1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Error Location Module 4 * 5 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ 6 */ 7 8 #define DRIVER_NAME "omap-elm" 9 10 #include <linux/platform_device.h> 11 #include <linux/module.h> 12 #include <linux/interrupt.h> 13 #include <linux/io.h> 14 #include <linux/of.h> 15 #include <linux/sched.h> 16 #include <linux/pm_runtime.h> 17 #include <linux/platform_data/elm.h> 18 19 #define ELM_SYSCONFIG 0x010 20 #define ELM_IRQSTATUS 0x018 21 #define ELM_IRQENABLE 0x01c 22 #define ELM_LOCATION_CONFIG 0x020 23 #define ELM_PAGE_CTRL 0x080 24 #define ELM_SYNDROME_FRAGMENT_0 0x400 25 #define ELM_SYNDROME_FRAGMENT_1 0x404 26 #define ELM_SYNDROME_FRAGMENT_2 0x408 27 #define ELM_SYNDROME_FRAGMENT_3 0x40c 28 #define ELM_SYNDROME_FRAGMENT_4 0x410 29 #define ELM_SYNDROME_FRAGMENT_5 0x414 30 #define ELM_SYNDROME_FRAGMENT_6 0x418 31 #define ELM_LOCATION_STATUS 0x800 32 #define ELM_ERROR_LOCATION_0 0x880 33 34 /* ELM Interrupt Status Register */ 35 #define INTR_STATUS_PAGE_VALID BIT(8) 36 37 /* ELM Interrupt Enable Register */ 38 #define INTR_EN_PAGE_MASK BIT(8) 39 40 /* ELM Location Configuration Register */ 41 #define ECC_BCH_LEVEL_MASK 0x3 42 43 /* ELM syndrome */ 44 #define ELM_SYNDROME_VALID BIT(16) 45 46 /* ELM_LOCATION_STATUS Register */ 47 #define ECC_CORRECTABLE_MASK BIT(8) 48 #define ECC_NB_ERRORS_MASK 0x1f 49 50 /* ELM_ERROR_LOCATION_0-15 Registers */ 51 #define ECC_ERROR_LOCATION_MASK 0x1fff 52 53 #define ELM_ECC_SIZE 0x7ff 54 55 #define SYNDROME_FRAGMENT_REG_SIZE 0x40 56 #define ERROR_LOCATION_SIZE 0x100 57 58 struct elm_registers { 59 u32 elm_irqenable; 60 u32 elm_sysconfig; 61 u32 elm_location_config; 62 u32 elm_page_ctrl; 63 u32 elm_syndrome_fragment_6[ERROR_VECTOR_MAX]; 64 u32 elm_syndrome_fragment_5[ERROR_VECTOR_MAX]; 65 u32 elm_syndrome_fragment_4[ERROR_VECTOR_MAX]; 66 u32 elm_syndrome_fragment_3[ERROR_VECTOR_MAX]; 67 u32 elm_syndrome_fragment_2[ERROR_VECTOR_MAX]; 68 u32 elm_syndrome_fragment_1[ERROR_VECTOR_MAX]; 69 u32 elm_syndrome_fragment_0[ERROR_VECTOR_MAX]; 70 }; 71 72 struct elm_info { 73 struct device *dev; 74 void __iomem *elm_base; 75 struct completion elm_completion; 76 struct list_head list; 77 enum bch_ecc bch_type; 78 struct elm_registers elm_regs; 79 int ecc_steps; 80 int ecc_syndrome_size; 81 }; 82 83 static LIST_HEAD(elm_devices); 84 85 static void elm_write_reg(struct elm_info *info, int offset, u32 val) 86 { 87 writel(val, info->elm_base + offset); 88 } 89 90 static u32 elm_read_reg(struct elm_info *info, int offset) 91 { 92 return readl(info->elm_base + offset); 93 } 94 95 /** 96 * elm_config - Configure ELM module 97 * @dev: ELM device 98 * @bch_type: Type of BCH ecc 99 */ 100 int elm_config(struct device *dev, enum bch_ecc bch_type, 101 int ecc_steps, int ecc_step_size, int ecc_syndrome_size) 102 { 103 u32 reg_val; 104 struct elm_info *info = dev_get_drvdata(dev); 105 106 if (!info) { 107 dev_err(dev, "Unable to configure elm - device not probed?