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