[U-Boot] [PATCH v2 3/4] ARM: use r9 for gd

Jeroen Hofstee
2013-08-19T17:32:02Z

Hello Simon,

On 08/19/2013 05:08 AM, Simon Glass wrote:
> On Sat, Aug 17, 2013 at 3:40 AM, Jeroen Hofstee <jeroen@myspectrum.nl> wrote:
>>
>> This patch assumes only crt0.S sets the register used for
>> gd in asm. I just noticed cpu/armv7/lowlevel_init.S does set gd
>> manually, so all users of the common board.c are likely
>> bricked with the patch as is. Looking into it....
> I may misunderstood what you are saying here,

Likely, this is not about how to set reserve gd, but why gd
is setup twice. The answer is because some more cleanup
is needed (which deserves its own patch).

> but I believe that the
> code in common/board_f.c which creates a global_data on the stack can
> be removed for ARM now that Albert has tidied all this up with the
> crt0.S changes, etc. So in common/board_f.c something like:
>
> void board_init_f(ulong boot_flags)
> {
> /* These two archs set up the global_data before board_init_f() */
> #if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
> gd_t data;
>
> gd = &data;
> #endif
>
> gd->flags = boot_flags;
>

This won't work in general for ARM as board_init_f
returns in the ARM specific board (and will be rather
ugly for the clang case).

Regards,
Jeroen