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