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dmaengine: at_xdmac: restore the content of grws register

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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.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Claudiu Beznea 2023-02-14 17:18:24 +02:00 committed by Vinod Koul
parent 44fe8440bd
commit 7c5eb63d16
1 changed files with 9 additions and 0 deletions
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9
drivers/dma/at_xdmac.c
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@ -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);