[PATCH RESEND 0/4] dma: dma-axi-dmac: fixes and improvements

[PATCH RESEND 0/4] dma: dma-axi-dmac: fixes and improvements

[Nuno Sá via B4 Relay]

This series adds some fixes to the DMA core with respect with cyclic
transfer and HW scatter gather.

It also adds some improvements. Most notably for allowing bigger that
32bits DMA masks so we do not have to rely on bounce buffers from
swiotlb.

---
Nuno Sá (4):
      dma: dma-axi-dmac: fix SW cyclic transfers
      dma: dma-axi-dmac: fix HW scatter-gather not looking at the queue
      dma: dma-axi-dmac: support bigger than 32bits addresses
      dma: dma-axi-dmac: simplify axi_dmac_parse_dt()

 drivers/dma/dma-axi-dmac.c | 48 +++++++++++++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 15 deletions(-)
---
base-commit: 3c018bf5a0ee3abe8d579d6a0dda616c3858d7b2
change-id: 20250520-dev-axi-dmac-fixes-41502e41d982
--

Thanks!
- Nuno Sá
-- 
Nuno Sá <nuno.sa@analog.com>

[PATCH RESEND 1/4] dma: dma-axi-dmac: fix SW cyclic transfers

[Nuno Sá via B4 Relay]

From: Nuno Sá <nuno.sa@analog.com>

If 'hw_cyclic' is false we should still be able to do cyclic transfers in
"software". That was not working for the case where 'desc->num_sgs' is 1
because 'chan->next_desc' is never set with the current desc which means
that the cyclic transfer only runs once and in the next SOT interrupt we
do nothing since vchan_next_desc() will return NULL.

Fix it by setting 'chan->next_desc' as soon as we get a new desc via
vchan_next_desc().

Fixes: 0e3b67b348b8 ("dmaengine: Add support for the Analog Devices AXI-DMAC DMA controller")
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 36943b0c6d603cbe38606b0d7bde02535f529a9a..2aa06f66624ba5749e7e7f24b55416f96064b82f 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -247,6 +247,7 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
 			return;
 		list_move_tail(&vdesc->node, &chan->active_descs);
 		desc = to_axi_dmac_desc(vdesc);
+		chan->next_desc = desc;
 	}
 	sg = &desc->sg[desc->num_submitted];
 
@@ -265,8 +266,6 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
 		else
 			chan->next_desc = NULL;
 		flags |= AXI_DMAC_FLAG_LAST;
-	} else {
-		chan->next_desc = desc;
 	}
 
 	sg->hw->id = axi_dmac_read(dmac, AXI_DMAC_REG_TRANSFER_ID);

-- 
2.50.1

[PATCH RESEND 2/4] dma: dma-axi-dmac: fix HW scatter-gather not looking at the queue

[Nuno Sá via B4 Relay]

From: Nuno Sá <nuno.sa@analog.com>

For HW scatter gather transfers we still need to look for the queue. The
HW is capable of queueing 3 concurrent transfers and if we try more than
that we'll get the submit queue full and should return. Otherwise, if we
go ahead and program the new transfer, we end up discarding it.

Fixes: e97dc7435972 ("dmaengine: axi-dmac: Add support for scatter-gather transfers")
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 2aa06f66624ba5749e7e7f24b55416f96064b82f..47d95d2d743b1b939ed0ec79ee29763843bcdc09 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -233,11 +233,9 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
 	unsigned int flags = 0;
 	unsigned int val;
 
-	if (!chan->hw_sg) {
-		val = axi_dmac_read(dmac, AXI_DMAC_REG_START_TRANSFER);
-		if (val) /* Queue is full, wait for the next SOT IRQ */
-			return;
-	}
+	val = axi_dmac_read(dmac, AXI_DMAC_REG_START_TRANSFER);
+	if (val) /* Queue is full, wait for the next SOT IRQ */
+		return;
 
 	desc = chan->next_desc;
 

-- 
2.50.1

[PATCH RESEND 3/4] dma: dma-axi-dmac: support bigger than 32bits addresses

[Nuno Sá via B4 Relay]

From: Nuno Sá <nuno.sa@analog.com>

In some supported platforms as ARCH_ZYNQMP, part of the memory is mapped
above 32bit addresses and since the DMA mask, by default, is set to 32bits,
we would need to rely on swiotlb (which incurs a performance penalty)
for the DMA mappings. Thus, we can write either the SRC or DEST high
addresses with 1's and read them back. The last bit set on the return
value will reflect the IP address bus width and so we can update the
device DMA mask accordingly.

