[v4] dmaengine, PCI: endpoint: Enable remote use of integrated DesignWare eDMA

[PATCH v4 3/9] dmaengine: dw-edma: Export per-channel IRQ and doorbell register offset

Posted by Koichiro Den 2 days, 23 hours ago

Endpoint controller drivers may need to expose or consume eDMA-related
resources (e.g. for remote programming or doorbell/self-tests). For
that, consumers need a stable way to discover the Linux IRQ used by a
given eDMA channel/vector and a register offset suitable for interrupt
emulation.

Record each channel's IRQ-vector index and store the requested Linux IRQ
number. Add a core callback .ch_info() to provide core-specific metadata
and implement it for v0.

Export dw_edma_chan_info() so that platform drivers can retrieve:
  - per-channel device name
  - Linux IRQ number for the channel's interrupt vector
  - offset of the register used as an emulated-interrupt doorbell within
    the eDMA register window.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
 drivers/dma/dw-edma/dw-edma-core.c    | 31 +++++++++++++++++++++++++++
 drivers/dma/dw-edma/dw-edma-core.h    | 14 ++++++++++++
 drivers/dma/dw-edma/dw-edma-v0-core.c |  7 ++++++
 include/linux/dma/edma.h              | 20 +++++++++++++++++
 4 files changed, 72 insertions(+)

diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index dd01a9aa8ad8..147a5466e4e7 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -842,6 +842,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
 		else
 			pos = wr_alloc + chan->id % rd_alloc;
 
+		chan->irq_idx = pos;
 		irq = &dw->irq[pos];
 
 		if (chan->dir == EDMA_DIR_WRITE)
@@ -947,6 +948,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
 		if (irq_get_msi_desc(irq))
 			get_cached_msi_msg(irq, &dw->irq[0].msi);
 
+		dw->irq[0].irq = irq;
 		dw->nr_irqs = 1;
 	} else {
 		/* Distribute IRQs equally among all channels */
@@ -973,6 +975,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
 
 			if (irq_get_msi_desc(irq))
 				get_cached_msi_msg(irq, &dw->irq[i].msi);
+			dw->irq[i].irq = irq;
 		}
 
 		dw->nr_irqs = i;
@@ -1098,6 +1101,34 @@ int dw_edma_remove(struct dw_edma_chip *chip)
 }
 EXPORT_SYMBOL_GPL(dw_edma_remove);
 
+int dw_edma_chan_info(struct dw_edma_chip *chip, unsigned int ch_idx,
+		      struct dw_edma_chan_info *info)
+{
+	struct dw_edma *dw = chip->dw;
+	struct dw_edma_chan *chan;
+	struct dma_chan *dchan;
+	u32 ch_cnt;
+	int ret;
+
+	if (!chip || !info || !dw)
+		return -EINVAL;
+
+	ch_cnt = dw->wr_ch_cnt + dw->rd_ch_cnt;
+	if (ch_idx >= ch_cnt)
+		return -EINVAL;
+
+	chan = &dw->chan[ch_idx];
+	dchan = &chan->vc.chan;
+
+	ret = dw_edma_core_ch_info(dw, chan, info);
+	if (ret)
+		return ret;
+
+	info->irq = dw->irq[chan->irq_idx].irq;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_edma_chan_info);
+
 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("Synopsys DesignWare eDMA controller core driver");
 MODULE_AUTHOR("Gustavo Pimentel <gustavo.pimentel@synopsys.com>");
diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
index abc97e375484..e92891ed5536 100644
--- a/drivers/dma/dw-edma/dw-edma-core.h
+++ b/drivers/dma/dw-edma/dw-edma-core.h
@@ -82,6 +82,7 @@ struct dw_edma_chan {
 	struct msi_msg			msi;
 
 	enum dw_edma_ch_irq_mode	irq_mode;
+	u32				irq_idx;
 
 	enum dw_edma_request		request;
 	enum dw_edma_status		status;
@@ -95,6 +96,7 @@ struct dw_edma_irq {
 	u32				wr_mask;
 	u32				rd_mask;
 	struct dw_edma			*dw;
+	int				irq;
 };
 
 struct dw_edma {
@@ -129,6 +131,7 @@ struct dw_edma_core_ops {
 	void (*ch_config)(struct dw_edma_chan *chan);
 	void (*debugfs_on)(struct dw_edma *dw);
 	void (*ack_selfirq)(struct dw_edma *dw);
+	void (*ch_info)(struct dw_edma_chan *chan, struct dw_edma_chan_info *info);
 };
 
 struct dw_edma_sg {
@@ -219,6 +222,17 @@ int dw_edma_core_ack_selfirq(struct dw_edma *dw)
 	return 0;
 }
 
