dmaengine: qcom: bam_dma: add controlled-remotely dt property

Some of the peripherals has bam which is controlled by remote
processor, thus the bam dma driver must avoid register writes
which initialise bam hw block. Those registers are protected
from xPU block and any writes to them will lead to secure
violation and system reboot.

Adding the contolled_remotely flag in bam driver to avoid
not permitted register writes in bam_init function.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
Tested-by: Pramod Gurav <gpramod@codeaurora.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 789d5f836bf789476923752e48d1fcb5c982e0a8..d0f878a78fae5235289b5b4eb64f0ed19f6da4f3 100644 (file)
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -387,6 +387,7 @@ struct bam_device {
 
        /* execution environment ID, from DT */
        u32 ee;
+       bool controlled_remotely;
 
        const struct reg_offset_data *layout;
 
@@ -1042,6 +1043,9 @@ static int bam_init(struct bam_device *bdev)
        val = readl_relaxed(bam_addr(bdev, 0, BAM_NUM_PIPES));
        bdev->num_channels = val & BAM_NUM_PIPES_MASK;
 
+       if (bdev->controlled_remotely)
+               return 0;
+
        /* s/w reset bam */
        /* after reset all pipes are disabled and idle */
        val = readl_relaxed(bam_addr(bdev, 0, BAM_CTRL));
@@ -1129,6 +1133,9 @@ static int bam_dma_probe(struct platform_device *pdev)
                return ret;
        }
 
+       bdev->controlled_remotely = of_property_read_bool(pdev->dev.of_node,
+                                               "qcom,controlled-remotely");
+
        bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
        if (IS_ERR(bdev->bamclk))
                return PTR_ERR(bdev->bamclk);