Re: [PATCH v2 1/2] dmaengine: dw-edma: Fix unmasking STOP and ABORT interrupts for HDMA

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On 8/2/2024 5:12 AM, Serge Semin wrote:
On Tue, Jul 23, 2024 at 06:49:31PM +0530, Mrinmay Sarkar wrote:
The current logic is enabling both STOP_INT_MASK and ABORT_INT_MASK
bit. This is apparently masking those particular interrupts rather than
unmasking the same. If the interrupts are masked, they would never get
triggered.

So fix the issue by unmasking the STOP and ABORT interrupts properly.

Fixes: e74c39573d35 ("dmaengine: dw-edma: Add support for native HDMA")
cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mrinmay Sarkar <quic_msarkar@xxxxxxxxxxx>
---
  drivers/dma/dw-edma/dw-hdma-v0-core.c | 9 +++++----
  1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
index 10e8f07..fa89b3a 100644
--- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
+++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
@@ -247,10 +247,11 @@ static void dw_hdma_v0_core_start(struct dw_edma_chunk *chunk, bool first)
  	if (first) {
  		/* Enable engine */
  		SET_CH_32(dw, chan->dir, chan->id, ch_en, BIT(0));
-		/* Interrupt enable&unmask - done, abort */
-		tmp = GET_CH_32(dw, chan->dir, chan->id, int_setup) |
-		      HDMA_V0_STOP_INT_MASK | HDMA_V0_ABORT_INT_MASK |
-		      HDMA_V0_LOCAL_STOP_INT_EN | HDMA_V0_LOCAL_ABORT_INT_EN;
Just curious, if all the interrupts were actually masked, how has this
been even working?.. In other words if it affected both local and
remote interrupts, then the HDMA driver has never actually worked,
right?

Agreed, it should not work as interrupts were masked.

But as we are enabling LIE/RIE bits (LWIE/RWIE) that eventually enabling watermark
interrupt in HDMA case and somehow on device I could see interrupt was
generating with watermark and stop bit set and it was working.
Since we were not clearing watermark interrupt, it was also causing storm of interrupt.

+		/* Interrupt unmask - STOP, ABORT */
+		tmp = GET_CH_32(dw, chan->dir, chan->id, int_setup) &
+		      ~HDMA_V0_STOP_INT_MASK & ~HDMA_V0_ABORT_INT_MASK;
Please convert this to:
+		/* Interrupt unmask - stop, abort */
+		tmp = GET_CH_32(dw, chan->dir, chan->id, int_setup);
+		tmp &= ~(HDMA_V0_STOP_INT_MASK | HDMA_V0_ABORT_INT_MASK);

-Serge(y)

Sure. Will do

Thanks,
Mrinmay

+		/* Interrupt enable - STOP, ABORT */
+		tmp |= HDMA_V0_LOCAL_STOP_INT_EN | HDMA_V0_LOCAL_ABORT_INT_EN;
  		if (!(dw->chip->flags & DW_EDMA_CHIP_LOCAL))
  			tmp |= HDMA_V0_REMOTE_STOP_INT_EN | HDMA_V0_REMOTE_ABORT_INT_EN;
  		SET_CH_32(dw, chan->dir, chan->id, int_setup, tmp);
--
2.7.4





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