+static inline
+int dw_edma_core_ch_info(struct dw_edma *dw, struct dw_edma_chan *chan,
+			 struct dw_edma_chan_info *info)
+{
+	if (!dw->core->ch_info)
+		return -EOPNOTSUPP;
+
+	dw->core->ch_info(chan, info);
+	return 0;
+}
+
 static inline
 bool dw_edma_core_ch_ignore_irq(struct dw_edma_chan *chan)
 {
diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
index 68e0d088570d..9c7908a76fff 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
@@ -529,6 +529,12 @@ static void dw_edma_v0_core_ack_selfirq(struct dw_edma *dw)
 	SET_BOTH_32(dw, int_clear, 0);
 }
 
+static void dw_edma_v0_core_ch_info(struct dw_edma_chan *chan,
+				    struct dw_edma_chan_info *info)
+{
+	info->db_offset = offsetof(struct dw_edma_v0_regs, rd_int_status);
+}
+
 static const struct dw_edma_core_ops dw_edma_v0_core = {
 	.off = dw_edma_v0_core_off,
 	.ch_count = dw_edma_v0_core_ch_count,
@@ -538,6 +544,7 @@ static const struct dw_edma_core_ops dw_edma_v0_core = {
 	.ch_config = dw_edma_v0_core_ch_config,
 	.debugfs_on = dw_edma_v0_core_debugfs_on,
 	.ack_selfirq = dw_edma_v0_core_ack_selfirq,
+	.ch_info = dw_edma_v0_core_ch_info,
 };
 
 void dw_edma_v0_core_register(struct dw_edma *dw)
diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
index 53b31a974331..9fd78dc313e5 100644
--- a/include/linux/dma/edma.h
+++ b/include/linux/dma/edma.h
@@ -129,10 +129,23 @@ struct dw_edma_chip {
 	struct dw_edma		*dw;
 };
 
+/**
+ * struct dw_edma_chan_info - DW eDMA channel metadata
+ * @irq:	Linux IRQ number used by this channel's interrupt vector
+ * @db_offset:	offset within the eDMA register window that can be used as
+ *		an interrupt-emulation doorbell for this channel
+ */
+struct dw_edma_chan_info {
+	int			irq;
+	resource_size_t		db_offset;
+};
+
 /* Export to the platform drivers */
 #if IS_REACHABLE(CONFIG_DW_EDMA)
 int dw_edma_probe(struct dw_edma_chip *chip);
 int dw_edma_remove(struct dw_edma_chip *chip);
+int dw_edma_chan_info(struct dw_edma_chip *chip, unsigned int ch_idx,
+		      struct dw_edma_chan_info *info);
 #else
 static inline int dw_edma_probe(struct dw_edma_chip *chip)
 {
@@ -143,6 +156,13 @@ static inline int dw_edma_remove(struct dw_edma_chip *chip)
 {
 	return 0;
 }
+
+static inline int dw_edma_chan_info(struct dw_edma_chip *chip,
+				    unsigned int ch_idx,
+				    struct dw_edma_chan_info *info)
+{
+	return -ENODEV;
+}
 #endif /* CONFIG_DW_EDMA */
 
 #endif /* _DW_EDMA_H */
-- 
2.51.0

Re: [PATCH v4 3/9] dmaengine: dw-edma: Export per-channel IRQ and doorbell register offset

Posted by kernel test robot 1 day, 7 hours ago

Hi Koichiro,

kernel test robot noticed the following build warnings:

