[coreboot] Flashrom support for EPIA-N(L) - patch for review

Harrison, Jon (SELEX GALILEO, UK) jon.harrison at selexgalileo.com
Fri Jun 19 13:06:51 CEST 2009


Received and understood, then the basic issue is that at this point my
coreboot build is still broken and will not boot, so there are no
tables. (I had not realised the tables were read from RAM rather than
the ROM image) 

The upshot is that the flashrom ids are required to allow development
from the original bios.... for the time being.

Once the build is booting properly and flashrom can autodetect I will
remove the ids. In the mean time I'm hoping that having this early
flashrom support will help others to help in the effort for the
CN400/epia-n(l)/Luke.

If this is still all to immature for general release then fair enough,
it can wait until things are working better.

Thanks,
Jon
-----Original Message-----
From: Luc Verhaegen [mailto:libv at skynet.be] 
Sent: 19 June 2009 11:32
To: Harrison, Jon (SELEX GALILEO, UK)
Cc: coreboot at coreboot.org
Subject: Re: [coreboot] Flashrom support for EPIA-N(L) - patch for
review

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On Thu, Jun 18, 2009 at 01:05:40PM +0100, Harrison, Jon (SELEX GALILEO,
UK) wrote:
> I didn't mean to suggest that there is anything wroung with flashrom
> itself, there is either some issue with reading the coreboot tables
from
> the coreboot flash after booting from the stock flash (which I have to
> do all of the time at the moment) or my coreboot image is broken in
some
> way ... I've not had the hex editor out (yet) as I'm working more on
> getting the initial CN400 work done and personally I am quite happy
with
> having to -m at this stage of development.
> 
> I was keener to get the flashrom functionality that does work out
there,
> so that there is a minimum level of functionality available for anyone
> else out there that wants to start contributing to the development
> effort on this MB.
> 
> Of course this may all turn to be linked ..........

> On Thu, Jun 18, 2009 at 11:36:49AM +0100, Harrison, Jon (SELEX
GALILEO,
> UK) wrote:
> > 
> > Auto detection doesn't seem to be working properly and at this stage
> I'm
> > breaking things so much that the -m switch is necessary for reliable
> > operation.
> 
> Why doesn't it seem to work properly?
> 
> Luc Verhaegen.

Ok. communication error here.

You will only have the coreboot tables when coreboot has succesfully 
booted and your config has USE_OPTION_TABLE.

But... like with many of the other epia boards, you will never disable 
rom access from coreboot and therefor flashrom does not need to enable
specifically for this board.

So:

* original bios has an extra write disable, but also has subsystem ids.
  here flashrom should use the subsystem ids to autodetect this board.
* coreboot, from reset, should not touch set the board specific 
  disable. So flashrom doesn't need to know or touch this.
* when coreboot is ran after the normal bios, the subsystem ids usually
  still are there, and so is the write protection (if you're plugging 
  chips). Flashrom then should still autodetect through subsystem ids 
  still.

So, do you really need flashrom to run the board specific enable when 
you've booted coreboot? If not, remove the coreboot ids, and also make 
it impossible for people to randomly try board enables (through the 
command line) and accidentally hit this code.

I am quite happy with the rest of the code though.

Luc Verhaegen.

SELEX Sensors and Airborne Systems Limited
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL
A company registered in England & Wales.  Company no. 02426132
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