[U-Boot] [PATCH] mx6: Fix the reading of CPU revision

Fabio Estevam
2013-03-27T13:37:12Z

On Wed, Mar 27, 2013 at 5:57 AM, Dirk Behme <dirk.behme@de.bosch.com> wrote:

> Some additional rethinking: I missed that we have a Linux kernel, too ;)
>
> c) It's the job of the Linux kernel to export the CPU revision to the VPU
> library. In case the Linux kernel completely ignores what we are doing in
> U-Boot and calculates the CPU revision itself (*), e.g. by something like
>
> http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/arch/arm/mach-mx6/mm.c?h=imx_3.0.35_1.1.0&id=207f80453c77bc32e04b5fef863f6fe50a7fd1a8#n60
>
> we can do anything in U-Boot. Independent of the VPU library.

Unfortunately VPU library relies on the bootloader to pass the correct
silicon revision.

Eric's tested passing 0 as get_cpu_rev and showed that VPU simply
cannot work on this case.

> In this case I'd propose to just keep Troy's version of get_cpu_rev() as it
> is [1].

This is proven to not to work with mx6solo and VPU, so we need the fix
I proposed.

Here is what I am planning to do:

1. Send a v2 of this patch with the small correction pointed out by Eric
2. Include a weak function to pass get_cpu_rev in common mx6 code

Then on top of that, one can send a patch that prints the mx6 silicon
strings by differentiating between a mx6dual-lite and mx6solo, if it
is worth.

Regards,

Fabio Estevam