On Sat, Feb 23, 2013 at 10:16:21PM +0000, Arnd Bergmann wrote:

On Saturday 23 February 2013, Markus Pargmann wrote:

quoted

+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.

Hmm, so #dma-cells is 1

quoted

@@ -996,13 +1020,33 @@ static void imxdma_issue_pending(struct dma_chan *chan)
 	spin_unlock_irqrestore(&imxdma->lock, flags);
 }
 
+bool imxdma_filter_fn(struct dma_chan *chan, void *param)
+{
+	struct imx_dma_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
+	printk("%s\n", __func__);
+
+	if (!data)
+		return false;
+
+	data->dma_request = *(unsigned *) param;
+	data->alloc_ctl_filter = true;
+	chan->private = data;
+
+	return true;
+}

which matches the usage here, but 

quoted

diff --git a/include/linux/platform_data/dma-imx.h b/include/linux/platform_data/dma-imx.h
index f6d30cc..762a7d0 100644
--- a/include/linux/platform_data/dma-imx.h
+++ b/include/linux/platform_data/dma-imx.h

@@ -51,6 +51,9 @@ struct imx_dma_data {
 	int dma_request; /* DMA request line */
 	enum sdma_peripheral_type peripheral_type;
 	int priority;
+
+	/* Did the controller's filter function allocated this object? */
+	bool alloc_ctl_filter;
 };

There are actually two more members in the imx_dma_data structure. Shouldn't those
be encoded in the dma specifier as well?

imx_dma_data is used by imx-dma and imx-sdma, but imx-dma does not use
peripheral_type and priority. When not loaded from devicetree
imx_dma_data is constructed by imx drivers without knowledge about the
dma driver. This patch moves the initialization to the driver, so I
think there is no need to fill all fields. I didn't want to use a new
struct because the imx drivers could still use this old way.

quoted

 static inline int imx_dma_is_ipu(struct dma_chan *chan)

@@ -63,7 +66,8 @@ 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");
+		!strcmp(dev_name(chan->device->dev), "imx27-dma") ||
+		!strcmp(chan->device->dev->driver->name, "imx-dma");
 }

Also, your filter function does not actually check
imx_dma_is_general_purpose() as the old style filter functions
in the slave drivers do, which breaks when you have more than one dma engine
in the system.

Oh yes, in the filter function should be a device driver comparison. But
I would prefer a direct check instead of imx_dma_is_general_purpose because
I think the driver should not define a filter function that initializes data
for another driver (sdma).

Thanks

Markus

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