Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

Linux/drivers/mtd/devices/elm.c

  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 -ENODEV;
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 irq %i\n", irq->start);
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                 case BCH8_ECC:
469                         regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
470                                         ELM_SYNDROME_FRAGMENT_3 + offset);
471                         regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
472                                         ELM_SYNDROME_FRAGMENT_2 + offset);
473                 case BCH4_ECC:
474                         regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
475                                         ELM_SYNDROME_FRAGMENT_1 + offset);
476                         regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
477                                         ELM_SYNDROME_FRAGMENT_0 + offset);
478                         break;
479                 default:
480                         return -EINVAL;
481                 }
482                 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
483                  * to be saved for all BCH schemes*/
484                 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
485                                         ELM_SYNDROME_FRAGMENT_6 + offset);
486         }
487         return 0;
488 }
489 
490 /**
491  * elm_context_restore
492  * writes configurations saved duing power-down back into ELM registers
493  */
494 static int elm_context_restore(struct elm_info *info)
495 {
496         struct elm_registers *regs = &info->elm_regs;
497         enum bch_ecc bch_type = info->bch_type;
498         u32 offset = 0, i;
499 
500         elm_write_reg(info, ELM_IRQENABLE,       regs->elm_irqenable);
501         elm_write_reg(info, ELM_SYSCONFIG,       regs->elm_sysconfig);
502         elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
503         elm_write_reg(info, ELM_PAGE_CTRL,       regs->elm_page_ctrl);
504         for (i = 0; i < ERROR_VECTOR_MAX; i++) {
505                 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
506                 switch (bch_type) {
507                 case BCH16_ECC:
508                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
509                                         regs->elm_syndrome_fragment_6[i]);
510                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset,
511                                         regs->elm_syndrome_fragment_5[i]);
512                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
513                                         regs->elm_syndrome_fragment_4[i]);
514                 case BCH8_ECC:
515                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
516                                         regs->elm_syndrome_fragment_3[i]);
517                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
518                                         regs->elm_syndrome_fragment_2[i]);
519                 case BCH4_ECC:
520                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
521                                         regs->elm_syndrome_fragment_1[i]);
522                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
523                                         regs->elm_syndrome_fragment_0[i]);
524                         break;
525                 default:
526                         return -EINVAL;
527                 }
528                 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
529                 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
530                                         regs->elm_syndrome_fragment_6[i] &
531                                                          ELM_SYNDROME_VALID);
532         }
533         return 0;
534 }
535 
536 static int elm_suspend(struct device *dev)
537 {
538         struct elm_info *info = dev_get_drvdata(dev);
539         elm_context_save(info);
540         pm_runtime_put_sync(dev);
541         return 0;
542 }
543 
544 static int elm_resume(struct device *dev)
545 {
546         struct elm_info *info = dev_get_drvdata(dev);
547         pm_runtime_get_sync(dev);
548         elm_context_restore(info);
549         return 0;
550 }
551 #endif
552 
553 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
554 
555 #ifdef CONFIG_OF
556 static const struct of_device_id elm_of_match[] = {
557         { .compatible = "ti,am3352-elm" },
558         {},
559 };
560 MODULE_DEVICE_TABLE(of, elm_of_match);
561 #endif
562 
563 static struct platform_driver elm_driver = {
564         .driver = {
565                 .name   = DRIVER_NAME,
566                 .owner  = THIS_MODULE,
567                 .of_match_table = of_match_ptr(elm_of_match),
568                 .pm     = &elm_pm_ops,
569         },
570         .probe  = elm_probe,
571         .remove = elm_remove,
572 };
573 
574 module_platform_driver(elm_driver);
575 
576 MODULE_DESCRIPTION("ELM driver for BCH error correction");
577 MODULE_AUTHOR("Texas Instruments");
578 MODULE_ALIAS("platform: elm");
579 MODULE_LICENSE("GPL v2");
580 

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