From: Amelie Delaunay amelie.delaunay@foss.st.com
[ Upstream commit 140fd5e74a1cc7413df88c735fff5ec64d33c1d3 ]
When disabling dma channel, a TCF flag is set and as TCIE is enabled, an interrupt is raised. On a busy system, the interrupt may have latency and the user can ask for dmaengine_resume while stm32-dma driver has not yet managed the complete pause (backup of registers to restore state in resume). To avoid such a case, instead of waiting the interrupt to backup the registers, do it just after disabling the channel and discard Transfer Complete interrupt in case the channel is paused.
Fixes: 099a9a94be0e ("dmaengine: stm32-dma: add device_pause/device_resume support") Signed-off-by: Amelie Delaunay amelie.delaunay@foss.st.com Link: https://lore.kernel.org/r/20221024083611.132588-1-amelie.delaunay@foss.st.co... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma/stm32-dma.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index adb25a11c70f..5aeaaac846df 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -663,6 +663,8 @@ static void stm32_dma_handle_chan_paused(struct stm32_dma_chan *chan)
chan->chan_reg.dma_sndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
+ chan->status = DMA_PAUSED; + dev_dbg(chan2dev(chan), "vchan %pK: paused\n", &chan->vchan); }
@@ -775,9 +777,7 @@ static irqreturn_t stm32_dma_chan_irq(int irq, void *devid) if (status & STM32_DMA_TCI) { stm32_dma_irq_clear(chan, STM32_DMA_TCI); if (scr & STM32_DMA_SCR_TCIE) { - if (chan->status == DMA_PAUSED && !(scr & STM32_DMA_SCR_EN)) - stm32_dma_handle_chan_paused(chan); - else + if (chan->status != DMA_PAUSED) stm32_dma_handle_chan_done(chan, scr); } status &= ~STM32_DMA_TCI; @@ -824,13 +824,11 @@ static int stm32_dma_pause(struct dma_chan *c) return -EPERM;
spin_lock_irqsave(&chan->vchan.lock, flags); + ret = stm32_dma_disable_chan(chan); - /* - * A transfer complete flag is set to indicate the end of transfer due to the stream - * interruption, so wait for interrupt - */ if (!ret) - chan->status = DMA_PAUSED; + stm32_dma_handle_chan_paused(chan); + spin_unlock_irqrestore(&chan->vchan.lock, flags);
return ret;