Merge back cpuidle material for 5.10.

* pm-cpuidle:
  cpuidle: record state entry rejection statistics
  cpuidle: psci: Allow PM domain to be initialized even if no OSI mode
  firmware: psci: Extend psci_set_osi_mode() to allow reset to PC mode
  ACPI: processor: Print more information when acpi_processor_evaluate_cst() fails
  cpuidle: tegra: Correctly handle result of arm_cpuidle_simple_enter()

Documentation/admin-guide/pm/cpuidle.rst

@@ -528,6 +528,10 @@ object corresponding to it, as follows:
 	Total number of times the hardware has been asked by the given CPU to
 	enter this idle state.
 
+``rejected``
+	Total number of times a request to enter this idle state on the given
+	CPU was rejected.
+
 The :file:`desc` and :file:`name` files both contain strings.  The difference
 between them is that the name is expected to be more concise, while the
 description may be longer and it may contain white space or special characters.
@@ -572,6 +576,11 @@ particular case.  For these reasons, the only reliable way to find out how
 much time has been spent by the hardware in different idle states supported by
 it is to use idle state residency counters in the hardware, if available.
 
+Generally, an interrupt received when trying to enter an idle state causes the
+idle state entry request to be rejected, in which case the ``CPUIdle`` driver
+may return an error code to indicate that this was the case. The :file:`usage`
+and :file:`rejected` files report the number of times the given idle state
+was entered successfully or rejected, respectively.
 
 .. _cpu-pm-qos:
 

drivers/acpi/acpi_processor.c

@@ -798,22 +798,34 @@ int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
 		memset(&cx, 0, sizeof(cx));
 
 		element = &cst->package.elements[i];
-		if (element->type != ACPI_TYPE_PACKAGE)
+		if (element->type != ACPI_TYPE_PACKAGE) {
+			acpi_handle_info(handle, "_CST C%d type(%x) is not package, skip...\n",
+					 i, element->type);
 			continue;
+		}
 
-		if (element->package.count != 4)
+		if (element->package.count != 4) {
+			acpi_handle_info(handle, "_CST C%d package count(%d) is not 4, skip...\n",
+					 i, element->package.count);
 			continue;
+		}
 
 		obj = &element->package.elements[0];
 
-		if (obj->type != ACPI_TYPE_BUFFER)
+		if (obj->type != ACPI_TYPE_BUFFER) {
+			acpi_handle_info(handle, "_CST C%d package element[0] type(%x) is not buffer, skip...\n",
+					 i, obj->type);
 			continue;
+		}
 
 		reg = (struct acpi_power_register *)obj->buffer.pointer;
 
 		obj = &element->package.elements[1];
-		if (obj->type != ACPI_TYPE_INTEGER)
+		if (obj->type != ACPI_TYPE_INTEGER) {
+			acpi_handle_info(handle, "_CST C[%d] package element[1] type(%x) is not integer, skip...\n",
+					 i, obj->type);
 			continue;
+		}
 
 		cx.type = obj->integer.value;
 		/*
@@ -850,6 +862,8 @@ int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
 				cx.entry_method = ACPI_CSTATE_HALT;
 				snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI HLT");
 			} else {
+				acpi_handle_info(handle, "_CST C%d declares FIXED_HARDWARE C-state but not supported in hardware, skip...\n",
+						 i);
 				continue;
 			}
 		} else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
@@ -857,6 +871,8 @@ int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
 			snprintf(cx.desc, ACPI_CX_DESC_LEN, "ACPI IOPORT 0x%x",
 				 cx.address);
 		} else {
+			acpi_handle_info(handle, "_CST C%d space_id(%x) neither FIXED_HARDWARE nor SYSTEM_IO, skip...\n",
+					 i, reg->space_id);
 			continue;
 		}
 
