[PATCH v2 4/5] dmaengine: qcom: bam_dma: do not write to global regs in remote mode
From: <hidden>
Date: 2018-02-14 14:47:26
Also in:
dmaengine, linux-arm-msm, lkml
Subsystem:
arm/qualcomm mailing list, dma generic offload engine subsystem, the rest · Maintainers:
Vinod Koul, Linus Torvalds
From: Srinivas Kandagatla <redacted> 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 <redacted> --- drivers/dma/qcom/bam_dma.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 146b5d03256f..88ec515ad125 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; }
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2.15.1