Root/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
21static struct dentry *regmap_debugfs_root;
22
23/* Calculate the length of a fixed format */
24static 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
30static 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
53static const struct file_operations regmap_name_fops = {
54    .open = simple_open,
55    .read = regmap_name_read_file,
56    .llseek = default_llseek,
57};
58
59static void regmap_debugfs_free_dump_cache(struct regmap *map)
60{
61    struct regmap_debugfs_off_cache *c;
62
63    while (!list_empty(&map->debugfs_off_cache)) {
64        c = list_first_entry(&map->debugfs_off_cache,
65                     struct regmap_debugfs_off_cache,
66                     list);
67        list_del(&c->list);
68        kfree(c);
69    }
70}
71
72/*
73 * Work out where the start offset maps into register numbers, bearing
74 * in mind that we suppress hidden registers.
75 */
76static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
77                          unsigned int base,
78                          loff_t from,
79                          loff_t *pos)
80{
81    struct regmap_debugfs_off_cache *c = NULL;
82    loff_t p = 0;
83    unsigned int i, ret;
84    unsigned int fpos_offset;
85    unsigned int reg_offset;
86
87    /*
88     * If we don't have a cache build one so we don't have to do a
89     * linear scan each time.
90     */
91    if (list_empty(&map->debugfs_off_cache)) {
92        for (i = base; i <= map->max_register; i += map->reg_stride) {
93            /* Skip unprinted registers, closing off cache entry */
94            if (!regmap_readable(map, i) ||
95                regmap_precious(map, i)) {
96                if (c) {
97                    c->max = p - 1;
98                    fpos_offset = c->max - c->min;
99                    reg_offset = fpos_offset / map->debugfs_tot_len;
100                    c->max_reg = c->base_reg + reg_offset;
101                    list_add_tail(&c->list,
102                              &map->debugfs_off_cache);
103                    c = NULL;
104                }
105
106                continue;
107            }
108
109            /* No cache entry? Start a new one */
110            if (!c) {
111                c = kzalloc(sizeof(*c), GFP_KERNEL);
112                if (!c) {
113                    regmap_debugfs_free_dump_cache(map);
114                    return base;
115                }
116                c->min = p;
117                c->base_reg = i;
118            }
119
120            p += map->debugfs_tot_len;
121        }
122    }
123
124    /* Close the last entry off if we didn't scan beyond it */
125    if (c) {
126        c->max = p - 1;
127        fpos_offset = c->max - c->min;
128        reg_offset = fpos_offset / map->debugfs_tot_len;
129        c->max_reg = c->base_reg + reg_offset;
130        list_add_tail(&c->list,
131                  &map->debugfs_off_cache);
132    }
133
134    /*
135     * This should never happen; we return above if we fail to
136     * allocate and we should never be in this code if there are
137     * no registers at all.
138     */
139    WARN_ON(list_empty(&map->debugfs_off_cache));
140    ret = base;
141
142    /* Find the relevant block:offset */
143    list_for_each_entry(c, &map->debugfs_off_cache, list) {
144        if (from >= c->min && from <= c->max) {
145            fpos_offset = from - c->min;
146            reg_offset = fpos_offset / map->debugfs_tot_len;
147            *pos = c->min + (reg_offset * map->debugfs_tot_len);
148            return c->base_reg + reg_offset;
149        }
150
151        *pos = c->max;
152        ret = c->max_reg;
153    }
154
155    return ret;
156}
157
158static inline void regmap_calc_tot_len(struct regmap *map,
159                       void *buf, size_t count)
160{
161    /* Calculate the length of a fixed format */
162    if (!map->debugfs_tot_len) {
163        map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
164                               buf, count);
165        map->debugfs_val_len = 2 * map->format.val_bytes;
166        map->debugfs_tot_len = map->debugfs_reg_len +
167            map->debugfs_val_len + 3; /* : \n */
168    }
169}
170
171static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
