Re: [PATCH] mtd: spi-nor: micron-st: added support for np8p128ax60

[Andrea Zanotti]

Hi Michael,

I performed the test with drivers/misc/eeprom/at25.c.

I configured the DTS as such:
spi_pcm@0 {
compatible = "atmel,at25";
reg = <0>;
spi-max-frequency = <50000000>;
size = <16777216>;
pagesize = <64>;
address-width = <24>;
label = "micron_pcm";
};
and activated the driver itself in the kernel configuration.

I think the system is recognizing it:
# ls -l /sys/bus/spi/devices/spi0.0/eeprom
-rw-------    1 root     root      16777216 Jan  1 00:01
/sys/bus/spi/devices/spi0.0/eeprom

However, if I am not wrong (again, please correct me if I am wrong)
this driver does not
work with the MTD layer (I am booting with the following cmdline bootargs:
mtdparts=micron_pcm:128k(bootstrap),128k(fdt),10M(kernel/rootfs),-(spare)
and I expected to have the same partitions as before, but of course
they are missing.)

I am checking the Company ID on the document "JEP106BC", revisioned on
June 2020,
downloaded from here https://www.jedec.org/system/files/docs/JEP106BC.pdf.

STMicroelectronics should be 20
Micron should be 2C
Intel is advertised as 89, in Table 1 "Manufacturer's Identification Code".

How do you suggest to proceed?

Andrea

Il giorno mar 31 ago 2021 alle ore 17:05 Michael Walle
<michael@xxxxxxxx> ha scritto:
>
> Hi Andrea,
>
> Am 2021-08-31 12:11, schrieb Andrea Zanotti:
> > Il giorno mar 31 ago 2021 alle ore 11:09 Andrea Zanotti
> > <andreazanottifo@xxxxxxxxx> ha scritto:
> >>
> >> Hi Michael,
> >>
> >> Il giorno mar 31 ago 2021 alle ore 10:39 Michael Walle
> >> <michael@xxxxxxxx> ha scritto:
> >>>
> >>> Hi Andrea,
> >>>
> >>> Am 2021-08-31 10:13, schrieb Andrea Zanotti:
> >>> > From: Andrea Zanotti <andreazanottifo@xxxxxxxxx>
> >>> >
> >>> > Added support for P8P Parallel Phase Change Memory.
> >>>
> >>> Please use present tense, eg "add support..."
> >>>
> >>> Is there a public datasheet? If so, please include it above
> >>> your SoB like so:
> >>> Datasheet: https://...
> >>>
> >>
> >> I will format the header as per your suggestions. I used the same
> >> datasheet
> >> linked by you at the end of the email
> >>
> >>>
> >>> > Added memory information (page size and sector size) as per data-
> >>> > sheet information, after typos corrections.
> >>>
> >>> After typos corrections?
> >>>
> >>
> >> The one specified in the following paragraph. I'll better write this.
> >> (What I meant
> >> is that there are some typos in the datasheet itself)
> >>
> >>>
> >>> > At page 37, paragraph 'SPI Memory Organization', it is written
> >>> > down that the memory is organized as:
> >>> >  * 16.772.216 bytes (typo here, there 16.777.216 bytes)
> >>> >  * 128 sectors of 128 Kbytes each (correct)
> >>> >  * 131.072 pages of 64 bytes each (typo here, as the total would be
> >>> >    64Mbit, but the total memory is actually 128Mbit, correct value
> >>> >    is 262.144 pages)
> >>> >
> >>> > Patch tested against the aforementioned PCM memory.
> >>>
> >>> What SPI host controller was used?
> >>>
> >>
> >> I used an AT91SAM9G20 processor, SPI controller "atmel,at91rm9200-spi"
> >> (spi-atmel.c)
> >>
> >>>
> >>> > No known regressions inserted, as the patch only adds the possibility
> >>> > to recognize said PCM memory inside the common spi-nor driver.
> >>>
> >>> Please drop this. If there were any regressions, the patch wouldn't
> >>> be picked up anyway.
> >>>
> >>
> >> It will be dropped.
> >>
> >>> >
> >>> > Signed-off-by: Andrea Zanotti <andreazanottifo@xxxxxxxxx>
> >>> > ---
> >>> >  drivers/mtd/spi-nor/micron-st.c | 1 +
> >>> >  1 file changed, 1 insertion(+)
> >>> >
> >>> > diff --git a/drivers/mtd/spi-nor/micron-st.c
> >>> > b/drivers/mtd/spi-nor/micron-st.c
> >>> > index c224e59820a1..c78331451082 100644
> >>> > --- a/drivers/mtd/spi-nor/micron-st.c
> >>> > +++ b/drivers/mtd/spi-nor/micron-st.c
> >>> > @@ -128,6 +128,7 @@ static const struct flash_info micron_parts[] = {
> >>> >       { "mt35xu02g", INFO(0x2c5b1c, 0, 128 * 1024, 2048,
> >>> >                           SECT_4K | USE_FSR | SPI_NOR_OCTAL_READ |
> >>> >                           SPI_NOR_4B_OPCODES) },
> >>> > +     { "np8p128ax60", {0x89, 0xda, 0x18}, 3, 128 * 1024, 128, 64, 0, 0 },
> >>>
> >>> Eh? Please use INFO(). And why isn't this 0x20 for micron.
> >>>
> >>
> >> With INFO() macro I am locked in with .page_size = 256 (I would need
> >> 64), or am I missing something?
>
> Ok I see. Mh, then maybe there should be a new macro where you can
> set the page_size?
>
> >>>
> >>> I found this datasheet:
> >>> https://media.digikey.com/pdf/Data%20Sheets/Micron%20Technology%20Inc%20PDFs/NP8P128Ax60E_Rev_K.pdf
> >>>
> >>> According to that datasheet, the manuf id is 0x20. And the device id
> >>> should be either 0x88e1 or 0x8821.
> >>>
> >>
> >> You are right, checking it right now.
> >>
> >
> > - As per datasheet, table 10 on page 18, Manufacturer code is 0x89
> > (column "data" for parameter "Manufacturer Code").
>
> That is for the command 90h (which is for the parallel interface?). We
> issue 9Fh and according to the "READ IDENTIFICATION (RDID)" chapter:
>
>    The manufacturer identification is assigned by JEDEC and has the
>    value 20h for Micron.
>
> And in fact it is assigned by JEDEC, see below.
>
> > - On the datasheet, I agree with you that the device code is
> > advertised as either 0x88e1 or 0x8821. I changed the byte array
> > to something wrong in order to have the debug warning on the JEDEC id
> > bytes, and this is the log:
> >
> > spi-nor spi0.0: unrecognized JEDEC id bytes: 89 da 18 00 00 00
> >
> > Second and third byte are "0xda" and "0x18". I am not an expert in the
> > spi-nor driver, but from my understanding
> > (if it's wrong, please correct me) the spi-nor driver tries to match
> > the the read bytes from the memory with the ones
> > in the tables. I don't know if the datasheet is wrong also in that
> > cell of the table, or if I am interpreting the data wrongly.
>
> Looks like the datasheet is wrong or something is broken here. Yes
> you are correct in assuming that these are in fact the ID bytes.
>
> We'd need to check what vendor 0x89 is to avoid collisions with other
> vendors/flashes.
>
> Btw this "flash" has no need for an erase, just like the MRAM or an
> SPI EEPROM. Could you have a look at drivers/misc/eeprom/at25.c if
> that will work for you?
>
> -michael