From:   Peng Fan <peng.fan@nxp.com>
To:     Stephan Gerhold <stephan@gerhold.net>,
        Shawn Guo <shawnguo@kernel.org>
CC:     Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        dl-linux-imx <linux-imx@nxp.com>,
        =?iso-8859-1?Q?Jonathan_Neusch=E4fer?= <j.neuschaefer@gmx.net>,
        Sebastian Reichel <sebastian.reichel@collabora.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Arnd Bergmann <arnd@arndb.de>
Subject: RE: [PATCH] soc: imx: Register SoC device only on i.MX boards
Thread-Topic: [PATCH] soc: imx: Register SoC device only on i.MX boards
Thread-Index: AQHX6pYUsoprkzANFkGiGnubfC+N9KwlYphg
Date:   Mon, 6 Dec 2021 12:23:04 +0000
Message-ID: <DU0PR04MB9417887E5C06F599C2048B14886D9@DU0PR04MB9417.eurprd04.prod.outlook.com>
References: <20211206113828.42523-1-stephan@gerhold.net>
In-Reply-To: <20211206113828.42523-1-stephan@gerhold.net>
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> Subject: [PATCH] soc: imx: Register SoC device only on i.MX boards
>=20
> At the moment, using the ARM32 multi_v7_defconfig always results in two
> SoCs being exposed in sysfs. This is wrong, as far as I'm aware the Qualc=
omm
> DragonBoard 410c does not actually make use of a i.MX SoC. :)
>=20
>   qcom-db410c:/sys/devices/soc0$ grep . *
>   family:Freescale i.MX
>   machine:Qualcomm Technologies, Inc. APQ 8016 SBC
>   revision:0.0
>   serial_number:0000000000000000
>   soc_id:Unknown
>=20
>   qcom-db410c:/sys/devices/soc1$ grep . *
>   family:Snapdragon
>   machine:APQ8016
>   ...
>=20
> This happens because imx_soc_device_init() registers the soc device
> unconditionally, even when running on devices that do not make use of i.M=
X.
> Arnd already reported this more than a year ago and even suggested a fix
> similar to this commit, but for some reason it was never submitted.
>=20
> Fix it by checking if the "__mxc_cpu_type" variable was actually initiali=
zed by
> earlier platform code. On devices without i.MX it will simply stay 0.
>=20
> Cc: Peng Fan <peng.fan@nxp.com>
> Fixes: d2199b34871b ("ARM: imx: use device_initcall for
> imx_soc_device_init")
> Reported-by: Arnd Bergmann <arnd@arndb.de>
> Link:
> https://eur01.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2Flore.=
ke
> rnel.org%2Fr%2FCAK8P3a0hxO1TmK6oOMQ70AHSWJnP_CAq57YMOutrxkSY
> NjFeuw%40mail.gmail.com%2F&amp;data=3D04%7C01%7Cpeng.fan%40nxp.co
> m%7Cba6334562b49404f88b708d9b8ad36b5%7C686ea1d3bc2b4c6fa92cd9
> 9c5c301635%7C0%7C0%7C637743876348146819%7CUnknown%7CTWFpbG
> Zsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6
> Mn0%3D%7C3000&amp;sdata=3DmAeB%2FvXO4cUbcPPLBH14LkDzxMz2w5SLj
> iNEZhjgFuU%3D&amp;reserved=3D0
> Signed-off-by: Stephan Gerhold <stephan@gerhold.net>

Reviewed-by: Peng Fan <peng.fan@nxp.com>

> ---
>  drivers/soc/imx/soc-imx.c | 4 ++++
>  1 file changed, 4 insertions(+)
>=20
> diff --git a/drivers/soc/imx/soc-imx.c b/drivers/soc/imx/soc-imx.c index
> ac6d856ba228..77bc12039c3d 100644
> --- a/drivers/soc/imx/soc-imx.c
> +++ b/drivers/soc/imx/soc-imx.c
> @@ -36,6 +36,10 @@ static int __init imx_soc_device_init(void)
>  	int ret;
>  	int i;
>=20
> +	/* Return early if this is running on devices with different SoCs */
> +	if (!__mxc_cpu_type)
> +		return 0;
> +
>  	if (of_machine_is_compatible("fsl,ls1021a"))
>  		return 0;
>=20
> --
> 2.34.1