Merge tag 'for-linus' of git://github.com/openrisc/linux
[linux-2.6-microblaze.git] / drivers / mtd / nand / raw / omap_elm.c
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) {
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, errors = 0;
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
316                                 errors += err_vec[i].error_count;
317                         } else {
318                                 err_vec[i].error_uncorrectable = true;
319                         }
320
321                         /* Clearing interrupts for processed error vectors */
322                         elm_write_reg(info, ELM_IRQSTATUS, BIT(i));
323
324                         /* Disable page mode */
325                         elm_configure_page_mode(info, i, false);
326                 }
327         }
328 }
329
330 /**
331  * elm_decode_bch_error_page - Locate error position
332  * @dev:        device pointer
333  * @ecc_calc:   calculated ECC bytes from GPMC
334  * @err_vec:    elm error vectors
335  *
336  * Called with one or more error reported vectors & vectors with
337  * error reported is updated in err_vec[].error_reported
338  */
339 void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
340                 struct elm_errorvec *err_vec)
341 {
342         struct elm_info *info = dev_get_drvdata(dev);
343         u32 reg_val;
344
345         /* Enable page mode interrupt */
346         reg_val = elm_read_reg(info, ELM_IRQSTATUS);
347         elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID);
348         elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK);
349
350         /* Load valid ecc byte to syndrome fragment register */
351         elm_load_syndrome(info, err_vec, ecc_calc);
352
353         /* Enable syndrome processing for which syndrome fragment is updated */
354         elm_start_processing(info, err_vec);
355
356         /* Wait for ELM module to finish locating error correction */
357         wait_for_completion(&info->elm_completion);
358
359         /* Disable page mode interrupt */
360         reg_val = elm_read_reg(info, ELM_IRQENABLE);
361         elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK);
362         elm_error_correction(info, err_vec);
363 }
364 EXPORT_SYMBOL(elm_decode_bch_error_page);
365
366 static irqreturn_t elm_isr(int this_irq, void *dev_id)
367 {
368         u32 reg_val;
369         struct elm_info *info = dev_id;
370
371         reg_val = elm_read_reg(info, ELM_IRQSTATUS);
372
373         /* All error vectors processed */
374         if (reg_val & INTR_STATUS_PAGE_VALID) {
375                 elm_write_reg(info, ELM_IRQSTATUS,
376                                 reg_val & INTR_STATUS_PAGE_VALID);
377                 complete(&info->elm_completion);
378                 return IRQ_HANDLED;
379         }
380
381         return IRQ_NONE;
382 }
383
384 static int elm_probe(struct platform_device *pdev)
385 {
386         int ret = 0;
387         struct resource *res, *irq;
388         struct elm_info *info;
389
390         info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
391         if (!info)
392                 return -ENOMEM;
393
394         info->dev = &pdev->dev;
395
396         irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
397         if (!irq) {
398                 dev_err(&pdev->dev, "no irq resource defined\n");
399                 return -ENODEV;
400         }
401
402         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
403         info->elm_base = devm_ioremap_resource(&pdev->dev, res);
404         if (IS_ERR(info->elm_base))
405                 return PTR_ERR(info->elm_base);
406
407         ret = devm_request_irq(&pdev->dev, irq->start, elm_isr, 0,
408                         pdev->name, info);
409         if (ret) {
410                 dev_err(&pdev->dev, "failure requesting %pr\n", irq);
411                 return ret;
412         }
413
414         pm_runtime_enable(&pdev->dev);
415         if (pm_runtime_get_sync(&pdev->dev) < 0) {
416                 ret = -EINVAL;
417                 pm_runtime_put_sync(&pdev->dev);
418                 pm_runtime_disable(&pdev->dev);
419                 dev_err(&pdev->dev, "can't enable clock\n");
420                 return ret;
421         }
422
423         init_completion(&info->elm_completion);
424         INIT_LIST_HEAD(&info->list);
425         list_add(&info->list, &elm_devices);
426         platform_set_drvdata(pdev, info);
427         return ret;
428 }
429
430 static int elm_remove(struct platform_device *pdev)
431 {
432         pm_runtime_put_sync(&pdev->dev);
433         pm_runtime_disable(&pdev->dev);
434         return 0;
435 }
436
437 #ifdef CONFIG_PM_SLEEP
438 /*
439  * elm_context_save
440  * saves ELM configurations to preserve them across Hardware powered-down
441  */
442 static int elm_context_save(struct elm_info *info)
443 {
444         struct elm_registers *regs = &info->elm_regs;
445         enum bch_ecc bch_type = info->bch_type;
446         u32 offset = 0, i;
447
448         regs->elm_irqenable       = elm_read_reg(info, ELM_IRQENABLE);
449         regs->elm_sysconfig       = elm_read_reg(info, ELM_SYSCONFIG);
450         regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
451         regs->elm_page_ctrl       = elm_read_reg(info, ELM_PAGE_CTRL);
452         for (i = 0; i < ERROR_VECTOR_MAX; i++) {
453                 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
454                 switch (bch_type) {
455                 case BCH16_ECC:
