msi_desc->pci.msi_attrib.is_msix)
-					dw->irq[i].msi.data = dw->irq[0].msi.data + i;
-			}
+			dw_edma_compose_msi(irq, &dw->irq[i].msi);
 		}
 
 		dw->nr_irqs = i;
-- 
2.51.0

Re: [PATCH v2 3/3] dmaengine: dw-edma: Account for the MSI vector offset

[Frank Li]

On Sat, Aug 29, 2026 at 01:36:11AM +0900, Koichiro Den wrote:
> get_cached_msi_msg() returns the base message shared by a multi-MSI
> descriptor. dw-edma currently derives per-channel data from its local IRQ
> index and does not adjust a common IRQ at all. Both assume eDMA starts at
> the descriptor's first vector.
>
> That is not true when eDMA receives a tail subset. Compose each message
> from the IRQ offset relative to the descriptor base in both paths.
>
> While at it, avoid reading PCI MSI attributes from descriptors owned by
> non-PCI devices.
>
> Signed-off-by: Koichiro Den <den@valinux.co.jp>
> ---
> Changes in v2:
>   - Rework v1 patch 5 for an MSI allocation shared with vNTB.
>     https://lore.kernel.org/r/20260312165005.1148676-6-den@valinux.co.jp/
>
>  drivers/dma/dw-edma/dw-edma-core.c | 24 +++++++++++++++---------
>  1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index a8c6bd508fcd..6af8a414e4a2 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -7,6 +7,7 @@
>   */
>
>  #include <linux/module.h>
> +#include <linux/pci.h>
>  #include <linux/delay.h>
>  #include <linux/device.h>
>  #include <linux/kernel.h>
> @@ -1075,12 +1076,23 @@ static inline void dw_edma_dec_irq_alloc(int *nr_irqs, u32 *alloc, u16 cnt)
>  	}
>  }
>
> +static void dw_edma_compose_msi(int irq, struct msi_msg *msi)
> +{
> +	struct msi_desc *desc = irq_get_msi_desc(irq);
> +
> +	if (!desc)
> +		return;
> +
> +	get_cached_msi_msg(irq, msi);
> +	if (dev_is_pci(desc->dev) && !desc->pci.msi_attrib.is_msix)
> +		msi->data += irq - desc->irq;
> +}
> +
>  static int dw_edma_irq_request(struct dw_edma *dw,
>  			       u32 *wr_alloc, u32 *rd_alloc)
>  {
>  	struct dw_edma_chip *chip = dw->chip;
>  	struct device *dev = dw->chip->dev;
> -	struct msi_desc *msi_desc;
>  	int i, err = 0;
>  	u32 ch_cnt;
>  	int irq;
> @@ -1105,8 +1117,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
>  			return err;
>  		}
>
> -		if (irq_get_msi_desc(irq))
> -			get_cached_msi_msg(irq, &dw->irq[0].msi);
> +		dw_edma_compose_msi(irq, &dw->irq[0].msi);

where this function? I missed dependence?

Frank
>
>  		dw->nr_irqs = 1;
>  	} else {
> @@ -1129,12 +1140,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
>  					  &dw->irq[i]);
>  			if (err)
>  				goto err_irq_free;
> -			msi_desc = irq_get_msi_desc(irq);
> -			if (msi_desc) {
> -				get_cached_msi_msg(irq, &dw->irq[i].msi);
> -				if (!msi_desc->pci.msi_attrib.is_msix)
> -					dw->irq[i].msi.data = dw->irq[0].msi.data + i;
> -			}
> +			dw_edma_compose_msi(irq, &dw->irq[i].msi);
>  		}
>
>  		dw->nr_irqs = i;
> --
> 2.51.0
>

Re: [PATCH v2 3/3] dmaengine: dw-edma: Account for the MSI vector offset

[Koichiro Den]

On Fri, Aug 28, 2026 at 01:46:17PM -0500, Frank Li wrote:
> On Sat, Aug 29, 2026 at 01:36:11AM +0900, Koichiro Den wrote:
> > get_cached_msi_msg() returns the base message shared by a multi-MSI
> > descriptor. dw-edma currently derives per-channel data from its local IRQ
> > index and does not adjust a common IRQ at all. Both assume eDMA starts at
> > the descriptor's first vector.
> >
> > That is not true when eDMA receives a tail subset. Compose each message
> > from the IRQ offset relative to the descriptor base in both paths.
> >
> > While at it, avoid reading PCI MSI attributes from descriptors owned by
> > non-PCI devices.
> >
> > Signed-off-by: Koichiro Den <den@valinux.co.jp>
> > ---
> > Changes in v2:
> >   - Rework v1 patch 5 for an MSI allocation shared with vNTB.
> >     https://lore.kernel.org/r/20260312165005.1148676-6-den@valinux.co.jp/
> >
> >  drivers/dma/dw-edma/dw-edma-core.c | 24 +++++++++++++++---------
> >  1 file changed, 15 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> > index a8c6bd508fcd..6af8a414e4a2 100644
> > --- a/drivers/dma/dw-edma/dw-edma-core.c
> > +++ b/drivers/dma/dw-edma/dw-edma-core.c
> > @@ -7,6 +7,7 @@
> >   */
> >
> >  #include <linux/module.h>
> > +#include <linux/pci.h>
> >  #include <linux/delay.h>
> >  #include <linux/device.h>
> >  #include <linux/kernel.h>
> > @@ -1075,12 +1076,23 @@ static inline void dw_edma_dec_irq_alloc(int *nr_irqs, u32 *alloc, u16 cnt)
> >  	}
> >  }
> >
> > +static void dw_edma_compose_msi(int irq, struct msi_msg *msi)

