1 /* 2 * Error Location Module 3 * 4 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 */ 17 18 #define DRIVER_NAME "omap-elm" 19 20 #include <linux/platform_device.h> 21 #include <linux/module.h> 22 #include <linux/interrupt.h> 23 #include <linux/io.h> 24 #include <linux/of.h> 25 #include <linux/sched.h> 26 #include <linux/pm_runtime.h> 27 #include <linux/platform_data/elm.h> 28 29 #define ELM_SYSCONFIG 0x010 30 #define ELM_IRQSTATUS 0x018 31 #define ELM_IRQENABLE 0x01c 32 #define ELM_LOCATION_CONFIG 0x020 33 #define ELM_PAGE_CTRL 0x080 34 #define ELM_SYNDROME_FRAGMENT_0 0x400 35 #define ELM_SYNDROME_FRAGMENT_1 0x404 36 #define ELM_SYNDROME_FRAGMENT_2 0x408 37 #define ELM_SYNDROME_FRAGMENT_3 0x40c 38 #define ELM_SYNDROME_FRAGMENT_4 0x410 39 #define ELM_SYNDROME_FRAGMENT_5 0x414 40 #define ELM_SYNDROME_FRAGMENT_6 0x418 41 #define ELM_LOCATION_STATUS 0x800 42 #define ELM_ERROR_LOCATION_0 0x880 43 44 /* ELM Interrupt Status Register */ 45 #define INTR_STATUS_PAGE_VALID BIT(8) 46 47 /* ELM Interrupt Enable Register */ 48 #define INTR_EN_PAGE_MASK BIT(8) 49 50 /* ELM Location Configuration Register */ 51 #define ECC_BCH_LEVEL_MASK 0x3 52 53 /* ELM syndrome */ 54 #define ELM_SYNDROME_VALID BIT(16) 55 56 /* ELM_LOCATION_STATUS Register */ 57 #define ECC_CORRECTABLE_MASK BIT(8) 58 #define ECC_NB_ERRORS_MASK 0x1f 59 60 /* ELM_ERROR_LOCATION_0-15 Registers */ 61 #define ECC_ERROR_LOCATION_MASK 0x1fff 62 63 #define ELM_ECC_SIZE 0x7ff 64 65 #define SYNDROME_FRAGMENT_REG_SIZE 0x40 66 #define ERROR_LOCATION_SIZE 0x100 67 68 struct elm_registers { 69 u32 elm_irqenable; 70 u32 elm_sysconfig; 71 u32 elm_location_config; 72 u32 elm_page_ctrl; 73 u32 elm_syndrome_fragment_6[ERROR_VECTOR_MAX]; 74 u32 elm_syndrome_fragment_5[ERROR_VECTOR_MAX]; 75 u32 elm_syndrome_fragment_4[ERROR_VECTOR_MAX]; 76 u32 elm_syndrome_fragment_3[ERROR_VECTOR_MAX]; 77 u32 elm_syndrome_fragment_2[ERROR_VECTOR_MAX]; 78 u32 elm_syndrome_fragment_1[ERROR_VECTOR_MAX]; 79 u32 elm_syndrome_fragment_0[ERROR_VECTOR_MAX]; 80 }; 81 82 struct elm_info { 83 struct device *dev; 84 void __iomem *elm_base; 85 struct completion elm_completion; 86 struct list_head list; 87 enum bch_ecc bch_type; 88 struct elm_registers elm_regs; 89 int ecc_steps; 90 int ecc_syndrome_size; 91 }; 92 93 static LIST_HEAD(elm_devices); 94 95 static void elm_write_reg(struct elm_info *info, int offset, u32 val) 96 { 97 writel(val, info->elm_base + offset); 98 } 99 100 static u32 elm_read_reg(struct elm_info *info, int offset) 101 { 102 return readl(info->elm_base + offset); 103 } 104 105 /** 106 * elm_config - Configure ELM module 107 * @dev: ELM device 108 * @bch_type: Type of BCH ecc 109 */ 110 int elm_config(struct device *dev, enum bch_ecc bch_type, 111 int ecc_steps, int ecc_step_size, int ecc_syndrome_size) 112 { 113 u32 reg_val; 114 struct elm_info *info = dev_get_drvdata(dev); 115 116 if (!info) { 117 dev_err(dev, "Unable to configure elm - device not probed?