arm, arm64: factorize common cpu capacity default code
authorJuri Lelli <juri.lelli@arm.com>
Wed, 31 May 2017 16:59:28 +0000 (17:59 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 3 Jun 2017 10:10:09 +0000 (19:10 +0900)
arm and arm64 share lot of code relative to parsing CPU capacity
information from DT, using that information for appropriate scaling and
exposing a sysfs interface for chaging such values at runtime.

Factorize such code in a common place (driver/base/arch_topology.c) in
preparation for further additions.

Suggested-by: Will Deacon <will.deacon@arm.com>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/arm/Kconfig
arch/arm/kernel/topology.c
arch/arm64/Kconfig
arch/arm64/kernel/topology.c
drivers/base/Kconfig
drivers/base/Makefile
drivers/base/arch_topology.c [new file with mode: 0644]

index 4c1a35f1583872d2ce39db5c1cacce28be48ccb1..7ef16700cb884d5b6105bff913ebbe01c6c8b2c1 100644 (file)
@@ -25,6 +25,7 @@ config ARM
        select EDAC_SUPPORT
        select EDAC_ATOMIC_SCRUB
        select GENERIC_ALLOCATOR
+       select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY
        select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI)
        select GENERIC_CLOCKEVENTS_BROADCAST if SMP
        select GENERIC_CPU_AUTOPROBE
index 40dd35aa46d004359507d08948b7cad059a6214a..49ef025ffaa01df6d36b8e5e8daef861ee961783 100644 (file)
  * to run the rebalance_domains for all idle cores and the cpu_capacity can be
  * updated during this sequence.
  */
-static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
-static DEFINE_MUTEX(cpu_scale_mutex);
 
-unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
-{
-       return per_cpu(cpu_scale, cpu);
-}
-
-static void set_capacity_scale(unsigned int cpu, unsigned long capacity)
-{
-       per_cpu(cpu_scale, cpu) = capacity;
-}
-
-static ssize_t cpu_capacity_show(struct device *dev,
-                                struct device_attribute *attr,
-                                char *buf)
-{
-       struct cpu *cpu = container_of(dev, struct cpu, dev);
-
-       return sprintf(buf, "%lu\n",
-                       arch_scale_cpu_capacity(NULL, cpu->dev.id));
-}
-
-static ssize_t cpu_capacity_store(struct device *dev,
-                                 struct device_attribute *attr,
-                                 const char *buf,
-                                 size_t count)
-{
-       struct cpu *cpu = container_of(dev, struct cpu, dev);
-       int this_cpu = cpu->dev.id, i;
-       unsigned long new_capacity;
-       ssize_t ret;
-
-       if (count) {
-               ret = kstrtoul(buf, 0, &new_capacity);
-               if (ret)
-                       return ret;
-               if (new_capacity > SCHED_CAPACITY_SCALE)
-                       return -EINVAL;
-
-               mutex_lock(&cpu_scale_mutex);
-               for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
-                       set_capacity_scale(i, new_capacity);
-               mutex_unlock(&cpu_scale_mutex);
-       }
-
-       return count;
-}
-
-static DEVICE_ATTR_RW(cpu_capacity);
-
-static int register_cpu_capacity_sysctl(void)
-{
-       int i;
-       struct device *cpu;
-
-       for_each_possible_cpu(i) {
-               cpu = get_cpu_device(i);
-               if (!cpu) {
-                       pr_err("%s: too early to get CPU%d device!\n",
-                              __func__, i);
-                       continue;
-               }
-               device_create_file(cpu, &dev_attr_cpu_capacity);
-       }
-
-       return 0;
-}
-subsys_initcall(register_cpu_capacity_sysctl);
+extern unsigned long
+arch_scale_cpu_capacity(struct sched_domain *sd, int cpu);
+extern void set_capacity_scale(unsigned int cpu, unsigned long capacity);
 
