Merge tag 'pm-5.9-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull one more power management update from Rafael Wysocki:
 "Modify the intel_pstate driver to allow it to work in the passive mode
  with hardware-managed P-states (HWP) enabled"

* tag 'pm-5.9-rc1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: intel_pstate: Implement passive mode with HWP enabled

2 files changed, 184 insertions, 67 deletions

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index afad06b91c77..02ab56b2a0d8 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -73,8 +73,6 @@ static inline bool has_target(void)
 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
 static int cpufreq_init_governor(struct cpufreq_policy *policy);
 static void cpufreq_exit_governor(struct cpufreq_policy *policy);
-static int cpufreq_start_governor(struct cpufreq_policy *policy);
-static void cpufreq_stop_governor(struct cpufreq_policy *policy);
 static void cpufreq_governor_limits(struct cpufreq_policy *policy);
 static int cpufreq_set_policy(struct cpufreq_policy *policy,
 			      struct cpufreq_governor *new_gov,
@@ -2266,7 +2264,7 @@ static void cpufreq_exit_governor(struct cpufreq_policy *policy)
 	module_put(policy->governor->owner);
 }
 
-static int cpufreq_start_governor(struct cpufreq_policy *policy)
+int cpufreq_start_governor(struct cpufreq_policy *policy)
 {
 	int ret;
 
@@ -2293,7 +2291,7 @@ static int cpufreq_start_governor(struct cpufreq_policy *policy)
 	return 0;
 }
 
-static void cpufreq_stop_governor(struct cpufreq_policy *policy)
+void cpufreq_stop_governor(struct cpufreq_policy *policy)
 {
 	if (cpufreq_suspended || !policy->governor)
 		return;
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index fc459c9c00ff..e0220a6fbc69 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -36,6 +36,7 @@
 #define INTEL_PSTATE_SAMPLING_INTERVAL	(10 * NSEC_PER_MSEC)
 
 #define INTEL_CPUFREQ_TRANSITION_LATENCY	20000
+#define INTEL_CPUFREQ_TRANSITION_DELAY_HWP	5000
 #define INTEL_CPUFREQ_TRANSITION_DELAY		500
 
 #ifdef CONFIG_ACPI
@@ -220,6 +221,7 @@ struct global_params {
  *			preference/bias
  * @epp_saved:		Saved EPP/EPB during system suspend or CPU offline
  *			operation
+ * @epp_cached		Cached HWP energy-performance preference value
  * @hwp_req_cached:	Cached value of the last HWP Request MSR
  * @hwp_cap_cached:	Cached value of the last HWP Capabilities MSR
  * @last_io_update:	Last time when IO wake flag was set
@@ -257,6 +259,7 @@ struct cpudata {
 	s16 epp_policy;
 	s16 epp_default;
 	s16 epp_saved;
+	s16 epp_cached;
 	u64 hwp_req_cached;
 	u64 hwp_cap_cached;
 	u64 last_io_update;
@@ -639,6 +642,26 @@ static int intel_pstate_get_energy_pref_index(struct cpudata *cpu_data, int *raw
 	return index;
 }
 
+static int intel_pstate_set_epp(struct cpudata *cpu, u32 epp)
+{
+	/*
+	 * Use the cached HWP Request MSR value, because in the active mode the
+	 * register itself may be updated by intel_pstate_hwp_boost_up() or
+	 * intel_pstate_hwp_boost_down() at any time.
+	 */
+	u64 value = READ_ONCE(cpu->hwp_req_cached);
+
+	value &= ~GENMASK_ULL(31, 24);
+	value |= (u64)epp << 24;
+	/*
+	 * The only other updater of hwp_req_cached in the active mode,
+	 * intel_pstate_hwp_set(), is called under the same lock as this
+	 * function, so it cannot run in parallel with the update below.
+	 */
+	WRITE_ONCE(cpu->hwp_req_cached, value);
+	return wrmsrl_on_cpu(cpu->cpu, MSR_HWP_REQUEST, value);
+}
+
 static int intel_pstate_set_energy_pref_index(struct cpudata *cpu_data,
 					      int pref_index, bool use_raw,
 					      u32 raw_epp)
@@ -650,28 +673,12 @@ static int intel_pstate_set_energy_pref_index(struct cpudata *cpu_data,
 		epp = cpu_data->epp_default;
 
