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 58struct 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 72struct 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 83static LIST_HEAD(elm_devices); 84 85static void elm_write_reg(struct elm_info *info, int offset, u32 val) 86{ 87 writel(val, info->elm_base + offset); 88} 89 90static 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 */ 100int 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} 129EXPORT_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 */ 139static 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 */ 161static 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 = (__force u32)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 = (__force u32)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 = (__force u32)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 = ((__force u32)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 = (__force u32)cpu_to_be32(*(u32 *)&ecc[0]) >> 12; 204 elm_write_reg(info, offset, val); 205 break; 206 case BCH16_ECC: 207 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[22]); 208 elm_write_reg(info, offset, val); 209 offset += 4; 210 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[18]); 211 elm_write_reg(info, offset, val); 212 offset += 4; 213 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[14]); 214 elm_write_reg(info, offset, val); 215 offset += 4; 216 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[10]); 217 elm_write_reg(info, offset, val); 218 offset += 4; 219 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[6]); 220 elm_write_reg(info, offset, val); 221 offset += 4; 222 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[2]); 223 elm_write_reg(info, offset, val); 224 offset += 4; 225 val = (__force u32)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 */ 247static 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 */ 279static 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 */ 336void 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} 361EXPORT_SYMBOL(elm_decode_bch_error_page); 362 363static 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 381static 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_put_sync(&pdev->dev); 415 pm_runtime_disable(&pdev->dev); 416 dev_err(&pdev->dev, "can't enable clock\n"); 417 return ret; 418 } 419 420 init_completion(&info->elm_completion); 421 INIT_LIST_HEAD(&info->list); 422 list_add(&info->list, &elm_devices); 423 platform_set_drvdata(pdev, info); 424 return ret; 425} 426 427static int elm_remove(struct platform_device *pdev) 428{ 429 pm_runtime_put_sync(&pdev->dev); 430 pm_runtime_disable(&pdev->dev); 431 return 0; 432} 433 434#ifdef CONFIG_PM_SLEEP 435/** 436 * elm_context_save 437 * saves ELM configurations to preserve them across Hardware powered-down 438 */ 439static int elm_context_save(struct elm_info *info) 440{ 441 struct elm_registers *regs = &info->elm_regs; 442 enum bch_ecc bch_type = info->bch_type; 443 u32 offset = 0, i; 444 445 regs->elm_irqenable = elm_read_reg(info, ELM_IRQENABLE); 446 regs->elm_sysconfig = elm_read_reg(info, ELM_SYSCONFIG); 447 regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG); 448 regs->elm_page_ctrl = elm_read_reg(info, ELM_PAGE_CTRL); 449 for (i = 0; i < ERROR_VECTOR_MAX; i++) { 450 offset = i * SYNDROME_FRAGMENT_REG_SIZE; 451 switch (bch_type) { 452 case BCH16_ECC: 453 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info, 454 ELM_SYNDROME_FRAGMENT_6 + offset); 455 regs->elm_syndrome_fragment_5[i] = elm_read_reg(info, 456 ELM_SYNDROME_FRAGMENT_5 + offset); 457 regs->elm_syndrome_fragment_4[i] = elm_read_reg(info, 458 ELM_SYNDROME_FRAGMENT_4 + offset); 459 fallthrough; 460 case BCH8_ECC: 461 regs->elm_syndrome_fragment_3[i] = elm_read_reg(info, 462 ELM_SYNDROME_FRAGMENT_3 + offset); 463 regs->elm_syndrome_fragment_2[i] = elm_read_reg(info, 464 ELM_SYNDROME_FRAGMENT_2 + offset); 465 fallthrough; 466 case BCH4_ECC: 467 regs->elm_syndrome_fragment_1[i] = elm_read_reg(info, 468 ELM_SYNDROME_FRAGMENT_1 + offset); 469 regs->elm_syndrome_fragment_0[i] = elm_read_reg(info, 470 ELM_SYNDROME_FRAGMENT_0 + offset); 471 break; 472 default: 473 return -EINVAL; 474 } 475 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs 476 * to be saved for all BCH schemes*/ 477 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info, 478 ELM_SYNDROME_FRAGMENT_6 + offset); 479 } 480 return 0; 481} 482 483/** 484 * elm_context_restore 485 * writes configurations saved duing power-down back into ELM registers 486 */ 487static int elm_context_restore(struct elm_info *info) 488{ 489 struct elm_registers *regs = &info->elm_regs; 490 enum bch_ecc bch_type = info->bch_type; 491 u32 offset = 0, i; 492 493 elm_write_reg(info, ELM_IRQENABLE, regs->elm_irqenable); 494 elm_write_reg(info, ELM_SYSCONFIG, regs->elm_sysconfig); 495 elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config); 496 elm_write_reg(info, ELM_PAGE_CTRL, regs->elm_page_ctrl); 497 for (i = 0; i < ERROR_VECTOR_MAX; i++) { 498 offset = i * SYNDROME_FRAGMENT_REG_SIZE; 499 switch (bch_type) { 500 case BCH16_ECC: 501 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset, 502 regs->elm_syndrome_fragment_6[i]); 503 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset, 504 regs->elm_syndrome_fragment_5[i]); 505 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset, 506 regs->elm_syndrome_fragment_4[i]); 507 fallthrough; 508 case BCH8_ECC: 509 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset, 510 regs->elm_syndrome_fragment_3[i]); 511 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset, 512 regs->elm_syndrome_fragment_2[i]); 513 fallthrough; 514 case BCH4_ECC: 515 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset, 516 regs->elm_syndrome_fragment_1[i]); 517 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset, 518 regs->elm_syndrome_fragment_0[i]); 519 break; 520 default: 521 return -EINVAL; 522 } 523 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */ 524 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset, 525 regs->elm_syndrome_fragment_6[i] & 526 ELM_SYNDROME_VALID); 527 } 528 return 0; 529} 530 531static int elm_suspend(struct device *dev) 532{ 533 struct elm_info *info = dev_get_drvdata(dev); 534 elm_context_save(info); 535 pm_runtime_put_sync(dev); 536 return 0; 537} 538 539static int elm_resume(struct device *dev) 540{ 541 struct elm_info *info = dev_get_drvdata(dev); 542 pm_runtime_get_sync(dev); 543 elm_context_restore(info); 544 return 0; 545} 546#endif 547 548static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume); 549 550#ifdef CONFIG_OF 551static const struct of_device_id elm_of_match[] = { 552 { .compatible = "ti,am3352-elm" }, 553 {}, 554}; 555MODULE_DEVICE_TABLE(of, elm_of_match); 556#endif 557 558static struct platform_driver elm_driver = { 559 .driver = { 560 .name = DRIVER_NAME, 561 .of_match_table = of_match_ptr(elm_of_match), 562 .pm = &elm_pm_ops, 563 }, 564 .probe = elm_probe, 565 .remove = elm_remove, 566}; 567 568module_platform_driver(elm_driver); 569 570MODULE_DESCRIPTION("ELM driver for BCH error correction"); 571MODULE_AUTHOR("Texas Instruments"); 572MODULE_ALIAS("platform:" DRIVER_NAME); 573MODULE_LICENSE("GPL v2"); 574