[flashrom] [RFC, PATCH] Add read support for the Spansion S25FL129P flash chip

[Stefan Tauner]

On Wed, 26 Sep 2012 13:50:54 +0200
Antonio Ospite <ospite at studenti.unina.it> wrote:

> http://www.spansion.com/Support/Datasheets/S25FL129P_00.pdf
> http://www.spansion.com/Support/Application%20Notes/S25FL129P_Prog_Guide_AN.pdf
> 
> Signed-off-by: Antonio Ospite <ospite at studenti.unina.it>
> ---
> 
> Hi,

hello and thanks a lot for your patch!

> I was able to read the content of the flash chip in the subject with the patch
> below but I am not sure if the patch is correct and ready for submission,
> could someone please check with the datasheet? I know very little about flash
> chips.

i pity you, because that chip is not one of the more simple ones, but
your patch seems to be ok on the first look. :) i need to look more
closely at it, after we fix the probing...

> Moreover from the Datasheet (Table 9.2, page 34) I see that this chip comes in
> two variants, one with 64K sectors and one with 256KB sectors,

that's quite a problem. while flashrom would not care too much, because
it just tries all erase functions available in cases of failure, we
usually do not merge such patches without being able to differentiate
between the chips (which sometimes requires to get very creative :).

> and some
> "Extended Device Identification" is used to identify the right variant,
> I don't know if flashrom supports reading such information.

in your case it is easier as you have found out already. flashrom does
not support EDI yet, but i am working on it. because flashrom supports
some very funky SPI masters (which have very annoying limitations on the
number of bytes to read and write in a single transaction) it is not
completely trivial to add this though. after that we can add the two(!)
chips from your patch (and maybe there exist other similar chips of
the same family with different capacities... have you looked for them?).

> I see that somewhere else that is supported:
> http://old.nabble.com/-PATCH--m25p80:-Add-Spansion-S25FL129P-serial-flashes-td25518109.html

that "somewhere" is actually the linux kernel ;)

> I didn't feel like testing erase/write either as the connection to the chip
> was/is quite unreliable, I just needed to get a rootfs off from it once (it's
> some embedded router). If anyone can suggest some really cheap place where to
> get test clips or probes in Italy (or even better feels like donating some),
> I might risk testing erase/write after we solve the issue about the chip
> variant.

you did not say which package, but i presumed SOIC8. apparently the
chip is only available as 300mil SOIC16 (and BGA/WSON). for SOIC8 i
would have written the following (i actually did write it before
checking... meh. maybe you find it useful nonetheless, if not just skip
over the next paragraph please :)

in that case the cheapest one is probably a Pomona 5250; 3M does also
make them, but they are usually more expensive.
someone from italy in our IRC channel has ordered one lately but it did
not arrive yet afaik. maybe he is near enough and willing to share :)
he ordered from here:
http://www.tme.eu/html/EN/soic08-test-clips/ramka_4886_EN_pelny.html
distrelec does also have them (i got mine from their austrian branch):
https://www.distrelec.it/pinzette-di-test-per-ic/pomona/5250/652964

for the SOIC16 the Pomona model number is 5252, tme does not seem to
have it but distrelec does and probably also any other electronics
reseller (mouser, rs, farnell etc).

PS: i have committed some ft2232_spi changes lately (r1608 - r1610). i
would be glad if you would upgrade and report if you have any issues
with them.

-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner