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80895392 EP |
1 | /* |
2 | * w1_ds2433.c - w1 family 23 (DS2433) driver | |
3 | * | |
4 | * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com> | |
5 | * | |
0a25e4d5 EP |
6 | * This source code is licensed under the GNU General Public License, |
7 | * Version 2. See the file COPYING for more details. | |
80895392 EP |
8 | */ |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/moduleparam.h> | |
13 | #include <linux/device.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/delay.h> | |
0a25e4d5 EP |
16 | #ifdef CONFIG_W1_F23_CRC |
17 | #include <linux/crc16.h> | |
f24ec7f6 EP |
18 | |
19 | #define CRC16_INIT 0 | |
20 | #define CRC16_VALID 0xb001 | |
21 | ||
0a25e4d5 | 22 | #endif |
80895392 EP |
23 | |
24 | #include "w1.h" | |
25 | #include "w1_io.h" | |
26 | #include "w1_int.h" | |
27 | #include "w1_family.h" | |
28 | ||
29 | MODULE_LICENSE("GPL"); | |
30 | MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>"); | |
31 | MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM"); | |
32 | ||
33 | #define W1_EEPROM_SIZE 512 | |
0a25e4d5 | 34 | #define W1_PAGE_COUNT 16 |
80895392 EP |
35 | #define W1_PAGE_SIZE 32 |
36 | #define W1_PAGE_BITS 5 | |
37 | #define W1_PAGE_MASK 0x1F | |
38 | ||
0a25e4d5 EP |
39 | #define W1_F23_TIME 300 |
40 | ||
80895392 EP |
41 | #define W1_F23_READ_EEPROM 0xF0 |
42 | #define W1_F23_WRITE_SCRATCH 0x0F | |
43 | #define W1_F23_READ_SCRATCH 0xAA | |
44 | #define W1_F23_COPY_SCRATCH 0x55 | |
45 | ||
0a25e4d5 EP |
46 | struct w1_f23_data { |
47 | u8 memory[W1_EEPROM_SIZE]; | |
48 | u32 validcrc; | |
49 | }; | |
50 | ||
80895392 EP |
51 | /** |
52 | * Check the file size bounds and adjusts count as needed. | |
0a25e4d5 | 53 | * This would not be needed if the file size didn't reset to 0 after a write. |
80895392 EP |
54 | */ |
55 | static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size) | |
56 | { | |
57 | if (off > size) | |
58 | return 0; | |
59 | ||
60 | if ((off + count) > size) | |
61 | return (size - off); | |
62 | ||
63 | return count; | |
64 | } | |
65 | ||
0a25e4d5 EP |
66 | #ifdef CONFIG_W1_F23_CRC |
67 | static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data, | |
68 | int block) | |
69 | { | |
70 | u8 wrbuf[3]; | |
71 | int off = block * W1_PAGE_SIZE; | |
72 | ||
73 | if (data->validcrc & (1 << block)) | |
74 | return 0; | |
75 | ||
76 | if (w1_reset_select_slave(sl)) { | |
77 | data->validcrc = 0; | |
78 | return -EIO; | |
79 | } | |
80 | ||
81 | wrbuf[0] = W1_F23_READ_EEPROM; | |
82 | wrbuf[1] = off & 0xff; | |
83 | wrbuf[2] = off >> 8; | |
84 | w1_write_block(sl->master, wrbuf, 3); | |
85 | w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE); | |
86 | ||
87 | /* cache the block if the CRC is valid */ | |
88 | if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID) | |
89 | data->validcrc |= (1 << block); | |
90 | ||
91 | return 0; | |
92 | } | |
93 | #endif /* CONFIG_W1_F23_CRC */ | |
94 | ||
95 | static ssize_t w1_f23_read_bin(struct kobject *kobj, char *buf, loff_t off, | |
96 | size_t count) | |
80895392 EP |
97 | { |
98 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
0a25e4d5 EP |
99 | #ifdef CONFIG_W1_F23_CRC |
100 | struct w1_f23_data *data = sl->family_data; | |
101 | int i, min_page, max_page; | |
102 | #else | |
80895392 | 103 | u8 wrbuf[3]; |
0a25e4d5 | 104 | #endif |
80895392 EP |
105 | |
106 | if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0) | |
107 | return 0; | |
108 | ||