@@ -864,14 +880,20 @@ int acpi_processor_evaluate_cst(acpi_handle handle, u32 cpu,
 			cx.valid = 1;
 
 		obj = &element->package.elements[2];
-		if (obj->type != ACPI_TYPE_INTEGER)
+		if (obj->type != ACPI_TYPE_INTEGER) {
+			acpi_handle_info(handle, "_CST C%d package element[2] type(%x) not integer, skip...\n",
+					 i, obj->type);
 			continue;
+		}
 
 		cx.latency = obj->integer.value;
 
 		obj = &element->package.elements[3];
-		if (obj->type != ACPI_TYPE_INTEGER)
+		if (obj->type != ACPI_TYPE_INTEGER) {
+			acpi_handle_info(handle, "_CST C%d package element[3] type(%x) not integer, skip...\n",
+					 i, obj->type);
 			continue;
+		}
 
 		memcpy(&info->states[++last_index], &cx, sizeof(cx));
 	}

drivers/cpuidle/cpuidle-psci-domain.c

@@ -105,7 +105,7 @@ static void psci_pd_free_states(struct genpd_power_state *states,
 	kfree(states);
 }
 
-static int psci_pd_init(struct device_node *np)
+static int psci_pd_init(struct device_node *np, bool use_osi)
 {
 	struct generic_pm_domain *pd;
 	struct psci_pd_provider *pd_provider;
@@ -135,11 +135,16 @@ static int psci_pd_init(struct device_node *np)
 
 	pd->free_states = psci_pd_free_states;
 	pd->name = kbasename(pd->name);
-	pd->power_off = psci_pd_power_off;
 	pd->states = states;
 	pd->state_count = state_count;
 	pd->flags |= GENPD_FLAG_IRQ_SAFE | GENPD_FLAG_CPU_DOMAIN;
 
+	/* Allow power off when OSI has been successfully enabled. */
+	if (use_osi)
+		pd->power_off = psci_pd_power_off;
+	else
+		pd->flags |= GENPD_FLAG_ALWAYS_ON;
+
 	/* Use governor for CPU PM domains if it has some states to manage. */
 	pd_gov = state_count > 0 ? &pm_domain_cpu_gov : NULL;
 
@@ -190,7 +195,7 @@ static void psci_pd_remove(void)
 	}
 }
 
-static int psci_pd_init_topology(struct device_node *np, bool add)
+static int psci_pd_init_topology(struct device_node *np)
 {
 	struct device_node *node;
 	struct of_phandle_args child, parent;
@@ -203,9 +208,7 @@ static int psci_pd_init_topology(struct device_node *np, bool add)
 
 		child.np = node;
 		child.args_count = 0;
-
-		ret = add ? of_genpd_add_subdomain(&parent, &child) :
-			of_genpd_remove_subdomain(&parent, &child);
+		ret = of_genpd_add_subdomain(&parent, &child);
 		of_node_put(parent.np);
 		if (ret) {
 			of_node_put(node);
@@ -216,14 +219,20 @@ static int psci_pd_init_topology(struct device_node *np, bool add)
 	return 0;
 }
 
-static int psci_pd_add_topology(struct device_node *np)
+static bool psci_pd_try_set_osi_mode(void)
 {
-	return psci_pd_init_topology(np, true);
-}
+	int ret;
 
-static void psci_pd_remove_topology(struct device_node *np)
-{
-	psci_pd_init_topology(np, false);
+	if (!psci_has_osi_support())
+		return false;
+
+	ret = psci_set_osi_mode(true);
+	if (ret) {
+		pr_warn("failed to enable OSI mode: %d\n", ret);
+		return false;
+	}
+
+	return true;
 }
 
 static void psci_cpuidle_domain_sync_state(struct device *dev)
@@ -244,14 +253,14 @@ static int psci_cpuidle_domain_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct device_node *node;
+	bool use_osi;
 	int ret = 0, pd_count = 0;
 
 	if (!np)
 		return -ENODEV;
 
-	/* Currently limit the hierarchical topology to be used in OSI mode. */
-	if (!psci_has_osi_support())
-		return 0;
+	/* If OSI mode is supported, let's try to enable it. */
+	use_osi = psci_pd_try_set_osi_mode();
 
