[PATCH V2 0/8] dmaengine: zynqmp_dma: Fix error paths and follow-up cleanups

[PATCH V2 0/8] dmaengine: zynqmp_dma: Fix error paths and follow-up cleanups

[Golla Nagendra]

This series fixes error-path cleanup issues in alloc/probe flows and
applies follow-up cleanups in the Xilinx ZynqMP DMA driver.

This series fixes error-path cleanup issues in alloc/probe flows and
applies follow-up cleanups in the Xilinx ZynqMP DMA driver.

Patch 1 fixes runtime PM rollback when sw_desc_pool allocation fails
after pm_runtime_resume_and_get().

Patch 2 frees sw_desc_pool when desc_pool_v allocation fails after
sw_desc_pool has already been allocated.

Patch 3 fixes channel probe/remove error handling by preserving
platform_get_irq() errors, initializing/staging chan->irq safely, and
registering the channel node only after IRQ setup succeeds.

Patch 4 updates stale kerneldoc comments to match current behavior.

Patch 5 applies minor whitespace formatting cleanup in
zynqmp_dma_chan_probe().

Patch 6 switches dma-coherent detection to of_dma_is_coherent() instead
of parsing the common device-tree property directly.

Patch 7 rejects zero-length memcpy preparations and documents the return
behavior.

Patch 8 removes an unused define and drops a duplicate interrupt enable
bit from the default IRQ mask.

Changes in v2:
- Split the previous alloc_chan_resources cleanup into two focused
  patches:
  - Patch 1 for runtime PM rollback on sw_desc_pool allocation failure.
  - Patch 2 for sw_desc_pool release on desc_pool_v allocation failure.
- Reworked channel probe failure teardown to use the existing
  free_chan_resources goto path instead of adding direct tasklet kill in
  the outer probe failure block.
- Kept the whitespace-only change as a standalone patch and moved
  dma-coherent handling to a dedicated patch using
  of_dma_is_coherent().
- Updated commit descriptions to match exact per-patch behavior.

Golla Nagendra (8):
  dmaengine: zynqmp_dma: Fix PM rollback on sw_desc_pool alloc failure
  dmaengine: zynqmp_dma: Free sw_desc_pool on desc_pool_v alloc failure
  dmaengine: zynqmp_dma: Fix chan probe/remove error handling
  dmaengine: zynqmp_dma: Fix stale kerneldoc comments
  dmaengine: zynqmp_dma: Fix minor whitespace
  dmaengine: zynqmp_dma: Use of_dma_is_coherent for dma-coherent
  dmaengine: zynqmp_dma: Reject zero-length memcpy transfers
  dmaengine: zynqmp_dma: Remove unused define and duplicate IRQ bit

 drivers/dma/xilinx/zynqmp_dma.c | 73 +++++++++++++++++++++------------
 1 file changed, 46 insertions(+), 27 deletions(-)

-- 
2.44.4

[PATCH V2 1/8] dmaengine: zynqmp_dma: Fix PM rollback on sw_desc_pool alloc failure

[Golla Nagendra]

If sw_desc_pool allocation fails after pm_runtime_resume_and_get()
succeeds in zynqmp_dma_alloc_chan_resources(), the error path returns
without dropping the runtime PM reference.

Route that failure path through err_pm so the runtime PM reference is
balanced before returning the error.

Fixes: 8982d48af36d ("dmaengine: zynqmp_dma: Fix PM reference leak in zynqmp_dma_alloc_chan_resourc()")
Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
---
changes in v2:
- Reworked the patch so sw_desc_pool allocation failure goes through
  err_pm, ensuring the runtime PM reference is dropped before returning
  the error
- Updated commit description to match the new behavior
---
 drivers/dma/xilinx/zynqmp_dma.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index f6a812e49ddc..9f1e69700dd0 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -483,8 +483,10 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
 		return ret;
 
 	chan->sw_desc_pool = kzalloc_objs(*desc, ZYNQMP_DMA_NUM_DESCS);
-	if (!chan->sw_desc_pool)
-		return -ENOMEM;
+	if (!chan->sw_desc_pool) {
+		ret = -ENOMEM;
+		goto err_pm;
+	}
 
 	chan->idle = true;
 	chan->desc_free_cnt = ZYNQMP_DMA_NUM_DESCS;
@@ -516,6 +518,10 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
 	}
 
 	return ZYNQMP_DMA_NUM_DESCS;
+
+err_pm:
+	pm_runtime_put_autosuspend(chan->dev);
+	return ret;
 }
 