 #ifdef CONFIG_OF
 struct cpu_efficiency {
@@ -141,145 +76,9 @@ static unsigned long *__cpu_capacity;
 
 static unsigned long middle_capacity = 1;
 static bool cap_from_dt = true;
-static u32 *raw_capacity;
-static bool cap_parsing_failed;
-static u32 capacity_scale;
-
-static int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu)
-{
-       int ret = 1;
-       u32 cpu_capacity;
-
-       if (cap_parsing_failed)
-               return !ret;
-
-       ret = of_property_read_u32(cpu_node,
-                                  "capacity-dmips-mhz",
-                                  &cpu_capacity);
-       if (!ret) {
-               if (!raw_capacity) {
-                       raw_capacity = kcalloc(num_possible_cpus(),
-                                              sizeof(*raw_capacity),
-                                              GFP_KERNEL);
-                       if (!raw_capacity) {
-                               pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
-                               cap_parsing_failed = true;
-                               return 0;
-                       }
-               }
-               capacity_scale = max(cpu_capacity, capacity_scale);
-               raw_capacity[cpu] = cpu_capacity;
-               pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n",
-                       cpu_node->full_name, raw_capacity[cpu]);
-       } else {
-               if (raw_capacity) {
-                       pr_err("cpu_capacity: missing %s raw capacity\n",
-                               cpu_node->full_name);
-                       pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
-               }
-               cap_parsing_failed = true;
-               kfree(raw_capacity);
-       }
-
-       return !ret;
-}
-
-static void normalize_cpu_capacity(void)
-{
-       u64 capacity;
-       int cpu;
-
-       if (!raw_capacity || cap_parsing_failed)
-               return;
-
-       pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
-       mutex_lock(&cpu_scale_mutex);
-       for_each_possible_cpu(cpu) {
-               capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
-                       / capacity_scale;
-               set_capacity_scale(cpu, capacity);
-               pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
-                       cpu, arch_scale_cpu_capacity(NULL, cpu));
-       }
-       mutex_unlock(&cpu_scale_mutex);
-}
-
-#ifdef CONFIG_CPU_FREQ
-static cpumask_var_t cpus_to_visit;
-static bool cap_parsing_done;
-static void parsing_done_workfn(struct work_struct *work);
-static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
-
-static int
-init_cpu_capacity_callback(struct notifier_block *nb,
-                          unsigned long val,
-                          void *data)
-{
-       struct cpufreq_policy *policy = data;
-       int cpu;
-
-       if (cap_parsing_failed || cap_parsing_done)
-               return 0;
-
-       switch (val) {
-       case CPUFREQ_NOTIFY:
-               pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
-                               cpumask_pr_args(policy->related_cpus),
-                               cpumask_pr_args(cpus_to_visit));
-               cpumask_andnot(cpus_to_visit,
-                              cpus_to_visit,
-                              policy->related_cpus);
-               for_each_cpu(cpu, policy->related_cpus) {
-                       raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
-                                           policy->cpuinfo.max_freq / 1000UL;
-                       capacity_scale = max(raw_capacity[cpu], capacity_scale);
-               }
-               if (cpumask_empty(cpus_to_visit)) {
-                       normalize_cpu_capacity();
-                       kfree(raw_capacity);
-                       pr_debug("cpu_capacity: parsing done\n");
-                       cap_parsing_done = true;
-                       schedule_work(&parsing_done_work);
-               }
-       }
-       return 0;
-}
-
-static struct notifier_block init_cpu_capacity_notifier = {
-       .notifier_call = init_cpu_capacity_callback,
-};
-
-static int __init register_cpufreq_notifier(void)
-{
-       if (cap_parsing_failed)
-               return -EINVAL;
-
-       if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
-               pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
-               return -ENOMEM;
-       }
-       cpumask_copy(cpus_to_visit, cpu_possible_mask);
-
-       return cpufreq_register_notifier(&init_cpu_capacity_notifier,
-                                        CPUFREQ_POLICY_NOTIFIER);
-}
-core_initcall(register_cpufreq_notifier);
-
-static void parsing_done_workfn(struct work_struct *work)
-{
-       cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
-                                        CPUFREQ_POLICY_NOTIFIER);
-}
-
-#else
-static int __init free_raw_capacity(void)
-{
-       kfree(raw_capacity);
-
-       return 0;
-}
-core_initcall(free_raw_capacity);
-#endif
+extern bool cap_parsing_failed;
+extern void normalize_cpu_capacity(void);
+extern int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu);
 
