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RE: warm boot detection
- From: Doug Fraser <dfraser at photuris dot com>
- To: Ecos-Discuss <ecos-discuss at sources dot redhat dot com>
- Date: Tue, 1 Jul 2003 07:46:23 -0400
- Subject: RE: [ECOS] warm boot detection
Most of the integrated processors have a number
registers that are initialized differently depending
on the reset source. On the MPC850, there is a
a Reset Status Register in the IMMR that lists the
reset cause. It cannot differentiate between
hard reset and power. However, the PLPRCR has
a number of bits that are initialized by a power on
sequence but not by a hard reset. We use one of these
(FIOPD) to determine if the reset was the result of
a power on event.
Doug Fraser
> -----Original Message-----
> From: Jonathan Larmour [mailto:jifl@eCosCentric.com]
> Sent: Monday, June 23, 2003 12:05 PM
> To: aarichar@cisco.com
> Cc: Ecos-Discuss
> Subject: Re: [ECOS] warm boot detection
>
>
> Aaron Richardson wrote:
> > Is there some way that I can detect if the platform has
> been cold booted or
> > warm booted? It would be nice to avoid initializing
> several things based on
> > this. The SDRAM scrubbing and any memory testing could be skipped.
>
> Normally people simply rely on the HAL startup type (ROM/RAM etc.) to
> indicate whether this instance should do the initialization.
> If you mean a
> non-eCos program may have done the init on the other hand...
>
> > Also any
> > chips that need to be skipped during a warm boot could be(I
> have a 21555 pci
> > bridge that needs to be skipped).
>
> Surely the best thing is to look at some register in the PCI
> BIOS to see
> if it's already been initialized?
>
> Or since this is an application specific customisation, just
> add a bit of
> memory at a common address. Look at how hal_dram_size is
> treated in the
> ARM arch HAL for example. Just write a magic number into that
> address when
> booted for the first time and use that to test if it's
> already been booted
> before.
>
> Jifl
> --
> eCosCentric http://www.eCosCentric.com/ The eCos and
> RedBoot experts
> --[ "You can complain because roses have thorns, or you ]--
> --[ can rejoice because thorns have roses." -Lincoln ]--
> Opinions==mine
>
>
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