 	/*
 	 * Parse child nodes for the "#power-domain-cells" property and
@@ -261,7 +270,7 @@ static int psci_cpuidle_domain_probe(struct platform_device *pdev)
 		if (!of_find_property(node, "#power-domain-cells", NULL))
 			continue;
 
-		ret = psci_pd_init(node);
+		ret = psci_pd_init(node, use_osi);
 		if (ret)
 			goto put_node;
 
@@ -270,30 +279,24 @@ static int psci_cpuidle_domain_probe(struct platform_device *pdev)
 
 	/* Bail out if not using the hierarchical CPU topology. */
 	if (!pd_count)
-		return 0;
+		goto no_pd;
 
 	/* Link genpd masters/subdomains to model the CPU topology. */
-	ret = psci_pd_add_topology(np);
+	ret = psci_pd_init_topology(np);
 	if (ret)
 		goto remove_pd;
 
-	/* Try to enable OSI mode. */
-	ret = psci_set_osi_mode();
-	if (ret) {
-		pr_warn("failed to enable OSI mode: %d\n", ret);
-		psci_pd_remove_topology(np);
-		goto remove_pd;
-	}
-
 	pr_info("Initialized CPU PM domain topology\n");
 	return 0;
 
 put_node:
 	of_node_put(node);
 remove_pd:
-	if (pd_count)
-		psci_pd_remove();
+	psci_pd_remove();
 	pr_err("failed to create CPU PM domains ret=%d\n", ret);
+no_pd:
+	if (use_osi)
+		psci_set_osi_mode(false);
 	return ret;
 }
 

drivers/cpuidle/cpuidle-tegra.c

@@ -172,7 +172,7 @@ static int tegra_cpuidle_coupled_barrier(struct cpuidle_device *dev)
 static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
 				     int index, unsigned int cpu)
 {
-	int ret;
+	int err;
 
 	/*
 	 * CC6 state is the "CPU cluster power-off" state.  In order to
@@ -183,9 +183,9 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
 	 * CPU cores, GIC and L2 cache).
 	 */
 	if (index == TEGRA_CC6) {
-		ret = tegra_cpuidle_coupled_barrier(dev);
-		if (ret)
-			return ret;
+		err = tegra_cpuidle_coupled_barrier(dev);
+		if (err)
+			return err;
 	}
 
 	local_fiq_disable();
@@ -194,15 +194,15 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
 
 	switch (index) {
 	case TEGRA_C7:
-		ret = tegra_cpuidle_c7_enter();
+		err = tegra_cpuidle_c7_enter();
 		break;
 
 	case TEGRA_CC6:
-		ret = tegra_cpuidle_cc6_enter(cpu);
+		err = tegra_cpuidle_cc6_enter(cpu);
 		break;
 
 	default:
-		ret = -EINVAL;
+		err = -EINVAL;
 		break;
 	}
 
@@ -210,7 +210,7 @@ static int tegra_cpuidle_state_enter(struct cpuidle_device *dev,
 	tegra_pm_clear_cpu_in_lp2();
 	local_fiq_enable();
 
-	return ret;
+	return err ?: index;
 }
 
 static int tegra_cpuidle_adjust_state_index(int index, unsigned int cpu)
@@ -236,21 +236,27 @@ static int tegra_cpuidle_enter(struct cpuidle_device *dev,
 			       int index)
 {
 	unsigned int cpu = cpu_logical_map(dev->cpu);
-	int err;
+	int ret;
 
 	index = tegra_cpuidle_adjust_state_index(index, cpu);
 	if (dev->states_usage[index].disable)
 		return -1;
 
 	if (index == TEGRA_C1)
-		err = arm_cpuidle_simple_enter(dev, drv, index);
+		ret = arm_cpuidle_simple_enter(dev, drv, index);
 	else
-		err = tegra_cpuidle_state_enter(dev, index, cpu);
+		ret = tegra_cpuidle_state_enter(dev, index, cpu);
 
