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_read_debugfs(struct regmap *map, unsigned int from,
  60                                    unsigned int to, char __user *user_buf,
  61                                    size_t count, loff_t *ppos)
  62 {
  63         size_t buf_pos = 0;
  64         loff_t p = 0;
  65         ssize_t ret;
  66         int i;
  67         char *buf;
  68         unsigned int val;
  69
  70         if (*ppos < 0 || !count)
  71                 return -EINVAL;
  72
  73         buf = kmalloc(count, GFP_KERNEL);
  74         if (!buf)
  75                 return -ENOMEM;
  76
  77         /* Calculate the length of a fixed format  */
  78         if (!map->debugfs_tot_len) {
  79                 map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
  80                                                            buf, count);
  81                 map->debugfs_val_len = 2 * map->format.val_bytes;
  82                 map->debugfs_tot_len = map->debugfs_reg_len +
  83                         map->debugfs_val_len + 3;      /* : \n */
  84         }
  85
  86         for (i = from; i <= to; i += map->reg_stride) {
  87                 if (!regmap_readable(map, i))
  88                         continue;
  89
  90                 if (regmap_precious(map, i))
  91                         continue;
  92
  93                 /* If we're in the region the user is trying to read */
  94                 if (p >= *ppos) {
  95                         /* ...but not beyond it */
  96                         if (buf_pos >= count - 1 - map->debugfs_tot_len)
  97                                 break;
  98
  99                         /* Format the register */
 100                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 101                                  map->debugfs_reg_len, i - from);
 102                         buf_pos += map->debugfs_reg_len + 2;
 103
 104                         /* Format the value, write all X if we can't read */
 105                         ret = regmap_read(map, i, &val);
 106                         if (ret == 0)
 107                                 snprintf(buf + buf_pos, count - buf_pos,
 108                                          "%.*x", map->debugfs_val_len, val);
 109                         else
 110                                 memset(buf + buf_pos, 'X',
 111                                        map->debugfs_val_len);
 112                         buf_pos += 2 * map->format.val_bytes;
 113
 114                         buf[buf_pos++] = '\n';
 115                 }
 116                 p += map->debugfs_tot_len;
 117         }
 118
 119         ret = buf_pos;
 120
 121         if (copy_to_user(user_buf, buf, buf_pos)) {
 122                 ret = -EFAULT;
 123                 goto out;
 124         }
 125
 126         *ppos += buf_pos;
 127
 128 out:
 129         kfree(buf);
 130         return ret;
 131 }
 132
 133 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 134                                     size_t count, loff_t *ppos)
 135 {
 136         struct regmap *map = file->private_data;
 137
 138         return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 139                                    count, ppos);
 140 }
 141
 142 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 143 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 144 /*
 145  * This can be dangerous especially when we have clients such as
 146  * PMICs, therefore don't provide any real compile time configuration option
 147  * for this feature, people who want to use this will need to modify
 148  * the source code directly.
 149  */
 150 static ssize_t regmap_map_write_file(struct file *file,
 151                                      const char __user *user_buf,
 152                                      size_t count, loff_t *ppos)
 153 {
 154         char buf[32];
 155         size_t buf_size;
 156         char *start = buf;
 157         unsigned long reg, value;
 158         struct regmap *map = file->private_data;
 159
 160         buf_size = min(count, (sizeof(buf)-1));
 161         if (copy_from_user(buf, user_buf, buf_size))
 162                 return -EFAULT;
 163         buf[buf_size] = 0;
 164
 165         while (*start == ' ')
 166                 start++;
 167         reg = simple_strtoul(start, &start, 16);
 168         while (*start == ' ')
 169                 start++;
 170         if (strict_strtoul(start, 16, &value))
 171                 return -EINVAL;
 172
 173         /* Userspace has been fiddling around behind the kernel's back */
 174         add_taint(TAINT_USER);
 175
 176         regmap_write(map, reg, value);
 177         return buf_size;
 178 }
 179 #else
 180 #define regmap_map_write_file NULL
 181 #endif
 182
 183 static const struct file_operations regmap_map_fops = {
 184         .open = simple_open,
 185         .read = regmap_map_read_file,
 186         .write = regmap_map_write_file,
 187         .llseek = default_llseek,
 188 };
 189
 190 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 191                                       size_t count, loff_t *ppos)
 192 {
 193         struct regmap_range_node *range = file->private_data;
 194         struct regmap *map = range->map;
 195
 196         return regmap_read_debugfs(map, range->range_min, range->range_max,
