[PATCH v4 0/6] AMD Pstate Fixes And Enhancements

[PATCH v4 0/6] AMD Pstate Fixes And Enhancements

[Perry Yuan]

*** BLURB HERE ***
The patch series adds some fixes and enhancements to the AMD pstate
driver.
It enables CPPC v2 for certain processors in the family 17H, as
requested
by TR40 processor users who expect improved performance and lower system
temperature.

Additionally, it fixes the initialization of nominal_freq for each
cpudata
and changes latency and delay values to be read from platform firmware
firstly
for more accurate timing.

A new quirk is also added for legacy processors that lack CPPC
capabilities which caused the pstate driver to fail loading.

I would greatly appreciate any feedbacks.

Thank you!

Changes from v3:
 * change quirk matching broken BIOS with family/model ID and Zen2
   flag to fix the CPPC definition issue
 * fix typo in quirk

Changes from v2:
 * change quirk matching to BIOS version and release (Mario)
 * pick up RB flag from Mario

Changes from v1:
 * pick up the RB flags from Mario
 * address review comment of patch #6 for amd_get_nominal_freq()
 * rebased the series to linux-pm/bleeding-edge v6.8.0-rc2
 * update debug log for patch #5 as Mario suggested.
 * fix some typos and format problems
 * tested on 7950X platform


V1: https://lore.kernel.org/lkml/63c2b3d7-083a-4daa-ba40-629b3223a92d@mailbox.org/
V2: https://lore.kernel.org/all/cover.1706863981.git.perry.yuan@amd.com/
v3: https://lore.kernel.org/lkml/cover.1707016927.git.perry.yuan@amd.com/

Perry Yuan (6):
  ACPI: CPPC: enable AMD CPPC V2 support for family 17h processors
  cpufreq:amd-pstate: fix the nominal freq value set
  cpufreq:amd-pstate: initialize nominal_freq of each cpudata
  cpufreq:amd-pstate: get pstate transition delay and latency value from
    ACPI tables
  cppc_acpi: print error message if CPPC is unsupported
  cpufreq:amd-pstate: add quirk for the pstate CPPC capabilities missing

 arch/x86/kernel/acpi/cppc.c  |   2 +-
 drivers/acpi/cppc_acpi.c     |   4 +-
 drivers/cpufreq/amd-pstate.c | 118 ++++++++++++++++++++++++++++++-----
 include/linux/amd-pstate.h   |   6 ++
 4 files changed, 111 insertions(+), 19 deletions(-)

-- 
2.34.1

[PATCH v4 1/6] ACPI: CPPC: enable AMD CPPC V2 support for family 17h processors

[Perry Yuan]

As there are some AMD processors which only support CPPC V2 firmware and
BIOS implementation, the amd_pstate driver will be failed to load when
system booting with below kernel warning message:

[    0.477523] amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled

To make the amd_pstate driver can be loaded on those TR40 processors, it
needs to match x86_model from 0x30 to 0x7F for family 17H.
With the change, the system can load amd_pstate driver as expected.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reported-by: Gino Badouri <badouri.g@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218171
Fixes: fbd74d1689 ("ACPI: CPPC: Fix enabling CPPC on AMD systems with shared memory")
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
 arch/x86/kernel/acpi/cppc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c
index 8d8752b44f11..ff8f25faca3d 100644
--- a/arch/x86/kernel/acpi/cppc.c
+++ b/arch/x86/kernel/acpi/cppc.c
@@ -20,7 +20,7 @@ bool cpc_supported_by_cpu(void)
 		    (boot_cpu_data.x86_model >= 0x20 && boot_cpu_data.x86_model <= 0x2f)))
 			return true;
 		else if (boot_cpu_data.x86 == 0x17 &&
-			 boot_cpu_data.x86_model >= 0x70 && boot_cpu_data.x86_model <= 0x7f)
+			 boot_cpu_data.x86_model >= 0x30 && boot_cpu_data.x86_model <= 0x7f)
 			return true;
 		return boot_cpu_has(X86_FEATURE_CPPC);
 	}
-- 
2.34.1

[PATCH v4 2/6] cpufreq:amd-pstate: fix the nominal freq value set

[Perry Yuan]

Address an untested error where the nominal_freq was returned in KHz
instead of the correct MHz units, this oversight led to a wrong
nominal_freq set and resued, it will cause the max frequency of core to
be initialized with a wrong frequency value.

