Merge branches 'pm-qos' and 'pm-tools'

Merge PM QoS updates and a cpupower utility update for 6.19-rc1:

- Introduce and document a QoS limit on CPU exit latency during wakeup
from suspend-to-idle (Ulf Hansson)

- Add support for building libcpupower statically (Zuo An)

* pm-qos:
Documentation: power/cpuidle: Document the CPU system wakeup latency QoS
cpuidle: Respect the CPU system wakeup QoS limit for cpuidle
sched: idle: Respect the CPU system wakeup QoS limit for s2idle
pmdomain: Respect the CPU system wakeup QoS limit for cpuidle
pmdomain: Respect the CPU system wakeup QoS limit for s2idle
PM: QoS: Introduce a CPU system wakeup QoS limit

* pm-tools:
tools/power/cpupower: Support building libcpupower statically

Documentation/admin-guide/pm/cpuidle.rst

···
 they are allowed to select for that CPU.  They should never select any idle
 states with exit latency beyond that limit.
 
+While the above CPU QoS constraints apply to CPU idle time management, user
+space may also request a CPU system wakeup latency QoS limit, via the
+`cpu_wakeup_latency` file.  This QoS constraint is respected when selecting a
+suitable idle state for the CPUs, while entering the system-wide suspend-to-idle
+sleep state, but also to the regular CPU idle time management.
+
+Note that, the management of the `cpu_wakeup_latency` file works according to
+the 'cpu_dma_latency' file from user space point of view.  Moreover, the unit
+is also microseconds.
 
 Idle States Control Via Kernel Command Line
 ===========================================

Documentation/power/pm_qos_interface.rst

···
 
 From user space:
 
-The infrastructure exposes one device node, /dev/cpu_dma_latency, for the CPU
+The infrastructure exposes two separate device nodes, /dev/cpu_dma_latency for
+the CPU latency QoS and /dev/cpu_wakeup_latency for the CPU system wakeup
 latency QoS.
 
 Only processes can register a PM QoS request.  To provide for automatic
···
 parameter requests as follows.
 
 To register the default PM QoS target for the CPU latency QoS, the process must
-open /dev/cpu_dma_latency.
+open /dev/cpu_dma_latency.  To register a CPU system wakeup QoS limit, the
+process must open /dev/cpu_wakeup_latency.
 
 As long as the device node is held open that process has a registered
 request on the parameter.
 
 To change the requested target value, the process needs to write an s32 value to
 the open device node.  Alternatively, it can write a hex string for the value
-using the 10 char long format e.g. "0x12345678".  This translates to a
-cpu_latency_qos_update_request() call.
+using the 10 char long format e.g. "0x12345678".
 
 To remove the user mode request for a target value simply close the device
 node.

drivers/cpuidle/cpuidle.c

···
  * cpuidle_enter_s2idle - Enter an idle state suitable for suspend-to-idle.
  * @drv: cpuidle driver for the given CPU.
  * @dev: cpuidle device for the given CPU.
+ * @latency_limit_ns: Idle state exit latency limit
  *
  * If there are states with the ->enter_s2idle callback, find the deepest of
  * them and enter it with frozen tick.
  */
-int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev)
+int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
+			 u64 latency_limit_ns)
 {
 	int index;
 
 	/*
-	 * Find the deepest state with ->enter_s2idle present, which guarantees
-	 * that interrupts won't be enabled when it exits and allows the tick to
-	 * be frozen safely.
+	 * Find the deepest state with ->enter_s2idle present that meets the
+	 * specified latency limit, which guarantees that interrupts won't be
+	 * enabled when it exits and allows the tick to be frozen safely.
 	 */
-	index = find_deepest_state(drv, dev, U64_MAX, 0, true);
+	index = find_deepest_state(drv, dev, latency_limit_ns, 0, true);
 	if (index > 0) {
 		enter_s2idle_proper(drv, dev, index);
 		local_irq_enable();

drivers/cpuidle/governor.c

···
 	struct device *device = get_cpu_device(cpu);
 	int device_req = dev_pm_qos_raw_resume_latency(device);
 	int global_req = cpu_latency_qos_limit();
+	int global_wake_req = cpu_wakeup_latency_qos_limit();
+
+	if (global_req > global_wake_req)
+		global_req = global_wake_req;
 
 	if (device_req > global_req)
 		device_req = global_req;

drivers/pmdomain/core.c

···
 			return;
 	}
 
-	/* Choose the deepest state when suspending */
-	genpd->state_idx = genpd->state_count - 1;
+	if (genpd->gov && genpd->gov->system_power_down_ok) {
+		if (!genpd->gov->system_power_down_ok(&genpd->domain))
+			return;
+	} else {
+		/* Default to the deepest state. */
+		genpd->state_idx = genpd->state_count - 1;
+	}
+
 	if (_genpd_power_off(genpd, false)) {
 		genpd->states[genpd->state_idx].rejected++;
 		return;

drivers/pmdomain/governor.c

···
 	ktime_t domain_wakeup, next_hrtimer;
 	ktime_t now = ktime_get();
 	struct device *cpu_dev;
-	s64 cpu_constraint, global_constraint;
+	s64 cpu_constraint, global_constraint, wakeup_constraint;
 	s64 idle_duration_ns;
 	int cpu, i;
 
