| Message ID | 20241204165546.77941-1-wahrenst@gmx.net (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [V7] dmaengine: bcm2835-dma: Prevent suspend if DMA channel is busy | expand |
Am 04.12.24 um 17:55 schrieb Stefan Wahren: > 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@gmx.net> gentle ping ... > --- > 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 >
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), }, };
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@gmx.net> --- 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 -- 2.34.1