diff mbox series

[v2,07/11] x86/amd: Detect preferred cores in amd_get_boost_ratio_numerator()

Message ID 20240903203701.2695040-8-superm1@kernel.org
State Superseded
Headers show
Series Adjustments for preferred core detection | expand

Commit Message

Mario Limonciello Sept. 3, 2024, 8:36 p.m. UTC 
From: Mario Limonciello <mario.limonciello@amd.com>

AMD systems that support preferred cores will use "166" as their
numerator for max frequency calculations instead of "255".

Add a function for detecting preferred cores by looking at the
highest perf value on all cores.

If preferred cores are enabled return 166 and if disabled the
value in the highest perf register. As the function will be called
multiple times, cache the values for the boost numerator and if
preferred cores will be enabled in global variables.

Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v1->v2:
 * Add a comment into amd_get_boost_ratio_numerator() as well
---
 arch/x86/kernel/acpi/cppc.c  | 93 ++++++++++++++++++++++++++++++++----
 drivers/cpufreq/amd-pstate.c | 34 +++++--------
 include/acpi/cppc_acpi.h     |  7 +++
 3 files changed, 103 insertions(+), 31 deletions(-)

Comments

kernel test robot Sept. 4, 2024, 9:18 p.m. UTC | #1 
Hi Mario,

kernel test robot noticed the following build errors:

[auto build test ERROR on rafael-pm/linux-next]
[also build test ERROR on rafael-pm/bleeding-edge tip/x86/core tip/master linus/master v6.11-rc6 next-20240904]
[cannot apply to tip/auto-latest]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Mario-Limonciello/x86-amd-Move-amd_get_highest_perf-from-amd-c-to-cppc-c/20240904-044140
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/20240903203701.2695040-8-superm1%40kernel.org
patch subject: [PATCH v2 07/11] x86/amd: Detect preferred cores in amd_get_boost_ratio_numerator()
config: i386-allmodconfig (https://download.01.org/0day-ci/archive/20240905/202409050432.AoAbkkyJ-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240905/202409050432.AoAbkkyJ-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409050432.AoAbkkyJ-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from drivers/cpufreq/amd-pstate.c:42:
>> include/acpi/cppc_acpi.h:242:19: error: static declaration of 'amd_get_highest_perf' follows non-static declaration
     242 | static inline int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf)
         |                   ^~~~~~~~~~~~~~~~~~~~
   include/acpi/cppc_acpi.h:141:12: note: previous declaration of 'amd_get_highest_perf' with type 'int(unsigned int,  u32 *)' {aka 'int(unsigned int,  unsigned int *)'}
     141 | extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
         |            ^~~~~~~~~~~~~~~~~~~~
>> include/acpi/cppc_acpi.h:246:19: error: static declaration of 'amd_get_boost_ratio_numerator' follows non-static declaration
     246 | static inline int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator)
         |                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/acpi/cppc_acpi.h:142:12: note: previous declaration of 'amd_get_boost_ratio_numerator' with type 'int(unsigned int,  u64 *)' {aka 'int(unsigned int,  long long unsigned int *)'}
     142 | extern int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator);
         |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/amd_get_highest_perf +242 include/acpi/cppc_acpi.h

