Re: [Qemu-devel] U-Boot patch for qemu -M mips

[Vlad Lungu <vlad@comsys.ro>]

Thiemo Seufer wrote:
> Vlad Lungu wrote:
>   
>> Thiemo Seufer wrote:
>>     
>>> Vlad Lungu wrote:
>>> [snip]
>>>   
>>>       
>>>>>>  +long int initdram(int board_type)
>>>>>>  +{
>>>>>>  +       /* Sdram is setup by assembler code */
>>>>>>  +       /* If memory could be changed, we should return the true value 
>>>>>> here */
>>>>>>  +       return MEM_SIZE*1024*1024;
>>>>>>             
>>>>>>             
>>>>> Qemu gets the amount of RAM passed via a command line switch, the
>>>>> qemu-mips emulation sets up a Linux kernel like "command line" in
>>>>> memory where u-boot could parse it from.
>>>>>
>>>>>         
>>>>>           
>>>> Does it, or just when you pass -kernel to it? I'll check.
>>>>     
>>>>         
>>> Hm, you are right, it does that only for -kernel. Would it make sense
>>> to change that in Qemu?
>>>   
>>>       
>> IDK.  Maybe I can probe the  RAM size in U-Boot , or if this does not work, 
>>     
>
> mips_r4k implements no probable memory controller, so this won't work.
>   
I say let's stick it into a "DIP-switch", so nobody can overwrite it by 
mistake. And you don't have to parse it.
>> put some info somewhere (RAM, register,
>> emulated DIP-dwitch), like RAM size, endianness of the CPU.
>>     
>
> Endianness is rather pointless. If your U-Boot binary doesn't explode
> immediately you got the right endianness. :-)
>
>   
It doesn't actually explode, it sort of almost hits the exception 
handler and freezes there. I don't have a mipsel gdb at hand
to watch it, but it should be fun.
 
pc=EPC   0xbfc00380
ds 0006

STATUS    0x00400006
CAUSE     0x00000428
CONFIG0 0x80000082
CONFIG1 0x9e190c8b