 	if (boot_cpu_has(X86_FEATURE_HWP_EPP)) {
-		/*
-		 * Use the cached HWP Request MSR value, because the register
-		 * itself may be updated by intel_pstate_hwp_boost_up() or
-		 * intel_pstate_hwp_boost_down() at any time.
-		 */
-		u64 value = READ_ONCE(cpu_data->hwp_req_cached);
-
-		value &= ~GENMASK_ULL(31, 24);
-
 		if (use_raw)
 			epp = raw_epp;
 		else if (epp == -EINVAL)
 			epp = epp_values[pref_index - 1];
 
-		value |= (u64)epp << 24;
-		/*
-		 * The only other updater of hwp_req_cached in the active mode,
-		 * intel_pstate_hwp_set(), is called under the same lock as this
-		 * function, so it cannot run in parallel with the update below.
-		 */
-		WRITE_ONCE(cpu_data->hwp_req_cached, value);
-		ret = wrmsrl_on_cpu(cpu_data->cpu, MSR_HWP_REQUEST, value);
+		ret = intel_pstate_set_epp(cpu_data, epp);
 	} else {
 		if (epp == -EINVAL)
 			epp = (pref_index - 1) << 2;
@@ -697,10 +704,12 @@ static ssize_t show_energy_performance_available_preferences(
 
 cpufreq_freq_attr_ro(energy_performance_available_preferences);
 
+static struct cpufreq_driver intel_pstate;
+
 static ssize_t store_energy_performance_preference(
 		struct cpufreq_policy *policy, const char *buf, size_t count)
 {
-	struct cpudata *cpu_data = all_cpu_data[policy->cpu];
+	struct cpudata *cpu = all_cpu_data[policy->cpu];
 	char str_preference[21];
 	bool raw = false;
 	ssize_t ret;
@@ -725,15 +734,44 @@ static ssize_t store_energy_performance_preference(
 		raw = true;
 	}
 
+	/*
+	 * This function runs with the policy R/W semaphore held, which
+	 * guarantees that the driver pointer will not change while it is
+	 * running.
+	 */
+	if (!intel_pstate_driver)
+		return -EAGAIN;
+
 	mutex_lock(&intel_pstate_limits_lock);
 
-	ret = intel_pstate_set_energy_pref_index(cpu_data, ret, raw, epp);
-	if (!ret)
-		ret = count;
+	if (intel_pstate_driver == &intel_pstate) {
+		ret = intel_pstate_set_energy_pref_index(cpu, ret, raw, epp);
+	} else {
+		/*
+		 * In the passive mode the governor needs to be stopped on the
+		 * target CPU before the EPP update and restarted after it,
+		 * which is super-heavy-weight, so make sure it is worth doing
+		 * upfront.
+		 */
+		if (!raw)
+			epp = ret ? epp_values[ret - 1] : cpu->epp_default;
+
+		if (cpu->epp_cached != epp) {
+			int err;
+
+			cpufreq_stop_governor(policy);
+			ret = intel_pstate_set_epp(cpu, epp);
+			err = cpufreq_start_governor(policy);
+			if (!ret) {
+				cpu->epp_cached = epp;
+				ret = err;
+			}
+		}
+	}
 
 	mutex_unlock(&intel_pstate_limits_lock);
 
-	return ret;
+	return ret ?: count;
 }
 
 static ssize_t show_energy_performance_preference(
@@ -1145,8 +1183,6 @@ static ssize_t store_no_turbo(struct kobject *a, struct kobj_attribute *b,
 	return count;
 }
 
-static struct cpufreq_driver intel_pstate;
-
 static void update_qos_request(enum freq_qos_req_type type)
 {
 	int max_state, turbo_max, freq, i, perf_pct;
@@ -1330,9 +1366,10 @@ static const struct attribute_group intel_pstate_attr_group = {
 
 static const struct x86_cpu_id intel_pstate_cpu_ee_disable_ids[];
 