\n"); 108 return -EPROBE_DEFER; 109 } 110 /* ELM cannot detect ECC errors for chunks > 1KB */ 111 if (ecc_step_size > ((ELM_ECC_SIZE + 1) / 2)) { 112 dev_err(dev, "unsupported config ecc-size=%d\n", ecc_step_size); 113 return -EINVAL; 114 } 115 /* ELM support 8 error syndrome process */ 116 if (ecc_steps > ERROR_VECTOR_MAX) { 117 dev_err(dev, "unsupported config ecc-step=%d\n", ecc_steps); 118 return -EINVAL; 119 } 120 121 reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16); 122 elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val); 123 info->bch_type = bch_type; 124 info->ecc_steps = ecc_steps; 125 info->ecc_syndrome_size = ecc_syndrome_size; 126 127 return 0; 128 } 129 EXPORT_SYMBOL(elm_config); 130 131 /** 132 * elm_configure_page_mode - Enable/Disable page mode 133 * @info: elm info 134 * @index: index number of syndrome fragment vector 135 * @enable: enable/disable flag for page mode 136 * 137 * Enable page mode for syndrome fragment index 138 */ 139 static void elm_configure_page_mode(struct elm_info *info, int index, 140 bool enable) 141 { 142 u32 reg_val; 143 144 reg_val = elm_read_reg(info, ELM_PAGE_CTRL); 145 if (enable) 146 reg_val |= BIT(index); /* enable page mode */ 147 else 148 reg_val &= ~BIT(index); /* disable page mode */ 149 150 elm_write_reg(info, ELM_PAGE_CTRL, reg_val); 151 } 152 153 /** 154 * elm_load_syndrome - Load ELM syndrome reg 155 * @info: elm info 156 * @err_vec: elm error vectors 157 * @ecc: buffer with calculated ecc 158 * 159 * Load syndrome fragment registers with calculated ecc in reverse order. 160 */ 161 static void elm_load_syndrome(struct elm_info *info, 162 struct elm_errorvec *err_vec, u8 *ecc) 163 { 164 int i, offset; 165 u32 val; 166 167 for (i = 0; i < info->ecc_steps; i++) { 168 169 /* Check error reported */ 170 if (err_vec[i].error_reported) { 171 elm_configure_page_mode(info, i, true); 172 offset = ELM_SYNDROME_FRAGMENT_0 + 173 SYNDROME_FRAGMENT_REG_SIZE * i; 174 switch (info->bch_type) { 175 case BCH8_ECC: 176 /* syndrome fragment 0 = ecc[9-12B] */ 177 val = cpu_to_be32(*(u32 *) &ecc[9]); 178 elm_write_reg(info, offset, val); 179 180 /* syndrome fragment 1 = ecc[5-8B] */ 181 offset += 4; 182 val = cpu_to_be32(*(u32 *) &ecc[5]); 183 elm_write_reg(info, offset, val); 184 185 /* syndrome fragment 2 = ecc[1-4B] */ 186 offset += 4; 187 val = cpu_to_be32(*(u32 *) &ecc[1]); 188 elm_write_reg(info, offset, val); 189 190 /* syndrome fragment 3 = ecc[0B] */ 191 offset += 4; 192 val = ecc[0]; 193 elm_write_reg(info, offset, val); 194 break; 195 case BCH4_ECC: 196 /* syndrome fragment 0 = ecc[20-52b] bits */ 197 val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) | 198 ((ecc[2] & 0xf) << 28); 199 elm_write_reg(info, offset, val); 200 201 /* syndrome fragment 1 = ecc[0-20b] bits */ 202 offset += 4; 203 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12; 204 elm_write_reg(info, offset, val); 205 break; 206 case BCH16_ECC: 207 val = cpu_to_be32(*(u32 *) &ecc[22]); 208 elm_write_reg(info, offset, val); 209 offset += 4; 210 val = cpu_to_be32(*(u32 *) &ecc[18]); 211 elm_write_reg(info, offset, val); 212 offset += 4; 213 val = cpu_to_be32(*(u32 *) &ecc[14]); 214 elm_write_reg(info, offset, val); 215 offset += 4; 216 val = cpu_to_be32(*(u32 *) &ecc[10]); 217 elm_write_reg(info, offset, val); 218 offset += 4; 219 val = cpu_to_be32(*(u32 *) &ecc[6]); 220 elm_write_reg(info, offset, val); 221 offset += 4; 222 val = cpu_to_be32(*(u32 *) &ecc[2]); 223 elm_write_reg(info, offset, val); 224 offset += 4; 225 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 16; 226 elm_write_reg(info, offset, val); 227 break; 228 default: 229 pr_err("invalid config bch_type\n"); 230 } 231 } 232 233 /* Update ecc pointer with ecc byte size */ 234 ecc += info->ecc_syndrome_size; 235 } 236 } 237 238 /** 239 * elm_start_processing - start elm syndrome processing 240 * @info: elm info 241 * @err_vec: elm error vectors 242 * 243 * Set syndrome valid bit for syndrome fragment registers for which 244 * elm syndrome fragment registers are loaded. This enables elm module 245 * to start processing syndrome vectors. 