[PATCH v1 0/3] CPM6 Channel Separation Support

[PATCH v1 0/3] CPM6 Channel Separation Support

[Devendra K Verma]

'Designware Cores PCI Express DM Controller - Reference
Manual', section 3.2.34.3, VSEC for DEVICE INFORMATION supports
the channel separation mechanisms. Basically, the HDMA IP allows
the user to configure the separation between DMA channel
registers and retrieve it via the VSEC capability mentioned
above.
In order to use the VSEC functionality following changes have
been made:

o For Xilinx IP alone, the macros declared are made device
  name agnostic to expand the usage of macros for similar
  functionality.
o Utilize the existing VSEC implementation to retrieve
  the channel separation and translate it to correct size.
o Modify the structs and functions to calculate correct
  DMA channel register base using the channel, direction
  and channel separation selected.

Devendra K Verma (3):
  dmaengine: dw-edma: Make Xilinx Macros Dev Name Agnostic
  dmaengine: dw-edma: Enable Chan Separation via VSEC
  dmaengine: dw-edma: Add changes to support Channel Separation

 drivers/dma/dw-edma/dw-edma-pcie.c       | 87 +++++++++++++++---------
 drivers/dma/dw-edma/dw-hdma-v0-core.c    | 23 ++++---
 drivers/dma/dw-edma/dw-hdma-v0-debugfs.c | 17 ++---
 drivers/dma/dw-edma/dw-hdma-v0-regs.h    | 10 ---
 include/linux/dma/edma.h                 |  1 +
 5 files changed, 77 insertions(+), 61 deletions(-)

-- 
2.43.0

[PATCH v1 1/3] dmaengine: dw-edma: Make Xilinx Macros Dev Name Agnostic

[Devendra K Verma]

Xilinx specific macros for MDB device can be reused for the
Xilinx supported other similar IP such as CPM6.
Renamed the Xilinx specific macros in a way that can be
reused for Xilinx supported upcoming IP, CPM6.
Naming is in accordance with the naming done for Synopsys macros.

Signed-off-by: Devendra K Verma <devverma@amd.com>
---
 drivers/dma/dw-edma/dw-edma-pcie.c | 58 +++++++++++++++---------------
 1 file changed, 29 insertions(+), 29 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
index 791c46e8ae4c..ec5e057a0f11 100644
--- a/drivers/dma/dw-edma/dw-edma-pcie.c
+++ b/drivers/dma/dw-edma/dw-edma-pcie.c
@@ -29,21 +29,21 @@
 #define PCI_DEVICE_ID_XILINX_B054		0xb054
 #define PCI_DEVICE_ID_XILINX_B00F		0xb00f
 
-#define DW_PCIE_XILINX_MDB_VSEC_DMA_ID		0x6
-#define DW_PCIE_XILINX_MDB_VSEC_ID		0x20
-#define DW_PCIE_XILINX_MDB_VSEC_DMA_BAR		GENMASK(10, 8)
-#define DW_PCIE_XILINX_MDB_VSEC_DMA_MAP		GENMASK(2, 0)
-#define DW_PCIE_XILINX_MDB_VSEC_DMA_WR_CH	GENMASK(9, 0)
-#define DW_PCIE_XILINX_MDB_VSEC_DMA_RD_CH	GENMASK(25, 16)
-
-#define DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_HIGH	0xc
-#define DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_LOW	0x8
-#define DW_PCIE_XILINX_MDB_INVALID_ADDR		(~0ULL)
-
-#define DW_PCIE_XILINX_MDB_LL_OFF_GAP		0x200000
-#define DW_PCIE_XILINX_MDB_LL_SIZE		0x800
-#define DW_PCIE_XILINX_MDB_DT_OFF_GAP		0x100000
-#define DW_PCIE_XILINX_MDB_DT_SIZE		0x800
+#define DW_PCIE_XILINX_VSEC_DMA_ID		0x6
+#define DW_PCIE_XILINX_VSEC_ID			0x20
+#define DW_PCIE_XILINX_VSEC_DMA_BAR		GENMASK(10, 8)
+#define DW_PCIE_XILINX_VSEC_DMA_MAP		GENMASK(2, 0)
+#define DW_PCIE_XILINX_VSEC_DMA_WR_CH		GENMASK(9, 0)
+#define DW_PCIE_XILINX_VSEC_DMA_RD_CH		GENMASK(25, 16)
+
+#define DW_PCIE_XILINX_DEVMEM_OFF_REG_HIGH	0xc
+#define DW_PCIE_XILINX_DEVMEM_OFF_REG_LOW	0x8
+#define DW_PCIE_XILINX_INVALID_ADDR		(~0ULL)
+
+#define DW_PCIE_XILINX_LL_OFF_GAP		0x200000
+#define DW_PCIE_XILINX_LL_SIZE			0x800
+#define DW_PCIE_XILINX_DT_OFF_GAP		0x100000
+#define DW_PCIE_XILINX_DT_SIZE			0x800
 
 #define DW_BLOCK(a, b, c) \
 	{ \
@@ -258,10 +258,10 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
 	u16 vsec;
 	u64 off;
 
-	pdata->devmem_phys_off = DW_PCIE_XILINX_MDB_INVALID_ADDR;
+	pdata->devmem_phys_off = DW_PCIE_XILINX_INVALID_ADDR;
 
 	vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_XILINX,
-					DW_PCIE_XILINX_MDB_VSEC_DMA_ID);
+					DW_PCIE_XILINX_VSEC_DMA_ID);
 	if (!vsec)
 		return;
 
@@ -272,18 +272,18 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
 
 	pci_dbg(pdev, "Detected Xilinx PCIe Vendor-Specific Extended Capability DMA\n");
 	pci_read_config_dword(pdev, vsec + 0x8, &val);
-	map = FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_MAP, val);
+	map = FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_MAP, val);
 	if (map != EDMA_MF_HDMA_NATIVE)
 		return;
 
 	pdata->mf = map;
-	pdata->rg.bar = FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_BAR, val);
+	pdata->rg.bar = FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_BAR, val);
 
 	pci_read_config_dword(pdev, vsec + 0xc, &val);
 	pdata->wr_ch_cnt = min(pdata->wr_ch_cnt,
-			       FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_WR_CH, val));
+			       FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_WR_CH, val));
 	pdata->rd_ch_cnt = min(pdata->rd_ch_cnt,
-			       FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_RD_CH, val));
+			       FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_RD_CH, val));
 
 	pci_read_config_dword(pdev, vsec + 0x14, &val);
 	off = val;
@@ -293,16 +293,16 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
 	pdata->rg.off = off;
 
 	vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_XILINX,
-					DW_PCIE_XILINX_MDB_VSEC_ID);
+					DW_PCIE_XILINX_VSEC_ID);
 	if (!vsec)
 		return;
 
 	pci_read_config_dword(pdev,
-			      vsec + DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_HIGH,
+			      vsec + DW_PCIE_XILINX_DEVMEM_OFF_REG_HIGH,
 			      &val);
 	off = val;
 	pci_read_config_dword(pdev,
-			      vsec + DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_LOW,
+			      vsec + DW_PCIE_XILINX_DEVMEM_OFF_REG_LOW,
 			      &val);
 	off <<= 32;
 	off |= val;
@@ -360,7 +360,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 		 * address use the non-LL mode or simple mode supported by
 		 * the HDMA IP.
 		 */
-		if (vsec_data->devmem_phys_off == DW_PCIE_XILINX_MDB_INVALID_ADDR)
+		if (vsec_data->devmem_phys_off == DW_PCIE_XILINX_INVALID_ADDR)
 			non_ll = true;
 