109 | atomic_inc(&sl->refcnt); | |
110 | if (down_interruptible(&sl->master->mutex)) { | |
111 | count = 0; | |
112 | goto out_dec; | |
113 | } | |
114 | ||
0a25e4d5 EP |
115 | #ifdef CONFIG_W1_F23_CRC |
116 | ||
117 | min_page = (off >> W1_PAGE_BITS); | |
118 | max_page = (off + count - 1) >> W1_PAGE_BITS; | |
119 | for (i = min_page; i <= max_page; i++) { | |
120 | if (w1_f23_refresh_block(sl, data, i)) { | |
121 | count = -EIO; | |
122 | goto out_up; | |
123 | } | |
124 | } | |
125 | memcpy(buf, &data->memory[off], count); | |
126 | ||
127 | #else /* CONFIG_W1_F23_CRC */ | |
128 | ||
80895392 EP |
129 | /* read directly from the EEPROM */ |
130 | if (w1_reset_select_slave(sl)) { | |
131 | count = -EIO; | |
132 | goto out_up; | |
133 | } | |
134 | ||
135 | wrbuf[0] = W1_F23_READ_EEPROM; | |
136 | wrbuf[1] = off & 0xff; | |
137 | wrbuf[2] = off >> 8; | |
138 | w1_write_block(sl->master, wrbuf, 3); | |
139 | w1_read_block(sl->master, buf, count); | |
140 | ||
0a25e4d5 EP |
141 | #endif /* CONFIG_W1_F23_CRC */ |
142 | ||
80895392 EP |
143 | out_up: |
144 | up(&sl->master->mutex); | |
145 | out_dec: | |
146 | atomic_dec(&sl->refcnt); | |
147 | ||
148 | return count; | |
149 | } | |
150 | ||
151 | /** | |
152 | * Writes to the scratchpad and reads it back for verification. | |
0a25e4d5 EP |
153 | * Then copies the scratchpad to EEPROM. |
154 | * The data must be on one page. | |
80895392 EP |
155 | * The master must be locked. |
156 | * | |
157 | * @param sl The slave structure | |
158 | * @param addr Address for the write | |
159 | * @param len length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) | |
160 | * @param data The data to write | |
161 | * @return 0=Success -1=failure | |
162 | */ | |
163 | static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data) | |
164 | { | |
165 | u8 wrbuf[4]; | |
166 | u8 rdbuf[W1_PAGE_SIZE + 3]; | |
167 | u8 es = (addr + len - 1) & 0x1f; | |
168 | ||
169 | /* Write the data to the scratchpad */ | |
170 | if (w1_reset_select_slave(sl)) | |
171 | return -1; | |
172 | ||
173 | wrbuf[0] = W1_F23_WRITE_SCRATCH; | |
174 | wrbuf[1] = addr & 0xff; | |
175 | wrbuf[2] = addr >> 8; | |
176 | ||
177 | w1_write_block(sl->master, wrbuf, 3); | |
178 | w1_write_block(sl->master, data, len); | |
179 | ||
180 | /* Read the scratchpad and verify */ | |
181 | if (w1_reset_select_slave(sl)) | |
182 | return -1; | |
183 | ||
184 | w1_write_8(sl->master, W1_F23_READ_SCRATCH); | |
185 | w1_read_block(sl->master, rdbuf, len + 3); | |
186 | ||
187 | /* Compare what was read against the data written */ | |
188 | if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || | |
189 | (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) | |
190 | return -1; | |
191 | ||
192 | /* Copy the scratchpad to EEPROM */ | |
193 | if (w1_reset_select_slave(sl)) | |
194 | return -1; | |
195 | ||
196 | wrbuf[0] = W1_F23_COPY_SCRATCH; | |
197 | wrbuf[3] = es; | |
198 | w1_write_block(sl->master, wrbuf, 4); | |
199 | ||
200 | /* Sleep for 5 ms to wait for the write to complete */ | |
201 | msleep(5); | |
202 | ||
203 | /* Reset the bus to wake up the EEPROM (this may not be needed) */ | |
204 | w1_reset_bus(sl->master); | |
205 | ||
206 | return 0; | |
207 | } | |
208 | ||
209 | static ssize_t w1_f23_write_bin(struct kobject *kobj, char *buf, loff_t off, | |
210 | size_t count) | |
211 | { | |
212 | struct w1_slave *sl = kobj_to_w1_slave(kobj); | |
213 | int addr, len, idx; | |
214 | ||
215 | if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0) | |