456                         regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
457                                         ELM_SYNDROME_FRAGMENT_6 + offset);
458                         regs->elm_syndrome_fragment_5[i] = elm_read_reg(info,
459                                         ELM_SYNDROME_FRAGMENT_5 + offset);
460                         regs->elm_syndrome_fragment_4[i] = elm_read_reg(info,
461                                         ELM_SYNDROME_FRAGMENT_4 + offset);
462                         fallthrough;
463                 case BCH8_ECC:
464                         regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
465                                         ELM_SYNDROME_FRAGMENT_3 + offset);
466                         regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
467                                         ELM_SYNDROME_FRAGMENT_2 + offset);
468                         fallthrough;
469                 case BCH4_ECC:
470                         regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
471                                         ELM_SYNDROME_FRAGMENT_1 + offset);
472                         regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
473                                         ELM_SYNDROME_FRAGMENT_0 + offset);
474                         break;
475                 default:
476                         return -EINVAL;
477                 }
478                 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
479                  * to be saved for all BCH schemes*/
480                 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
481                                         ELM_SYNDROME_FRAGMENT_6 + offset);
482         }
483         return 0;
484 }
485
486 /*
487  * elm_context_restore
488  * writes configurations saved duing power-down back into ELM registers
489  */
490 static int elm_context_restore(struct elm_info *info)
491 {
492         struct elm_registers *regs = &info->elm_regs;
493         enum bch_ecc bch_type = info->bch_type;
494         u32 offset = 0, i;
495
496         elm_write_reg(info, ELM_IRQENABLE,       regs->elm_irqenable);
497         elm_write_reg(info, ELM_SYSCONFIG,       regs->elm_sysconfig);
498         elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
499         elm_write_reg(info, ELM_PAGE_CTRL,       regs->elm_page_ctrl);
500         for (i = 0; i < ERROR_VECTOR_MAX; i++) {
501                 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
502                 switch (bch_type) {
503                 case BCH16_ECC:
504                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
505                                         regs->elm_syndrome_fragment_6[i]);
506                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset,
507                                         regs->elm_syndrome_fragment_5[i]);
508                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
509                                         regs->elm_syndrome_fragment_4[i]);
510                         fallthrough;
511                 case BCH8_ECC:
512                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
513                                         regs->elm_syndrome_fragment_3[i]);
514                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
515                                         regs->elm_syndrome_fragment_2[i]);
516                         fallthrough;
517                 case BCH4_ECC:
518                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
519                                         regs->elm_syndrome_fragment_1[i]);
520                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
521                                         regs->elm_syndrome_fragment_0[i]);
522                         break;
523                 default:
524                         return -EINVAL;
525                 }
526                 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
527                 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
528                                         regs->elm_syndrome_fragment_6[i] &
529                                                          ELM_SYNDROME_VALID);
530         }
531         return 0;
532 }
533
534 static int elm_suspend(struct device *dev)
535 {
536         struct elm_info *info = dev_get_drvdata(dev);
537         elm_context_save(info);
538         pm_runtime_put_sync(dev);
539         return 0;
540 }
541
542 static int elm_resume(struct device *dev)
543 {
544         struct elm_info *info = dev_get_drvdata(dev);
545         pm_runtime_get_sync(dev);
546         elm_context_restore(info);
547         return 0;
548 }
549 #endif
550
551 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
552
553 #ifdef CONFIG_OF
554 static const struct of_device_id elm_of_match[] = {
555         { .compatible = "ti,am3352-elm" },
556         {},
557 };
558 MODULE_DEVICE_TABLE(of, elm_of_match);
559 #endif
560
561 static struct platform_driver elm_driver = {
562         .driver = {
563                 .name   = DRIVER_NAME,
564                 .of_match_table = of_match_ptr(elm_of_match),
565                 .pm     = &elm_pm_ops,
566         },
567         .probe  = elm_probe,
568         .remove = elm_remove,
569 };
570
571 module_platform_driver(elm_driver);
572
573 MODULE_DESCRIPTION("ELM driver for BCH error correction");
574 MODULE_AUTHOR("Texas Instruments");
575 MODULE_ALIAS("platform:" DRIVER_NAME);
576 MODULE_LICENSE("GPL v2");