[v4,6/6] cpufreq:amd-pstate: add quirk for the pstate CPPC capabilities missing

  Add quirks table to get CPPC capabilities issue fixed by providing
correct perf or frequency values while driver loading.

If CPPC capabilities are not defined in the ACPI tables or wrongly
defined by platform firmware, it needs to use quick to get those
issues fixed with correct workaround values to make pstate driver
can be loaded even though there are CPPC capabilities errors.

The workaround will match the broken BIOS which lack of CPPC capabilities
nominal_freq and lowest_freq definition in the ACPI table.

$ cat /sys/devices/system/cpu/cpu0/acpi_cppc/lowest_freq
0
$ cat /sys/devices/system/cpu/cpu0/acpi_cppc/nominal_freq
0

Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 59 ++++++++++++++++++++++++++++++++++--
 include/linux/amd-pstate.h   |  6 ++++
 2 files changed, 63 insertions(+), 2 deletions(-)
  

On 2/5/2024 22:33, Perry Yuan wrote:
> Add quirks table to get CPPC capabilities issue fixed by providing
> correct perf or frequency values while driver loading.
> 
> If CPPC capabilities are not defined in the ACPI tables or wrongly
> defined by platform firmware, it needs to use quick to get those
s,quick,a quirk,
> issues fixed with correct workaround values to make pstate driver
> can be loaded even though there are CPPC capabilities errors.
> 
> The workaround will match the broken BIOS which lack of CPPC capabilities
> nominal_freq and lowest_freq definition in the ACPI table.
> 
> $ cat /sys/devices/system/cpu/cpu0/acpi_cppc/lowest_freq
> 0
> $ cat /sys/devices/system/cpu/cpu0/acpi_cppc/nominal_freq
> 0
> 
> Signed-off-by: Perry Yuan <perry.yuan@amd.com>
> ---
>   drivers/cpufreq/amd-pstate.c | 59 ++++++++++++++++++++++++++++++++++--
>   include/linux/amd-pstate.h   |  6 ++++
>   2 files changed, 63 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 77effc3caf6c..874d8b663790 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -67,6 +67,7 @@ static struct cpufreq_driver amd_pstate_epp_driver;
>   static int cppc_state = AMD_PSTATE_UNDEFINED;
>   static bool cppc_enabled;
>   static bool amd_pstate_prefcore = true;
> +static struct quirk_entry *quirks;
>   
>   /*
>    * AMD Energy Preference Performance (EPP)
> @@ -111,6 +112,43 @@ static unsigned int epp_values[] = {
>   
>   typedef int (*cppc_mode_transition_fn)(int);
>   
> +static struct quirk_entry quirk_amd_7k62 = {
> +	.nominal_freq = 2600,
> +	.lowest_freq = 550,
> +};
> +
> +static int __init dmi_matched_7k62_bios_bug(const struct dmi_system_id *dmi)
> +{
> +	/**
> +	 * match the broken bios for family 17h, model 31h processor
> +	 * broken BIOS lack of nominal_freq and lowest_freq capabilities
> +	 * definition in ACPI tables
> +	 */
> +	if (boot_cpu_data.x86 == 0x17 && boot_cpu_data.x86_model == 0x31 &&
> +			boot_cpu_has(X86_FEATURE_ZEN2)) {

I think you should use one or the other (17/31) or (X86_FEATURE_ZEN2).

> +		quirks = dmi->driver_data;
> +		pr_info("hardware type %s found\n", dmi->ident);

I think a better message explains what is happening.  For example:
"Overriding nominal and lowest frequencies for %s\n"

> +		return 1;
> +	}
> +
> +

Only need one newline needed here.

