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    SubjectRe: [PATCH 1/6] cpufreq: Add debugfs directory for cpufreq
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    Hi Chanwoo,

    On Fri, Jul 5, 2013 at 1:46 AM, Chanwoo Choi <cw00.choi@samsung.com> wrote:
    > 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 CPU(except for CPU0) create
    > a link for debugfs directory of CPU0.
    > - /sys/kernel/debug/cpufreq/cpu0
    > - /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 <cw00.choi@samsung.com>
    > Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
    > Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>
    > ---
    > drivers/cpufreq/cpufreq.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++
    > include/linux/cpufreq.h | 1 +
    > 2 files changed, 58 insertions(+)
    >
    > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
    > index 2d53f47..bc01c8e 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>
    > @@ -47,6 +48,10 @@ static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
    > #endif
    > static DEFINE_RWLOCK(cpufreq_driver_lock);
    >
    > +/* The cpufreq_debugfs is used to create debugfs root directory for CPUFreq. */
    > +#define MAX_DEBUGFS_NAME_LEN CPUFREQ_NAME_LEN
    > +static struct dentry *cpufreq_debugfs;
    > +
    > /*
    > * cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
    > * all cpufreq/hotplug/workqueue/etc related lock issues.
    > @@ -726,6 +731,20 @@ static int cpufreq_add_dev_symlink(unsigned int cpu,
    > cpufreq_cpu_put(managed_policy);
    > return ret;
    > }
    > +
    > + if (cpufreq_debugfs) {
    > + char symlink_name[MAX_DEBUGFS_NAME_LEN];
    > + char target_name[MAX_DEBUGFS_NAME_LEN];
    > +
    > + sprintf(symlink_name, "cpu%d", j);
    > + sprintf(target_name, "./cpu%d", cpu);
    > + managed_policy->cpu_debugfs[j] = debugfs_create_symlink(
    > + symlink_name,
    > + cpufreq_debugfs,
    > + target_name);
    > + if (!managed_policy->cpu_debugfs[j])
    > + pr_debug("creating debugfs symlink failed\n");
    > + }
    > }
    > return ret;
    > }
    > @@ -746,6 +765,22 @@ static int cpufreq_add_dev_interface(unsigned int cpu,
    > if (ret)
    > return ret;
    >
    > + /* prepare interface data for debugfs */
    > + if (cpufreq_debugfs) {
    > + char name[MAX_DEBUGFS_NAME_LEN];
    > + int size, i;
    > +
    > + sprintf(name, "cpu%d", policy->cpu);
    > + size = sizeof(struct dentry*) * NR_CPUS;
    > + i = cpu;
    > +
    > + policy->cpu_debugfs = devm_kzalloc(dev, size, GFP_KERNEL);
    > + policy->cpu_debugfs[i] = debugfs_create_dir(name,
    > + cpufreq_debugfs);
    > + if (!policy->cpu_debugfs[i])
    > + pr_debug("creating debugfs directory failed\n");
    > + }
    > +
    > /* set up files for this cpu device */
    > drv_attr = cpufreq_driver->attr;
    > while ((drv_attr) && (*drv_attr)) {
    > @@ -839,6 +874,20 @@ static int cpufreq_add_policy_cpu(unsigned int cpu, unsigned int sibling,
    > return ret;
    > }
    >
    > + if (cpufreq_debugfs) {
    > + char symlink_name[MAX_DEBUGFS_NAME_LEN];
    > + char target_name[MAX_DEBUGFS_NAME_LEN];
    > +
    > + sprintf(symlink_name, "cpu%d", cpu);
    > + sprintf(target_name, "./cpu%d", sibling);
    > + policy->cpu_debugfs[cpu] = debugfs_create_symlink(
    > + symlink_name,
    > + cpufreq_debugfs,
    > + target_name);
    > + if (!policy->cpu_debugfs[cpu])
    > + pr_debug("creating debugfs symlink failed\n");
    > + }
    > +
    > return 0;
    > }
    > #endif
    > @@ -1046,6 +1095,7 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif
    >
    > if (cpu != data->cpu) {
    > sysfs_remove_link(&dev->kobj, "cpufreq");
    > + debugfs_remove(data->cpu_debugfs[cpu]);

    I think you should add the call to remove the "cpufreq" also ???
    "debugfs_remove(cpufreq_debugfs);"
    > } else if (cpus > 1) {
    > /* first sibling now owns the new sysfs dir */
    > cpu_dev = get_cpu_device(cpumask_first(data->cpus));
    > @@ -1068,6 +1118,9 @@ static int __cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif
    > return -EINVAL;
    > }
    >
    > + debugfs_remove_recursive(data->cpu_debugfs[cpu]);
    > + debugfs_remove(cpufreq_debugfs);
    > +
    > WARN_ON(lock_policy_rwsem_write(cpu));
    > update_policy_cpu(data, cpu_dev->id);
    > unlock_policy_rwsem_write(cpu);
    > @@ -1976,6 +2029,10 @@ static int __init cpufreq_core_init(void)
    > BUG_ON(!cpufreq_global_kobject);
    > register_syscore_ops(&cpufreq_syscore_ops);
    >
    > + cpufreq_debugfs = debugfs_create_dir("cpufreq", NULL);
    > + if (!cpufreq_debugfs)
    > + pr_debug("creating debugfs root failed\n");
    > +
    > return 0;
    > }
    > core_initcall(cpufreq_core_init);
    > 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-pm" in
    > the body of a message to majordomo@vger.kernel.org
    > More majordomo info at http://vger.kernel.org/majordomo-info.html

    Regards,
    Pankaj Jangra


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