dma: imx-dma: Add oftree support

Adding devicetree support for imx-dma driver. Use driver name for
function 'imx_dma_is_general_purpose' because the devicename for
devicetree initialized devices is different.

Signed-off-by: Markus Pargmann <[e-mail]>
Reviewed-by: Arnd Bergmann <[e-mail]>
Reviewed-by: Shawn Guo <[e-mail]>
Acked-by: Sascha Hauer <[e-mail]>
Signed-off-by: Vinod Koul <[e-mail]>

Documentation/devicetree/bindings/dma/fsl-imx-dma.txt

···
+* Freescale Direct Memory Access (DMA) Controller for i.MX
+
+This document will only describe differences to the generic DMA Controller and
+DMA request bindings as described in dma/dma.txt .
+
+* DMA controller
+
+Required properties:
+- compatible : Should be "fsl,<chip>-dma". chip can be imx1, imx21 or imx27
+- reg : Should contain DMA registers location and length
+- interrupts : First item should be DMA interrupt, second one is optional and
+    should contain DMA Error interrupt
+- #dma-cells : Has to be 1. imx-dma does not support anything else.
+
+Optional properties:
+- #dma-channels : Number of DMA channels supported. Should be 16.
+- #dma-requests : Number of DMA requests supported.
+
+Example:
+
+	dma: dma@10001000 {
+		compatible = "fsl,imx27-dma";
+		reg = <0x10001000 0x1000>;
+		interrupts = <32 33>;
+		#dma-cells = <1>;
+		#dma-channels = <16>;
+	};
+
+
+* DMA client
+
+Clients have to specify the DMA requests with phandles in a list.
+
+Required properties:
+- dmas: List of one or more DMA request specifiers. One DMA request specifier
+    consists of a phandle to the DMA controller followed by the integer
+    specifiying the request line.
+- dma-names: List of string identifiers for the DMA requests. For the correct
+    names, have a look at the specific client driver.
+
+Example:
+
+	sdhci1: sdhci@10013000 {
+		...
+		dmas = <&dma 7>;
+		dma-names = "rx-tx";
+		...
+	};

drivers/dma/imx-dma.c

···
 #include <linux/clk.h>
 #include <linux/dmaengine.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
 
 #include <asm/irq.h>
 #include <linux/platform_data/dma-imx.h>
···
 	enum imx_dma_type		devtype;
 };
 
+struct imxdma_filter_data {
+	struct imxdma_engine	*imxdma;
+	int			 request;
+};
+
 static struct platform_device_id imx_dma_devtype[] = {
 	{
 		.name = "imx1-dma",
···
 	}
 };
 MODULE_DEVICE_TABLE(platform, imx_dma_devtype);
+
+static const struct of_device_id imx_dma_of_dev_id[] = {
+	{
+		.compatible = "fsl,imx1-dma",
+		.data = &imx_dma_devtype[IMX1_DMA],
+	}, {
+		.compatible = "fsl,imx21-dma",
+		.data = &imx_dma_devtype[IMX21_DMA],
+	}, {
+		.compatible = "fsl,imx27-dma",
+		.data = &imx_dma_devtype[IMX27_DMA],
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, imx_dma_of_dev_id);
 
 static inline int is_imx1_dma(struct imxdma_engine *imxdma)
 {
···
 	spin_unlock_irqrestore(&imxdma->lock, flags);
 }
 
+static bool imxdma_filter_fn(struct dma_chan *chan, void *param)
+{
+	struct imxdma_filter_data *fdata = param;
+	struct imxdma_channel *imxdma_chan = to_imxdma_chan(chan);
+
+	if (chan->device->dev != fdata->imxdma->dev)
+		return false;
+
+	imxdma_chan->dma_request = fdata->request;
+	chan->private = NULL;
+
+	return true;
+}
+
+static struct dma_chan *imxdma_xlate(struct of_phandle_args *dma_spec,
+						struct of_dma *ofdma)
+{
+	int count = dma_spec->args_count;
+	struct imxdma_engine *imxdma = ofdma->of_dma_data;
+	struct imxdma_filter_data fdata = {
+		.imxdma = imxdma,
+	};
+
+	if (count != 1)
+		return NULL;
+
+	fdata.request = dma_spec->args[0];
+
+	return dma_request_channel(imxdma->dma_device.cap_mask,
+					imxdma_filter_fn, &fdata);
+}
+
 static int __init imxdma_probe(struct platform_device *pdev)
 	{
 	struct imxdma_engine *imxdma;
 	struct resource *res;
+	const struct of_device_id *of_id;
 	int ret, i;
 	int irq, irq_err;
+
+	of_id = of_match_device(imx_dma_of_dev_id, &pdev->dev);
+	if (of_id)
+		pdev->id_entry = of_id->data;
 
 	imxdma = devm_kzalloc(&pdev->dev, sizeof(*imxdma), GFP_KERNEL);
 	if (!imxdma)
···
 		goto err;
 	}
 
+	if (pdev->dev.of_node) {
+		ret = of_dma_controller_register(pdev->dev.of_node,
+				imxdma_xlate, imxdma);
+		if (ret) {
+			dev_err(&pdev->dev, "unable to register of_dma_controller\n");
+			goto err_of_dma_controller;
+		}
+	}
+
 	return 0;
 
+err_of_dma_controller:
+	dma_async_device_unregister(&imxdma->dma_device);
 err:
 	clk_disable_unprepare(imxdma->dma_ipg);
 	clk_disable_unprepare(imxdma->dma_ahb);
···
 
         dma_async_device_unregister(&imxdma->dma_device);
 
+	if (pdev->dev.of_node)
+		of_dma_controller_free(pdev->dev.of_node);
+
 	clk_disable_unprepare(imxdma->dma_ipg);
 	clk_disable_unprepare(imxdma->dma_ahb);
 
···
 static struct platform_driver imxdma_driver = {
 	.driver		= {
 		.name	= "imx-dma",
+		.of_match_table = imx_dma_of_dev_id,
 	},
 	.id_table	= imx_dma_devtype,
 	.remove		= imxdma_remove,

include/linux/platform_data/dma-imx.h

···
 
 static inline int imx_dma_is_general_purpose(struct dma_chan *chan)
 {
-	return strstr(dev_name(chan->device->dev), "sdma") ||
-		!strcmp(dev_name(chan->device->dev), "imx1-dma") ||
-		!strcmp(dev_name(chan->device->dev), "imx21-dma") ||
-		!strcmp(dev_name(chan->device->dev), "imx27-dma");
+	return !strcmp(chan->device->dev->driver->name, "imx-sdma") ||
+		!strcmp(chan->device->dev->driver->name, "imx-dma");
 }
 
 #endif