 /*
  * Iterate all CPUs' descriptor in DT and compute the efficiency
index 3dcd7ec69bca8f939dba09e9087902fbd1561e8a..1ce760d259b67907f6a47601fdc627f45d86c95d 100644 (file)
@@ -41,6 +41,7 @@ config ARM64
        select EDAC_SUPPORT
        select FRAME_POINTER
        select GENERIC_ALLOCATOR
+       select GENERIC_ARCH_TOPOLOGY
        select GENERIC_CLOCKEVENTS
        select GENERIC_CLOCKEVENTS_BROADCAST
        select GENERIC_CPU_AUTOPROBE
index 08243533e5ee62e8454f129ea042437b2ee4aa39..c5bc31eb97e8103dd0c05ec624aa7f7c78de8f14 100644 (file)
@@ -11,7 +11,6 @@
  * for more details.
  */
 
-#include <linux/acpi.h>
 #include <linux/cpu.h>
 #include <linux/cpumask.h>
 #include <linux/init.h>
 #include <linux/sched/topology.h>
 #include <linux/slab.h>
 #include <linux/string.h>
-#include <linux/cpufreq.h>
 
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/topology.h>
 
-static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
-static DEFINE_MUTEX(cpu_scale_mutex);
-
-unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
-{
-       return per_cpu(cpu_scale, cpu);
-}
-
-static void set_capacity_scale(unsigned int cpu, unsigned long capacity)
-{
-       per_cpu(cpu_scale, cpu) = capacity;
-}
-
-static ssize_t cpu_capacity_show(struct device *dev,
-                                struct device_attribute *attr,
-                                char *buf)
-{
-       struct cpu *cpu = container_of(dev, struct cpu, dev);
-
-       return sprintf(buf, "%lu\n",
-                       arch_scale_cpu_capacity(NULL, cpu->dev.id));
-}
-
-static ssize_t cpu_capacity_store(struct device *dev,
-                                 struct device_attribute *attr,
-                                 const char *buf,
-                                 size_t count)
-{
-       struct cpu *cpu = container_of(dev, struct cpu, dev);
-       int this_cpu = cpu->dev.id, i;
-       unsigned long new_capacity;
-       ssize_t ret;
-
-       if (count) {
-               ret = kstrtoul(buf, 0, &new_capacity);
-               if (ret)
-                       return ret;
-               if (new_capacity > SCHED_CAPACITY_SCALE)
-                       return -EINVAL;
-
-               mutex_lock(&cpu_scale_mutex);
-               for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
-                       set_capacity_scale(i, new_capacity);
-               mutex_unlock(&cpu_scale_mutex);
-       }
-
-       return count;
-}
-
-static DEVICE_ATTR_RW(cpu_capacity);
-
-static int register_cpu_capacity_sysctl(void)
-{
-       int i;
-       struct device *cpu;
-
-       for_each_possible_cpu(i) {
-               cpu = get_cpu_device(i);
-               if (!cpu) {
-                       pr_err("%s: too early to get CPU%d device!\n",
-                              __func__, i);
-                       continue;
-               }
-               device_create_file(cpu, &dev_attr_cpu_capacity);
-       }
-
-       return 0;
-}
-subsys_initcall(register_cpu_capacity_sysctl);
-
-static u32 capacity_scale;
-static u32 *raw_capacity;
-static bool cap_parsing_failed;
-
-static void __init parse_cpu_capacity(struct device_node *cpu_node, int cpu)
-{
-       int ret;
-       u32 cpu_capacity;
-
-       if (cap_parsing_failed)
-               return;
-
-       ret = of_property_read_u32(cpu_node,
-                                  "capacity-dmips-mhz",
-                                  &cpu_capacity);
-       if (!ret) {
-               if (!raw_capacity) {
-                       raw_capacity = kcalloc(num_possible_cpus(),
-                                              sizeof(*raw_capacity),
-                                              GFP_KERNEL);
-                       if (!raw_capacity) {
-                               pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
-                               cap_parsing_failed = true;
-                               return;
-                       }
-               }
-               capacity_scale = max(cpu_capacity, capacity_scale);
-               raw_capacity[cpu] = cpu_capacity;
-               pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n",
