On Sat, Feb 12, 2011 at 11:07:17AM +0100, Arnd Bergmann wrote:

On Saturday 12 February 2011 18:23:58 Shawn Guo wrote:

quoted

Well, we are removing inclusion of mach/dma.h from mmc driver, but
adding it to every mxs based machine code.  This makes mmc driver
clean but machine code becomes not.  For some dma client devices
coming later, the platform data could be saved at all, if they do not
have any.  But with the approach you are suggesting, every single
client device will have to get platform data.

Right, unless there is a way to encode it exlusively in the resources,
which is what I was suggesting at first: If the dma engine driver
knows about all the channels, you only need to pass the channel number.

If you use a flattened device tree, you can avoid the need for
platform data by adding the phandle of the dma engine device to
a property of the mmc driver, along with the channel number inside
of that device. I think that would be the cleanest approach, but
some people still need to be convinced that changing drivers to
use fdt data is the right direction for ARM.

Could we keep the current the approach for now and go to the cleanest
way directly when Grant's dt patches get merged?

Regards,
Shawn