 197                                    user_buf, count, ppos);
 198 }
 199
 200 static const struct file_operations regmap_range_fops = {
 201         .open = simple_open,
 202         .read = regmap_range_read_file,
 203         .llseek = default_llseek,
 204 };
 205
 206 static ssize_t regmap_access_read_file(struct file *file,
 207                                        char __user *user_buf, size_t count,
 208                                        loff_t *ppos)
 209 {
 210         int reg_len, tot_len;
 211         size_t buf_pos = 0;
 212         loff_t p = 0;
 213         ssize_t ret;
 214         int i;
 215         struct regmap *map = file->private_data;
 216         char *buf;
 217
 218         if (*ppos < 0 || !count)
 219                 return -EINVAL;
 220
 221         buf = kmalloc(count, GFP_KERNEL);
 222         if (!buf)
 223                 return -ENOMEM;
 224
 225         /* Calculate the length of a fixed format  */
 226         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 227         tot_len = reg_len + 10; /* ': R W V P\n' */
 228
 229         for (i = 0; i <= map->max_register; i += map->reg_stride) {
 230                 /* Ignore registers which are neither readable nor writable */
 231                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 232                         continue;
 233
 234                 /* If we're in the region the user is trying to read */
 235                 if (p >= *ppos) {
 236                         /* ...but not beyond it */
 237                         if (buf_pos >= count - 1 - tot_len)
 238                                 break;
 239
 240                         /* Format the register */
 241                         snprintf(buf + buf_pos, count - buf_pos,
 242                                  "%.*x: %c %c %c %c\n",
 243                                  reg_len, i,
 244                                  regmap_readable(map, i) ? 'y' : 'n',
 245                                  regmap_writeable(map, i) ? 'y' : 'n',
 246                                  regmap_volatile(map, i) ? 'y' : 'n',
 247                                  regmap_precious(map, i) ? 'y' : 'n');
 248
 249                         buf_pos += tot_len;
 250                 }
 251                 p += tot_len;
 252         }
 253
 254         ret = buf_pos;
 255
 256         if (copy_to_user(user_buf, buf, buf_pos)) {
 257                 ret = -EFAULT;
 258                 goto out;
 259         }
 260
 261         *ppos += buf_pos;
 262
 263 out:
 264         kfree(buf);
 265         return ret;
 266 }
 267
 268 static const struct file_operations regmap_access_fops = {
 269         .open = simple_open,
 270         .read = regmap_access_read_file,
 271         .llseek = default_llseek,
 272 };
 273
 274 void regmap_debugfs_init(struct regmap *map, const char *name)
 275 {
 276         struct rb_node *next;
 277         struct regmap_range_node *range_node;
 278
 279         if (name) {
 280                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 281                                               dev_name(map->dev), name);
 282                 name = map->debugfs_name;
 283         } else {
 284                 name = dev_name(map->dev);
 285         }
 286
 287         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 288         if (!map->debugfs) {
 289                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 290                 return;
 291         }
 292
 293         debugfs_create_file("name", 0400, map->debugfs,
 294                             map, &regmap_name_fops);
 295
 296         if (map->max_register) {
 297                 debugfs_create_file("registers", 0400, map->debugfs,
 298                                     map, &regmap_map_fops);
 299                 debugfs_create_file("access", 0400, map->debugfs,
 300                                     map, &regmap_access_fops);
 301         }
 302
 303         if (map->cache_type) {
 304                 debugfs_create_bool("cache_only", 0400, map->debugfs,
 305                                     &map->cache_only);
 306                 debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 307                                     &map->cache_dirty);
 308                 debugfs_create_bool("cache_bypass", 0400, map->debugfs,
 309                                     &map->cache_bypass);
 310         }
 311
 312         next = rb_first(&map->range_tree);
 313         while (next) {
 314                 range_node = rb_entry(next, struct regmap_range_node, node);
 315
 316                 if (range_node->name)
 317                         debugfs_create_file(range_node->name, 0400,
 318                                             map->debugfs, range_node,
 319                                             &regmap_range_fops);
 320
 321                 next = rb_next(&range_node->node);
 322         }
 323 }
 324
 325 void regmap_debugfs_exit(struct regmap *map)
 326 {
 327         debugfs_remove_recursive(map->debugfs);
 328         kfree(map->debugfs_name);
 329 }
 330
 331 void regmap_debugfs_initcall(void)
 332 {
 333         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 334         if (!regmap_debugfs_root) {
 335                 pr_warn("regmap: Failed to create debugfs root\n");
 336                 return;
 337         }
 338 }