[PATCH] dmaengine: stm32-dma3: disable the active clock on removal

[PATCH] dmaengine: stm32-dma3: disable the active clock on removal

[Myeonghun Pak]

Probe enables the controller clock and runtime suspend disables it.
The remove callback only disables runtime PM, which does not itself
invoke runtime suspend. If the controller is still active, its clock
prepare and enable references therefore remain held after removal.

Remove the OF DMA provider and disable runtime PM, then release the
channel IRQs before disabling the clock. The IRQ handler reads controller
registers, so wait for it to finish rather than leaving IRQ release to
the managed cleanup that runs after remove returns.

Disable the clock only if the device is not already suspended, then mark
it suspended. This avoids a second clock disable for a runtime-suspended
device and also covers CONFIG_PM=n.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: f561ec8b2b33 ("dmaengine: Add STM32 DMA3 support")
Assisted-by: OpenAI:GPT-5.6
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
---
 drivers/dma/stm32/stm32-dma3.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/dma/stm32/stm32-dma3.c b/drivers/dma/stm32/stm32-dma3.c
index 4724e7fa0008e177160d085172cb89d6bc483c4f..b4d68be5a46b8aa1751dd32234d42f6e6b470335 100644
--- a/drivers/dma/stm32/stm32-dma3.c
+++ b/drivers/dma/stm32/stm32-dma3.c
@@ -1926,7 +1926,21 @@ static int stm32_dma3_probe(struct platform_device *pdev)
 
 static void stm32_dma3_remove(struct platform_device *pdev)
 {
+	struct stm32_dma3_ddata *ddata = platform_get_drvdata(pdev);
+	struct dma_chan *c;
+
+	of_dma_controller_free(pdev->dev.of_node);
 	pm_runtime_disable(&pdev->dev);
+
+	list_for_each_entry(c, &ddata->dma_dev.channels, device_node) {
+		struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
+
+		devm_free_irq(&pdev->dev, chan->irq, chan);
+	}
+
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		clk_disable_unprepare(ddata->clk);
+	pm_runtime_set_suspended(&pdev->dev);
 }
 
 static int stm32_dma3_runtime_suspend(struct device *dev)
-- 
2.53.0