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Subject: Re: [PATCH v2 1/1] mtd: spi-nor: micron-st: Enable locking for
 n25q256ax1/mt25qu256a
Message-ID: <1ba2e7ff-cf6c-1292-72e0-14b5b5b9282c@amazon.com>
Date:   Wed, 19 Oct 2022 12:25:36 +0300
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To:     Michael Walle <michael@walle.cc>
CC:     <tudor.ambarus@microchip.com>, <pratyush@kernel.org>,
        <miquel.raynal@bootlin.com>, <richard@nod.at>, <vigneshr@ti.com>,
        <linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <talel@amazon.com>, <jonnyc@amazon.com>, <hhhawa@amazon.com>,
        <hanochu@amazon.com>, <itamark@amazon.com>, <shellykz@amazon.com>,
        <amitlavi@amazon.com>, <dkl@amazon.com>,
        "Farber, Eliav" <farbere@amazon.com>
References: <20221019071631.15191-1-farbere@amazon.com>
 <73bfa5ae90e2269387540019806c2839@walle.cc>
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From:   "Farber, Eliav" <farbere@amazon.com>
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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@amazon.com>
>> ---
>> 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.

--
Regards, Eliav