+static struct kobject *intel_pstate_kobject;
+
 static void __init intel_pstate_sysfs_expose_params(void)
 {
-	struct kobject *intel_pstate_kobject;
 	int rc;
 
 	intel_pstate_kobject = kobject_create_and_add("intel_pstate",
@@ -1357,17 +1394,31 @@ static void __init intel_pstate_sysfs_expose_params(void)
 	rc = sysfs_create_file(intel_pstate_kobject, &min_perf_pct.attr);
 	WARN_ON(rc);
 
-	if (hwp_active) {
-		rc = sysfs_create_file(intel_pstate_kobject,
-				       &hwp_dynamic_boost.attr);
-		WARN_ON(rc);
-	}
-
 	if (x86_match_cpu(intel_pstate_cpu_ee_disable_ids)) {
 		rc = sysfs_create_file(intel_pstate_kobject, &energy_efficiency.attr);
 		WARN_ON(rc);
 	}
 }
+
+static void intel_pstate_sysfs_expose_hwp_dynamic_boost(void)
+{
+	int rc;
+
+	if (!hwp_active)
+		return;
+
+	rc = sysfs_create_file(intel_pstate_kobject, &hwp_dynamic_boost.attr);
+	WARN_ON_ONCE(rc);
+}
+
+static void intel_pstate_sysfs_hide_hwp_dynamic_boost(void)
+{
+	if (!hwp_active)
+		return;
+
+	sysfs_remove_file(intel_pstate_kobject, &hwp_dynamic_boost.attr);
+}
+
 /************************** sysfs end ************************/
 
 static void intel_pstate_hwp_enable(struct cpudata *cpudata)
@@ -2247,7 +2298,10 @@ static int intel_pstate_verify_policy(struct cpufreq_policy_data *policy)
 
 static void intel_cpufreq_stop_cpu(struct cpufreq_policy *policy)
 {
-	intel_pstate_set_min_pstate(all_cpu_data[policy->cpu]);
+	if (hwp_active)
+		intel_pstate_hwp_force_min_perf(policy->cpu);
+	else
+		intel_pstate_set_min_pstate(all_cpu_data[policy->cpu]);
 }
 
 static void intel_pstate_stop_cpu(struct cpufreq_policy *policy)
@@ -2255,12 +2309,10 @@ static void intel_pstate_stop_cpu(struct cpufreq_policy *policy)
 	pr_debug("CPU %d exiting\n", policy->cpu);
 
 	intel_pstate_clear_update_util_hook(policy->cpu);
-	if (hwp_active) {
+	if (hwp_active)
 		intel_pstate_hwp_save_state(policy);
-		intel_pstate_hwp_force_min_perf(policy->cpu);
-	} else {
-		intel_cpufreq_stop_cpu(policy);
-	}
+
+	intel_cpufreq_stop_cpu(policy);
 }
 
 static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
@@ -2390,13 +2442,71 @@ static void intel_cpufreq_trace(struct cpudata *cpu, unsigned int trace_type, in
 		fp_toint(cpu->iowait_boost * 100));
 }
 