172                   unsigned int to, char __user *user_buf,
173                   size_t count, loff_t *ppos)
174{
175    size_t buf_pos = 0;
176    loff_t p = *ppos;
177    ssize_t ret;
178    int i;
179    char *buf;
180    unsigned int val, start_reg;
181
182    if (*ppos < 0 || !count)
183        return -EINVAL;
184
185    buf = kmalloc(count, GFP_KERNEL);
186    if (!buf)
187        return -ENOMEM;
188
189    regmap_calc_tot_len(map, buf, count);
190
191    /* Work out which register we're starting at */
192    start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
193
194    for (i = start_reg; i <= to; i += map->reg_stride) {
195        if (!regmap_readable(map, i))
196            continue;
197
198        if (regmap_precious(map, i))
199            continue;
200
201        /* If we're in the region the user is trying to read */
202        if (p >= *ppos) {
203            /* ...but not beyond it */
204            if (buf_pos + map->debugfs_tot_len > count)
205                break;
206
207            /* Format the register */
208            snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
209                 map->debugfs_reg_len, i - from);
210            buf_pos += map->debugfs_reg_len + 2;
211
212            /* Format the value, write all X if we can't read */
213            ret = regmap_read(map, i, &val);
214            if (ret == 0)
215                snprintf(buf + buf_pos, count - buf_pos,
216                     "%.*x", map->debugfs_val_len, val);
217            else
218                memset(buf + buf_pos, 'X',
219                       map->debugfs_val_len);
220            buf_pos += 2 * map->format.val_bytes;
221
222            buf[buf_pos++] = '\n';
223        }
224        p += map->debugfs_tot_len;
225    }
226
227    ret = buf_pos;
228
229    if (copy_to_user(user_buf, buf, buf_pos)) {
230        ret = -EFAULT;
231        goto out;
232    }
233
234    *ppos += buf_pos;
235
236out:
237    kfree(buf);
238    return ret;
239}
240
241static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
242                    size_t count, loff_t *ppos)
243{
244    struct regmap *map = file->private_data;
245
246    return regmap_read_debugfs(map, 0, map->max_register, user_buf,
247                   count, ppos);
248}
249
250#undef REGMAP_ALLOW_WRITE_DEBUGFS
251#ifdef REGMAP_ALLOW_WRITE_DEBUGFS
252/*
253 * This can be dangerous especially when we have clients such as
254 * PMICs, therefore don't provide any real compile time configuration option
255 * for this feature, people who want to use this will need to modify
256 * the source code directly.
257 */
258static ssize_t regmap_map_write_file(struct file *file,
259                     const char __user *user_buf,
260                     size_t count, loff_t *ppos)
261{
262    char buf[32];
263    size_t buf_size;
264    char *start = buf;
265    unsigned long reg, value;
266    struct regmap *map = file->private_data;
267
268    buf_size = min(count, (sizeof(buf)-1));
269    if (copy_from_user(buf, user_buf, buf_size))
270        return -EFAULT;
271    buf[buf_size] = 0;
272
273    while (*start == ' ')
274        start++;
275    reg = simple_strtoul(start, &start, 16);
276    while (*start == ' ')
277        start++;
278    if (strict_strtoul(start, 16, &value))
279        return -EINVAL;
280
281    /* Userspace has been fiddling around behind the kernel's back */
282    add_taint(TAINT_USER, LOCKDEP_NOW_UNRELIABLE);
283
284    regmap_write(map, reg, value);
285    return buf_size;
286}
287#else
288#define regmap_map_write_file NULL
289#endif
290
291static const struct file_operations regmap_map_fops = {
292    .open = simple_open,
293    .read = regmap_map_read_file,
294    .write = regmap_map_write_file,
295    .llseek = default_llseek,
296};
297
298static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
299                      size_t count, loff_t *ppos)
300{
301    struct regmap_range_node *range = file->private_data;
302    struct regmap *map = range->map;
303
304    return regmap_read_debugfs(map, range->range_min, range->range_max,
305                   user_buf, count, ppos);
306}
307
308static const struct file_operations regmap_range_fops = {
309    .open = simple_open,
310    .read = regmap_range_read_file,
311    .llseek = default_llseek,