···
 	if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN))
 		return true;
 
+	wakeup_constraint = cpu_wakeup_latency_qos_limit();
 	global_constraint = cpu_latency_qos_limit();
+	if (global_constraint > wakeup_constraint)
+		global_constraint = wakeup_constraint;
+
 	/*
 	 * Find the next wakeup for any of the online CPUs within the PM domain
 	 * and its subdomains. Note, we only need the genpd->cpus, as it already
···
 	return false;
 }
 
+static bool cpu_system_power_down_ok(struct dev_pm_domain *pd)
+{
+	s64 constraint_ns = cpu_wakeup_latency_qos_limit() * NSEC_PER_USEC;
+	struct generic_pm_domain *genpd = pd_to_genpd(pd);
+	int state_idx = genpd->state_count - 1;
+
+	if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN)) {
+		genpd->state_idx = state_idx;
+		return true;
+	}
+
+	/* Find the deepest state for the latency constraint. */
+	while (state_idx >= 0) {
+		s64 latency_ns = genpd->states[state_idx].power_off_latency_ns +
+				 genpd->states[state_idx].power_on_latency_ns;
+
+		if (latency_ns <= constraint_ns) {
+			genpd->state_idx = state_idx;
+			return true;
+		}
+		state_idx--;
+	}
+
+	return false;
+}
+
 struct dev_power_governor pm_domain_cpu_gov = {
 	.suspend_ok = default_suspend_ok,
 	.power_down_ok = cpu_power_down_ok,
+	.system_power_down_ok = cpu_system_power_down_ok,
 };
 #endif
 

include/linux/cpuidle.h

···
 				      struct cpuidle_device *dev,
 				      u64 latency_limit_ns);
 extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
-				struct cpuidle_device *dev);
+				struct cpuidle_device *dev,
+				u64 latency_limit_ns);
 extern void cpuidle_use_deepest_state(u64 latency_limit_ns);
 #else
 static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
···
 					     u64 latency_limit_ns)
 {return -ENODEV; }
 static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
-				       struct cpuidle_device *dev)
+				       struct cpuidle_device *dev,
+				       u64 latency_limit_ns)
 {return -ENODEV; }
 static inline void cpuidle_use_deepest_state(u64 latency_limit_ns)
 {

include/linux/pm_domain.h

···
 };
 
 struct dev_power_governor {
+	bool (*system_power_down_ok)(struct dev_pm_domain *domain);
 	bool (*power_down_ok)(struct dev_pm_domain *domain);
 	bool (*suspend_ok)(struct device *dev);
 };

include/linux/pm_qos.h

···
 static inline void cpu_latency_qos_remove_request(struct pm_qos_request *req) {}
 #endif
 
+#ifdef CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP
+s32 cpu_wakeup_latency_qos_limit(void);
+#else
+static inline s32 cpu_wakeup_latency_qos_limit(void)
+{
+	return PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
+}
+#endif
+
 #ifdef CONFIG_PM
 enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev, s32 mask);
 enum pm_qos_flags_status dev_pm_qos_flags(struct device *dev, s32 mask);

kernel/power/Kconfig

···
 	depends on PM_WAKELOCKS
 	default y
 
+config PM_QOS_CPU_SYSTEM_WAKEUP
+	bool "User space interface for CPU system wakeup QoS"
+	depends on CPU_IDLE
+	help
+	  Enable this to allow user space via the cpu_wakeup_latency file to
+	  specify a CPU system wakeup latency limit.
+
+	  This may be particularly useful for platforms supporting multiple low
+	  power states for CPUs during system-wide suspend and s2idle in
+	  particular.
+
 config PM
 	bool "Device power management core functionality"
 	help

kernel/power/qos.c

···
 	.fops = &cpu_latency_qos_fops,
 };
 
