1 /* 2 * Copyright (C) 2017 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 20 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN 21 * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 23 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 24 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 25 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 26 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 27 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 */ 31 32 #define BTSTACK_FILE__ "btstack_tlv_flash_bank.c" 33 34 #include "btstack_tlv.h" 35 #include "btstack_tlv_flash_bank.h" 36 #include "btstack_debug.h" 37 #include "btstack_util.h" 38 #include "btstack_debug.h" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 // Header: 44 // - Magic: 'BTstack' 45 // - Status: 46 // - bits 765432: reserved 47 // - bits 10: epoch 48 49 // Entries 50 // - Tag: 32 bit 51 // - Len: 32 bit 52 // - Delete: 32 delete field - only used with ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 53 // - Value: Len in bytes 54 55 // ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 56 // 57 // Most Flash implementations allow to: 58 // - erase sector -> all values are 0xff 59 // - write value (1s -> 0s) 60 // - overwrite value with zero (remaining 1s -> 0s) 61 // 62 // We use the ability to overwrite a value with zeros to mark deleted enttries (by writing zero into the tag field). 63 // Some targets, E.g. Kinetix K64F, do enot allow for that. 64 // 65 // With ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD an extra field is reserved to indicate a deleted tag, while keeping main logic 66 // 67 // With ENABLE_TLV_FLASH_WRITE_ONCE, tags are never marked as deleted. Instead, an emtpy tag will be written instead. 68 // Also, lookup and migrate requires to always search until the end of the valid bank 69 70 #if defined (ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD) && defined (ENABLE_TLV_FLASH_WRITE_ONCE) 71 #error "Please define either ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD or ENABLE_TLV_FLASH_WRITE_ONCE" 72 #endif 73 74 #define BTSTACK_TLV_HEADER_LEN 8 75 76 #ifndef BTSTACK_FLASH_ALIGNMENT_MAX 77 #define BTSTACK_FLASH_ALIGNMENT_MAX 8 78 #endif 79 80 static const char * btstack_tlv_header_magic = "BTstack"; 81 82 // TLV Iterator 83 typedef struct { 84 int bank; 85 uint32_t offset; 86 uint32_t size; 87 uint32_t tag; 88 uint32_t len; 89 } tlv_iterator_t; 90 91 static uint32_t btstack_tlv_flash_bank_align_size(btstack_tlv_flash_bank_t * self, uint32_t size){ 92 uint32_t alignment = self->hal_flash_bank_impl->get_alignment(self->hal_flash_bank_context); 93 return (size + alignment - 1) & ~(alignment - 1); 94 } 95 96 // support unaligned flash read/writes 97 // strategy: increase size to meet alignment, perform unaligned read/write of last chunk with helper buffer 98 99 static void btstack_tlv_flash_bank_read(btstack_tlv_flash_bank_t * self, int bank, uint32_t offset, uint8_t * buffer, uint32_t size){ 100 101 // read main data 102 uint32_t aligment = self->hal_flash_bank_impl->get_alignment(self->hal_flash_bank_context); 103 uint32_t lower_bits = size & (aligment - 1); 104 uint32_t size_aligned = size - lower_bits; 105 if (size_aligned){ 106 