 		/*
@@ -370,10 +370,10 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 		 */
 		if (!non_ll)
 			dw_edma_set_chan_region_offset(vsec_data, BAR_2, 0,
-						       DW_PCIE_XILINX_MDB_LL_OFF_GAP,
-						       DW_PCIE_XILINX_MDB_LL_SIZE,
-						       DW_PCIE_XILINX_MDB_DT_OFF_GAP,
-						       DW_PCIE_XILINX_MDB_DT_SIZE);
+						       DW_PCIE_XILINX_LL_OFF_GAP,
+						       DW_PCIE_XILINX_LL_SIZE,
+						       DW_PCIE_XILINX_DT_OFF_GAP,
+						       DW_PCIE_XILINX_DT_SIZE);
 	}
 
 	/* Mapping PCI BAR regions */
-- 
2.43.0

Re: [PATCH v1 1/3] dmaengine: dw-edma: Make Xilinx Macros Dev Name Agnostic

[Frank Li]

On Wed, Jul 22, 2026 at 04:46:38PM +0530, Devendra K Verma wrote:
> Xilinx specific macros for MDB device can be reused for the
> Xilinx supported other similar IP such as CPM6.
> Renamed the Xilinx specific macros in a way that can be
> reused for Xilinx supported upcoming IP, CPM6.
> Naming is in accordance with the naming done for Synopsys macros.
>
> Signed-off-by: Devendra K Verma <devverma@amd.com>
> ---

I don't think it is necessary to remove MDB. You may mention somewhere
CMP6 compatible with MDB. It is quite common in driver.

The major concerns is that if a incompatible devices appear, such as CMP7,
which have special registers, need add _MDB_ back.

Frank

>  drivers/dma/dw-edma/dw-edma-pcie.c | 58 +++++++++++++++---------------
>  1 file changed, 29 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
> index 791c46e8ae4c..ec5e057a0f11 100644
> --- a/drivers/dma/dw-edma/dw-edma-pcie.c
> +++ b/drivers/dma/dw-edma/dw-edma-pcie.c
> @@ -29,21 +29,21 @@
>  #define PCI_DEVICE_ID_XILINX_B054		0xb054
>  #define PCI_DEVICE_ID_XILINX_B00F		0xb00f
>
> -#define DW_PCIE_XILINX_MDB_VSEC_DMA_ID		0x6
> -#define DW_PCIE_XILINX_MDB_VSEC_ID		0x20
> -#define DW_PCIE_XILINX_MDB_VSEC_DMA_BAR		GENMASK(10, 8)
> -#define DW_PCIE_XILINX_MDB_VSEC_DMA_MAP		GENMASK(2, 0)
> -#define DW_PCIE_XILINX_MDB_VSEC_DMA_WR_CH	GENMASK(9, 0)
> -#define DW_PCIE_XILINX_MDB_VSEC_DMA_RD_CH	GENMASK(25, 16)
> -
> -#define DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_HIGH	0xc
> -#define DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_LOW	0x8
> -#define DW_PCIE_XILINX_MDB_INVALID_ADDR		(~0ULL)
> -
> -#define DW_PCIE_XILINX_MDB_LL_OFF_GAP		0x200000
> -#define DW_PCIE_XILINX_MDB_LL_SIZE		0x800
> -#define DW_PCIE_XILINX_MDB_DT_OFF_GAP		0x100000
> -#define DW_PCIE_XILINX_MDB_DT_SIZE		0x800
> +#define DW_PCIE_XILINX_VSEC_DMA_ID		0x6
> +#define DW_PCIE_XILINX_VSEC_ID			0x20
> +#define DW_PCIE_XILINX_VSEC_DMA_BAR		GENMASK(10, 8)
> +#define DW_PCIE_XILINX_VSEC_DMA_MAP		GENMASK(2, 0)
> +#define DW_PCIE_XILINX_VSEC_DMA_WR_CH		GENMASK(9, 0)
> +#define DW_PCIE_XILINX_VSEC_DMA_RD_CH		GENMASK(25, 16)
> +
> +#define DW_PCIE_XILINX_DEVMEM_OFF_REG_HIGH	0xc
> +#define DW_PCIE_XILINX_DEVMEM_OFF_REG_LOW	0x8
> +#define DW_PCIE_XILINX_INVALID_ADDR		(~0ULL)
> +
> +#define DW_PCIE_XILINX_LL_OFF_GAP		0x200000
> +#define DW_PCIE_XILINX_LL_SIZE			0x800
> +#define DW_PCIE_XILINX_DT_OFF_GAP		0x100000
> +#define DW_PCIE_XILINX_DT_SIZE			0x800
>
>  #define DW_BLOCK(a, b, c) \
>  	{ \
> @@ -258,10 +258,10 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
>  	u16 vsec;
>  	u64 off;
>
> -	pdata->devmem_phys_off = DW_PCIE_XILINX_MDB_INVALID_ADDR;
> +	pdata->devmem_phys_off = DW_PCIE_XILINX_INVALID_ADDR;
>
>  	vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_XILINX,
> -					DW_PCIE_XILINX_MDB_VSEC_DMA_ID);
> +					DW_PCIE_XILINX_VSEC_DMA_ID);
>  	if (!vsec)
>  		return;
>
> @@ -272,18 +272,18 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
>
>  	pci_dbg(pdev, "Detected Xilinx PCIe Vendor-Specific Extended Capability DMA\n");
>  	pci_read_config_dword(pdev, vsec + 0x8, &val);
> -	map = FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_MAP, val);
> +	map = FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_MAP, val);
>  	if (map != EDMA_MF_HDMA_NATIVE)
>  		return;
>
>  	pdata->mf = map;
> -	pdata->rg.bar = FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_BAR, val);
> +	pdata->rg.bar = FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_BAR, val);
>
>  	pci_read_config_dword(pdev, vsec + 0xc, &val);
>  	pdata->wr_ch_cnt = min(pdata->wr_ch_cnt,
> -			       FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_WR_CH, val));
> +			       FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_WR_CH, val));
>  	pdata->rd_ch_cnt = min(pdata->rd_ch_cnt,
> -			       FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_RD_CH, val));
> +			       FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_RD_CH, val));
>
>  	pci_read_config_dword(pdev, vsec + 0x14, &val);
>  	off = val;
> @@ -293,16 +293,16 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
>  	pdata->rg.off = off;
>
>  	vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_XILINX,
> -					DW_PCIE_XILINX_MDB_VSEC_ID);
> +					DW_PCIE_XILINX_VSEC_ID);
>  	if (!vsec)
>  		return;
>
>  	pci_read_config_dword(pdev,
> -			      vsec + DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_HIGH,
> +			      vsec + DW_PCIE_XILINX_DEVMEM_OFF_REG_HIGH,
>  			      &val);
>  	off = val;
>  	pci_read_config_dword(pdev,
> -			      vsec + DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_LOW,
> +			      vsec + DW_PCIE_XILINX_DEVMEM_OFF_REG_LOW,
>  			      &val);
>  	off <<= 32;
>  	off |= val;
> @@ -360,7 +360,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
>  		 * address use the non-LL mode or simple mode supported by
>  		 * the HDMA IP.
>  		 */
> -		if (vsec_data->devmem_phys_off == DW_PCIE_XILINX_MDB_INVALID_ADDR)
> +		if (vsec_data->devmem_phys_off == DW_PCIE_XILINX_INVALID_ADDR)
>  			non_ll = true;
>
>  		/*
> @@ -370,10 +370,10 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
>  		 */
>  		if (!non_ll)
>  			dw_edma_set_chan_region_offset(vsec_data, BAR_2, 0,
> -						       DW_PCIE_XILINX_MDB_LL_OFF_GAP,
> -						       DW_PCIE_XILINX_MDB_LL_SIZE,
> -						       DW_PCIE_XILINX_MDB_DT_OFF_GAP,
> -						       DW_PCIE_XILINX_MDB_DT_SIZE);
> +						       DW_PCIE_XILINX_LL_OFF_GAP,
> +						       DW_PCIE_XILINX_LL_SIZE,
> +						       DW_PCIE_XILINX_DT_OFF_GAP,
> +						       DW_PCIE_XILINX_DT_SIZE);
>  	}
>
>  	/* Mapping PCI BAR regions */
> --
> 2.43.0
>