337aadff8e4567 Ashwin Chaugule    2015-10-02  140  
7885bc49834406 Mario Limonciello  2024-09-03  141  extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
7885bc49834406 Mario Limonciello  2024-09-03  142  extern int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator);
8a02d99876362f Rafael J. Wysocki  2021-03-16  143  #ifdef CONFIG_ACPI_CPPC_LIB
1757d05f3112ac Xiongfeng Wang     2019-02-17  144  extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
0654cf05d17bc4 Rafael J. Wysocki  2021-09-04  145  extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);
12753d71e8c5c3 Meng Li            2024-01-19  146  extern int cppc_get_highest_perf(int cpunum, u64 *highest_perf);
337aadff8e4567 Ashwin Chaugule    2015-10-02  147  extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
337aadff8e4567 Ashwin Chaugule    2015-10-02  148  extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
fb0b00af04d083 Jinzhou Su         2021-12-24  149  extern int cppc_set_enable(int cpu, bool enable);
337aadff8e4567 Ashwin Chaugule    2015-10-02  150  extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
ae2df912d1a557 Jeremy Linton      2022-09-12  151  extern bool cppc_perf_ctrs_in_pcc(void);
50b813b147e9eb Vincent Guittot    2023-12-11  152  extern unsigned int cppc_perf_to_khz(struct cppc_perf_caps *caps, unsigned int perf);
50b813b147e9eb Vincent Guittot    2023-12-11  153  extern unsigned int cppc_khz_to_perf(struct cppc_perf_caps *caps, unsigned int freq);
a28b2bfc099c6b Ionela Voinescu    2020-12-14  154  extern bool acpi_cpc_valid(void);
3cc30dd00a580c Pierre Gondois     2022-05-18  155  extern bool cppc_allow_fast_switch(void);
a28b2bfc099c6b Ionela Voinescu    2020-12-14  156  extern int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data);
be8b88d7d98771 Prakash, Prashanth 2016-08-16  157  extern unsigned int cppc_get_transition_latency(int cpu);
ad3bc25a320742 Borislav Petkov    2018-12-05  158  extern bool cpc_ffh_supported(void);
8b356e536e69f3 Mario Limonciello  2022-07-05  159  extern bool cpc_supported_by_cpu(void);
ad3bc25a320742 Borislav Petkov    2018-12-05  160  extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val);
ad3bc25a320742 Borislav Petkov    2018-12-05  161  extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val);
7bc1fcd3990182 Perry Yuan         2023-01-31  162  extern int cppc_get_epp_perf(int cpunum, u64 *epp_perf);
7bc1fcd3990182 Perry Yuan         2023-01-31  163  extern int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable);
c984f5d5d45bd5 Wyes Karny         2023-03-07  164  extern int cppc_get_auto_sel_caps(int cpunum, struct cppc_perf_caps *perf_caps);
c984f5d5d45bd5 Wyes Karny         2023-03-07  165  extern int cppc_set_auto_sel(int cpu, bool enable);
cfa6630658f7de Mario Limonciello  2024-09-03  166  extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
402eea79aece78 Mario Limonciello  2024-09-03  167  extern int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator);
7885bc49834406 Mario Limonciello  2024-09-03  168  extern int amd_detect_prefcore(bool *detected);
8a02d99876362f Rafael J. Wysocki  2021-03-16  169  #else /* !CONFIG_ACPI_CPPC_LIB */
8a02d99876362f Rafael J. Wysocki  2021-03-16  170  static inline int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
8a02d99876362f Rafael J. Wysocki  2021-03-16  171  {
e224a868e488cf Mario Limonciello  2024-09-03  172  	return -EOPNOTSUPP;
8a02d99876362f Rafael J. Wysocki  2021-03-16  173  }
0654cf05d17bc4 Rafael J. Wysocki  2021-09-04  174  static inline int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
0654cf05d17bc4 Rafael J. Wysocki  2021-09-04  175  {
e224a868e488cf Mario Limonciello  2024-09-03  176  	return -EOPNOTSUPP;
0654cf05d17bc4 Rafael J. Wysocki  2021-09-04  177  }
12753d71e8c5c3 Meng Li            2024-01-19  178  static inline int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
12753d71e8c5c3 Meng Li            2024-01-19  179  {
e224a868e488cf Mario Limonciello  2024-09-03  180  	return -EOPNOTSUPP;
12753d71e8c5c3 Meng Li            2024-01-19  181  }
8a02d99876362f Rafael J. Wysocki  2021-03-16  182  static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
8a02d99876362f Rafael J. Wysocki  2021-03-16  183  {
e224a868e488cf Mario Limonciello  2024-09-03  184  	return -EOPNOTSUPP;
8a02d99876362f Rafael J. Wysocki  2021-03-16  185  }
8a02d99876362f Rafael J. Wysocki  2021-03-16  186  static inline int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
8a02d99876362f Rafael J. Wysocki  2021-03-16  187  {
e224a868e488cf Mario Limonciello  2024-09-03  188  	return -EOPNOTSUPP;
8a02d99876362f Rafael J. Wysocki  2021-03-16  189  }
fb0b00af04d083 Jinzhou Su         2021-12-24  190  static inline int cppc_set_enable(int cpu, bool enable)
