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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 * @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 */
103int 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 && 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}
132EXPORT_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 */
142static 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 */
164static 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 = (__force u32)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 = (__force u32)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 = (__force u32)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 = ((__force u32)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 = (__force u32)cpu_to_be32(*(u32 *)&ecc[0]) >> 12;
207 elm_write_reg(info, offset, val);
208 break;
209 case BCH16_ECC:
210 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[22]);
211 elm_write_reg(info, offset, val);
212 offset += 4;
213 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[18]);
214 elm_write_reg(info, offset, val);
215 offset += 4;
216 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[14]);
217 elm_write_reg(info, offset, val);
218 offset += 4;
219 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[10]);
220 elm_write_reg(info, offset, val);
221 offset += 4;
222 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[6]);
223 elm_write_reg(info, offset, val);
224 offset += 4;
225 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[2]);
226 elm_write_reg(info, offset, val);
227 offset += 4;
228 val = (__force u32)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 */
250static 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 */
282static void elm_error_correction(struct elm_info *info,
283 struct elm_errorvec *err_vec)
284{
285 int i, j;
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 } else {
316 err_vec[i].error_uncorrectable = true;
317 }
318
319 /* Clearing interrupts for processed error vectors */
320 elm_write_reg(info, ELM_IRQSTATUS, BIT(i));
321
322 /* Disable page mode */
323 elm_configure_page_mode(info, i, false);
324 }
325 }
326}
327
328/**
329 * elm_decode_bch_error_page - Locate error position
330 * @dev: device pointer
331 * @ecc_calc: calculated ECC bytes from GPMC
332 * @err_vec: elm error vectors
333 *
334 * Called with one or more error reported vectors & vectors with
335 * error reported is updated in err_vec[].error_reported
336 */
337void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
338 struct elm_errorvec *err_vec)
339{
340 struct elm_info *info = dev_get_drvdata(dev);
341 u32 reg_val;
342
343 /* Enable page mode interrupt */
344 reg_val = elm_read_reg(info, ELM_IRQSTATUS);
345 elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID);
346 elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK);
347
348 /* Load valid ecc byte to syndrome fragment register */
349 elm_load_syndrome(info, err_vec, ecc_calc);
350
351 /* Enable syndrome processing for which syndrome fragment is updated */
352 elm_start_processing(info, err_vec);
353
354 /* Wait for ELM module to finish locating error correction */
355 wait_for_completion(&info->elm_completion);
356
357 /* Disable page mode interrupt */
358 reg_val = elm_read_reg(info, ELM_IRQENABLE);
359 elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK);
360 elm_error_correction(info, err_vec);
361}
362EXPORT_SYMBOL(elm_decode_bch_error_page);
363
364static irqreturn_t elm_isr(int this_irq, void *dev_id)
365{
366 u32 reg_val;
367 struct elm_info *info = dev_id;
368
369 reg_val = elm_read_reg(info, ELM_IRQSTATUS);
370
371 /* All error vectors processed */
372 if (reg_val & INTR_STATUS_PAGE_VALID) {
373 elm_write_reg(info, ELM_IRQSTATUS,
374 reg_val & INTR_STATUS_PAGE_VALID);
375 complete(&info->elm_completion);
376 return IRQ_HANDLED;
377 }
378
379 return IRQ_NONE;
380}
381
382static int elm_probe(struct platform_device *pdev)
383{
384 int ret = 0;
385 struct elm_info *info;
386 int irq;
387
388 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
389 if (!info)
390 return -ENOMEM;
391
392 info->dev = &pdev->dev;
393
394 irq = platform_get_irq(pdev, 0);
395 if (irq < 0)
396 return irq;
397
398 info->elm_base = devm_platform_ioremap_resource(pdev, 0);
399 if (IS_ERR(info->elm_base))
400 return PTR_ERR(info->elm_base);
401
402 ret = devm_request_irq(&pdev->dev, irq, elm_isr, 0,
403 pdev->name, info);
404 if (ret) {
405 dev_err(&pdev->dev, "failure requesting %d\n", irq);
406 return ret;
407 }
408
409 pm_runtime_enable(&pdev->dev);
410 if (pm_runtime_get_sync(&pdev->dev) < 0) {
411 ret = -EINVAL;
412 pm_runtime_put_sync(&pdev->dev);
413 pm_runtime_disable(&pdev->dev);
414 dev_err(&pdev->dev, "can't enable clock\n");
415 return ret;
416 }
417
418 init_completion(&info->elm_completion);
419 INIT_LIST_HEAD(&info->list);
420 list_add(&info->list, &elm_devices);
421 platform_set_drvdata(pdev, info);
422 return ret;
423}
424
425static void elm_remove(struct platform_device *pdev)
426{
427 pm_runtime_put_sync(&pdev->dev);
428 pm_runtime_disable(&pdev->dev);
429}
430
431#ifdef CONFIG_PM_SLEEP
432/*
433 * elm_context_save
434 * saves ELM configurations to preserve them across Hardware powered-down
435 */
436static int elm_context_save(struct elm_info *info)
437{
438 struct elm_registers *regs = &info->elm_regs;
439 enum bch_ecc bch_type = info->bch_type;
440 u32 offset = 0, i;
441
442 regs->elm_irqenable = elm_read_reg(info, ELM_IRQENABLE);
443 regs->elm_sysconfig = elm_read_reg(info, ELM_SYSCONFIG);
444 regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
445 regs->elm_page_ctrl = elm_read_reg(info, ELM_PAGE_CTRL);
446 for (i = 0; i < ERROR_VECTOR_MAX; i++) {
447 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
448 switch (bch_type) {
449 case BCH16_ECC:
450 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
451 ELM_SYNDROME_FRAGMENT_6 + offset);
