Re: [PATCH] ACPI: add support for CSRT table

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Wed, Jan 16, 2013 at 12:35:56AM +0100, Rafael J. Wysocki wrote:
> On Monday, January 14, 2013 11:51:51 AM Mika Westerberg wrote:
> > Core System Resources Table (CSRT) is a proprietary ACPI table that
> > contains resources for certain devices that are not found in the DSDT
> > table. Typically a shared DMA controller might be found here.
> > 
> > This patch adds support for this table. We go through all entries in the
> > table and make platform devices of them. The resources from the table are
> > passed with the platform device.
> > 
> > There is one special resource in the table and it is the DMA request line
> > base and number of request lines. This information might be needed by the
> > DMA controller driver as it needs to map the ACPI DMA request line number
> > to the actual request line understood by the hardware. This range is passed
> > as IORESOURCE_DMA resource.
> 
> I have a question: Who's going to bind to those platform devices created
> by the code in this patch and how exactly this is going to happen?

Typically it is the DMA driver (but not limited to that). It is supposed to
work so that either the driver name (in the platform driver struct) matches
the device name in the CSRT or like with the dw_dmac case we do something
like:

/* The platform device created is "INTL9C60.0.auto" */

static const struct platform_device_id dw_dma_ids[] = {
        { "INTL9C60", 0 },
	{ }
}

static struct platform_driver dw_driver = {
	...
	.id_table = dw_dma_ids,
};