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Re: broken RM7000 in CVS ...

To: "Kevin D. Kissell" <kevink@mips.com>
Subject: Re: broken RM7000 in CVS ...
From: Jun Sun <jsun@mvista.com>
Date: Fri, 12 Jan 2001 10:58:19 -0800
Cc: linux-mips@oss.sgi.com
References: <3A5E7FFB.79925DF9@mvista.com> <001e01c07c68$96155f80$0deca8c0@Ulysses>
Sender: owner-linux-mips@oss.sgi.com
"Kevin D. Kissell" wrote:
> 
> Yes, arguably the mips_cpu structure could also contain
> a descriptor of the MMU routines to bind, and it probably
> would have if it would have been a simple matter of an
> address/length of a vector to copy.  But heck, it could
> be a function pointer as well, I suppose.
> 

I think that is a good idea.  I suggest we have two more pointers in the
mips_cpu strcuture : one to mips_mmu_ops structure, and the other to
setup_exception_vectors() function.

BTW, I have a question about MIPS32 (or 4KC).  Do all MIPS32 CPUs have the
same PRID?  Or all "incarnations" of 4KC have the same PRID?  I suppose MIPS32
CPUs have a more complete config register where you can probe for all the
options.  For others we can use a table-like structure to fill in the options.

Along this line, it probably makes sense to have another pointer to
mips_cpu_config() function, where for MIPS32 it is the standard MIPS32 config
probing function and for most others it is NULL.

Now the mips_cpu_table looks like :

struct mips_cpu mips_cpu_table[]={
        { PRID_IMP_4KC, mips32_cpu_config},
        { PRID_IMP_RM7K, null, 0xaaa, {...}}
        .....
};

The cpu_probe() routine will now look like:
{
   read prid register
   find mips_cpu_table[i] with matching PRID.
   mips_cpu = &mips_cpu_table[i];
   if (mips_cpu->mips_cpu_config) mips_cpu->mips_cpu_config();
}

To me this is beautiful. Am I dreaming? :-)

Jun

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