1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Error Location Module 4 * 5 * Copyright (C) 2012 Texas Instruments Incorporated - https://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 * @ecc_steps: ECC steps to assign to config 100 * @ecc_step_size: ECC step size to assign to config 101 * @ecc_syndrome_size: ECC syndrome size to assign to config 102 */ 103 int elm_config(struct device *dev, enum bch_ecc bch_type, 104 int ecc_steps, int ecc_step_size, int ecc_syndrome_size) 105 { 106 u32 reg_val; 107 struct elm_info *info = dev_get_drvdata(dev); 108 109 if (!info) { 110 dev_err(dev, "Unable to configure elm - device not probed?\n"); 111 return -EPROBE_DEFER; 112 } 113 /* ELM cannot detect ECC errors for chunks > 1KB */ 114 if (ecc_step_size > ((ELM_ECC_SIZE + 1) / 2)) { 115 dev_err(dev, "unsupported config ecc-size=%d\n", ecc_step_size); 116 return -EINVAL; 117 } 118 /* ELM support 8 error syndrome process */ 119 if (ecc_steps > ERROR_VECTOR_MAX && ecc_steps % ERROR_VECTOR_MAX) { 120 dev_err(dev, "unsupported config ecc-step=%d\n", ecc_steps); 121 return -EINVAL; 122 } 123 124 reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16); 125 elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val); 126 info->bch_type = bch_type; 127 info->ecc_steps = ecc_steps; 128 info->ecc_syndrome_size = ecc_syndrome_size; 129 130 return 0; 131 } 132 EXPORT_SYMBOL(elm_config); 133 134 /** 135 * elm_configure_page_mode - Enable/Disable page mode 136 * @info: elm info 137 * @index: index number of syndrome fragment vector 138 * @enable: enable/disable flag for page mode 139 * 140 * Enable page mode for syndrome fragment index 141 */ 142 static void elm_configure_page_mode(struct elm_info *info, int index, 143 bool enable) 144 { 145 u32 reg_val; 146 147 reg_val = elm_read_reg(info, ELM_PAGE_CTRL); 148 if (enable) 149 reg_val |= BIT(index); /* enable page mode */ 150 else 151 reg_val &= ~BIT(index); /* disable page mode */ 152 153 elm_write_reg(info, ELM_PAGE_CTRL, reg_val); 154 } 155 156 /** 157 * elm_load_syndrome - Load ELM syndrome reg 158 * @info: elm info 159 * @err_vec: elm error vectors 160 * @ecc: buffer with calculated ecc 161 * 162 * Load syndrome fragment registers with calculated ecc in reverse order. 163 */ 164 static void elm_load_syndrome(struct elm_info *info, 165 struct elm_errorvec *err_vec, u8 *ecc) 166 { 167 int i, offset; 168 u32 val; 169 170 for (i = 0; i < info->ecc_steps; i++) { 171 172 /* Check error reported */ 173 if (err_vec[i].error_reported) { 174 elm_configure_page_mode(info, i, true); 175 offset = ELM_SYNDROME_FRAGMENT_0 + 176 SYNDROME_FRAGMENT_REG_SIZE * i; 177 switch (info->bch_type) { 178 case BCH8_ECC: 179 /* syndrome fragment 0 = ecc[9-12B] */ 180 val = cpu_to_be32(*(u32 *) &ecc[9]); 181 elm_write_reg(info, offset, val); 182 183 /* syndrome fragment 1 = ecc[5-8B] */ 184 offset += 4; 185 val = cpu_to_be32(*(u32 *) &ecc[5]); 186 elm_write_reg(info, offset, val); 187 188 /* syndrome fragment 2 = ecc[1-4B] */ 189 offset += 4; 190 val = cpu_to_be32(*(u32 *) &ecc[1]); 191 elm_write_reg(info, offset, val); 192 193 /* syndrome fragment 3 = ecc[0B] */ 194 offset += 4; 195 val = ecc[0]; 196 elm_write_reg(info, offset, val); 197 break; 198 case BCH4_ECC: 199 /* syndrome fragment 0 = ecc[20-52b] bits */ 200 val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) | 201 ((ecc[2] & 0xf) << 28); 202 elm_write_reg(info, offset, val); 203 204 /* syndrome fragment 1 = ecc[0-20b] bits */ 205 offset += 4; 206 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12; 207 elm_write_reg(info, offset, val); 208 break; 209 case BCH16_ECC: 210 val = cpu_to_be32(*(u32 *) &ecc[22]); 211 elm_write_reg(info, offset, val); 212 offset += 4; 213 val = cpu_to_be32(*(u32 *) &ecc[18]); 214 elm_write_reg(info, offset, val); 215 offset += 4; 216 val = cpu_to_be32(*(u32 *) &ecc[14]); 217 elm_write_reg(info, offset, val); 218 offset += 4; 219 val = cpu_to_be32(*(u32 *) &ecc[10]); 220 elm_write_reg(info, offset, val); 221 offset += 4; 222 val = cpu_to_be32(*(u32 *) &ecc[6]); 223 elm_write_reg(info, offset, val); 224 offset += 4; 225 val = cpu_to_be32(*(u32 *) &ecc[2]); 226 elm_write_reg(info, offset, val); 227 offset += 4; 228 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 16; 229 elm_write_reg(info, offset, val); 230 break; 231 default: 232 pr_err("invalid config bch_type\n"); 233 } 234 } 235 236 /* Update ecc pointer with ecc byte size */ 237 ecc += info->ecc_syndrome_size; 238 } 239 } 240 241 /** 242 * elm_start_processing - start elm syndrome processing 243 * @info: elm info 244 * @err_vec: elm error vectors 245 * 246 * Set syndrome valid bit for syndrome fragment registers for which 247 * elm syndrome fragment registers are loaded. This enables elm module 248 * to start processing syndrome vectors. 249 */ 250 static void elm_start_processing(struct elm_info *info, 251 struct elm_errorvec *err_vec) 252 { 253 int i, offset; 254 u32 reg_val; 255 256 /* 257 * Set syndrome vector valid, so that ELM module 258 * will process it for vectors error is reported 259 */ 260 for (i = 0; i < info->ecc_steps; i++) { 261 if (err_vec[i].error_reported) { 262 offset = ELM_SYNDROME_FRAGMENT_6 + 263 SYNDROME_FRAGMENT_REG_SIZE * i; 264 reg_val = elm_read_reg(info, offset); 265 reg_val |= ELM_SYNDROME_VALID; 266 elm_write_reg(info, offset, reg_val); 267 } 268 } 269 } 270 271 /** 272 * elm_error_correction - locate correctable error position 273 * @info: elm info 274 * @err_vec: elm error vectors 275 * 276 * On completion of processing by elm module, error location status 277 * register updated with correctable/uncorrectable error information. 278 * In case of correctable errors, number of errors located from 279 * elm location status register & read the positions from 280 * elm error location register. 281 */ 282 static void elm_error_correction(struct elm_info *info, 283 struct elm_errorvec *err_vec) 284 { 285 int i, j; 286 int offset; 287 u32 reg_val; 288 289 for (i = 0; i < info->ecc_steps; i++) { 290 291 /* Check error reported */ 292 if (err_vec[i].error_reported) { 293 offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i; 294 reg_val = elm_read_reg(info, offset); 295 296 /* Check correctable error or not */ 297 if (reg_val & ECC_CORRECTABLE_MASK) { 298 offset = ELM_ERROR_LOCATION_0 + 299 ERROR_LOCATION_SIZE * i; 300 301 /* Read count of correctable errors */ 302 err_vec[i].error_count = reg_val & 303 ECC_NB_ERRORS_MASK; 304 305 /* Update the error locations in error vector */ 306 for (j = 0; j < err_vec[i].error_count; j++) { 307 308 reg_val = elm_read_reg(info, offset); 309 err_vec[i].error_loc[j] = reg_val & 310 ECC_ERROR_LOCATION_MASK; 311 312 /* Update error location register */ 313 offset += 4; 314 } 315 } else { 316 err_vec[i].error_uncorrectable = true; 317 } 318 319 /* Clearing interrupts for processed error vectors */ 320 elm_write_reg(info, ELM_IRQSTATUS, BIT(i)); 321 322 /* Disable page mode */ 323 elm_configure_page_mode(info, i, false); 324 } 325 } 326 } 327 328 /** 329 * elm_decode_bch_error_page - Locate error position 330 * @dev: device pointer 331 * @ecc_calc: calculated ECC bytes from GPMC 332 * @err_vec: elm error vectors 333 * 334 * Called with one or more error reported vectors & vectors with 335 * error reported is updated in