[PATCHv9] dmaengine: Add support for BCM2835

On 02.01.2014 19:03, Arnd Bergmann wrote:

On Thursday 02 January 2014 18:49:23 Florian Meier wrote:

quoted

Add support for DMA controller of BCM2835 as used in the Raspberry Pi.
Currently it only supports cyclic DMA.

Looks very nice. Just a few details I noticed:

quoted

+#if defined(CONFIG_OF)
+static const struct of_device_id bcm2835_dma_of_match[] = {
+ { .compatible = "brcm,bcm2835-dma", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, bcm2835_dma_of_match);
+#endif

I doubt we are going to see non-DT versions of this driver, so the #ifdef
can just get removed here.

As already explained in previous versions of this patch thread, there is
a non-DT version in a downstream kernel and the more I make this patch
incompatible with non-DT, the harder it gets to upstream the remaining
stuff. I hope this is not something that blocks this driver from getting
accepted.

[...]
This can now be simplified using the dma_get_any_slave_channel() interface
taht Stephen Warren introduced.
[...]
dma_set_mask_and_coherent()

Sigh, the API is developing faster than I can keep track with updating
this patch. I hope some day I will be faster....
When Russell told me about the second one before, it hoped that I can
avoid merging different trees on my own, but it seems that you want me
to do that ;-)

quoted

+ if (pdev->dev.of_node) {
+ /* Device-tree DMA controller registration */
+ rc = of_dma_controller_register(pdev->dev.of_node,
+ bcm2835_dma_xlate, od);
+ if (rc) {
+ dev_err(&pdev->dev, "Failed to register DMA controller\n");
+ goto err_no_dma;
+ }
+ }

If pdev->dev.of_node isn't set, you didn't get here, so the if() can be removed.

Why not? (In the case of non-DT initialization)

Greetings,
Florian