Message-ID: <20260129183646.558866-6-sathyanarayanan.kuppuswamy@linux.intel.com>
Date: Thu, 29 Jan 2026 10:36:42 -0800
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
To: "Rafael J . Wysocki" <rafael@...nel.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: Zhang Rui <rui.zhang@...el.com>,
	Lukasz Luba <lukasz.luba@....com>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v1 5/9] powercap: intel_rapl: Allow interface drivers to configure rapl_defaults

RAPL default settings vary across different RAPL interfaces (MSR, TPMI,
MMIO). Currently, these defaults are stored in the common RAPL driver,
which requires interface-specific handling logic and makes the common
layer unnecessarily complex. There is no strong reason for the common
code to own these defaults, since they are inherently
interface-specific.

To prepare for moving default configuration into the individual
interface drivers,

1. Move struct rapl_defaults into a shared header so that interface
   drivers can directly populate their own default settings.
2. Change the @defaults field in struct rapl_if_priv from void * to
   const struct rapl_defaults * to improve type safety and readability
   and update the common driver to use the typed defaults structure.
3. Update all internal getter functions and local pointers to use
   const struct rapl_defaults * to maintain const-correctness.
4. Rename and export the common helper functions (check_unit,
   set_floor_freq, compute_time_window) so interface drivers may
   reuse or override them as appropriate.

No functional changes. This is a preparatory refactoring to allow
interface drivers to supply their own RAPL default settings.

Co-developed-by: Zhang Rui <rui.zhang@...el.com>
Signed-off-by: Zhang Rui <rui.zhang@...el.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
---
 drivers/powercap/intel_rapl_common.c | 64 ++++++++++++----------------
 include/linux/intel_rapl.h           | 17 +++++++-
 2 files changed, 43 insertions(+), 38 deletions(-)

diff --git a/drivers/powercap/intel_rapl_common.c b/drivers/powercap/intel_rapl_common.c
index 8f9d504fb64c..b60d8fd6cc82 100644
--- a/drivers/powercap/intel_rapl_common.c
+++ b/drivers/powercap/intel_rapl_common.c
@@ -221,20 +221,10 @@ static int get_pl_prim(struct rapl_domain *rd, int pl, enum pl_prims prim)
 #define power_zone_to_rapl_domain(_zone) \
 	container_of(_zone, struct rapl_domain, power_zone)
 
-struct rapl_defaults {
-	u8 floor_freq_reg_addr;
-	int (*check_unit)(struct rapl_domain *rd);
-	void (*set_floor_freq)(struct rapl_domain *rd, bool mode);
-	u64 (*compute_time_window)(struct rapl_domain *rd, u64 val,
-				    bool to_raw);
-	unsigned int dram_domain_energy_unit;
-	unsigned int psys_domain_energy_unit;
-	bool spr_psys_bits;
-};
-static struct rapl_defaults *defaults_msr;
+static const struct rapl_defaults *defaults_msr;
 static const struct rapl_defaults defaults_tpmi;
 
-static struct rapl_defaults *get_defaults(struct rapl_package *rp)
+static const struct rapl_defaults *get_defaults(struct rapl_package *rp)
 {
 	return rp->priv->defaults;
 }
@@ -351,7 +341,7 @@ static int find_nr_power_limit(struct rapl_domain *rd)
 static int set_domain_enable(struct powercap_zone *power_zone, bool mode)
 {
 	struct rapl_domain *rd = power_zone_to_rapl_domain(power_zone);
-	struct rapl_defaults *defaults = get_defaults(rd->rp);
+	const struct rapl_defaults *defaults = get_defaults(rd->rp);
 	u64 val;
 	int ret;
 
@@ -640,7 +630,7 @@ static u64 rapl_unit_xlate(struct rapl_domain *rd, enum unit_type type,
 			   u64 value, int to_raw)
 {
 	u64 units = 1;
-	struct rapl_defaults *defaults = get_defaults(rd->rp);
+	const struct rapl_defaults *defaults = get_defaults(rd->rp);
 	u64 scale = 1;
 
 	switch (type) {
@@ -785,11 +775,11 @@ static int rapl_config(struct rapl_package *rp)
 	/* MMIO I/F shares the same register layout as MSR registers */
 	case RAPL_IF_MMIO:
 	case RAPL_IF_MSR:
-		rp->priv->defaults = (void *)defaults_msr;
+		rp->priv->defaults = defaults_msr;
 		rp->priv->rpi = (void *)rpi_msr;
 		break;
 	case RAPL_IF_TPMI:
-		rp->priv->defaults = (void *)&defaults_tpmi;
+		rp->priv->defaults = &defaults_tpmi;
 		rp->priv->rpi = (void *)rpi_tpmi;
 		break;
 	default:
@@ -806,7 +796,7 @@ static int rapl_config(struct rapl_package *rp)
 static enum rapl_primitives
 prim_fixups(struct rapl_domain *rd, enum rapl_primitives prim)
 {
-	struct rapl_defaults *defaults = get_defaults(rd->rp);
+	const struct rapl_defaults *defaults = get_defaults(rd->rp);
 