While at it, support bigger that 32 bits transfers in IP without HW
scatter gather support.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 47d95d2d743b1b939ed0ec79ee29763843bcdc09..25717a6ea9848b6c591a3ab6adb27c6f21f002b9 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -69,7 +69,9 @@
 #define AXI_DMAC_REG_START_TRANSFER	0x408
 #define AXI_DMAC_REG_FLAGS		0x40c
 #define AXI_DMAC_REG_DEST_ADDRESS	0x410
+#define AXI_DMAC_REG_DEST_ADDRESS_HIGH	0x490
 #define AXI_DMAC_REG_SRC_ADDRESS	0x414
+#define AXI_DMAC_REG_SRC_ADDRESS_HIGH	0x494
 #define AXI_DMAC_REG_X_LENGTH		0x418
 #define AXI_DMAC_REG_Y_LENGTH		0x41c
 #define AXI_DMAC_REG_DEST_STRIDE	0x420
@@ -271,11 +273,14 @@ static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
 	if (!chan->hw_sg) {
 		if (axi_dmac_dest_is_mem(chan)) {
 			axi_dmac_write(dmac, AXI_DMAC_REG_DEST_ADDRESS, sg->hw->dest_addr);
+			axi_dmac_write(dmac, AXI_DMAC_REG_DEST_ADDRESS_HIGH,
+				       sg->hw->dest_addr >> 32);
 			axi_dmac_write(dmac, AXI_DMAC_REG_DEST_STRIDE, sg->hw->dst_stride);
 		}
 
 		if (axi_dmac_src_is_mem(chan)) {
 			axi_dmac_write(dmac, AXI_DMAC_REG_SRC_ADDRESS, sg->hw->src_addr);
+			axi_dmac_write(dmac, AXI_DMAC_REG_SRC_ADDRESS_HIGH, sg->hw->src_addr >> 32);
 			axi_dmac_write(dmac, AXI_DMAC_REG_SRC_STRIDE, sg->hw->src_stride);
 		}
 	}
@@ -990,6 +995,9 @@ static int axi_dmac_read_chan_config(struct device *dev, struct axi_dmac *dmac)
 static int axi_dmac_detect_caps(struct axi_dmac *dmac, unsigned int version)
 {
 	struct axi_dmac_chan *chan = &dmac->chan;
+	struct device *dev = dmac->dma_dev.dev;
+	u32 mask;
+	int ret;
 
 	axi_dmac_write(dmac, AXI_DMAC_REG_FLAGS, AXI_DMAC_FLAG_CYCLIC);
 	if (axi_dmac_read(dmac, AXI_DMAC_REG_FLAGS) == AXI_DMAC_FLAG_CYCLIC)
@@ -1024,6 +1032,22 @@ static int axi_dmac_detect_caps(struct axi_dmac *dmac, unsigned int version)
 		return -ENODEV;
 	}
 
+	if (axi_dmac_dest_is_mem(chan)) {
+		axi_dmac_write(dmac, AXI_DMAC_REG_DEST_ADDRESS_HIGH, 0xffffffff);
+		mask = axi_dmac_read(dmac, AXI_DMAC_REG_DEST_ADDRESS_HIGH);
+	} else {
+		axi_dmac_write(dmac, AXI_DMAC_REG_SRC_ADDRESS_HIGH, 0xffffffff);
+		mask = axi_dmac_read(dmac, AXI_DMAC_REG_SRC_ADDRESS_HIGH);
+	}
+
+	mask = 32 + fls(mask);
+
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(mask));
+	if (ret) {
+		dev_err(dev, "DMA mask set error %d\n", ret);
+		return ret;
+	}
+
 	if (version >= ADI_AXI_PCORE_VER(4, 2, 'a'))
 		chan->hw_partial_xfer = true;
 

-- 
2.50.1

[PATCH RESEND 4/4] dma: dma-axi-dmac: simplify axi_dmac_parse_dt()

[Nuno Sá via B4 Relay]

From: Nuno Sá <nuno.sa@analog.com>

Simplify axi_dmac_parse_dt() by using the cleanup device_node class for
automatically releasing the of_node reference when going out of scope.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/dma/dma-axi-dmac.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 25717a6ea9848b6c591a3ab6adb27c6f21f002b9..035fc703506977ad59fd0b6ee8a8e5858d2c120e 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/bitfield.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
@@ -927,22 +928,18 @@ static int axi_dmac_parse_chan_dt(struct device_node *of_chan,
 
 static int axi_dmac_parse_dt(struct device *dev, struct axi_dmac *dmac)
 {
-	struct device_node *of_channels, *of_chan;
 	int ret;
 
-	of_channels = of_get_child_by_name(dev->of_node, "adi,channels");
+	struct device_node *of_channels __free(device_node) = of_get_child_by_name(dev->of_node,
+										   "adi,channels");
 	if (of_channels == NULL)
 		return -ENODEV;
 
-	for_each_child_of_node(of_channels, of_chan) {
+	for_each_child_of_node_scoped(of_channels, of_chan) {
 		ret = axi_dmac_parse_chan_dt(of_chan, &dmac->chan);
-		if (ret) {
-			of_node_put(of_chan);
-			of_node_put(of_channels);
+		if (ret)
 			return -EINVAL;
-		}
 	}
-	of_node_put(of_channels);
 
 	return 0;
 }

-- 
2.50.1

[PATCH RESEND 0/4] dma: dma-axi-dmac: fixes and improvements

[Nuno Sá via B4 Relay]

This series adds some fixes to the DMA core with respect with cyclic
transfer and HW scatter gather.

