From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
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 initialized or
powered up on the remote side.
This patch allows driver to read num-channels and num-ees from Device Tree
for remotely controlled BAM.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
---
drivers/dma/qcom/bam_dma.c | 27 ++++++++++++++++++++++-----
1 file changed, 22 insertions(+), 5 deletions(-)
diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index b79691fcc82d..139e9f5e47a9 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -393,6 +393,7 @@ struct bam_device {
struct device_dma_parameters dma_parms;
struct bam_chan *channels;
u32 num_channels;
+ u32 num_ees;
/* execution environment ID, from DT */
u32 ee;
@@ -1128,15 +1129,19 @@ static int bam_init(struct bam_device *bdev)
u32 val;
/* read revision and configuration information */
- val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION)) >> NUM_EES_SHIFT;
- val &= NUM_EES_MASK;
+ if (!bdev->num_ees) {
+ val = readl_relaxed(bam_addr(bdev, 0, BAM_REVISION));
+ bdev->num_ees = (val >> NUM_EES_SHIFT) & NUM_EES_MASK;
+ }
/* check that configured EE is within range */
- if (bdev->ee >= val)
+ if (bdev->ee >= bdev->num_ees)
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;
@@ -1232,6 +1237,18 @@ 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");
+
+ ret = of_property_read_u32(pdev->dev.of_node, "qcom,num-ees",
+ &bdev->num_ees);
+ if (ret)
+ dev_err(bdev->dev, "num-ees unspecified in dt\n");
+ }
+
bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
if (IS_ERR(bdev->bamclk)) {
if (!bdev->controlled_remotely)
--
2.15.1
--
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