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: Stefan Wahren <wahrenst@xxxxxxx>
---
drivers/dma/bcm2835-dma.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
Changes in V7:
- improve patch title and changelog
- add explaining comment and drop warning in suspend
- drop empty resume callback
Changes in V6:
- split out of series because there is no dependency
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index 7ba52dee40a9..20b10c15c696 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -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),
},
};
--
2.34.1