 /**
-- 
2.44.4

[PATCH V2 2/8] dmaengine: zynqmp_dma: Free sw_desc_pool on desc_pool_v alloc failure

[Golla Nagendra]

In zynqmp_dma_alloc_chan_resources(), sw_desc_pool is allocated before
desc_pool_v. If dma_alloc_coherent() for desc_pool_v fails, the function
currently exits through the runtime PM rollback path but leaves the
already allocated sw_desc_pool behind.

Add a dedicated err_free_sw_desc_pool label for the desc_pool_v failure
path, free sw_desc_pool there, then fall through to err_pm for
pm_runtime_put_autosuspend().

This keeps the error unwind symmetric and avoids leaking the software
descriptor pool on coherent descriptor allocation failure.

Fixes: b0cc417c1637 ("dmaengine: Add Xilinx zynqmp dma engine driver support")
Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
---
changes in v2:
- Split this cleanup from the previous combined alloc_chan_resources patch
- Added err_free_sw_desc_pool label for desc_pool_v allocation failure,
  freeing sw_desc_pool before falling through to err_pm
- Updated commit description to match the exact cleanup path
---
 drivers/dma/xilinx/zynqmp_dma.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index 9f1e69700dd0..b7c561280694 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -504,8 +504,10 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
 					       (2 * ZYNQMP_DMA_DESC_SIZE(chan) *
 					       ZYNQMP_DMA_NUM_DESCS),
 					       &chan->desc_pool_p, GFP_KERNEL);
-	if (!chan->desc_pool_v)
-		return -ENOMEM;
+	if (!chan->desc_pool_v) {
+		ret = -ENOMEM;
+		goto err_free_sw_desc_pool;
+	}
 
 	for (i = 0; i < ZYNQMP_DMA_NUM_DESCS; i++) {
 		desc = chan->sw_desc_pool + i;
@@ -519,6 +521,9 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
 
 	return ZYNQMP_DMA_NUM_DESCS;
 
+err_free_sw_desc_pool:
+	kfree(chan->sw_desc_pool);
+	chan->sw_desc_pool = NULL;
 err_pm:
 	pm_runtime_put_autosuspend(chan->dev);
 	return ret;
-- 
2.44.4

[PATCH V2 3/8] dmaengine: zynqmp_dma: Fix chan probe/remove error handling

[Golla Nagendra]

Keep the real platform_get_irq() error by returning ret directly, stage
IRQ setup via a local ret variable, and assign chan->irq only after
devm_request_irq() succeeds.

Initialize chan->irq to -1 and initialize chan->common.device_node
before it may be touched by teardown. In channel remove, free IRQ only
for valid IRQ numbers and delete the channel node only when it is linked.

Register the channel node only after successful IRQ setup. On channel
probe failure in zynqmp_dma_probe(), route cleanup through the existing
free_chan_resources teardown path.

Fixes: b0cc417c1637 ("dmaengine: Add Xilinx zynqmp dma engine driver support")
Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
---
changes in v2:
- Reworked probe failure cleanup to use the existing free_chan_resources teardown path instead of adding direct tasklet kill in the outer probe failure block
- Kept IRQ/list initialization and channel registration ordering fixes in this patch
---
 drivers/dma/xilinx/zynqmp_dma.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index b7c561280694..22b517c57003 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -205,7 +205,7 @@ struct zynqmp_dma_desc_sw {
  * @desc_pool_p: Physical allocated descriptor base
  * @desc_free_cnt: Descriptor available count
  * @dev: The dma device
- * @irq: Channel IRQ
+ * @irq: Linux IRQ number, or -1 when not registered
  * @is_dmacoherent: Tells whether dma operations are coherent or not
  * @tasklet: Cleanup work after irq
  * @idle : Channel status;
@@ -896,10 +896,11 @@ static void zynqmp_dma_chan_remove(struct zynqmp_dma_chan *chan)
 	if (!chan)
 		return;
 