self->hal_flash_bank_impl->read(self->hal_flash_bank_context, bank, offset, buffer, size_aligned); 107 buffer += size_aligned; 108 offset += size_aligned; 109 size -= size_aligned; 110 } 111 112 // read last part 113 if (size == 0) return; 114 uint8_t aligment_block[BTSTACK_FLASH_ALIGNMENT_MAX]; 115 self->hal_flash_bank_impl->read(self->hal_flash_bank_context, bank, offset, aligment_block, aligment); 116 uint32_t bytes_to_copy = btstack_min(aligment - lower_bits, size); 117 memcpy(buffer, aligment_block, bytes_to_copy); 118 } 119 120 static void btstack_tlv_flash_bank_write(btstack_tlv_flash_bank_t * self, int bank, uint32_t offset, const uint8_t * buffer, uint32_t size){ 121 122 // write main data 123 uint32_t aligment = self->hal_flash_bank_impl->get_alignment(self->hal_flash_bank_context); 124 uint32_t lower_bits = size & (aligment - 1); 125 uint32_t size_aligned = size - lower_bits; 126 if (size_aligned){ 127 self->hal_flash_bank_impl->write(self->hal_flash_bank_context, bank, offset, buffer, size_aligned); 128 buffer += size_aligned; 129 offset += size_aligned; 130 size -= size_aligned; 131 } 132 133 // write last part 134 if (size == 0) return; 135 uint8_t aligment_block[BTSTACK_FLASH_ALIGNMENT_MAX]; 136 memset(aligment_block, 0xff, aligment); 137 memcpy(aligment_block, buffer, lower_bits); 138 self->hal_flash_bank_impl->write(self->hal_flash_bank_context, bank, offset, aligment_block, aligment); 139 } 140 141 142 // iterator 143 144 static void btstack_tlv_flash_bank_iterator_fetch_tag_len(btstack_tlv_flash_bank_t * self, tlv_iterator_t * it){ 145 // abort if header doesn't fit into remaining space 146 if (it->offset + 8 + self->delete_tag_len >= self->hal_flash_bank_impl->get_size(self->hal_flash_bank_context)){ 147 it->tag = 0xffffffff; 148 return; 149 } 150 151 uint8_t entry[8]; 152 btstack_tlv_flash_bank_read(self, it->bank, it->offset, entry, 8); 153 it->tag = big_endian_read_32(entry, 0); 154 it->len = big_endian_read_32(entry, 4); 155 156 #ifdef ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 157 // clear tag, if delete field is set 158 uint32_t delete_tag; 159 btstack_tlv_flash_bank_read(self, it->bank, it->offset + 8, (uint8_t *) &delete_tag, 4); 160 if (delete_tag == 0){ 161 it->tag = 0; 162 } 163 #endif 164 } 165 166 static void btstack_tlv_flash_bank_iterator_init(btstack_tlv_flash_bank_t * self, tlv_iterator_t * it, int bank){ 167 memset(it, 0, sizeof(tlv_iterator_t)); 168 it->bank = bank; 169 it->offset = BTSTACK_TLV_HEADER_LEN; 170 it->size = self->hal_flash_bank_impl->get_size(self->hal_flash_bank_context); 171 btstack_tlv_flash_bank_iterator_fetch_tag_len(self, it); 172 } 173 174 static bool btstack_tlv_flash_bank_iterator_has_next(btstack_tlv_flash_bank_t * self, tlv_iterator_t * it){ 175 UNUSED(self); 176 return it->tag != 0xffffffff; 177 } 178 179 static void tlv_iterator_fetch_next(btstack_tlv_flash_bank_t * self, tlv_iterator_t * it){ 180 it->offset += 8 + btstack_tlv_flash_bank_align_size(self, it->len); 181 182 #ifdef ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 183 // skip delete field 184 it->offset += self->delete_tag_len; 185 #endif 186 187 if (it->offset >= it->size) { 188 it->tag = 0xffffffff; 189 it->len = 0; 190 return; 191 } 192 btstack_tlv_flash_bank_iterator_fetch_tag_len(self, it); 193 } 194 195 // 196 197 // check