Commit 54eb5e26 authored Feb 15, 2018 by Srinivas Kandagatla Committed by Vinod Koul Mar 01, 2018

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>

parent 48d163b1

drivers/dma/qcom/bam_dma.c

+8 −5

Original line number	Diff line number	Diff line
		@@ -935,12 +935,15 @@ static void bam_apply_new_config(struct bam_chan *bchan,
		struct bam_device *bdev = bchan->bdev;
		u32 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;
		}