246 */ 247 static void elm_start_processing(struct elm_info *info, 248 struct elm_errorvec *err_vec) 249 { 250 int i, offset; 251 u32 reg_val; 252 253 /* 254 * Set syndrome vector valid, so that ELM module 255 * will process it for vectors error is reported 256 */ 257 for (i = 0; i < info->ecc_steps; i++) { 258 if (err_vec[i].error_reported) { 259 offset = ELM_SYNDROME_FRAGMENT_6 + 260 SYNDROME_FRAGMENT_REG_SIZE * i; 261 reg_val = elm_read_reg(info, offset); 262 reg_val |= ELM_SYNDROME_VALID; 263 elm_write_reg(info, offset, reg_val); 264 } 265 } 266 } 267 268 /** 269 * elm_error_correction - locate correctable error position 270 * @info: elm info 271 * @err_vec: elm error vectors 272 * 273 * On completion of processing by elm module, error location status 274 * register updated with correctable/uncorrectable error information. 275 * In case of correctable errors, number of errors located from 276 * elm location status register & read the positions from 277 * elm error location register. 278 */ 279 static void elm_error_correction(struct elm_info *info, 280 struct elm_errorvec *err_vec) 281 { 282 int i, j, errors = 0; 283 int offset; 284 u32 reg_val; 285 286 for (i = 0; i < info->ecc_steps; i++) { 287 288 /* Check error reported */ 289 if (err_vec[i].error_reported) { 290 offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i; 291 reg_val = elm_read_reg(info, offset); 292 293 /* Check correctable error or not */ 294 if (reg_val & ECC_CORRECTABLE_MASK) { 295 offset = ELM_ERROR_LOCATION_0 + 296 ERROR_LOCATION_SIZE * i; 297 298 /* Read count of correctable errors */ 299 err_vec[i].error_count = reg_val & 300 ECC_NB_ERRORS_MASK; 301 302 /* Update the error locations in error vector */ 303 for (j = 0; j < err_vec[i].error_count; j++) { 304 305 reg_val = elm_read_reg(info, offset); 306 err_vec[i].error_loc[j] = reg_val & 307 ECC_ERROR_LOCATION_MASK; 308 309 /* Update error location register */ 310 offset += 4; 311 } 312 313 errors += err_vec[i].error_count; 314 } else { 315 err_vec[i].error_uncorrectable = true; 316 } 317 318 /* Clearing interrupts for processed error vectors */ 319 elm_write_reg(info, ELM_IRQSTATUS, BIT(i)); 320 321 /* Disable page mode */ 322 elm_configure_page_mode(info, i, false); 323 } 324 } 325 } 326 327 /** 328 * elm_decode_bch_error_page - Locate error position 329 * @dev: device pointer 330 * @ecc_calc: calculated ECC bytes from GPMC 331 * @err_vec: elm error vectors 332 * 333 * Called with one or more error reported vectors & vectors with 334 * error reported is updated in err_vec[].error_reported 335 */ 336 void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc, 337 struct elm_errorvec *err_vec) 338 { 339 struct elm_info *info = dev_get_drvdata(dev); 340 u32 reg_val; 341 342 /* Enable page mode interrupt */ 343 reg_val = elm_read_reg(info, ELM_IRQSTATUS); 344 elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID); 345 elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK); 346 347 /* Load valid ecc byte to syndrome fragment register */ 348 elm_load_syndrome(info, err_vec, ecc_calc); 349 350 /* Enable syndrome processing for which