 	if (!defaults->spr_psys_bits)
 		return prim;
@@ -951,7 +941,7 @@ static int rapl_write_pl_data(struct rapl_domain *rd, int pl,
  * power unit : microWatts  : Represented in milliWatts by default
  * time unit  : microseconds: Represented in seconds by default
  */
-static int rapl_check_unit_core(struct rapl_domain *rd)
+int rapl_default_check_unit(struct rapl_domain *rd)
 {
 	struct reg_action ra;
 	u32 value;
@@ -978,6 +968,7 @@ static int rapl_check_unit_core(struct rapl_domain *rd)
 
 	return 0;
 }
+EXPORT_SYMBOL_NS_GPL(rapl_default_check_unit, "INTEL_RAPL");
 
 static int rapl_check_unit_atom(struct rapl_domain *rd)
 {
@@ -1071,7 +1062,7 @@ static void package_power_limit_irq_restore(struct rapl_package *rp)
 	wrmsr_safe(MSR_IA32_PACKAGE_THERM_INTERRUPT, l, h);
 }
 
-static void set_floor_freq_default(struct rapl_domain *rd, bool mode)
+void rapl_default_set_floor_freq(struct rapl_domain *rd, bool mode)
 {
 	int i;
 
@@ -1085,11 +1076,12 @@ static void set_floor_freq_default(struct rapl_domain *rd, bool mode)
 		rapl_write_pl_data(rd, i, PL_CLAMP, mode);
 	}
 }
+EXPORT_SYMBOL_NS_GPL(rapl_default_set_floor_freq, "INTEL_RAPL");
 
 static void set_floor_freq_atom(struct rapl_domain *rd, bool enable)
 {
 	static u32 power_ctrl_orig_val;
-	struct rapl_defaults *defaults = get_defaults(rd->rp);
+	const struct rapl_defaults *defaults = get_defaults(rd->rp);
 	u32 mdata;
 
 	if (!defaults->floor_freq_reg_addr) {
@@ -1110,8 +1102,7 @@ static void set_floor_freq_atom(struct rapl_domain *rd, bool enable)
 		       defaults->floor_freq_reg_addr, mdata);
 }
 
-static u64 rapl_compute_time_window_core(struct rapl_domain *rd, u64 value,
-					 bool to_raw)
+u64 rapl_default_compute_time_window(struct rapl_domain *rd, u64 value, bool to_raw)
 {
 	u64 f, y;		/* fraction and exp. used for time unit */
 
@@ -1142,6 +1133,7 @@ static u64 rapl_compute_time_window_core(struct rapl_domain *rd, u64 value,
 	}
 	return value;
 }
+EXPORT_SYMBOL_NS_GPL(rapl_default_compute_time_window, "INTEL_RAPL");
 
 static u64 rapl_compute_time_window_atom(struct rapl_domain *rd, u64 value,
 					 bool to_raw)
@@ -1187,28 +1179,28 @@ static int rapl_check_unit_tpmi(struct rapl_domain *rd)
 static const struct rapl_defaults defaults_tpmi = {
 	.check_unit = rapl_check_unit_tpmi,
 	/* Reuse existing logic, ignore the PL_CLAMP failures and enable all Power Limits */
-	.set_floor_freq = set_floor_freq_default,
-	.compute_time_window = rapl_compute_time_window_core,
+	.set_floor_freq = rapl_default_set_floor_freq,
+	.compute_time_window = rapl_default_compute_time_window,
 };
 
 static const struct rapl_defaults rapl_defaults_core = {
 	.floor_freq_reg_addr = 0,
-	.check_unit = rapl_check_unit_core,
-	.set_floor_freq = set_floor_freq_default,
-	.compute_time_window = rapl_compute_time_window_core,
+	.check_unit = rapl_default_check_unit,
+	.set_floor_freq = rapl_default_set_floor_freq,
+	.compute_time_window = rapl_default_compute_time_window,
 };
 
