Re: [PATCH v2 1/1] mtd: spi-nor: micron-st: Enable locking for n25q256ax1/mt25qu256a

[Michael Walle]

Am 2022-10-19 11:52, schrieb Farber, Eliav:
> On 10/19/2022 12:38 PM, Michael Walle wrote:
> > Am 2022-10-19 11:25, schrieb Farber, Eliav:
> > > On 10/19/2022 11:21 AM, Michael Walle wrote:
> > > > Hi,
> > > >
> > > > Am 2022-10-19 09:16, schrieb Eliav Farber:
> > > > > n25q256ax1 [1] and mt25qu256a [2] (both have same jedec_id -
> > > > > 0x20bb19)
> > > > > use the 4 bit Block Protection scheme and support Top/Bottom
> > > > > protection
> > > > > via the BP and TB bits of the Status Register.
> > > > > BP3 is located in bit 6 of the Status Register.
> > > > > Tested on both n25q256ax1 and mt25qu256a.
> > > > >
> > > > > [1]
> > > > > https://www.micron.com/-/media/client/global/documents/products/data-sheet/nor-flash/serial-nor/n25q/n25q_256mb_3v.pdf 
> > > > > [2]
> > > > > https://www.micron.com/-/media/client/global/documents/products/data-sheet/nor-flash/serial-nor/mt25q/die-rev-a/mt25q_qljs_u_256_aba_0.pdf
> > > >
> > > > If you respin, you can use a "Link:" tag for the URL above.
> > >
> > > Ack.
> > >
> > > > > Signed-off-by: Eliav Farber <farbere@xxxxxxxxxx>
> > > > > ---
> > > > > xxd -p
> > > > > /sys/devices/platform/soc/fd882000.spi/spi_master/spi0/spi0.0/spi-nor/sfdp 
> > > > > 53464450060101ff00060110300000ff84000102800000ffffffffffffff
> > > > > ffffffffffffffffffffffffffffffffffffe520fbffffffff0f29eb276b
> > > > > 273b27bbffffffffffff27bbffff29eb0c2010d80f520000244a99008b8e
> > > > > 03d4ac0127387a757a75fbbdd55c4a0f82ff81bd3d36ffffffffffffffff
> > > > > ffffffffffffffffffe7ffff21dcffff
> > > > >
> > > > > md5sum
> > > > > /sys/devices/platform/soc/fd882000.spi/spi_master/spi0/spi0.0/spi-nor/sfdp 
> > > > > 5ea738216f68c9f98987bb3725699a32
> > > > > /sys/devices/platform/soc/fd882000.spi/spi_master/spi0/spi0.0/spi-nor/sfdp 
> > > > > cat
> > > > > /sys/devices/platform/soc/fd882000.spi/spi_master/spi0/spi0.0/spi-nor/jedec_id 
> > > > > 20bb19104400
> > > > >
> > > > > cat
> > > > > /sys/devices/platform/soc/fd882000.spi/spi_master/spi0/spi0.0/spi-nor/partname 
> > > > > mt25qu256a
> > > > >
> > > > > cat
> > > > > /sys/devices/platform/soc/fd882000.spi/spi_master/spi0/spi0.0/spi-nor/manufacturer 
> > > > > st
> > > >
> > > > That's the mt25qu256a SFDP. What about the n25q256ax1?
> > >
> > > On the same card, with same NOR flash memory I'm running two 
> > > different
> > > kernel versions.
> > > First version is quite old - 4.19.239 which does not support 
> > > mt25qu256a
> > > and therefore device is detected as n25q256ax1.
> > > Second version is 6.1.0-rc1 and it detects the same device as
> > > mt25qu256a.
> > > So I was able to dump SFDP when running version 6.1.0-rc1, but not 
> > > when
> > > running 4.19.239 which does not support the sysfs to dump the SFPD
> > > information.
> > > I checked that locking works with my changes when running on both
> > > kernel
> > > versions.
> >
> > So you've only tested on an mt25qu256a, correct? Then you should only
> > add the locking to this flash device. (and maybe backport the 
> > mt25qu256a
> > to your older kernel).
>
> I dumped SFDP tables only for mt25qu256a, but as I mentioned I tested
> locking functionality for both (on 4.19.239 which detects the device as
> n25q256ax1 and on 6.1.0-rc1  which detects the device as mt25qu256a).
> This is the flow I used for testing the change on both versions:

You said you've tested on the same board, thus it has the same flash
device. But with the older kernel it was detected as a different part.

So the question is, what is the correct part number? I.e. what is the
_actual_ flash device soldered on your board?

-michael