-                       cpu_node->full_name, raw_capacity[cpu]);
-       } else {
-               if (raw_capacity) {
-                       pr_err("cpu_capacity: missing %s raw capacity\n",
-                               cpu_node->full_name);
-                       pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
-               }
-               cap_parsing_failed = true;
-               kfree(raw_capacity);
-       }
-}
-
-static void normalize_cpu_capacity(void)
-{
-       u64 capacity;
-       int cpu;
-
-       if (!raw_capacity || cap_parsing_failed)
-               return;
-
-       pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
-       mutex_lock(&cpu_scale_mutex);
-       for_each_possible_cpu(cpu) {
-               pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
-                        cpu, raw_capacity[cpu]);
-               capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
-                       / capacity_scale;
-               set_capacity_scale(cpu, capacity);
-               pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
-                       cpu, arch_scale_cpu_capacity(NULL, cpu));
-       }
-       mutex_unlock(&cpu_scale_mutex);
-}
-
-#ifdef CONFIG_CPU_FREQ
-static cpumask_var_t cpus_to_visit;
-static bool cap_parsing_done;
-static void parsing_done_workfn(struct work_struct *work);
-static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
-
-static int
-init_cpu_capacity_callback(struct notifier_block *nb,
-                          unsigned long val,
-                          void *data)
-{
-       struct cpufreq_policy *policy = data;
-       int cpu;
-
-       if (cap_parsing_failed || cap_parsing_done)
-               return 0;
-
-       switch (val) {
-       case CPUFREQ_NOTIFY:
-               pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
-                               cpumask_pr_args(policy->related_cpus),
-                               cpumask_pr_args(cpus_to_visit));
-               cpumask_andnot(cpus_to_visit,
-                              cpus_to_visit,
-                              policy->related_cpus);
-               for_each_cpu(cpu, policy->related_cpus) {
-                       raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
-                                           policy->cpuinfo.max_freq / 1000UL;
-                       capacity_scale = max(raw_capacity[cpu], capacity_scale);
-               }
-               if (cpumask_empty(cpus_to_visit)) {
-                       normalize_cpu_capacity();
-                       kfree(raw_capacity);
-                       pr_debug("cpu_capacity: parsing done\n");
-                       cap_parsing_done = true;
-                       schedule_work(&parsing_done_work);
-               }
-       }
-       return 0;
-}
-
-static struct notifier_block init_cpu_capacity_notifier = {
-       .notifier_call = init_cpu_capacity_callback,
-};
-
-static int __init register_cpufreq_notifier(void)
-{
-       /*
-        * on ACPI-based systems we need to use the default cpu capacity
-        * until we have the necessary code to parse the cpu capacity, so
-        * skip registering cpufreq notifier.
-        */
-       if (!acpi_disabled || cap_parsing_failed)
-               return -EINVAL;
-
-       if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
-               pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
-               return -ENOMEM;
-       }
-       cpumask_copy(cpus_to_visit, cpu_possible_mask);
-
-       return cpufreq_register_notifier(&init_cpu_capacity_notifier,
-                                        CPUFREQ_POLICY_NOTIFIER);
-}
-core_initcall(register_cpufreq_notifier);
-
-static void parsing_done_workfn(struct work_struct *work)
-{
-       cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
-                                        CPUFREQ_POLICY_NOTIFIER);
-}
-
-#else
-static int __init free_raw_capacity(void)
-{
-       kfree(raw_capacity);
-
-       return 0;
-}
-core_initcall(free_raw_capacity);
-#endif
+extern bool cap_parsing_failed;
+extern void normalize_cpu_capacity(void);
+extern int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu);
 
