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
elm_write_reg(struct elm_info * info,int offset,u32 val)85 static void elm_write_reg(struct elm_info *info, int offset, u32 val)
86 {
87 writel(val, info->elm_base + offset);
88 }
89
elm_read_reg(struct elm_info * info,int offset)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 */
elm_config(struct device * dev,enum bch_ecc bch_type,int ecc_steps,int ecc_step_size,int ecc_syndrome_size)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 */
elm_configure_page_mode(struct elm_info * info,int index,bool enable)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 */
elm_load_syndrome(struct elm_info * info,struct elm_errorvec * err_vec,u8 * ecc)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 */
elm_start_processing(struct elm_info * info,struct elm_errorvec * err_vec)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 */
elm_error_correction(struct elm_info * info,struct elm_errorvec * err_vec)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 */
elm_decode_bch_error_page(struct device * dev,u8 * ecc_calc,struct elm_errorvec * err_vec)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
elm_isr(int this_irq,void * dev_id)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
elm_probe(struct platform_device * pdev)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_put_sync(&pdev->dev);
415 pm_runtime_disable(&pdev->dev);
416 dev_err(&pdev->dev, "can't enable clock\n");
417 return ret;
418 }
419
420 init_completion(&info->elm_completion);
421 INIT_LIST_HEAD(&info->list);
422 list_add(&info->list, &elm_devices);
423 platform_set_drvdata(pdev, info);
424 return ret;
425 }
426
elm_remove(struct platform_device * pdev)427 static int elm_remove(struct platform_device *pdev)
428 {
429 pm_runtime_put_sync(&pdev->dev);
430 pm_runtime_disable(&pdev->dev);
431 return 0;
432 }
433
434 #ifdef CONFIG_PM_SLEEP
435 /**
436 * elm_context_save
437 * saves ELM configurations to preserve them across Hardware powered-down
438 */
elm_context_save(struct elm_info * info)439 static int elm_context_save(struct elm_info *info)
440 {
441 struct elm_registers *regs = &info->elm_regs;
442 enum bch_ecc bch_type = info->bch_type;
443 u32 offset = 0, i;
444
445 regs->elm_irqenable = elm_read_reg(info, ELM_IRQENABLE);
446 regs->elm_sysconfig = elm_read_reg(info, ELM_SYSCONFIG);
447 regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
448 regs->elm_page_ctrl = elm_read_reg(info, ELM_PAGE_CTRL);
449 for (i = 0; i < ERROR_VECTOR_MAX; i++) {
450 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
451 switch (bch_type) {
452 case BCH16_ECC:
453 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
454 ELM_SYNDROME_FRAGMENT_6 + offset);
455 regs->elm_syndrome_fragment_5[i] = elm_read_reg(info,
456 ELM_SYNDROME_FRAGMENT_5 + offset);
457 regs->elm_syndrome_fragment_4[i] = elm_read_reg(info,
458 ELM_SYNDROME_FRAGMENT_4 + offset);
459 fallthrough;
460 case BCH8_ECC:
461 regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
462 ELM_SYNDROME_FRAGMENT_3 + offset);
463 regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
464 ELM_SYNDROME_FRAGMENT_2 + offset);
465 fallthrough;
466 case BCH4_ECC:
467 regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
468 ELM_SYNDROME_FRAGMENT_1 + offset);
469 regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
470 ELM_SYNDROME_FRAGMENT_0 + offset);
471 break;
472 default:
473 return -EINVAL;
474 }
475 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
476 * to be saved for all BCH schemes*/
477 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
478 ELM_SYNDROME_FRAGMENT_6 + offset);
479 }
480 return 0;
481 }
482
483 /**
484 * elm_context_restore
485 * writes configurations saved duing power-down back into ELM registers
486 */
elm_context_restore(struct elm_info * info)487 static int elm_context_restore(struct elm_info *info)
488 {
489 struct elm_registers *regs = &info->elm_regs;
490 enum bch_ecc bch_type = info->bch_type;
491 u32 offset = 0, i;
492
493 elm_write_reg(info, ELM_IRQENABLE, regs->elm_irqenable);
494 elm_write_reg(info, ELM_SYSCONFIG, regs->elm_sysconfig);
495 elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
496 elm_write_reg(info, ELM_PAGE_CTRL, regs->elm_page_ctrl);
497 for (i = 0; i < ERROR_VECTOR_MAX; i++) {
498 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
499 switch (bch_type) {
500 case BCH16_ECC:
501 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
502 regs->elm_syndrome_fragment_6[i]);
503 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset,
504 regs->elm_syndrome_fragment_5[i]);
505 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
506 regs->elm_syndrome_fragment_4[i]);
507 fallthrough;
508 case BCH8_ECC:
509 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
510 regs->elm_syndrome_fragment_3[i]);
511 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
512 regs->elm_syndrome_fragment_2[i]);
513 fallthrough;
514 case BCH4_ECC:
515 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
516 regs->elm_syndrome_fragment_1[i]);
517 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
518 regs->elm_syndrome_fragment_0[i]);
519 break;
520 default:
521 return -EINVAL;
522 }
523 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
524 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
525 regs->elm_syndrome_fragment_6[i] &
526 ELM_SYNDROME_VALID);
527 }
528 return 0;
529 }
530
elm_suspend(struct device * dev)531 static int elm_suspend(struct device *dev)
532 {
533 struct elm_info *info = dev_get_drvdata(dev);
534 elm_context_save(info);
535 pm_runtime_put_sync(dev);
536 return 0;
537 }
538
elm_resume(struct device * dev)539 static int elm_resume(struct device *dev)
540 {
541 struct elm_info *info = dev_get_drvdata(dev);
542 pm_runtime_get_sync(dev);
543 elm_context_restore(info);
544 return 0;
545 }
546 #endif
547
548 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
549
550 #ifdef CONFIG_OF
551 static const struct of_device_id elm_of_match[] = {
552 { .compatible = "ti,am3352-elm" },
553 {},
554 };
555 MODULE_DEVICE_TABLE(of, elm_of_match);
556 #endif
557
558 static struct platform_driver elm_driver = {
559 .driver = {
560 .name = DRIVER_NAME,
561 .of_match_table = of_match_ptr(elm_of_match),
562 .pm = &elm_pm_ops,
563 },
564 .probe = elm_probe,
565 .remove = elm_remove,
566 };
567
568 module_platform_driver(elm_driver);
569
570 MODULE_DESCRIPTION("ELM driver for BCH error correction");
571 MODULE_AUTHOR("Texas Instruments");
572 MODULE_ALIAS("platform:" DRIVER_NAME);
573 MODULE_LICENSE("GPL v2");
574