[U-Boot] [PATCH] S3C6400/SMDK6400: fix stack_setup in start.S

["Seunghyeon Rhee (이승현)"]

Dear Minkyu Kang,

2009/11/2 Minkyu Kang <promsoft at gmail.com>:
> Dear Seunghyeon Rhee
>
> 2009/10/31 "Seunghyeon Rhee (이승현)" <seunghyeon at lpmtec.com>:
>> stack_setup is modified to initialize the stack on the correct address in
>> DRAM accroding to the typical memory configuration described in
>> README and the related CONFIG_* macro definitions. This makes macro
>> CONFIG_MEMORY_UPPER_CODE no longer necessry. This was introduced
>> and used only by this board for some unclear reason. The definition of
>> this macro is removed because it's not referenced elsewhere.
>>
>> Signed-off-by: Seunghyeon Rhee <seunghyeon at lpmtec.com>
>> ---
>>  cpu/arm1176/start.S        |    7 +------
>>  include/configs/smdk6400.h |    2 --
>>  2 files changed, 1 insertions(+), 8 deletions(-)
>>
>> diff --git a/cpu/arm1176/start.S b/cpu/arm1176/start.S
>> index cb891df..1ecb3b9 100644
>> --- a/cpu/arm1176/start.S
>> +++ b/cpu/arm1176/start.S
>> @@ -241,16 +241,11 @@ mmu_enable:
>>  skip_hw_init:
>>     /* Set up the stack                            */
>>  stack_setup:
>> -#ifdef CONFIG_MEMORY_UPPER_CODE
>> -    ldr    sp, =(CONFIG_SYS_UBOOT_BASE + CONFIG_SYS_UBOOT_SIZE - 0xc)
>> -#else
>> -    ldr    r0, _TEXT_BASE        /* upper 128 KiB: relocated uboot   */
>> +    ldr    r0, =CONFIG_SYS_UBOOT_BASE    /* base of copy in
DRAM        */
>
> this change is unnecessary, TEXT_BASE and CONFIG_SYS_UBOOT_BASE must
be same.

That's true for the body of U-Boot but not for SPL, where TEXT_BASE is
defined to be '0'.
Please refer to board/samsung/smdk6400/config.mk. On the other hand,
CONFIG_SYS_UBOOT_BASE is always dependent on DRAM's base.
In SPL, the base of the code should be '0' (the steppingstone memory)
and then the stack
is located below '0' - not a valid area. If SPL itself requires no
stack, it should be no
problem. But start.S calls nand_boot function right after the stack is
badly set up in the air.

My test results are like the following:
with CONFIG_MEMORY_UPPER_CODE defined : OK
with CONFIG_MEMORY_UPPER_CODE undefined :
 - SPL bypassed (U-Boot downloaded to DRAM directly by USB monitor
program) : OK
 - through SPL : Not OK (seems to fail for SPL downloading the code to DRAM)

I think CONFIG_MEMORY_UPPER_CODE was tested for the case it's defined
but not
enough for the case it's not defined. Would you check it again?

> btw, is there need CONFIG_SYS_UBOOT_BASE define?
>

If you are not sure, why did you use CONFIG_SYS_UBOOT_BASE for the
case CONFIG_MEMORY_UPPER_CODE is defined while you use TEXT_BASE
otherwise? I think the unnecessary macro definition here is not
CONFIG_..._BASE but
CONFIG_..._CODE. TEXT_BASE and CONFIG_..._BASE have their own meanings and
so both are necessary.

Best regards,
Seunghyeon


>>     sub    r0, r0, #CONFIG_SYS_MALLOC_LEN    /* malloc
>> area                      */
>>     sub    r0, r0, #CONFIG_SYS_GBL_DATA_SIZE /*
>> bdinfo                        */
>>     sub    sp, r0, #12        /* leave 3 words for abort-stack    */
>>
>> -#endif
>> -
>>  clear_bss:
>>     ldr    r0, _bss_start        /* find start of bss segment        */
>>     ldr    r1, _bss_end        /* stop here                        */
>> diff --git a/include/configs/smdk6400.h b/include/configs/smdk6400.h
>> index f6e1221..f644cd2 100644
>> --- a/include/configs/smdk6400.h
>> +++ b/include/configs/smdk6400.h
>> @@ -49,8 +49,6 @@
>>  #define CONFIG_ENABLE_MMU
>>  #endif
>>
>> -#define CONFIG_MEMORY_UPPER_CODE
>> -
>>  #define CONFIG_SETUP_MEMORY_TAGS
>>  #define CONFIG_CMDLINE_TAG
>>  #define CONFIG_INITRD_TAG
>> --
>> 1.6.2.5
>>
>>
>> --
>> Seunghyeon Rhee, Ph.D. / Director
>> LPM Technology Inc.
>> T +82-70-8255-6007  F +82-2-6442-6462
>> M +82-10-2790-0657
>> _______________________________________________
>> U-Boot mailing list
>> U-Boot at lists.denx.de
>> http://lists.denx.de/mailman/listinfo/u-boot
>>
>
> Thanks for patch :)
> Minkyu Kang
> --
> from. prom.
> www.promsoft.net
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot
>


-- 
Seunghyeon Rhee, Ph.D. / Director
LPM Technology Inc.
T +82-70-8255-6007  F +82-2-6442-6462
M +82-10-2790-0657