fb0b00af04d083 Jinzhou Su         2021-12-24  191  {
e224a868e488cf Mario Limonciello  2024-09-03  192  	return -EOPNOTSUPP;
fb0b00af04d083 Jinzhou Su         2021-12-24  193  }
8a02d99876362f Rafael J. Wysocki  2021-03-16  194  static inline int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps)
8a02d99876362f Rafael J. Wysocki  2021-03-16  195  {
e224a868e488cf Mario Limonciello  2024-09-03  196  	return -EOPNOTSUPP;
8a02d99876362f Rafael J. Wysocki  2021-03-16  197  }
ae2df912d1a557 Jeremy Linton      2022-09-12  198  static inline bool cppc_perf_ctrs_in_pcc(void)
ae2df912d1a557 Jeremy Linton      2022-09-12  199  {
ae2df912d1a557 Jeremy Linton      2022-09-12  200  	return false;
ae2df912d1a557 Jeremy Linton      2022-09-12  201  }
8a02d99876362f Rafael J. Wysocki  2021-03-16  202  static inline bool acpi_cpc_valid(void)
8a02d99876362f Rafael J. Wysocki  2021-03-16  203  {
8a02d99876362f Rafael J. Wysocki  2021-03-16  204  	return false;
8a02d99876362f Rafael J. Wysocki  2021-03-16  205  }
3cc30dd00a580c Pierre Gondois     2022-05-18  206  static inline bool cppc_allow_fast_switch(void)
3cc30dd00a580c Pierre Gondois     2022-05-18  207  {
3cc30dd00a580c Pierre Gondois     2022-05-18  208  	return false;
3cc30dd00a580c Pierre Gondois     2022-05-18  209  }
8a02d99876362f Rafael J. Wysocki  2021-03-16  210  static inline unsigned int cppc_get_transition_latency(int cpu)
8a02d99876362f Rafael J. Wysocki  2021-03-16  211  {
8a02d99876362f Rafael J. Wysocki  2021-03-16  212  	return CPUFREQ_ETERNAL;
8a02d99876362f Rafael J. Wysocki  2021-03-16  213  }
8a02d99876362f Rafael J. Wysocki  2021-03-16  214  static inline bool cpc_ffh_supported(void)
8a02d99876362f Rafael J. Wysocki  2021-03-16  215  {
8a02d99876362f Rafael J. Wysocki  2021-03-16  216  	return false;
8a02d99876362f Rafael J. Wysocki  2021-03-16  217  }
8a02d99876362f Rafael J. Wysocki  2021-03-16  218  static inline int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
8a02d99876362f Rafael J. Wysocki  2021-03-16  219  {
e224a868e488cf Mario Limonciello  2024-09-03  220  	return -EOPNOTSUPP;
8a02d99876362f Rafael J. Wysocki  2021-03-16  221  }
8a02d99876362f Rafael J. Wysocki  2021-03-16  222  static inline int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
8a02d99876362f Rafael J. Wysocki  2021-03-16  223  {
e224a868e488cf Mario Limonciello  2024-09-03  224  	return -EOPNOTSUPP;
8a02d99876362f Rafael J. Wysocki  2021-03-16  225  }
7bc1fcd3990182 Perry Yuan         2023-01-31  226  static inline int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
7bc1fcd3990182 Perry Yuan         2023-01-31  227  {
e224a868e488cf Mario Limonciello  2024-09-03  228  	return -EOPNOTSUPP;
7bc1fcd3990182 Perry Yuan         2023-01-31  229  }
7bc1fcd3990182 Perry Yuan         2023-01-31  230  static inline int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
7bc1fcd3990182 Perry Yuan         2023-01-31  231  {
e224a868e488cf Mario Limonciello  2024-09-03  232  	return -EOPNOTSUPP;
7bc1fcd3990182 Perry Yuan         2023-01-31  233  }
c984f5d5d45bd5 Wyes Karny         2023-03-07  234  static inline int cppc_set_auto_sel(int cpu, bool enable)
c984f5d5d45bd5 Wyes Karny         2023-03-07  235  {
e224a868e488cf Mario Limonciello  2024-09-03  236  	return -EOPNOTSUPP;
c984f5d5d45bd5 Wyes Karny         2023-03-07  237  }
c984f5d5d45bd5 Wyes Karny         2023-03-07  238  static inline int cppc_get_auto_sel_caps(int cpunum, struct cppc_perf_caps *perf_caps)
c984f5d5d45bd5 Wyes Karny         2023-03-07  239  {
e224a868e488cf Mario Limonciello  2024-09-03  240  	return -EOPNOTSUPP;
c984f5d5d45bd5 Wyes Karny         2023-03-07  241  }
cfa6630658f7de Mario Limonciello  2024-09-03 @242  static inline int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf)
cfa6630658f7de Mario Limonciello  2024-09-03  243  {
cfa6630658f7de Mario Limonciello  2024-09-03  244  	return -ENODEV;
cfa6630658f7de Mario Limonciello  2024-09-03  245  }
402eea79aece78 Mario Limonciello  2024-09-03 @246  static inline int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator)
402eea79aece78 Mario Limonciello  2024-09-03  247  {
402eea79aece78 Mario Limonciello  2024-09-03  248  	return -EOPNOTSUPP;
402eea79aece78 Mario Limonciello  2024-09-03  249  }
7885bc49834406 Mario Limonciello  2024-09-03  250  static inline int amd_detect_prefcore(bool *detected)
7885bc49834406 Mario Limonciello  2024-09-03  251  {
7885bc49834406 Mario Limonciello  2024-09-03  252  	return -ENODEV;
7885bc49834406 Mario Limonciello  2024-09-03  253  }
8a02d99876362f Rafael J. Wysocki  2021-03-16  254  #endif /* !CONFIG_ACPI_CPPC_LIB */
337aadff8e4567 Ashwin Chaugule    2015-10-02  255
diff mbox series

