This is a note to let you know that I've just added the patch titled
dmaengine: at_xdmac: restore the content of grws register
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dmaengine-at_xdmac-restore-the-content-of-grws-regis.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8aea70b579cb012b7be3da86bef668398d4a3ddf
Author: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
Date: Tue Feb 14 17:18:24 2023 +0200
dmaengine: at_xdmac: restore the content of grws register
[ 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@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230214151827.1050280-5-claudiu.beznea@xxxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index 4965961f55aa2..66bf570a8bd98 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -2063,6 +2063,15 @@ static int atmel_xdmac_resume(struct device *dev)
if (at_xdmac_chan_is_cyclic(atchan)) {
if (at_xdmac_chan_is_paused(atchan))
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);
