[PATCH v4] dmaengine: sirf: enable generic dt binding for dma channels

[Barry Song]

From: Barry Song <Baohua.Song at csr.com>

move to support of_dma_request_slave_channel() and dma_request_slave_channel.
we add a xlate() to let dma clients be able to find right dma_chan by generic
"dmas" properties in dts.

Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Lars-Peter Clausen <lars at metafoo.de>
Signed-off-by: Barry Song <Baohua.Song at csr.com>
---
 -v4: clear dt-binding document according to Mark's feedback

 .../devicetree/bindings/dma/sirfsoc-dma.txt        |   43 ++++++++++++++++++++
 arch/arm/boot/dts/atlas6.dtsi                      |    2 +
 arch/arm/boot/dts/prima2.dtsi                      |    2 +
 drivers/dma/sirf-dma.c                             |   23 ++++++++++
 4 files changed, 70 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/sirfsoc-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/sirfsoc-dma.txt b/Documentation/devicetree/bindings/dma/sirfsoc-dma.txt
new file mode 100644
index 0000000..ecbc96a
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/sirfsoc-dma.txt
@@ -0,0 +1,43 @@
+* CSR SiRFSoC DMA controller
+
+See dma.txt first
+
+Required properties:
+- compatible: Should be "sirf,prima2-dmac" or "sirf,marco-dmac"
+- reg: Should contain DMA registers location and length.
+- interrupts: Should contain one interrupt shared by all channel
+- #dma-cells: must be <1>. used to represent the number of integer
+    cells in the dmas property of client device.
+- clocks: clock required
+
+Example:
+
+Controller:
+dmac0: dma-controller at b00b0000 {
+	compatible = "sirf,prima2-dmac";
+	reg = <0xb00b0000 0x10000>;
+	interrupts = <12>;
+	clocks = <&clks 24>;
+	#dma-cells = <1>;
+};
+
+
+Client:
+Fill the specific dma request line in dmas. In the below example, spi0 read
+channel request line is 9 of the 2nd dma controller, while write channel uses
+4 of the 2nd dma controller; spi1 read channel request line is 12 of the 1st
+dma controller, while write channel uses 13 of the 1st dma controller:
+
+spi0: spi at b00d0000 {
+	compatible = "sirf,prima2-spi";
+	dmas = <&dmac1 9>,
+		<&dmac1 4>;
+	dma-names = "rx", "tx";
+};
+
+spi1: spi at b0170000 {
+	compatible = "sirf,prima2-spi";
+	dmas = <&dmac0 12>,
+		<&dmac0 13>;
+	dma-names = "rx", "tx";
+};
diff --git a/arch/arm/boot/dts/atlas6.dtsi b/arch/arm/boot/dts/atlas6.dtsi
index b63cfef..4f41f0a 100644
--- a/arch/arm/boot/dts/atlas6.dtsi
+++ b/arch/arm/boot/dts/atlas6.dtsi
@@ -260,6 +260,7 @@
 				reg = <0xb00b0000 0x10000>;
 				interrupts = <12>;
 				clocks = <&clks 24>;
+				#dma-cells = <1>;
 			};
 
 			dmac1: dma-controller at b0160000 {
@@ -268,6 +269,7 @@
 				reg = <0xb0160000 0x10000>;
 				interrupts = <13>;
 				clocks = <&clks 25>;
+				#dma-cells = <1>;
 			};
 
 			vip at b00C0000 {
diff --git a/arch/arm/boot/dts/prima2.dtsi b/arch/arm/boot/dts/prima2.dtsi
index b292a5c..19e4e22 100644
--- a/arch/arm/boot/dts/prima2.dtsi
+++ b/arch/arm/boot/dts/prima2.dtsi
@@ -277,6 +277,7 @@
 				reg = <0xb00b0000 0x10000>;
 				interrupts = <12>;
 				clocks = <&clks 24>;
+				#dma-cells = <1>;
 			};
 
 			dmac1: dma-controller at b0160000 {
@@ -285,6 +286,7 @@
 				reg = <0xb0160000 0x10000>;
 				interrupts = <13>;
 				clocks = <&clks 25>;
+				#dma-cells = <1>;
 			};
 
 			vip at b00C0000 {
diff --git a/drivers/dma/sirf-dma.c b/drivers/dma/sirf-dma.c
index 6aec3ad..8b74c0d 100644
--- a/drivers/dma/sirf-dma.c
+++ b/drivers/dma/sirf-dma.c
@@ -18,6 +18,7 @@
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/clk.h>
+#include <linux/of_dma.h>
 #include <linux/sirfsoc_dma.h>
 
 #include "dmaengine.h"
@@ -640,6 +641,18 @@ bool sirfsoc_dma_filter_id(struct dma_chan *chan, void *chan_id)
 }
 EXPORT_SYMBOL(sirfsoc_dma_filter_id);
 
+static struct dma_chan *of_dma_sirfsoc_xlate(struct of_phandle_args *dma_spec,
+	struct of_dma *ofdma)
+{
+	struct sirfsoc_dma *sdma = ofdma->of_dma_data;
+	unsigned int request = dma_spec->args[0];
+
+	if (request > SIRFSOC_DMA_CHANNELS)
+		return NULL;
+
+	return dma_get_slave_channel(&sdma->channels[request].chan);
+}
+
 static int sirfsoc_dma_probe(struct platform_device *op)
 {
 	struct device_node *dn = op->dev.of_node;
@@ -744,11 +757,20 @@ static int sirfsoc_dma_probe(struct platform_device *op)
 	if (ret)
 		goto free_irq;
 
+	/* Device-tree DMA controller registration */
+	ret = of_dma_controller_register(dn, of_dma_sirfsoc_xlate, sdma);
+	if (ret) {
+		dev_err(dev, "failed to register DMA controller\n");
+		goto unreg_dma_dev;
+	}
+
 	pm_runtime_enable(&op->dev);
 	dev_info(dev, "initialized SIRFSOC DMAC driver\n");
 
 	return 0;
 
+unreg_dma_dev:
+	dma_async_device_unregister(dma);
 free_irq:
 	free_irq(sdma->irq, sdma);
 irq_dispose:
@@ -761,6 +783,7 @@ static int sirfsoc_dma_remove(struct platform_device *op)
 	struct device *dev = &op->dev;
 	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
 
+	of_dma_controller_free(op->dev.of_node);
 	dma_async_device_unregister(&sdma->dma);
 	free_irq(sdma->irq, sdma);
 	irq_dispose_mapping(sdma->irq);
-- 
1.7.5.4