[auto build test WARNING on pci/next]
[also build test WARNING on pci/for-linus linus/master v6.19-rc8 next-20260205]
[cannot apply to vkoul-dmaengine/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Koichiro-Den/dmaengine-dw-edma-Add-per-channel-interrupt-routing-control/20260207-013042
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20260206172646.1556847-4-den%40valinux.co.jp
patch subject: [PATCH v4 3/9] dmaengine: dw-edma: Export per-channel IRQ and doorbell register offset
config: arc-randconfig-002-20260208 (https://download.01.org/0day-ci/archive/20260208/202602081640.ChGzNbe8-lkp@intel.com/config)
compiler: arc-linux-gcc (GCC) 12.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260208/202602081640.ChGzNbe8-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202602081640.ChGzNbe8-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/dma/dw-edma/dw-edma-core.c: In function 'dw_edma_chan_info':
>> drivers/dma/dw-edma/dw-edma-core.c:1109:26: warning: variable 'dchan' set but not used [-Wunused-but-set-variable]
    1109 |         struct dma_chan *dchan;
         |                          ^~~~~

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for CAN_DEV
   Depends on [n]: NETDEVICES [=n] && CAN [=y]
   Selected by [y]:
   - CAN [=y] && NET [=y]


vim +/dchan +1109 drivers/dma/dw-edma/dw-edma-core.c

  1103	
  1104	int dw_edma_chan_info(struct dw_edma_chip *chip, unsigned int ch_idx,
  1105			      struct dw_edma_chan_info *info)
  1106	{
  1107		struct dw_edma *dw = chip->dw;
  1108		struct dw_edma_chan *chan;
> 1109		struct dma_chan *dchan;
  1110		u32 ch_cnt;
  1111		int ret;
  1112	
  1113		if (!chip || !info || !dw)
  1114			return -EINVAL;
  1115	
  1116		ch_cnt = dw->wr_ch_cnt + dw->rd_ch_cnt;
  1117		if (ch_idx >= ch_cnt)
  1118			return -EINVAL;
  1119	
  1120		chan = &dw->chan[ch_idx];
  1121		dchan = &chan->vc.chan;
  1122	
  1123		ret = dw_edma_core_ch_info(dw, chan, info);
  1124		if (ret)
  1125			return ret;
  1126	
  1127		info->irq = dw->irq[chan->irq_idx].irq;
  1128		return 0;
  1129	}
  1130	EXPORT_SYMBOL_GPL(dw_edma_chan_info);
  1131	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v4 3/9] dmaengine: dw-edma: Export per-channel IRQ and doorbell register offset