Patch

diff --git a/arch/x86/kernel/acpi/cppc.c b/arch/x86/kernel/acpi/cppc.c
index a75dcb382c786..df367bc359308 100644
--- a/arch/x86/kernel/acpi/cppc.c
+++ b/arch/x86/kernel/acpi/cppc.c
@@ -9,6 +9,16 @@ 
 #include <asm/processor.h>
 #include <asm/topology.h>
 
+#define CPPC_HIGHEST_PERF_PREFCORE	166
+
+enum amd_pref_core {
+	AMD_PREF_CORE_UNKNOWN = 0,
+	AMD_PREF_CORE_SUPPORTED,
+	AMD_PREF_CORE_UNSUPPORTED,
+};
+static enum amd_pref_core amd_pref_core_detected;
+static u64 boost_numerator;
+
 /* Refer to drivers/acpi/cppc_acpi.c for the description of functions */
 
 bool cpc_supported_by_cpu(void)
@@ -146,6 +156,66 @@  int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf)
 }
 EXPORT_SYMBOL_GPL(amd_get_highest_perf);
 
+/**
+ * amd_detect_prefcore: Detect if CPUs in the system support preferred cores
+ * @detected: Output variable for the result of the detection.
+ *
+ * Determine whether CPUs in the system support preferred cores. On systems
+ * that support preferred cores, different highest perf values will be found
+ * on different cores. On other systems, the highest perf value will be the
+ * same on all cores.
+ *
+ * The result of the detection will be stored in the 'detected' parameter.
+ *
+ * Return: 0 for success, negative error code otherwise
+ */
+int amd_detect_prefcore(bool *detected)
+{
+	int cpu, count = 0;
+	u64 highest_perf[2] = {0};
+
+	if (WARN_ON(!detected))
+		return -EINVAL;
+
+	switch (amd_pref_core_detected) {
+	case AMD_PREF_CORE_SUPPORTED:
+		*detected = true;
+		return 0;
+	case AMD_PREF_CORE_UNSUPPORTED:
+		*detected = false;
+		return 0;
+	default:
+		break;
+	}
+
+	for_each_present_cpu(cpu) {
+		u32 tmp;
+		int ret;
+
+		ret = amd_get_highest_perf(cpu, &tmp);
+		if (ret)
+			return ret;
+
+		if (!count || (count == 1 && tmp != highest_perf[0]))
+			highest_perf[count++] = tmp;
+
+		if (count == 2)
+			break;
+	}
+
+	*detected = (count == 2);
+	boost_numerator = highest_perf[0];
+
+	amd_pref_core_detected = *detected ? AMD_PREF_CORE_SUPPORTED :
+					     AMD_PREF_CORE_UNSUPPORTED;
+
+	pr_debug("AMD CPPC preferred core is %ssupported (highest perf: 0x%llx)\n",
+		 *detected ? "" : "un", highest_perf[0]);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(amd_detect_prefcore);
+
 /**
  * amd_get_boost_ratio_numerator: Get the numerator to use for boost ratio calculation
  * @cpu: CPU to get numerator for.
@@ -155,24 +225,27 @@  EXPORT_SYMBOL_GPL(amd_get_highest_perf);
  * a CPU. On systems that support preferred cores, this will be a hardcoded
  * value. On other systems this will the highest performance register value.
  *
+ * If booting the system with amd-pstate enabled but preferred cores disabled then
+ * the correct boost numerator will be returned to match hardware capabilities
+ * even if the preferred cores scheduling hints are not enabled.
+ *
  * Return: 0 for success, negative error code otherwise.
  */
 int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator)
 {
-	struct cpuinfo_x86 *c = &boot_cpu_data;
+	bool prefcore;
+	int ret;
 
-	if (c->x86 == 0x17 && ((c->x86_model >= 0x30 && c->x86_model < 0x40) ||
-			       (c->x86_model >= 0x70 && c->x86_model < 0x80))) {
-		*numerator = 166;
-		return 0;
-	}
+	ret = amd_detect_prefcore(&prefcore);
+	if (ret)
+		return ret;
 
