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/module.h>
  15 #include <linux/mutex.h>
  16 #include <linux/debugfs.h>
  17 #include <linux/uaccess.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_map_read_file(struct file *file, char __user *user_buf,
  37                                     size_t count, loff_t *ppos)
  38 {
  39         int reg_len, val_len, tot_len;
  40         size_t buf_pos = 0;
  41         loff_t p = 0;
  42         ssize_t ret;
  43         int i;
  44         struct regmap *map = file->private_data;
  45         char *buf;
  46         unsigned int val;
  47
  48         if (*ppos < 0 || !count)
  49                 return -EINVAL;
  50
  51         buf = kmalloc(count, GFP_KERNEL);
  52         if (!buf)
  53                 return -ENOMEM;
  54
  55         /* Calculate the length of a fixed format  */
  56         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
  57         val_len = 2 * map->format.val_bytes;
  58         tot_len = reg_len + val_len + 3;      /* : \n */
  59
  60         for (i = 0; i < map->max_register; i++) {
  61                 if (!regmap_readable(map, i))
  62                         continue;
  63
  64                 if (regmap_precious(map, i))
  65                         continue;
  66
  67                 /* If we're in the region the user is trying to read */
  68                 if (p >= *ppos) {
  69                         /* ...but not beyond it */
  70                         if (buf_pos >= count - 1 - tot_len)
  71                                 break;
  72
  73                         /* Format the register */
  74                         snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
  75                                  reg_len, i);
  76                         buf_pos += reg_len + 2;
  77
  78                         /* Format the value, write all X if we can't read */
  79                         ret = regmap_read(map, i, &val);
  80                         if (ret == 0)
  81                                 snprintf(buf + buf_pos, count - buf_pos,
  82                                          "%.*x", val_len, val);
  83                         else
  84                                 memset(buf + buf_pos, 'X', val_len);
  85                         buf_pos += 2 * map->format.val_bytes;
  86
  87                         buf[buf_pos++] = '\n';
  88                 }
  89                 p += tot_len;
  90         }
  91
  92         ret = buf_pos;
  93
  94         if (copy_to_user(user_buf, buf, buf_pos)) {
  95                 ret = -EFAULT;
  96                 goto out;
  97         }
  98
  99         *ppos += buf_pos;
 100
 101 out:
 102         kfree(buf);
 103         return ret;
 104 }
 105
 106 static const struct file_operations regmap_map_fops = {
 107         .open = regmap_open_file,
 108         .read = regmap_map_read_file,
 109         .llseek = default_llseek,
 110 };
 111
 112 static ssize_t regmap_access_read_file(struct file *file,
 113                                        char __user *user_buf, size_t count,
 114                                        loff_t *ppos)
 115 {
 116         int reg_len, tot_len;
 117         size_t buf_pos = 0;
 118         loff_t p = 0;
 119         ssize_t ret;
 120         int i;
 121         struct regmap *map = file->private_data;
 122         char *buf;
 123
 124         if (*ppos < 0 || !count)
 125                 return -EINVAL;
 126
 127         buf = kmalloc(count, GFP_KERNEL);
 128         if (!buf)
 129                 return -ENOMEM;
 130
 131         /* Calculate the length of a fixed format  */
 132         reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 133         tot_len = reg_len + 10; /* ': R W V P\n' */
 134
 135         for (i = 0; i < map->max_register; i++) {
 136                 /* Ignore registers which are neither readable nor writable */
 137                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 138                         continue;
 139
 140                 /* If we're in the region the user is trying to read */
 141                 if (p >= *ppos) {
 142                         /* ...but not beyond it */
 143                         if (buf_pos >= count - 1 - tot_len)
 144                                 break;
 145
 146                         /* Format the register */
 147                         snprintf(buf + buf_pos, count - buf_pos,
 148                                  "%.*x: %c %c %c %c\n",
 149                                  reg_len, i,
 150                                  regmap_readable(map, i) ? 'y' : 'n',
 151                                  regmap_writeable(map, i) ? 'y' : 'n',
 152                                  regmap_volatile(map, i) ? 'y' : 'n',
 153                                  regmap_precious(map, i) ? 'y' : 'n');
 154
 155                         buf_pos += tot_len;
 156                 }
 157                 p += tot_len;
 158         }
 159
 160         ret = buf_pos;
 161
 162         if (copy_to_user(user_buf, buf, buf_pos)) {
 163                 ret = -EFAULT;
 164                 goto out;
 165         }
 166
 167         *ppos += buf_pos;
 168
 169 out:
 170         kfree(buf);
 171         return ret;
 172 }
 173
 174 static const struct file_operations regmap_access_fops = {
 175         .open = regmap_open_file,
 176         .read = regmap_access_read_file,
 177         .llseek = default_llseek,
 178 };
 179
 180 void regmap_debugfs_init(struct regmap *map)
 181 {
 182         map->debugfs = debugfs_create_dir(dev_name(map->dev),
 183                                           regmap_debugfs_root);
 184         if (!map->debugfs) {
 185                 dev_warn(map->dev, "Failed to create debugfs directory\n");
 186                 return;
 187         }
 188
 189         if (map->max_register) {
 190                 debugfs_create_file("registers", 0400, map->debugfs,
 191                                     map, &regmap_map_fops);
 192                 debugfs_create_file("access", 0400, map->debugfs,
 193                                     map, &regmap_access_fops);
 194         }
 195 }
 196
 197 void regmap_debugfs_exit(struct regmap *map)
 198 {
 199         debugfs_remove_recursive(map->debugfs);
 200 }
 201
 202 void regmap_debugfs_initcall(void)
 203 {
 204         regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 205         if (!regmap_debugfs_root) {
 206                 pr_warn("regmap: Failed to create debugfs root\n");
 207                 return;
 208         }
 209 }