 static const struct rapl_defaults rapl_defaults_hsw_server = {
-	.check_unit = rapl_check_unit_core,
-	.set_floor_freq = set_floor_freq_default,
-	.compute_time_window = rapl_compute_time_window_core,
+	.check_unit = rapl_default_check_unit,
+	.set_floor_freq = rapl_default_set_floor_freq,
+	.compute_time_window = rapl_default_compute_time_window,
 	.dram_domain_energy_unit = 15300,
 };
 
 static const struct rapl_defaults rapl_defaults_spr_server = {
-	.check_unit = rapl_check_unit_core,
-	.set_floor_freq = set_floor_freq_default,
-	.compute_time_window = rapl_compute_time_window_core,
+	.check_unit = rapl_default_check_unit,
+	.set_floor_freq = rapl_default_set_floor_freq,
+	.compute_time_window = rapl_default_compute_time_window,
 	.psys_domain_energy_unit = NANOJOULE_PER_JOULE,
 	.spr_psys_bits = true,
 };
@@ -1242,7 +1234,7 @@ static const struct rapl_defaults rapl_defaults_cht = {
 };
 
 static const struct rapl_defaults rapl_defaults_amd = {
-	.check_unit = rapl_check_unit_core,
+	.check_unit = rapl_default_check_unit,
 };
 
 static const struct x86_cpu_id rapl_ids[] __initconst = {
@@ -1448,7 +1440,7 @@ static int rapl_check_domain(int domain, struct rapl_package *rp)
  */
 static int rapl_get_domain_unit(struct rapl_domain *rd)
 {
-	struct rapl_defaults *defaults = get_defaults(rd->rp);
+	const struct rapl_defaults *defaults = get_defaults(rd->rp);
 	int ret;
 
 	if (!rd->regs[RAPL_DOMAIN_REG_UNIT].val) {
@@ -2347,7 +2339,7 @@ static int __init rapl_init(void)
 
 	id = x86_match_cpu(rapl_ids);
 	if (id) {
-		defaults_msr = (struct rapl_defaults *)id->driver_data;
+		defaults_msr = (const struct rapl_defaults *)id->driver_data;
 
 		rapl_msr_platdev = platform_device_alloc("intel_rapl_msr", 0);
 		if (!rapl_msr_platdev)
diff --git a/include/linux/intel_rapl.h b/include/linux/intel_rapl.h
index f479ef5b3341..19f619fb37ff 100644
--- a/include/linux/intel_rapl.h
+++ b/include/linux/intel_rapl.h
@@ -128,6 +128,16 @@ struct reg_action {
 	int err;
 };
 
+struct rapl_defaults {
+	u8 floor_freq_reg_addr;
+	int (*check_unit)(struct rapl_domain *rd);
+	void (*set_floor_freq)(struct rapl_domain *rd, bool mode);
+	u64 (*compute_time_window)(struct rapl_domain *rd, u64 val, bool to_raw);
+	unsigned int dram_domain_energy_unit;
+	unsigned int psys_domain_energy_unit;
+	bool spr_psys_bits;
+};
+
 /**
  * struct rapl_if_priv: private data for different RAPL interfaces
  * @control_type:		Each RAPL interface must have its own powercap
@@ -142,7 +152,7 @@ struct reg_action {
  *				registers.
  * @write_raw:			Callback for writing RAPL interface specific
  *				registers.
- * @defaults:			internal pointer to interface default settings
+ * @defaults:			pointer to default settings
  * @rpi:			internal pointer to interface primitive info
  */
 struct rapl_if_priv {
@@ -154,7 +164,7 @@ struct rapl_if_priv {
 	int limits[RAPL_DOMAIN_MAX];
 	int (*read_raw)(int id, struct reg_action *ra, bool atomic);
 	int (*write_raw)(int id, struct reg_action *ra);
-	void *defaults;
+	const struct rapl_defaults *defaults;
 	void *rpi;
 };
 
@@ -211,6 +221,9 @@ void rapl_remove_package_cpuslocked(struct rapl_package *rp);
 struct rapl_package *rapl_find_package_domain(int id, struct rapl_if_priv *priv, bool id_is_cpu);
 struct rapl_package *rapl_add_package(int id, struct rapl_if_priv *priv, bool id_is_cpu);
 void rapl_remove_package(struct rapl_package *rp);
+int rapl_default_check_unit(struct rapl_domain *rd);
+void rapl_default_set_floor_freq(struct rapl_domain *rd, bool mode);
+u64 rapl_default_compute_time_window(struct rapl_domain *rd, u64 value, bool to_raw);
 
 #ifdef CONFIG_PERF_EVENTS
 int rapl_package_add_pmu(struct rapl_package *rp);
-- 
2.43.0

Powered by blists - more mailing lists