[U-Boot] AT91 working SD with u-boot

[Albin Tonnerre <albin.tonnerre@free-electrons.com>]

On Thu, 01 Oct 2009 11:28 +0200, Sebastian Heutling wrote :
> Hi Konrad,


> On 10/01/2009 10:33 AM, Konrad Mattheis wrote:
> > Hi Sebastian,

> > yes I'm using an AT91SAM9G20-EK Rev.c with two SD slots.
> > I used slot a but I think you just have to init slot b.

> > in PatchV3 you can read:

> >> at91_mci0_hw_init(int slot, int bus_width)

> >> switch (slot) {
> >> 		case 0:
> >> 			.....
> >> 		case 1:
> > So I think you just have to call at91_mci0_hw_init(1,4) for
> > slot b.

> No - that is not enough. It just enables the clock for MCI and 
> configures the pins. But the MCI itself needs to know which slot to 
> address.

> Suppose you want to use both slots at the same time (and the drivers 
> would support that).
> Then you would call:

> at91_mci0_hw_init(0, 4)
> at91_mci0_hw_init(1, 4)

> In order to access both slots the driver (atmel_mci) needs to select 
> which slot to address. And that is what the SDCSEL field of MCI-SDCR is 
> for (see also Datasheet of the AT91SAM9G20 35.9.4 (probably at page 607)).

But the driver doesn't support for the moment. I might add such support if I
have some time (and if that works - has anybody ever tried doing that with
Linux?). For now the best way to get it working is to select the correct slot
in your board config code.

Cheers,
-- 
Albin Tonnerre, Free Electrons
Kernel, drivers and embedded Linux development,
consulting, training and support.
http://free-electrons.com
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