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

[Michael Walle]

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).

-michael