-	if (chan->irq)
+	if (chan->irq >= 0)
 		devm_free_irq(chan->zdev->dev, chan->irq, chan);
 	tasklet_kill(&chan->tasklet);
-	list_del(&chan->common.device_node);
+	if (!list_empty(&chan->common.device_node))
+		list_del(&chan->common.device_node);
 }
 
 /**
@@ -915,13 +916,14 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
 	struct zynqmp_dma_chan *chan;
 	struct device_node *node = pdev->dev.of_node;
 	const struct zynqmp_dma_config *match_data;
-	int err;
+	int err, ret;
 
 	chan = devm_kzalloc(zdev->dev, sizeof(*chan), GFP_KERNEL);
 	if (!chan)
 		return -ENOMEM;
 	chan->dev = zdev->dev;
 	chan->zdev = zdev;
+	chan->irq = -1;
 
 	chan->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(chan->regs))
@@ -954,22 +956,26 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
 	INIT_LIST_HEAD(&chan->pending_list);
 	INIT_LIST_HEAD(&chan->done_list);
 	INIT_LIST_HEAD(&chan->free_list);
+	INIT_LIST_HEAD(&chan->common.device_node);
 
 	dma_cookie_init(&chan->common);
 	chan->common.device = &zdev->common;
-	list_add_tail(&chan->common.device_node, &zdev->common.channels);
-
 	zynqmp_dma_init(chan);
-	chan->irq = platform_get_irq(pdev, 0);
-	if (chan->irq < 0)
-		return -ENXIO;
-	err = devm_request_irq(&pdev->dev, chan->irq, zynqmp_dma_irq_handler, 0,
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		return ret;
+
+	err = devm_request_irq(&pdev->dev, ret, zynqmp_dma_irq_handler, 0,
 			       "zynqmp-dma", chan);
 	if (err)
 		return err;
 
+	chan->irq = ret;
+
 	chan->desc_size = sizeof(struct zynqmp_dma_desc_ll);
 	chan->idle = true;
+	list_add_tail(&chan->common.device_node, &zdev->common.channels);
+
 	return 0;
 }
 
@@ -1134,7 +1140,7 @@ static int zynqmp_dma_probe(struct platform_device *pdev)
 	ret = zynqmp_dma_chan_probe(zdev, pdev);
 	if (ret) {
 		dev_err_probe(&pdev->dev, ret, "Probing channel failed\n");
-		goto err_disable_pm;
+		goto free_chan_resources;
 	}
 
 	p->dst_addr_widths = BIT(zdev->chan->bus_width / 8);
-- 
2.44.4

[PATCH V2 4/8] dmaengine: zynqmp_dma: Fix stale kerneldoc comments

[Golla Nagendra]

Correct kerneldoc comments that no longer matched the code.

Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
Changes in V2:
- No Change
---
 drivers/dma/xilinx/zynqmp_dma.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index 22b517c57003..a2fbefbb43b6 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -208,7 +208,7 @@ struct zynqmp_dma_desc_sw {
  * @irq: Linux IRQ number, or -1 when not registered
  * @is_dmacoherent: Tells whether dma operations are coherent or not
  * @tasklet: Cleanup work after irq
- * @idle : Channel status;
+ * @idle: Channel status
  * @desc_size: Size of the low level descriptor
  * @err: Channel has errors
  * @bus_width: Bus width
@@ -435,7 +435,7 @@ zynqmp_dma_get_descriptor(struct zynqmp_dma_chan *chan)
 }
 
 /**
- * zynqmp_dma_free_descriptor - Issue pending transactions
+ * zynqmp_dma_free_descriptor - Return a descriptor to the free pool
  * @chan: ZynqMP DMA channel pointer
  * @sdesc: Transaction descriptor pointer
  */
@@ -617,7 +617,6 @@ static void zynqmp_dma_start_transfer(struct zynqmp_dma_chan *chan)
 	zynqmp_dma_start(chan);
 }
 
