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) Signed-off-by: Chanwoo Choi <[email protected]> Signed-off-by: Kyungmin Park <[email protected]> Signed-off-by: Myungjoo Ham <[email protected]> --- 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) drivers/cpufreq/cpufreq.c | 177 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/cpufreq.h | 1 + 2 files changed, 178 insertions(+) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 2d53f47..924d654 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -23,6 +23,7 @@ #include <linux/notifier.h> #include <linux/cpufreq.h> #include <linux/delay.h> +#include <linux/debugfs.h> #include <linux/interrupt.h> #include <linux/spinlock.h> #include <linux/device.h> @@ -703,6 +704,164 @@ static struct kobj_type ktype_cpufreq = { .release = cpufreq_sysfs_release, }; +#ifdef CONFIG_CPU_FREQ_STAT +/* The cpufreq_debugfs is used to create debugfs root directory for CPUFreq. */ +static struct dentry *cpufreq_debugfs; + +static int cpufreq_create_debugfs_dir(struct cpufreq_policy *policy, + struct device *dev) +{ + char name[CPUFREQ_NAME_LEN]; + unsigned int cpus, size, idx; + + if (!cpufreq_debugfs) + return -EINVAL; + + cpus = cpumask_weight(policy->cpus); + idx = cpus > 1 ? policy->cpu : 0; + + size = sizeof(struct dentry*) * cpus; + policy->cpu_debugfs = devm_kzalloc(dev, size, GFP_KERNEL); + if (!policy->cpu_debugfs) { + pr_err("allocating debugfs memory failed\n"); + return -ENOMEM; + } + + 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(struct cpufreq_policy *policy, + unsigned int src_cpu, + unsigned int dest_cpu) +{ + char symlink_name[CPUFREQ_NAME_LEN]; + char target_name[CPUFREQ_NAME_LEN]; + + if (!cpufreq_debugfs) + return -EINVAL; + + if (!policy->cpu_debugfs[src_cpu]) + return -EINVAL; + + sprintf(symlink_name, "cpu%d", dest_cpu); + sprintf(target_name, "./cpu%d", src_cpu); + policy->cpu_debugfs[dest_cpu] = debugfs_create_symlink( + symlink_name, + cpufreq_debugfs, + target_name); + if (!policy->cpu_debugfs[dest_cpu]) { + pr_err("creating debugfs symlink failed\n"); + return -ENODEV; + } + + return 0; +} + +static void cpufreq_remove_debugfs_dir(struct cpufreq_policy *policy, + unsigned int cpu) +{ + unsigned int idx = cpumask_weight(policy->cpus) > 1 ? cpu : 0; + + if (!policy->cpu_debugfs[idx]) + return; + + debugfs_remove_recursive(policy->cpu_debugfs[idx]); +} + +static void cpufreq_move_debugfs_dir(struct cpufreq_policy *policy, + unsigned int new_cpu) +{ + struct dentry *old_entry, *new_entry; + char new_dir_name[CPUFREQ_NAME_LEN]; + unsigned int j, old_cpu = policy->cpu; + + if (!policy->cpu_debugfs[new_cpu]) + return; + + /* + * Remove symbolic link of debugfs directory except for debugfs + * directory of old_cpu. + */ + for_each_present_cpu(j) { + if (old_cpu == j) + continue; + + debugfs_remove(policy->cpu_debugfs[j]); + } + + /* + * Change debugfs directory name from as following: + * - old debugfs dir name : /sys/kernel/debugfs/cpufreq/cpu${old_cpu} + * - new debugfs dir name : /sys/kernel/debugfs/cpufreq/cpu${new_cpu} + */ + sprintf(new_dir_name, "cpu%d", new_cpu); + old_entry = policy->cpu_debugfs[old_cpu]; + new_entry = debugfs_rename(cpufreq_debugfs, old_entry, + cpufreq_debugfs, new_dir_name); + if (!new_entry) { + pr_err("changing debugfs directory name failed\n"); + goto err_rename; + } + + policy->cpu_debugfs[new_cpu] = new_entry; + policy->cpu_debugfs[old_cpu] = NULL; + + /* Create again symbolic link of debugfs directory */ + for_each_present_cpu(j) { + if (new_cpu == j) + continue; + + cpufreq_create_debugfs_symlink(policy, new_cpu, j); + } + + return; + +err_rename: + for_each_present_cpu(j) { + if (old_cpu == j) + continue; + + cpufreq_create_debugfs_symlink(policy, old_cpu, j); + } +} + +static int cpufreq_create_debugfs(void) +{ + cpufreq_debugfs = debugfs_create_dir("cpufreq", NULL); + if (!cpufreq_debugfs) { + pr_err("creating debugfs root failed\n"); + return -ENODEV; + } + + return 0; +} + +static void cpufreq_remove_debugfs(void) +{ + if (cpufreq_debugfs) + debugfs_remove_recursive(cpufreq_debugfs); +} +#else +static int cpufreq_create_debugfs_dir(struct cpufreq_policy *policy, + struct device *dev) { return 0; } +static int cpufreq_create_debugfs_symlink(struct cpufreq_policy *policy, + unsigned int src_cpu, + unsigned int dest_cpu) { return 0;} +static void cpufreq_remove_debugfs_dir(struct cpufreq_policy *policy, + unsigned int cpu) { } +static void cpufreq_move_debugfs_dir(struct cpufreq_policy *policy, + unsigned int new_cpu) { } +static int cpufreq_create_debugfs(void) { return 0; } +static void cpufreq_remove_debugfs(void) { } +#endif + /* symlink affected CPUs */ static int cpufreq_add_dev_symlink(unsigned int cpu, struct cpufreq_policy *policy) @@ -726,6 +885,8 @@ static int cpufreq_add_dev_symlink(unsigned int cpu, cpufreq_cpu_put(managed_policy); return ret; } + + cpufreq_create_debugfs_symlink(policy, cpu, j); } return ret; } @@ -777,6 +938,9 @@ 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(policy, dev); + ret = cpufreq_add_dev_symlink(cpu, policy); if (ret) goto err_out_kobj_put; @@ -839,6 +1003,8 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling, return ret; } + cpufreq_create_debugfs_symlink(policy, sibling, cpu); + return 0; } #endif @@ -1046,6 +1212,7 @@ 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_dir(data, cpu); } else if (cpus > 1) { /* first sibling now owns the new sysfs dir */ cpu_dev = get_cpu_device(cpumask_first(data->cpus)); @@ -1068,6 +1235,8 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif return -EINVAL; } + cpufreq_move_debugfs_dir(data, cpu_dev->id); + WARN_ON(lock_policy_rwsem_write(cpu)); update_policy_cpu(data, cpu_dev->id); unlock_policy_rwsem_write(cpu); @@ -1089,6 +1258,8 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif unlock_policy_rwsem_read(cpu); kobject_put(kobj); + cpufreq_remove_debugfs_dir(data, cpu); + /* we need to make sure that the underlying kobj is actually * not referenced anymore by anybody before we proceed with * unloading. @@ -1894,6 +2065,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) cpufreq_driver = driver_data; write_unlock_irqrestore(&cpufreq_driver_lock, flags); + cpufreq_create_debugfs(); + ret = subsys_interface_register(&cpufreq_interface); if (ret) goto err_null_driver; @@ -1918,12 +2091,14 @@ 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; err_if_unreg: subsys_interface_unregister(&cpufreq_interface); err_null_driver: + cpufreq_remove_debugfs(); write_lock_irqsave(&cpufreq_driver_lock, flags); cpufreq_driver = NULL; write_unlock_irqrestore(&cpufreq_driver_lock, flags); @@ -1949,6 +2124,8 @@ int cpufreq_unregister_driver(struct cpufreq_driver *driver) pr_debug("unregistering driver %s\n", driver->name); + cpufreq_remove_debugfs(); + subsys_interface_unregister(&cpufreq_interface); unregister_hotcpu_notifier(&cpufreq_cpu_notifier); diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 037d36a..825f379 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -115,6 +115,7 @@ struct cpufreq_policy { struct kobject kobj; struct completion kobj_unregister; + struct dentry **cpu_debugfs; }; #define CPUFREQ_ADJUST (0) -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
