Commit 9602a843 authored by Stefan Wahren's avatar Stefan Wahren Committed by Vinod Koul
Browse files

dmaengine: bcm2835-dma: Prevent suspend if DMA channel is busy 



bcm2835-dma provides the service to others, so it should suspend
late and resume early. Suspend should be prevented in case a DMA
channel is still busy.

Signed-off-by: default avatarStefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20241204165546.77941-1-wahrenst@gmx.net


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 68811c92

drivers/dma/bcm2835-dma.c

+22 −0
Original line number Diff line number Diff line
@@ -875,6 +875,27 @@ static struct dma_chan *bcm2835_dma_xlate(struct of_phandle_args *spec, 
	return chan;

}



static int bcm2835_dma_suspend_late(struct device *dev)

{

	struct bcm2835_dmadev *od = dev_get_drvdata(dev);

	struct bcm2835_chan *c, *next;



	list_for_each_entry_safe(c, next, &od->ddev.channels,

				 vc.chan.device_node) {

		void __iomem *chan_base = c->chan_base;



		/* Check if DMA channel is busy */

		if (readl(chan_base + BCM2835_DMA_ADDR))

			return -EBUSY;

	}



	return 0;

}



static const struct dev_pm_ops bcm2835_dma_pm_ops = {

	SET_LATE_SYSTEM_SLEEP_PM_OPS(bcm2835_dma_suspend_late, NULL)

};



static int bcm2835_dma_probe(struct platform_device *pdev)

{

	struct bcm2835_dmadev *od;
@@ -1033,6 +1054,7 @@ static struct platform_driver bcm2835_dma_driver = { 
	.driver = {

		.name = "bcm2835-dma",

		.of_match_table = of_match_ptr(bcm2835_dma_of_match),

		.pm = pm_ptr(&bcm2835_dma_pm_ops),

	},

};