1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * w1_ds2433.c - w1 family 23 (DS2433) & 43 (DS28EC20) eeprom driver 4 * 5 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com> 6 * Copyright (c) 2023 Marc Ferland <marc.ferland@sonatest.com> 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/moduleparam.h> 12 #include <linux/device.h> 13 #include <linux/types.h> 14 #include <linux/delay.h> 15 #include <linux/slab.h> 16 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 17 #include <linux/crc16.h> 18 19 #define CRC16_INIT 0 20 #define CRC16_VALID 0xb001 21 22 #endif 23 24 #include <linux/w1.h> 25 26 #define W1_EEPROM_DS2433 0x23 27 #define W1_EEPROM_DS28EC20 0x43 28 29 #define W1_EEPROM_DS2433_SIZE 512 30 #define W1_EEPROM_DS28EC20_SIZE 2560 31 32 #define W1_PAGE_SIZE 32 33 #define W1_PAGE_BITS 5 34 #define W1_PAGE_MASK 0x1F 35 #define W1_VALIDCRC_MAX 96 36 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 42 struct ds2433_config { 43 size_t eeprom_size; /* eeprom size in bytes */ 44 unsigned int page_count; /* number of 256 bits pages */ 45 unsigned int tprog; /* time in ms for page programming */ 46 }; 47 48 static const struct ds2433_config config_f23 = { 49 .eeprom_size = W1_EEPROM_DS2433_SIZE, 50 .page_count = 16, 51 .tprog = 5, 52 }; 53 54 static const struct ds2433_config config_f43 = { 55 .eeprom_size = W1_EEPROM_DS28EC20_SIZE, 56 .page_count = 80, 57 .tprog = 10, 58 }; 59 60 struct w1_f23_data { 61 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 62 u8 *memory; 63 DECLARE_BITMAP(validcrc, W1_VALIDCRC_MAX); 64 #endif 65 const struct ds2433_config *cfg; 66 }; 67 68 /* 69 * Check the file size bounds and adjusts count as needed. 70 * This would not be needed if the file size didn't reset to 0 after a write. 71 */ 72 static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size) 73 { 74 if (off > size) 75 return 0; 76 77 if ((off + count) > size) 78 return (size - off); 79 80 return count; 81 } 82 83 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 84 static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data, 85 int block) 86 { 87 u8 wrbuf[3]; 88 int off = block * W1_PAGE_SIZE; 89 90 if (test_bit(block, data->validcrc)) 91 return 0; 92 93 if (w1_reset_select_slave(sl)) { 94 bitmap_zero(data->validcrc, data->cfg->page_count); 95 return -EIO; 96 } 97 98 wrbuf[0] = W1_F23_READ_EEPROM; 99 wrbuf[1] = off & 0xff; 100 wrbuf[2] = off >> 8; 101 w1_write_block(sl->master, wrbuf, 3); 102 w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE); 103 104 /* cache the block if the CRC is valid */ 105 if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID) 106 set_bit(block, data->validcrc); 107 108 return 0; 109 } 110 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 111 112 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj, 113 struct bin_attribute *bin_attr, char *buf, 114 loff_t off, size_t count) 115 { 116 struct w1_slave *sl = kobj_to_w1_slave(kobj); 117 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 118 struct w1_f23_data *data = sl->family_data; 119 int i, min_page, max_page; 120 #else 121 u8 wrbuf[3]; 122 #endif 123 124 count = w1_f23_fix_count(off, count, bin_attr->size); 125 if (!count) 126 return 0; 127 128 mutex_lock(&sl->master->bus_mutex); 129 130 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 131 132 min_page = (off >> W1_PAGE_BITS); 133 max_page = (off + count - 1) >> W1_PAGE_BITS; 134 for (i = min_page; i <= max_page; i++) { 135 if (w1_f23_refresh_block(sl, data, i)) { 136 count = -EIO; 137 goto out_up; 138 } 139 } 140 memcpy(buf, &data->memory[off], count); 141 142 #else /* CONFIG_W1_SLAVE_DS2433_CRC */ 143 144 /* read directly from the EEPROM */ 145 if (w1_reset_select_slave(sl)) { 146 count = -EIO; 147 goto out_up; 148 } 149 150 wrbuf[0] = W1_F23_READ_EEPROM; 151 wrbuf[1] = off & 0xff; 152 wrbuf[2] = off >> 8; 153 w1_write_block(sl->master, wrbuf, 3); 154 w1_read_block(sl->master, buf, count); 155 156 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 157 158 out_up: 159 mutex_unlock(&sl->master->bus_mutex); 160 161 return count; 162 } 163 164 /** 165 * w1_f23_write() - Writes to the scratchpad and reads it back for verification. 