summaryrefslogtreecommitdiffstats
path: root/drivers/mtd/devices/elm.c
blob: b4f61c7fc161c6dc32e080e8328ca78f96fa1093 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
/*
 * Error Location Module
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 */

#define DRIVER_NAME	"omap-elm"

#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/sched.h>
#include <linux/pm_runtime.h>
#include <linux/platform_data/elm.h>

#define ELM_SYSCONFIG			0x010
#define ELM_IRQSTATUS			0x018
#define ELM_IRQENABLE			0x01c
#define ELM_LOCATION_CONFIG		0x020
#define ELM_PAGE_CTRL			0x080
#define ELM_SYNDROME_FRAGMENT_0		0x400
#define ELM_SYNDROME_FRAGMENT_1		0x404
#define ELM_SYNDROME_FRAGMENT_2		0x408
#define ELM_SYNDROME_FRAGMENT_3		0x40c
#define ELM_SYNDROME_FRAGMENT_4		0x410
#define ELM_SYNDROME_FRAGMENT_5		0x414
#define ELM_SYNDROME_FRAGMENT_6		0x418
#define ELM_LOCATION_STATUS		0x800
#define ELM_ERROR_LOCATION_0		0x880

/* ELM Interrupt Status Register */
#define INTR_STATUS_PAGE_VALID		BIT(8)

/* ELM Interrupt Enable Register */
#define INTR_EN_PAGE_MASK		BIT(8)

/* ELM Location Configuration Register */
#define ECC_BCH_LEVEL_MASK		0x3

/* ELM syndrome */
#define ELM_SYNDROME_VALID		BIT(16)

/* ELM_LOCATION_STATUS Register */
#define ECC_CORRECTABLE_MASK		BIT(8)
#define ECC_NB_ERRORS_MASK		0x1f

/* ELM_ERROR_LOCATION_0-15 Registers */
#define ECC_ERROR_LOCATION_MASK		0x1fff

#define ELM_ECC_SIZE			0x7ff

#define SYNDROME_FRAGMENT_REG_SIZE	0x40
#define ERROR_LOCATION_SIZE		0x100

struct elm_registers {
	u32 elm_irqenable;
	u32 elm_sysconfig;
	u32 elm_location_config;
	u32 elm_page_ctrl;
	u32 elm_syndrome_fragment_6[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_5[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_4[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_3[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_2[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_1[ERROR_VECTOR_MAX];
	u32 elm_syndrome_fragment_0[ERROR_VECTOR_MAX];
};

struct elm_info {
	struct device *dev;
	void __iomem *elm_base;
	struct completion elm_completion;
	struct list_head list;
	enum bch_ecc bch_type;
	struct elm_registers elm_regs;
	int ecc_steps;
	int ecc_syndrome_size;
};

static LIST_HEAD(elm_devices);

static void elm_write_reg(struct elm_info *info, int offset, u32 val)
{
	writel(val, info->elm_base + offset);
}

static u32 elm_read_reg(struct elm_info *info, int offset)
{
	return readl(info->elm_base + offset);
}

/**
 * elm_config - Configure ELM module
 * @dev:	ELM device
 * @bch_type:	Type of BCH ecc
 */
int elm_config(struct device *dev, enum bch_ecc bch_type,
	int ecc_steps, int ecc_step_size, int ecc_syndrome_size)
{
	u32 reg_val;
	struct elm_info *info = dev_get_drvdata(dev);

	if (!info) {
		dev_err(dev, "Unable to configure elm - device not probed?\n");
		return -ENODEV;
	}
	/* ELM cannot detect ECC errors for chunks > 1KB */
	if (ecc_step_size > ((ELM_ECC_SIZE + 1) / 2)) {
		dev_err(dev, "unsupported config ecc-size=%d\n", ecc_step_size);
		return -EINVAL;
	}
	/* ELM support 8 error syndrome process */
	if (ecc_steps > ERROR_VECTOR_MAX) {
		dev_err(dev, "unsupported config ecc-step=%d\n", ecc_steps);
		return -EINVAL;
	}

	reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16);
	elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val);
	info->bch_type		= bch_type;
	info->ecc_steps		= ecc_steps;
	info->ecc_syndrome_size	= ecc_syndrome_size;

	return 0;
}
EXPORT_SYMBOL(elm_config);