452 regs->elm_syndrome_fragment_5[i] = elm_read_reg(info,
453 ELM_SYNDROME_FRAGMENT_5 + offset);
454 regs->elm_syndrome_fragment_4[i] = elm_read_reg(info,
455 ELM_SYNDROME_FRAGMENT_4 + offset);
456 fallthrough;
457 case BCH8_ECC:
458 regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
459 ELM_SYNDROME_FRAGMENT_3 + offset);
460 regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
461 ELM_SYNDROME_FRAGMENT_2 + offset);
462 fallthrough;
463 case BCH4_ECC:
464 regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
465 ELM_SYNDROME_FRAGMENT_1 + offset);
466 regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
467 ELM_SYNDROME_FRAGMENT_0 + offset);
468 break;
469 default:
470 return -EINVAL;
471 }
472 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
473 * to be saved for all BCH schemes*/
474 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
475 ELM_SYNDROME_FRAGMENT_6 + offset);
476 }
477 return 0;
478}
479
480/*
481 * elm_context_restore
482 * writes configurations saved duing power-down back into ELM registers
483 */
484static int elm_context_restore(struct elm_info *info)
485{
486 struct elm_registers *regs = &info->elm_regs;
487 enum bch_ecc bch_type = info->bch_type;
488 u32 offset = 0, i;
489
490 elm_write_reg(info, ELM_IRQENABLE, regs->elm_irqenable);
491 elm_write_reg(info, ELM_SYSCONFIG, regs->elm_sysconfig);
492 elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
493 elm_write_reg(info, ELM_PAGE_CTRL, regs->elm_page_ctrl);
494 for (i = 0; i < ERROR_VECTOR_MAX; i++) {
495 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
496 switch (bch_type) {
497 case BCH16_ECC:
498 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
499 regs->elm_syndrome_fragment_6[i]);
500 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset,
501 regs->elm_syndrome_fragment_5[i]);
502 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
503 regs->elm_syndrome_fragment_4[i]);
504 fallthrough;
505 case BCH8_ECC:
506 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
507 regs->elm_syndrome_fragment_3[i]);
508 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
509 regs->elm_syndrome_fragment_2[i]);
510 fallthrough;
511 case BCH4_ECC:
512 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
513 regs->elm_syndrome_fragment_1[i]);
514 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
515 regs->elm_syndrome_fragment_0[i]);
516 break;
517 default:
518 return -EINVAL;
519 }
520 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
521 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
522 regs->elm_syndrome_fragment_6[i] &
523 ELM_SYNDROME_VALID);
524 }
525 return 0;
526}
527
528static int elm_suspend(struct device *dev)
529{
530 struct elm_info *info = dev_get_drvdata(dev);
531 elm_context_save(info);
532 pm_runtime_put_sync(dev);
533 return 0;
534}
535
536static int elm_resume(struct device *dev)
537{
538 struct elm_info *info = dev_get_drvdata(dev);
539 pm_runtime_get_sync(dev);
540 elm_context_restore(info);
541 return 0;
542}
543#endif
544
545static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
546
547#ifdef CONFIG_OF
548static const struct of_device_id elm_of_match[] = {
549 { .compatible = "ti,am3352-elm" },
550 { .compatible = "ti,am64-elm" },
551 {},
552};
553MODULE_DEVICE_TABLE(of, elm_of_match);
554#endif
555
556static struct platform_driver elm_driver = {
557 .driver = {
558 .name = DRIVER_NAME,
559 .of_match_table = of_match_ptr(elm_of_match),
560 .pm = &elm_pm_ops,
561 },
562 .probe = elm_probe,
563 .remove_new = elm_remove,
564};
565
566module_platform_driver(elm_driver);
567
568MODULE_DESCRIPTION("ELM driver for BCH error correction");
569MODULE_AUTHOR("Texas Instruments");
570MODULE_ALIAS("platform:" DRIVER_NAME);
571MODULE_LICENSE("GPL v2");
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
68struct 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
82struct 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
93static LIST_HEAD(elm_devices);
94
95static void elm_write_reg(struct elm_info *info, int offset, u32 val)
96{
97 writel(val, info->elm_base + offset);
98}
99
100static 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 */
110int 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 -EPROBE_DEFER;
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}
139EXPORT_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 */
149static 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 */
171static 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 */
257static 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 */
289static 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 */
346void 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}
371EXPORT_SYMBOL(elm_decode_bch_error_page);
372
373static 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
391static 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 %pr\n", irq);
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
436static 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 */
448static 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 */
494static 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
536static 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
544static 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
553static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
554
555#ifdef CONFIG_OF
556static const struct of_device_id elm_of_match[] = {
557 { .compatible = "ti,am3352-elm" },
558 {},
559};
560MODULE_DEVICE_TABLE(of, elm_of_match);
561#endif
562
563static struct platform_driver elm_driver = {
564 .driver = {
565 .name = DRIVER_NAME,
566 .of_match_table = of_match_ptr(elm_of_match),
567 .pm = &elm_pm_ops,
568 },
569 .probe = elm_probe,
570 .remove = elm_remove,
571};
572
573module_platform_driver(elm_driver);
574
575MODULE_DESCRIPTION("ELM driver for BCH error correction");
576MODULE_AUTHOR("Texas Instruments");
577MODULE_ALIAS("platform:" DRIVER_NAME);
578MODULE_LICENSE("GPL v2");