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Re: EDB7312 - Linux booting


On Fri, 2003-02-07 at 04:04, Jonathan Larmour wrote:
> Gary Thomas wrote:
> > Index: hal/arm/arch/current/src/redboot_linux_exec.c
> [snip]
> > -    params->u.mem.start = CYGARC_PHYSICAL_ADDRESS(CYGMEM_REGION_ram);
> >      /* Round up so there's only one bit set in the memory size.
> >       * Don't double it if it's already a power of two, though.
> >       */
> >      params->u.mem.size  = 1<<hal_msbindex(CYGMEM_REGION_ram_SIZE);
> >      if (params->u.mem.size < CYGMEM_REGION_ram_SIZE)
> >  	    params->u.mem.size <<= 1;
> > +    params->u.mem.start = CYGARC_PHYSICAL_ADDRESS(CYGMEM_REGION_ram);
> > +    // Linux doesn't like physical RAM to start on odd boundary 
> > +    params->u.mem.start &= ~(params->u.mem.size-1);
> 
> Excuse my ignorance, but why is this a power of two? Physical memory may 
> not be a power of two certainly.

Ask Mark, he wrote this [I think] :-)

I was just fixing a confusion here with the EDB7xxx in that it's
really muddy when it computes the base address of RAM.

-- 
------------------------------------------------------------
Gary Thomas                 |
MLB Associates              |  Consulting for the
+1 (970) 229-1963           |    Embedded world
http://www.mlbassoc.com/    |
email: <gary@mlbassoc.com>  |
gpg: http://www.chez-thomas.org/gary/gpg_key.asc
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