[PATCH v2] dmaengine: mediatek: hsdma: fix runtime PM leak on init failure

[Myeonghun Pak]

mtk_hsdma_hw_init() enables runtime PM and gets a runtime PM reference
before enabling the HSDMA clock. It currently ignores failures from
pm_runtime_get_sync(); if runtime resume fails, the usage count remains
held. If clk_prepare_enable() then fails, the usage count remains held.

Use devm_pm_runtime_enable() to manage runtime PM enablement, and use
pm_runtime_resume_and_get() so resume failures do not leak the usage count.
If clk_prepare_enable() fails after a successful runtime resume, drop the
runtime PM reference before returning.

The probe path also ignores the return value from mtk_hsdma_hw_init(), so a
failed hardware init can continue as a successful probe. Propagate
mtk_hsdma_hw_init() failures from probe, while keeping a separate unwind
label so mtk_hsdma_hw_deinit() is only called after hardware init succeeds.

Fixes: 548c4597e984 ("dmaengine: mediatek: Add MediaTek High-Speed DMA controller for MT7622 and MT7623 SoC")
Co-developed-by: Ijae Kim <ae878000@xxxxxxxxx>
Signed-off-by: Ijae Kim <ae878000@xxxxxxxxx>
Signed-off-by: Myeonghun Pak <mhun512@xxxxxxxxx>

---
Changes in v2:
- Use devm_pm_runtime_enable() for runtime PM enablement.
- Drop manual pm_runtime_disable() calls from init/deinit paths.

 drivers/dma/mediatek/mtk-hsdma.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/mediatek/mtk-hsdma.c b/drivers/dma/mediatek/mtk-hsdma.c
index a43412ff5e..27cb370106 100644
--- a/drivers/dma/mediatek/mtk-hsdma.c
+++ b/drivers/dma/mediatek/mtk-hsdma.c
@@ -848,17 +848,27 @@ static int mtk_hsdma_hw_init(struct mtk_hsdma_device *hsdma)
 {
 	int err;
 
-	pm_runtime_enable(hsdma2dev(hsdma));
-	pm_runtime_get_sync(hsdma2dev(hsdma));
+	err = devm_pm_runtime_enable(hsdma2dev(hsdma));
+	if (err)
+		return err;
+
+	err = pm_runtime_resume_and_get(hsdma2dev(hsdma));
+	if (err < 0)
+		return err;
 
 	err = clk_prepare_enable(hsdma->clk);
 	if (err)
-		return err;
+		goto err_put_pm;
 
 	mtk_dma_write(hsdma, MTK_HSDMA_INT_ENABLE, 0);
 	mtk_dma_write(hsdma, MTK_HSDMA_GLO, MTK_HSDMA_GLO_DEFAULT);
 
 	return 0;
+
+err_put_pm:
+	pm_runtime_put_sync(hsdma2dev(hsdma));
+
+	return err;
 }
 
 static int mtk_hsdma_hw_deinit(struct mtk_hsdma_device *hsdma)
@@ -868,7 +878,6 @@ static int mtk_hsdma_hw_deinit(struct mtk_hsdma_device *hsdma)
 	clk_disable_unprepare(hsdma->clk);
 
 	pm_runtime_put_sync(hsdma2dev(hsdma));
-	pm_runtime_disable(hsdma2dev(hsdma));
 
 	return 0;
 }
@@ -983,7 +992,9 @@ static int mtk_hsdma_probe(struct platform_device *pdev)
 		goto err_unregister;
 	}
 
-	mtk_hsdma_hw_init(hsdma);
+	err = mtk_hsdma_hw_init(hsdma);
+	if (err)
+		goto err_free;
 
 	err = devm_request_irq(&pdev->dev, hsdma->irq,
 			       mtk_hsdma_irq, 0,
@@ -991,7 +1002,7 @@ static int mtk_hsdma_probe(struct platform_device *pdev)
 	if (err) {
 		dev_err(&pdev->dev,
 			"request_irq failed with err %d\n", err);
-		goto err_free;
+		goto err_deinit;
 	}
 
 	platform_set_drvdata(pdev, hsdma);
@@ -1000,8 +1011,9 @@ static int mtk_hsdma_probe(struct platform_device *pdev)
 
 	return 0;
 
-err_free:
+err_deinit:
 	mtk_hsdma_hw_deinit(hsdma);
+err_free:
 	of_dma_controller_free(pdev->dev.of_node);
 err_unregister:
 	dma_async_device_unregister(dd);
-- 
2.47.1