-	if (err && (err != -EINTR || index != TEGRA_CC6))
-		pr_err_once("failed to enter state %d err: %d\n", index, err);
+	if (ret < 0) {
+		if (ret != -EINTR || index != TEGRA_CC6)
+			pr_err_once("failed to enter state %d err: %d\n",
+				    index, ret);
+		index = -1;
+	} else {
+		index = ret;
+	}
 
-	return err ? -1 : index;
+	return index;
 }
 
 static int tegra114_enter_s2idle(struct cpuidle_device *dev,

drivers/cpuidle/cpuidle.c

@@ -297,6 +297,7 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
 		}
 	} else {
 		dev->last_residency_ns = 0;
+		dev->states_usage[index].rejected++;
 	}
 
 	return entered_state;

drivers/cpuidle/sysfs.c

@@ -256,6 +256,7 @@ define_show_state_time_function(exit_latency)
 define_show_state_time_function(target_residency)
 define_show_state_function(power_usage)
 define_show_state_ull_function(usage)
+define_show_state_ull_function(rejected)
 define_show_state_str_function(name)
 define_show_state_str_function(desc)
 define_show_state_ull_function(above)
@@ -312,6 +313,7 @@ define_one_state_ro(latency, show_state_exit_latency);
 define_one_state_ro(residency, show_state_target_residency);
 define_one_state_ro(power, show_state_power_usage);
 define_one_state_ro(usage, show_state_usage);
+define_one_state_ro(rejected, show_state_rejected);
 define_one_state_ro(time, show_state_time);
 define_one_state_rw(disable, show_state_disable, store_state_disable);
 define_one_state_ro(above, show_state_above);
@@ -325,6 +327,7 @@ static struct attribute *cpuidle_state_default_attrs[] = {
 	&attr_residency.attr,
 	&attr_power.attr,
 	&attr_usage.attr,
+	&attr_rejected.attr,
 	&attr_time.attr,
 	&attr_disable.attr,
 	&attr_above.attr,

drivers/firmware/psci/psci.c

@@ -151,12 +151,15 @@ static u32 psci_get_version(void)
 	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
 }
 
-int psci_set_osi_mode(void)
+int psci_set_osi_mode(bool enable)
 {
+	unsigned long suspend_mode;
 	int err;
 
-	err = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE,
-			     PSCI_1_0_SUSPEND_MODE_OSI, 0, 0);
+	suspend_mode = enable ? PSCI_1_0_SUSPEND_MODE_OSI :
+			PSCI_1_0_SUSPEND_MODE_PC;
+
+	err = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE, suspend_mode, 0, 0);
 	return psci_to_linux_errno(err);
 }
 
@@ -546,8 +549,7 @@ static int __init psci_1_0_init(struct device_node *np)
 		pr_info("OSI mode supported.\n");
 
 		/* Default to PC mode. */
-		invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE,
-			       PSCI_1_0_SUSPEND_MODE_PC, 0, 0);
+		psci_set_osi_mode(false);
 	}
 
 	return 0;

include/linux/cpuidle.h

@@ -38,6 +38,7 @@ struct cpuidle_state_usage {
 	u64			time_ns;
 	unsigned long long	above; /* Number of times it's been too deep */
 	unsigned long long	below; /* Number of times it's been too shallow */
+	unsigned long long	rejected; /* Number of times idle entry was rejected */
 #ifdef CONFIG_SUSPEND
 	unsigned long long	s2idle_usage;
 	unsigned long long	s2idle_time; /* in US */

include/linux/psci.h

@@ -18,7 +18,7 @@ bool psci_tos_resident_on(int cpu);
 
 int psci_cpu_suspend_enter(u32 state);
 bool psci_power_state_is_valid(u32 state);
-int psci_set_osi_mode(void);
+int psci_set_osi_mode(bool enable);
 bool psci_has_osi_support(void);
 
 struct psci_operations {