[PATCH v26] dmaengine: qcom: bam_dma: free interrupt before the clock in error path

[PATCH v26] dmaengine: qcom: bam_dma: free interrupt before the clock in error path

[Bartosz Golaszewski]

The BAM interrupt is requested with a devres helper and so on error it's
freed after probe() returns. We disable the clock before freeing or
masking it so it may still fire and we may end up reading BAM registers
with clock disabled.

Stop using devres for interrupts as we free it in remove() manually
anyway. Add an appropriate label and free the interrupt before disabling
the clock in error path and in remove().

Cc: stable@vger.kernel.org
Fixes: e7c0fe2a5c84 ("dmaengine: add Qualcomm BAM dma driver")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260427-qcom-qce-cmd-descr-v16-0-945fd1cafbbc%40oss.qualcomm.com?part=2
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
This used to be part of the larger BAM DMA pipe locking series and never
got picked up despite months on the list. I'm resending it separately.
---
Changes in v26:
- Rebased on top of current linux-next to address conflicts
- Link to v25: https://patch.msgid.link/20261002-bam-dma-free-irq-v25-1-f39e01d19910@oss.qualcomm.com

Changes in v25:
- Don't touch remove(), it's not wrong in its current version
- Link to v24: https://patch.msgid.link/20260723-qcom-qce-cmd-descr-v24-0-4f87bb4d9938@oss.qualcomm.com
---
 drivers/dma/qcom/bam_dma.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 05a3b1f9e0c23dc5f861488fae03494867970523..a626746b5c93496e5c5e885b35a856d38c284448 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -1332,8 +1332,8 @@ static int bam_dma_probe(struct platform_device *pdev)
 	for (i = 0; i < bdev->num_channels; i++)
 		bam_channel_init(bdev, &bdev->channels[i], i);
 
-	ret = devm_request_irq(bdev->dev, bdev->irq, bam_dma_irq,
-			IRQF_TRIGGER_HIGH, "bam_dma", bdev);
+	ret = request_irq(bdev->irq, bam_dma_irq, IRQF_TRIGGER_HIGH,
+			  "bam_dma", bdev);
 	if (ret)
 		goto err_bam_channel_exit;
 
@@ -1366,7 +1366,7 @@ static int bam_dma_probe(struct platform_device *pdev)
 	ret = dma_async_device_register(&bdev->common);
 	if (ret) {
 		dev_err(bdev->dev, "failed to register dma async device\n");
-		goto err_bam_channel_exit;
+		goto err_free_irq;
 	}
 
 	ret = of_dma_controller_register(pdev->dev.of_node, bam_dma_xlate,
@@ -1385,6 +1385,8 @@ static int bam_dma_probe(struct platform_device *pdev)
 
 err_unregister_dma:
 	dma_async_device_unregister(&bdev->common);
+err_free_irq:
+	free_irq(bdev->irq, bdev);
 err_bam_channel_exit:
 	for (i = 0; i < bdev->num_channels; i++)
 		tasklet_kill(&bdev->channels[i].vc.task);
@@ -1410,7 +1412,7 @@ static void bam_dma_remove(struct platform_device *pdev)
 	/* mask all interrupts for this execution environment */
 	writel_relaxed(0, bam_addr(bdev, 0,  BAM_IRQ_SRCS_MSK_EE));
 
-	devm_free_irq(bdev->dev, bdev->irq, bdev);
+	free_irq(bdev->irq, bdev);
 
 	for (i = 0; i < bdev->num_channels; i++) {
 		bam_dma_terminate_all(&bdev->channels[i].vc.chan);

---
base-commit: bf1ee2bd5c2da8992f33c8950ef194aaff74ed6c
change-id: 20261002-bam-dma-free-irq-cac4b268c465

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Re: [PATCH v26] dmaengine: qcom: bam_dma: free interrupt before the clock in error path

[Vinod Koul]

Hey Bart,

On 06-10-26, 10:08, Bartosz Golaszewski wrote:
> The BAM interrupt is requested with a devres helper and so on error it's
> freed after probe() returns. We disable the clock before freeing or
> masking it so it may still fire and we may end up reading BAM registers
> with clock disabled.
> 
> Stop using devres for interrupts as we free it in remove() manually
> anyway. Add an appropriate label and free the interrupt before disabling
> the clock in error path and in remove().

This does not apply on current code, please rebase on dma/next

-- 
~Vinod