[U-Boot] [PATCH 1/3] ARM: don't panic if no flash is there

[Wolfgang Denk]

Dear Alessandro Rubini,

In message <20110417173205.GA28105 at mail.gnudd.com> you wrote:
> 
> > If you do not have NOR flash, then you should not enable it (and
> > define CONFIG_SYS_NO_FLASH). Otherwise, you are supposed to have
> > flash memory.
> 
> I expect a serious boot loader to work in all possible situations and
> to be a development tool, the thing that was called a monitor ages ago
> (why do you have "mw" and "md" otherwise?). I've always loved u-boot
> usefulness as opposed to the crappy "do nothing at all" wince or
> freecale boot loaders.

You know that all this is just polemics, as in your special case none
of your arguments actually applies.

> Thus, I see three reasons to revert the older behaviour.

We want to unify the code across architectures.  The behavior we have
now is what we have in U-Boot (and PPCBoot) since day one, i. e. for
well over a decade.  The problem was just that some architectures
incorrectly implemented this, and such bugs got finally fixed.

> - even if flash got broken over time, the machine should be useable.
> hang() here gains nothing, as I may still be able to boot though the net
> and see what happens, without the need to recompile and reflesh a special
> recovery boot loader

If you have a system with NOR flash, you usually boot from NOR.  If
NOR is so broken that it fails the detection, you cannot make any
assumptions about which code might be running, and which not.  You
have fully undefined behaviour then.  In such a situation it is best
to shut the system down and halt in a safe mode, instead of running
any random code.  Many of these devices actually control hardware,
where uncontrolled misfunction might be dangerous.

I'm sorry, but my decision is made.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The number you have dialed is imaginary. Please divide by 0  and  try
again.