Booting without Uboot on 8548E

M Ptich ptich at
Sat Nov 4 20:28:16 EST 2006

>You should seriously think about porting
>over to arch/powerpc instead.

8548E is E500v2 core. Our Kernel is from Freescale, it is using arch/ppc. I 
am not sure how well (if at all) E500 is supported in the arch/powerpc from 
the FSF ditribution.

>I'm not familiar about which core family the 85xx is. Doesn't it use the
>decrementer ?

Actually E500 could use Decrementer, with its Autoreload feature to get an 
exact time tick. I did not think about it, will investigate.

M Ptich

>From: Benjamin Herrenschmidt <benh at>
>To: M Ptich <ptich at>
>CC: linuxppc-dev at
>Subject: Re: Booting without Uboot on 8548E
>Date: Sat, 04 Nov 2006 20:13:40 +1100
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>On Sat, 2006-11-04 at 08:52 +0000, M Ptich wrote:
> > Documentation mentions that the only dependencies between 2.6 Kernel and
> > bootloader are:
> >
> > 1. 5 input parameters (bd_t pointer, start and end of command line, 
> > and end of ram disk)
> > 2. bd_t pointer and command line must with within 16MB of Kernel
> > 3. Initial TLB1 entry must have IPROT=1
>This is for arch/ppc, which is sort-of deprecated. You should seriously
>think about porting over to arch/powerpc instead.
> > Slowly, we are finding that this list is not complete. For example, 
> > calculation at the start of platform_init (r3 + ...) assumes that Kernel 
> > been initially loaded at 0-base virtual address.
>For which CPU core ? 6xx/7xx/7xxx/G2 cores don't assume such a thing,
>the kernel can be loaded anywhere as long as the virtual and physical
>addresses are the same.
> > And now we are stuck with apparently another dependency: our Kernel 
>fails to
> > advance beyond time calibration because jiffies are not getting 
> > so we are not getting timer interrupts. Is it true that Kernel relies on
> > EPIC timer set in Uboot ? If not - where the timer insterrupts are
> > configured ?
>I'm not familiar about which core family the 85xx is. Doesn't it use the
>decrementer ?

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