drivers/w1/slaves/w1_ds2433.c

   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));