[U-Boot] malta: use unmapped flash base address

The physical base address of the NOR flash is 0x1e000000
on the Malta boards. The hardware also maps the first 4MiB
of the flash into the 0x1fc00000-0x1fffffff range.

Currently, U-Boot uses the mapped address to access the
flash, which does not work in recent qemu versions.

Since commit a427338b222b43197c2776cbc996936df0302f51
(mips_malta: correct reading MIPS revision at 0x1fc00010)
writing to the mapped address space causes a CPU exception.
Due to the exception, U-Boot hangs during boot when it tries
to detect the CFI flash chip.

Use the correct physical address for the MALTA_FLASH_BASE
constant to avoid the problem. The change makes it possible
to start U-Boot on a Malta board emulated with Qemu 1.6.1
and 1.7.0-rc0. It also works on older versions (tested with
1.1.1, 1.2.2, 1.4.2, 1.5.3). The change is not tested on a
real Malta board.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Paul Burton <paul.burton@imgtec.com>
---
 arch/mips/include/asm/malta.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

On 11/11/13 14:05, Gabor Juhos wrote:
> The physical base address of the NOR flash is 0x1e000000
> on the Malta boards. The hardware also maps the first 4MiB
> of the flash into the 0x1fc00000-0x1fffffff range.
>
> Currently, U-Boot uses the mapped address to access the
> flash, which does not work in recent qemu versions.
>
> Since commit a427338b222b43197c2776cbc996936df0302f51
> (mips_malta: correct reading MIPS revision at 0x1fc00010)
> writing to the mapped address space causes a CPU exception.
> Due to the exception, U-Boot hangs during boot when it tries
> to detect the CFI flash chip.
>
> Use the correct physical address for the MALTA_FLASH_BASE
> constant to avoid the problem. The change makes it possible
> to start U-Boot on a Malta board emulated with Qemu 1.6.1
> and 1.7.0-rc0. It also works on older versions (tested with
> 1.1.1, 1.2.2, 1.4.2, 1.5.3). The change is not tested on a
> real Malta board.
>
> Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
> Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
> Cc: Paul Burton <paul.burton@imgtec.com>
> ---
>   arch/mips/include/asm/malta.h |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/mips/include/asm/malta.h b/arch/mips/include/asm/malta.h
> index 9b1100b..bd9043d 100644
> --- a/arch/mips/include/asm/malta.h
> +++ b/arch/mips/include/asm/malta.h
> @@ -44,7 +44,7 @@
>   #define MALTA_RESET_BASE		0x1f000500
>   #define GORESET				0x42
>
> -#define MALTA_FLASH_BASE		0x1fc00000
> +#define MALTA_FLASH_BASE		0x1e000000
>
>   #define MALTA_REVISION			0x1fc00010
>   #define MALTA_REVISION_CORID_SHF	10
>

Hmm, this does run on a real Malta but it takes around a minute to run 
relocate_code... With the 0x1fc00000 base address it's much faster. I'll 
see if I can figure out why...

Paul

2013.11.11. 15:22 keltezéssel, Paul Burton írta:

<...>

>> diff --git a/arch/mips/include/asm/malta.h b/arch/mips/include/asm/malta.h
>> index 9b1100b..bd9043d 100644
>> --- a/arch/mips/include/asm/malta.h
>> +++ b/arch/mips/include/asm/malta.h
>> @@ -44,7 +44,7 @@
>>   #define MALTA_RESET_BASE        0x1f000500
>>   #define GORESET                0x42
>>
>> -#define MALTA_FLASH_BASE        0x1fc00000
>> +#define MALTA_FLASH_BASE        0x1e000000
>>
>>   #define MALTA_REVISION            0x1fc00010
>>   #define MALTA_REVISION_CORID_SHF    10
>>
> 
> Hmm, this does run on a real Malta but it takes around a minute to run
> relocate_code... With the 0x1fc00000 base address it's much faster. I'll see if
> I can figure out why...

Hm, you are right. Although I did not notice that before, but with this patch
U-Boot starts slower also in qemu. It seems that the problem is in the
relocation code. I'm preparing a patch to fix that.

-Gabor