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Date:   Wed, 21 Dec 2022 09:22:04 +0100
From:   Michael Walle <michael@walle.cc>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Sudip Mukherjee <sudip.mukherjee@sifive.com>,
        Tudor Ambarus <tudor.ambarus@microchip.com>,
        Pratyush Yadav <pratyush@kernel.org>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>, greentime.hu@sifive.com,
        jude.onyenegecha@sifive.com, william.salmon@sifive.com,
        adnan.chowdhury@sifive.com, ben.dooks@sifive.com,
        linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/2] mtd: spi-nor: issi: is25wp256: Init flash based on
 SFDP
In-Reply-To: <20221221003009.GA280250@roeck-us.net>
References: <20220920184808.44876-1-sudip.mukherjee@sifive.com>
 <20221221003009.GA280250@roeck-us.net>
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Hi,

Am 2022-12-21 01:30, schrieb Guenter Roeck:
> With this patch in place, qemu emulations with is25wp256 fail to
> instantiate the flash. Specifically, this affects the qemu sifive_u
> emulation. The resulting error message is:
> 
> spi-nor spi0.0: BFPT parsing failed. Please consider using
> SPI_NOR_SKIP_SFDP when declaring the flash
> spi-nor: probe of spi0.0 failed with error -22

qemu is to blame here. It doesn't fully emulate the flash. Esp. not
the SFDP tables. See also [1]. Adding the .sfdp_read hook with the
corresponding binary [2] should fix your issue.

[1] 
https://lore.kernel.org/qemu-devel/7827c791b7f91f4eb216b33473dd6103@walle.cc/
[2] 
https://lore.kernel.org/linux-mtd/CAHyZL-ch=mr0x_19e6P9G+Z4sW2iJXW9nTnXUNAhn+pTptN2ww@mail.gmail.com/

-michael