[PATCH] PM / devfreq: Add debugfs support with devfreq_summary file

From: Chanwoo Choi
Date: Thu Dec 26 2019 - 01:01:24 EST


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

[For example on Exynos5422-based Odroid-XU3 board]
- In order to show the multiple governors on devfreq_summay result,
change the governor of devfreq0 from simple_ondemand to userspace.

$ cat /sys/kernel/debug/devfreq/devfreq_summary
dev name dev parent dev governor cur_freq min_freq max_freq
------------------------------ ---------- ---------- --------------- ------------ ------------ ------------
10c20000.memory-controller devfreq0 userspace 165000000 165000000 825000000
soc:bus_wcore devfreq1 simple_ondemand 400000000 84000000 400000000
soc:bus_noc devfreq2 devfreq1 passive 100000000 67000000 100000000
soc:bus_fsys_apb devfreq3 devfreq1 passive 200000000 100000000 200000000
soc:bus_fsys devfreq4 devfreq1 passive 200000000 100000000 200000000
soc:bus_fsys2 devfreq5 devfreq1 passive 150000000 75000000 150000000
soc:bus_mfc devfreq6 devfreq1 passive 333000000 96000000 333000000
soc:bus_gen devfreq7 devfreq1 passive 267000000 89000000 267000000
soc:bus_peri devfreq8 devfreq1 passive 67000000 67000000 67000000
soc:bus_g2d devfreq9 devfreq1 passive 333000000 84000000 333000000
soc:bus_g2d_acp devfreq10 devfreq1 passive 267000000 67000000 267000000
soc:bus_jpeg devfreq11 devfreq1 passive 300000000 75000000 300000000
soc:bus_jpeg_apb devfreq12 devfreq1 passive 167000000 84000000 167000000
soc:bus_disp1_fimd devfreq13 devfreq1 passive 200000000 120000000 200000000
soc:bus_disp1 devfreq14 devfreq1 passive 300000000 120000000 300000000
soc:bus_gscl_scaler devfreq15 devfreq1 passive 300000000 150000000 300000000
soc:bus_mscl devfreq16 devfreq1 passive 400000000 84000000 400000000

Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
---
drivers/devfreq/devfreq.c | 65 +++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index acd21345a070..d7177cc0a914 100644
--- 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
@@ -1670,6 +1672,62 @@ static struct attribute *devfreq_attrs[] = {
};
ATTRIBUTE_GROUPS(devfreq);

+static int devfreq_summary_show(struct seq_file *s, void *data)
+{
+ struct devfreq *devfreq;
+ struct devfreq *parent_devfreq;
+ unsigned long cur_freq, min_freq, max_freq;
+
+ seq_printf(s, "%-30s %-10s %-10s %-15s %-12s %-12s %-12s\n",
+ "dev name",
+ "dev",
+ "parent dev",
+ "governor",
+ "cur_freq",
+ "min_freq",
+ "max_freq");
+ seq_printf(s, "%-30s %-10s %-10s %-15s %-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;
+ parent_devfreq = data->parent;
+ } else {
+ parent_devfreq = NULL;
+ }
+#endif
+ mutex_lock(&devfreq->lock);
+ cur_freq = devfreq->previous_freq,
+ get_freq_range(devfreq, &min_freq, &max_freq);
+ mutex_unlock(&devfreq->lock);
+
+ seq_printf(s, "%-30s %-10s %-10s %-15s %-12ld %-12ld %-12ld\n",
+ dev_name(devfreq->dev.parent),
+ dev_name(&devfreq->dev),
+ parent_devfreq ? dev_name(&parent_devfreq->dev) : "",
+ devfreq->governor_name,
+ 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");
@@ -1686,6 +1744,13 @@ static int __init devfreq_init(void)
}
devfreq_class->dev_groups = devfreq_groups;

+ devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
+ if (PTR_ERR(devfreq_debugfs) != -ENODEV && IS_ERR(devfreq_debugfs))
+ pr_warn("%s: couldn't create debugfs dir\n", __FILE__);
+
+ debugfs_create_file("devfreq_summary", 0444, devfreq_debugfs, NULL,
+ &devfreq_summary_fops);
+
return 0;
}
subsys_initcall(devfreq_init);
--
2.17.1