err_vec[].error_reported 336 */ 337 void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc, 338 struct elm_errorvec *err_vec) 339 { 340 struct elm_info *info = dev_get_drvdata(dev); 341 u32 reg_val; 342 343 /* Enable page mode interrupt */ 344 reg_val = elm_read_reg(info, ELM_IRQSTATUS); 345 elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID); 346 elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK); 347 348 /* Load valid ecc byte to syndrome fragment register */ 349 elm_load_syndrome(info, err_vec, ecc_calc); 350 351 /* Enable syndrome processing for which syndrome fragment is updated */ 352 elm_start_processing(info, err_vec); 353 354 /* Wait for ELM module to finish locating error correction */ 355 wait_for_completion(&info->elm_completion); 356 357 /* Disable page mode interrupt */ 358 reg_val = elm_read_reg(info, ELM_IRQENABLE); 359 elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK); 360 elm_error_correction(info, err_vec); 361 } 362 EXPORT_SYMBOL(elm_decode_bch_error_page); 363 364 static irqreturn_t elm_isr(int this_irq, void *dev_id) 365 { 366 u32 reg_val; 367 struct elm_info *info = dev_id; 368 369 reg_val = elm_read_reg(info, ELM_IRQSTATUS); 370 371 /* All error vectors processed */ 372 if (reg_val & INTR_STATUS_PAGE_VALID) { 373 elm_write_reg(info, ELM_IRQSTATUS, 374 reg_val & INTR_STATUS_PAGE_VALID); 375 complete(&info->elm_completion); 376 return IRQ_HANDLED; 377 } 378 379 return IRQ_NONE; 380 } 381 382 static int elm_probe(struct platform_device *pdev) 383 { 384 int ret = 0; 385 struct elm_info *info; 386 int irq; 387 388 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); 389 if (!info) 390 return -ENOMEM; 391 392 info->dev = &pdev->dev; 393 394 irq = platform_get_irq(pdev, 0); 395 if (irq < 0) 396 return irq; 397 398 info->elm_base = devm_platform_ioremap_resource(pdev, 0); 399 if (IS_ERR(info->elm_base)) 400 return PTR_ERR(info->elm_base); 401 402 ret = devm_request_irq(&pdev->dev, irq, elm_isr, 0, 403 pdev->name, info); 404 if (ret) { 405 dev_err(&pdev->dev, "failure requesting %d\n", irq); 406 return ret; 407 } 408 409 pm_runtime_enable(&pdev->dev); 410 if (pm_runtime_get_sync(&pdev->dev) < 0) { 411 ret = -EINVAL; 412 pm_runtime_put_sync(&pdev->dev); 413 pm_runtime_disable(&pdev->dev); 414 dev_err(&pdev->dev, "can't enable clock\n"); 415 return ret; 416 } 417 418 init_completion(&info->elm_completion); 419 INIT_LIST_HEAD(&info->list); 420 list_add(&info->list, &elm_devices); 421 platform_set_drvdata(pdev, info); 422 return ret; 423 } 424 425 static void elm_remove(struct platform_device *pdev) 426 { 427 pm_runtime_put_sync(&pdev->dev); 428 pm_runtime_disable(&pdev->dev); 429 } 430 431 #ifdef CONFIG_PM_SLEEP 432 /* 433 * elm_context_save 434 * saves ELM configurations to preserve them across Hardware powered-down 435 */ 436 static int elm_context_save(struct elm_info *info) 437 { 438 struct elm_registers *regs = &info->elm_regs; 439 enum bch_ecc bch_type = info->bch_type; 440 u32 offset = 0, i; 441 442 regs->elm_irqenable = elm_read_reg(info, ELM_IRQENABLE); 443 regs->elm_sysconfig = elm_read_reg(info, ELM_SYSCONFIG); 444 regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG); 445 regs->elm_page_ctrl = elm_read_reg(info, ELM_PAGE_CTRL); 446 for (i = 0; i < ERROR_VECTOR_MAX; i++) { 447 offset = i * SYNDROME_FRAGMENT_REG_SIZE; 448 switch (bch_type) { 449 case BCH16_ECC: 450 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info, 451 ELM_SYNDROME_FRAGMENT_6 + offset); 452 regs->elm_syndrome_fragment_5[i] = elm_read_reg(info, 453 ELM_SYNDROME_FRAGMENT_5 + offset); 454 regs->elm_syndrome_fragment_4[i] = elm_read_reg(info, 455 