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Re: [Qemu-devel] U-Boot patch for qemu -M mips
From: |
Thiemo Seufer |
Subject: |
Re: [Qemu-devel] U-Boot patch for qemu -M mips |
Date: |
Wed, 3 Oct 2007 14:37:06 +0100 |
User-agent: |
Mutt/1.5.16 (2007-06-11) |
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?
Since the mips_r4k machine doesn't correspond to any real hardware we
have a bit of leeway with the "hardware" design.
>>> +}
>>> +
>>> +
>>> +int checkboard (void)
>>> +{
>>> + u32 proc_id;
>>> +
>>> + proc_id = read_32bit_cp0_register(CP0_PRID);
>>> +
>>> + switch (proc_id >> 24) {
>>> + default:
>>> + printf ("Unsupported cpu %d, proc_id=0x%x\n", proc_id >>
>>> 24, proc_id);
>>> + }
>>> +
>>> + return 0;
>>> +}
>>>
>>
>> Huh? What is this code good for?
>>
>>
> Checking for the type of board, I suppose :-) I think all BSPs have it and
> it's called early in the boot process. I could either do only a return 0 or
> actually decode CP0_PRID and print something meaningful, if Qemu sets it to
> something sensible. Or just print a nice banner.
As it is, this code prints a nice "Unsupported CPU" banner no matter what
(and proceeds anyway instead of bailing out).
Latest CVS Qemu supports a number of different CPUs (see the -cpu switch),
the default for 32 bit is a 24Kf, and for 64 bit a R4000.
Thiemo
- [Qemu-devel] U-Boot patch for qemu -M mips, Vlad Lungu, 2007/10/02
- Re: [Qemu-devel] U-Boot patch for qemu -M mips, Thiemo Seufer, 2007/10/02
- Re: [Qemu-devel] U-Boot patch for qemu -M mips, Vlad Lungu, 2007/10/03
- Re: [Qemu-devel] U-Boot patch for qemu -M mips,
Thiemo Seufer <=
- Re: [Qemu-devel] U-Boot patch for qemu -M mips, Vlad Lungu, 2007/10/03
- Re: [Qemu-devel] U-Boot patch for qemu -M mips, Thiemo Seufer, 2007/10/03
- Re: [Qemu-devel] U-Boot patch for qemu -M mips, Vlad Lungu, 2007/10/04
- Re: [Qemu-devel] U-Boot patch for qemu -M mips, Thiemo Seufer, 2007/10/04
- Re: [Qemu-devel] U-Boot patch for qemu -M mips, vlad, 2007/10/04
- Re: [Qemu-devel] U-Boot patch for qemu -M mips TAKE 2, Vlad Lungu, 2007/10/04
- Re: [Qemu-devel] U-Boot patch for qemu -M mips TAKE 2, Wolfgang Denk, 2007/10/04
- Re: [Qemu-devel] U-Boot patch for qemu -M mips TAKE 2, Vlad Lungu, 2007/10/04