Merge tag 'pm-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "These add EPP support to the AMD P-state cpufreq driver, add support
  for new platforms to the Intel RAPL power capping driver, intel_idle
  and the Qualcomm cpufreq driver, enable thermal cooling for Tegra194,
  drop the custom cpufreq driver for loongson1 that is not necessary any
  more (and the corresponding cpufreq platform device), fix assorted
  issues and clean up code.

  Specifics:

   - Add EPP support to the AMD P-state cpufreq driver (Perry Yuan, Wyes
     Karny, Arnd Bergmann, Bagas Sanjaya)

   - Drop the custom cpufreq driver for loongson1 that is not necessary
     any more and the corresponding cpufreq platform device (Keguang
     Zhang)

   - Remove "select SRCU" from system sleep, cpufreq and OPP Kconfig
     entries (Paul E. McKenney)

   - Enable thermal cooling for Tegra194 (Yi-Wei Wang)

   - Register module device table and add missing compatibles for
     cpufreq-qcom-hw (Nícolas F. R. A. Prado, Abel Vesa and Luca Weiss)

   - Various dt binding updates for qcom-cpufreq-nvmem and
     opp-v2-kryo-cpu (Christian Marangi)

   - Make kobj_type structure in the cpufreq core constant (Thomas
     Weißschuh)

   - Make cpufreq_unregister_driver() return void (Uwe Kleine-König)

   - Make the TEO cpuidle governor check CPU utilization in order to
     refine idle state selection (Kajetan Puchalski)

   - Make Kconfig select the haltpoll cpuidle governor when the haltpoll
     cpuidle driver is selected and replace a default_idle() call in
     that driver with arch_cpu_idle() to allow MWAIT to be used (Li
     RongQing)

   - Add Emerald Rapids Xeon support to the intel_idle driver (Artem
     Bityutskiy)

   - Add ARCH_SUSPEND_POSSIBLE dependencies for ARMv4 cpuidle drivers to
     avoid randconfig build failures (Arnd Bergmann)

   - Make kobj_type structures used in the cpuidle sysfs interface
     constant (Thomas Weißschuh)

   - Make the cpuidle driver registration code update microsecond values
     of idle state parameters in accordance with their nanosecond values
     if they are provided (Rafael Wysocki)

   - Make the PSCI cpuidle driver prevent topology CPUs from being
     suspended on PREEMPT_RT (Krzysztof Kozlowski)

   - Document that pm_runtime_force_suspend() cannot be used with
     DPM_FLAG_SMART_SUSPEND (Richard Fitzgerald)

   - Add EXPORT macros for exporting PM functions from drivers (Richard
     Fitzgerald)

   - Remove /** from non-kernel-doc comments in hibernation code (Randy
     Dunlap)

   - Fix possible name leak in powercap_register_zone() (Yang Yingliang)

   - Add Meteor Lake and Emerald Rapids support to the intel_rapl power
     capping driver (Zhang Rui)

   - Modify the idle_inject power capping facility to support 100% idle
     injection (Srinivas Pandruvada)

   - Fix large time windows handling in the intel_rapl power capping
     driver (Zhang Rui)

   - Fix memory leaks with using debugfs_lookup() in the generic PM
     domains and Energy Model code (Greg Kroah-Hartman)

   - Add missing 'cache-unified' property in the example for kryo OPP
     bindings (Rob Herring)

   - Fix error checking in opp_migrate_dentry() (Qi Zheng)

   - Let qcom,opp-fuse-level be a 2-long array for qcom SoCs (Konrad
     Dybcio)

   - Modify some power management utilities to use the canonical ftrace
     path (Ross Zwisler)

   - Correct spelling problems for Documentation/power/ as reported by
     codespell (Randy Dunlap)"