ELM_SYNDROME_FRAGMENT_4 + offset); 456 fallthrough; 457 case BCH8_ECC: 458 regs->elm_syndrome_fragment_3[i] = elm_read_reg(info, 459 ELM_SYNDROME_FRAGMENT_3 + offset); 460 regs->elm_syndrome_fragment_2[i] = elm_read_reg(info, 461 ELM_SYNDROME_FRAGMENT_2 + offset); 462 fallthrough; 463 case BCH4_ECC: 464 regs->elm_syndrome_fragment_1[i] = elm_read_reg(info, 465 ELM_SYNDROME_FRAGMENT_1 + offset); 466 regs->elm_syndrome_fragment_0[i] = elm_read_reg(info, 467 ELM_SYNDROME_FRAGMENT_0 + offset); 468 break; 469 default: 470 return -EINVAL; 471 } 472 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs 473 * to be saved for all BCH schemes*/ 474 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info, 475 ELM_SYNDROME_FRAGMENT_6 + offset); 476 } 477 return 0; 478 } 479 480 /* 481 * elm_context_restore 482 * writes configurations saved duing power-down back into ELM registers 483 */ 484 static int elm_context_restore(struct elm_info *info) 485 { 486 struct elm_registers *regs = &info->elm_regs; 487 enum bch_ecc bch_type = info->bch_type; 488 u32 offset = 0, i; 489 490 elm_write_reg(info, ELM_IRQENABLE, regs->elm_irqenable); 491 elm_write_reg(info, ELM_SYSCONFIG, regs->elm_sysconfig); 492 elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config); 493 elm_write_reg(info, ELM_PAGE_CTRL, regs->elm_page_ctrl); 494 for (i = 0; i < ERROR_VECTOR_MAX; i++) { 495 offset = i * SYNDROME_FRAGMENT_REG_SIZE; 496 switch (bch_type) { 497 case BCH16_ECC: 498 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset, 499 regs->elm_syndrome_fragment_6[i]); 500 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset, 501 regs->elm_syndrome_fragment_5[i]); 502 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset, 503 regs->elm_syndrome_fragment_4[i]); 504 fallthrough; 505 case BCH8_ECC: 506 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset, 507 regs->elm_syndrome_fragment_3[i]); 508 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset, 509 regs->elm_syndrome_fragment_2[i]); 510 fallthrough; 511 case BCH4_ECC: 512 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset, 513 regs->elm_syndrome_fragment_1[i]); 514 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset, 515 regs->elm_syndrome_fragment_0[i]); 516 break; 517 default: 518 return -EINVAL; 519 } 520 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */ 521 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset, 522 regs->elm_syndrome_fragment_6[i] & 523 ELM_SYNDROME_VALID); 524 } 525 return 0; 526 } 527 528 static int elm_suspend(struct device *dev) 529 { 530 struct elm_info *info = dev_get_drvdata(dev); 531 elm_context_save(info); 532 pm_runtime_put_sync(dev); 533 return 0; 534 } 535 536 static int elm_resume(struct device *dev) 537 { 538 struct elm_info *info = dev_get_drvdata(dev); 539 pm_runtime_get_sync(dev); 540 elm_context_restore(info); 541 return 0; 542 } 543 #endif 544 545 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume); 546 547 #ifdef CONFIG_OF 548 static const struct of_device_id elm_of_match[] = { 549 { .compatible = "ti,am3352-elm" }, 550 { .compatible = "ti,am64-elm" }, 551 {}, 552 }; 553 MODULE_DEVICE_TABLE(of, elm_of_match); 554 #endif 555 556 static struct platform_driver elm_driver = { 557 .driver = { 558 .name = DRIVER_NAME, 559 .of_match_table = of_match_ptr(elm_of_match), 560 .pm = &elm_pm_ops, 561 }, 562 .probe = elm_probe, 563 .remove_new = elm_remove, 564 }; 565 566 module_platform_driver(elm_driver); 567 568 MODULE_DESCRIPTION("ELM driver for BCH error correction"); 569 MODULE_AUTHOR("Texas Instruments"); 570 MODULE_ALIAS("platform:" DRIVER_NAME); 571 MODULE_LICENSE("GPL v2"); 572