166 * @sl: The slave structure 167 * @addr: Address for the write 168 * @len: length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK)) 169 * @data: The data to write 170 * 171 * Then copies the scratchpad to EEPROM. 172 * The data must be on one page. 173 * The master must be locked. 174 * 175 * Return: 0=Success, -1=failure 176 */ 177 static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data) 178 { 179 struct w1_f23_data *f23 = sl->family_data; 180 u8 wrbuf[4]; 181 u8 rdbuf[W1_PAGE_SIZE + 3]; 182 u8 es = (addr + len - 1) & 0x1f; 183 184 /* Write the data to the scratchpad */ 185 if (w1_reset_select_slave(sl)) 186 return -1; 187 188 wrbuf[0] = W1_F23_WRITE_SCRATCH; 189 wrbuf[1] = addr & 0xff; 190 wrbuf[2] = addr >> 8; 191 192 w1_write_block(sl->master, wrbuf, 3); 193 w1_write_block(sl->master, data, len); 194 195 /* Read the scratchpad and verify */ 196 if (w1_reset_select_slave(sl)) 197 return -1; 198 199 w1_write_8(sl->master, W1_F23_READ_SCRATCH); 200 w1_read_block(sl->master, rdbuf, len + 3); 201 202 /* Compare what was read against the data written */ 203 if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) || 204 (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0)) 205 return -1; 206 207 /* Copy the scratchpad to EEPROM */ 208 if (w1_reset_select_slave(sl)) 209 return -1; 210 211 wrbuf[0] = W1_F23_COPY_SCRATCH; 212 wrbuf[3] = es; 213 w1_write_block(sl->master, wrbuf, 4); 214 215 /* Sleep for tprog ms to wait for the write to complete */ 216 msleep(f23->cfg->tprog); 217 218 /* Reset the bus to wake up the EEPROM (this may not be needed) */ 219 w1_reset_bus(sl->master); 220 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 221 clear_bit(addr >> W1_PAGE_BITS, f23->validcrc); 222 #endif 223 return 0; 224 } 225 226 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj, 227 struct bin_attribute *bin_attr, char *buf, 228 loff_t off, size_t count) 229 { 230 struct w1_slave *sl = kobj_to_w1_slave(kobj); 231 int addr, len, idx; 232 233 count = w1_f23_fix_count(off, count, bin_attr->size); 234 if (!count) 235 return 0; 236 237 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 238 /* can only write full blocks in cached mode */ 239 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) { 240 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n", 241 (int)off, count); 242 return -EINVAL; 243 } 244 245 /* make sure the block CRCs are valid */ 246 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) { 247 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) { 248 dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off); 249 return -EINVAL; 250 } 251 } 252 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 253 254 mutex_lock(&sl->master->bus_mutex); 255 256 /* Can only write data to one page at a time */ 257 idx = 0; 258 while (idx < count) { 259 addr = off + idx; 260 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK); 261 if (len > (count - idx)) 262 len = count - idx; 263 264 if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) { 265 count = -EIO; 266 goto out_up; 267 } 268 idx += len; 269 } 270 271 out_up: 272 mutex_unlock(&sl->master->bus_mutex); 273 274 return count; 275 } 