Posted by Frank Li 2 days, 22 hours ago

On Sat, Feb 07, 2026 at 02:26:40AM +0900, Koichiro Den wrote:
> Endpoint controller drivers may need to expose or consume eDMA-related
> resources (e.g. for remote programming or doorbell/self-tests). For
> that, consumers need a stable way to discover the Linux IRQ used by a
> given eDMA channel/vector and a register offset suitable for interrupt
> emulation.
>
> Record each channel's IRQ-vector index and store the requested Linux IRQ
> number. Add a core callback .ch_info() to provide core-specific metadata
> and implement it for v0.
>
> Export dw_edma_chan_info() so that platform drivers can retrieve:
>   - per-channel device name
>   - Linux IRQ number for the channel's interrupt vector
>   - offset of the register used as an emulated-interrupt doorbell within
>     the eDMA register window.
>
> Signed-off-by: Koichiro Den <den@valinux.co.jp>
> ---
>  drivers/dma/dw-edma/dw-edma-core.c    | 31 +++++++++++++++++++++++++++
>  drivers/dma/dw-edma/dw-edma-core.h    | 14 ++++++++++++
>  drivers/dma/dw-edma/dw-edma-v0-core.c |  7 ++++++
>  include/linux/dma/edma.h              | 20 +++++++++++++++++
>  4 files changed, 72 insertions(+)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index dd01a9aa8ad8..147a5466e4e7 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -842,6 +842,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
>  		else
>  			pos = wr_alloc + chan->id % rd_alloc;
>
> +		chan->irq_idx = pos;
>  		irq = &dw->irq[pos];
>
>  		if (chan->dir == EDMA_DIR_WRITE)
> @@ -947,6 +948,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
>  		if (irq_get_msi_desc(irq))
>  			get_cached_msi_msg(irq, &dw->irq[0].msi);
>
> +		dw->irq[0].irq = irq;
>  		dw->nr_irqs = 1;
>  	} else {
>  		/* Distribute IRQs equally among all channels */
> @@ -973,6 +975,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
>
>  			if (irq_get_msi_desc(irq))
>  				get_cached_msi_msg(irq, &dw->irq[i].msi);
> +			dw->irq[i].irq = irq;
>  		}
>
>  		dw->nr_irqs = i;
> @@ -1098,6 +1101,34 @@ int dw_edma_remove(struct dw_edma_chip *chip)
>  }
>  EXPORT_SYMBOL_GPL(dw_edma_remove);
>
> +int dw_edma_chan_info(struct dw_edma_chip *chip, unsigned int ch_idx,
> +		      struct dw_edma_chan_info *info)
> +{
> +	struct dw_edma *dw = chip->dw;
> +	struct dw_edma_chan *chan;
> +	struct dma_chan *dchan;
> +	u32 ch_cnt;
> +	int ret;
> +
> +	if (!chip || !info || !dw)
> +		return -EINVAL;
> +
> +	ch_cnt = dw->wr_ch_cnt + dw->rd_ch_cnt;
> +	if (ch_idx >= ch_cnt)
> +		return -EINVAL;
> +
> +	chan = &dw->chan[ch_idx];
> +	dchan = &chan->vc.chan;
> +
> +	ret = dw_edma_core_ch_info(dw, chan, info);
> +	if (ret)
> +		return ret;
> +
> +	info->irq = dw->irq[chan->irq_idx].irq;
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(dw_edma_chan_info);
> +
>  MODULE_LICENSE("GPL v2");
>  MODULE_DESCRIPTION("Synopsys DesignWare eDMA controller core driver");
>  MODULE_AUTHOR("Gustavo Pimentel <gustavo.pimentel@synopsys.com>");
> diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
> index abc97e375484..e92891ed5536 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.h
> +++ b/drivers/dma/dw-edma/dw-edma-core.h
> @@ -82,6 +82,7 @@ struct dw_edma_chan {
>  	struct msi_msg			msi;
>
>  	enum dw_edma_ch_irq_mode	irq_mode;
> +	u32				irq_idx;

can we directly save irq_number?

>
>  	enum dw_edma_request		request;
>  	enum dw_edma_status		status;
> @@ -95,6 +96,7 @@ struct dw_edma_irq {
>  	u32				wr_mask;
>  	u32				rd_mask;
>  	struct dw_edma			*dw;
> +	int				irq;
>  };
>
>  struct dw_edma {
> @@ -129,6 +131,7 @@ struct dw_edma_core_ops {
>  	void (*ch_config)(struct dw_edma_chan *chan);
>  	void (*debugfs_on)(struct dw_edma *dw);
>  	void (*ack_selfirq)(struct dw_edma *dw);
> +	void (*ch_info)(struct dw_edma_chan *chan, struct dw_edma_chan_info *info);
>  };
>
>  struct dw_edma_sg {
> @@ -219,6 +222,17 @@ int dw_edma_core_ack_selfirq(struct dw_edma *dw)
>  	return 0;
>  }
>
> +static inline
> +int dw_edma_core_ch_info(struct dw_edma *dw, struct dw_edma_chan *chan,
> +			 struct dw_edma_chan_info *info)

wrap int to previous line, check others.

