drivers/base/power/opp/debugfs.c

   1 /*
   2  * Generic OPP debugfs interface
   3  *
   4  * Copyright (C) 2015-2016 Viresh Kumar <viresh.kumar@linaro.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/debugfs.h>
  14 #include <linux/device.h>
  15 #include <linux/err.h>
  16 #include <linux/init.h>
  17 #include <linux/limits.h>
  18
  19 #include "opp.h"
  20
  21 static struct dentry *rootdir;
  22
  23 static void opp_set_dev_name(const struct device *dev, char *name)
  24 {
  25         if (dev->parent)
  26                 snprintf(name, NAME_MAX, "%s-%s", dev_name(dev->parent),
  27                          dev_name(dev));
  28         else
  29                 snprintf(name, NAME_MAX, "%s", dev_name(dev));
  30 }
  31
  32 void opp_debug_remove_one(struct dev_pm_opp *opp)
  33 {
  34         debugfs_remove_recursive(opp->dentry);
  35 }
  36
  37 int opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table)
  38 {
  39         struct dentry *pdentry = opp_table->dentry;
  40         struct dentry *d;
  41         char name[25];  /* 20 chars for 64 bit value + 5 (opp:\0) */
  42
  43         /* Rate is unique to each OPP, use it to give opp-name */
  44         snprintf(name, sizeof(name), "opp:%lu", opp->rate);
  45
  46         /* Create per-opp directory */
  47         d = debugfs_create_dir(name, pdentry);
  48         if (!d)
  49                 return -ENOMEM;
  50
  51         if (!debugfs_create_bool("available", S_IRUGO, d, &opp->available))
  52                 return -ENOMEM;
  53
  54         if (!debugfs_create_bool("dynamic", S_IRUGO, d, &opp->dynamic))
  55                 return -ENOMEM;
  56
  57         if (!debugfs_create_bool("turbo", S_IRUGO, d, &opp->turbo))
  58                 return -ENOMEM;
  59
  60         if (!debugfs_create_bool("suspend", S_IRUGO, d, &opp->suspend))
  61                 return -ENOMEM;
  62
  63         if (!debugfs_create_ulong("rate_hz", S_IRUGO, d, &opp->rate))
  64                 return -ENOMEM;
  65
  66         if (!debugfs_create_ulong("u_volt_target", S_IRUGO, d, &opp->u_volt))
  67                 return -ENOMEM;
  68
  69         if (!debugfs_create_ulong("u_volt_min", S_IRUGO, d, &opp->u_volt_min))
  70                 return -ENOMEM;
  71
  72         if (!debugfs_create_ulong("u_volt_max", S_IRUGO, d, &opp->u_volt_max))
  73                 return -ENOMEM;
  74
  75         if (!debugfs_create_ulong("u_amp", S_IRUGO, d, &opp->u_amp))
  76                 return -ENOMEM;
  77
  78         if (!debugfs_create_ulong("clock_latency_ns", S_IRUGO, d,
  79                                   &opp->clock_latency_ns))
  80                 return -ENOMEM;
  81
  82         opp->dentry = d;
  83         return 0;
  84 }
  85
  86 static int opp_list_debug_create_dir(struct opp_device *opp_dev,
  87                                      struct opp_table *opp_table)
  88 {
  89         const struct device *dev = opp_dev->dev;
  90         struct dentry *d;
  91
  92         opp_set_dev_name(dev, opp_table->dentry_name);
  93
  94         /* Create device specific directory */
  95         d = debugfs_create_dir(opp_table->dentry_name, rootdir);
  96         if (!d) {
  97                 dev_err(dev, "%s: Failed to create debugfs dir\n", __func__);
  98                 return -ENOMEM;
  99         }
 100
 101         opp_dev->dentry = d;
 102         opp_table->dentry = d;
 103
 104         return 0;
 105 }
 106
 107 static int opp_list_debug_create_link(struct opp_device *opp_dev,
 108                                       struct opp_table *opp_table)
 109 {
 110         const struct device *dev = opp_dev->dev;
 111         char name[NAME_MAX];
 112         struct dentry *d;
 113
 114         opp_set_dev_name(opp_dev->dev, name);
 115
 116         /* Create device specific directory link */
 117         d = debugfs_create_symlink(name, rootdir, opp_table->dentry_name);
 118         if (!d) {
 119                 dev_err(dev, "%s: Failed to create link\n", __func__);
 120                 return -ENOMEM;
 121         }
 122
 123         opp_dev->dentry = d;
 124
 125         return 0;
 126 }
 127
 128 /**
 129  * opp_debug_register - add a device opp node to the debugfs 'opp' directory
 130  * @opp_dev: opp-dev pointer for device
 131  * @opp_table: the device-opp being added
 132  *
 133  * Dynamically adds device specific directory in debugfs 'opp' directory. If the
 134  * device-opp is shared with other devices, then links will be created for all
 135  * devices except the first.
