From: Claudiu Beznea claudiu.beznea@microchip.com
[ Upstream commit 44fe8440bda545b5d167329df88c47609a645168 ]
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.... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma/at_xdmac.c | 48 ++++++++++++++++++++++++++++++++++++------ 1 file changed, 42 insertions(+), 6 deletions(-)
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index 7f7557e4c31d7..cb1374b161291 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -186,6 +186,7 @@ enum atc_status { AT_XDMAC_CHAN_IS_CYCLIC = 0, AT_XDMAC_CHAN_IS_PAUSED, + AT_XDMAC_CHAN_IS_PAUSED_INTERNAL, };
struct at_xdmac_layout { @@ -346,6 +347,11 @@ static inline int at_xdmac_chan_is_paused(struct at_xdmac_chan *atchan) return test_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status); }
+static inline int at_xdmac_chan_is_paused_internal(struct at_xdmac_chan *atchan) +{ + return test_bit(AT_XDMAC_CHAN_IS_PAUSED_INTERNAL, &atchan->status); +} + static inline bool at_xdmac_chan_is_peripheral_xfer(u32 cfg) { return cfg & AT_XDMAC_CC_TYPE_PER_TRAN; @@ -1807,6 +1813,26 @@ static int at_xdmac_device_config(struct dma_chan *chan, return ret; }
+static void at_xdmac_device_pause_set(struct at_xdmac *atxdmac, + struct at_xdmac_chan *atchan) +{ + at_xdmac_write(atxdmac, atxdmac->layout->grws, atchan->mask); + while (at_xdmac_chan_read(atchan, AT_XDMAC_CC) & + (AT_XDMAC_CC_WRIP | AT_XDMAC_CC_RDIP)) + cpu_relax(); +} + +static void at_xdmac_device_pause_internal(struct at_xdmac_chan *atchan) +{ + struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); + unsigned long flags; + + spin_lock_irqsave(&atchan->lock, flags); + set_bit(AT_XDMAC_CHAN_IS_PAUSED_INTERNAL, &atchan->status); + at_xdmac_device_pause_set(atxdmac, atchan); + spin_unlock_irqrestore(&atchan->lock, flags); +} + static int at_xdmac_device_pause(struct dma_chan *chan) { struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); @@ -1819,15 +1845,25 @@ static int at_xdmac_device_pause(struct dma_chan *chan) return 0;
spin_lock_irqsave(&atchan->lock, flags); - at_xdmac_write(atxdmac, atxdmac->layout->grws, atchan->mask); - while (at_xdmac_chan_read(atchan, AT_XDMAC_CC) - & (AT_XDMAC_CC_WRIP | AT_XDMAC_CC_RDIP)) - cpu_relax(); + + at_xdmac_device_pause_set(atxdmac, atchan); + /* Decrement runtime PM ref counter for each active descriptor. */ spin_unlock_irqrestore(&atchan->lock, flags);
return 0; }
+static void at_xdmac_device_resume_internal(struct at_xdmac_chan *atchan) +{ + struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); + unsigned long flags; + + spin_lock_irqsave(&atchan->lock, flags); + at_xdmac_write(atxdmac, atxdmac->layout->grwr, atchan->mask); + clear_bit(AT_XDMAC_CHAN_IS_PAUSED_INTERNAL, &atchan->status); + spin_unlock_irqrestore(&atchan->lock, flags); +} + static int at_xdmac_device_resume(struct dma_chan *chan) { struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan); @@ -1982,7 +2018,7 @@ static int __maybe_unused atmel_xdmac_suspend(struct device *dev) atchan->save_cc = at_xdmac_chan_read(atchan, AT_XDMAC_CC); if (at_xdmac_chan_is_cyclic(atchan)) { if (!at_xdmac_chan_is_paused(atchan)) - at_xdmac_device_pause(chan); + at_xdmac_device_pause_internal(atchan); atchan->save_cim = at_xdmac_chan_read(atchan, AT_XDMAC_CIM); atchan->save_cnda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA); atchan->save_cndc = at_xdmac_chan_read(atchan, AT_XDMAC_CNDC); @@ -2027,7 +2063,7 @@ static int __maybe_unused atmel_xdmac_resume(struct device *dev) at_xdmac_chan_write(atchan, AT_XDMAC_CC, atchan->save_cc); if (at_xdmac_chan_is_cyclic(atchan)) { if (at_xdmac_chan_is_paused(atchan)) - at_xdmac_device_resume(chan); + at_xdmac_device_resume_internal(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);