Frank
> +{
> +	if (!dw->core->ch_info)
> +		return -EOPNOTSUPP;
> +
> +	dw->core->ch_info(chan, info);
> +	return 0;
> +}
> +
>  static inline
>  bool dw_edma_core_ch_ignore_irq(struct dw_edma_chan *chan)
>  {
> diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
> index 68e0d088570d..9c7908a76fff 100644
> --- a/drivers/dma/dw-edma/dw-edma-v0-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
> @@ -529,6 +529,12 @@ static void dw_edma_v0_core_ack_selfirq(struct dw_edma *dw)
>  	SET_BOTH_32(dw, int_clear, 0);
>  }
>
> +static void dw_edma_v0_core_ch_info(struct dw_edma_chan *chan,
> +				    struct dw_edma_chan_info *info)
> +{
> +	info->db_offset = offsetof(struct dw_edma_v0_regs, rd_int_status);
> +}
> +
>  static const struct dw_edma_core_ops dw_edma_v0_core = {
>  	.off = dw_edma_v0_core_off,
>  	.ch_count = dw_edma_v0_core_ch_count,
> @@ -538,6 +544,7 @@ static const struct dw_edma_core_ops dw_edma_v0_core = {
>  	.ch_config = dw_edma_v0_core_ch_config,
>  	.debugfs_on = dw_edma_v0_core_debugfs_on,
>  	.ack_selfirq = dw_edma_v0_core_ack_selfirq,
> +	.ch_info = dw_edma_v0_core_ch_info,
>  };
>
>  void dw_edma_v0_core_register(struct dw_edma *dw)
> diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
> index 53b31a974331..9fd78dc313e5 100644
> --- a/include/linux/dma/edma.h
> +++ b/include/linux/dma/edma.h
> @@ -129,10 +129,23 @@ struct dw_edma_chip {
>  	struct dw_edma		*dw;
>  };
>
> +/**
> + * struct dw_edma_chan_info - DW eDMA channel metadata
> + * @irq:	Linux IRQ number used by this channel's interrupt vector
> + * @db_offset:	offset within the eDMA register window that can be used as
> + *		an interrupt-emulation doorbell for this channel
> + */
> +struct dw_edma_chan_info {
> +	int			irq;
> +	resource_size_t		db_offset;
> +};
> +
>  /* Export to the platform drivers */
>  #if IS_REACHABLE(CONFIG_DW_EDMA)
>  int dw_edma_probe(struct dw_edma_chip *chip);
>  int dw_edma_remove(struct dw_edma_chip *chip);
> +int dw_edma_chan_info(struct dw_edma_chip *chip, unsigned int ch_idx,
> +		      struct dw_edma_chan_info *info);
>  #else
>  static inline int dw_edma_probe(struct dw_edma_chip *chip)
>  {
> @@ -143,6 +156,13 @@ static inline int dw_edma_remove(struct dw_edma_chip *chip)
>  {
>  	return 0;
>  }
> +
> +static inline int dw_edma_chan_info(struct dw_edma_chip *chip,
> +				    unsigned int ch_idx,
> +				    struct dw_edma_chan_info *info)
> +{
> +	return -ENODEV;
> +}
>  #endif /* CONFIG_DW_EDMA */
>
>  #endif /* _DW_EDMA_H */
> --
> 2.51.0
>

Re: [PATCH v4 3/9] dmaengine: dw-edma: Export per-channel IRQ and doorbell register offset