/**
 * elm_configure_page_mode - Enable/Disable page mode
 * @info:	elm info
 * @index:	index number of syndrome fragment vector
 * @enable:	enable/disable flag for page mode
 *
 * Enable page mode for syndrome fragment index
 */
static void elm_configure_page_mode(struct elm_info *info, int index,
		bool enable)
{
	u32 reg_val;

	reg_val = elm_read_reg(info, ELM_PAGE_CTRL);
	if (enable)
		reg_val |= BIT(index);	/* enable page mode */
	else
		reg_val &= ~BIT(index);	/* disable page mode */

	elm_write_reg(info, ELM_PAGE_CTRL, reg_val);
}

/**
 * elm_load_syndrome - Load ELM syndrome reg
 * @info:	elm info
 * @err_vec:	elm error vectors
 * @ecc:	buffer with calculated ecc
 *
 * Load syndrome fragment registers with calculated ecc in reverse order.
 */
static void elm_load_syndrome(struct elm_info *info,
		struct elm_errorvec *err_vec, u8 *ecc)
{
	int i, offset;
	u32 val;

	for (i = 0; i < info->ecc_steps; i++) {

		/* Check error reported */
		if (err_vec[i].error_reported) {
			elm_configure_page_mode(info, i, true);
			offset = ELM_SYNDROME_FRAGMENT_0 +
				SYNDROME_FRAGMENT_REG_SIZE * i;
			switch (info->bch_type) {
			case BCH8_ECC:
				/* syndrome fragment 0 = ecc[9-12B] */
				val = cpu_to_be32(*(u32 *) &ecc[9]);
				elm_write_reg(info, offset, val);

				/* syndrome fragment 1 = ecc[5-8B] */
				offset += 4;
				val = cpu_to_be32(*(u32 *) &ecc[5]);
				elm_write_reg(info, offset, val);

				/* syndrome fragment 2 = ecc[1-4B] */
				offset += 4;
				val = cpu_to_be32(*(u32 *) &ecc[1]);
				elm_write_reg(info, offset, val);

				/* syndrome fragment 3 = ecc[0B] */
				offset += 4;
				val = ecc[0];
				elm_write_reg(info, offset, val);
				break;
			case BCH4_ECC:
				/* syndrome fragment 0 = ecc[20-52b] bits */
				val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) |
					((ecc[2] & 0xf) << 28);
				elm_write_reg(info, offset, val);

				/* syndrome fragment 1 = ecc[0-20b] bits */
				offset += 4;
				val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12;
				elm_write_reg(info, offset, val);
				break;
			case BCH16_ECC:
				val = cpu_to_be32(*(u32 *) &ecc[22]);
				elm_write_reg(info, offset, val);
				offset += 4;
				val = cpu_to_be32(*(u32 *) &ecc[18]);
				elm_write_reg(info, offset, val);
				offset += 4;
				val = cpu_to_be32(*(u32 *) &ecc[14]);
				elm_write_reg(info, offset, val);
				offset += 4;
				val = cpu_to_be32(*(u32 *) &ecc[10]);
				elm_write_reg(info, offset, val);
				offset += 4;
				val = cpu_to_be32(*(u32 *) &ecc[6]);
				elm_write_reg(info, offset, val);
				offset += 4;
				val = cpu_to_be32(*(u32 *) &ecc[2]);
				elm_write_reg(info, offset, val);
				offset += 4;
				val = cpu_to_be32(*(u32 *) &ecc[0]) >> 16;
				elm_write_reg(info, offset, val);
				break;
			default:
				pr_err("invalid config bch_type\n");
			}
		}

		/* Update ecc pointer with ecc byte size */
		ecc += info->ecc_syndrome_size;
	}
}

/**
 * elm_start_processing - start elm syndrome processing
 * @info:	elm info
 * @err_vec:	elm error vectors
 *
 * Set syndrome valid bit for syndrome fragment registers for which
 * elm syndrome fragment registers are loaded. This enables elm module
 * to start processing syndrome vectors.
 */
static void elm_start_processing(struct elm_info *info,
		struct elm_errorvec *err_vec)
{
	int i, offset;
	u32 reg_val;

	/*
	 * Set syndrome vector valid, so that ELM module
	 * will process it for vectors error is reported
	 */
	for (i = 0; i < info->ecc_steps; i++) {
		if (err_vec[i].error_reported) {
			offset = ELM_SYNDROME_FRAGMENT_6 +
				SYNDROME_FRAGMENT_REG_SIZE * i;
			reg_val = elm_read_reg(info, offset);
			reg_val |= ELM_SYNDROME_VALID;
			elm_write_reg(info, offset, reg_val);
		}
	}
}