^(A)

> > +{
> > +	struct msi_desc *desc = irq_get_msi_desc(irq);
> > +
> > +	if (!desc)
> > +		return;
> > +
> > +	get_cached_msi_msg(irq, msi);
> > +	if (dev_is_pci(desc->dev) && !desc->pci.msi_attrib.is_msix)
> > +		msi->data += irq - desc->irq;
> > +}
> > +
> >  static int dw_edma_irq_request(struct dw_edma *dw,
> >  			       u32 *wr_alloc, u32 *rd_alloc)
> >  {
> >  	struct dw_edma_chip *chip = dw->chip;
> >  	struct device *dev = dw->chip->dev;
> > -	struct msi_desc *msi_desc;
> >  	int i, err = 0;
> >  	u32 ch_cnt;
> >  	int irq;
> > @@ -1105,8 +1117,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
> >  			return err;
> >  		}
> >
> > -		if (irq_get_msi_desc(irq))
> > -			get_cached_msi_msg(irq, &dw->irq[0].msi);
> > +		dw_edma_compose_msi(irq, &dw->irq[0].msi);
> 
> where this function? I missed dependence?

It's defined just above in this patch, as shown in (A).

Best regards,
Koichiro

> 
> Frank
> >
> >  		dw->nr_irqs = 1;
> >  	} else {
> > @@ -1129,12 +1140,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
> >  					  &dw->irq[i]);
> >  			if (err)
> >  				goto err_irq_free;
> > -			msi_desc = irq_get_msi_desc(irq);
> > -			if (msi_desc) {
> > -				get_cached_msi_msg(irq, &dw->irq[i].msi);
> > -				if (!msi_desc->pci.msi_attrib.is_msix)
> > -					dw->irq[i].msi.data = dw->irq[0].msi.data + i;
> > -			}
> > +			dw_edma_compose_msi(irq, &dw->irq[i].msi);
> >  		}
> >
> >  		dw->nr_irqs = i;
> > --
> > 2.51.0
> >

Re: [PATCH v2 3/3] dmaengine: dw-edma: Account for the MSI vector offset

[Frank Li]

On Sat, Aug 29, 2026 at 01:36:11AM +0900, Koichiro Den wrote:
> get_cached_msi_msg() returns the base message shared by a multi-MSI
> descriptor. dw-edma currently derives per-channel data from its local IRQ
> index and does not adjust a common IRQ at all. Both assume eDMA starts at
> the descriptor's first vector.
>
> That is not true when eDMA receives a tail subset. Compose each message
> from the IRQ offset relative to the descriptor base in both paths.
>
> While at it, avoid reading PCI MSI attributes from descriptors owned by
> non-PCI devices.
>
> Signed-off-by: Koichiro Den <den@valinux.co.jp>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

> Changes in v2:
>   - Rework v1 patch 5 for an MSI allocation shared with vNTB.
>     https://lore.kernel.org/r/20260312165005.1148676-6-den@valinux.co.jp/
>
>  drivers/dma/dw-edma/dw-edma-core.c | 24 +++++++++++++++---------
>  1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index a8c6bd508fcd..6af8a414e4a2 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -7,6 +7,7 @@
>   */
>
>  #include <linux/module.h>
> +#include <linux/pci.h>
>  #include <linux/delay.h>
>  #include <linux/device.h>
>  #include <linux/kernel.h>
> @@ -1075,12 +1076,23 @@ static inline void dw_edma_dec_irq_alloc(int *nr_irqs, u32 *alloc, u16 cnt)
>  	}
>  }
>
> +static void dw_edma_compose_msi(int irq, struct msi_msg *msi)
> +{
> +	struct msi_desc *desc = irq_get_msi_desc(irq);
> +
> +	if (!desc)
> +		return;
> +
> +	get_cached_msi_msg(irq, msi);
> +	if (dev_is_pci(desc->dev) && !desc->pci.msi_attrib.is_msix)
> +		msi->data += irq - desc->irq;
> +}
> +
>  static int dw_edma_irq_request(struct dw_edma *dw,
>  			       u32 *wr_alloc, u32 *rd_alloc)
>  {
>  	struct dw_edma_chip *chip = dw->chip;
>  	struct device *dev = dw->chip->dev;
> -	struct msi_desc *msi_desc;
>  	int i, err = 0;
>  	u32 ch_cnt;
>  	int irq;
> @@ -1105,8 +1117,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
>  			return err;
>  		}
>
> -		if (irq_get_msi_desc(irq))
> -			get_cached_msi_msg(irq, &dw->irq[0].msi);
> +		dw_edma_compose_msi(irq, &dw->irq[0].msi);
>
>  		dw->nr_irqs = 1;
>  	} else {
> @@ -1129,12 +1140,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
>  					  &dw->irq[i]);
>  			if (err)
>  				goto err_irq_free;
> -			msi_desc = irq_get_msi_desc(irq);
> -			if (msi_desc) {
> -				get_cached_msi_msg(irq, &dw->irq[i].msi);
> -				if (!msi_desc->pci.msi_attrib.is_msix)
> -					dw->irq[i].msi.data = dw->irq[0].msi.data + i;
> -			}
> +			dw_edma_compose_msi(irq, &dw->irq[i].msi);
>  		}
>
>  		dw->nr_irqs = i;
> --
> 2.51.0
>