1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl> and
* Philip Edelbrock <phil@netroedge.com>
* Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (C) 2003 IBM Corp.
* Copyright (C) 2004 Jean Delvare <jdelvare@suse.de>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/capability.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
0x55, 0x56, 0x57, I2C_CLIENT_END };
/* Size of EEPROM in bytes */
#define EEPROM_SIZE 256
/* possible types of eeprom devices */
enum eeprom_nature {
UNKNOWN,
VAIO,
};
/* Each client has this additional data */
struct eeprom_data {
struct mutex update_lock;
u8 valid; /* bitfield, bit!=0 if slice is valid */
unsigned long last_updated[8]; /* In jiffies, 8 slices */
u8 data[EEPROM_SIZE]; /* Register values */
enum eeprom_nature nature;
};
static void eeprom_update_client(struct i2c_client *client, u8 slice)
{
struct eeprom_data *data = i2c_get_clientdata(client);
int i;
mutex_lock(&data->update_lock);
if (!(data->valid & (1 << slice)) ||
time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
for (i = slice << 5; i < (slice + 1) << 5; i += 32)
if (i2c_smbus_read_i2c_block_data(client, i,
32, data->data + i)
!= 32)
goto exit;
} else {
for (i = slice << 5; i < (slice + 1) << 5; i += 2) {
int word = i2c_smbus_read_word_data(client, i);
if (word < 0)
goto exit;
data->data[i] = word & 0xff;
data->data[i + 1] = word >> 8;
}
}
data->last_updated[slice] = jiffies;
data->valid |= (1 << slice);
}
exit:
mutex_unlock(&data->update_lock);
}
static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client = to_i2c_client(kobj_to_dev(kobj));
struct eeprom_data *data = i2c_get_clientdata(client);
u8 slice;
/* Only refresh slices which contain requested bytes */
for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
eeprom_update_client(client, slice);
/* Hide Vaio private settings to regular users:
- BIOS passwords: bytes 0x00 to 0x0f
- UUID: bytes 0x10 to 0x1f
- Serial number: 0xc0 to 0xdf */
if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) {
int i;
for (i = 0; i < count; i++) {
if ((off + i <= 0x1f) ||
(off + i >= 0xc0 && off + i <= 0xdf))
buf[i] = 0;
else
buf[i] = data->data[off + i];
}
} else {
memcpy(buf, &data->data[off], count);
}
return count;
}
static const struct bin_attribute eeprom_attr = {
.attr = {
.name = "eeprom",
.mode = S_IRUGO,
},
.size = EEPROM_SIZE,
.read = eeprom_read,
};
/* Return 0 if detection is successful, -ENODEV otherwise */
static int eeprom_detect(struct i2c_client *client, struct i2c_board_info *info)
{
struct i2c_adapter *adapter = client->adapter;
/* EDID EEPROMs are often 24C00 EEPROMs, which answer to all
addresses 0x50-0x57, but we only care about 0x50. So decline
attaching to addresses >= 0x51 on DDC buses */
if (!(adapter->class & I2C_CLASS_SPD) && client->addr >= 0x51)
return -ENODEV;
/* There are four ways we can read the EEPROM data:
(1) I2C block reads (faster, but unsupported by most adapters)
(2) Word reads (128% overhead)
(3) Consecutive byte reads (88% overhead, unsafe)
(4) Regular byte data reads (265% overhead)
The third and fourth methods are not implemented by this driver
because all known adapters support one of the first two. */
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)
&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
return -ENODEV;
strlcpy(info->type, "eeprom", I2C_NAME_SIZE);
return 0;
}
static int eeprom_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = client->adapter;
struct eeprom_data *data;
data = devm_kzalloc(&client->dev, sizeof(struct eeprom_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
memset(data->data, 0xff, EEPROM_SIZE);
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
data->nature = UNKNOWN;
/* Detect the Vaio nature of EEPROMs.
We use the "PCG-" or "VGN-" prefix as the signature. */
if (client->addr == 0x57
&& i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
char name[4];
name[0] = i2c_smbus_read_byte_data(client, 0x80);
name[1] = i2c_smbus_read_byte_data(client, 0x81);
name[2] = i2c_smbus_read_byte_data(client, 0x82);
name[3] = i2c_smbus_read_byte_data(client, 0x83);
if (!memcmp(name, "PCG-", 4) || !memcmp(name, "VGN-", 4)) {
dev_info(&client->dev, "Vaio EEPROM detected, "
"enabling privacy protection\n");
data->nature = VAIO;
}
}
/* create the sysfs eeprom file */
return sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
}
static int eeprom_remove(struct i2c_client *client)
{
sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
return 0;
}
static const struct i2c_device_id eeprom_id[] = {
{ "eeprom", 0 },
{ }
};
static struct i2c_driver eeprom_driver = {
.driver = {
.name = "eeprom",
},
.probe = eeprom_probe,
.remove = eeprom_remove,
.id_table = eeprom_id,
.class = I2C_CLASS_DDC | I2C_CLASS_SPD,
.detect = eeprom_detect,
.address_list = normal_i2c,
};
module_i2c_driver(eeprom_driver);
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
"Philip Edelbrock <phil@netroedge.com> and "
"Greg Kroah-Hartman <greg@kroah.com>");
MODULE_DESCRIPTION("I2C EEPROM driver");
MODULE_LICENSE("GPL");
|