syndrome fragment is updated */ 351 elm_start_processing(info, err_vec); 352 353 /* Wait for ELM module to finish locating error correction */ 354 wait_for_completion(&info->elm_completion); 355 356 /* Disable page mode interrupt */ 357 reg_val = elm_read_reg(info, ELM_IRQENABLE); 358 elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK); 359 elm_error_correction(info, err_vec); 360 } 361 EXPORT_SYMBOL(elm_decode_bch_error_page); 362 363 static irqreturn_t elm_isr(int this_irq, void *dev_id) 364 { 365 u32 reg_val; 366 struct elm_info *info = dev_id; 367 368 reg_val = elm_read_reg(info, ELM_IRQSTATUS); 369 370 /* All error vectors processed */ 371 if (reg_val & INTR_STATUS_PAGE_VALID) { 372 elm_write_reg(info, ELM_IRQSTATUS, 373 reg_val & INTR_STATUS_PAGE_VALID); 374 complete(&info->elm_completion); 375 return IRQ_HANDLED; 376 } 377 378 return IRQ_NONE; 379 } 380 381 static int elm_probe(struct platform_device *pdev) 382 { 383 int ret = 0; 384 struct resource *res, *irq; 385 struct elm_info *info; 386 387 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); 388 if (!info) 389 return -ENOMEM; 390 391 info->dev = &pdev->dev; 392 393 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 394 if (!irq) { 395 dev_err(&pdev->dev, "no irq resource defined\n"); 396 return -ENODEV; 397 } 398 399 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 400 info->elm_base = devm_ioremap_resource(&pdev->dev, res); 401 if (IS_ERR(info->elm_base)) 402 return PTR_ERR(info->elm_base); 403 404 ret = devm_request_irq(&pdev->dev, irq->start, elm_isr, 0, 405 pdev->name, info); 406 if (ret) { 407 dev_err(&pdev->dev, "failure requesting %pr\n", irq); 408 return ret; 409 } 410 411 pm_runtime_enable(&pdev->dev); 412 if (pm_runtime_get_sync(&pdev->dev) < 0) { 413 ret = -EINVAL; 414 pm_runtime_disable(&pdev->dev); 415 dev_err(&pdev->dev, "can't enable clock\n"); 416 return ret; 417 } 418 419 init_completion(&info->elm_completion); 420 INIT_LIST_HEAD(&info->list); 421 list_add(&info->list, &elm_devices); 422 platform_set_drvdata(pdev, info); 423 return ret; 424 } 425 426 static int elm_remove(struct platform_device *pdev) 427 { 428 pm_runtime_put_sync(&pdev->dev); 429 pm_runtime_disable(&pdev->dev); 430 return 0; 431 } 432 433 #ifdef CONFIG_PM_SLEEP 434 /** 435 * elm_context_save 436 * saves ELM configurations to preserve them across Hardware powered-down 437 */ 438 static int elm_context_save(struct elm_info *info) 439 { 440 struct elm_registers *regs = &info->elm_regs; 441 enum bch_ecc bch_type = info->bch_type; 442 u32 offset = 0, i; 443 444 regs->elm_irqenable = elm_read_reg(info, ELM_IRQENABLE); 445 regs->elm_sysconfig = elm_read_reg(info, ELM_SYSCONFIG); 446 regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG); 447 regs->elm_page_ctrl = elm_read_reg(info, ELM_PAGE_CTRL); 448 for (i = 0; i < ERROR_VECTOR_MAX; i++) { 449 offset = i * SYNDROME_FRAGMENT_REG_SIZE; 450 switch (bch_type) { 451 case BCH16_ECC: 452 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info, 453 ELM_SYNDROME_FRAGMENT_6 + offset); 454 regs->elm_syndrome_fragment_5[i] = elm_read_reg(info, 455 ELM_SYNDROME_FRAGMENT_5 + offset); 456 regs->elm_syndrome_fragment_4[i] = elm_read_reg(info, 457 ELM_SYNDROME_FRAGMENT_4 + offset); 458 fallthrough; 459 case BCH8_ECC: 460 regs->elm_syndrome_fragment_3[i] = elm_read_reg(info, 461 ELM_SYNDROME_FRAGMENT_3 + offset); 462 