Cc: stable@vger.kernel.org
Fixes: ec437d71db7 ("cpufreq: amd-pstate: Introduce a new AMD P-State driver to support future processors")
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 08e112444c27..ac7faa98a450 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -640,8 +640,7 @@ static int amd_get_nominal_freq(struct amd_cpudata *cpudata)
 	if (ret)
 		return ret;
 
-	/* Switch to khz */
-	return cppc_perf.nominal_freq * 1000;
+	return cppc_perf.nominal_freq;
 }
 
 static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
-- 
2.34.1

[PATCH v4 3/6] cpufreq:amd-pstate: initialize nominal_freq of each cpudata

[Perry Yuan]

Optimizes the process of retrieving the nominal frequency by utilizing
'cpudata->nominal_freq' instead of repeatedly accessing the cppc_acpi interface.

To enhance efficiency and reduce the CPU load, shifted to using
'cpudata->nominal_freq'. It allows for the nominal frequency to be accessed
directly from the cached data in 'cpudata' of each CPU.
It will also slightly reduce the frequency change latency while using pstate
driver passive mode.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index ac7faa98a450..ea8681ea3bad 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -619,7 +619,7 @@ static int amd_get_max_freq(struct amd_cpudata *cpudata)
 	if (ret)
 		return ret;
 
-	nominal_freq = cppc_perf.nominal_freq;
+	nominal_freq = READ_ONCE(cpudata->nominal_freq);
 	nominal_perf = READ_ONCE(cpudata->nominal_perf);
 	max_perf = READ_ONCE(cpudata->highest_perf);
 
@@ -654,7 +654,7 @@ static int amd_get_lowest_nonlinear_freq(struct amd_cpudata *cpudata)
 	if (ret)
 		return ret;
 
-	nominal_freq = cppc_perf.nominal_freq;
+	nominal_freq = READ_ONCE(cpudata->nominal_freq);
 	nominal_perf = READ_ONCE(cpudata->nominal_perf);
 
 	lowest_nonlinear_perf = cppc_perf.lowest_nonlinear_perf;
@@ -848,13 +848,14 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 		goto free_cpudata1;
 
 	min_freq = amd_get_min_freq(cpudata);
-	max_freq = amd_get_max_freq(cpudata);
 	nominal_freq = amd_get_nominal_freq(cpudata);
+	cpudata->nominal_freq = nominal_freq;
+	max_freq = amd_get_max_freq(cpudata);
 	lowest_nonlinear_freq = amd_get_lowest_nonlinear_freq(cpudata);
 
-	if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
-		dev_err(dev, "min_freq(%d) or max_freq(%d) value is incorrect\n",
-			min_freq, max_freq);
+	if (min_freq < 0 || max_freq < 0 || min_freq > max_freq || nominal_freq == 0) {
+		dev_err(dev, "min_freq(%d) or max_freq(%d) or nominal_freq(%d) is incorrect\n",
+			min_freq, max_freq, nominal_freq);
 		ret = -EINVAL;
 		goto free_cpudata1;
 	}
@@ -893,7 +894,6 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 	cpudata->min_freq = min_freq;
 	cpudata->max_limit_freq = max_freq;
 	cpudata->min_limit_freq = min_freq;
-	cpudata->nominal_freq = nominal_freq;
 	cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
 
 	policy->driver_data = cpudata;
@@ -1310,12 +1310,13 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 		goto free_cpudata1;
 
 	min_freq = amd_get_min_freq(cpudata);
-	max_freq = amd_get_max_freq(cpudata);
 	nominal_freq = amd_get_nominal_freq(cpudata);
+	cpudata->nominal_freq = nominal_freq;
+	max_freq = amd_get_max_freq(cpudata);
 	lowest_nonlinear_freq = amd_get_lowest_nonlinear_freq(cpudata);
-	if (min_freq < 0 || max_freq < 0 || min_freq > max_freq) {
-		dev_err(dev, "min_freq(%d) or max_freq(%d) value is incorrect\n",
-				min_freq, max_freq);
+	if (min_freq < 0 || max_freq < 0 || min_freq > max_freq || nominal_freq == 0) {
+		dev_err(dev, "min_freq(%d) or max_freq(%d) or nominal_freq(%d) is incorrect\n",
+				min_freq, max_freq, nominal_freq);
 		ret = -EINVAL;
 		goto free_cpudata1;
 	}
@@ -1328,7 +1329,6 @@ static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 	/* Initial processor data capability frequencies */
 	cpudata->max_freq = max_freq;
 	cpudata->min_freq = min_freq;
-	cpudata->nominal_freq = nominal_freq;
 	cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
 
 	policy->driver_data = cpudata;
-- 
2.34.1

[PATCH v4 4/6] cpufreq:amd-pstate: get pstate transition delay and latency value from ACPI tables

[Perry Yuan]

make pstate driver initially retrieve the P-state transition delay and latency
values from the BIOS ACPI tables which has more reasonable delay and latency
values according to the platform design and requirements.