-
 /**
  * zynqmp_dma_chan_desc_cleanup - Cleanup the completed descriptors
  * @chan: ZynqMP DMA channel
@@ -908,7 +907,7 @@ static void zynqmp_dma_chan_remove(struct zynqmp_dma_chan *chan)
  * @zdev: Driver specific device structure
  * @pdev: Pointer to the platform_device structure
  *
- * Return: '0' on success and failure value on error
+ * Return: 0 on success and negative error code on failure
  */
 static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
 			   struct platform_device *pdev)
@@ -1042,11 +1041,11 @@ static int __maybe_unused zynqmp_dma_runtime_suspend(struct device *dev)
 }
 
 /**
- * zynqmp_dma_runtime_resume - Runtime suspend method for the driver
+ * zynqmp_dma_runtime_resume - Runtime resume method for the driver
  * @dev:	Address of the device structure
  *
- * Put the driver into low power mode.
- * Return: 0 always
+ * Enable device clocks.
+ * Return: 0 on success and failure value on error
  */
 static int __maybe_unused zynqmp_dma_runtime_resume(struct device *dev)
 {
-- 
2.44.4

[PATCH V2 5/8] dmaengine: zynqmp_dma: Fix minor whitespace

[Golla Nagendra]

Add a blank line in zynqmp_dma_chan_probe() to separate channel
initialization from hardware setup.

Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
---
changes in v2:
- Split whitespace-only cleanup from the kerneldoc patch into this dedicated patch
---
 drivers/dma/xilinx/zynqmp_dma.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index a2fbefbb43b6..5e81e0d950e8 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -959,6 +959,7 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
 
 	dma_cookie_init(&chan->common);
 	chan->common.device = &zdev->common;
+
 	zynqmp_dma_init(chan);
 	ret = platform_get_irq(pdev, 0);
 	if (ret < 0)
-- 
2.44.4

[PATCH V2 6/8] dmaengine: zynqmp_dma: Use of_dma_is_coherent for dma-coherent

[Golla Nagendra]

Use of_dma_is_coherent() instead of parsing the common dma-coherent
device-tree property directly.

Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
---
changes in v2:
- Added as a dedicated patch based on review feedback to use of_dma_is_coherent() 
  for the common dma-coherent property
---
 drivers/dma/xilinx/zynqmp_dma.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index 5e81e0d950e8..194abfd6cb25 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -12,6 +12,7 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/of_dma.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
@@ -947,7 +948,7 @@ static int zynqmp_dma_chan_probe(struct zynqmp_dma_device *zdev,
 	if (match_data)
 		chan->irq_offset = match_data->offset;
 
-	chan->is_dmacoherent =  of_property_read_bool(node, "dma-coherent");
+	chan->is_dmacoherent = of_dma_is_coherent(node);
 	zdev->chan = chan;
 	tasklet_setup(&chan->tasklet, zynqmp_dma_do_tasklet);
 	spin_lock_init(&chan->lock);
-- 
2.44.4

[PATCH V2 7/8] dmaengine: zynqmp_dma: Reject zero-length memcpy transfers

[Golla Nagendra]

Zero-length prep_memcpy() needlessly consumed a descriptor slot. Reject
zero-length memcpy at prep time and document the behaviour.

Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
---
Changes in V2:
- No change
---
 drivers/dma/xilinx/zynqmp_dma.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index 194abfd6cb25..921d3d9f6ed6 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -837,7 +837,8 @@ static void zynqmp_dma_synchronize(struct dma_chan *dchan)
  * @len: Transfer length
  * @flags: transfer ack flags
  *
- * Return: Async transaction descriptor on success and NULL on failure
+ * Return: Async transaction descriptor on success and NULL on failure or
+ *	   zero length transfer
  */
 static struct dma_async_tx_descriptor *zynqmp_dma_prep_memcpy(
 				struct dma_chan *dchan, dma_addr_t dma_dst,
@@ -852,6 +853,9 @@ static struct dma_async_tx_descriptor *zynqmp_dma_prep_memcpy(
 
 	chan = to_chan(dchan);
 
+	if (!len)
+		return NULL;
+
 	desc_cnt = DIV_ROUND_UP(len, ZYNQMP_DMA_MAX_TRANS_LEN);
 
 	spin_lock_irqsave(&chan->lock, irqflags);
-- 
2.44.4

[PATCH V2 8/8] dmaengine: zynqmp_dma: Remove unused define and duplicate IRQ bit

[Golla Nagendra]

Remove the unused ZYNQMP_DMA_SRC_ISSUE_RST_VAL define.
ZYNQMP_DMA_DST_DSCR_DONE was also set twice in the default interrupt enable
mask; remove the duplicate bit.

Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
Changesin V2:
- No Change
---
 drivers/dma/xilinx/zynqmp_dma.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
index 921d3d9f6ed6..b2a9b60f3052 100644
--- a/drivers/dma/xilinx/zynqmp_dma.c
+++ b/drivers/dma/xilinx/zynqmp_dma.c
@@ -113,8 +113,7 @@
 #define ZYNQMP_DMA_INT_DONE	(ZYNQMP_DMA_DONE | ZYNQMP_DMA_DST_DSCR_DONE)
 #define ZYNQMP_DMA_INT_EN_DEFAULT_MASK	(ZYNQMP_DMA_INT_DONE | \
 					ZYNQMP_DMA_INT_ERR | \
-					ZYNQMP_DMA_INT_OVRFL | \
-					ZYNQMP_DMA_DST_DSCR_DONE)
+					ZYNQMP_DMA_INT_OVRFL)
 
 /* Max number of descriptors per channel */
 #define ZYNQMP_DMA_NUM_DESCS	32
@@ -129,8 +128,6 @@
 /* Reset values for data attributes */
 #define ZYNQMP_DMA_AXCACHE_VAL		0xF
 
-#define ZYNQMP_DMA_SRC_ISSUE_RST_VAL	0x1F
-
 #define ZYNQMP_DMA_IDS_DEFAULT_MASK	0xFFF
 
 /* Bus width in bits */
-- 
2.44.4

Re: [PATCH V2 1/8] dmaengine: zynqmp_dma: Fix PM rollback on sw_desc_pool alloc failure

[Frank Li]

On Fri, Aug 14, 2026 at 10:26:09AM +0530, Golla Nagendra wrote:
> If sw_desc_pool allocation fails after pm_runtime_resume_and_get()
> succeeds in zynqmp_dma_alloc_chan_resources(), the error path returns
> without dropping the runtime PM reference.
>
> Route that failure path through err_pm so the runtime PM reference is
> balanced before returning the error.
>
> Fixes: 8982d48af36d ("dmaengine: zynqmp_dma: Fix PM reference leak in zynqmp_dma_alloc_chan_resourc()")
> Signed-off-by: Golla Nagendra <nagendra.golla@amd.com>
> ---

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

> changes in v2:
> - Reworked the patch so sw_desc_pool allocation failure goes through
>   err_pm, ensuring the runtime PM reference is dropped before returning
>   the error
> - Updated commit description to match the new behavior
> ---
>  drivers/dma/xilinx/zynqmp_dma.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/xilinx/zynqmp_dma.c b/drivers/dma/xilinx/zynqmp_dma.c
> index f6a812e49ddc..9f1e69700dd0 100644
> --- a/drivers/dma/xilinx/zynqmp_dma.c
> +++ b/drivers/dma/xilinx/zynqmp_dma.c
> @@ -483,8 +483,10 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
>  		return ret;
>
>  	chan->sw_desc_pool = kzalloc_objs(*desc, ZYNQMP_DMA_NUM_DESCS);
> -	if (!chan->sw_desc_pool)
> -		return -ENOMEM;
> +	if (!chan->sw_desc_pool) {
> +		ret = -ENOMEM;
> +		goto err_pm;
> +	}
>
>  	chan->idle = true;
>  	chan->desc_free_cnt = ZYNQMP_DMA_NUM_DESCS;
> @@ -516,6 +518,10 @@ static int zynqmp_dma_alloc_chan_resources(struct dma_chan *dchan)
>  	}
>
>  	return ZYNQMP_DMA_NUM_DESCS;
> +
> +err_pm:
> +	pm_runtime_put_autosuspend(chan->dev);
> +	return ret;
>  }
>
>  /**
> --
> 2.44.4
>