both banks for headers and pick the one with the higher epoch % 4 198 // @returns bank or -1 if something is invalid 199 static int btstack_tlv_flash_bank_get_latest_bank(btstack_tlv_flash_bank_t * self){ 200 uint8_t header0[BTSTACK_TLV_HEADER_LEN]; 201 uint8_t header1[BTSTACK_TLV_HEADER_LEN]; 202 btstack_tlv_flash_bank_read(self, 0, 0, &header0[0], BTSTACK_TLV_HEADER_LEN); 203 btstack_tlv_flash_bank_read(self, 1, 0, &header1[0], BTSTACK_TLV_HEADER_LEN); 204 int valid0 = memcmp(header0, btstack_tlv_header_magic, BTSTACK_TLV_HEADER_LEN-1) == 0; 205 int valid1 = memcmp(header1, btstack_tlv_header_magic, BTSTACK_TLV_HEADER_LEN-1) == 0; 206 if (!valid0 && !valid1) return -1; 207 if ( valid0 && !valid1) return 0; 208 if (!valid0 && valid1) return 1; 209 int epoch0 = header0[BTSTACK_TLV_HEADER_LEN-1] & 0x03; 210 int epoch1 = header1[BTSTACK_TLV_HEADER_LEN-1] & 0x03; 211 if (epoch0 == ((epoch1 + 1) & 0x03)) return 0; 212 if (epoch1 == ((epoch0 + 1) & 0x03)) return 1; 213 return -1; // invalid, must not happen 214 } 215 216 static void btstack_tlv_flash_bank_write_header(btstack_tlv_flash_bank_t * self, int bank, int epoch){ 217 uint8_t header[BTSTACK_TLV_HEADER_LEN]; 218 memcpy(&header[0], btstack_tlv_header_magic, BTSTACK_TLV_HEADER_LEN-1); 219 header[BTSTACK_TLV_HEADER_LEN-1] = epoch; 220 btstack_tlv_flash_bank_write(self, bank, 0, header, BTSTACK_TLV_HEADER_LEN); 221 } 222 223 /** 224 * @brief Check if erased from offset 225 */ 226 static int btstack_tlv_flash_bank_test_erased(btstack_tlv_flash_bank_t * self, int bank, uint32_t offset){ 227 log_info("test erased: bank %u, offset %u", bank, (unsigned int) offset); 228 uint32_t size = self->hal_flash_bank_impl->get_size(self->hal_flash_bank_context); 229 uint8_t buffer[16]; 230 uint8_t empty16[16]; 231 memset(empty16, 0xff, sizeof(empty16)); 232 while (offset < size){ 233 uint32_t copy_size = (offset + sizeof(empty16) < size) ? sizeof(empty16) : (size - offset); 234 btstack_tlv_flash_bank_read(self, bank, offset, buffer, copy_size); 235 if (memcmp(buffer, empty16, copy_size) != 0) { 236 log_info("not erased %x - %x", (unsigned int) offset, (unsigned int) (offset + copy_size)); 237 return 0; 238 } 239 offset += copy_size; 240 } 241 return 1; 242 } 243 244 /** 245 * @brief erase bank (only if not already erased) 246 */ 247 static void btstack_tlv_flash_bank_erase_bank(btstack_tlv_flash_bank_t * self, int bank){ 248 if (btstack_tlv_flash_bank_test_erased(self, bank, 0)){ 249 log_info("bank %u already erased", bank); 250 } else { 251 log_info("bank %u not empty, erase bank", bank); 252 self->hal_flash_bank_impl->erase(self->hal_flash_bank_context, bank); 253 } 254 } 255 256 static void btstack_tlv_flash_bank_migrate(btstack_tlv_flash_bank_t * self){ 257 258 int next_bank = 1 - self->current_bank; 259 log_info("migrate bank %u -> bank %u", self->current_bank, next_bank); 260 // erase bank (if needed) 261 btstack_tlv_flash_bank_erase_bank(self, next_bank); 262 int next_write_pos = 8; 263 264 tlv_iterator_t it; 265 btstack_tlv_flash_bank_iterator_init(self, &it, self->current_bank); 266 while (btstack_tlv_flash_bank_iterator_has_next(self, &it)){ 267 // skip deleted entries 268 if (it.tag) { 269 uint32_t tag_len = it.len; 270 uint32_t tag_index = it.offset; 271 272 bool tag_valid = true; 273 274 #ifdef ENABLE_TLV_FLASH_WRITE_ONCE 275 // search until end for newer entry of same tag 276 tlv_iterator_t it2; 277 memcpy(&it2, &it, sizeof(tlv_iterator_t)); 278 while (btstack_tlv_flash_bank_iterator_has_next(self, &it2)){ 279 if ((it2.offset != it.offset) && (it2.tag == it.tag)){ 280 tag_valid = false; 281 break; 282 } 283 tlv_iterator_fetch_next(self, &it2); 284 } 285 if (tag_valid == false){ 286 log_info("skip pos %u, tag '%x' as newer entry found at %u", (unsigned int) tag_index, (unsigned int) it.tag, 287 (unsigned int) it2.offset); 288 } 289 #endif 290 291 if (tag_valid) { 292 293 log_info("migrate pos %u, tag '%x' len %u -> new pos %u", 294 (unsigned int) tag_index, (unsigned int) it.tag, (unsigned int) tag_len, next_write_pos); 295 296 // copy header 297 uint8_t header_buffer[8]; 298 btstack_tlv_flash_bank_read(self, self->current_bank, tag_index, header_buffer, 8); 299 btstack_tlv_flash_bank_write(self, next_bank, next_write_pos, header_buffer, 8); 300 tag_index += 8; 301 next_write_pos += 8; 302 303 #ifdef ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 304 // skip delete field 305 tag_index += self->delete_tag_len; 306 next_write_pos += self->delete_tag_len; 307 #endif 308 // copy value 309 int bytes_to_copy = tag_len; 310 uint8_t copy_buffer[32]; 311 while (bytes_to_copy) { 312 int bytes_this_iteration = btstack_min(bytes_to_copy, sizeof(copy_buffer)); 313 btstack_tlv_flash_bank_read(self, self->current_bank, tag_index, copy_buffer, bytes_this_iteration); 314 btstack_tlv_flash_bank_write(self, next_bank, next_write_pos, copy_buffer, bytes_this_iteration); 315 tag_index += bytes_this_iteration; 316 next_write_pos += bytes_this_iteration; 317 bytes_to_copy -= bytes_this_iteration; 318 } 319 } 320 } 321 tlv_iterator_fetch_next(self, &it); 322 } 323 324 // prepare new one 325 uint8_t epoch_buffer; 326 btstack_tlv_flash_bank_read(self, self->current_bank, BTSTACK_TLV_HEADER_LEN-1, &epoch_buffer, 1); 327 btstack_tlv_flash_bank_write_header(self, next_bank, (epoch_buffer + 1) & 3); 328 self->current_bank = next_bank; 329 self->write_offset = next_write_pos; 330 } 331 332 #ifndef ENABLE_TLV_FLASH_WRITE_ONCE 333 static void btstack_tlv_flash_bank_delete_tag_until_offset(btstack_tlv_flash_bank_t * self, uint32_t tag, uint32_t offset){ 334 tlv_iterator_t it; 335 btstack_tlv_flash_bank_iterator_init(self, &it, self->current_bank); 336 while (btstack_tlv_flash_bank_iterator_has_next(self, &it) && it.offset < offset){ 337 if (it.tag == tag){ 338 log_info("Erase tag '%x' at position %u", (unsigned int) tag, (unsigned int) it.offset); 339 340 // mark entry as invalid 341 uint32_t zero_value = 0; 342 #ifdef ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 343 // write delete field at offset 8 344 btstack_tlv_flash_bank_write(self, self->current_bank, it.offset+8, (uint8_t*) &zero_value, sizeof(zero_value)); 345 #else 346 // overwrite tag with zero value 347 btstack_tlv_flash_bank_write(self, self->current_bank, it.offset, (uint8_t*) &zero_value, sizeof(zero_value)); 348 #endif 349 350 } 351 tlv_iterator_fetch_next(self, &it); 352 } 353 } 354 #endif 355 356 /** 357 * Get Value for Tag 358 * @param tag 359 * @param buffer 360 * @param buffer_size 361 * @returns size of value 362 */ 363 static int