[U-Boot] [PATCH] post: new parallel nor flash test

[Wolfgang Denk]

Dear Mike Frysinger,

In message <201105101711.07625.vapier at gentoo.org> you wrote:
>
> > > This adds a simple parallel nor flash test to automatically verify
> > > erasing/writing/reading of sectors.  The code is based on existing
> > > Blackfin tests but generalized for everyone to use.
> > 
> > What exactly does the "parallel" in "parallel nor flash test" mean?
> 
> how it is connected to the processor

Are there any other types of NOR flashes?  I mean, I have never heard
anybody use this term before.  Maybe we can just omit it - I find it
more confusing than helpful.

> > > +	unsigned char *ret = (void *)CONFIG_SYS_SDRAM_BASE;
> > 
> > This will not work on many systems.  For example, on PPC you will
> > overwrite the exception vectors in low memory, thus crashing the
> > system.
> 
> this is how the default memory post test works.  it writes all memory from
> CONFIG_SYS_SDRAM_BASE to CONFIG_SYS_SDRAM_BASE+MIN(1GiB,bd->memsize).  so how 
> does this work on ppc systems ?

The RAM test runs before relocation to RAM, i. e. whenRAM is still not
used by anything.

> i didnt think calling malloc() would be OK since i need enough memory to hold 
> one sector ...

Just grabbing a random address in RAM is certainly not a proper way
to allocate I/O buffers.  If you need them, and if your code design
makes it even necessary to pass these buffers around (so you can not
just put them on the stack which is what I would try to do) you have
to use malloc().

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 only way to learn a new programming language is by  writing  pro-
grams in it.                                        - Brian Kernighan