Posted by Koichiro Den 12 hours ago

On Fri, Feb 06, 2026 at 12:56:24PM -0500, Frank Li wrote:
> On Sat, Feb 07, 2026 at 02:26:40AM +0900, Koichiro Den wrote:
> > Endpoint controller drivers may need to expose or consume eDMA-related
> > resources (e.g. for remote programming or doorbell/self-tests). For
> > that, consumers need a stable way to discover the Linux IRQ used by a
> > given eDMA channel/vector and a register offset suitable for interrupt
> > emulation.
> >
> > Record each channel's IRQ-vector index and store the requested Linux IRQ
> > number. Add a core callback .ch_info() to provide core-specific metadata
> > and implement it for v0.
> >
> > Export dw_edma_chan_info() so that platform drivers can retrieve:
> >   - per-channel device name
> >   - Linux IRQ number for the channel's interrupt vector
> >   - offset of the register used as an emulated-interrupt doorbell within
> >     the eDMA register window.
> >
> > Signed-off-by: Koichiro Den <den@valinux.co.jp>
> > ---
> >  drivers/dma/dw-edma/dw-edma-core.c    | 31 +++++++++++++++++++++++++++
> >  drivers/dma/dw-edma/dw-edma-core.h    | 14 ++++++++++++
> >  drivers/dma/dw-edma/dw-edma-v0-core.c |  7 ++++++
> >  include/linux/dma/edma.h              | 20 +++++++++++++++++
> >  4 files changed, 72 insertions(+)
> >
> > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> > index dd01a9aa8ad8..147a5466e4e7 100644
> > --- a/drivers/dma/dw-edma/dw-edma-core.c
> > +++ b/drivers/dma/dw-edma/dw-edma-core.c
> > @@ -842,6 +842,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc)
> >  		else
> >  			pos = wr_alloc + chan->id % rd_alloc;
> >
> > +		chan->irq_idx = pos;
> >  		irq = &dw->irq[pos];
> >
> >  		if (chan->dir == EDMA_DIR_WRITE)
> > @@ -947,6 +948,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
> >  		if (irq_get_msi_desc(irq))
> >  			get_cached_msi_msg(irq, &dw->irq[0].msi);
> >
> > +		dw->irq[0].irq = irq;
> >  		dw->nr_irqs = 1;
> >  	} else {
> >  		/* Distribute IRQs equally among all channels */
> > @@ -973,6 +975,7 @@ static int dw_edma_irq_request(struct dw_edma *dw,
> >
> >  			if (irq_get_msi_desc(irq))
> >  				get_cached_msi_msg(irq, &dw->irq[i].msi);
> > +			dw->irq[i].irq = irq;
> >  		}
> >
> >  		dw->nr_irqs = i;
> > @@ -1098,6 +1101,34 @@ int dw_edma_remove(struct dw_edma_chip *chip)
> >  }
> >  EXPORT_SYMBOL_GPL(dw_edma_remove);
> >
> > +int dw_edma_chan_info(struct dw_edma_chip *chip, unsigned int ch_idx,
> > +		      struct dw_edma_chan_info *info)
> > +{
> > +	struct dw_edma *dw = chip->dw;
> > +	struct dw_edma_chan *chan;
> > +	struct dma_chan *dchan;
> > +	u32 ch_cnt;
> > +	int ret;
> > +
> > +	if (!chip || !info || !dw)
> > +		return -EINVAL;
> > +
> > +	ch_cnt = dw->wr_ch_cnt + dw->rd_ch_cnt;
> > +	if (ch_idx >= ch_cnt)
> > +		return -EINVAL;
> > +
> > +	chan = &dw->chan[ch_idx];
> > +	dchan = &chan->vc.chan;
> > +
> > +	ret = dw_edma_core_ch_info(dw, chan, info);
> > +	if (ret)
> > +		return ret;
> > +
> > +	info->irq = dw->irq[chan->irq_idx].irq;
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(dw_edma_chan_info);
> > +
> >  MODULE_LICENSE("GPL v2");
> >  MODULE_DESCRIPTION("Synopsys DesignWare eDMA controller core driver");
> >  MODULE_AUTHOR("Gustavo Pimentel <gustavo.pimentel@synopsys.com>");
> > diff --git a/drivers/dma/dw-edma/dw-edma-core.h b/drivers/dma/dw-edma/dw-edma-core.h
> > index abc97e375484..e92891ed5536 100644
> > --- a/drivers/dma/dw-edma/dw-edma-core.h
> > +++ b/drivers/dma/dw-edma/dw-edma-core.h
> > @@ -82,6 +82,7 @@ struct dw_edma_chan {
> >  	struct msi_msg			msi;
> >
> >  	enum dw_edma_ch_irq_mode	irq_mode;
> > +	u32				irq_idx;
> 
> can we directly save irq_number?

Yes, that makes sense. I'll address this in v5 together with the changes
based on the discussion here:
https://lore.kernel.org/dmaengine/cuihp4wo5bcku75myq7mfbfvyddwptitiyy6pz5ldq2l6robxk@kghlibxpr7wf/

> 
> >
> >  	enum dw_edma_request		request;
> >  	enum dw_edma_status		status;
> > @@ -95,6 +96,7 @@ struct dw_edma_irq {
> >  	u32				wr_mask;
> >  	u32				rd_mask;
> >  	struct dw_edma			*dw;
> > +	int				irq;
> >  };
> >
> >  struct dw_edma {
> > @@ -129,6 +131,7 @@ struct dw_edma_core_ops {
> >  	void (*ch_config)(struct dw_edma_chan *chan);
> >  	void (*debugfs_on)(struct dw_edma *dw);
> >  	void (*ack_selfirq)(struct dw_edma *dw);
> > +	void (*ch_info)(struct dw_edma_chan *chan, struct dw_edma_chan_info *info);
> >  };
> >
> >  struct dw_edma_sg {
> > @@ -219,6 +222,17 @@ int dw_edma_core_ack_selfirq(struct dw_edma *dw)
> >  	return 0;
> >  }
> >
> > +static inline
> > +int dw_edma_core_ch_info(struct dw_edma *dw, struct dw_edma_chan *chan,
> > +			 struct dw_edma_chan_info *info)
> 
> wrap int to previous line, check others.