+static void intel_cpufreq_adjust_hwp(struct cpudata *cpu, u32 target_pstate,
+				     bool fast_switch)
+{
+	u64 prev = READ_ONCE(cpu->hwp_req_cached), value = prev;
+
+	value &= ~HWP_MIN_PERF(~0L);
+	value |= HWP_MIN_PERF(target_pstate);
+
+	/*
+	 * The entire MSR needs to be updated in order to update the HWP min
+	 * field in it, so opportunistically update the max too if needed.
+	 */
+	value &= ~HWP_MAX_PERF(~0L);
+	value |= HWP_MAX_PERF(cpu->max_perf_ratio);
+
+	if (value == prev)
+		return;
+
+	WRITE_ONCE(cpu->hwp_req_cached, value);
+	if (fast_switch)
+		wrmsrl(MSR_HWP_REQUEST, value);
+	else
+		wrmsrl_on_cpu(cpu->cpu, MSR_HWP_REQUEST, value);
+}
+
+static void intel_cpufreq_adjust_perf_ctl(struct cpudata *cpu,
+					  u32 target_pstate, bool fast_switch)
+{
+	if (fast_switch)
+		wrmsrl(MSR_IA32_PERF_CTL,
+		       pstate_funcs.get_val(cpu, target_pstate));
+	else
+		wrmsrl_on_cpu(cpu->cpu, MSR_IA32_PERF_CTL,
+			      pstate_funcs.get_val(cpu, target_pstate));
+}
+
+static int intel_cpufreq_update_pstate(struct cpudata *cpu, int target_pstate,
+				       bool fast_switch)
+{
+	int old_pstate = cpu->pstate.current_pstate;
+
+	target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
+	if (target_pstate != old_pstate) {
+		cpu->pstate.current_pstate = target_pstate;
+		if (hwp_active)
+			intel_cpufreq_adjust_hwp(cpu, target_pstate,
+						 fast_switch);
+		else
+			intel_cpufreq_adjust_perf_ctl(cpu, target_pstate,
+						      fast_switch);
+	}
+
+	intel_cpufreq_trace(cpu, fast_switch ? INTEL_PSTATE_TRACE_FAST_SWITCH :
+			    INTEL_PSTATE_TRACE_TARGET, old_pstate);
+
+	return target_pstate;
+}
+
 static int intel_cpufreq_target(struct cpufreq_policy *policy,
 				unsigned int target_freq,
 				unsigned int relation)
 {
 	struct cpudata *cpu = all_cpu_data[policy->cpu];
 	struct cpufreq_freqs freqs;
-	int target_pstate, old_pstate;
+	int target_pstate;
 
 	update_turbo_state();
 
@@ -2404,6 +2514,7 @@ static int intel_cpufreq_target(struct cpufreq_policy *policy,
 	freqs.new = target_freq;
 
 	cpufreq_freq_transition_begin(policy, &freqs);
+
 	switch (relation) {
 	case CPUFREQ_RELATION_L:
 		target_pstate = DIV_ROUND_UP(freqs.new, cpu->pstate.scaling);
@@ -2415,15 +2526,11 @@ static int intel_cpufreq_target(struct cpufreq_policy *policy,
 		target_pstate = DIV_ROUND_CLOSEST(freqs.new, cpu->pstate.scaling);
 		break;
 	}
-	target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
-	old_pstate = cpu->pstate.current_pstate;
-	if (target_pstate != cpu->pstate.current_pstate) {
-		cpu->pstate.current_pstate = target_pstate;
-		wrmsrl_on_cpu(policy->cpu, MSR_IA32_PERF_CTL,
-			      pstate_funcs.get_val(cpu, target_pstate));
-	}
+
+	target_pstate = intel_cpufreq_update_pstate(cpu, target_pstate, false);
+
 	freqs.new = target_pstate * cpu->pstate.scaling;
-	intel_cpufreq_trace(cpu, INTEL_PSTATE_TRACE_TARGET, old_pstate);
+
 	cpufreq_freq_transition_end(policy, &freqs, false);
 
 	return 0;
@@ -2433,15 +2540,14 @@ static unsigned int intel_cpufreq_fast_switch(struct cpufreq_policy *policy,
 					      unsigned int target_freq)
 {
 	struct cpudata *cpu = all_cpu_data[policy->cpu];
-	int target_pstate, old_pstate;
+	int target_pstate;
 
 	update_turbo_state();
 
 	target_pstate = DIV_ROUND_UP(target_freq, cpu->pstate.scaling);
-	target_pstate = intel_pstate_prepare_request(cpu, target_pstate);
-	old_pstate = cpu->pstate.current_pstate;
-	intel_pstate_update_pstate(cpu, target_pstate);
-	intel_cpufreq_trace(cpu, INTEL_PSTATE_TRACE_FAST_SWITCH, old_pstate);
+
+	target_pstate = intel_cpufreq_update_pstate(cpu, target_pstate, true);
+
 	return target_pstate * cpu->pstate.scaling;
 }
 
