ARM: edma: Fix clearing of unused list for DT DMA resources

HWMOD removal for MMC is breaking edma_start as the events are being manually
triggered due to unused channel list not being clear.

The above issue is fixed by reading the "dmas" property from the DT node if it
exists and clearing the bits in the unused channel list if the dma controller
used by any device is EDMA. For this purpose we use the of_* helpers to parse
the arguments in the dmas phandle list.

Also introduced is a minor clean up of a checkpatch error in old code.
Reviewed-by: Sekhar Nori <nsekhar@ti.com>
Reported-by: Balaji T K <balajitk@ti.com>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Nishanth Menon <nm@ti.com>
Cc: Pantel Antoniou <panto@antoniou-consulting.com>
Cc: Jason Kridner <jkridner@beagleboard.org>
Cc: Koen Kooi <koen@dominion.thruhere.net>
Signed-off-by: Joel Fernandes <joelf@ti.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/common/edma.c

@@ -269,6 +269,11 @@ static const struct edmacc_param dummy_paramset = {
 	.ccnt = 1,
 };
 
+static const struct of_device_id edma_of_ids[] = {
+	{ .compatible = "ti,edma3", },
+	{}
+};
+
 /*****************************************************************************/
 
 static void map_dmach_queue(unsigned ctlr, unsigned ch_no,
@@ -560,8 +565,32 @@ static int reserve_contiguous_slots(int ctlr, unsigned int id,
 static int prepare_unused_channel_list(struct device *dev, void *data)
 {
 	struct platform_device *pdev = to_platform_device(dev);
-	int i, ctlr;
+	int i, count, ctlr;
+	struct of_phandle_args  dma_spec;
 
+	if (dev->of_node) {
+		count = of_property_count_strings(dev->of_node, "dma-names");
+		if (count < 0)
+			return 0;
+		for (i = 0; i < count; i++) {
+			if (of_parse_phandle_with_args(dev->of_node, "dmas",
+						       "#dma-cells", i,
+						       &dma_spec))
+				continue;
+
+			if (!of_match_node(edma_of_ids, dma_spec.np)) {
+				of_node_put(dma_spec.np);
+				continue;
+			}
+
+			clear_bit(EDMA_CHAN_SLOT(dma_spec.args[0]),
+				  edma_cc[0]->edma_unused);
+			of_node_put(dma_spec.np);
+		}
+		return 0;
+	}
+
+	/* For non-OF case */
 	for (i = 0; i < pdev->num_resources; i++) {
 		if ((pdev->resource[i].flags & IORESOURCE_DMA) &&
 				(int)pdev->resource[i].start >= 0) {
@@ -1762,11 +1791,6 @@ static int edma_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static const struct of_device_id edma_of_ids[] = {
-	{ .compatible = "ti,edma3", },
-	{}
-};
-
 static struct platform_driver edma_driver = {
 	.driver = {
 		.name	= "edma",