Previously there values were hardcoded at specific value which may
have conflicted with platform and it might not reflect the most accurate or
optimized setting for the processor.

[054h 0084   8]                Preserve Mask : FFFFFFFF00000000
[05Ch 0092   8]                   Write Mask : 0000000000000001
[064h 0100   4]              Command Latency : 00000FA0
[068h 0104   4]          Maximum Access Rate : 0000EA60
[06Ch 0108   2]      Minimum Turnaround Time : 0000

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
 drivers/cpufreq/amd-pstate.c | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index ea8681ea3bad..77effc3caf6c 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -820,6 +820,36 @@ static void amd_pstate_update_limits(unsigned int cpu)
 	mutex_unlock(&amd_pstate_driver_lock);
 }
 
+/**
+ * Get pstate transition delay time from ACPI tables that firmware set
+ * instead of using hardcode value directly.
+ */
+static u32 amd_pstate_get_transition_delay_us(unsigned int cpu)
+{
+	u32 transition_delay_ns;
+
+	transition_delay_ns = cppc_get_transition_latency(cpu);
+	if (transition_delay_ns == CPUFREQ_ETERNAL)
+		return AMD_PSTATE_TRANSITION_DELAY;
+
+	return transition_delay_ns / NSEC_PER_USEC;
+}
+
+/**
+ * Get pstate transition latency value from ACPI tables that firmware set
+ * instead of using hardcode value directly.
+ */
+static u32 amd_pstate_get_transition_latency(unsigned int cpu)
+{
+	u32 transition_latency;
+
+	transition_latency = cppc_get_transition_latency(cpu);
+	if (transition_latency  == CPUFREQ_ETERNAL)
+		return AMD_PSTATE_TRANSITION_LATENCY;
+
+	return transition_latency;
+}
+
 static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 {
 	int min_freq, max_freq, nominal_freq, lowest_nonlinear_freq, ret;
@@ -860,8 +890,8 @@ static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 		goto free_cpudata1;
 	}
 
-	policy->cpuinfo.transition_latency = AMD_PSTATE_TRANSITION_LATENCY;
-	policy->transition_delay_us = AMD_PSTATE_TRANSITION_DELAY;
+	policy->cpuinfo.transition_latency = amd_pstate_get_transition_latency(policy->cpu);
+	policy->transition_delay_us = amd_pstate_get_transition_delay_us(policy->cpu);
 
 	policy->min = min_freq;
 	policy->max = max_freq;
-- 
2.34.1

[PATCH v4 5/6] cppc_acpi: print error message if CPPC is unsupported

[Perry Yuan]

to be more clear what is wrong with CPPC when pstate driver failed to
load which has dependency on the CPPC capabilities.

Add one more debug message to notify user if CPPC is not supported by
the CPU, then it will be easy to find out what need to fix for pstate
driver loading issue.

[    0.477523] amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled

Above message is not clear enough to verify whether CPPC is not supported.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
---
 drivers/acpi/cppc_acpi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index a50e70abdf19..e23a84f4a50a 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -679,8 +679,10 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 
 	if (!osc_sb_cppc2_support_acked) {
 		pr_debug("CPPC v2 _OSC not acked\n");
-		if (!cpc_supported_by_cpu())
+		if (!cpc_supported_by_cpu()) {
+			pr_debug("CPPC is not supported by the CPU\n");
 			return -ENODEV;
+		}
 	}
 
 	/* Parse the ACPI _CPC table for this CPU. */
-- 
2.34.1

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

[Perry Yuan]

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(-)

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)) {
+		quirks = dmi->driver_data;
+		pr_info("hardware type %s found\n", dmi->ident);
+		return 1;
+	}
+
+
+	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 */
-- 
2.34.1

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

[Mario Limonciello]

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 */

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

[Yuan, Perry]

[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 */