[U-Boot] [PATCH] arm: rmobile: bugfix: wrong register saving in lowlevel_init

[Tetsuyuki Kobayashi]

Hi Albert, sorry for late response.

(2012/10/06 1:23), Albert ARIBAUD wrote:
> Hi Tetsuyuki,
>
> On Fri,  5 Oct 2012 13:39:22 +0900, Tetsuyuki Kobayashi
> <koba at kmckk.co.jp> wrote:
>
>> lowlevel_init() of rmobile badly assumed that ip register holds return address.
>> The commit "63ee53a7 armv7 cpu_init_crit: Simplify code" breaks this assumption.
>> This patch removes this bad assumption and simplify code.
>>
>> Signed-off-by: Tetsuyuki Kobayashi <koba at kmckk.co.jp>
>> ---
>> Hello, Albert
>> Hello, Tom
>> Thank you for merging my patches.
>>
>> I checked current u-boot-master and found kzm9g board fails to boot because bug.
>> This bugfix patch solves it.
>> I think 2012.10 release should have this bugfix.
>>
>> Iwamatsu-san, could you double check this patch?
>>
>>
>>   arch/arm/cpu/armv7/rmobile/lowlevel_init.S |   12 +-----------
>>   1 file changed, 1 insertion(+), 11 deletions(-)
>>
>> diff --git a/arch/arm/cpu/armv7/rmobile/lowlevel_init.S b/arch/arm/cpu/armv7/rmobile/lowlevel_init.S
>> index 1bd391e..4fdca06 100644
>> --- a/arch/arm/cpu/armv7/rmobile/lowlevel_init.S
>> +++ b/arch/arm/cpu/armv7/rmobile/lowlevel_init.S
>> @@ -76,17 +76,7 @@ loop0:
>>   	bne  loop0
>>
>>   	ldr sp, MERAM_STACK
>
> Is this load of sp still needed?

Yes.
At this point sp is not yet initialized and s_init() uses
stack area.

>
>> -	str ip, [sp]    /* stash old link register */
>> -	mov ip, lr      /* save link reg across call */
>> -
>> -	bl  s_init
>> -
>> -	ldr ip, [sp]    /* restore save ip */
>> -	mov lr, ip      /* restore link reg */
>> -
>> -	/* back to arch calling code */
>> -	mov pc, lr
>> +	b s_init
>>
>>   	.pool
>>   	.align 4