[PATCH v3 1/7] dmaengine: fsl-edma: unregister channels before vchan cleanup

["Peng Fan (OSS)" <peng.fan@oss.nxp.com>]

From: Peng Fan <peng.fan@nxp.com>

Since commit 4035726a6b72 ("dmaengine: fsl-edma: Use managed API
dmaenginem_async_device_register()"), dma_async_device_unregister() runs
as a devres action after fsl_edma_remove(). However, fsl_edma_remove()
still calls fsl_edma_cleanup_vchan() first, which removes every channel
from dma_dev.channels.  When the devres action later runs,
dma_async_device_unregister() sees an empty channel list and never
unregisters the channel devices. They remain visible in /sys/class/dma.

Keep the vchan cleanup, but register it as a devres action before
dmaenginem_async_device_register(). Devres actions run in reverse
order, so the DMA channels are unregistered first and the vchan list is
cleaned up afterwards. Remove the premature cleanup call from
fsl_edma_remove().

Fixes: 4035726a6b72 ("dmaengine: fsl-edma: Use managed API dmaenginem_async_device_register()")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/dma/fsl-edma-main.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/fsl-edma-main.c b/drivers/dma/fsl-edma-main.c
index 630285c854824..30d548a723462 100644
--- a/drivers/dma/fsl-edma-main.c
+++ b/drivers/dma/fsl-edma-main.c
@@ -31,6 +31,11 @@ static void fsl_edma_synchronize(struct dma_chan *chan)
 	vchan_synchronize(&fsl_chan->vchan);
 }
 
+static void fsl_edma_cleanup_vchan_action(void *data)
+{
+	fsl_edma_cleanup_vchan(data);
+}
+
 static irqreturn_t fsl_edma_tx_handler(int irq, void *dev_id)
 {
 	struct fsl_edma_engine *fsl_edma = dev_id;
@@ -882,6 +887,12 @@ static int fsl_edma_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, fsl_edma);
 
+	ret = devm_add_action_or_reset(&pdev->dev,
+				       fsl_edma_cleanup_vchan_action,
+				       &fsl_edma->dma_dev);
+	if (ret)
+		return ret;
+
 	ret = dmaenginem_async_device_register(&fsl_edma->dma_dev);
 	if (ret)
 		return dev_err_probe(&pdev->dev, ret,
@@ -906,7 +917,6 @@ static void fsl_edma_remove(struct platform_device *pdev)
 	struct fsl_edma_engine *fsl_edma = platform_get_drvdata(pdev);
 
 	fsl_edma_irq_exit(pdev, fsl_edma);
-	fsl_edma_cleanup_vchan(&fsl_edma->dma_dev);
 }
 
 static int fsl_edma_suspend_late(struct device *dev)

-- 
2.34.1