Re: [PATCH v1 1/3] dmaengine: dw-edma: Make Xilinx Macros Dev Name Agnostic

[Frank Li]

On Thu, Jul 23, 2026 at 03:53:13PM +0530, Verma, Devendra wrote:
>
>
> On 22-Jul-26 20:21, Frank Li wrote:
> > On Wed, Jul 22, 2026 at 04:46:38PM +0530, Devendra K Verma wrote:
> > > Xilinx specific macros for MDB device can be reused for the
> > > Xilinx supported other similar IP such as CPM6.
> > > Renamed the Xilinx specific macros in a way that can be
> > > reused for Xilinx supported upcoming IP, CPM6.
> > > Naming is in accordance with the naming done for Synopsys macros.
> > >
> > > Signed-off-by: Devendra K Verma <devverma@amd.com>
> > > ---
> >
> > I don't think it is necessary to remove MDB. You may mention somewhere
> > CMP6 compatible with MDB. It is quite common in driver.
> >
> > The major concerns is that if a incompatible devices appear, such as CMP7,
> > which have special registers, need add _MDB_ back.
> >
> > Frank
> >
>
> The MDB was used cause at that time only Xilinx MDB was the IP to go
> public.
> I agree with your suggestion but the idea used here is that, for the
> common functionalities use the names which are affiliated to vendor
> that is Xilinx and can be used across the IP having the similarity.
> In case specific functionality is required for MDB or CPM6 then
> it can be associated using vendor + device name, that way it is easy
> to identify which ones are common and specific to the IP.
>
> Currently, if any functionality added for MDB ONLY then it would be
> assumed to be supported on Xilinx CPM6 as well.

Rename when this case really appear.

Frank

> To remove the confusion
> extra comment would be required to inform which functionality is
> supported for which IP. That is why the removal of MDB appoach was taken
> to reduce the confusion and work. The first approach looked clean.
>
> Please let me know your thougths.
>
> -Devendra
>
> > >   drivers/dma/dw-edma/dw-edma-pcie.c | 58 +++++++++++++++---------------
> > >   1 file changed, 29 insertions(+), 29 deletions(-)
> > >
> > > diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
> > > index 791c46e8ae4c..ec5e057a0f11 100644
> > > --- a/drivers/dma/dw-edma/dw-edma-pcie.c
> > > +++ b/drivers/dma/dw-edma/dw-edma-pcie.c
> > > @@ -29,21 +29,21 @@
> > >   #define PCI_DEVICE_ID_XILINX_B054		0xb054
> > >   #define PCI_DEVICE_ID_XILINX_B00F		0xb00f
> > >
> > > -#define DW_PCIE_XILINX_MDB_VSEC_DMA_ID		0x6
> > > -#define DW_PCIE_XILINX_MDB_VSEC_ID		0x20
> > > -#define DW_PCIE_XILINX_MDB_VSEC_DMA_BAR		GENMASK(10, 8)
> > > -#define DW_PCIE_XILINX_MDB_VSEC_DMA_MAP		GENMASK(2, 0)
> > > -#define DW_PCIE_XILINX_MDB_VSEC_DMA_WR_CH	GENMASK(9, 0)
> > > -#define DW_PCIE_XILINX_MDB_VSEC_DMA_RD_CH	GENMASK(25, 16)
> > > -
> > > -#define DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_HIGH	0xc
> > > -#define DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_LOW	0x8
> > > -#define DW_PCIE_XILINX_MDB_INVALID_ADDR		(~0ULL)
> > > -
> > > -#define DW_PCIE_XILINX_MDB_LL_OFF_GAP		0x200000
> > > -#define DW_PCIE_XILINX_MDB_LL_SIZE		0x800
> > > -#define DW_PCIE_XILINX_MDB_DT_OFF_GAP		0x100000
> > > -#define DW_PCIE_XILINX_MDB_DT_SIZE		0x800
> > > +#define DW_PCIE_XILINX_VSEC_DMA_ID		0x6
> > > +#define DW_PCIE_XILINX_VSEC_ID			0x20
> > > +#define DW_PCIE_XILINX_VSEC_DMA_BAR		GENMASK(10, 8)
> > > +#define DW_PCIE_XILINX_VSEC_DMA_MAP		GENMASK(2, 0)
> > > +#define DW_PCIE_XILINX_VSEC_DMA_WR_CH		GENMASK(9, 0)
> > > +#define DW_PCIE_XILINX_VSEC_DMA_RD_CH		GENMASK(25, 16)
> > > +
> > > +#define DW_PCIE_XILINX_DEVMEM_OFF_REG_HIGH	0xc
> > > +#define DW_PCIE_XILINX_DEVMEM_OFF_REG_LOW	0x8
> > > +#define DW_PCIE_XILINX_INVALID_ADDR		(~0ULL)
> > > +
> > > +#define DW_PCIE_XILINX_LL_OFF_GAP		0x200000
> > > +#define DW_PCIE_XILINX_LL_SIZE			0x800
> > > +#define DW_PCIE_XILINX_DT_OFF_GAP		0x100000
> > > +#define DW_PCIE_XILINX_DT_SIZE			0x800
> > >
> > >   #define DW_BLOCK(a, b, c) \
> > >   	{ \
> > > @@ -258,10 +258,10 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
> > >   	u16 vsec;
> > >   	u64 off;
> > >
> > > -	pdata->devmem_phys_off = DW_PCIE_XILINX_MDB_INVALID_ADDR;
> > > +	pdata->devmem_phys_off = DW_PCIE_XILINX_INVALID_ADDR;
> > >
> > >   	vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_XILINX,
> > > -					DW_PCIE_XILINX_MDB_VSEC_DMA_ID);
> > > +					DW_PCIE_XILINX_VSEC_DMA_ID);
> > >   	if (!vsec)
> > >   		return;
> > >
> > > @@ -272,18 +272,18 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
> > >
> > >   	pci_dbg(pdev, "Detected Xilinx PCIe Vendor-Specific Extended Capability DMA\n");
> > >   	pci_read_config_dword(pdev, vsec + 0x8, &val);
> > > -	map = FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_MAP, val);
> > > +	map = FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_MAP, val);
> > >   	if (map != EDMA_MF_HDMA_NATIVE)
> > >   		return;
> > >
> > >   	pdata->mf = map;
> > > -	pdata->rg.bar = FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_BAR, val);
> > > +	pdata->rg.bar = FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_BAR, val);
> > >
> > >   	pci_read_config_dword(pdev, vsec + 0xc, &val);
> > >   	pdata->wr_ch_cnt = min(pdata->wr_ch_cnt,
> > > -			       FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_WR_CH, val));
> > > +			       FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_WR_CH, val));
> > >   	pdata->rd_ch_cnt = min(pdata->rd_ch_cnt,
> > > -			       FIELD_GET(DW_PCIE_XILINX_MDB_VSEC_DMA_RD_CH, val));
> > > +			       FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_RD_CH, val));
> > >
> > >   	pci_read_config_dword(pdev, vsec + 0x14, &val);
> > >   	off = val;
> > > @@ -293,16 +293,16 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
> > >   	pdata->rg.off = off;
> > >
> > >   	vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_XILINX,
> > > -					DW_PCIE_XILINX_MDB_VSEC_ID);
> > > +					DW_PCIE_XILINX_VSEC_ID);
> > >   	if (!vsec)
> > >   		return;
> > >
> > >   	pci_read_config_dword(pdev,
> > > -			      vsec + DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_HIGH,
> > > +			      vsec + DW_PCIE_XILINX_DEVMEM_OFF_REG_HIGH,
> > >   			      &val);
> > >   	off = val;
> > >   	pci_read_config_dword(pdev,
> > > -			      vsec + DW_PCIE_XILINX_MDB_DEVMEM_OFF_REG_LOW,
> > > +			      vsec + DW_PCIE_XILINX_DEVMEM_OFF_REG_LOW,
> > >   			      &val);
> > >   	off <<= 32;
> > >   	off |= val;
> > > @@ -360,7 +360,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
> > >   		 * address use the non-LL mode or simple mode supported by
> > >   		 * the HDMA IP.
> > >   		 */
> > > -		if (vsec_data->devmem_phys_off == DW_PCIE_XILINX_MDB_INVALID_ADDR)
> > > +		if (vsec_data->devmem_phys_off == DW_PCIE_XILINX_INVALID_ADDR)
> > >   			non_ll = true;
> > >
> > >   		/*
> > > @@ -370,10 +370,10 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
> > >   		 */
> > >   		if (!non_ll)
> > >   			dw_edma_set_chan_region_offset(vsec_data, BAR_2, 0,
> > > -						       DW_PCIE_XILINX_MDB_LL_OFF_GAP,
> > > -						       DW_PCIE_XILINX_MDB_LL_SIZE,
> > > -						       DW_PCIE_XILINX_MDB_DT_OFF_GAP,
> > > -						       DW_PCIE_XILINX_MDB_DT_SIZE);
> > > +						       DW_PCIE_XILINX_LL_OFF_GAP,
> > > +						       DW_PCIE_XILINX_LL_SIZE,
> > > +						       DW_PCIE_XILINX_DT_OFF_GAP,
> > > +						       DW_PCIE_XILINX_DT_SIZE);
> > >   	}
> > >
> > >   	/* Mapping PCI BAR regions */
> > > --
> > > 2.43.0
> > >
>

