From 4d33113bfe2c9e2fd1484065b82abefdf759bf49 Mon Sep 17 00:00:00 2001 From: Chanwoo Choi Date: Tue, 19 Aug 2014 15:43:52 +0900 Subject: [PATCH] cpufreq: Add debugfs directory for cpufreq This patch create debugfs root directory and child directory according to the number of CPUs for CPUFreq as below debugfs directory path: - /sys/kernel/debug/cpufreq/cpuX If many CPUs share only one cpufreq policy, other CPUs(except for first CPU) create a symbolic link for debugfs directory of CPU0. - link: /sys/kernel/debug/cpufreq/cpu[1-(N-1)] -> /sys/kernel/debug/cpufreq/cpu0 And then cpufreq may need to create debugfs specific file below of debugfs directory of cpufreq. (e.g., /sys/kernel/debug/cpufreq/cpu0/load_table) Changes since v6: - Use 'policy->related_cpus' instead of 'policy->cpus' when getting the number of CPUs included in the same package - Get correct index of cpu_debugfs[] array according to cpu number - Refactoring cpufreq_move_debugfs_dir() / cpufreq_create_debugfs_symlink() - Use for_each_cpu() to support multi cluster instead of for_each_present_cpu() Changes since v5: - Refactoring patch v4 - Create again symbolic link of debugfs directory when first CPU dev is removed (In this case, many CPUs share only one cpufreq policy) Change-Id: Ibd84118e6dd3b1e3bc624e1871d39425c99b1673 Signed-off-by: Chanwoo Choi Signed-off-by: Kyungmin Park --- drivers/cpufreq/cpufreq.c | 178 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/cpufreq.h | 2 + 2 files changed, 180 insertions(+) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 12d50e8..0535b56 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -784,6 +785,170 @@ void cpufreq_sysfs_remove_file(const struct attribute *attr) } EXPORT_SYMBOL(cpufreq_sysfs_remove_file); +#ifdef CONFIG_CPU_FREQ_STAT +/* The cpufreq_debugfs is used to create debugfs root directory for CPUFreq */ +static struct dentry *cpufreq_debugfs; + +static unsigned int cpufreq_get_index(unsigned int cpu, + struct cpufreq_policy *policy) +{ + unsigned int j, idx = 0; + + for_each_cpu(j, policy->related_cpus) { + if (j == cpu) + break; + idx++; + } + + return idx; +} + +static int cpufreq_create_debugfs_dir(unsigned int cpu, + struct cpufreq_policy *policy) +{ + struct device *cpu_dev; + unsigned int cpus, size, idx = 0; + char name[CPUFREQ_NAME_LEN]; + + if (!cpufreq_debugfs) + return -EINVAL; + + cpus = cpumask_weight(policy->related_cpus); + + size = sizeof(struct dentry*) * cpus; + cpu_dev = get_cpu_device(cpu); + policy->cpu_debugfs = devm_kzalloc(cpu_dev, size, GFP_KERNEL); + if (!policy->cpu_debugfs) { + pr_err("allocating debugfs memory failed\n"); + return -ENOMEM; + } + + idx = cpufreq_get_index(policy->cpu, policy); + + sprintf(name, "cpu%d", policy->cpu); + policy->cpu_debugfs[idx] = debugfs_create_dir(name, cpufreq_debugfs); + if (!policy->cpu_debugfs[idx]) { + pr_err("creating debugfs directory failed\n"); + return -ENODEV; + } + + return 0; +} + +static int cpufreq_create_debugfs_symlink(unsigned int cpu, + struct cpufreq_policy *policy) +{ + char symlink_name[CPUFREQ_NAME_LEN]; + char target_name[CPUFREQ_NAME_LEN]; + unsigned int idx; + + if (!cpufreq_debugfs) + return -EINVAL; + + idx = cpufreq_get_index(cpu, policy); + if (policy->cpu_debugfs[idx]) + return -EINVAL; + + sprintf(target_name, "./cpu%d", policy->cpu); + sprintf(symlink_name, "cpu%d", cpu); + policy->cpu_debugfs[idx] = debugfs_create_symlink(symlink_name, + cpufreq_debugfs, + target_name); + if (!policy->cpu_debugfs[idx]) { + pr_err("creating debugfs symlink failed\n"); + return -ENODEV; + } + + return 0; +} + +static void cpufreq_remove_debugfs(unsigned int cpu, + struct cpufreq_policy *policy) +{ + unsigned int idx = cpufreq_get_index(cpu, policy); + + if (!policy->cpu_debugfs[idx]) + return; + + if (cpu == policy->cpu) + debugfs_remove_recursive(policy->cpu_debugfs[idx]); + else + debugfs_remove(policy->cpu_debugfs[idx]); + + policy->cpu_debugfs[idx] = NULL; +} + +static int cpufreq_move_debugfs_dir(unsigned int cpu, + struct cpufreq_policy *policy) +{ + struct dentry *new_entry; + char new_dir_name[CPUFREQ_NAME_LEN]; + unsigned int new_cpu_idx, old_cpu_idx, sibling; + + new_cpu_idx = cpufreq_get_index(cpu, policy); + if (!policy->cpu_debugfs[new_cpu_idx]) + return -EINVAL; + + /* + * Delete previous symbolic link of debugfs directory for new cpu. + * The target of debugfs_rename() must not exist for rename to succedd. + */ + cpufreq_remove_debugfs(cpu, policy); + + /* Change debugfs directory name from old_cpu to new_cpu */ + old_cpu_idx = cpufreq_get_index(policy->cpu, policy); + sprintf(new_dir_name, "cpu%d", cpu); + new_entry = debugfs_rename(cpufreq_debugfs, + policy->cpu_debugfs[old_cpu_idx], + cpufreq_debugfs, + new_dir_name); + if (!policy->cpu_debugfs[new_cpu_idx]) { + pr_err("changing debugfs directory name failed\n"); + return -EINVAL; + } + policy->cpu_debugfs[new_cpu_idx] = new_entry; + policy->cpu_debugfs[old_cpu_idx] = NULL; + + /* Create again symbolic link of debugfs directory for online CPUs */ + for_each_cpu(sibling, policy->cpus) { + if (cpu == sibling || policy->cpu == sibling) + continue; + + cpufreq_remove_debugfs(sibling, policy); + cpufreq_create_debugfs_symlink(sibling, policy); + } + + return 0; +} + +static void cpufreq_init_debugfs(void) +{ + cpufreq_debugfs = debugfs_create_dir("cpufreq", NULL); + if (!cpufreq_debugfs) { + pr_err("creating debugfs root failed\n"); + } +} +#else +static inline int cpufreq_create_debugfs_dir(unsigned int cpu, + struct cpufreq_policy *policy) +{ + return 0; +} +static inline int cpufreq_create_debugfs_symlink(unsigned int cpu, + struct cpufreq_policy *policy) +{ + return 0; +} +static inline int cpufreq_move_debugfs_dir(unsigned int cpu, + struct cpufreq_policy *policy) +{ + return 0; +} +static inline void cpufreq_remove_debugfs(unsigned int cpu, + struct cpufreq_policy *policy) { } +static inline void cpufreq_init_debugfs(void) { } +#endif /* CONFIG_CPU_FREQ_STAT */ + /* symlink affected CPUs */ static int cpufreq_add_dev_symlink(unsigned int cpu, struct cpufreq_policy *policy) @@ -807,6 +972,8 @@ static int cpufreq_add_dev_symlink(unsigned int cpu, cpufreq_cpu_put(managed_policy); return ret; } + + cpufreq_create_debugfs_symlink(j, policy); } return ret; } @@ -858,6 +1025,9 @@ static int cpufreq_add_dev_interface(unsigned int cpu, } write_unlock_irqrestore(&cpufreq_driver_lock, flags); + /* prepare interface data for debugfs */ + cpufreq_create_debugfs_dir(cpu, policy); + ret = cpufreq_add_dev_symlink(cpu, policy); if (ret) goto err_out_kobj_put; @@ -914,6 +1084,8 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); } + cpufreq_create_debugfs_symlink(cpu, policy); + ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq"); if (ret) { cpufreq_cpu_put(policy); @@ -1128,6 +1300,7 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif if (cpu != data->cpu) { sysfs_remove_link(&dev->kobj, "cpufreq"); + cpufreq_remove_debugfs(cpu, data); } else if (cpus > 1) { /* first sibling now owns the new sysfs dir */ cpu_dev = get_cpu_device(cpumask_first(data->cpus)); @@ -1152,6 +1325,7 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif WARN_ON(lock_policy_rwsem_write(cpu)); update_policy_cpu(data, cpu_dev->id); + cpufreq_move_debugfs_dir(cpu_dev->id, data); unlock_policy_rwsem_write(cpu); pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n", __func__, cpu_dev->id, cpu); @@ -1168,6 +1342,8 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif unlock_policy_rwsem_read(cpu); kobject_put(kobj); + cpufreq_remove_debugfs(cpu, data); + /* we need to make sure that the underlying kobj is actually * not referenced anymore by anybody before we proceed with * unloading. @@ -2103,6 +2279,7 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) } register_hotcpu_notifier(&cpufreq_cpu_notifier); + pr_debug("driver %s up and running\n", driver_data->name); return 0; @@ -2165,6 +2342,7 @@ static int __init cpufreq_core_init(void) cpufreq_global_kobject = kobject_create(); BUG_ON(!cpufreq_global_kobject); + cpufreq_init_debugfs(); register_syscore_ops(&cpufreq_syscore_ops); return 0; diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 940f1fe..d8f40a1 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -123,6 +123,8 @@ struct cpufreq_policy { struct kobject kobj; struct completion kobj_unregister; int transition_ongoing; /* Tracks transition status */ + + struct dentry **cpu_debugfs; }; #define CPUFREQ_ADJUST (0) -- 2.7.4