 static int __init get_cpu_for_node(struct device_node *node)
 {
index d718ae4b907a37d8958077457fa8a634c6d2e192..f046d21de57dd956819ad4227535667a0b74cbe9 100644 (file)
@@ -339,4 +339,12 @@ config CMA_ALIGNMENT
 
 endif
 
+config GENERIC_ARCH_TOPOLOGY
+       bool
+       help
+         Enable support for architectures common topology code: e.g., parsing
+         CPU capacity information from DT, usage of such information for
+         appropriate scaling, sysfs interface for changing capacity values at
+         runtime.
+
 endmenu
index f2816f6ff76af4e3b864432af60a7a2e14259021..397e5c344e6a982c493cd1e5d073089510e2a748 100644 (file)
@@ -23,6 +23,7 @@ obj-$(CONFIG_SOC_BUS) += soc.o
 obj-$(CONFIG_PINCTRL) += pinctrl.o
 obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
 obj-$(CONFIG_GENERIC_MSI_IRQ_DOMAIN) += platform-msi.o
+obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o
 
 obj-y                  += test/
 
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
new file mode 100644 (file)
index 0000000..097834f
--- /dev/null
@@ -0,0 +1,242 @@
+/*
+ * Arch specific cpu topology information
+ *
+ * Copyright (C) 2016, ARM Ltd.
+ * Written by: Juri Lelli, ARM Ltd.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Released under the GPLv2 only.
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <linux/acpi.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/sched/topology.h>
+
+static DEFINE_MUTEX(cpu_scale_mutex);
+static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
+
+unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
+{
+       return per_cpu(cpu_scale, cpu);
+}
+
+void set_capacity_scale(unsigned int cpu, unsigned long capacity)
+{
+       per_cpu(cpu_scale, cpu) = capacity;
+}
+
+static ssize_t cpu_capacity_show(struct device *dev,
+                                struct device_attribute *attr,
+                                char *buf)
+{
+       struct cpu *cpu = container_of(dev, struct cpu, dev);
+
+       return sprintf(buf, "%lu\n",
+                       arch_scale_cpu_capacity(NULL, cpu->dev.id));
+}
+
+static ssize_t cpu_capacity_store(struct device *dev,
+                                 struct device_attribute *attr,
+                                 const char *buf,
+                                 size_t count)
+{
+       struct cpu *cpu = container_of(dev, struct cpu, dev);
+       int this_cpu = cpu->dev.id;
+       int i;
+       unsigned long new_capacity;
+       ssize_t ret;
+
+       if (!count)
+               return 0;
+
+       ret = kstrtoul(buf, 0, &new_capacity);
+       if (ret)
+               return ret;
+       if (new_capacity > SCHED_CAPACITY_SCALE)
+               return -EINVAL;
+
+       mutex_lock(&cpu_scale_mutex);
+       for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
+               set_capacity_scale(i, new_capacity);
+       mutex_unlock(&cpu_scale_mutex);
+
+       return count;
+}
+
+static DEVICE_ATTR_RW(cpu_capacity);
+
+static int register_cpu_capacity_sysctl(void)
+{
+       int i;
+       struct device *cpu;
+
+       for_each_possible_cpu(i) {
+               cpu = get_cpu_device(i);
+               if (!cpu) {
+                       pr_err("%s: too early to get CPU%d device!\n",
+                              __func__, i);
+                       continue;
+               }
+               device_create_file(cpu, &dev_attr_cpu_capacity);
+       }
+
+       return 0;
+}
+subsys_initcall(register_cpu_capacity_sysctl);
+
+static u32 capacity_scale;
+static u32 *raw_capacity;
+bool cap_parsing_failed;
+
+void normalize_cpu_capacity(void)
+{
+       u64 capacity;
+       int cpu;
+
+       if (!raw_capacity || cap_parsing_failed)
+               return;
+
+       pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
+       mutex_lock(&cpu_scale_mutex);
+       for_each_possible_cpu(cpu) {
+               pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
+                        cpu, raw_capacity[cpu]);
+               capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
+                       / capacity_scale;
+               set_capacity_scale(cpu, capacity);
+               pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
+                       cpu, arch_scale_cpu_capacity(NULL, cpu));
+       }
+       mutex_unlock(&cpu_scale_mutex);
+}
+
