On Tue, Jun 10, 2014 at 09:15:14PM +0200, Arnd Bergmann wrote:

On Tue, May 27, 2014 at 10:35:36AM +0200, Ludovic Desroches wrote:

quoted

+static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
+                                    struct of_dma *of_dma)
+{
+     struct at_xdmac_chan    *atchan;
+     struct dma_chan         *chan;
+     dma_cap_mask_t          mask;
+     struct platform_device  *pdev = of_find_device_by_node(dma_spec->np);

No need to search through all the device nodes, you can look up the
device from of_dma->of_dma_data.

Thanks for the tip.

quoted

+     if (dma_spec->args_count != 2) {
+             dev_err(&pdev->dev, "dma phandler args: bad number of args\n");
+             return NULL;
+     }
+
+     dma_cap_zero(mask);
+     dma_cap_set(DMA_SLAVE, mask);
+     chan = dma_request_channel(mask, NULL, NULL);
+     if (!chan) {
+             dev_err(&pdev->dev, "can't get a dma channel\n");
+             return NULL;
+     }

You must use dma_get_any_slave_channel. dma_request_channel gives you a
channel from a random dma engine that is present in the system, not
necessarily the one you are managing here.

It is planned to use dma_get_any_slave_channel but currently I am doing
tests on a 3.10 kernel that's why I am still using dma_request_channel.

	Arnd
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