From: Pratyush Yadav <p.yadav@ti.com>
To: "Matthias Weißer" <m.weisser.m@gmail.com>
Cc: vigneshr@ti.com, sergei.shtylyov@cogentembedded.com,
tudor.ambarus@microchip.com, richard@nod.at,
me@yadavpratyush.com, john.garry@huawei.com, linuxarm@huawei.com,
Yicong Yang <yangyicong@hisilicon.com>,
linux-mtd@lists.infradead.org, miquel.raynal@bootlin.com,
alexander.sverdlin@nokia.com
Subject: Re: [PATCH 2/2] mtd: spi-nor: Disable the flash quad mode in spi_nor_restore()
Date: Tue, 1 Sep 2020 15:18:18 +0530 [thread overview]
Message-ID: <20200901094816.ddw2do2ryjvqvasq@ti.com> (raw)
In-Reply-To: <CAO8h3eFLVLRmw7u+rurKsg7=Nh2q-HVq-HgVXig8gf5Dffk8MA@mail.gmail.com>
Hi,
On 01/09/20 08:16AM, Matthias Weißer wrote:
> Am Di., 16. Juni 2020 um 15:03 Uhr schrieb Yicong Yang
> <yangyicong@hisilicon.com>:
> > If the flash's quad mode is enabled, it'll remain in the quad mode when
> > it's removed. If we drive the flash next time in SPI/Dual mode, then
> > problem occurs as the flash's quad enable bit is not cleared.
>
> On flash devices with a non-volatile quad enable bit (we use S25FL512S)
> this will wear out the quad enable bit as on every boot the bit is
> set and reset on shutdown. Or do I miss something here?
Yes, I think it will. If you always want the bit enabled (and it being
non-volatile suggests that is the intended use), why not set
nor->params->quad_enable() to NULL? That way it won't be touched at all,
neither on boot nor on shutdown.
> > Disable the quad mode in spi_nor_restore(), the flash will leave
> > quad mode when remove. This will make sure the flash always enter the
> > correct mode when loaded.
>
> We have a system which relies on an enabled quad mode on boot
> (bootloader uses quad mode without enabling it) so using this patch
> will prevent our device from booting.
Out of curiosity, how does the flash get detected by SPI NOR? It issues
the Read ID command in 1S-1S-1S mode but the flash is expecting 1S-4S-4S
commands. Do you have any extra patches applied to make it work?
I tried solving this problem for 8D-8D-8D mode but never really found a
good solution.
--
Regards,
Pratyush Yadav
Texas Instruments India
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next prev parent reply other threads:[~2020-09-01 9:49 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-16 13:02 [PATCH 0/2] Add support to Disable the flash quad mode Yicong Yang
2020-06-16 13:02 ` [PATCH 1/2] mtd: spi-nor: Add capability to disable " Yicong Yang
2020-07-02 11:07 ` Tudor.Ambarus
2020-06-16 13:02 ` [PATCH 2/2] mtd: spi-nor: Disable the flash quad mode in spi_nor_restore() Yicong Yang
2020-07-02 11:02 ` Tudor.Ambarus
2020-07-03 11:19 ` Pratyush Yadav
2020-07-03 11:52 ` Tudor.Ambarus
2020-07-06 6:47 ` Yicong Yang
2020-09-01 6:16 ` Matthias Weißer
2020-09-01 9:48 ` Pratyush Yadav [this message]
2020-09-01 10:08 ` Matthias Weißer
2020-09-01 11:11 ` Pratyush Yadav
2020-09-01 11:41 ` Yicong Yang
2020-09-01 14:20 ` Yicong Yang
2020-09-02 7:50 ` Vignesh Raghavendra
2020-09-02 10:12 ` Yicong Yang
2020-09-03 5:59 ` Vignesh Raghavendra
2020-09-04 7:54 ` Yicong Yang
2020-09-04 9:35 ` Matthias Weißer
2020-09-02 12:15 ` Matthias Weißer
2020-09-03 3:03 ` Yicong Yang
2020-09-03 5:33 ` Matthias Weißer
2020-09-04 7:56 ` Yicong Yang
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