[U-Boot-Users] Re: [PATCH][CFT] bring ARM memory layout in line with the documented behaviour

From: Wolfgang Denk <wd@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot-Users] Re: [PATCH][CFT] bring ARM memory layout in line with the documented behaviour
Date: Thu, 18 Sep 2003 23:20:29 +0200	[thread overview]
Message-ID: <20030918212034.CF477C59E4@atlas.denx.de> (raw)
In-Reply-To: Your message of "Thu, 18 Sep 2003 14:15:21 +0200." <fc.004c4e48001cc2803b9aca007685644e.1cc321@rea.de>

Dear Anders,

in message <fc.004c4e48001cc2803b9aca007685644e.1cc321@rea.de> you wrote:
> 
> are you saying that the patch doesn't go far enough?
> (I feared that the patch might have gone too far :-)

No, I didn't want to say that.I think the patch is pretty good as is,
separating one step can can be done indeoend of the other  things.  I
just  wanted  to  point out that this is only part of the tasks which
are ahead of us.

> It looks like a substantial amount of work to implement your wishes (but
> its doable, I believe).

Yes, it's some work; the most difficult thing is to verify that  such
changes don;t break any of the existing ports - and some of these are
pretty  complex  and feature-rich. Complete re-testing just one board
may well take a man-week or more...

> Would you accept the patch as is as a first step in that direction (in
> order not to change too much in one step) provided the other ARM board
> maintainers don't object?

Yes, I will.

> Furthermore, the startup code (cpu/<arm>/start.S) internally uses
> another variable (_TEXT_BASE) with the same content as _armboot_start.
> I agree that this mess should be cleaned up.

Fine. Let's remember this for the next step, then.

> _armboot_end is the end address of the BSS and is used to determine
> the address of the VFD buffer.

This not optimal. Ideally, the display buffer would be located at the
very end of memory (BTW: the same is  true  for  the  log  buffer  if
configured), and U-Boot below it.

> Again, my available HW doesn't have a display, so I can't test it.
> I'll take a look at it anyway, though.

Well, you probably can test with the log buffer enabled and check  if
the  log buffer information can be passed to the Linux kernel (umm...
I think this hasn't been tried ever on an ARM system)

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
We, the unwilling, led by the unknowing, are doing the impossible for
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