treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.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 - http://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  */
100 int 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 }
129 EXPORT_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  */
139 static 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  */
161 static 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 = 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 = 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 = 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 = (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 = cpu_to_be32(*(u32 *) &ecc[0]) >> 12;
204                                 elm_write_reg(info, offset, val);
205                                 break;
206                         case BCH16_ECC:
207                                 val = cpu_to_be32(*(u32 *) &ecc[22]);
208                                 elm_write_reg(info, offset, val);
209                                 offset += 4;
210                                 val = cpu_to_be32(*(u32 *) &ecc[18]);
211                                 elm_write_reg(info, offset, val);
212                                 offset += 4;
213                                 val = cpu_to_be32(*(u32 *) &ecc[14]);
214                                 elm_write_reg(info, offset, val);
215                                 offset += 4;
216                                 val = cpu_to_be32(*(u32 *) &ecc[10]);
217                                 elm_write_reg(info, offset, val);
218                                 offset += 4;
219                                 val = cpu_to_be32(*(u32 *) &ecc[6]);
220                                 elm_write_reg(info, offset, val);
221                                 offset += 4;
222                                 val = cpu_to_be32(*(u32 *) &ecc[2]);
223                                 elm_write_reg(info, offset, val);
224                                 offset += 4;
225                                 val = 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  */
247 static 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  */
279 static 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  */
336 void 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 }
361 EXPORT_SYMBOL(elm_decode_bch_error_page);
362
363 static 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
381 static 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_disable(&pdev->dev);
415                 dev_err(&pdev->dev, "can't enable clock\n");
416                 return ret;
417         }
418
419         init_completion(&info->elm_completion);
420         INIT_LIST_HEAD(&info->list);
421         list_add(&info->list, &elm_devices);
422         platform_set_drvdata(pdev, info);
423         return ret;
424 }
425
426 static int elm_remove(struct platform_device *pdev)
427 {
428         pm_runtime_put_sync(&pdev->dev);
429         pm_runtime_disable(&pdev->dev);
430         return 0;
431 }
432
433 #ifdef CONFIG_PM_SLEEP
434 /**
435  * elm_context_save
436  * saves ELM configurations to preserve them across Hardware powered-down
437  */
438 static int elm_context_save(struct elm_info *info)
439 {
440         struct elm_registers *regs = &info->elm_regs;
441         enum bch_ecc bch_type = info->bch_type;
442         u32 offset = 0, i;
443
444         regs->elm_irqenable       = elm_read_reg(info, ELM_IRQENABLE);
445         regs->elm_sysconfig       = elm_read_reg(info, ELM_SYSCONFIG);
446         regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
447         regs->elm_page_ctrl       = elm_read_reg(info, ELM_PAGE_CTRL);
448         for (i = 0; i < ERROR_VECTOR_MAX; i++) {
449                 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
450                 switch (bch_type) {
451                 case BCH16_ECC:
452                         regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
453                                         ELM_SYNDROME_FRAGMENT_6 + offset);
454                         regs->elm_syndrome_fragment_5[i] = elm_read_reg(info,
455                                         ELM_SYNDROME_FRAGMENT_5 + offset);
456                         regs->elm_syndrome_fragment_4[i] = elm_read_reg(info,
457                                         ELM_SYNDROME_FRAGMENT_4 + offset);
458                         /* fall through */
459                 case BCH8_ECC:
460                         regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
461                                         ELM_SYNDROME_FRAGMENT_3 + offset);
462                         regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
463                                         ELM_SYNDROME_FRAGMENT_2 + offset);
464                         /* fall through */
465                 case BCH4_ECC:
466                         regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
467                                         ELM_SYNDROME_FRAGMENT_1 + offset);
468                         regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
469                                         ELM_SYNDROME_FRAGMENT_0 + offset);
470                         break;
471                 default:
472                         return -EINVAL;
473                 }
474                 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
475                  * to be saved for all BCH schemes*/
476                 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
477                                         ELM_SYNDROME_FRAGMENT_6 + offset);
478         }
479         return 0;
480 }
481
482 /**
483  * elm_context_restore
484  * writes configurations saved duing power-down back into ELM registers
485  */
486 static int elm_context_restore(struct elm_info *info)
487 {
488         struct elm_registers *regs = &info->elm_regs;
489         enum bch_ecc bch_type = info->bch_type;
490         u32 offset = 0, i;
491
492         elm_write_reg(info, ELM_IRQENABLE,       regs->elm_irqenable);
493         elm_write_reg(info, ELM_SYSCONFIG,       regs->elm_sysconfig);
494         elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
495         elm_write_reg(info, ELM_PAGE_CTRL,       regs->elm_page_ctrl);
496         for (i = 0; i < ERROR_VECTOR_MAX; i++) {
497                 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
498                 switch (bch_type) {
499                 case BCH16_ECC:
500                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
501                                         regs->elm_syndrome_fragment_6[i]);
502                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset,
503                                         regs->elm_syndrome_fragment_5[i]);
504                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
505                                         regs->elm_syndrome_fragment_4[i]);
506                         /* fall through */
507                 case BCH8_ECC:
508                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
509                                         regs->elm_syndrome_fragment_3[i]);
510                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
511                                         regs->elm_syndrome_fragment_2[i]);
512                         /* fall through */
513                 case BCH4_ECC:
514                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
515                                         regs->elm_syndrome_fragment_1[i]);
516                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
517                                         regs->elm_syndrome_fragment_0[i]);
518                         break;
519                 default:
520                         return -EINVAL;
521                 }
522                 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
523                 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
524                                         regs->elm_syndrome_fragment_6[i] &
525                                                          ELM_SYNDROME_VALID);
526         }
527         return 0;
528 }
529
530 static int elm_suspend(struct device *dev)
531 {
532         struct elm_info *info = dev_get_drvdata(dev);
533         elm_context_save(info);
534         pm_runtime_put_sync(dev);
535         return 0;
536 }
537
538 static int elm_resume(struct device *dev)
539 {
540         struct elm_info *info = dev_get_drvdata(dev);
541         pm_runtime_get_sync(dev);
542         elm_context_restore(info);
543         return 0;
544 }
545 #endif
546
547 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
548
549 #ifdef CONFIG_OF
550 static const struct of_device_id elm_of_match[] = {
551         { .compatible = "ti,am3352-elm" },
552         {},
553 };
554 MODULE_DEVICE_TABLE(of, elm_of_match);
555 #endif
556
557 static struct platform_driver elm_driver = {
558         .driver = {
559                 .name   = DRIVER_NAME,
560                 .of_match_table = of_match_ptr(elm_of_match),
561                 .pm     = &elm_pm_ops,
562         },
563         .probe  = elm_probe,
564         .remove = elm_remove,
565 };
566
567 module_platform_driver(elm_driver);
568
569 MODULE_DESCRIPTION("ELM driver for BCH error correction");
570 MODULE_AUTHOR("Texas Instruments");
571 MODULE_ALIAS("platform:" DRIVER_NAME);
572 MODULE_LICENSE("GPL v2");