From: Claudiu Beznea claudiu.beznea@microchip.com
[ Upstream commit 7c5eb63d16b01c202aaa95f374ae15a807745a73 ]
In case the system suspends to a deep sleep state where power to DMA controller is cut-off we need to restore the content of GRWS register. This is a write only register and writing bit X tells the controller to suspend read and write requests for channel X. Thus set GRWS before restoring the content of GE (Global Enable) regiter.
Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver") Signed-off-by: Claudiu Beznea claudiu.beznea@microchip.com Link: https://lore.kernel.org/r/20230214151827.1050280-5-claudiu.beznea@microchip.... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma/at_xdmac.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index fa1e2e0da02f5..34c004a4b23cb 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -2211,6 +2211,15 @@ static int __maybe_unused atmel_xdmac_resume(struct device *dev) return ret; at_xdmac_device_resume_internal(atchan); } + + /* + * We may resume from a deep sleep state where power + * to DMA controller is cut-off. Thus, restore the + * suspend state of channels set though dmaengine API. + */ + else if (at_xdmac_chan_is_paused(atchan)) + at_xdmac_device_pause_set(atxdmac, atchan); + at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, atchan->save_cnda); at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, atchan->save_cndc); at_xdmac_chan_write(atchan, AT_XDMAC_CIE, atchan->save_cim);