drivers/base/regmap/regmap-debugfs.c

   1 /*
   2  * Register map access API - debugfs
   3  *
   4  * Copyright 2011 Wolfson Microelectronics plc
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/slab.h>
  14 #include <linux/mutex.h>
  15 #include <linux/debugfs.h>
  16 #include <linux/uaccess.h>
  17 #include <linux/device.h>
  18
  19 #include "internal.h"
  20
  21 static struct dentry *regmap_debugfs_root;
  22
  23 /* Calculate the length of a fixed format  */
  24 static size_t regmap_calc_reg_len(int max_val, char *buf, size_t buf_size)
  25 {
  26         snprintf(buf, buf_size, "%x", max_val);
  27         return strlen(buf);
  28 }
  29
  30 static ssize_t regmap_name_read_file(struct file *file,
  31                                      char __user *user_buf, size_t count,
  32                                      loff_t *ppos)
  33 {
  34         struct regmap *map = file->private_data;
  35         int ret;
  36         char *buf;
  37
  38         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
  39         if (!buf)
  40                 return -ENOMEM;
  41
  42         ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
  43         if (ret < 0) {
  44                 kfree(buf);
  45                 return ret;
  46         }
  47
  48         ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
  49         kfree(buf);
  50         return ret;
  51 }
  52
  53 static const struct file_operations regmap_name_fops = {
  54         .open = simple_open,
  55         .read = regmap_name_read_file,
  56         .llseek = default_llseek,
  57 };
  58
  59 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
  60                                     size_t count, loff_t *ppos)
  61 {
  62         int reg_len, val_len, tot_len;
  63         size_t buf_pos = 0;
  64         loff_t p = 0;
  65         ssize_t ret;
  66         int i;
  67         struct regmap *map = file->private_data;
  68         char *buf;
  69         unsigned int val;
  70
  71         if (*ppos < 0 || !count)
  72                 return -EINVAL;
  73
  74         buf = kmalloc(count, GFP_KERNEL);
  75         if (!buf)
  76                 return -ENOMEM;
  77
  78         /* Calculate the length of a fixed format  */
  79         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
  80         val_len = 2 * map->format.val_bytes;
  81         tot_len = reg_len + val_len + 3;      /* : \n */
  82
  83         for (i = 0; i <= map->max_register; i += map->reg_stride) {
  84                 if (!regmap_readable(map, i))
  85                         continue;
  86
  87                 if (regmap_precious(map, i))
  88                         continue;
  89
  90                 /* If we're in the region the user is trying to read */
  91                 if (p >= *ppos) {
  92                         /* ...but not beyond it */
  93                         if (buf_pos >= count - 1 - tot_len)
  94                                 break;
  95
  96                         /* Format the register */
  97                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
  98                                  reg_len, i);
  99                         buf_pos += reg_len + 2;
 100
 101                         /* Format the value, write all X if we can't read */
 102                         ret = regmap_read(map, i, &val);
 103                         if (ret == 0)
 104                                 snprintf(buf + buf_pos, count - buf_pos,
 105                                          "%.*x", val_len, val);
 106                         else
 107                                 memset(buf + buf_pos, 'X', val_len);
 108                         buf_pos += 2 * map->format.val_bytes;
 109
 110                         buf[buf_pos++] = '\n';
 111                 }
 112                 p += tot_len;
 113         }
 114
 115         ret = buf_pos;
 116
 117         if (copy_to_user(user_buf, buf, buf_pos)) {
 118                 ret = -EFAULT;
 119                 goto out;
 120         }
 121
 122         *ppos += buf_pos;
 123
 124 out:
 125         kfree(buf);
 126         return ret;
 127 }
 128
 129 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 130 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 131 /*
 132  * This can be dangerous especially when we have clients such as
 133  * PMICs, therefore don't provide any real compile time configuration option
 134  * for this feature, people who want to use this will need to modify
 135  * the source code directly.