[PATCH v1 2/3] dmaengine: dw-edma: Enable Chan Separation via VSEC

[Devendra K Verma]

As per, 'Designware Cores PCI Express DM Controller - Reference
Manual', section 3.2.34.3, VSEC for DEVICE INFORMATION supports
the channel separation mechanisms. Basically, the HDMA IP allows
the user to configure the separation between DMA channel
registers and retrieve it via the VSEC capability mentioned
above.

HDMA IP supports the channel separation up to 32K but for
the simplicity channel separation support has been added till
4K. As and when required the function can be expanded to include
the higher sizes for channel separation.
Supported and missed out sizes are:
8K (0x5), 16K (0x6), 32K (0x7)

Signed-off-by: Devendra K Verma <devverma@amd.com>
---
 drivers/dma/dw-edma/dw-edma-pcie.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
index ec5e057a0f11..6295d01ba2f7 100644
--- a/drivers/dma/dw-edma/dw-edma-pcie.c
+++ b/drivers/dma/dw-edma/dw-edma-pcie.c
@@ -33,6 +33,7 @@
 #define DW_PCIE_XILINX_VSEC_ID			0x20
 #define DW_PCIE_XILINX_VSEC_DMA_BAR		GENMASK(10, 8)
 #define DW_PCIE_XILINX_VSEC_DMA_MAP		GENMASK(2, 0)
+#define DW_PCIE_XILINX_VSEC_CH_SEP		GENMASK(18, 16)
 #define DW_PCIE_XILINX_VSEC_DMA_WR_CH		GENMASK(9, 0)
 #define DW_PCIE_XILINX_VSEC_DMA_RD_CH		GENMASK(25, 16)
 
@@ -73,6 +74,7 @@ struct dw_edma_pcie_data {
 	u16				wr_ch_cnt;
 	u16				rd_ch_cnt;
 	u64				devmem_phys_off;
+	u32				ch_sep_sz;
 };
 
 static const struct dw_edma_pcie_data snps_edda_data = {
@@ -127,7 +129,7 @@ static const struct dw_edma_pcie_data xilinx_mdb_data = {
 };
 
 static const struct dw_edma_pcie_data xilinx_cpm6_dma_data = {
-	/* MDB registers location */
+	/* CPM6 registers location */
 	.rg.bar				= BAR_0,
 	.rg.off				= SZ_4K,	/*  4 Kbytes */
 	.rg.sz				= SZ_8K,	/*  8 Kbytes */
@@ -189,6 +191,23 @@ static int dw_edma_pcie_irq_vector(struct device *dev, unsigned int nr)
 	return pci_irq_vector(to_pci_dev(dev), nr);
 }
 
+static u32 dw_edma_get_ch_sep_sz(u32 ch_sep_val)
+{
+	switch (ch_sep_val) {
+	default:
+	case 0:
+		return 256;
+	case 1:
+		return 512;
+	case 2:
+		return 1024;
+	case 3:
+		return 2048;
+	case 4:
+		return 4096;
+	}
+}
+
 static u64 dw_edma_pcie_address(struct device *dev, phys_addr_t cpu_addr)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
@@ -278,6 +297,8 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
 
 	pdata->mf = map;
 	pdata->rg.bar = FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_BAR, val);
+	pdata->ch_sep_sz = dw_edma_get_ch_sep_sz(FIELD_GET(DW_PCIE_XILINX_VSEC_CH_SEP,
+							   val));
 
 	pci_read_config_dword(pdev, vsec + 0xc, &val);
 	pdata->wr_ch_cnt = min(pdata->wr_ch_cnt,
@@ -324,9 +345,9 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 	struct dw_edma_pcie_data *pdata = (void *)pid->driver_data;
 	struct device *dev = &pdev->dev;
 	struct dw_edma_chip *chip;
+	bool non_ll = false;
 	int err, nr_irqs;
 	int i, mask;
-	bool non_ll = false;
 
 	if (!pdata)
 		return -ENODEV;
-- 
2.43.0

Re: [PATCH v1 2/3] dmaengine: dw-edma: Enable Chan Separation via VSEC

[Frank Li]