> +	return 0;
> +}
> +
> +static const struct dmi_system_id amd_pstate_quirks_table[] __initconst = {
> +	{
> +		.callback = dmi_matched_7k62_bios_bug,
> +		.ident = "AMD EPYC 7K62",
> +		.matches = {
> +			DMI_MATCH(DMI_BIOS_VERSION, "5.14"),
> +			DMI_MATCH(DMI_BIOS_RELEASE, "12/12/2019"),
> +		},
> +		.driver_data = &quirk_amd_7k62,
> +	},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(dmi, amd_pstate_quirks_table);
> +
>   static inline int get_mode_idx_from_str(const char *str, size_t size)
>   {
>   	int i;
> @@ -600,13 +638,19 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
>   static int amd_get_min_freq(struct amd_cpudata *cpudata)
>   {
>   	struct cppc_perf_caps cppc_perf;
> +	u32 lowest_freq;
>   
>   	int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
>   	if (ret)
>   		return ret;
>   
> +	if (quirks && quirks->lowest_freq)
> +		lowest_freq = quirks->lowest_freq;
> +	else
> +		lowest_freq = cppc_perf.lowest_freq;
> +
>   	/* Switch to khz */
> -	return cppc_perf.lowest_freq * 1000;
> +	return lowest_freq * 1000;
>   }
>   
>   static int amd_get_max_freq(struct amd_cpudata *cpudata)
> @@ -635,12 +679,18 @@ static int amd_get_max_freq(struct amd_cpudata *cpudata)
>   static int amd_get_nominal_freq(struct amd_cpudata *cpudata)
>   {
>   	struct cppc_perf_caps cppc_perf;
> +	u32 nominal_freq;
>   
>   	int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
>   	if (ret)
>   		return ret;
>   
> -	return cppc_perf.nominal_freq;
> +	if (quirks && quirks->nominal_freq)
> +		nominal_freq = quirks->nominal_freq;
> +	else
> +		nominal_freq = cppc_perf.nominal_freq;
> +
> +	return nominal_freq;
>   }
>   
>   static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
> @@ -1672,6 +1722,11 @@ static int __init amd_pstate_init(void)
>   	if (cpufreq_get_current_driver())
>   		return -EEXIST;
>   
> +	quirks = NULL;
> +
> +	/* check if this machine need CPPC quirks */
> +	dmi_check_system(amd_pstate_quirks_table);
> +
>   	switch (cppc_state) {
>   	case AMD_PSTATE_UNDEFINED:
>   		/* Disable on the following configs by default:
> diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> index d21838835abd..7b2cbb892fd9 100644
> --- a/include/linux/amd-pstate.h
> +++ b/include/linux/amd-pstate.h
> @@ -124,4 +124,10 @@ static const char * const amd_pstate_mode_string[] = {
>   	[AMD_PSTATE_GUIDED]      = "guided",
>   	NULL,
>   };
> +
> +struct quirk_entry {
> +	u32 nominal_freq;
> +	u32 lowest_freq;
> +};
> +
>   #endif /* _LINUX_AMD_PSTATE_H */
  

[AMD Official Use Only - General]

Hi Mario,

> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@amd.com>
> Sent: Tuesday, February 6, 2024 11:46 PM
> To: Yuan, Perry <Perry.Yuan@amd.com>; rafael.j.wysocki@intel.com;
> viresh.kumar@linaro.org; Huang, Ray <Ray.Huang@amd.com>; Shenoy,
> Gautham Ranjal <gautham.shenoy@amd.com>; Petkov, Borislav
> <Borislav.Petkov@amd.com>
> Cc: Deucher, Alexander <Alexander.Deucher@amd.com>; Huang, Shimmer
> <Shimmer.Huang@amd.com>; Du, Xiaojian <Xiaojian.Du@amd.com>; Meng,
> Li (Jassmine) <Li.Meng@amd.com>; linux-pm@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH v4 6/6] cpufreq:amd-pstate: add quirk for the pstate
> CPPC capabilities missing
>
> On 2/5/2024 22:33, Perry Yuan wrote:
> > Add quirks table to get CPPC capabilities issue fixed by providing
> > correct perf or frequency values while driver loading.
> >
> > If CPPC capabilities are not defined in the ACPI tables or wrongly
> > defined by platform firmware, it needs to use quick to get those
> s,quick,a quirk,
> > issues fixed with correct workaround values to make pstate driver can
> > be loaded even though there are CPPC capabilities errors.
> >
> > The workaround will match the broken BIOS which lack of CPPC
> > capabilities nominal_freq and lowest_freq definition in the ACPI table.
> >
> > $ cat /sys/devices/system/cpu/cpu0/acpi_cppc/lowest_freq
> > 0
> > $ cat /sys/devices/system/cpu/cpu0/acpi_cppc/nominal_freq
> > 0
> >
> > Signed-off-by: Perry Yuan <perry.yuan@amd.com>
> > ---
> >   drivers/cpufreq/amd-pstate.c | 59
> ++++++++++++++++++++++++++++++++++--
> >   include/linux/amd-pstate.h   |  6 ++++
> >   2 files changed, 63 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c
> > b/drivers/cpufreq/amd-pstate.c index 77effc3caf6c..874d8b663790 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -67,6 +67,7 @@ static struct cpufreq_driver amd_pstate_epp_driver;
> >   static int cppc_state = AMD_PSTATE_UNDEFINED;
> >   static bool cppc_enabled;
> >   static bool amd_pstate_prefcore = true;
> > +static struct quirk_entry *quirks;
> >
> >   /*
> >    * AMD Energy Preference Performance (EPP) @@ -111,6 +112,43 @@
> > static unsigned int epp_values[] = {
> >
> >   typedef int (*cppc_mode_transition_fn)(int);
> >
> > +static struct quirk_entry quirk_amd_7k62 = {
> > +   .nominal_freq = 2600,
> > +   .lowest_freq = 550,
> > +};
> > +
> > +static int __init dmi_matched_7k62_bios_bug(const struct
> > +dmi_system_id *dmi) {
> > +   /**
> > +    * match the broken bios for family 17h, model 31h processor
> > +    * broken BIOS lack of nominal_freq and lowest_freq capabilities
> > +    * definition in ACPI tables
> > +    */
> > +   if (boot_cpu_data.x86 == 0x17 && boot_cpu_data.x86_model ==
> 0x31 &&
> > +                   boot_cpu_has(X86_FEATURE_ZEN2)) {
>
> I think you should use one or the other (17/31) or (X86_FEATURE_ZEN2).

