On 14/10/15 14:17, M'boumba Cedric Madianga wrote:
Hi Daniel,
+
+static int stm32_dma_remove(struct platform_device *pdev)
+{
+ struct stm32_dma_device *dmadev = platform_get_drvdata(pdev);
+
+ of_dma_controller_free(pdev->dev.of_node);
+
+ dma_async_device_unregister(&dmadev->ddev);
+
+ clk_disable_unprepare(dmadev->clk);
What is the purpose of disabling/unpreparing the clock here?
stm32_dma_alloc_chan_resources() and stm32_dma_free_chan_resources() should
pair up and the clock should already be stopped.
stm32_dma_remove() could be called during an on-going transfer during
module unload.
So in that case, it seems that disabling/unpreparing the clock is needed.
Really?
I think we need to be sure any on-going transfers are stopped.
There are multiple reasons for this, not least the risk of executing a
callback that has been freed, but the one related to my point is that a
single clk_disable_unprepare() will remain broken because if you don't
know that the transfers have stopped then you don't know how many
on-going transfers there are.
Daniel.
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