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From:   Roy Pledge <roy.pledge@nxp.com>
To:     Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Leo Li <leoyang.li@nxp.com>
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        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] soc: fsl: qbman: qman_portal: defer probing when qman
 is not available
Thread-Topic: [PATCH 1/2] soc: fsl: qbman: qman_portal: defer probing when
 qman is not available
Thread-Index: AQHUOylQ2NNkF5RWl0WF1A0TtXJBEw==
Date:   Fri, 24 Aug 2018 14:52:02 +0000
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On 8/23/2018 5:36 PM, Alexandre Belloni wrote:=0A=
> If the qman driver (qman_ccsr) doesn't probe or fail to probe before=0A=
> qman_portal, qm_ccsr_start will be either NULL or a stale pointer to an=
=0A=
> unmapped page.=0A=
>=0A=
> This leads to a crash when probing  qman_portal as the init_pcfg function=
=0A=
> calls qman_liodn_fixup that tries to read qman registers.=0A=
>=0A=
> Assume that qman didn't probe when the pool mask is 0.=0A=
>=0A=
> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>=0A=
> ---=0A=
>  drivers/soc/fsl/qbman/qman_portal.c | 2 ++=0A=
>  1 file changed, 2 insertions(+)=0A=
>=0A=
> diff --git a/drivers/soc/fsl/qbman/qman_portal.c b/drivers/soc/fsl/qbman/=
qman_portal.c=0A=
> index a120002b630e..4fc80d2c8feb 100644=0A=
> --- a/drivers/soc/fsl/qbman/qman_portal.c=0A=
> +++ b/drivers/soc/fsl/qbman/qman_portal.c=0A=
> @@ -277,6 +277,8 @@ static int qman_portal_probe(struct platform_device *=
pdev)=0A=
>  	}=0A=
>  =0A=
>  	pcfg->pools =3D qm_get_pools_sdqcr();=0A=
> +	if (pcfg->pools =3D=3D 0)=0A=
> +		return -EPROBE_DEFER;=0A=
>  =0A=
>  	spin_lock(&qman_lock);=0A=
>  	cpu =3D cpumask_next_zero(-1, &portal_cpus);=0A=
=0A=
Reviewed-by: Roy Pledge <roy.pledge@nxp.com>=0A=
=0A=
=0A=