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dmaengine: qcom: bam_dma: do not write to global regs in remote mode 

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>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Srinivas Kandagatla 2018-02-15 12:25:10 +00:00 committed by Vinod Koul
parent 48d163b1aa
commit 54eb5e26cb
1 changed files with 8 additions and 5 deletions
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13
drivers/dma/qcom/bam_dma.c
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@ -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;
}