On Wed, Jul 22, 2026 at 04:46:39PM +0530, Devendra K Verma wrote:
> As per, 'Designware Cores PCI Express DM Controller - Reference
> Manual', section 3.2.34.3, VSEC for DEVICE INFORMATION supports
> the channel separation mechanisms. Basically, the HDMA IP allows
> the user to configure the separation between DMA channel
> registers and retrieve it via the VSEC capability mentioned
> above.
>
> HDMA IP supports the channel separation up to 32K but for
> the simplicity channel separation support has been added till
> 4K. As and when required the function can be expanded to include
> the higher sizes for channel separation.
> Supported and missed out sizes are:
> 8K (0x5), 16K (0x6), 32K (0x7)
>
> Signed-off-by: Devendra K Verma <devverma@amd.com>
> ---
>  drivers/dma/dw-edma/dw-edma-pcie.c | 25 +++++++++++++++++++++++--
>  1 file changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
> index ec5e057a0f11..6295d01ba2f7 100644
> --- a/drivers/dma/dw-edma/dw-edma-pcie.c
> +++ b/drivers/dma/dw-edma/dw-edma-pcie.c
> @@ -33,6 +33,7 @@
>  #define DW_PCIE_XILINX_VSEC_ID			0x20
>  #define DW_PCIE_XILINX_VSEC_DMA_BAR		GENMASK(10, 8)
>  #define DW_PCIE_XILINX_VSEC_DMA_MAP		GENMASK(2, 0)
> +#define DW_PCIE_XILINX_VSEC_CH_SEP		GENMASK(18, 16)

Can keep as bit pos order for the same register?

>  #define DW_PCIE_XILINX_VSEC_DMA_WR_CH		GENMASK(9, 0)
>  #define DW_PCIE_XILINX_VSEC_DMA_RD_CH		GENMASK(25, 16)
>
> @@ -73,6 +74,7 @@ struct dw_edma_pcie_data {
>  	u16				wr_ch_cnt;
>  	u16				rd_ch_cnt;
>  	u64				devmem_phys_off;
> +	u32				ch_sep_sz;
>  };
>
>  static const struct dw_edma_pcie_data snps_edda_data = {
> @@ -127,7 +129,7 @@ static const struct dw_edma_pcie_data xilinx_mdb_data = {
>  };
>
>  static const struct dw_edma_pcie_data xilinx_cpm6_dma_data = {
> -	/* MDB registers location */
> +	/* CPM6 registers location */
>  	.rg.bar				= BAR_0,
>  	.rg.off				= SZ_4K,	/*  4 Kbytes */
>  	.rg.sz				= SZ_8K,	/*  8 Kbytes */
> @@ -189,6 +191,23 @@ static int dw_edma_pcie_irq_vector(struct device *dev, unsigned int nr)
>  	return pci_irq_vector(to_pci_dev(dev), nr);
>  }
>
> +static u32 dw_edma_get_ch_sep_sz(u32 ch_sep_val)
> +{
> +	switch (ch_sep_val) {
> +	default:
> +	case 0:
> +		return 256;
> +	case 1:
> +		return 512;
> +	case 2:
> +		return 1024;
> +	case 3:
> +		return 2048;
> +	case 4:
> +		return 4096;
> +	}

	256 << ch_sep_val ?


> +}
> +
>  static u64 dw_edma_pcie_address(struct device *dev, phys_addr_t cpu_addr)
>  {
>  	struct pci_dev *pdev = to_pci_dev(dev);
> @@ -278,6 +297,8 @@ static void dw_edma_pcie_get_xilinx_dma_data(struct pci_dev *pdev,
>
>  	pdata->mf = map;
>  	pdata->rg.bar = FIELD_GET(DW_PCIE_XILINX_VSEC_DMA_BAR, val);
> +	pdata->ch_sep_sz = dw_edma_get_ch_sep_sz(FIELD_GET(DW_PCIE_XILINX_VSEC_CH_SEP,
> +							   val));
>
>  	pci_read_config_dword(pdev, vsec + 0xc, &val);
>  	pdata->wr_ch_cnt = min(pdata->wr_ch_cnt,
> @@ -324,9 +345,9 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
>  	struct dw_edma_pcie_data *pdata = (void *)pid->driver_data;
>  	struct device *dev = &pdev->dev;
>  	struct dw_edma_chip *chip;
> +	bool non_ll = false;
>  	int err, nr_irqs;
>  	int i, mask;
> -	bool non_ll = false;

unnessary change here.

Frank
>
>  	if (!pdata)
>  		return -ENODEV;
> --
> 2.43.0
>

[PATCH v1 3/3] dmaengine: dw-edma: Add changes to support Channel Separation

[Devendra K Verma]

Following changes are made:
o In 'struct dw_hdma_v0_ch_regs', it is assumed the channel
  separation as 256-bytes which is default, but if an IP is
  configured for a different size of channel separation then
  user can retrieve it using the supported VSEC (0x6).
  Modified the struct to work with the channel separation
  supported by IP.
  CPM6 supports channel separation, default is 512.
o Changes in macros / functions where address of the channel
  is accessed based on channel index and direction. It enables
  the calculation of the channel reg base address based on
  the selected channel separation.
o Struct removed - dw_hdma_v0_ch, dw_hdma_v0_regs
o Functions removed - __dw_regs()

Signed-off-by: Devendra K Verma <devverma@amd.com>
---
 drivers/dma/dw-edma/dw-edma-pcie.c       |  4 ++++
 drivers/dma/dw-edma/dw-hdma-v0-core.c    | 23 ++++++++++++++---------
 drivers/dma/dw-edma/dw-hdma-v0-debugfs.c | 17 ++++++-----------
 drivers/dma/dw-edma/dw-hdma-v0-regs.h    | 10 ----------
 include/linux/dma/edma.h                 |  1 +
 5 files changed, 25 insertions(+), 30 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
index 6295d01ba2f7..ca2a4be2f3a5 100644
--- a/drivers/dma/dw-edma/dw-edma-pcie.c
+++ b/drivers/dma/dw-edma/dw-edma-pcie.c
@@ -113,6 +113,7 @@ static const struct dw_edma_pcie_data snps_edda_data = {
 	.irqs				= 1,
 	.wr_ch_cnt			= 2,
 	.rd_ch_cnt			= 2,
+	.ch_sep_sz			= 256,
 };
 
 static const struct dw_edma_pcie_data xilinx_mdb_data = {
@@ -126,6 +127,7 @@ static const struct dw_edma_pcie_data xilinx_mdb_data = {
 	.irqs				= 1,
 	.wr_ch_cnt			= 8,
 	.rd_ch_cnt			= 8,
+	.ch_sep_sz			= 256,
 };
 
 static const struct dw_edma_pcie_data xilinx_cpm6_dma_data = {
@@ -139,6 +141,7 @@ static const struct dw_edma_pcie_data xilinx_cpm6_dma_data = {
 	.irqs				= 1,
 	.wr_ch_cnt			= 8,
 	.rd_ch_cnt			= 8,
+	.ch_sep_sz			= 512,
 };
 
 static void dw_edma_set_chan_region_offset(struct dw_edma_pcie_data *pdata,
@@ -443,6 +446,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
 	chip->nr_irqs = nr_irqs;
 	chip->ops = &dw_edma_pcie_plat_ops;
 	chip->cfg_non_ll = non_ll;
+	chip->ch_sep_sz = vsec_data->ch_sep_sz;
 
 	chip->ll_wr_cnt = vsec_data->wr_ch_cnt;
 	chip->ll_rd_cnt = vsec_data->rd_ch_cnt;
diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
index 632abb8b481c..3f27a93c4d8c 100644
--- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
@@ -23,18 +23,23 @@ enum dw_hdma_control {
 	DW_HDMA_V0_LLE					= BIT(9),
 };
 