 136  */
 137 static ssize_t regmap_map_write_file(struct file *file,
 138                                      const char __user *user_buf,
 139                                      size_t count, loff_t *ppos)
 140 {
 141         char buf[32];
 142         size_t buf_size;
 143         char *start = buf;
 144         unsigned long reg, value;
 145         struct regmap *map = file->private_data;
 146
 147         buf_size = min(count, (sizeof(buf)-1));
 148         if (copy_from_user(buf, user_buf, buf_size))
 149                 return -EFAULT;
 150         buf[buf_size] = 0;
 151
 152         while (*start == ' ')
 153                 start++;
 154         reg = simple_strtoul(start, &start, 16);
 155         while (*start == ' ')
 156                 start++;
 157         if (strict_strtoul(start, 16, &value))
 158                 return -EINVAL;
 159
 160         /* Userspace has been fiddling around behind the kernel's back */
 161         add_taint(TAINT_USER);
 162
 163         regmap_write(map, reg, value);
 164         return buf_size;
 165 }
 166 #else
 167 #define regmap_map_write_file NULL
 168 #endif
 169
 170 static const struct file_operations regmap_map_fops = {
 171         .open = simple_open,
 172         .read = regmap_map_read_file,
 173         .write = regmap_map_write_file,
 174         .llseek = default_llseek,
 175 };
 176
 177 static ssize_t regmap_access_read_file(struct file *file,
 178                                        char __user *user_buf, size_t count,
 179                                        loff_t *ppos)
 180 {
 181         int reg_len, tot_len;
 182         size_t buf_pos = 0;
 183         loff_t p = 0;
 184         ssize_t ret;
 185         int i;
 186         struct regmap *map = file->private_data;
 187         char *buf;
 188
 189         if (*ppos < 0 || !count)
 190                 return -EINVAL;
 191
 192         buf = kmalloc(count, GFP_KERNEL);
 193         if (!buf)
 194                 return -ENOMEM;
 195
 196         /* Calculate the length of a fixed format  */
 197         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 198         tot_len = reg_len + 10; /* ': R W V P\n' */
 199
 200         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 201                 /* Ignore registers which are neither readable nor writable */
 202                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 203                         continue;
 204
 205                 /* If we're in the region the user is trying to read */
 206                 if (p >= *ppos) {
 207                         /* ...but not beyond it */
 208                         if (buf_pos >= count - 1 - tot_len)
 209                                 break;
 210
 211                         /* Format the register */
 212                         snprintf(buf + buf_pos, count - buf_pos,
 213                                  "%.*x: %c %c %c %c\n",
 214                                  reg_len, i,
 215                                  regmap_readable(map, i) ? 'y' : 'n',
 216                                  regmap_writeable(map, i) ? 'y' : 'n',
 217                                  regmap_volatile(map, i) ? 'y' : 'n',
 218                                  regmap_precious(map, i) ? 'y' : 'n');
 219
 220                         buf_pos += tot_len;
 221                 }
 222                 p += tot_len;
 223         }
 224
 225         ret = buf_pos;
 226
 227         if (copy_to_user(user_buf, buf, buf_pos)) {
 228                 ret = -EFAULT;
 229                 goto out;
 230         }
 231
 232         *ppos += buf_pos;
 233
 234 out:
 235         kfree(buf);
 236         return ret;
 237 }
 238
 239 static const struct file_operations regmap_access_fops = {
 240         .open = simple_open,
 241         .read = regmap_access_read_file,
 242         .llseek = default_llseek,
 243 };
 244
 245 void regmap_debugfs_init(struct regmap *map, const char *name)
 246 {
 247         if (name) {
 248                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 249                                               dev_name(map->dev), name);
 250                 name = map->debugfs_name;
 251         } else {
 252                 name = dev_name(map->dev);
 253         }
 254
 255         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 256         if (!map->debugfs) {
 257                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 258                 return;
 259         }
 260
 261         debugfs_create_file("name", 0400, map->debugfs,
 262                             map, &regmap_name_fops);
 263
 264         if (map->max_register) {
 265                 debugfs_create_file("registers", 0400, map->debugfs,
 266                                     map, &regmap_map_fops);
 267                 debugfs_create_file("access", 0400, map->debugfs,
 268                                     map, &regmap_access_fops);
 269         }
 270
 271         if (map->cache_type) {
 272                 debugfs_create_bool("cache_only", 0400, map->debugfs,
 273                                     &map->cache_only);
 274                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 275                                     &map->cache_dirty);
 276                 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
 277                                     &map->cache_bypass);
 278         }
 279 }
 280
 281 void regmap_debugfs_exit(struct regmap *map)
 282 {
 283         debugfs_remove_recursive(map->debugfs);
 284         kfree(map->debugfs_name);
 285 }
 286
 287 void regmap_debugfs_initcall(void)
 288 {
 289         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 290         if (!regmap_debugfs_root) {
 291                 pr_warn("regmap: Failed to create debugfs root\n");
 292                 return;
 293         }
 294 }