Re: [PATCH 21/32] mmc: bcm2835-sdhost: Add new driver for the internal SD controller.

From: Eric Anholt
Date: Thu Jun 02 2016 - 14:12:47 EST

Arnd Bergmann <arnd@xxxxxxxx> writes:

> On Wednesday, June 1, 2016 11:43:30 PM CEST Gerd Hoffmann wrote:
>> + /* Parse OF address directly to get the physical address for
>> + * DMA to our registers.
>> + */
>> + host->phys_addr = be32_to_cpup(of_get_address(pdev->dev.of_node, 0,
>> + NULL, NULL));
> This looks broken on 64-bit systems when #address-cells=<2>, or if there
> is an intermediate bus with a non-empty ranges property.
> What's wrong with platform_get_resource(pdev, IORESOURCE_MEM, 0)?

I'll get to the rest of the review later, but this is a weird pattern
that we have in several bcm2835-related drivers.

We need the address as seen by the DMA controller, not the address from
the ARM's perspective (which is offset by the dma-ranges DT property).
This is the way that people have figured out to get that address.

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