[U-Boot] [PATCH v2] arm: Tegra2: Fix ELDK42 gcc failure with inline asm stack pointer load

[Simon Glass]

On Thu, Feb 23, 2012 at 1:25 PM, Tom Warren <twarren.nvidia at gmail.com> wrote:
> On Fri, Feb 17, 2012 at 9:01 AM, Tom Warren <twarren.nvidia at gmail.com> wrote:
>> The 4.2.2 gcc in the ELDK42 release doesn't like the direct SP
>> load using a constant in tegra2_start. Change it to use a load
>> thru another reg using mov sp, %0 : : "r"(CONST).
>>
>> Tested on my Seaboard T20-A03, U-Boot loads and runs OK. Also
>> compiled all tegra2 builds with both gcc 4.2.2 and 4.4.1 OK.
>>
>> Signed-off-by: Tom Warren <twarren at nvidia.com>

Tested on gcc 4.6, sorry I don't have the compiler that fails.

Acked-by: Simon Glass <sjg at chromium.org>
Tested-by: Simon Glass <sjg at chromium.org>

>> ---
>> V2: Change 4 mov/orr's to single mov sp as per Marek Vasut
>>
>>  arch/arm/cpu/armv7/tegra2/ap20.c |   10 +++++-----
>>  1 files changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/arm/cpu/armv7/tegra2/ap20.c b/arch/arm/cpu/armv7/tegra2/ap20.c
>> index 4c44bb3..f0450f4 100644
>> --- a/arch/arm/cpu/armv7/tegra2/ap20.c
>> +++ b/arch/arm/cpu/armv7/tegra2/ap20.c
>> @@ -298,11 +298,11 @@ void tegra2_start(void)
>>                writel(0xC0, &pmt->pmt_cfg_ctl);
>>
>>                /*
>> -               * If we are ARM7 - give it a different stack. We are about to
>> -               * start up the A9 which will want to use this one.
>> -               */
>> -               asm volatile("ldr       sp, =%c0\n"
>> -                       : : "i"(AVP_EARLY_BOOT_STACK_LIMIT));
>> +                * If we are ARM7 - give it a different stack. We are about to
>> +                * start up the A9 which will want to use this one.
>> +                */
>> +               asm volatile("mov       sp, %0\n"
>> +                       : : "r"(AVP_EARLY_BOOT_STACK_LIMIT));
>>
>>                start_cpu((u32)_start);
>>                halt_avp();
>> --
>> 1.7.7.1
>>
>
> Ack? Nak? Can I get some love here?
>
> Albert/Wolfgang - did anyone try this to ensure that it really fixes
> the 6 Tegra2 failures?
>
> Tom
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