* tag 'pm-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (53 commits)
  Documentation: amd-pstate: disambiguate user space sections
  cpufreq: amd-pstate: Fix invalid write to MSR_AMD_CPPC_REQ
  dt-bindings: opp: opp-v2-kryo-cpu: enlarge opp-supported-hw maximum
  dt-bindings: cpufreq: qcom-cpufreq-nvmem: make cpr bindings optional
  dt-bindings: cpufreq: qcom-cpufreq-nvmem: specify supported opp tables
  PM: Add EXPORT macros for exporting PM functions
  cpuidle: psci: Do not suspend topology CPUs on PREEMPT_RT
  MIPS: loongson32: Drop obsolete cpufreq platform device
  powercap: intel_rapl: Fix handling for large time window
  cpuidle: driver: Update microsecond values of state parameters as needed
  cpuidle: sysfs: make kobj_type structures constant
  cpuidle: add ARCH_SUSPEND_POSSIBLE dependencies
  PM: EM: fix memory leak with using debugfs_lookup()
  PM: domains: fix memory leak with using debugfs_lookup()
  cpufreq: Make kobj_type structure constant
  cpufreq: davinci: Fix clk use after free
  cpufreq: amd-pstate: avoid uninitialized variable use
  cpufreq: Make cpufreq_unregister_driver() return void
  OPP: fix error checking in opp_migrate_dentry()
  dt-bindings: cpufreq: cpufreq-qcom-hw: Add SM8550 compatible
  ...

8 files changed, 125 insertions, 10 deletions

diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index ff71dd662880d..cac5997dca505 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -74,6 +74,7 @@ endmenu
 config HALTPOLL_CPUIDLE
 	tristate "Halt poll cpuidle driver"
 	depends on X86 && KVM_GUEST
+	select CPU_IDLE_GOV_HALTPOLL
 	default y
 	help
 	 This option enables halt poll cpuidle driver, which allows to poll
diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
index 747aa537389b9..a1ee475d180da 100644
--- a/drivers/cpuidle/Kconfig.arm
+++ b/drivers/cpuidle/Kconfig.arm
@@ -24,6 +24,14 @@ config ARM_PSCI_CPUIDLE
 	  It provides an idle driver that is capable of detecting and
 	  managing idle states through the PSCI firmware interface.
 
+	  The driver has limitations when used with PREEMPT_RT:
+	  - If the idle states are described with the non-hierarchical layout,
+	    all idle states are still available.
+
+	  - If the idle states are described with the hierarchical layout,
+	    only the idle states defined per CPU are available, but not the ones
+	    being shared among a group of CPUs (aka cluster idle states).
+
 config ARM_PSCI_CPUIDLE_DOMAIN
 	bool "PSCI CPU idle Domain"
 	depends on ARM_PSCI_CPUIDLE
@@ -102,6 +110,7 @@ config ARM_MVEBU_V7_CPUIDLE
 config ARM_TEGRA_CPUIDLE
 	bool "CPU Idle Driver for NVIDIA Tegra SoCs"
 	depends on (ARCH_TEGRA || COMPILE_TEST) && !ARM64 && MMU
+	depends on ARCH_SUSPEND_POSSIBLE
 	select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
 	select ARM_CPU_SUSPEND
 	help
@@ -110,6 +119,7 @@ config ARM_TEGRA_CPUIDLE
 config ARM_QCOM_SPM_CPUIDLE
 	bool "CPU Idle Driver for Qualcomm Subsystem Power Manager (SPM)"
 	depends on (ARCH_QCOM || COMPILE_TEST) && !ARM64 && MMU
+	depends on ARCH_SUSPEND_POSSIBLE
 	select ARM_CPU_SUSPEND
 	select CPU_IDLE_MULTIPLE_DRIVERS
 	select DT_IDLE_STATES
diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
index 3a39a7f48b771..e66df22f96955 100644
--- a/drivers/cpuidle/cpuidle-haltpoll.c
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -32,7 +32,7 @@ static int default_enter_idle(struct cpuidle_device *dev,
 		local_irq_enable();
 		return index;
 	}
-	default_idle();
+	arch_cpu_idle();
 	return index;
 }
 
diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
index c80cf9ddabd8a..6ad2954948a5a 100644
--- a/drivers/cpuidle/cpuidle-psci-domain.c
+++ b/drivers/cpuidle/cpuidle-psci-domain.c
@@ -64,8 +64,11 @@ static int psci_pd_init(struct device_node *np, bool use_osi)
 
 	pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
 
-	/* Allow power off when OSI has been successfully enabled. */
-	if (use_osi)
+	/*
+	 * Allow power off when OSI has been successfully enabled.
+	 * PREEMPT_RT is not yet ready to enter domain idle states.
+	 */
+	if (use_osi && !IS_ENABLED(CONFIG_PREEMPT_RT))
 		pd->power_off = psci_pd_power_off;
 	else
 		pd->flags |= GENPD_FLAG_ALWAYS_ON;
diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index 312a34ef28dc3..6de027f9f6f59 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -222,6 +222,9 @@ static int psci_dt_cpu_init_topology(struct cpuidle_driver *drv,
 	if (!psci_has_osi_support())
 		return 0;
 
+	if (IS_ENABLED(CONFIG_PREEMPT_RT))
+		return 0;
+
 	data->dev = psci_dt_attach_cpu(cpu);
 	if (IS_ERR_OR_NULL(data->dev))
 		return PTR_ERR_OR_ZERO(data->dev);
diff --git a/drivers/cpuidle/driver.c b/drivers/cpuidle/driver.c
index f70aa17e2a8e0..d9cda7f6ccb98 100644
--- a/drivers/cpuidle/driver.c
+++ b/drivers/cpuidle/driver.c
@@ -183,11 +183,15 @@ static void __cpuidle_driver_init(struct cpuidle_driver *drv)
 			s->target_residency_ns = s->target_residency * NSEC_PER_USEC;
 		else if (s->target_residency_ns < 0)
 			s->target_residency_ns = 0;
+		else
+			s->target_residency = div_u64(s->target_residency_ns, NSEC_PER_USEC);
 
 		if (s->exit_latency > 0)
 			s->exit_latency_ns = s->exit_latency * NSEC_PER_USEC;
 		else if (s->exit_latency_ns < 0)
 			s->exit_latency_ns =  0;
+		else
+			s->exit_latency = div_u64(s->exit_latency_ns, NSEC_PER_USEC);
 	}
 }
 
diff --git a/drivers/cpuidle/governors/teo.c b/drivers/cpuidle/governors/teo.c
index d9262db79cae5..987fc5f3997dc 100644
--- a/drivers/cpuidle/governors/teo.c
+++ b/drivers/cpuidle/governors/teo.c
@@ -2,8 +2,13 @@
 /*
  * Timer events oriented CPU idle governor
  *
+ * TEO governor:
  * Copyright (C) 2018 - 2021 Intel Corporation
  * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ *
+ * Util-awareness mechanism:
+ * Copyright (C) 2022 Arm Ltd.
+ * Author: Kajetan Puchalski <kajetan.puchalski@arm.com>
  */
 
 /**
@@ -99,15 +104,56 @@
  *      select the given idle state instead of the candidate one.
  *
  * 3. By default, select the candidate state.
+ *
+ * Util-awareness mechanism:
+ *
+ * The idea behind the util-awareness extension is that there are two distinct
+ * scenarios for the CPU which should result in two different approaches to idle
+ * state selection - utilized and not utilized.
+ *
+ * In this case, 'utilized' means that the average runqueue util of the CPU is
+ * above a certain threshold.
+ *
+ * When the CPU is utilized while going into idle, more likely than not it will
+ * be woken up to do more work soon and so a shallower idle state should be
+ * selected to minimise latency and maximise performance. When the CPU is not
+ * being utilized, the usual metrics-based approach to selecting the deepest
+ * available idle state should be preferred to take advantage of the power
+ * saving.
+ *
+ * In order to achieve this, the governor uses a utilization threshold.
+ * The threshold is computed per-CPU as a percentage of the CPU's capacity
+ * by bit shifting the capacity value. Based on testing, the shift of 6 (~1.56%)
+ * seems to be getting the best results.
+ *
+ * Before selecting the next idle state, the governor compares the current CPU
+ * util to the precomputed util threshold. If it's below, it defaults to the
+ * TEO metrics mechanism. If it's above, the closest shallower idle state will
+ * be selected instead, as long as is not a polling state.
  */
 