+#ifdef CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP
+/* The CPU system wakeup latency QoS. */
+static struct pm_qos_constraints cpu_wakeup_latency_constraints = {
+	.list = PLIST_HEAD_INIT(cpu_wakeup_latency_constraints.list),
+	.target_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT,
+	.default_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT,
+	.no_constraint_value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT,
+	.type = PM_QOS_MIN,
+};
+
+/**
+ * cpu_wakeup_latency_qos_limit - Current CPU system wakeup latency QoS limit.
+ *
+ * Returns the current CPU system wakeup latency QoS limit that may have been
+ * requested by user space.
+ */
+s32 cpu_wakeup_latency_qos_limit(void)
+{
+	return pm_qos_read_value(&cpu_wakeup_latency_constraints);
+}
+
+static int cpu_wakeup_latency_qos_open(struct inode *inode, struct file *filp)
+{
+	struct pm_qos_request *req;
+
+	req = kzalloc(sizeof(*req), GFP_KERNEL);
+	if (!req)
+		return -ENOMEM;
+
+	req->qos = &cpu_wakeup_latency_constraints;
+	pm_qos_update_target(req->qos, &req->node, PM_QOS_ADD_REQ,
+			     PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
+	filp->private_data = req;
+
+	return 0;
+}
+
+static int cpu_wakeup_latency_qos_release(struct inode *inode,
+					  struct file *filp)
+{
+	struct pm_qos_request *req = filp->private_data;
+
+	filp->private_data = NULL;
+	pm_qos_update_target(req->qos, &req->node, PM_QOS_REMOVE_REQ,
+			     PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
+	kfree(req);
+
+	return 0;
+}
+
+static ssize_t cpu_wakeup_latency_qos_read(struct file *filp, char __user *buf,
+					   size_t count, loff_t *f_pos)
+{
+	s32 value = pm_qos_read_value(&cpu_wakeup_latency_constraints);
+
+	return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
+}
+
+static ssize_t cpu_wakeup_latency_qos_write(struct file *filp,
+					    const char __user *buf,
+					    size_t count, loff_t *f_pos)
+{
+	struct pm_qos_request *req = filp->private_data;
+	s32 value;
+
+	if (count == sizeof(s32)) {
+		if (copy_from_user(&value, buf, sizeof(s32)))
+			return -EFAULT;
+	} else {
+		int ret;
+
+		ret = kstrtos32_from_user(buf, count, 16, &value);
+		if (ret)
+			return ret;
+	}
+
+	if (value < 0)
+		return -EINVAL;
+
+	pm_qos_update_target(req->qos, &req->node, PM_QOS_UPDATE_REQ, value);
+
+	return count;
+}
+
+static const struct file_operations cpu_wakeup_latency_qos_fops = {
+	.open = cpu_wakeup_latency_qos_open,
+	.release = cpu_wakeup_latency_qos_release,
+	.read = cpu_wakeup_latency_qos_read,
+	.write = cpu_wakeup_latency_qos_write,
+	.llseek = noop_llseek,
+};
+
+static struct miscdevice cpu_wakeup_latency_qos_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "cpu_wakeup_latency",
+	.fops = &cpu_wakeup_latency_qos_fops,
+};
+#endif /* CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP */
+
 static int __init cpu_latency_qos_init(void)
 {
 	int ret;
···
 	if (ret < 0)
 		pr_err("%s: %s setup failed\n", __func__,
 		       cpu_latency_qos_miscdev.name);
+
+#ifdef CONFIG_PM_QOS_CPU_SYSTEM_WAKEUP
+	ret = misc_register(&cpu_wakeup_latency_qos_miscdev);
+	if (ret < 0)
+		pr_err("%s: %s setup failed\n", __func__,
+		       cpu_wakeup_latency_qos_miscdev.name);
+#endif
 
 	return ret;
 }

kernel/sched/idle.c

···
 }
 
 static int call_cpuidle_s2idle(struct cpuidle_driver *drv,
-			       struct cpuidle_device *dev)
+			       struct cpuidle_device *dev,
+			       u64 max_latency_ns)
 {
 	if (current_clr_polling_and_test())
 		return -EBUSY;
 
-	return cpuidle_enter_s2idle(drv, dev);
+	return cpuidle_enter_s2idle(drv, dev, max_latency_ns);
 }
 
 static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
···
 		u64 max_latency_ns;
 
 		if (idle_should_enter_s2idle()) {
+			max_latency_ns = cpu_wakeup_latency_qos_limit() *
+					 NSEC_PER_USEC;
 
-			entered_state = call_cpuidle_s2idle(drv, dev);
+			entered_state = call_cpuidle_s2idle(drv, dev,
+							    max_latency_ns);
 			if (entered_state > 0)
 				goto exit_idle;
-
-			max_latency_ns = U64_MAX;
 		} else {
 			max_latency_ns = dev->forced_idle_latency_limit_ns;
 		}

tools/power/cpupower/Makefile

···
 # cpufreq-bench benchmarking tool
 CPUFREQ_BENCH ?= true
 
-# Do not build libraries, but build the code in statically
-# Libraries are still built, otherwise the Makefile code would
-# be rather ugly.
+# Build the code, including libraries, statically.
 export STATIC ?= false
 