@@ -2461,7 +2567,6 @@ static int intel_cpufreq_cpu_init(struct cpufreq_policy *policy)
 		return ret;
 
 	policy->cpuinfo.transition_latency = INTEL_CPUFREQ_TRANSITION_LATENCY;
-	policy->transition_delay_us = INTEL_CPUFREQ_TRANSITION_DELAY;
 	/* This reflects the intel_pstate_get_cpu_pstates() setting. */
 	policy->cur = policy->cpuinfo.min_freq;
 
@@ -2473,10 +2578,18 @@ static int intel_cpufreq_cpu_init(struct cpufreq_policy *policy)
 
 	cpu = all_cpu_data[policy->cpu];
 
-	if (hwp_active)
+	if (hwp_active) {
+		u64 value;
+
 		intel_pstate_get_hwp_max(policy->cpu, &turbo_max, &max_state);
-	else
+		policy->transition_delay_us = INTEL_CPUFREQ_TRANSITION_DELAY_HWP;
+		rdmsrl_on_cpu(cpu->cpu, MSR_HWP_REQUEST, &value);
+		WRITE_ONCE(cpu->hwp_req_cached, value);
+		cpu->epp_cached = (value & GENMASK_ULL(31, 24)) >> 24;
+	} else {
 		turbo_max = cpu->pstate.turbo_pstate;
+		policy->transition_delay_us = INTEL_CPUFREQ_TRANSITION_DELAY;
+	}
 
 	min_freq = DIV_ROUND_UP(turbo_max * global.min_perf_pct, 100);
 	min_freq *= cpu->pstate.scaling;
@@ -2553,6 +2666,10 @@ static void intel_pstate_driver_cleanup(void)
 		}
 	}
 	put_online_cpus();
+
+	if (intel_pstate_driver == &intel_pstate)
+		intel_pstate_sysfs_hide_hwp_dynamic_boost();
+
 	intel_pstate_driver = NULL;
 }
 
@@ -2560,6 +2677,9 @@ static int intel_pstate_register_driver(struct cpufreq_driver *driver)
 {
 	int ret;
 
+	if (driver == &intel_pstate)
+		intel_pstate_sysfs_expose_hwp_dynamic_boost();
+
 	memset(&global, 0, sizeof(global));
 	global.max_perf_pct = 100;
 
@@ -2577,9 +2697,6 @@ static int intel_pstate_register_driver(struct cpufreq_driver *driver)
 
 static int intel_pstate_unregister_driver(void)
 {
-	if (hwp_active)
-		return -EBUSY;
-
 	cpufreq_unregister_driver(intel_pstate_driver);
 	intel_pstate_driver_cleanup();
 
@@ -2835,7 +2952,10 @@ static int __init intel_pstate_init(void)
 			hwp_active++;
 			hwp_mode_bdw = id->driver_data;
 			intel_pstate.attr = hwp_cpufreq_attrs;
-			default_driver = &intel_pstate;
+			intel_cpufreq.attr = hwp_cpufreq_attrs;
+			if (!default_driver)
+				default_driver = &intel_pstate;
+
 			goto hwp_cpu_matched;
 		}
 	} else {
@@ -2906,14 +3026,13 @@ static int __init intel_pstate_setup(char *str)
 	if (!str)
 		return -EINVAL;
 
-	if (!strcmp(str, "disable")) {
+	if (!strcmp(str, "disable"))
 		no_load = 1;
-	} else if (!strcmp(str, "active")) {
+	else if (!strcmp(str, "active"))
 		default_driver = &intel_pstate;
-	} else if (!strcmp(str, "passive")) {
+	else if (!strcmp(str, "passive"))
 		default_driver = &intel_cpufreq;
-		no_hwp = 1;
-	}
+
 	if (!strcmp(str, "no_hwp")) {
 		pr_info("HWP disabled\n");
 		no_hwp = 1;