\n"); 118 return -EPROBE_DEFER; 119 } 120 /* ELM cannot detect ECC errors for chunks > 1KB */ 121 if (ecc_step_size > ((ELM_ECC_SIZE + 1) / 2)) { 122 dev_err(dev, "unsupported config ecc-size=%d\n", ecc_step_size); 123 return -EINVAL; 124 } 125 /* ELM support 8 error syndrome process */ 126 if (ecc_steps > ERROR_VECTOR_MAX) { 127 dev_err(dev, "unsupported config ecc-step=%d\n", ecc_steps); 128 return -EINVAL; 129 } 130 131 reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16); 132 elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val); 133 info->bch_type = bch_type; 134 info->ecc_steps = ecc_steps; 135 info->ecc_syndrome_size = ecc_syndrome_size; 136 137 return 0; 138 } 139 EXPORT_SYMBOL(elm_config); 140 141 /** 142 * elm_configure_page_mode - Enable/Disable page mode 143 * @info: elm info 144 * @index: index number of syndrome fragment vector 145 * @enable: enable/disable flag for page mode 146 * 147 * Enable page mode for syndrome fragment index 148 */ 149 static void elm_configure_page_mode(struct elm_info *info, int index, 150 bool enable) 151 { 152 u32 reg_val; 153 154 reg_val = elm_read_reg(info, ELM_PAGE_CTRL); 155 if (enable) 156 reg_val |= BIT(index); /* enable page mode */ 157 else 158 reg_val &= ~BIT(index); /* disable page mode */ 159 160 elm_write_reg(info, ELM_PAGE_CTRL, reg_val); 161 } 162 163 /** 164 * elm_load_syndrome - Load ELM syndrome reg 165 * @info: elm info 166 * @err_vec: elm error vectors 167 * @ecc: buffer with calculated ecc 168 * 169 * Load syndrome fragment registers with calculated ecc in reverse order. 170 */ 171 static void elm_load_syndrome(struct elm_info *info, 172 struct elm_errorvec *err_vec, u8 *ecc) 173 { 174 int i, offset; 175 u32 val; 176 177 for (i = 0; i < info->ecc_steps; i++) { 178 179 /* Check error reported */ 180 if (err_vec[i].error_reported) { 181 elm_configure_page_mode(info, i, true); 182 offset = ELM_SYNDROME_FRAGMENT_0 + 183 SYNDROME_FRAGMENT_REG_SIZE * i; 184 switch (info->bch_type) { 185 case BCH8_ECC: 186 /* syndrome fragment 0 = ecc[9-12B] */ 187 val = cpu_to_be32(*(u32 *) &ecc[9]); 188 elm_write_reg(info, offset, val); 189 190 /* syndrome fragment 1 = ecc[5-8B] */ 191 offset += 4; 192 val = cpu_to_be32(*(u32 *) &ecc[5]); 193 elm_write_reg(info, offset, val); 194 195 /* syndrome fragment 2 = ecc[1-4B] */ 196 offset += 4; 197 val = cpu_to_be32(*(u32 *) &ecc[1]); 198 elm_write_reg(info, offset, val); 199 200 /* syndrome fragment 3 = ecc[0B] */ 201 offset += 4; 202 val = ecc[0]; 203 elm_write_reg(info, offset, val); 204 break; 205 case BCH4_ECC: 206 /* syndrome fragment 0 = ecc[20-52b] bits */ 207 val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) | 208 ((ecc[2] & 0xf) << 28); 209 elm_write_reg(info, offset, val); 210 211 /* syndrome fragment 1 = ecc[0-20b] bits */ 212 offset += 4; 213 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12; 214 elm_write_reg(info, offset, val); 215 break; 216 case BCH16_ECC: 217 val = cpu_to_be32(*(u32 *) &ecc[22]); 218 elm_write_reg(info, offset, val); 219 offset += 4; 220 val = cpu_to_be32(*(u32 *) &ecc[18]); 221 elm_write_reg(info, offset, val); 222 offset += 4; 223 val = cpu_to_be32(*(u32 *) &ecc[14]); 224 elm_write_reg(info, offset, val); 225 offset += 4; 226 val = cpu_to_be32(*(u32 *) &ecc[10]); 227 elm_write_reg(info, offset, val); 228 offset += 4; 229 val = cpu_to_be32(*(u32 *) &ecc[6]); 230 elm_write_reg(info, offset, val); 231 offset += 4; 232 val = cpu_to_be32(*(u32 *) &ecc[2]); 233 elm_write_reg(info, offset, val); 234 offset += 4; 235 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 16; 236 elm_write_reg(info, offset, val); 237 break; 238 default: 239 pr_err("invalid config bch_type\n"); 240 } 241 } 242 243 /* Update ecc pointer with ecc byte size */ 244 ecc += info->ecc_syndrome_size; 245 } 246 } 247 248 /** 249 * elm_start_processing - start elm syndrome processing 250 * @info: elm info 251 * @err_vec: elm error vectors 252 * 253 * Set syndrome valid bit for syndrome fragment registers for which 254 * elm syndrome fragment registers are loaded. This enables elm module 255 * to start processing syndrome vectors. 