/**
 * elm_error_correction - locate correctable error position
 * @info:	elm info
 * @err_vec:	elm error vectors
 *
 * On completion of processing by elm module, error location status
 * register updated with correctable/uncorrectable error information.
 * In case of correctable errors, number of errors located from
 * elm location status register & read the positions from
 * elm error location register.
 */
static void elm_error_correction(struct elm_info *info,
		struct elm_errorvec *err_vec)
{
	int i, j, errors = 0;
	int offset;
	u32 reg_val;

	for (i = 0; i < info->ecc_steps; i++) {

		/* Check error reported */
		if (err_vec[i].error_reported) {
			offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i;
			reg_val = elm_read_reg(info, offset);

			/* Check correctable error or not */
			if (reg_val & ECC_CORRECTABLE_MASK) {
				offset = ELM_ERROR_LOCATION_0 +
					ERROR_LOCATION_SIZE * i;

				/* Read count of correctable errors */
				err_vec[i].error_count = reg_val &
					ECC_NB_ERRORS_MASK;

				/* Update the error locations in error vector */
				for (j = 0; j < err_vec[i].error_count; j++) {

					reg_val = elm_read_reg(info, offset);
					err_vec[i].error_loc[j] = reg_val &
						ECC_ERROR_LOCATION_MASK;

					/* Update error location register */
					offset += 4;
				}

				errors += err_vec[i].error_count;
			} else {
				err_vec[i].error_uncorrectable = true;
			}

			/* Clearing interrupts for processed error vectors */
			elm_write_reg(info, ELM_IRQSTATUS, BIT(i));

			/* Disable page mode */
			elm_configure_page_mode(info, i, false);
		}
	}
}

/**
 * elm_decode_bch_error_page - Locate error position
 * @dev:	device pointer
 * @ecc_calc:	calculated ECC bytes from GPMC
 * @err_vec:	elm error vectors
 *
 * Called with one or more error reported vectors & vectors with
 * error reported is updated in err_vec[].error_reported
 */
void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
		struct elm_errorvec *err_vec)
{
	struct elm_info *info = dev_get_drvdata(dev);
	u32 reg_val;

	/* Enable page mode interrupt */
	reg_val = elm_read_reg(info, ELM_IRQSTATUS);
	elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID);
	elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK);

	/* Load valid ecc byte to syndrome fragment register */
	elm_load_syndrome(info, err_vec, ecc_calc);

	/* Enable syndrome processing for which syndrome fragment is updated */
	elm_start_processing(info, err_vec);

	/* Wait for ELM module to finish locating error correction */
	wait_for_completion(&info->elm_completion);

	/* Disable page mode interrupt */
	reg_val = elm_read_reg(info, ELM_IRQENABLE);
	elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK);
	elm_error_correction(info, err_vec);
}
EXPORT_SYMBOL(elm_decode_bch_error_page);

static irqreturn_t elm_isr(int this_irq, void *dev_id)
{
	u32 reg_val;
	struct elm_info *info = dev_id;

	reg_val = elm_read_reg(info, ELM_IRQSTATUS);

	/* All error vectors processed */
	if (reg_val & INTR_STATUS_PAGE_VALID) {
		elm_write_reg(info, ELM_IRQSTATUS,
				reg_val & INTR_STATUS_PAGE_VALID);
		complete(&info->elm_completion);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int elm_probe(struct platform_device *pdev)
{
	int ret = 0;
	struct resource *res, *irq;
	struct elm_info *info;

	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	info->dev = &pdev->dev;

	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!irq) {
		dev_err(&pdev->dev, "no irq resource defined\n");
		return -ENODEV;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	info->elm_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(info->elm_base))
		return PTR_ERR(info->elm_base);

	ret = devm_request_irq(&pdev->dev, irq->start, elm_isr, 0,
			pdev->name, info);
	if (ret) {
		dev_err(&pdev->dev, "failure requesting irq %i\n", irq->start);
		return ret;
	}

	pm_runtime_enable(&pdev->dev);
	if (pm_runtime_get_sync(&pdev->dev) < 0) {
		ret = -EINVAL;
		pm_runtime_disable(&pdev->dev);
		dev_err(&pdev->dev, "can't enable clock\n");
		return ret;
	}

	init_completion(&info->elm_completion);
	INIT_LIST_HEAD(&info->list);
	list_add(&info->list, &elm_devices);
	platform_set_drvdata(pdev, info);
	return ret;
}

static int elm_remove(struct platform_device *pdev)
{
	pm_runtime_put_sync(&pdev->dev);
	pm_runtime_disable(&pdev->dev);
	return 0;
}

