[PATCH 4.16 219/272] dmaengine: qcom: bam_dma: get num-channels and num-ees from dt

Greg Kroah-Hartman
2018-05-28T11:33:57Z

From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

[ Upstream commit 48d163b1aa6e7f650c0b7a4f9c61c387a6def868 ]

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@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/dma/qcom/bam_dma.c | 27 ++++++++++++++++++++++-----
1 file changed, 22 insertions(+), 5 deletions(-)

--- 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 *b
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
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))
return PTR_ERR(bdev->bamclk);