-static inline struct dw_hdma_v0_regs __iomem *__dw_regs(struct dw_edma *dw)
-{
-	return dw->chip->reg_base;
-}
-
 static inline struct dw_hdma_v0_ch_regs __iomem *
 __dw_ch_regs(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch)
 {
-	if (dir == EDMA_DIR_WRITE)
-		return &(__dw_regs(dw)->ch[ch].wr);
-	else
-		return &(__dw_regs(dw)->ch[ch].rd);
+	u32 ch_base;
+
+	/*
+	 * For Write, the channel register index starts at
+	 * wr_base(ch_idx) = (2 * ch_idx) * ch_sep_sz
+	 *
+	 * For Read channel,
+	 * rd_base(ch_idx) = (2 * ch_idx + 1) * ch_sep_sz
+	 */
+	ch_base = 2 * ch;
+	if (dir == EDMA_DIR_READ)
+		ch_base += 1;
+
+	return dw->chip->reg_base + (ch_base * dw->chip->ch_sep_sz);
 }
 
 #define SET_CH_32(dw, dir, ch, name, value) \
diff --git a/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
index dcdc57fe976c..33128685bbd9 100644
--- a/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
@@ -13,22 +13,17 @@
 #include "dw-hdma-v0-regs.h"
 #include "dw-edma-core.h"
 
-#define REGS_ADDR(dw, name)						       \
-	({								       \
-		struct dw_hdma_v0_regs __iomem *__regs = (dw)->chip->reg_base; \
-									       \
-		(void __iomem *)&__regs->name;				       \
-	})
-
 #define REGS_CH_ADDR(dw, name, _dir, _ch)				       \
 	({								       \
-		struct dw_hdma_v0_ch_regs __iomem *__ch_regs;		       \
+		struct dw_hdma_v0_ch_regs __iomem *__ch_regs;                  \
+		off_t __off = (dw)->chip->ch_sep_sz;			       \
 									       \
-		if (_dir == EDMA_DIR_READ)				       \
-			__ch_regs = REGS_ADDR(dw, ch[_ch].rd);		       \
+		if ((_dir) == EDMA_DIR_READ)				       \
+			__off *= (2 * (_ch) + 1);			       \
 		else							       \
-			__ch_regs = REGS_ADDR(dw, ch[_ch].wr);		       \
+			__off *= (2 * (_ch));				       \
 									       \
+		__ch_regs = ((dw)->chip->reg_base + __off);		       \
 		(void __iomem *)&__ch_regs->name;			       \
 	})
 
diff --git a/drivers/dma/dw-edma/dw-hdma-v0-regs.h b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
index 7759ba9b4850..2475b8d96133 100644
--- a/drivers/dma/dw-edma/dw-hdma-v0-regs.h
+++ b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
@@ -84,16 +84,6 @@ struct dw_hdma_v0_ch_regs {
 		};
 	} msi_abort;
 	u32 msi_msgdata;			/* 0x00a8 */
-	u32 padding_2[21];			/* 0x00ac..0x00fc */
-} __packed;
-
-struct dw_hdma_v0_ch {
-	struct dw_hdma_v0_ch_regs wr;		/* 0x0000 */
-	struct dw_hdma_v0_ch_regs rd;		/* 0x0100 */
-} __packed;
-
-struct dw_hdma_v0_regs {
-	struct dw_hdma_v0_ch ch[HDMA_V0_MAX_NR_CH];	/* 0x0000..0x0fa8 */
 } __packed;
 
 struct dw_hdma_v0_lli {
diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
index 1fafd5b0e315..a6c5728f03d3 100644
--- a/include/linux/dma/edma.h
+++ b/include/linux/dma/edma.h
@@ -104,6 +104,7 @@ struct dw_edma_chip {
 
 	struct dw_edma		*dw;
 	bool			cfg_non_ll;
+	u32			ch_sep_sz;
 };
 
 /* Export to the platform drivers */
-- 
2.43.0

Re: [PATCH v1 3/3] dmaengine: dw-edma: Add changes to support Channel Separation

[Frank Li]

On Wed, Jul 22, 2026 at 04:46:40PM +0530, Devendra K Verma wrote:

Add Koichiro Den, who did many work with this edma driver recently

> Following changes are made:
> o In 'struct dw_hdma_v0_ch_regs', it is assumed the channel
>   separation as 256-bytes which is default, but if an IP is

channel register space size?

>   configured for a different size of channel separation then
>   user can retrieve it using the supported VSEC (0x6).
>   Modified the struct to work with the channel separation
>   supported by IP.
>   CPM6 supports channel separation, default is 512.


> o Changes in macros / functions where address of the channel
>   is accessed based on channel index and direction. It enables
>   the calculation of the channel reg base address based on
>   the selected channel separation.
> o Struct removed - dw_hdma_v0_ch, dw_hdma_v0_regs
> o Functions removed - __dw_regs()

Can you summary change and purpose? such as

Support difference channel register space size for difference IP. Previous
use fix default value 256, CMP6 support difference register space size,
which default value is 512.

Update channel register base address caluator method by use ch_space_sze
and remove unused dw_hdma_v0_ch, dw_hdma_v0_regs.

You can rephrase.

>
> Signed-off-by: Devendra K Verma <devverma@amd.com>
> ---
>  drivers/dma/dw-edma/dw-edma-pcie.c       |  4 ++++
>  drivers/dma/dw-edma/dw-hdma-v0-core.c    | 23 ++++++++++++++---------
>  drivers/dma/dw-edma/dw-hdma-v0-debugfs.c | 17 ++++++-----------
>  drivers/dma/dw-edma/dw-hdma-v0-regs.h    | 10 ----------
>  include/linux/dma/edma.h                 |  1 +
>  5 files changed, 25 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
> index 6295d01ba2f7..ca2a4be2f3a5 100644
> --- a/drivers/dma/dw-edma/dw-edma-pcie.c
> +++ b/drivers/dma/dw-edma/dw-edma-pcie.c
> @@ -113,6 +113,7 @@ static const struct dw_edma_pcie_data snps_edda_data = {
>  	.irqs				= 1,
>  	.wr_ch_cnt			= 2,
>  	.rd_ch_cnt			= 2,
> +	.ch_sep_sz			= 256,
>  };
>
>  static const struct dw_edma_pcie_data xilinx_mdb_data = {
> @@ -126,6 +127,7 @@ static const struct dw_edma_pcie_data xilinx_mdb_data = {
>  	.irqs				= 1,
>  	.wr_ch_cnt			= 8,
>  	.rd_ch_cnt			= 8,
> +	.ch_sep_sz			= 256,
>  };
>
>  static const struct dw_edma_pcie_data xilinx_cpm6_dma_data = {
> @@ -139,6 +141,7 @@ static const struct dw_edma_pcie_data xilinx_cpm6_dma_data = {
>  	.irqs				= 1,
>  	.wr_ch_cnt			= 8,
>  	.rd_ch_cnt			= 8,
> +	.ch_sep_sz			= 512,
>  };
>
>  static void dw_edma_set_chan_region_offset(struct dw_edma_pcie_data *pdata,
> @@ -443,6 +446,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
>  	chip->nr_irqs = nr_irqs;
>  	chip->ops = &dw_edma_pcie_plat_ops;
>  	chip->cfg_non_ll = non_ll;
> +	chip->ch_sep_sz = vsec_data->ch_sep_sz;


This blocks PCI endpoint DMA, this driver is not only used by this.
EPC controller will not set this value, so ch_sep_sz will be 0 for EPC
controller.

