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Subject[PATCH 5.5 278/399] PM / devfreq: Add debugfs support with devfreq_summary file
Date
From: Chanwoo Choi <cw00.choi@samsung.com>

[ Upstream commit 490a421bc575d1bf391a6ad5b582dcfbd0037724 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/devfreq/devfreq.c | 82 +++++++++++++++++++++++++++++++++++++++
1 file changed, 82 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 554d155106a5f..e99f082d15df5 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
@@ -1614,6 +1616,81 @@ 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");
@@ -1630,6 +1707,11 @@ 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);
--
2.20.1


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