linux-kernel - [PATCH v2] dmaengine: qcom: bam

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Message-Id: <20220629140323.116981-1-caleb.connolly@linaro.org>
Date:   Wed, 29 Jun 2022 15:03:23 +0100
From:   Caleb Connolly <caleb.connolly@...aro.org>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Vinod Koul <vkoul@...nel.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        linux-arm-msm@...r.kernel.org, dmaengine@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Caleb Connolly <caleb.connolly@...aro.org>,
        Stephan Gerhold <stephan@...hold.net>
Subject: [PATCH v2] dmaengine: qcom: bam_dma: fix runtime PM underflow

Commit dbad41e7bb5f ("dmaengine: qcom: bam_dma: check if the runtime pm enabled")
caused unbalanced pm_runtime_get/put() calls when the bam is
controlled remotely. This commit reverts it and just enables pm_runtime
in all cases, the clk_* functions already just nop the clock is NULL.

Also clean up a bit by removing unnecessary bamclk null checks.

Suggested-by: Stephan Gerhold <stephan@...hold.net>
Fixes: dbad41e7bb5f ("dmaengine: qcom: bam_dma: check if the runtime pm enabled")
Signed-off-by: Caleb Connolly <caleb.connolly@...aro.org>
---

Boot tested on a OnePlus 6

v1 can be found here:
https://lore.kernel.org/linux-arm-msm/20220609195043.1544625-1-caleb.connolly@linaro.org/

 drivers/dma/qcom/bam_dma.c | 39 +++++++++++---------------------------
 1 file changed, 11 insertions(+), 28 deletions(-)

diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 87f6ca1541cf..2ff787df513e 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -558,14 +558,6 @@ static int bam_alloc_chan(struct dma_chan *chan)
 	return 0;
 }
 
-static int bam_pm_runtime_get_sync(struct device *dev)
-{
-	if (pm_runtime_enabled(dev))
-		return pm_runtime_get_sync(dev);
-
-	return 0;
-}
-
 /**
  * bam_free_chan - Frees dma resources associated with specific channel
  * @chan: specified channel
@@ -581,7 +573,7 @@ static void bam_free_chan(struct dma_chan *chan)
 	unsigned long flags;
 	int ret;
 
-	ret = bam_pm_runtime_get_sync(bdev->dev);
+	ret = pm_runtime_get_sync(bdev->dev);
 	if (ret < 0)
 		return;
 
@@ -784,7 +776,7 @@ static int bam_pause(struct dma_chan *chan)
 	unsigned long flag;
 	int ret;
 
-	ret = bam_pm_runtime_get_sync(bdev->dev);
+	ret = pm_runtime_get_sync(bdev->dev);
 	if (ret < 0)
 		return ret;
 
@@ -810,7 +802,7 @@ static int bam_resume(struct dma_chan *chan)
 	unsigned long flag;
 	int ret;
 
-	ret = bam_pm_runtime_get_sync(bdev->dev);
+	ret = pm_runtime_get_sync(bdev->dev);
 	if (ret < 0)
 		return ret;
 
@@ -919,7 +911,7 @@ static irqreturn_t bam_dma_irq(int irq, void *data)
 	if (srcs & P_IRQ)
 		tasklet_schedule(&bdev->task);
 
-	ret = bam_pm_runtime_get_sync(bdev->dev);
+	ret = pm_runtime_get_sync(bdev->dev);
 	if (ret < 0)
 		return IRQ_NONE;
 
@@ -1037,7 +1029,7 @@ static void bam_start_dma(struct bam_chan *bchan)
 	if (!vd)
 		return;
 
-	ret = bam_pm_runtime_get_sync(bdev->dev);
+	ret = pm_runtime_get_sync(bdev->dev);
 	if (ret < 0)
 		return;
 
@@ -1374,11 +1366,6 @@ static int bam_dma_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_unregister_dma;
 
-	if (!bdev->bamclk) {
-		pm_runtime_disable(&pdev->dev);
-		return 0;
-	}
-
 	pm_runtime_irq_safe(&pdev->dev);
 	pm_runtime_set_autosuspend_delay(&pdev->dev, BAM_DMA_AUTOSUSPEND_DELAY);
 	pm_runtime_use_autosuspend(&pdev->dev);
@@ -1462,10 +1449,8 @@ static int __maybe_unused bam_dma_suspend(struct device *dev)
 {
 	struct bam_device *bdev = dev_get_drvdata(dev);
 
-	if (bdev->bamclk) {
-		pm_runtime_force_suspend(dev);
-		clk_unprepare(bdev->bamclk);
-	}
+	pm_runtime_force_suspend(dev);
+	clk_unprepare(bdev->bamclk);
 
 	return 0;
 }
@@ -1475,13 +1460,11 @@ static int __maybe_unused bam_dma_resume(struct device *dev)
 	struct bam_device *bdev = dev_get_drvdata(dev);
 	int ret;
 
-	if (bdev->bamclk) {
-		ret = clk_prepare(bdev->bamclk);
-		if (ret)
-			return ret;
+	ret = clk_prepare(bdev->bamclk);
+	if (ret)
+		return ret;
 
-		pm_runtime_force_resume(dev);
-	}
+	pm_runtime_force_resume(dev);
 
 	return 0;
 }
-- 
2.36.1