[U-Boot] [PATCH v2] arm: cm4008, cm41xx: set gd->ram_size in dram_init

Andreas Bießmann andreas.devel at googlemail.com
Fri Jul 6 12:25:00 CEST 2012


Dear Yann Vernier,

On 06.07.2012 11:14, Yann Vernier wrote:
> On Friday 06 July 2012 10:43:40 you wrote:
>>>>> =((CONFIG_SYS_SDRAM_BASE+CONFIG_SYS_SDRAM_SIZE-0x10000)<<(22-16) | \ +
>>>>>      (CONFIG_SYS_SDRAM_BASE>>(16-12) | 0x00e))
>>>>
>>>> ugh ... magic. Will it work for every possible setting?
>>>> How about one setting CONFIG_SYS_SDRAM_BASE != 0x0? I the base address
>>>> related to register content in any way?
>>>
>>> It's not a guarded secret, although it is far from obvious where to find
>>> it. One way is micrel.com - Products - Ethernet ICs / ARM based SOC's -
>>> HW Design Kit. Within that zip file,
>>> KS8695X_EVAL_HW_RV4.0_DP/RegDescription/KS8695X Register Description
>>> v1.1.pdf
>>
>> With this information I understand your equation. I think you should not
>> do it that way. You may solve the current state (all devices have 8
>> column, 4 bank and 32 bit). But one adding (well, if that will ever come
>> ;) another board with different setting will get in trouble here and
>> need to find another solution. Maybe more sophisticated by doing another
>> equation.
>>
>> I think a straight forward solution here would be to add another special
>> define in the board config, write the magic number down there and maybe
>> describe what the number stands for. You can then just use the
>> previously defined value in start.S.
>> You may have a look for at91 lowlevel_init, there it is done that way.
> 
> I shall. In fact, I may already have this problem as I need to verify the 
> timing on the flash memory (I have the demo board, not a cm4xxx), and the 
> reason I work on this is that we may design another board soon.
> 
> I'm a little hesitant about how to fit these changes together, though; for now 
> I have three barely separated patches, but overhauling all those magic numbers 
> changes them all yet again. These three patches are all necessary to make my 
> u-boot work in the first place, while fixing the magic values is a code cleanup 
> change - probably editing arch/arm/include/asm/arch-ks8695/platform.h which 
> currently contains a few meaningless constants like KS8695_SDRAM_START and a 
> consistent misspelling of definitions. 
> 
> Could I save the value decoding and corresponding configuration changes for a 
> fourth patch?

I'm fine with this suggestion.
So the next question is who would pull it in mainline? Since this is arm
related I guess Albert is the one in question.
I think these three patches are all fixes to get a board already in
mainline working. So I think we should try to get these in -rc1.
Albert, can you please comment?

Best regards

Andreas Bießmann


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