276 277 static struct bin_attribute bin_attr_f23_eeprom = { 278 .attr = { .name = "eeprom", .mode = 0644 }, 279 .read = eeprom_read, 280 .write = eeprom_write, 281 .size = W1_EEPROM_DS2433_SIZE, 282 }; 283 284 static struct bin_attribute bin_attr_f43_eeprom = { 285 .attr = { .name = "eeprom", .mode = 0644 }, 286 .read = eeprom_read, 287 .write = eeprom_write, 288 .size = W1_EEPROM_DS28EC20_SIZE, 289 }; 290 291 static struct bin_attribute *w1_f23_bin_attributes[] = { 292 &bin_attr_f23_eeprom, 293 NULL, 294 }; 295 296 static const struct attribute_group w1_f23_group = { 297 .bin_attrs = w1_f23_bin_attributes, 298 }; 299 300 static const struct attribute_group *w1_f23_groups[] = { 301 &w1_f23_group, 302 NULL, 303 }; 304 305 static struct bin_attribute *w1_f43_bin_attributes[] = { 306 &bin_attr_f43_eeprom, 307 NULL, 308 }; 309 310 static const struct attribute_group w1_f43_group = { 311 .bin_attrs = w1_f43_bin_attributes, 312 }; 313 314 static const struct attribute_group *w1_f43_groups[] = { 315 &w1_f43_group, 316 NULL, 317 }; 318 319 static int w1_f23_add_slave(struct w1_slave *sl) 320 { 321 struct w1_f23_data *data; 322 323 data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL); 324 if (!data) 325 return -ENOMEM; 326 327 switch (sl->family->fid) { 328 case W1_EEPROM_DS2433: 329 data->cfg = &config_f23; 330 break; 331 case W1_EEPROM_DS28EC20: 332 data->cfg = &config_f43; 333 break; 334 } 335 336 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 337 if (data->cfg->page_count > W1_VALIDCRC_MAX) { 338 dev_err(&sl->dev, "page count too big for crc bitmap\n"); 339 kfree(data); 340 return -EINVAL; 341 } 342 data->memory = kzalloc(data->cfg->eeprom_size, GFP_KERNEL); 343 if (!data->memory) { 344 kfree(data); 345 return -ENOMEM; 346 } 347 bitmap_zero(data->validcrc, data->cfg->page_count); 348 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 349 sl->family_data = data; 350 351 return 0; 352 } 353 354 static void w1_f23_remove_slave(struct w1_slave *sl) 355 { 356 struct w1_f23_data *data = sl->family_data; 357 sl->family_data = NULL; 358 #ifdef CONFIG_W1_SLAVE_DS2433_CRC 359 kfree(data->memory); 360 #endif /* CONFIG_W1_SLAVE_DS2433_CRC */ 361 kfree(data); 362 } 363 364 static const struct w1_family_ops w1_f23_fops = { 365 .add_slave = w1_f23_add_slave, 366 .remove_slave = w1_f23_remove_slave, 367 .groups = w1_f23_groups, 368 }; 369 370 static const struct w1_family_ops w1_f43_fops = { 371 .add_slave = w1_f23_add_slave, 372 .remove_slave = w1_f23_remove_slave, 373 .groups = w1_f43_groups, 374 }; 375 376 static struct w1_family w1_family_23 = { 377 .fid = W1_EEPROM_DS2433, 378 .fops = &w1_f23_fops, 379 }; 380 381 static struct w1_family w1_family_43 = { 382 .fid = W1_EEPROM_DS28EC20, 383 .fops = &w1_f43_fops, 384 }; 385 386 static int __init w1_ds2433_init(void) 387 { 388 int err; 389 390 err = w1_register_family(&w1_family_23); 391 if (err) 392 return err; 393 394 err = w1_register_family(&w1_family_43); 395 if (err) 396 goto err_43; 397 398 return 0; 399 400 err_43: 401 w1_unregister_family(&w1_family_23); 402 return err; 403 } 404 405 static void __exit w1_ds2433_exit(void) 406 { 407 w1_unregister_family(&w1_family_23); 408 w1_unregister_family(&w1_family_43); 409 } 410 411 module_init(w1_ds2433_init); 412 module_exit(w1_ds2433_exit); 413 414 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>"); 415 MODULE_AUTHOR("Marc Ferland <marc.ferland@sonatest.com>"); 416 MODULE_DESCRIPTION("w1 family 23/43 driver for DS2433 (4kb) and DS28EC20 (20kb)"); 417 MODULE_LICENSE("GPL"); 418 MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433)); 419 MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS28EC20)); 420