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

[Vlad Lungu]

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