216 | return 0; | |
217 | ||
0a25e4d5 EP |
218 | #ifdef CONFIG_W1_F23_CRC |
219 | /* can only write full blocks in cached mode */ | |
220 | if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { | |
f24ec7f6 | 221 | dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", |
0a25e4d5 EP |
222 | (int)off, count); |
223 | return -EINVAL; | |
224 | } | |
225 | ||
226 | /* make sure the block CRCs are valid */ | |
227 | for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { | |
228 | if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) { | |
229 | dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off); | |
230 | return -EINVAL; | |
231 | } | |
232 | } | |
233 | #endif /* CONFIG_W1_F23_CRC */ | |
234 | ||
80895392 EP |
235 | atomic_inc(&sl->refcnt); |
236 | if (down_interruptible(&sl->master->mutex)) { | |
237 | count = 0; | |
238 | goto out_dec; | |
239 | } | |
240 | ||
241 | /* Can only write data to one page at a time */ | |
242 | idx = 0; | |
243 | while (idx < count) { | |
244 | addr = off + idx; | |
245 | len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); | |
246 | if (len > (count - idx)) | |
247 | len = count - idx; | |
248 | ||
249 | if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) { | |
250 | count = -EIO; | |
251 | goto out_up; | |
252 | } | |
253 | idx += len; | |
254 | } | |
255 | ||
256 | out_up: | |
257 | up(&sl->master->mutex); | |
258 | out_dec: | |
259 | atomic_dec(&sl->refcnt); | |
260 | ||
261 | return count; | |
262 | } | |
263 | ||
264 | static struct bin_attribute w1_f23_bin_attr = { | |
265 | .attr = { | |
266 | .name = "eeprom", | |
267 | .mode = S_IRUGO | S_IWUSR, | |
268 | .owner = THIS_MODULE, | |
269 | }, | |
270 | .size = W1_EEPROM_SIZE, | |
271 | .read = w1_f23_read_bin, | |
272 | .write = w1_f23_write_bin, | |
273 | }; | |
274 | ||
275 | static int w1_f23_add_slave(struct w1_slave *sl) | |
276 | { | |
0a25e4d5 EP |
277 | int err; |
278 | #ifdef CONFIG_W1_F23_CRC | |
279 | struct w1_f23_data *data; | |
280 | ||
281 | data = kmalloc(sizeof(struct w1_f23_data), GFP_KERNEL); | |
282 | if (!data) | |
283 | return -ENOMEM; | |
284 | memset(data, 0, sizeof(struct w1_f23_data)); | |
285 | sl->family_data = data; | |
286 | ||
287 | #endif /* CONFIG_W1_F23_CRC */ | |
288 | ||
289 | err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr); | |
290 | ||
291 | #ifdef CONFIG_W1_F23_CRC | |
292 | if (err) | |
293 | kfree(data); | |
294 | #endif /* CONFIG_W1_F23_CRC */ | |
295 | ||
296 | return err; | |
80895392 EP |
297 | } |
298 | ||
299 | static void w1_f23_remove_slave(struct w1_slave *sl) | |
300 | { | |
0a25e4d5 | 301 | #ifdef CONFIG_W1_F23_CRC |
6044ec88 JJ |
302 | kfree(sl->family_data); |
303 | sl->family_data = NULL; | |
0a25e4d5 | 304 | #endif /* CONFIG_W1_F23_CRC */ |
80895392 EP |
305 | sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr); |
306 | } | |
307 | ||
308 | static struct w1_family_ops w1_f23_fops = { | |
309 | .add_slave = w1_f23_add_slave, | |
310 | .remove_slave = w1_f23_remove_slave, | |
311 | }; | |
312 | ||
313 | static struct w1_family w1_family_23 = { | |
314 | .fid = W1_EEPROM_DS2433, | |
315 | .fops = &w1_f23_fops, | |
316 | }; | |
317 | ||
318 | static int __init w1_f23_init(void) | |
319 | { | |
320 | return w1_register_family(&w1_family_23); | |
321 | } | |
322 | ||
323 | static void __exit w1_f23_fini(void) | |
324 | { | |
325 | w1_unregister_family(&w1_family_23); | |
326 | } | |
327 | ||
328 | module_init(w1_f23_init); | |
329 | module_exit(w1_f23_fini); |