PM / devfreq: Add debugfs support with devfreq_summary file

Add debugfs interface to provide debugging information of devfreq device.
It contains 'devfreq_summary' entry to show the summary of registered
devfreq devices as following and the additional debugfs file will be added.
- /sys/kernel/debug/devfreq/devfreq_summary

[Detailed description of each field of 'devfreq_summary' debugfs file]
- dev_name	: Device name of h/w
- dev		: Device name made by devfreq core
- parent_dev	: If devfreq device uses the passive governor,
		  show parent devfreq device name. Otherwise, show 'null'.
- governor	: Devfreq governor name
- polling_ms	: If devfreq device uses the simple_ondemand governor,
		  polling_ms is necessary for the period. (unit: millisecond)
- cur_freq_Hz	: Current frequency (unit: Hz)
- min_freq_Hz	: Minimum frequency (unit: Hz)
- max_freq_Hz	: Maximum frequency (unit: Hz)

[For example on Exynos5422-based Odroid-XU3 board]
$ cat /sys/kernel/debug/devfreq/devfreq_summary
dev_name                       dev        parent_dev governor        polling_ms  cur_freq_Hz  min_freq_Hz  max_freq_Hz
------------------------------ ---------- ---------- --------------- ---------- ------------ ------------ ------------
10c20000.memory-controller     devfreq0   null       simple_ondemand          0    165000000    165000000    825000000
soc:bus_wcore                  devfreq1   null       simple_ondemand         50    532000000     88700000    532000000
soc:bus_noc                    devfreq2   devfreq1   passive                  0    111000000     66600000    111000000
soc:bus_fsys_apb               devfreq3   devfreq1   passive                  0    222000000    111000000    222000000
soc:bus_fsys                   devfreq4   devfreq1   passive                  0    200000000     75000000    200000000
soc:bus_fsys2                  devfreq5   devfreq1   passive                  0    200000000     75000000    200000000
soc:bus_mfc                    devfreq6   devfreq1   passive                  0    333000000     83250000    333000000
soc:bus_gen                    devfreq7   devfreq1   passive                  0    266000000     88700000    266000000
soc:bus_peri                   devfreq8   devfreq1   passive                  0     66600000     66600000     66600000
soc:bus_g2d                    devfreq9   devfreq1   passive                  0    333000000     83250000    333000000
soc:bus_g2d_acp                devfreq10  devfreq1   passive                  0    266000000     66500000    266000000
soc:bus_jpeg                   devfreq11  devfreq1   passive                  0    300000000     75000000    300000000
soc:bus_jpeg_apb               devfreq12  devfreq1   passive                  0    166500000     83250000    166500000
soc:bus_disp1_fimd             devfreq13  devfreq1   passive                  0    200000000    120000000    200000000
soc:bus_disp1                  devfreq14  devfreq1   passive                  0    300000000    120000000    300000000
soc:bus_gscl_scaler            devfreq15  devfreq1   passive                  0    300000000    150000000    300000000
soc:bus_mscl                   devfreq16  devfreq1   passive                  0    666000000     84000000    666000000

[lkp: Reported the build error]
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 89260b1..cceee8b 100644 (file)
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -10,6 +10,7 @@
 #include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/sched.h>
+#include <linux/debugfs.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/init.h>
@@ -33,6 +34,7 @@
 #define HZ_PER_KHZ     1000
 
 static struct class *devfreq_class;
+static struct dentry *devfreq_debugfs;
 
 /*
  * devfreq core provides delayed work based load monitoring helper
@@ -1643,6 +1645,81 @@ static struct attribute *devfreq_attrs[] = {
 };
 ATTRIBUTE_GROUPS(devfreq);
 
+/**
+ * devfreq_summary_show() - Show the summary of the devfreq devices
+ * @s:         seq_file instance to show the summary of devfreq devices
+ * @data:      not used
+ *
+ * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
+ * It helps that user can know the detailed information of the devfreq devices.
+ *
+ * Return 0 always because it shows the information without any data change.
+ */
+static int devfreq_summary_show(struct seq_file *s, void *data)
+{
+       struct devfreq *devfreq;
+       struct devfreq *p_devfreq = NULL;
+       unsigned long cur_freq, min_freq, max_freq;
+       unsigned int polling_ms;
+
+       seq_printf(s, "%-30s %-10s %-10s %-15s %10s %12s %12s %12s\n",
+                       "dev_name",
+                       "dev",
+                       "parent_dev",
+                       "governor",
+                       "polling_ms",
+                       "cur_freq_Hz",
+                       "min_freq_Hz",
+                       "max_freq_Hz");
+       seq_printf(s, "%30s %10s %10s %15s %10s %12s %12s %12s\n",
+                       "------------------------------",
+                       "----------",
+                       "----------",
+                       "---------------",
+                       "----------",
+                       "------------",
+                       "------------",
+                       "------------");
+
+       mutex_lock(&devfreq_list_lock);
+
+       list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
+#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
+               if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
+                                                       DEVFREQ_NAME_LEN)) {
+                       struct devfreq_passive_data *data = devfreq->data;
+
+                       if (data)
+                               p_devfreq = data->parent;
+               } else {
+                       p_devfreq = NULL;
+               }
+#endif
+
+               mutex_lock(&devfreq->lock);
+               cur_freq = devfreq->previous_freq,
+               get_freq_range(devfreq, &min_freq, &max_freq);
+               polling_ms = devfreq->profile->polling_ms,
+               mutex_unlock(&devfreq->lock);
+
+               seq_printf(s,
+                       "%-30s %-10s %-10s %-15s %10d %12ld %12ld %12ld\n",
+                       dev_name(devfreq->dev.parent),
+                       dev_name(&devfreq->dev),
+                       p_devfreq ? dev_name(&p_devfreq->dev) : "null",
+                       devfreq->governor_name,
+                       polling_ms,
+                       cur_freq,
+                       min_freq,
+                       max_freq);
+       }
+
+       mutex_unlock(&devfreq_list_lock);
+
+       return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
+
 static int __init devfreq_init(void)
 {
        devfreq_class = class_create(THIS_MODULE, "devfreq");
@@ -1659,6 +1736,11 @@ static int __init devfreq_init(void)
        }
        devfreq_class->dev_groups = devfreq_groups;
 
+       devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
+       debugfs_create_file("devfreq_summary", 0444,
+                               devfreq_debugfs, NULL,
+                               &devfreq_summary_fops);
+
        return 0;
 }
 subsys_initcall(devfreq_init);