#ifdef CONFIG_PM_SLEEP
/**
 * elm_context_save
 * saves ELM configurations to preserve them across Hardware powered-down
 */
static int elm_context_save(struct elm_info *info)
{
	struct elm_registers *regs = &info->elm_regs;
	enum bch_ecc bch_type = info->bch_type;
	u32 offset = 0, i;

	regs->elm_irqenable       = elm_read_reg(info, ELM_IRQENABLE);
	regs->elm_sysconfig       = elm_read_reg(info, ELM_SYSCONFIG);
	regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
	regs->elm_page_ctrl       = elm_read_reg(info, ELM_PAGE_CTRL);
	for (i = 0; i < ERROR_VECTOR_MAX; i++) {
		offset = i * SYNDROME_FRAGMENT_REG_SIZE;
		switch (bch_type) {
		case BCH16_ECC:
			regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_6 + offset);
			regs->elm_syndrome_fragment_5[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_5 + offset);
			regs->elm_syndrome_fragment_4[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_4 + offset);
		case BCH8_ECC:
			regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_3 + offset);
			regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_2 + offset);
		case BCH4_ECC:
			regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_1 + offset);
			regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_0 + offset);
			break;
		default:
			return -EINVAL;
		}
		/* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
		 * to be saved for all BCH schemes*/
		regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
					ELM_SYNDROME_FRAGMENT_6 + offset);
	}
	return 0;
}

/**
 * elm_context_restore
 * writes configurations saved duing power-down back into ELM registers
 */
static int elm_context_restore(struct elm_info *info)
{
	struct elm_registers *regs = &info->elm_regs;
	enum bch_ecc bch_type = info->bch_type;
	u32 offset = 0, i;

	elm_write_reg(info, ELM_IRQENABLE,	 regs->elm_irqenable);
	elm_write_reg(info, ELM_SYSCONFIG,	 regs->elm_sysconfig);
	elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
	elm_write_reg(info, ELM_PAGE_CTRL,	 regs->elm_page_ctrl);
	for (i = 0; i < ERROR_VECTOR_MAX; i++) {
		offset = i * SYNDROME_FRAGMENT_REG_SIZE;
		switch (bch_type) {
		case BCH16_ECC:
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
					regs->elm_syndrome_fragment_6[i]);
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset,
					regs->elm_syndrome_fragment_5[i]);
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
					regs->elm_syndrome_fragment_4[i]);
		case BCH8_ECC:
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
					regs->elm_syndrome_fragment_3[i]);
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
					regs->elm_syndrome_fragment_2[i]);
		case BCH4_ECC:
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
					regs->elm_syndrome_fragment_1[i]);
			elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
					regs->elm_syndrome_fragment_0[i]);
			break;
		default:
			return -EINVAL;
		}
		/* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
		elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
					regs->elm_syndrome_fragment_6[i] &
							 ELM_SYNDROME_VALID);
	}
	return 0;
}

static int elm_suspend(struct device *dev)
{
	struct elm_info *info = dev_get_drvdata(dev);
	elm_context_save(info);
	pm_runtime_put_sync(dev);
	return 0;
}

static int elm_resume(struct device *dev)
{
	struct elm_info *info = dev_get_drvdata(dev);
	pm_runtime_get_sync(dev);
	elm_context_restore(info);
	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);

#ifdef CONFIG_OF
static const struct of_device_id elm_of_match[] = {
	{ .compatible = "ti,am3352-elm" },
	{},
};
MODULE_DEVICE_TABLE(of, elm_of_match);
#endif

static struct platform_driver elm_driver = {
	.driver	= {
		.name	= DRIVER_NAME,
		.owner	= THIS_MODULE,
		.of_match_table = of_match_ptr(elm_of_match),
		.pm	= &elm_pm_ops,
	},
	.probe	= elm_probe,
	.remove	= elm_remove,
};

module_platform_driver(elm_driver);

MODULE_DESCRIPTION("ELM driver for BCH error correction");
MODULE_AUTHOR("Texas Instruments");
MODULE_ALIAS("platform: elm");
MODULE_LICENSE("GPL v2");
OpenPOWER on IntegriCloud