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Date:   Tue, 4 Jul 2023 17:21:41 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     William Zhang <william.zhang@broadcom.com>
Cc:     Broadcom Kernel List <bcm-kernel-feedback-list@broadcom.com>,
        Linux MTD List <linux-mtd@lists.infradead.org>,
        f.fainelli@gmail.com, rafal@milecki.pl, kursad.oney@broadcom.com,
        joel.peshkin@broadcom.com, computersforpeace@gmail.com,
        anand.gore@broadcom.com, dregan@mail.com, kamal.dasu@broadcom.com,
        tomer.yacoby@broadcom.com, dan.beygelman@broadcom.com,
        Florian Fainelli <florian.fainelli@broadcom.com>,
        linux-kernel@vger.kernel.org,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Richard Weinberger <richard@nod.at>,
        Boris Brezillon <bbrezillon@kernel.org>,
        Kamal Dasu <kdasu.kdev@gmail.com>
Subject: Re: [PATCH v3 2/5] mtd: rawnand: brcmnand: Fix potential false time
 out warning
Message-ID: <20230704172141.1369c9e8@xps-13>
In-Reply-To: <20230627193738.19596-3-william.zhang@broadcom.com>
References: <20230627193738.19596-1-william.zhang@broadcom.com>
        <20230627193738.19596-3-william.zhang@broadcom.com>
Organization: Bootlin
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Hi William,

william.zhang@broadcom.com wrote on Tue, 27 Jun 2023 12:37:35 -0700:

> If system is busy during the command status polling function, the driver
> may not get the chance to poll the status register till the end of time
> out and return the premature status.  Do a final check after time out
> happens to ensure reading the correct status.
>=20
> Fixes: 9d2ee0a60b8b ("mtd: nand: brcmnand: Check flash #WP pin status bef=
ore nand erase/program")
> Signed-off-by: William Zhang <william.zhang@broadcom.com>
> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>

Cc: stable here and in patch 1 as well.

> ---
>=20
> Changes in v3: None
> Changes in v2: None
>=20
>  drivers/mtd/nand/raw/brcmnand/brcmnand.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>=20
> diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/=
raw/brcmnand/brcmnand.c
> index 69709419516a..37c2c7cfa00e 100644
> --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> @@ -1080,6 +1080,14 @@ static int bcmnand_ctrl_poll_status(struct brcmnan=
d_controller *ctrl,
>  		cpu_relax();
>  	} while (time_after(limit, jiffies));
> =20
> +	/*
> +	 * do a final check after time out in case CPU is busy and driver does
> +	 * not get the enough time to poll to avoid false alarm

Do a final... ...the CPU was busy and the driver did not get enough
time to perform the polling to avoid false alarms.

> +	 */
> +	val =3D brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS);
> +	if ((val & mask) =3D=3D expected_val)
> +		return 0;
> +
>  	dev_warn(ctrl->dev, "timeout on status poll (expected %x got %x)\n",
>  		 expected_val, val & mask);
> =20

Otherwise looks good.

Thanks,
Miqu=C3=A8l