[Qemu-devel] Re: Commit 9c9bb6c89d4 breaks code execution from flash

[Michael Walle]

Am Thursday 13 May 2010 09:38:43 schrieb Jan Kiszka:
> > But i noticed another minor bug. The cfi02 doesn't handle 'read flash id'
> > on 16bit accesses correctly. It always returns 8 bit. I used something
> > like
> >
> > if (width == 2)
> >     ret = pfl->ident[0] << 8 | pfl->ident[1];  /* rsp. ident[1]/ident[2]
> > */
> >
> > within the 0x90 reading as a quick workaround.
>
> Are you sure that this is valid? The whole cfi_table is also only
> provided byte-wise, same in cfi01.

At least the JEDEC ID read returns 16 bit values with x16 devices. Have a look 
at:
  http://www.spansion.com/Support/Datasheets/s29gl128_256n_sp_a2_e.pdf
  Table II on page 51

micromonitor (the program i tested with) and uboot uses 16bit reads to read 
the flash id. Have a look at
http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=blob;f=drivers/mtd/cfi_flash.c;h=3267c5de36d1b12a190f93f9a3048ded598f84aa;hb=HEAD#l1535

-- 
wkr michael