[PATCH] mtd: spi-nor: support eon en25qh256a variant

[Leon M. George]

Hello Michael and thanks for your reply :-)

I hope I'm doing this right (replying with send-email).

On Mon,  2 May 2022 13:52:27 +0200
Michael Walle <michael at walle.cc> wrote:

> 8m? It's a 32MiB flash right? So it should be the upper 16MiB?

You're absolutely right. The datasheet calls it the 'higher 128M bank' and
I mixed up the divisors 8 and 16 in my head - glorious!

> So the upper 16MiB never really worked, correct?

Correct. At least for the A variant.
I'm unsure about the no-A variant but I don't have one of those to test.
The information about accessing the higher bank is included in the commit
message just in case anyone wants to work on that.

I could imagine doing an attempt getting the EAR to work but I presume it
makes more sense if somebody with access to the hardware does it properly.

> Do you have the A variant only? Where did you get the SFDP from the
> non-A variant? datasheet?

I only have the A variant - yes - and the part about the datasheet is also
correct.
Sadly, the layout of the SFDP tables is different between the datasheets
but I went through them manually and most of the fields have identical
values.

These are the differences I can spot with my eyes:

        Value          |  address  |   A   |  no-A
-----------------------+-----------+-------+-------
 SFDP and table minor  |    0x04   | 0x06  | 0x00
   revision number     |  / 0x09   |       |
-----------------------+-----------+-------+-------
  param table length   |   0x0b    | 0x10  | 0x09
-----------------------+-----------+-------+-------
 supports 1-1-4 opcode |  0x32 at 7   |   1   |   0
-----------------------+-----------+-------+-------
  1-1-4 dummy clocks   |  0x3a at 0:5 |  0x4  | 0x0
-----------------------+-----------+-------+-------
   1-1-4 read opcode   |   0x3b    | 0x6b  | 0xFF
-----------------------+-----------+-------+-------
  sector type 2 size   |   0x4e    | 0x0f  | 0x00
-----------------------+-----------+-------+-------
 sector type 2 opcode  |   0x4f    | 0x52  | 0xff
-----------------------+-----------+-------+-------


The no-A variant datasheet doesn't list the following address ranges:

  0x10 - 0x1f
  0x54 - 0x63

I guess they'll read as 0xff.


> No need for the Tested-by:. That is already implied by the SoB (unless
> noted otherwise).

I will remove it then.

> Please also submit a SFDP dump, see [1].

Again, I hope I'm doing this right..

Thank you for your valued feedback :-)


kind regards,
Leon

---

$ xxd -p sfdp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$ md5sum sfdp
e4078f17a495a38c657f4f39f8851080  sfdp
$ cat jedec_id
1c7019
$ cat partname
en25qh256
$ cat manufacturer
eon