[PATCH v2 1/6] dmaengine: sun6i: fix physical channel index in interrupt handler

[James Hilliard]

From: Hongling Zeng <zenghongling at kylinos.cn>

The interrupt handler iterates over register banks in the outer loop,
but the physical channel lookup uses only the inner loop index. It
therefore handles every bank as if it belonged to the first channels.

For controllers with eight channels per bank, interrupts from channels
8 and above are routed to channels 0-7. On A733, each bank covers one
channel, so every interrupt is routed to channel 0. This can falsely
complete descriptors for unrelated channels and corrupt their data.

Use the absolute channel index, calculated from the bank number and the
controller's configured number of channels per bank.

Fixes: 555859308723 ("dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller")
Cc: stable at vger.kernel.org
Signed-off-by: Hongling Zeng <zenghongling at kylinos.cn>
Reviewed-by: Frank Li <Frank.Li at nxp.com>
[james: use the configured bank size and describe the A733 case]
Signed-off-by: James Hilliard <james.hilliard1 at gmail.com>
---
 drivers/dma/sun6i-dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index 8752969366ff..9d94a37fcf10 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -603,7 +603,7 @@ static irqreturn_t sun6i_dma_interrupt(int irq, void *dev_id)
 		sun6i_write_irq_stat(sdev, i, status);
 
 		for (j = 0; (j < sdev->cfg->num_channels_per_reg) && status; j++) {
-			pchan = sdev->pchans + j;
+			pchan = sdev->pchans + i * sdev->cfg->num_channels_per_reg + j;
 			vchan = pchan->vchan;
 			if (vchan && (status & vchan->irq_type)) {
 				if (vchan->cyclic) {

-- 
2.53.0