312};
313
314static ssize_t regmap_access_read_file(struct file *file,
315                       char __user *user_buf, size_t count,
316                       loff_t *ppos)
317{
318    int reg_len, tot_len;
319    size_t buf_pos = 0;
320    loff_t p = 0;
321    ssize_t ret;
322    int i;
323    struct regmap *map = file->private_data;
324    char *buf;
325
326    if (*ppos < 0 || !count)
327        return -EINVAL;
328
329    buf = kmalloc(count, GFP_KERNEL);
330    if (!buf)
331        return -ENOMEM;
332
333    /* Calculate the length of a fixed format */
334    reg_len = regmap_calc_reg_len(map->max_register, buf, count);
335    tot_len = reg_len + 10; /* ': R W V P\n' */
336
337    for (i = 0; i <= map->max_register; i += map->reg_stride) {
338        /* Ignore registers which are neither readable nor writable */
339        if (!regmap_readable(map, i) && !regmap_writeable(map, i))
340            continue;
341
342        /* If we're in the region the user is trying to read */
343        if (p >= *ppos) {
344            /* ...but not beyond it */
345            if (buf_pos >= count - 1 - tot_len)
346                break;
347
348            /* Format the register */
349            snprintf(buf + buf_pos, count - buf_pos,
350                 "%.*x: %c %c %c %c\n",
351                 reg_len, i,
352                 regmap_readable(map, i) ? 'y' : 'n',
353                 regmap_writeable(map, i) ? 'y' : 'n',
354                 regmap_volatile(map, i) ? 'y' : 'n',
355                 regmap_precious(map, i) ? 'y' : 'n');
356
357            buf_pos += tot_len;
358        }
359        p += tot_len;
360    }
361
362    ret = buf_pos;
363
364    if (copy_to_user(user_buf, buf, buf_pos)) {
365        ret = -EFAULT;
366        goto out;
367    }
368
369    *ppos += buf_pos;
370
371out:
372    kfree(buf);
373    return ret;
374}
375
376static const struct file_operations regmap_access_fops = {
377    .open = simple_open,
378    .read = regmap_access_read_file,
379    .llseek = default_llseek,
380};
381
382void regmap_debugfs_init(struct regmap *map, const char *name)
383{
384    struct rb_node *next;
385    struct regmap_range_node *range_node;
386
387    INIT_LIST_HEAD(&map->debugfs_off_cache);
388
389    if (name) {
390        map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
391                          dev_name(map->dev), name);
392        name = map->debugfs_name;
393    } else {
394        name = dev_name(map->dev);
395    }
396
397    map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
398    if (!map->debugfs) {
399        dev_warn(map->dev, "Failed to create debugfs directory\n");
400        return;
401    }
402
403    debugfs_create_file("name", 0400, map->debugfs,
404                map, &regmap_name_fops);
405
406    if (map->max_register) {
407        debugfs_create_file("registers", 0400, map->debugfs,
408                    map, &regmap_map_fops);
409        debugfs_create_file("access", 0400, map->debugfs,
410                    map, &regmap_access_fops);
411    }
412
413    if (map->cache_type) {
414        debugfs_create_bool("cache_only", 0400, map->debugfs,
415                    &map->cache_only);
416        debugfs_create_bool("cache_dirty", 0400, map->debugfs,
417                    &map->cache_dirty);
418        debugfs_create_bool("cache_bypass", 0400, map->debugfs,
419                    &map->cache_bypass);
420    }
421
422    next = rb_first(&map->range_tree);
423    while (next) {
424        range_node = rb_entry(next, struct regmap_range_node, node);
425
426        if (range_node->name)
427            debugfs_create_file(range_node->name, 0400,
428                        map->debugfs, range_node,
429                        &regmap_range_fops);
430
431        next = rb_next(&range_node->node);
432    }
433}
434
435void regmap_debugfs_exit(struct regmap *map)
436{
437    debugfs_remove_recursive(map->debugfs);
438    regmap_debugfs_free_dump_cache(map);
439    kfree(map->debugfs_name);
440}
441
442void regmap_debugfs_initcall(void)
443{
444    regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
445    if (!regmap_debugfs_root) {
446        pr_warn("regmap: Failed to create debugfs root\n");
447        return;
448    }
449}
450

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