regs->elm_syndrome_fragment_2[i] = elm_read_reg(info, 463 ELM_SYNDROME_FRAGMENT_2 + offset); 464 fallthrough; 465 case BCH4_ECC: 466 regs->elm_syndrome_fragment_1[i] = elm_read_reg(info, 467 ELM_SYNDROME_FRAGMENT_1 + offset); 468 regs->elm_syndrome_fragment_0[i] = elm_read_reg(info, 469 ELM_SYNDROME_FRAGMENT_0 + offset); 470 break; 471 default: 472 return -EINVAL; 473 } 474 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs 475 * to be saved for all BCH schemes*/ 476 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info, 477 ELM_SYNDROME_FRAGMENT_6 + offset); 478 } 479 return 0; 480 } 481 482 /** 483 * elm_context_restore 484 * writes configurations saved duing power-down back into ELM registers 485 */ 486 static int elm_context_restore(struct elm_info *info) 487 { 488 struct elm_registers *regs = &info->elm_regs; 489 enum bch_ecc bch_type = info->bch_type; 490 u32 offset = 0, i; 491 492 elm_write_reg(info, ELM_IRQENABLE, regs->elm_irqenable); 493 elm_write_reg(info, ELM_SYSCONFIG, regs->elm_sysconfig); 494 elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config); 495 elm_write_reg(info, ELM_PAGE_CTRL, regs->elm_page_ctrl); 496 for (i = 0; i < ERROR_VECTOR_MAX; i++) { 497 offset = i * SYNDROME_FRAGMENT_REG_SIZE; 498 switch (bch_type) { 499 case BCH16_ECC: 500 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset, 501 regs->elm_syndrome_fragment_6[i]); 502 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset, 503 regs->elm_syndrome_fragment_5[i]); 504 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset, 505 regs->elm_syndrome_fragment_4[i]); 506 fallthrough; 507 case BCH8_ECC: 508 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset, 509 regs->elm_syndrome_fragment_3[i]); 510 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset, 511 regs->elm_syndrome_fragment_2[i]); 512 fallthrough; 513 case BCH4_ECC: 514 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset, 515 regs->elm_syndrome_fragment_1[i]); 516 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset, 517 regs->elm_syndrome_fragment_0[i]); 518 break; 519 default: 520 return -EINVAL; 521 } 522 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */ 523 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset, 524 regs->elm_syndrome_fragment_6[i] & 525 ELM_SYNDROME_VALID); 526 } 527 return 0; 528 } 529 530 static int elm_suspend(struct device *dev) 531 { 532 struct elm_info *info = dev_get_drvdata(dev); 533 elm_context_save(info); 534 pm_runtime_put_sync(dev); 535 return 0; 536 } 537 538 static int elm_resume(struct device *dev) 539 { 540 struct elm_info *info = dev_get_drvdata(dev); 541 pm_runtime_get_sync(dev); 542 elm_context_restore(info); 543 return 0; 544 } 545 #endif 546 547 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume); 548 549 #ifdef CONFIG_OF 550 static const struct of_device_id elm_of_match[] = { 551 { .compatible = "ti,am3352-elm" }, 552 {}, 553 }; 554 MODULE_DEVICE_TABLE(of, elm_of_match); 555 #endif 556 557 static struct platform_driver elm_driver = { 558 .driver = { 559 .name = DRIVER_NAME, 560 .of_match_table = of_match_ptr(elm_of_match), 561 .pm = &elm_pm_ops, 562 }, 563 .probe = elm_probe, 564 .remove = elm_remove, 565 }; 566 567 module_platform_driver(elm_driver); 568 569 MODULE_DESCRIPTION("ELM driver for BCH error correction"); 570 MODULE_AUTHOR("Texas Instruments"); 571 MODULE_ALIAS("platform:" DRIVER_NAME); 572 MODULE_LICENSE("GPL v2"); 573