 136  *
 137  * Return: 0 on success, otherwise negative error.
 138  */
 139 int opp_debug_register(struct opp_device *opp_dev, struct opp_table *opp_table)
 140 {
 141         if (!rootdir) {
 142                 pr_debug("%s: Uninitialized rootdir\n", __func__);
 143                 return -EINVAL;
 144         }
 145
 146         if (opp_table->dentry)
 147                 return opp_list_debug_create_link(opp_dev, opp_table);
 148
 149         return opp_list_debug_create_dir(opp_dev, opp_table);
 150 }
 151
 152 static void opp_migrate_dentry(struct opp_device *opp_dev,
 153                                struct opp_table *opp_table)
 154 {
 155         struct opp_device *new_dev;
 156         const struct device *dev;
 157         struct dentry *dentry;
 158
 159         /* Look for next opp-dev */
 160         list_for_each_entry(new_dev, &opp_table->dev_list, node)
 161                 if (new_dev != opp_dev)
 162                         break;
 163
 164         /* new_dev is guaranteed to be valid here */
 165         dev = new_dev->dev;
 166         debugfs_remove_recursive(new_dev->dentry);
 167
 168         opp_set_dev_name(dev, opp_table->dentry_name);
 169
 170         dentry = debugfs_rename(rootdir, opp_dev->dentry, rootdir,
 171                                 opp_table->dentry_name);
 172         if (!dentry) {
 173                 dev_err(dev, "%s: Failed to rename link from: %s to %s\n",
 174                         __func__, dev_name(opp_dev->dev), dev_name(dev));
 175                 return;
 176         }
 177
 178         new_dev->dentry = dentry;
 179         opp_table->dentry = dentry;
 180 }
 181
 182 /**
 183  * opp_debug_unregister - remove a device opp node from debugfs opp directory
 184  * @opp_dev: opp-dev pointer for device
 185  * @opp_table: the device-opp being removed
 186  *
 187  * Dynamically removes device specific directory from debugfs 'opp' directory.
 188  */
 189 void opp_debug_unregister(struct opp_device *opp_dev,
 190                           struct opp_table *opp_table)
 191 {
 192         if (opp_dev->dentry == opp_table->dentry) {
 193                 /* Move the real dentry object under another device */
 194                 if (!list_is_singular(&opp_table->dev_list)) {
 195                         opp_migrate_dentry(opp_dev, opp_table);
 196                         goto out;
 197                 }
 198                 opp_table->dentry = NULL;
 199         }
 200
 201         debugfs_remove_recursive(opp_dev->dentry);
 202
 203 out:
 204         opp_dev->dentry = NULL;
 205 }
 206
 207 static int __init opp_debug_init(void)
 208 {
 209         /* Create /sys/kernel/debug/opp directory */
 210         rootdir = debugfs_create_dir("opp", NULL);
 211         if (!rootdir) {
 212                 pr_err("%s: Failed to create root directory\n", __func__);
 213                 return -ENOMEM;
 214         }
 215
 216         return 0;
 217 }
 218 core_initcall(opp_debug_init);