 #include <linux/cpuidle.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
+#include <linux/sched.h>
 #include <linux/sched/clock.h>
+#include <linux/sched/topology.h>
 #include <linux/tick.h>
 
 /*
+ * The number of bits to shift the CPU's capacity by in order to determine
+ * the utilized threshold.
+ *
+ * 6 was chosen based on testing as the number that achieved the best balance
+ * of power and performance on average.
+ *
+ * The resulting threshold is high enough to not be triggered by background
+ * noise and low enough to react quickly when activity starts to ramp up.
+ */
+#define UTIL_THRESHOLD_SHIFT 6
+
+
+/*
  * The PULSE value is added to metrics when they grow and the DECAY_SHIFT value
  * is used for decreasing metrics on a regular basis.
  */
@@ -137,9 +183,11 @@ struct teo_bin {
  * @time_span_ns: Time between idle state selection and post-wakeup update.
  * @sleep_length_ns: Time till the closest timer event (at the selection time).
  * @state_bins: Idle state data bins for this CPU.
- * @total: Grand total of the "intercepts" and "hits" mertics for all bins.
+ * @total: Grand total of the "intercepts" and "hits" metrics for all bins.
  * @next_recent_idx: Index of the next @recent_idx entry to update.
  * @recent_idx: Indices of bins corresponding to recent "intercepts".
+ * @util_threshold: Threshold above which the CPU is considered utilized
+ * @utilized: Whether the last sleep on the CPU happened while utilized
  */
 struct teo_cpu {
 	s64 time_span_ns;
@@ -148,11 +196,30 @@ struct teo_cpu {
 	unsigned int total;
 	int next_recent_idx;
 	int recent_idx[NR_RECENT];
+	unsigned long util_threshold;
+	bool utilized;
 };
 
 static DEFINE_PER_CPU(struct teo_cpu, teo_cpus);
 
 /**
+ * teo_cpu_is_utilized - Check if the CPU's util is above the threshold
+ * @cpu: Target CPU
+ * @cpu_data: Governor CPU data for the target CPU
+ */
+#ifdef CONFIG_SMP
+static bool teo_cpu_is_utilized(int cpu, struct teo_cpu *cpu_data)
+{
+	return sched_cpu_util(cpu) > cpu_data->util_threshold;
+}
+#else
+static bool teo_cpu_is_utilized(int cpu, struct teo_cpu *cpu_data)
+{
+	return false;
+}
+#endif
+
+/**
  * teo_update - Update CPU metrics after wakeup.
  * @drv: cpuidle driver containing state data.
  * @dev: Target CPU.
@@ -258,15 +325,17 @@ static s64 teo_middle_of_bin(int idx, struct cpuidle_driver *drv)
  * @dev: Target CPU.
  * @state_idx: Index of the capping idle state.
  * @duration_ns: Idle duration value to match.
+ * @no_poll: Don't consider polling states.
  */
 static int teo_find_shallower_state(struct cpuidle_driver *drv,
 				    struct cpuidle_device *dev, int state_idx,
-				    s64 duration_ns)
+				    s64 duration_ns, bool no_poll)
 {
 	int i;
 
 	for (i = state_idx - 1; i >= 0; i--) {
-		if (dev->states_usage[i].disable)
+		if (dev->states_usage[i].disable ||
+				(no_poll && drv->states[i].flags & CPUIDLE_FLAG_POLLING))
 			continue;
 
 		state_idx = i;
@@ -321,6 +390,22 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 			goto end;
 	}
 
+	cpu_data->utilized = teo_cpu_is_utilized(dev->cpu, cpu_data);
+	/*
+	 * If the CPU is being utilized over the threshold and there are only 2
+	 * states to choose from, the metrics need not be considered, so choose
+	 * the shallowest non-polling state and exit.
+	 */
+	if (drv->state_count < 3 && cpu_data->utilized) {
+		for (i = 0; i < drv->state_count; ++i) {
+			if (!dev->states_usage[i].disable &&
+			    !(drv->states[i].flags & CPUIDLE_FLAG_POLLING)) {
+				idx = i;
+				goto end;
+			}
+		}
+	}
+
 	/*
 	 * Find the deepest idle state whose target residency does not exceed
 	 * the current sleep length and the deepest idle state not deeper than
@@ -452,6 +537,13 @@ static int teo_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 	if (idx > constraint_idx)
 		idx = constraint_idx;
 
+	/*
+	 * If the CPU is being utilized over the threshold, choose a shallower
+	 * non-polling state to improve latency
+	 */
+	if (cpu_data->utilized)
+		idx = teo_find_shallower_state(drv, dev, idx, duration_ns, true);
+
 end:
 	/*
 	 * Don't stop the tick if the selected state is a polling one or if the
@@ -469,7 +561,7 @@ end:
 		 */
 		if (idx > idx0 &&
 		    drv->states[idx].target_residency_ns > delta_tick)
-			idx = teo_find_shallower_state(drv, dev, idx, delta_tick);
+			idx = teo_find_shallower_state(drv, dev, idx, delta_tick, false);
 	}
 
 	return idx;
@@ -508,9 +600,11 @@ static int teo_enable_device(struct cpuidle_driver *drv,
 			     struct cpuidle_device *dev)
 {
 	struct teo_cpu *cpu_data = per_cpu_ptr(&teo_cpus, dev->cpu);
+	unsigned long max_capacity = arch_scale_cpu_capacity(dev->cpu);
 	int i;
 
 	memset(cpu_data, 0, sizeof(*cpu_data));
+	cpu_data->util_threshold = max_capacity >> UTIL_THRESHOLD_SHIFT;
 
 	for (i = 0; i < NR_RECENT; i++)
 		cpu_data->recent_idx[i] = -1;
diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 2b496a53cbca1..48948b1717494 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -200,7 +200,7 @@ static void cpuidle_sysfs_release(struct kobject *kobj)
 	complete(&kdev->kobj_unregister);
 }
 
-static struct kobj_type ktype_cpuidle = {
+static const struct kobj_type ktype_cpuidle = {
 	.sysfs_ops = &cpuidle_sysfs_ops,
 	.release = cpuidle_sysfs_release,
 };
@@ -447,7 +447,7 @@ static void cpuidle_state_sysfs_release(struct kobject *kobj)
 	complete(&state_obj->kobj_unregister);
 }
 
-static struct kobj_type ktype_state_cpuidle = {
+static const struct kobj_type ktype_state_cpuidle = {
 	.sysfs_ops = &cpuidle_state_sysfs_ops,
 	.default_groups = cpuidle_state_default_groups,
 	.release = cpuidle_state_sysfs_release,
@@ -594,7 +594,7 @@ static struct attribute *cpuidle_driver_default_attrs[] = {
 };
 ATTRIBUTE_GROUPS(cpuidle_driver_default);
 
-static struct kobj_type ktype_driver_cpuidle = {
+static const struct kobj_type ktype_driver_cpuidle = {
 	.sysfs_ops = &cpuidle_driver_sysfs_ops,
 	.default_groups = cpuidle_driver_default_groups,
 	.release = cpuidle_driver_sysfs_release,