It also adds some improvements. Most notably for allowing bigger that
32bits DMA masks so we do not have to rely on bounce buffers from
swiotlb.

---
Nuno Sá (4):
      dma: dma-axi-dmac: fix SW cyclic transfers
      dma: dma-axi-dmac: fix HW scatter-gather not looking at the queue
      dma: dma-axi-dmac: support bigger than 32bits addresses
      dma: dma-axi-dmac: simplify axi_dmac_parse_dt()

 drivers/dma/dma-axi-dmac.c | 48 +++++++++++++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 15 deletions(-)
---
base-commit: 3c018bf5a0ee3abe8d579d6a0dda616c3858d7b2
change-id: 20250520-dev-axi-dmac-fixes-41502e41d982
--

Thanks!
- Nuno Sá
-- 
Nuno Sá <nuno.sa@analog.com>

[PATCH RESEND 0/4] dma: dma-axi-dmac: fixes and improvements

[Nuno Sá via B4 Relay]

This series adds some fixes to the DMA core with respect with cyclic
transfer and HW scatter gather.

It also adds some improvements. Most notably for allowing bigger that
32bits DMA masks so we do not have to rely on bounce buffers from
swiotlb.

---
Nuno Sá (4):
      dma: dma-axi-dmac: fix SW cyclic transfers
      dma: dma-axi-dmac: fix HW scatter-gather not looking at the queue
      dma: dma-axi-dmac: support bigger than 32bits addresses
      dma: dma-axi-dmac: simplify axi_dmac_parse_dt()

 drivers/dma/dma-axi-dmac.c | 48 +++++++++++++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 15 deletions(-)
---
base-commit: 3c018bf5a0ee3abe8d579d6a0dda616c3858d7b2
change-id: 20250520-dev-axi-dmac-fixes-41502e41d982
--

Thanks!
- Nuno Sá
-- 
Nuno Sá <nuno.sa@analog.com>

Re: [PATCH RESEND 0/4] dma: dma-axi-dmac: fixes and improvements

[Nuno Sá]

On Fri, 2025-06-27 at 16:00 +0100, Nuno Sá via B4 Relay wrote:
> This series adds some fixes to the DMA core with respect with cyclic
> transfer and HW scatter gather.
> 
> It also adds some improvements. Most notably for allowing bigger that
> 32bits DMA masks so we do not have to rely on bounce buffers from
> swiotlb.
> 
> ---

Hi Vinod,

Any chance to look at this? Just trying a ping before resending again.

Thanks!
- Nuno Sá
 
> Nuno Sá (4):
>       dma: dma-axi-dmac: fix SW cyclic transfers
>       dma: dma-axi-dmac: fix HW scatter-gather not looking at the queue
>       dma: dma-axi-dmac: support bigger than 32bits addresses
>       dma: dma-axi-dmac: simplify axi_dmac_parse_dt()
> 
>  drivers/dma/dma-axi-dmac.c | 48 +++++++++++++++++++++++++++++++--------------
> -
>  1 file changed, 33 insertions(+), 15 deletions(-)
> ---
> base-commit: 3c018bf5a0ee3abe8d579d6a0dda616c3858d7b2
> change-id: 20250520-dev-axi-dmac-fixes-41502e41d982
> --
> 
> Thanks!
> - Nuno Sá

[PATCH RESEND 0/4] dma: dma-axi-dmac: fixes and improvements

[Nuno Sá via B4 Relay]

This series adds some fixes to the DMA core with respect with cyclic
transfer and HW scatter gather.

It also adds some improvements. Most notably for allowing bigger that
32bits DMA masks so we do not have to rely on bounce buffers from
swiotlb.

---
Nuno Sá (4):
      dma: dma-axi-dmac: fix SW cyclic transfers
      dma: dma-axi-dmac: fix HW scatter-gather not looking at the queue
      dma: dma-axi-dmac: support bigger than 32bits addresses
      dma: dma-axi-dmac: simplify axi_dmac_parse_dt()

 drivers/dma/dma-axi-dmac.c | 48 +++++++++++++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 15 deletions(-)
---
base-commit: 3c018bf5a0ee3abe8d579d6a0dda616c3858d7b2
change-id: 20250520-dev-axi-dmac-fixes-41502e41d982
--

Thanks!
- Nuno Sá
-- 
Nuno Sá <nuno.sa@analog.com>