btstack_tlv_flash_bank_get_tag(void * context, uint32_t tag, uint8_t * buffer, uint32_t buffer_size){ 364 365 btstack_tlv_flash_bank_t * self = (btstack_tlv_flash_bank_t *) context; 366 367 uint32_t tag_index = 0; 368 uint32_t tag_len = 0; 369 tlv_iterator_t it; 370 btstack_tlv_flash_bank_iterator_init(self, &it, self->current_bank); 371 while (btstack_tlv_flash_bank_iterator_has_next(self, &it)){ 372 if (it.tag == tag){ 373 log_info("Found tag '%x' at position %u", (unsigned int) tag, (unsigned int) it.offset); 374 tag_index = it.offset; 375 tag_len = it.len; 376 #ifndef ENABLE_TLV_FLASH_WRITE_ONCE 377 break; 378 #endif 379 } 380 tlv_iterator_fetch_next(self, &it); 381 } 382 if (tag_index == 0) return 0; 383 if (!buffer) return tag_len; 384 int copy_size = btstack_min(buffer_size, tag_len); 385 uint32_t value_offset = tag_index + 8; 386 #ifdef ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 387 // skip delete field 388 value_offset += self->delete_tag_len; 389 #endif 390 btstack_tlv_flash_bank_read(self, self->current_bank, value_offset, buffer, copy_size); 391 return copy_size; 392 } 393 394 /** 395 * Store Tag 396 * @param tag 397 * @param data 398 * @param data_size 399 */ 400 static int btstack_tlv_flash_bank_store_tag(void * context, uint32_t tag, const uint8_t * data, uint32_t data_size){ 401 402 btstack_tlv_flash_bank_t * self = (btstack_tlv_flash_bank_t *) context; 403 404 // trigger migration if not enough space 405 uint32_t required_space = 8 + self->delete_tag_len + data_size; 406 if (self->write_offset + required_space > self->hal_flash_bank_impl->get_size(self->hal_flash_bank_context)){ 407 btstack_tlv_flash_bank_migrate(self); 408 } 409 410 if (self->write_offset + required_space > self->hal_flash_bank_impl->get_size(self->hal_flash_bank_context)){ 411 log_error("couldn't write entry, not enough space left"); 412 return 2; 413 } 414 415 // prepare entry 416 uint8_t entry[8]; 417 big_endian_store_32(entry, 0, tag); 418 big_endian_store_32(entry, 4, data_size); 419 420 log_info("write '%" PRIx32 "', len %" PRIu32 " at %" PRIx32, tag, data_size, self->write_offset); 421 422 uint32_t value_offset = self->write_offset + 8; 423 #ifdef ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 424 // skip delete field 425 value_offset += self->delete_tag_len; 426 #endif 427 428 // write value first 429 btstack_tlv_flash_bank_write(self, self->current_bank, value_offset, data, data_size); 430 431 // then entry 432 btstack_tlv_flash_bank_write(self, self->current_bank, self->write_offset, entry, sizeof(entry)); 433 434 #ifndef ENABLE_TLV_FLASH_WRITE_ONCE 435 // overwrite old entries (if exists) 436 btstack_tlv_flash_bank_delete_tag_until_offset(self, tag, self->write_offset); 437 #endif 438 439 // done 440 self->write_offset += sizeof(entry) + btstack_tlv_flash_bank_align_size(self, data_size); 441 442 #ifdef ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 443 // skip delete field 444 self->write_offset += self->delete_tag_len; 445 #endif 446 447 return 0; 448 } 449 450 /** 451 * Delete Tag 452 * @param tag 453 */ 454 static void btstack_tlv_flash_bank_delete_tag(void * context, uint32_t tag){ 455 #ifdef ENABLE_TLV_FLASH_WRITE_ONCE 456 btstack_tlv_flash_bank_store_tag(context, tag, NULL, 0); 457 #else 458 btstack_tlv_flash_bank_t * self = (btstack_tlv_flash_bank_t *) context; 459 btstack_tlv_flash_bank_delete_tag_until_offset(self, tag, self->write_offset); 460 #endif 461 } 462 463 static const btstack_tlv_t btstack_tlv_flash_bank = { 464 /* int (*get_tag)(..); */ &btstack_tlv_flash_bank_get_tag, 465 /* int (*store_tag)(..); */ &btstack_tlv_flash_bank_store_tag, 466 /* void (*delete_tag)(v..); */ &btstack_tlv_flash_bank_delete_tag, 467 }; 468 469 /** 470 * Init Tag Length Value Store 471 */ 472 const btstack_tlv_t * btstack_tlv_flash_bank_init_instance(btstack_tlv_flash_bank_t * self, const hal_flash_bank_t * hal_flash_bank_impl, void * hal_flash_bank_context){ 473 474 self->hal_flash_bank_impl = hal_flash_bank_impl; 475 self->hal_flash_bank_context = hal_flash_bank_context; 476 self->delete_tag_len = 0; 477 478 #ifdef ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 479 if (hal_flash_bank_impl->get_alignment(hal_flash_bank_context) > 8){ 480 log_error("Flash alignment > 8 with ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD not supported"); 481 return NULL; 482 } 483 // set delete tag len 484 uint32_t aligment = self->hal_flash_bank_impl->get_alignment(self->hal_flash_bank_context); 485 self->delete_tag_len = (uint8_t) btstack_max(4, aligment); 486 log_info("delete tag len %u", self->delete_tag_len); 487 #endif 488 489 // try to find current bank 490 self->current_bank = btstack_tlv_flash_bank_get_latest_bank(self); 491 log_info("found bank %d", self->current_bank); 492 if (self->current_bank >= 0){ 493 494 // find last entry and write offset 495 tlv_iterator_t it; 496 #ifndef ENABLE_TLV_FLASH_WRITE_ONCE 497 uint32_t last_tag = 0; 498 uint32_t last_offset = 0; 499 #endif 500 btstack_tlv_flash_bank_iterator_init(self, &it, self->current_bank); 501 while (btstack_tlv_flash_bank_iterator_has_next(self, &it)){ 502 #ifndef ENABLE_TLV_FLASH_WRITE_ONCE 503 last_tag = it.tag; 504 last_offset = it.offset; 505 #endif 506 tlv_iterator_fetch_next(self, &it); 507 } 508 self->write_offset = it.offset; 509 510 if (self->write_offset <= self->hal_flash_bank_impl->get_size(self->hal_flash_bank_context)){ 511 512 #ifndef ENABLE_TLV_FLASH_WRITE_ONCE 513 // delete older instances of last_tag 514 // this handles the unlikely case where MCU did reset after new value + header was written but before delete did complete 515 if (last_tag){ 516 btstack_tlv_flash_bank_delete_tag_until_offset(self, last_tag, last_offset); 517 } 518 #endif 519 520 // verify that rest of bank is empty 521 // this handles the unlikely case where MCU did reset after new value was written, but not the tag 522 if (!btstack_tlv_flash_bank_test_erased(self, self->current_bank, self->write_offset)){ 523 log_info("Flash not empty after last found tag -> migrate"); 524 btstack_tlv_flash_bank_migrate(self); 525 } else { 526 log_info("Flash clean after last found tag"); 527 } 528 } else { 529 // failure! 530 self->current_bank = -1; 531 } 532 } 533 534 if (self->current_bank < 0) { 535 btstack_tlv_flash_bank_erase_bank(self, 0); 536 self->current_bank = 0; 537 btstack_tlv_flash_bank_write_header(self, self->current_bank, 0); // epoch = 0; 538 self->write_offset = 8; 539 } 540 541 log_info("write offset %" PRIx32, self->write_offset); 542 return &btstack_tlv_flash_bank; 543 } 544 545