+int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu)
+{
+       int ret = 1;
+       u32 cpu_capacity;
+
+       if (cap_parsing_failed)
+               return !ret;
+
+       ret = of_property_read_u32(cpu_node,
+                                  "capacity-dmips-mhz",
+                                  &cpu_capacity);
+       if (!ret) {
+               if (!raw_capacity) {
+                       raw_capacity = kcalloc(num_possible_cpus(),
+                                              sizeof(*raw_capacity),
+                                              GFP_KERNEL);
+                       if (!raw_capacity) {
+                               pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
+                               cap_parsing_failed = true;
+                               return 0;
+                       }
+               }
+               capacity_scale = max(cpu_capacity, capacity_scale);
+               raw_capacity[cpu] = cpu_capacity;
+               pr_debug("cpu_capacity: %s cpu_capacity=%u (raw)\n",
+                       cpu_node->full_name, raw_capacity[cpu]);
+       } else {
+               if (raw_capacity) {
+                       pr_err("cpu_capacity: missing %s raw capacity\n",
+                               cpu_node->full_name);
+                       pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
+               }
+               cap_parsing_failed = true;
+               kfree(raw_capacity);
+       }
+
+       return !ret;
+}
+
+#ifdef CONFIG_CPU_FREQ
+static cpumask_var_t cpus_to_visit;
+static bool cap_parsing_done;
+static void parsing_done_workfn(struct work_struct *work);
+static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
+
+static int
+init_cpu_capacity_callback(struct notifier_block *nb,
+                          unsigned long val,
+                          void *data)
+{
+       struct cpufreq_policy *policy = data;
+       int cpu;
+
+       if (cap_parsing_failed || cap_parsing_done)
+               return 0;
+
+       switch (val) {
+       case CPUFREQ_NOTIFY:
+               pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
+                               cpumask_pr_args(policy->related_cpus),
+                               cpumask_pr_args(cpus_to_visit));
+               cpumask_andnot(cpus_to_visit,
+                              cpus_to_visit,
+                              policy->related_cpus);
+               for_each_cpu(cpu, policy->related_cpus) {
+                       raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
+                                           policy->cpuinfo.max_freq / 1000UL;
+                       capacity_scale = max(raw_capacity[cpu], capacity_scale);
+               }
+               if (cpumask_empty(cpus_to_visit)) {
+                       normalize_cpu_capacity();
+                       kfree(raw_capacity);
+                       pr_debug("cpu_capacity: parsing done\n");
+                       cap_parsing_done = true;
+                       schedule_work(&parsing_done_work);
+               }
+       }
+       return 0;
+}
+
+static struct notifier_block init_cpu_capacity_notifier = {
+       .notifier_call = init_cpu_capacity_callback,
+};
+
+static int __init register_cpufreq_notifier(void)
+{
+       /*
+        * on ACPI-based systems we need to use the default cpu capacity
+        * until we have the necessary code to parse the cpu capacity, so
+        * skip registering cpufreq notifier.
+        */
+       if (!acpi_disabled || cap_parsing_failed)
+               return -EINVAL;
+
+       if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
+               pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
+               return -ENOMEM;
+       }
+
+       cpumask_copy(cpus_to_visit, cpu_possible_mask);
+
+       return cpufreq_register_notifier(&init_cpu_capacity_notifier,
+                                        CPUFREQ_POLICY_NOTIFIER);
+}
+core_initcall(register_cpufreq_notifier);
+
+static void parsing_done_workfn(struct work_struct *work)
+{
+       cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
+                                        CPUFREQ_POLICY_NOTIFIER);
+}
+
+#else
+static int __init free_raw_capacity(void)
+{
+       kfree(raw_capacity);
+
+       return 0;
+}
+core_initcall(free_raw_capacity);
+#endif