linux-kernel - RE: [PATCH v1 1/1] platform/x86: p2sb: Don't fail if unknown CPU is found

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Date:   Fri, 4 Nov 2022 15:58:22 +0000
From:   "Limonciello, Mario" <Mario.Limonciello@....com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Hans de Goede <hdegoede@...hat.com>,
        "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Mark Gross <markgross@...nel.org>,
        Jarkko Nikula <jarkko.nikula@...ux.intel.com>
Subject: RE: [PATCH v1 1/1] platform/x86: p2sb: Don't fail if unknown CPU is
 found

[Public]

> -----Original Message-----
> From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Sent: Friday, November 4, 2022 10:49
> To: Hans de Goede <hdegoede@...hat.com>; Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com>; platform-driver-
> x86@...r.kernel.org; linux-kernel@...r.kernel.org
> Cc: Mark Gross <markgross@...nel.org>; Jarkko Nikula
> <jarkko.nikula@...ux.intel.com>
> Subject: [PATCH v1 1/1] platform/x86: p2sb: Don't fail if unknown CPU is
> found
> 
> We have accessing P2SB from a very few places for quite known hardware.
> 
> When a new SoC appears in intel-family.h it's not obvious that it needs
> to be added to p2sb.c as well. Instead, provide default BDF and refactor
> p2sb_get_devfn() to always succeed. If in the future we would need to
> exclude something, we may add a list of unsupported IDs.
> 
> Without this change the iTCO on Intel Commet Lake SoCs became

Isn't it "Comet Lake"?

> unavailable:
> 
>   i801_smbus 0000:00:1f.4: failed to create iTCO device
> 
> Fixes: 5c7b9167ddf8 ("i2c: i801: convert to use common P2SB accessor")
> Reported-by: Jarkko Nikula <jarkko.nikula@...ux.intel.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  drivers/platform/x86/p2sb.c | 15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/platform/x86/p2sb.c b/drivers/platform/x86/p2sb.c
> index 384d0962ae93..1cf2471d54dd 100644
> --- a/drivers/platform/x86/p2sb.c
> +++ b/drivers/platform/x86/p2sb.c
> @@ -19,26 +19,23 @@
>  #define P2SBC			0xe0
>  #define P2SBC_HIDE		BIT(8)
> 
> +#define P2SB_DEVFN_DEFAULT	PCI_DEVFN(31, 1)
> +
>  static const struct x86_cpu_id p2sb_cpu_ids[] = {
>  	X86_MATCH_INTEL_FAM6_MODEL(ATOM_GOLDMONT,
> 	PCI_DEVFN(13, 0)),
> -	X86_MATCH_INTEL_FAM6_MODEL(ATOM_GOLDMONT_D,
> 	PCI_DEVFN(31, 1)),
> -	X86_MATCH_INTEL_FAM6_MODEL(ATOM_SILVERMONT_D,
> 	PCI_DEVFN(31, 1)),
> -	X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE,
> 	PCI_DEVFN(31, 1)),
> -	X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE_L,
> 	PCI_DEVFN(31, 1)),
> -	X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE,
> 	PCI_DEVFN(31, 1)),
> -	X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_L,
> 	PCI_DEVFN(31, 1)),
>  	{}
>  };
> 
>  static int p2sb_get_devfn(unsigned int *devfn)
>  {
> +	unsigned int fn = P2SB_DEVFN_DEFAULT;
>  	const struct x86_cpu_id *id;
> 
>  	id = x86_match_cpu(p2sb_cpu_ids);
> -	if (!id)
> -		return -ENODEV;
> +	if (id)
> +		fn = (unsigned int)id->driver_data;
> 
> -	*devfn = (unsigned int)id->driver_data;
> +	*devfn = fn;
>  	return 0;
>  }
> 
> --
> 2.35.1