On Thursday, February 10, 2011 07:08:01 am Andrew Dyer wrote:
> On Thu, Feb 10, 2011 at 00:28, Aaron Williams
>
> <aaron.willi...@caviumnetworks.com> wrote:
> >> I would suggest to make sure any caching/prefetching stuff is off,
> >> hardware is doing one flash bus access per CPU read/write.
> >>
> >> In cmdset_amd_read_jedec_ids() after this line:
> >>
> >> manuId = flash_read_uchar (info, FLASH_OFFSET_MANUFACTURER_ID);
> >>
> >> add something like
> >>
> >> printf("test manf id word = %04x\n", *(volatile uint16_t *)0x1f400000);
> >> printf("test device id word = %04x\n", *(volatile uint16_t
> >> *)0x1f400002); printf("test device id word = %04x\n", *(volatile
> >> uint16_t *)0x1f40001c); printf("test device id word = %04x\n",
> >> *(volatile uint16_t *)0x1f40001e);
> >>
> >> and see what you get.
> >
> > fwc addr 1f400000 cmd f0 f0f0 16bit x 8 bit
> > flash_write16: address: 1f400000, value: 0xf0f0
> > fwc addr 1f401554 cmd aa aaaa 16bit x 8 bit
> > flash_write16: address: 1f401554, value: 0xaaaa
> > fwc addr 1f400aaa cmd 55 5555 16bit x 8 bit
> > flash_write16: address: 1f400aaa, value: 0x5555
> > fwc addr 1f401554 cmd 90 9090 16bit x 8 bit
> > flash_write16: address: 1f401554, value: 0x9090
> > flash_read8: address: 1f400001, value: 0x0
> > test manf id word = 1000
> > test device id word = 013f
> > test device id word = da6c
> > test device id word = 2926
>
> looks like garbage :-( What's in the flash at those addresses? Maybe
> something is happening to mess up the unlock sequence and you're
> reading the memory data instead of the device codes.
>
> It's odd that earlier in the sequence when the CFI query data is read
> the byte data is mirrored across both bytes of the response, here the
> two bytes are different.
I received an email back from Spansion about this problem. They suggested that
instead of the following:
fwc addr 1f401554 cmd aa aaaa 16bit x 8 bit
flash_write16: Wrote 0xaaaa to address 1f401554
funlock writing 0xaa to address 0x555
fwc addr 1f400aaa cmd 55 5555 16bit x 8 bit
flash_write16: Wrote 0x5555 to address 1f400aaa
fwc addr 1f401554 cmd 90 9090 16bit x 8 bit
flash_write16: Wrote 0x9090 to address 1f401554
to instead do the following:
write 0xAA to 0x1F400AAA
write 0x55 to 0x1F400555
write 0x90 to 0x1F400AAA
read 0x1F400001 returns 0x01
read 0x1F400003 returns 0x7e
This looks correct.
I found two things I need to do to work around the problem. First, in
flash_write_cmd I use info->chipwidth instead of info->portwidth for the write
commands, and second, in __flash_detect_cfi I don't modify the address in
compatibility mode. This works. If either of those steps are left out then
reading the manufacturer ID fails.
-Aaron
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