From: Srinivas Kandagatla <[email protected]> When Linux is master of BAM, it can directly read registers to know number of supported channels, however when its remotely controlled reading these registers would trigger a crash if the BAM is not yet intialized/powered up on the remote side.
This patch adds num-channels binding to specify number of supported dma channels on remotely controlled BAM. Signed-off-by: Srinivas Kandagatla <[email protected]> --- Documentation/devicetree/bindings/dma/qcom_bam_dma.txt | 2 ++ drivers/dma/qcom/bam_dma.c | 13 +++++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt index 9cbf5d9df8fd..aa6822cbb230 100644 --- a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt +++ b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt @@ -15,6 +15,8 @@ Required properties: the secure world. - qcom,controlled-remotely : optional, indicates that the bam is controlled by remote proccessor i.e. execution environment. +- num-channels : optional, indicates supported number of DMA channels in a + remotely controlled bam. Example: diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c index 78e488e8f96d..523bd178047a 100644 --- a/drivers/dma/qcom/bam_dma.c +++ b/drivers/dma/qcom/bam_dma.c @@ -1083,8 +1083,10 @@ static int bam_init(struct bam_device *bdev) if (bdev->ee >= val) return -EINVAL; - val = readl_relaxed(bam_addr(bdev, 0, BAM_NUM_PIPES)); - bdev->num_channels = val & BAM_NUM_PIPES_MASK; + if (!bdev->num_channels) { + val = readl_relaxed(bam_addr(bdev, 0, BAM_NUM_PIPES)); + bdev->num_channels = val & BAM_NUM_PIPES_MASK; + } if (bdev->controlled_remotely) return 0; @@ -1179,6 +1181,13 @@ static int bam_dma_probe(struct platform_device *pdev) bdev->controlled_remotely = of_property_read_bool(pdev->dev.of_node, "qcom,controlled-remotely"); + if (bdev->controlled_remotely) { + ret = of_property_read_u32(pdev->dev.of_node, "num-channels", + &bdev->num_channels); + if (ret) + dev_err(bdev->dev, "num-channels unspecified in dt\n"); + } + bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk"); if (IS_ERR(bdev->bamclk)) { bdev->bamclk = NULL; -- 2.15.1
