Hi Vinod, Am 02.12.24 um 17:52 schrieb Vinod Koul:
On 25-10-24, 12:36, Stefan Wahren wrote:bcm2835-dma provides the service to others, so it should suspend late and resume early. Signed-off-by: Stefan Wahren <wahrenst@xxxxxxx> --- drivers/dma/bcm2835-dma.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c index e1b92b4d7b05..647dda9f3376 100644 --- a/drivers/dma/bcm2835-dma.c +++ b/drivers/dma/bcm2835-dma.c @@ -875,6 +875,35 @@ 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; + + if (readl(chan_base + BCM2835_DMA_ADDR)) { + dev_warn(dev, "Suspend is prevented by chan %d\n", + c->ch); + return -EBUSY; + }Can you help understand how this helps by logging... we are not adding anything except checking this and resume is NOP as well!
My intention of this patch is just to make sure, that no DMA transfer is in progress during late_suspend. So i followed the implementation of fsldma.c Additionally i added this warning mostly to know if this ever occurs. But i wasn't able to trigger. Should i drop the warning and make resume callback = NULL? Best regards