-	if (c->x86 == 0x19 && ((c->x86_model >= 0x20 && c->x86_model < 0x30) ||
-			       (c->x86_model >= 0x40 && c->x86_model < 0x70))) {
-		*numerator = 166;
+	/* without preferred cores, return the highest perf register value */
+	if (!prefcore) {
+		*numerator = boost_numerator;
 		return 0;
 	}
-	*numerator = 255;
+	*numerator = CPPC_HIGHEST_PERF_PREFCORE;
 
 	return 0;
 }
diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 44df6ef66b5fa..c29cdf2d3882c 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -807,32 +807,18 @@  static DECLARE_WORK(sched_prefcore_work, amd_pstste_sched_prefcore_workfn);
 
 static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata)
 {
-	int ret, prio;
-	u32 highest_perf;
-
-	ret = amd_get_highest_perf(cpudata->cpu, &highest_perf);
-	if (ret)
+	/* user disabled or not detected */
+	if (!amd_pstate_prefcore)
 		return;
 
 	cpudata->hw_prefcore = true;
-	/* check if CPPC preferred core feature is enabled*/
-	if (highest_perf < CPPC_MAX_PERF)
-		prio = (int)highest_perf;
-	else {
-		pr_debug("AMD CPPC preferred core is unsupported!\n");
-		cpudata->hw_prefcore = false;
-		return;
-	}
-
-	if (!amd_pstate_prefcore)
-		return;
 
 	/*
 	 * The priorities can be set regardless of whether or not
 	 * sched_set_itmt_support(true) has been called and it is valid to
 	 * update them at any time after it has been called.
 	 */
-	sched_set_itmt_core_prio(prio, cpudata->cpu);
+	sched_set_itmt_core_prio((int)READ_ONCE(cpudata->highest_perf), cpudata->cpu);
 
 	schedule_work(&sched_prefcore_work);
 }
@@ -998,12 +984,12 @@  static int amd_pstate_cpu_init(struct cpufreq_policy *policy)
 
 	cpudata->cpu = policy->cpu;
 
-	amd_pstate_init_prefcore(cpudata);
-
 	ret = amd_pstate_init_perf(cpudata);
 	if (ret)
 		goto free_cpudata1;
 
+	amd_pstate_init_prefcore(cpudata);
+
 	ret = amd_pstate_init_freq(cpudata);
 	if (ret)
 		goto free_cpudata1;
@@ -1453,12 +1439,12 @@  static int amd_pstate_epp_cpu_init(struct cpufreq_policy *policy)
 	cpudata->cpu = policy->cpu;
 	cpudata->epp_policy = 0;
 
-	amd_pstate_init_prefcore(cpudata);
-
 	ret = amd_pstate_init_perf(cpudata);
 	if (ret)
 		goto free_cpudata1;
 
+	amd_pstate_init_prefcore(cpudata);
+
 	ret = amd_pstate_init_freq(cpudata);
 	if (ret)
 		goto free_cpudata1;
@@ -1920,6 +1906,12 @@  static int __init amd_pstate_init(void)
 		static_call_update(amd_pstate_update_perf, cppc_update_perf);
 	}
 
+	if (amd_pstate_prefcore) {
+		ret = amd_detect_prefcore(&amd_pstate_prefcore);
+		if (ret)
+			return ret;
+	}
+
 	/* enable amd pstate feature */
 	ret = amd_pstate_enable(true);
 	if (ret) {
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index f7c7abf2a95e9..67325a9294ba1 100644
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -136,6 +136,8 @@  struct cppc_cpudata {
 	cpumask_var_t shared_cpu_map;
 };
 
+extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
+extern int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator);
 #ifdef CONFIG_ACPI_CPPC_LIB
 extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
 extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);
@@ -161,6 +163,7 @@  extern int cppc_get_auto_sel_caps(int cpunum, struct cppc_perf_caps *perf_caps);
 extern int cppc_set_auto_sel(int cpu, bool enable);
 extern int amd_get_highest_perf(unsigned int cpu, u32 *highest_perf);
 extern int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator);
+extern int amd_detect_prefcore(bool *detected);
 #else /* !CONFIG_ACPI_CPPC_LIB */
 static inline int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
 {
@@ -242,6 +245,10 @@  static inline int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator
 {
 	return -EOPNOTSUPP;
 }
+static inline int amd_detect_prefcore(bool *detected)
+{
+	return -ENODEV;
+}
 #endif /* !CONFIG_ACPI_CPPC_LIB */
 
 #endif /* _CPPC_ACPI_H*/