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 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 + 1; i++) {
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
124out:
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 */
137static 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
170static 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
177static 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 + 1; i++) {
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
234out:
235	kfree(buf);
236	return ret;
237}
238
239static const struct file_operations regmap_access_fops = {
240	.open = simple_open,
241	.read = regmap_access_read_file,
242	.llseek = default_llseek,
243};
244
245void regmap_debugfs_init(struct regmap *map)
246{
247	map->debugfs = debugfs_create_dir(dev_name(map->dev),
248					  regmap_debugfs_root);
249	if (!map->debugfs) {
250		dev_warn(map->dev, "Failed to create debugfs directory\n");
251		return;
252	}
253
254	debugfs_create_file("name", 0400, map->debugfs,
255			    map, &regmap_name_fops);
256
257	if (map->max_register) {
258		debugfs_create_file("registers", 0400, map->debugfs,
259				    map, &regmap_map_fops);
260		debugfs_create_file("access", 0400, map->debugfs,
261				    map, &regmap_access_fops);
262	}
263
264	if (map->cache_type) {
265		debugfs_create_bool("cache_only", 0400, map->debugfs,
266				    &map->cache_only);
267		debugfs_create_bool("cache_dirty", 0400, map->debugfs,
268				    &map->cache_dirty);
269		debugfs_create_bool("cache_bypass", 0400, map->debugfs,
270				    &map->cache_bypass);
271	}
272}
273
274void regmap_debugfs_exit(struct regmap *map)
275{
276	debugfs_remove_recursive(map->debugfs);
277}
278
279void regmap_debugfs_initcall(void)
280{
281	regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
282	if (!regmap_debugfs_root) {
283		pr_warn("regmap: Failed to create debugfs root\n");
284		return;
285	}
286}
287