[PATCH v2 2/2] ARM: mxs: Pass the system revision

Fabio Estevam festevam at gmail.com
Sat Jun 1 10:58:18 EDT 2013


Hi Michael,

On Sat, Jun 1, 2013 at 9:19 AM, Michael Heimpold <mhei at heimpold.de> wrote:

> I think it would be difficult to use system_rev for this purpose as some
> boards I know about are using this field to pass a board/PCB revision from
> U-Boot to the kernel.

Can you please provide some real examples?

For mx28 I see no boards passing ATAGS from bootloader to the kernel.

If you look at FSL kernel code the system revision is hardcoded in the
board file.

For mx5/mx6 boards we do pass ATAGS from bootloader to kernel in the
same format it was used here.

For example: on mx53 it will be 0x53112 (where 0x53 means mx53, 1 is
the board revision and 12 means TO1.2)

> After spending a short look through documentation in kernel and U-Boot
> I did not find any hint whether this was the indended usage of this field.
>
> I would rather argue about introducing a new line
> "SoC revision: ..." as this is the revision you want to pass to user-space.
>
> The lines "Revision" and "Serial" should IMHO left
> alone for usage by board vendors.

As I mentioned in the commit log, the only reason we are doing this
here is to allow a mainline kernel to run som mxs applications like
Gstreamer plugins and kobs-ng.

Regards,

Fabio Estevam



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