[PATCH 5/5 v2] dmaengine: ste_dma40: Fetch disabled channels from DT

[Lee Jones]

    Some platforms have channels which are not available for normal use.
    This information is currently passed though platform data in internal
    BSP kernels. Once those platforms land, they'll need to configure them
    appropriately, so we may as well add the infrastructure.
    
    Cc: Vinod Koul <vinod.koul at intel.com>
    Cc: Dan Williams <djbw at fb.com>
    Cc: Per Forlin <per.forlin at stericsson.com>
    Cc: Rabin Vincent <rabin at rab.in>
    Signed-off-by: Lee Jones <lee.jones at linaro.org>

diff --git a/Documentation/devicetree/bindings/dma/ste-dma40.txt b/Documentation/devicetree/bindings/dma/ste-dma40.txt
index aa272d8..bea5b73 100644
--- a/Documentation/devicetree/bindings/dma/ste-dma40.txt
+++ b/Documentation/devicetree/bindings/dma/ste-dma40.txt
@@ -11,6 +11,7 @@ Required properties:
 Optional properties:
 - dma-channels: Number of channels supported by hardware - if not present
 		the driver will attempt to obtain the information from H/W
+- disabled-channels: Channels which can not be used
 
 Example:
 
@@ -23,6 +24,7 @@ Example:
 
 		#dma-cells = <2>;
 		memcpy-channels  = <56 57 58 59 60>;
+		disabled-channels  = <12>;
 		dma-channels = <8>;
 	};
 
diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index b14de16..658b53b 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -3464,7 +3464,7 @@ static int __init d40_of_probe(struct platform_device *pdev,
 			       struct device_node *np)
 {
 	struct stedma40_platform_data *pdata;
-	int num_phy = 0, num_memcpy = 0;
+	int num_phy = 0, num_memcpy = 0, num_disabled = 0;
 	const const __be32 *list;
 
 	pdata = devm_kzalloc(&pdev->dev,
@@ -3493,6 +3493,21 @@ static int __init d40_of_probe(struct platform_device *pdev,
 				   dma40_memcpy_channels,
 				   num_memcpy);
 
+	list = of_get_property(np, "disabled-channels", &num_disabled);
+	num_disabled /= sizeof(*list);
+
+	if (num_disabled > STEDMA40_MAX_PHYS || num_disabled < 0) {
+		d40_err(&pdev->dev,
+			"Invalid number of disabled channels specified (%d)\n",
+			num_disabled);
+		return -EINVAL;
+	}
+
+	of_property_read_u32_array(np, "disabled-channels",
+				   pdata->disabled_channels,
+				   num_disabled);
+	pdata->disabled_channels[num_disabled] = -1;
+
 	pdev->dev.platform_data = pdata;
 
 	return 0;