Thanks for pointing that out. I'll update it for the same reasons as
discussed here:
https://lore.kernel.org/dmaengine/qktad6ggosznbznej7n2luxwkhr34f3egtojzjnkry4v2balbh@sfxxoii5yxoa/

Thanks,
Koichiro

> 
> Frank
> > +{
> > +	if (!dw->core->ch_info)
> > +		return -EOPNOTSUPP;
> > +
> > +	dw->core->ch_info(chan, info);
> > +	return 0;
> > +}
> > +
> >  static inline
> >  bool dw_edma_core_ch_ignore_irq(struct dw_edma_chan *chan)
> >  {
> > diff --git a/drivers/dma/dw-edma/dw-edma-v0-core.c b/drivers/dma/dw-edma/dw-edma-v0-core.c
> > index 68e0d088570d..9c7908a76fff 100644
> > --- a/drivers/dma/dw-edma/dw-edma-v0-core.c
> > +++ b/drivers/dma/dw-edma/dw-edma-v0-core.c
> > @@ -529,6 +529,12 @@ static void dw_edma_v0_core_ack_selfirq(struct dw_edma *dw)
> >  	SET_BOTH_32(dw, int_clear, 0);
> >  }
> >
> > +static void dw_edma_v0_core_ch_info(struct dw_edma_chan *chan,
> > +				    struct dw_edma_chan_info *info)
> > +{
> > +	info->db_offset = offsetof(struct dw_edma_v0_regs, rd_int_status);
> > +}
> > +
> >  static const struct dw_edma_core_ops dw_edma_v0_core = {
> >  	.off = dw_edma_v0_core_off,
> >  	.ch_count = dw_edma_v0_core_ch_count,
> > @@ -538,6 +544,7 @@ static const struct dw_edma_core_ops dw_edma_v0_core = {
> >  	.ch_config = dw_edma_v0_core_ch_config,
> >  	.debugfs_on = dw_edma_v0_core_debugfs_on,
> >  	.ack_selfirq = dw_edma_v0_core_ack_selfirq,
> > +	.ch_info = dw_edma_v0_core_ch_info,
> >  };
> >
> >  void dw_edma_v0_core_register(struct dw_edma *dw)
> > diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
> > index 53b31a974331..9fd78dc313e5 100644
> > --- a/include/linux/dma/edma.h
> > +++ b/include/linux/dma/edma.h
> > @@ -129,10 +129,23 @@ struct dw_edma_chip {
> >  	struct dw_edma		*dw;
> >  };
> >
> > +/**
> > + * struct dw_edma_chan_info - DW eDMA channel metadata
> > + * @irq:	Linux IRQ number used by this channel's interrupt vector
> > + * @db_offset:	offset within the eDMA register window that can be used as
> > + *		an interrupt-emulation doorbell for this channel
> > + */
> > +struct dw_edma_chan_info {
> > +	int			irq;
> > +	resource_size_t		db_offset;
> > +};
> > +
> >  /* Export to the platform drivers */
> >  #if IS_REACHABLE(CONFIG_DW_EDMA)
> >  int dw_edma_probe(struct dw_edma_chip *chip);
> >  int dw_edma_remove(struct dw_edma_chip *chip);
> > +int dw_edma_chan_info(struct dw_edma_chip *chip, unsigned int ch_idx,
> > +		      struct dw_edma_chan_info *info);
> >  #else
> >  static inline int dw_edma_probe(struct dw_edma_chip *chip)
> >  {
> > @@ -143,6 +156,13 @@ static inline int dw_edma_remove(struct dw_edma_chip *chip)
> >  {
> >  	return 0;
> >  }
> > +
> > +static inline int dw_edma_chan_info(struct dw_edma_chip *chip,
> > +				    unsigned int ch_idx,
> > +				    struct dw_edma_chan_info *info)
> > +{
> > +	return -ENODEV;
> > +}
> >  #endif /* CONFIG_DW_EDMA */
> >
> >  #endif /* _DW_EDMA_H */
> > --
> > 2.51.0
> >