Frank

>
>  	chip->ll_wr_cnt = vsec_data->wr_ch_cnt;
>  	chip->ll_rd_cnt = vsec_data->rd_ch_cnt;
> diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> index 632abb8b481c..3f27a93c4d8c 100644
> --- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
> +++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> @@ -23,18 +23,23 @@ enum dw_hdma_control {
>  	DW_HDMA_V0_LLE					= BIT(9),
>  };
>
> -static inline struct dw_hdma_v0_regs __iomem *__dw_regs(struct dw_edma *dw)
> -{
> -	return dw->chip->reg_base;
> -}
> -
>  static inline struct dw_hdma_v0_ch_regs __iomem *
>  __dw_ch_regs(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch)
>  {
> -	if (dir == EDMA_DIR_WRITE)
> -		return &(__dw_regs(dw)->ch[ch].wr);
> -	else
> -		return &(__dw_regs(dw)->ch[ch].rd);
> +	u32 ch_base;
> +
> +	/*
> +	 * For Write, the channel register index starts at
> +	 * wr_base(ch_idx) = (2 * ch_idx) * ch_sep_sz
> +	 *
> +	 * For Read channel,
> +	 * rd_base(ch_idx) = (2 * ch_idx + 1) * ch_sep_sz
> +	 */
> +	ch_base = 2 * ch;
> +	if (dir == EDMA_DIR_READ)
> +		ch_base += 1;
> +
> +	return dw->chip->reg_base + (ch_base * dw->chip->ch_sep_sz);
>  }
>
>  #define SET_CH_32(dw, dir, ch, name, value) \
> diff --git a/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
> index dcdc57fe976c..33128685bbd9 100644
> --- a/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
> +++ b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
> @@ -13,22 +13,17 @@
>  #include "dw-hdma-v0-regs.h"
>  #include "dw-edma-core.h"
>
> -#define REGS_ADDR(dw, name)						       \
> -	({								       \
> -		struct dw_hdma_v0_regs __iomem *__regs = (dw)->chip->reg_base; \
> -									       \
> -		(void __iomem *)&__regs->name;				       \
> -	})
> -
>  #define REGS_CH_ADDR(dw, name, _dir, _ch)				       \
>  	({								       \
> -		struct dw_hdma_v0_ch_regs __iomem *__ch_regs;		       \
> +		struct dw_hdma_v0_ch_regs __iomem *__ch_regs;                  \
> +		off_t __off = (dw)->chip->ch_sep_sz;			       \
>  									       \
> -		if (_dir == EDMA_DIR_READ)				       \
> -			__ch_regs = REGS_ADDR(dw, ch[_ch].rd);		       \
> +		if ((_dir) == EDMA_DIR_READ)				       \
> +			__off *= (2 * (_ch) + 1);			       \
>  		else							       \
> -			__ch_regs = REGS_ADDR(dw, ch[_ch].wr);		       \
> +			__off *= (2 * (_ch));				       \
>  									       \
> +		__ch_regs = ((dw)->chip->reg_base + __off);		       \
>  		(void __iomem *)&__ch_regs->name;			       \
>  	})
>
> diff --git a/drivers/dma/dw-edma/dw-hdma-v0-regs.h b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
> index 7759ba9b4850..2475b8d96133 100644
> --- a/drivers/dma/dw-edma/dw-hdma-v0-regs.h
> +++ b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
> @@ -84,16 +84,6 @@ struct dw_hdma_v0_ch_regs {
>  		};
>  	} msi_abort;
>  	u32 msi_msgdata;			/* 0x00a8 */
> -	u32 padding_2[21];			/* 0x00ac..0x00fc */
> -} __packed;
> -
> -struct dw_hdma_v0_ch {
> -	struct dw_hdma_v0_ch_regs wr;		/* 0x0000 */
> -	struct dw_hdma_v0_ch_regs rd;		/* 0x0100 */
> -} __packed;
> -
> -struct dw_hdma_v0_regs {
> -	struct dw_hdma_v0_ch ch[HDMA_V0_MAX_NR_CH];	/* 0x0000..0x0fa8 */
>  } __packed;
>
>  struct dw_hdma_v0_lli {
> diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
> index 1fafd5b0e315..a6c5728f03d3 100644
> --- a/include/linux/dma/edma.h
> +++ b/include/linux/dma/edma.h
> @@ -104,6 +104,7 @@ struct dw_edma_chip {
>
>  	struct dw_edma		*dw;
>  	bool			cfg_non_ll;
> +	u32			ch_sep_sz;
>  };
>
>  /* Export to the platform drivers */
> --
> 2.43.0
>

Re: [PATCH v1 3/3] dmaengine: dw-edma: Add changes to support Channel Separation

[Frank Li]

On Thu, Jul 23, 2026 at 03:56:33PM +0530, Verma, Devendra wrote:
>
>
> On 22-Jul-26 20:52, Frank Li wrote:
> > On Wed, Jul 22, 2026 at 04:46:40PM +0530, Devendra K Verma wrote:
> >
> > Add Koichiro Den, who did many work with this edma driver recently
> >
>
> Sure, thanks!
>
> > > Following changes are made:
> > > o In 'struct dw_hdma_v0_ch_regs', it is assumed the channel
> > >    separation as 256-bytes which is default, but if an IP is
> >
> > channel register space size?
> >
> > >    configured for a different size of channel separation then
> > >    user can retrieve it using the supported VSEC (0x6).
> > >    Modified the struct to work with the channel separation
> > >    supported by IP.
> > >    CPM6 supports channel separation, default is 512.
> >
> >
> > > o Changes in macros / functions where address of the channel
> > >    is accessed based on channel index and direction. It enables
> > >    the calculation of the channel reg base address based on
> > >    the selected channel separation.
> > > o Struct removed - dw_hdma_v0_ch, dw_hdma_v0_regs
> > > o Functions removed - __dw_regs()
> >
> > Can you summary change and purpose? such as
> >
> > Support difference channel register space size for difference IP. Previous
> > use fix default value 256, CMP6 support difference register space size,
> > which default value is 512.
> >
> > Update channel register base address caluator method by use ch_space_sze
> > and remove unused dw_hdma_v0_ch, dw_hdma_v0_regs.
> >
> > You can rephrase.
> >
>
> Sure, I will rephrase this. Thank you for the suggestion!
>
> > >
> > > Signed-off-by: Devendra K Verma <devverma@amd.com>
> > > ---
> > >   drivers/dma/dw-edma/dw-edma-pcie.c       |  4 ++++
> > >   drivers/dma/dw-edma/dw-hdma-v0-core.c    | 23 ++++++++++++++---------
> > >   drivers/dma/dw-edma/dw-hdma-v0-debugfs.c | 17 ++++++-----------
> > >   drivers/dma/dw-edma/dw-hdma-v0-regs.h    | 10 ----------
> > >   include/linux/dma/edma.h                 |  1 +
> > >   5 files changed, 25 insertions(+), 30 deletions(-)
> > >
> > > diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c
> > > index 6295d01ba2f7..ca2a4be2f3a5 100644
> > > --- a/drivers/dma/dw-edma/dw-edma-pcie.c
> > > +++ b/drivers/dma/dw-edma/dw-edma-pcie.c
> > > @@ -113,6 +113,7 @@ static const struct dw_edma_pcie_data snps_edda_data = {
> > >   	.irqs				= 1,
> > >   	.wr_ch_cnt			= 2,
> > >   	.rd_ch_cnt			= 2,
> > > +	.ch_sep_sz			= 256,
> > >   };
> > >
> > >   static const struct dw_edma_pcie_data xilinx_mdb_data = {
> > > @@ -126,6 +127,7 @@ static const struct dw_edma_pcie_data xilinx_mdb_data = {
> > >   	.irqs				= 1,
> > >   	.wr_ch_cnt			= 8,
> > >   	.rd_ch_cnt			= 8,
> > > +	.ch_sep_sz			= 256,
> > >   };
> > >
> > >   static const struct dw_edma_pcie_data xilinx_cpm6_dma_data = {
> > > @@ -139,6 +141,7 @@ static const struct dw_edma_pcie_data xilinx_cpm6_dma_data = {
> > >   	.irqs				= 1,
> > >   	.wr_ch_cnt			= 8,
> > >   	.rd_ch_cnt			= 8,
> > > +	.ch_sep_sz			= 512,
> > >   };
> > >
> > >   static void dw_edma_set_chan_region_offset(struct dw_edma_pcie_data *pdata,
> > > @@ -443,6 +446,7 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev,
> > >   	chip->nr_irqs = nr_irqs;
> > >   	chip->ops = &dw_edma_pcie_plat_ops;
> > >   	chip->cfg_non_ll = non_ll;
> > > +	chip->ch_sep_sz = vsec_data->ch_sep_sz;
> >
> >
> > This blocks PCI endpoint DMA, this driver is not only used by this.
> > EPC controller will not set this value, so ch_sep_sz will be 0 for EPC
> > controller.
> >
> > Frank
> >
>
> The EPC driver is using the chip->reg_base + reg_offset for computing
> the final addresse and not using the register mappings. If the
> reg_offset are correct then this ch_sep_sz change will not affect the
> EPC driver.

