[flashrom] 64Mbit IS25LP064A not recognized

Nico Huber nico.huber at secunet.com
Tue Aug 28 13:51:34 CEST 2018


Hi Simon,

Am 28.08.18 um 10:51 schrieb Buhrow, Simon:
> Measuring the signal I got that the command given above does first a
> RDJDID Operation and later the RDSFDP operation (which should be
> according to JESD216).  I attach the signals. You can see the the
> operations and what is done.

it seems to me that flashrom has already processed parts of the SFDP
(5a 00 00 54 means it requests data at offset 0x54 of the SFDP, right?).
You can probably see more details about why it fails if you add one or
two -V to your flashrom command.

> According to the datasheet is MF7-MF0: 9Dh
> and Memory Type + Capacity (ID15 - ID0): 6017h. Which you can see on the
> RDJDID signals image.
> 
> I know the signal quality is not the best but doing real improves would
> cost a lot of time. As I already successfully programmed another
> supported chip and because the Flash chip response the right way I think
> that it´s not a signal integrity problem.
> 
> So my questions are:
> 1)      Does "unknown SPI chip (RDID)" mean "it´s not in the database"
> or does it mean "RDID could not be read successfully"?

It can mean both as the protocol has no means of error detection. It's
simply: the MISO level wasn't all zero, IIRC.

You can see the response if you add -V to your command. It should print
id1:... id2:... for each chip probed. For all RDID commands this should
be consistently the 0x9d 0x6017 of your chip.

> 2)      If it means "RDID could not be read successfully": Is there any
> other possibility than signal integrity why flashrom does not show the
> right RDID?

The programmer is a black box to flashrom, anything in there might fail
too. But assuming absence of bugs and that the programmer works nor-
mally, no.

> 3)      If it means "it´s not in the database":  Would adding it to the
> database solve the problem or is that not crucial?

Likely, yes. And it's not much work, IS25LP128 is already in the
database. If you are lucky, it's just copying that entry and adapting
sizes. Let us know if you need help with that.

> 4)      Does flashrom supports flashs with memory of 64Mbit? As I can´t
> find any in the supported hardware list.

A lot. The `Size` column in that list is given in kB, 64Mbit is 8192kB.

> Btw: the JESD216 link at https://www.flashrom.org/Supported_hardware
> does not work. May be
> https://www.jedec.org/standards-documents/docs/jesd216b is what should
> be linked?

I never looked at flashrom's SFDP code, but somebody told me once it's
written against some earlier spec. Probably needs some more investi-
gation before we point to a version that is not implemented at all.

Nico
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