 # Prefix to the directories we're installing to
···
 	$(ECHO) "  CC      " $@
 	$(QUIET) $(CC) $(CFLAGS) -fPIC -o $@ -c lib/$*.c
 
-$(OUTPUT)libcpupower.so.$(LIB_VER): $(LIB_OBJS)
+ifeq ($(strip $(STATIC)),true)
+LIBCPUPOWER := libcpupower.a
+else
+LIBCPUPOWER := libcpupower.so.$(LIB_VER)
+endif
+
+$(OUTPUT)$(LIBCPUPOWER): $(LIB_OBJS)
+ifeq ($(strip $(STATIC)),true)
+	$(ECHO) "  AR      " $@
+	$(QUIET) $(AR) rcs $@ $(LIB_OBJS)
+else
 	$(ECHO) "  LD      " $@
 	$(QUIET) $(CC) -shared $(CFLAGS) $(LDFLAGS) -o $@ \
 		-Wl,-soname,libcpupower.so.$(LIB_MAJ) $(LIB_OBJS)
 	@ln -sf $(@F) $(OUTPUT)libcpupower.so
 	@ln -sf $(@F) $(OUTPUT)libcpupower.so.$(LIB_MAJ)
+endif
 
-libcpupower: $(OUTPUT)libcpupower.so.$(LIB_VER)
+libcpupower: $(OUTPUT)$(LIBCPUPOWER)
 
 # Let all .o files depend on its .c file and all headers
 # Might be worth to put this into utils/Makefile at some point of time
···
 	$(ECHO) "  CC      " $@
 	$(QUIET) $(CC) $(CFLAGS) -I./lib -I ./utils -o $@ -c $*.c
 
-$(OUTPUT)cpupower: $(UTIL_OBJS) $(OUTPUT)libcpupower.so.$(LIB_VER)
+$(OUTPUT)cpupower: $(UTIL_OBJS) $(OUTPUT)$(LIBCPUPOWER)
 	$(ECHO) "  CC      " $@
 ifeq ($(strip $(STATIC)),true)
 	$(QUIET) $(CC) $(CFLAGS) $(LDFLAGS) $(UTIL_OBJS) -lrt -lpci -L$(OUTPUT) -o $@
···
 	done;
 endif
 
-compile-bench: $(OUTPUT)libcpupower.so.$(LIB_VER)
+compile-bench: $(OUTPUT)$(LIBCPUPOWER)
 	@V=$(V) confdir=$(confdir) $(MAKE) -C bench O=$(OUTPUT)
 
 # we compile into subdirectories. if the target directory is not the
···
 	-find $(OUTPUT) \( -not -type d \) -and \( -name '*~' -o -name '*.[oas]' \) -type f -print \
 	 | xargs rm -f
 	-rm -f $(OUTPUT)cpupower
+	-rm -f $(OUTPUT)libcpupower.a
 	-rm -f $(OUTPUT)libcpupower.so*
 	-rm -rf $(OUTPUT)po/*.gmo
 	-rm -rf $(OUTPUT)po/*.pot
···
 
 install-lib: libcpupower
 	$(INSTALL) -d $(DESTDIR)${libdir}
+ifeq ($(strip $(STATIC)),true)
+	$(CP) $(OUTPUT)libcpupower.a $(DESTDIR)${libdir}/
+else
 	$(CP) $(OUTPUT)libcpupower.so* $(DESTDIR)${libdir}/
+endif
 	$(INSTALL) -d $(DESTDIR)${includedir}
 	$(INSTALL_DATA) lib/cpufreq.h $(DESTDIR)${includedir}/cpufreq.h
 	$(INSTALL_DATA) lib/cpuidle.h $(DESTDIR)${includedir}/cpuidle.h
···
 	@#DESTDIR must be set from outside to survive
 	@sbindir=$(sbindir) bindir=$(bindir) docdir=$(docdir) confdir=$(confdir) $(MAKE) -C bench O=$(OUTPUT) install
 
-ifeq ($(strip $(STATIC)),true)
-install: all install-tools install-man $(INSTALL_NLS) $(INSTALL_BENCH)
-else
 install: all install-lib install-tools install-man $(INSTALL_NLS) $(INSTALL_BENCH)
-endif
 
 uninstall:
 	- rm -f $(DESTDIR)${libdir}/libcpupower.*