256 */ 257 static void elm_start_processing(struct elm_info *info, 258 struct elm_errorvec *err_vec) 259 { 260 int i, offset; 261 u32 reg_val; 262 263 /* 264 * Set syndrome vector valid, so that ELM module 265 * will process it for vectors error is reported 266 */ 267 for (i = 0; i < info->ecc_steps; i++) { 268 if (err_vec[i].error_reported) { 269 offset = ELM_SYNDROME_FRAGMENT_6 + 270 SYNDROME_FRAGMENT_REG_SIZE * i; 271 reg_val = elm_read_reg(info, offset); 272 reg_val |= ELM_SYNDROME_VALID; 273 elm_write_reg(info, offset, reg_val); 274 } 275 } 276 } 277 278 /** 279 * elm_error_correction - locate correctable error position 280 * @info: elm info 281 * @err_vec: elm error vectors 282 * 283 * On completion of processing by elm module, error location status 284 * register updated with correctable/uncorrectable error information. 285 * In case of correctable errors, number of errors located from 286 * elm location status register & read the positions from 287 * elm error location register. 288 */ 289 static void elm_error_correction(struct elm_info *info, 290 struct elm_errorvec *err_vec) 291 { 292 int i, j, errors = 0; 293 int offset; 294 u32 reg_val; 295 296 for (i = 0; i < info->ecc_steps; i++) { 297 298 /* Check error reported */ 299 if (err_vec[i].error_reported) { 300 offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i; 301 reg_val = elm_read_reg(info, offset); 302 303 /* Check correctable error or not */ 304 if (reg_val & ECC_CORRECTABLE_MASK) { 305 offset = ELM_ERROR_LOCATION_0 + 306 ERROR_LOCATION_SIZE * i; 307 308 /* Read count of correctable errors */ 309 err_vec[i].error_count = reg_val & 310 ECC_NB_ERRORS_MASK; 311 312 /* Update the error locations in error vector */ 313 for (j = 0; j < err_vec[i].error_count; j++) { 314 315 reg_val = elm_read_reg(info, offset); 316 err_vec[i].error_loc[j] = reg_val & 317 ECC_ERROR_LOCATION_MASK; 318 319 /* Update error location register */ 320 offset += 4; 321 } 322 323 errors += err_vec[i].error_count; 324 } else { 325 err_vec[i].error_uncorrectable = true; 326 } 327 328 /* Clearing interrupts for processed error vectors */ 329 elm_write_reg(info, ELM_IRQSTATUS, BIT(i)); 330 331 /* Disable page mode */ 332 elm_configure_page_mode(info, i, false); 333 } 334 } 335 } 336 337 /** 338 * elm_decode_bch_error_page - Locate error position 339 * @dev: device pointer 340 * @ecc_calc: calculated ECC bytes from GPMC 341 * @err_vec: elm error vectors 342 * 343 * Called with one or more error reported vectors & vectors with 344 * error reported is updated in err_vec[].error_reported 345 */ 346 void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc, 347 struct elm_errorvec *err_vec) 348 { 349 struct elm_info *info = dev_get_drvdata(dev); 350 u32 reg_val; 351 352 /* Enable page mode interrupt */ 353 reg_val = elm_read_reg(info, ELM_IRQSTATUS); 354 elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID); 355 elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK); 356 357 /* Load valid ecc byte to syndrome fragment register */ 358 elm_load_syndrome(info, err_vec, ecc_calc); 359 360 /* Enable syndrome processing for which syndrome fragment is updated */ 361 elm_start_processing(info, err_vec); 362 363 /* Wait for ELM module to finish locating error correction */ 364 wait_for_completion(&info->elm_completion); 365 366 /* Disable page mode interrupt */ 367 reg_val = elm_read_reg(info, ELM_IRQENABLE); 368 elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK); 369 elm_error_correction(info, err_vec); 370 } 371 EXPORT_SYMBOL(elm_decode_bch_error_page); 372 373 static irqreturn_t elm_isr(int this_irq, void *dev_id) 374 { 375 u32 reg_val; 376 struct elm_info *info = dev_id; 377 378 reg_val = elm_read_reg(info, ELM_IRQSTATUS); 379 380 /* All error vectors processed */ 381 if (reg_val & INTR_STATUS_PAGE_VALID) { 382 elm_write_reg(info, ELM_IRQSTATUS, 383 reg_val & INTR_STATUS_PAGE_VALID); 384 complete(&info->elm_completion); 385 return IRQ_HANDLED; 386 } 387 388 return IRQ_NONE; 389 } 390 391 static int elm_probe(struct platform_device *pdev) 392 { 393 int ret = 0; 394 struct resource *res, *irq; 395 struct elm_info *info; 396 397 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); 398 if (!info) 399 return -ENOMEM; 400 401 info->dev = &pdev->dev; 402 403 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 404 if (!irq) { 405 dev_err(&pdev->dev, "no irq resource defined\n"); 406 return -ENODEV; 407 } 408 409 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 410 info->elm_base = devm_ioremap_resource(&pdev->dev, res); 411 if (IS_ERR(info->elm_base)) 412 return PTR_ERR(info->elm_base); 413 414 ret = devm_request_irq(&pdev->dev, irq->start, elm_isr, 0, 415 pdev->name, info); 416 if (ret) { 417 dev_err(&pdev->dev, "failure requesting %pr\n", irq); 418 return ret; 419 } 420 421 pm_runtime_enable(&pdev->dev); 422 if (pm_runtime_get_sync(&pdev->dev) < 0) { 423 ret = -EINVAL; 424 pm_runtime_disable(&pdev->dev); 425 dev_err(&pdev->dev, "can't enable clock\n"); 426 return ret; 427 } 428 429 init_completion(&info->elm_completion); 430 INIT_LIST_HEAD(&info->list); 431 list_add(&info->list, &elm_devices); 432 platform_set_drvdata(pdev, info); 433 return ret; 434 } 435 436 static int elm_remove(struct platform_device *pdev) 437 { 438 pm_runtime_put_sync(&pdev->dev); 439 pm_runtime_disable(&pdev->dev); 440 return 0; 441 } 442 443 #ifdef CONFIG_PM_SLEEP 444 /** 445 * elm_context_save 446 * saves ELM configurations to preserve them across Hardware powered-down 447 */ 448 static int elm_context_save(struct elm_info *info) 449 { 450 struct elm_registers *regs = &info->elm_regs; 451 enum bch_ecc bch_type = info->bch_type; 452 u32 offset = 0, i; 453 454 regs->elm_irqenable = elm_read_reg(info, ELM_IRQENABLE); 455 regs->elm_sysconfig = elm_read_reg(info, ELM_SYSCONFIG); 456 regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG); 457 regs->elm_page_ctrl = elm_read_reg(info, ELM_PAGE_CTRL); 458 for (i = 0; i < ERROR_VECTOR_MAX; i++) { 459 offset = i * SYNDROME_FRAGMENT_REG_SIZE; 460 switch (bch_type) { 461 case BCH16_ECC: 462 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info, 463 ELM_SYNDROME_FRAGMENT_6 + offset); 464 regs->elm_syndrome_fragment_5[i] = elm_read_reg(info, 465 ELM_SYNDROME_FRAGMENT_5 + offset); 466 regs->elm_syndrome_fragment_4[i] = elm_read_reg(info, 467 ELM_SYNDROME_FRAGMENT_4 + offset); 468 /* fall through */ 469 case BCH8_ECC: 470 regs->elm_syndrome_fragment_3[i] = elm_read_reg(info, 471 ELM_SYNDROME_FRAGMENT_3 + offset); 472 regs->elm_syndrome_fragment_2[i] = elm_read_reg(info, 