From: Michael Walle <michael@walle.cc>
To: Takahiro Kuwano <tkuw584924@gmail.com>
Cc: linux-mtd@lists.infradead.org, tudor.ambarus@microchip.com,
miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com,
p.yadav@ti.com, Bacem.Daassi@infineon.com,
Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Subject: Re: [PATCH v15 6/8] mtd: spi-nor: Retain nor->addr_width at 4BAIT parse
Date: Fri, 13 May 2022 11:40:35 +0200 [thread overview]
Message-ID: <0eea594f72858ec0ee099d45da71bc96@walle.cc> (raw)
In-Reply-To: <93de6975-c734-06d4-7865-bbe7f90cba4a@gmail.com>
[btw the subject still has the old name of the addr_width]
Am 2022-05-13 03:26, schrieb Takahiro Kuwano:
> On 5/13/2022 7:14 AM, Michael Walle wrote:
>> Am 2022-05-10 00:10, schrieb tkuw584924@gmail.com:
>>> From: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
>>>
>>> In 4BAIT parse, keep nor->params->addr_width because it may be used
>>> as
>>> current address mode in SMPT parse later on.
>>
>> Mh I'm not sure this is needed at all.
>>
>> SFDP spec says
>> Variable address length (the current setting of the address
>> length mode defines the address length)
>>
>> and
>> When the length is defined as variable, the software or hardware
>> controlling the memory is aware of the address length mode last
>> set in the memory device and this same length of address.
>>
>> We don't set any address mode until all the SFDP parsing is
>> over. Therefore we should always be in 3 byte mode, no?
>>
> Actually there are some devices that have variable address length but
> 4 byte mode by default (I will work on those devices after this series
> is settled). To support such case, I prefer to use params->addr_nbytes
> as current address mode so that I can fix it in post_bfpt_fixup() hook.
Are there public datasheets available? So these devices have a 3 byte
and a 4 byte mode, but after reset, they are in the 4 byte mode? Looks
like it should be fixed in a different way. I'm not sure the "current
mode" handling is correct.
We need to differentiate between the mode the flash currently is using
(nor->addr_nbytes) and the mode parsed by SFDP (params->addr_nbytes).
At some point, the mode is switched and nor->addr_nbytes becomes
params->addr_nbytes. It seems in your case nor->addr_nbytes should
be 4 right from the beginning. Which also means nor->addr_nbytes
should be 3 for the other cases (and probably not 0).
-michael
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next prev parent reply other threads:[~2022-05-13 9:41 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-09 22:10 [PATCH v15 0/8] mtd: spi-nor: Add support for Infineon s25hl-t/s25hs-t tkuw584924
2022-05-09 22:10 ` [PATCH v15 1/8] mtd: spi-nor: s/addr_width/addr_nbytes tkuw584924
2022-05-12 21:01 ` Michael Walle
2022-05-31 11:13 ` Pratyush Yadav
2022-05-09 22:10 ` [PATCH v15 2/8] mtd: spi-nor: core: Shrink the storage size of the flash_info's addr_nbytes tkuw584924
2022-05-12 21:22 ` Michael Walle
2022-05-31 11:14 ` Pratyush Yadav
2022-05-09 22:10 ` [PATCH v15 3/8] mtd: spi-nor: sfdp: Clarify that nor->read_{opcode, dummy} are uninitialized tkuw584924
2022-05-12 21:33 ` Michael Walle
2022-05-12 21:38 ` Michael Walle
2022-05-31 11:18 ` Pratyush Yadav
2022-05-09 22:10 ` [PATCH v15 4/8] mtd: spi-nor: Do not change nor->addr_nbytes at SFDP parsing time tkuw584924
2022-05-12 21:45 ` Michael Walle
2022-05-31 11:30 ` Pratyush Yadav
2022-07-21 14:32 ` Tudor.Ambarus
2022-07-21 15:02 ` Tudor.Ambarus
2022-05-09 22:10 ` [PATCH v15 5/8] mtd: spi-nor: core: Couple the number of address bytes with the address mode tkuw584924
2022-05-12 22:07 ` Michael Walle
2022-05-09 22:10 ` [PATCH v15 6/8] mtd: spi-nor: Retain nor->addr_width at 4BAIT parse tkuw584924
2022-05-12 22:14 ` Michael Walle
2022-05-13 1:26 ` Takahiro Kuwano
2022-05-13 9:40 ` Michael Walle [this message]
2022-05-14 3:51 ` Takahiro Kuwano
2022-05-18 6:04 ` Takahiro Kuwano
2022-05-18 8:35 ` Michael Walle
2022-05-18 9:12 ` Takahiro Kuwano
2022-05-23 7:49 ` Michael Walle
2022-05-23 9:56 ` Takahiro Kuwano
2022-06-03 9:33 ` Takahiro Kuwano
2022-07-21 16:06 ` Tudor.Ambarus
2022-07-22 4:00 ` Takahiro Kuwano
2022-07-22 4:20 ` Tudor.Ambarus
2022-07-22 4:31 ` Vanessa Page
2022-07-22 4:46 ` Takahiro Kuwano
2022-07-22 5:06 ` Tudor.Ambarus
2022-07-22 5:11 ` Takahiro Kuwano
2022-07-22 6:08 ` Tudor.Ambarus
2022-07-22 7:38 ` Tudor.Ambarus
2022-07-22 7:45 ` Tudor.Ambarus
2022-06-08 11:39 ` Tudor.Ambarus
2022-05-09 22:10 ` [PATCH v15 7/8] mtd: spi-nor: spansion: Add local function to discover page size tkuw584924
2022-05-09 22:10 ` [PATCH v15 8/8] mtd: spi-nor: spansion: Add s25hl-t/s25hs-t IDs and fixups tkuw584924
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