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[v3,4/5] dmaengine: qcom: bam_dma: do not write to global regs in remote mode

Message ID 20180215122511.13517-5-srinivas.kandagatla@linaro.org
State Accepted
Commit 54eb5e26cbb72ba77588098385bf5f492b8323ae
Headers show
Series [v3,1/5] dmaengine: qcom: bam_dma: make bam clk optional | expand

Commit Message

Srinivas Kandagatla Feb. 15, 2018, 12:25 p.m. UTC 
From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>


BAM_DESC_CNT_TRSHLD register is global register, which can only be written
when BAM is in master mode, So check the mode of operation before writing
it.

Without this check SOC's xPU would catch such access and crash the system.
First noticed on DB820c while testing SLIMBus BAM.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

---
 drivers/dma/qcom/bam_dma.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

-- 
2.15.1
diff mbox series

Patch

diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 139e9f5e47a9..6919f501b9f3 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -935,12 +935,15 @@  static void bam_apply_new_config(struct bam_chan *bchan,
 	struct bam_device *bdev = bchan->bdev;
 	u32 maxburst;
 
-	if (dir == DMA_DEV_TO_MEM)
-		maxburst = bchan->slave.src_maxburst;
-	else
-		maxburst = bchan->slave.dst_maxburst;
+	if (!bdev->controlled_remotely) {
+		if (dir == DMA_DEV_TO_MEM)
+			maxburst = bchan->slave.src_maxburst;
+		else
+			maxburst = bchan->slave.dst_maxburst;
 
-	writel_relaxed(maxburst, bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
+		writel_relaxed(maxburst,
+			       bam_addr(bdev, 0, BAM_DESC_CNT_TRSHLD));
+	}
 
 	bchan->reconfigure = 0;
 }