473 ELM_SYNDROME_FRAGMENT_2 + offset); 474 /* fall through */ 475 case BCH4_ECC: 476 regs->elm_syndrome_fragment_1[i] = elm_read_reg(info, 477 ELM_SYNDROME_FRAGMENT_1 + offset); 478 regs->elm_syndrome_fragment_0[i] = elm_read_reg(info, 479 ELM_SYNDROME_FRAGMENT_0 + offset); 480 break; 481 default: 482 return -EINVAL; 483 } 484 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs 485 * to be saved for all BCH schemes*/ 486 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info, 487 ELM_SYNDROME_FRAGMENT_6 + offset); 488 } 489 return 0; 490 } 491 492 /** 493 * elm_context_restore 494 * writes configurations saved duing power-down back into ELM registers 495 */ 496 static int elm_context_restore(struct elm_info *info) 497 { 498 struct elm_registers *regs = &info->elm_regs; 499 enum bch_ecc bch_type = info->bch_type; 500 u32 offset = 0, i; 501 502 elm_write_reg(info, ELM_IRQENABLE, regs->elm_irqenable); 503 elm_write_reg(info, ELM_SYSCONFIG, regs->elm_sysconfig); 504 elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config); 505 elm_write_reg(info, ELM_PAGE_CTRL, regs->elm_page_ctrl); 506 for (i = 0; i < ERROR_VECTOR_MAX; i++) { 507 offset = i * SYNDROME_FRAGMENT_REG_SIZE; 508 switch (bch_type) { 509 case BCH16_ECC: 510 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset, 511 regs->elm_syndrome_fragment_6[i]); 512 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset, 513 regs->elm_syndrome_fragment_5[i]); 514 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset, 515 regs->elm_syndrome_fragment_4[i]); 516 /* fall through */ 517 case BCH8_ECC: 518 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset, 519 regs->elm_syndrome_fragment_3[i]); 520 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset, 521 regs->elm_syndrome_fragment_2[i]); 522 /* fall through */ 523 case BCH4_ECC: 524 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset, 525 regs->elm_syndrome_fragment_1[i]); 526 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset, 527 regs->elm_syndrome_fragment_0[i]); 528 break; 529 default: 530 return -EINVAL; 531 } 532 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */ 533 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset, 534 regs->elm_syndrome_fragment_6[i] & 535 ELM_SYNDROME_VALID); 536 } 537 return 0; 538 } 539 540 static int elm_suspend(struct device *dev) 541 { 542 struct elm_info *info = dev_get_drvdata(dev); 543 elm_context_save(info); 544 pm_runtime_put_sync(dev); 545 return 0; 546 } 547 548 static int elm_resume(struct device *dev) 549 { 550 struct elm_info *info = dev_get_drvdata(dev); 551 pm_runtime_get_sync(dev); 552 elm_context_restore(info); 553 return 0; 554 } 555 #endif 556 557 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume); 558 559 #ifdef CONFIG_OF 560 static const struct of_device_id elm_of_match[] = { 561 { .compatible = "ti,am3352-elm" }, 562 {}, 563 }; 564 MODULE_DEVICE_TABLE(of, elm_of_match); 565 #endif 566 567 static struct platform_driver elm_driver = { 568 .driver = { 569 .name = DRIVER_NAME, 570 .of_match_table = of_match_ptr(elm_of_match), 571 .pm = &elm_pm_ops, 572 }, 573 .probe = elm_probe, 574 .remove = elm_remove, 575 }; 576 577 module_platform_driver(elm_driver); 578 579 MODULE_DESCRIPTION("ELM driver for BCH error correction"); 580 MODULE_AUTHOR("Texas Instruments"); 581 MODULE_ALIAS("platform:" DRIVER_NAME); 582 MODULE_LICENSE("GPL v2"); 583