dmaengine: at_xdmac: do not resume channels paused by consumers
authorClaudiu Beznea <claudiu.beznea@microchip.com>
Tue, 14 Feb 2023 15:18:23 +0000 (17:18 +0200)
committerVinod Koul <vkoul@kernel.org>
Wed, 12 Apr 2023 17:48:44 +0000 (23:18 +0530)
commit44fe8440bda545b5d167329df88c47609a645168
tree4a8250f67e4e36a1cf113c2cd950455b0c489a04
parente53957e1ec5196671e49a48f90a5c9555153189a
dmaengine: at_xdmac: do not resume channels paused by consumers

In case there are DMA channels not paused by consumers in suspend
process (valid on AT91 SoCs for serial driver when no_console_suspend) the
driver pauses them (using at_xdmac_device_pause() which is also the same
function called by dmaengine_pause()) and then in the resume process the
driver resumes them calling at_xdmac_device_resume() which is the same
function called by dmaengine_resume()). This is good for DMA channels
not paused by consumers but for drivers that calls
dmaengine_pause()/dmaegine_resume() on suspend/resume path this may lead to
DMA channel being enabled before the IP is enabled. For IPs that needs
strict ordering with regards to DMA channel enablement this will lead to
wrong behavior. To fix this add a new set of functions
at_xdmac_device_pause_internal()/at_xdmac_device_resume_internal() to be
called only on suspend/resume.

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/20230214151827.1050280-4-claudiu.beznea@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
drivers/dma/at_xdmac.c