Looks like it makes sense to match ZEN2 flag and specific BIOS version.  That will cover the broken BIOS and CPU.


>
> > +           quirks = dmi->driver_data;
> > +           pr_info("hardware type %s found\n", dmi->ident);
>
> I think a better message explains what is happening.  For example:
> "Overriding nominal and lowest frequencies for %s\n"

Made suggestions to v5.

>
> > +           return 1;
> > +   }
> > +
> > +
>
> Only need one newline needed here.

Fixed in V5.

Thanks for the review comments!

Perry.

>
> > +   return 0;
> > +}
> > +
> > +static const struct dmi_system_id amd_pstate_quirks_table[] __initconst
> = {
> > +   {
> > +           .callback = dmi_matched_7k62_bios_bug,
> > +           .ident = "AMD EPYC 7K62",
> > +           .matches = {
> > +                   DMI_MATCH(DMI_BIOS_VERSION, "5.14"),
> > +                   DMI_MATCH(DMI_BIOS_RELEASE, "12/12/2019"),
> > +           },
> > +           .driver_data = &quirk_amd_7k62,
> > +   },
> > +   {}
> > +};
> > +MODULE_DEVICE_TABLE(dmi, amd_pstate_quirks_table);
> > +
> >   static inline int get_mode_idx_from_str(const char *str, size_t size)
> >   {
> >     int i;
> > @@ -600,13 +638,19 @@ static void amd_pstate_adjust_perf(unsigned int
> cpu,
> >   static int amd_get_min_freq(struct amd_cpudata *cpudata)
> >   {
> >     struct cppc_perf_caps cppc_perf;
> > +   u32 lowest_freq;
> >
> >     int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
> >     if (ret)
> >             return ret;
> >
> > +   if (quirks && quirks->lowest_freq)
> > +           lowest_freq = quirks->lowest_freq;
> > +   else
> > +           lowest_freq = cppc_perf.lowest_freq;
> > +
> >     /* Switch to khz */
> > -   return cppc_perf.lowest_freq * 1000;
> > +   return lowest_freq * 1000;
> >   }
> >
> >   static int amd_get_max_freq(struct amd_cpudata *cpudata) @@ -635,12
> > +679,18 @@ static int amd_get_max_freq(struct amd_cpudata *cpudata)
> >   static int amd_get_nominal_freq(struct amd_cpudata *cpudata)
> >   {
> >     struct cppc_perf_caps cppc_perf;
> > +   u32 nominal_freq;
> >
> >     int ret = cppc_get_perf_caps(cpudata->cpu, &cppc_perf);
> >     if (ret)
> >             return ret;
> >
> > -   return cppc_perf.nominal_freq;
> > +   if (quirks && quirks->nominal_freq)
> > +           nominal_freq = quirks->nominal_freq;
> > +   else
> > +           nominal_freq = cppc_perf.nominal_freq;
> > +
> > +   return nominal_freq;
> >   }
> >
> >   static int amd_get_lowest_nonlinear_freq(struct amd_cpudata
> > *cpudata) @@ -1672,6 +1722,11 @@ static int __init amd_pstate_init(void)
> >     if (cpufreq_get_current_driver())
> >             return -EEXIST;
> >
> > +   quirks = NULL;
> > +
> > +   /* check if this machine need CPPC quirks */
> > +   dmi_check_system(amd_pstate_quirks_table);
> > +
> >     switch (cppc_state) {
> >     case AMD_PSTATE_UNDEFINED:
> >             /* Disable on the following configs by default:
> > diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
> > index d21838835abd..7b2cbb892fd9 100644
> > --- a/include/linux/amd-pstate.h
> > +++ b/include/linux/amd-pstate.h
> > @@ -124,4 +124,10 @@ static const char * const
> amd_pstate_mode_string[] = {
> >     [AMD_PSTATE_GUIDED]      = "guided",
> >     NULL,
> >   };
> > +
> > +struct quirk_entry {
> > +   u32 nominal_freq;
> > +   u32 lowest_freq;
> > +};
> > +
> >   #endif /* _LINUX_AMD_PSTATE_H */