show me, how work, both use below method to get channel register address

__dw_ch_regs () {
return dw->chip->reg_base + (ch_base * dw->chip->ch_sep_sz)
}

Frank

>
> > >
> > >   	chip->ll_wr_cnt = vsec_data->wr_ch_cnt;
> > >   	chip->ll_rd_cnt = vsec_data->rd_ch_cnt;
> > > diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> > > index 632abb8b481c..3f27a93c4d8c 100644
> > > --- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
> > > +++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> > > @@ -23,18 +23,23 @@ enum dw_hdma_control {
> > >   	DW_HDMA_V0_LLE					= BIT(9),
> > >   };
> > >
> > > -static inline struct dw_hdma_v0_regs __iomem *__dw_regs(struct dw_edma *dw)
> > > -{
> > > -	return dw->chip->reg_base;
> > > -}
> > > -
> > >   static inline struct dw_hdma_v0_ch_regs __iomem *
> > >   __dw_ch_regs(struct dw_edma *dw, enum dw_edma_dir dir, u16 ch)
> > >   {
> > > -	if (dir == EDMA_DIR_WRITE)
> > > -		return &(__dw_regs(dw)->ch[ch].wr);
> > > -	else
> > > -		return &(__dw_regs(dw)->ch[ch].rd);
> > > +	u32 ch_base;
> > > +
> > > +	/*
> > > +	 * For Write, the channel register index starts at
> > > +	 * wr_base(ch_idx) = (2 * ch_idx) * ch_sep_sz
> > > +	 *
> > > +	 * For Read channel,
> > > +	 * rd_base(ch_idx) = (2 * ch_idx + 1) * ch_sep_sz
> > > +	 */
> > > +	ch_base = 2 * ch;
> > > +	if (dir == EDMA_DIR_READ)
> > > +		ch_base += 1;
> > > +
> > > +	return dw->chip->reg_base + (ch_base * dw->chip->ch_sep_sz);
> > >   }
> > >
> > >   #define SET_CH_32(dw, dir, ch, name, value) \
> > > diff --git a/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
> > > index dcdc57fe976c..33128685bbd9 100644
> > > --- a/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
> > > +++ b/drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
> > > @@ -13,22 +13,17 @@
> > >   #include "dw-hdma-v0-regs.h"
> > >   #include "dw-edma-core.h"
> > >
> > > -#define REGS_ADDR(dw, name)						       \
> > > -	({								       \
> > > -		struct dw_hdma_v0_regs __iomem *__regs = (dw)->chip->reg_base; \
> > > -									       \
> > > -		(void __iomem *)&__regs->name;				       \
> > > -	})
> > > -
> > >   #define REGS_CH_ADDR(dw, name, _dir, _ch)				       \
> > >   	({								       \
> > > -		struct dw_hdma_v0_ch_regs __iomem *__ch_regs;		       \
> > > +		struct dw_hdma_v0_ch_regs __iomem *__ch_regs;                  \
> > > +		off_t __off = (dw)->chip->ch_sep_sz;			       \
> > >   									       \
> > > -		if (_dir == EDMA_DIR_READ)				       \
> > > -			__ch_regs = REGS_ADDR(dw, ch[_ch].rd);		       \
> > > +		if ((_dir) == EDMA_DIR_READ)				       \
> > > +			__off *= (2 * (_ch) + 1);			       \
> > >   		else							       \
> > > -			__ch_regs = REGS_ADDR(dw, ch[_ch].wr);		       \
> > > +			__off *= (2 * (_ch));				       \
> > >   									       \
> > > +		__ch_regs = ((dw)->chip->reg_base + __off);		       \
> > >   		(void __iomem *)&__ch_regs->name;			       \
> > >   	})
> > >
> > > diff --git a/drivers/dma/dw-edma/dw-hdma-v0-regs.h b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
> > > index 7759ba9b4850..2475b8d96133 100644
> > > --- a/drivers/dma/dw-edma/dw-hdma-v0-regs.h
> > > +++ b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
> > > @@ -84,16 +84,6 @@ struct dw_hdma_v0_ch_regs {
> > >   		};
> > >   	} msi_abort;
> > >   	u32 msi_msgdata;			/* 0x00a8 */
> > > -	u32 padding_2[21];			/* 0x00ac..0x00fc */
> > > -} __packed;
> > > -
> > > -struct dw_hdma_v0_ch {
> > > -	struct dw_hdma_v0_ch_regs wr;		/* 0x0000 */
> > > -	struct dw_hdma_v0_ch_regs rd;		/* 0x0100 */
> > > -} __packed;
> > > -
> > > -struct dw_hdma_v0_regs {
> > > -	struct dw_hdma_v0_ch ch[HDMA_V0_MAX_NR_CH];	/* 0x0000..0x0fa8 */
> > >   } __packed;
> > >
> > >   struct dw_hdma_v0_lli {
> > > diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
> > > index 1fafd5b0e315..a6c5728f03d3 100644
> > > --- a/include/linux/dma/edma.h
> > > +++ b/include/linux/dma/edma.h
> > > @@ -104,6 +104,7 @@ struct dw_edma_chip {
> > >
> > >   	struct dw_edma		*dw;
> > >   	bool			cfg_non_ll;
> > > +	u32			ch_sep_sz;
> > >   };
> > >
> > >   /* Export to the platform drivers */
> > > --
> > > 2.43.0
> > >
>