1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Error Location Module
5 * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
8 #define DRIVER_NAME "omap-elm"
10 #include <linux/platform_device.h>
11 #include <linux/module.h>
12 #include <linux/interrupt.h>
15 #include <linux/sched.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/platform_data/elm.h>
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
34 /* ELM Interrupt Status Register */
35 #define INTR_STATUS_PAGE_VALID BIT(8)
37 /* ELM Interrupt Enable Register */
38 #define INTR_EN_PAGE_MASK BIT(8)
40 /* ELM Location Configuration Register */
41 #define ECC_BCH_LEVEL_MASK 0x3
44 #define ELM_SYNDROME_VALID BIT(16)
46 /* ELM_LOCATION_STATUS Register */
47 #define ECC_CORRECTABLE_MASK BIT(8)
48 #define ECC_NB_ERRORS_MASK 0x1f
50 /* ELM_ERROR_LOCATION_0-15 Registers */
51 #define ECC_ERROR_LOCATION_MASK 0x1fff
53 #define ELM_ECC_SIZE 0x7ff
55 #define SYNDROME_FRAGMENT_REG_SIZE 0x40
56 #define ERROR_LOCATION_SIZE 0x100
58 struct elm_registers {
61 u32 elm_location_config;
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];
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;
80 int ecc_syndrome_size;
83 static LIST_HEAD(elm_devices);
85 static void elm_write_reg(struct elm_info *info, int offset, u32 val)
87 writel(val, info->elm_base + offset);
90 static u32 elm_read_reg(struct elm_info *info, int offset)
92 return readl(info->elm_base + offset);
96 * elm_config - Configure ELM module
98 * @bch_type: Type of BCH ecc
100 int elm_config(struct device *dev, enum bch_ecc bch_type,
101 int ecc_steps, int ecc_step_size, int ecc_syndrome_size)
104 struct elm_info *info = dev_get_drvdata(dev);
107 dev_err(dev, "Unable to configure elm - device not probed?\n");
108 return -EPROBE_DEFER;
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);
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);
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;
129 EXPORT_SYMBOL(elm_config);
132 * elm_configure_page_mode - Enable/Disable page mode
134 * @index: index number of syndrome fragment vector
135 * @enable: enable/disable flag for page mode
137 * Enable page mode for syndrome fragment index
139 static void elm_configure_page_mode(struct elm_info *info, int index,
144 reg_val = elm_read_reg(info, ELM_PAGE_CTRL);
146 reg_val |= BIT(index); /* enable page mode */
148 reg_val &= ~BIT(index); /* disable page mode */
150 elm_write_reg(info, ELM_PAGE_CTRL, reg_val);
154 * elm_load_syndrome - Load ELM syndrome reg
156 * @err_vec: elm error vectors
157 * @ecc: buffer with calculated ecc
159 * Load syndrome fragment registers with calculated ecc in reverse order.
161 static void elm_load_syndrome(struct elm_info *info,
162 struct elm_errorvec *err_vec, u8 *ecc)
167 for (i = 0; i < info->ecc_steps; i++) {
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) {
176 /* syndrome fragment 0 = ecc[9-12B] */
177 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[9]);
178 elm_write_reg(info, offset, val);
180 /* syndrome fragment 1 = ecc[5-8B] */
182 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[5]);
183 elm_write_reg(info, offset, val);
185 /* syndrome fragment 2 = ecc[1-4B] */
187 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[1]);
188 elm_write_reg(info, offset, val);
190 /* syndrome fragment 3 = ecc[0B] */
193 elm_write_reg(info, offset, val);
196 /* syndrome fragment 0 = ecc[20-52b] bits */
197 val = ((__force u32)cpu_to_be32(*(u32 *)&ecc[3]) >> 4) |
198 ((ecc[2] & 0xf) << 28);
199 elm_write_reg(info, offset, val);
201 /* syndrome fragment 1 = ecc[0-20b] bits */
203 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[0]) >> 12;
204 elm_write_reg(info, offset, val);
207 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[22]);
208 elm_write_reg(info, offset, val);
210 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[18]);
211 elm_write_reg(info, offset, val);
213 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[14]);
214 elm_write_reg(info, offset, val);
216 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[10]);
217 elm_write_reg(info, offset, val);
219 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[6]);
220 elm_write_reg(info, offset, val);
222 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[2]);
223 elm_write_reg(info, offset, val);
225 val = (__force u32)cpu_to_be32(*(u32 *)&ecc[0]) >> 16;
226 elm_write_reg(info, offset, val);
229 pr_err("invalid config bch_type\n");
233 /* Update ecc pointer with ecc byte size */
234 ecc += info->ecc_syndrome_size;
239 * elm_start_processing - start elm syndrome processing
241 * @err_vec: elm error vectors
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.
247 static void elm_start_processing(struct elm_info *info,
248 struct elm_errorvec *err_vec)
254 * Set syndrome vector valid, so that ELM module
255 * will process it for vectors error is reported
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);
269 * elm_error_correction - locate correctable error position
271 * @err_vec: elm error vectors
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.
279 static void elm_error_correction(struct elm_info *info,
280 struct elm_errorvec *err_vec)
282 int i, j, errors = 0;
286 for (i = 0; i < info->ecc_steps; i++) {
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);
293 /* Check correctable error or not */
294 if (reg_val & ECC_CORRECTABLE_MASK) {
295 offset = ELM_ERROR_LOCATION_0 +
296 ERROR_LOCATION_SIZE * i;
298 /* Read count of correctable errors */
299 err_vec[i].error_count = reg_val &
302 /* Update the error locations in error vector */
303 for (j = 0; j < err_vec[i].error_count; j++) {
305 reg_val = elm_read_reg(info, offset);
306 err_vec[i].error_loc[j] = reg_val &
307 ECC_ERROR_LOCATION_MASK;
309 /* Update error location register */
313 errors += err_vec[i].error_count;
315 err_vec[i].error_uncorrectable = true;
318 /* Clearing interrupts for processed error vectors */
319 elm_write_reg(info, ELM_IRQSTATUS, BIT(i));
321 /* Disable page mode */
322 elm_configure_page_mode(info, i, false);
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
333 * Called with one or more error reported vectors & vectors with
334 * error reported is updated in err_vec[].error_reported
336 void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
337 struct elm_errorvec *err_vec)
339 struct elm_info *info = dev_get_drvdata(dev);
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);
347 /* Load valid ecc byte to syndrome fragment register */
348 elm_load_syndrome(info, err_vec, ecc_calc);
350 /* Enable syndrome processing for which syndrome fragment is updated */
351 elm_start_processing(info, err_vec);
353 /* Wait for ELM module to finish locating error correction */
354 wait_for_completion(&info->elm_completion);
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);
361 EXPORT_SYMBOL(elm_decode_bch_error_page);
363 static irqreturn_t elm_isr(int this_irq, void *dev_id)
366 struct elm_info *info = dev_id;
368 reg_val = elm_read_reg(info, ELM_IRQSTATUS);
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);
381 static int elm_probe(struct platform_device *pdev)
384 struct resource *res, *irq;
385 struct elm_info *info;
387 info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
391 info->dev = &pdev->dev;
393 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
395 dev_err(&pdev->dev, "no irq resource defined\n");
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);
404 ret = devm_request_irq(&pdev->dev, irq->start, elm_isr, 0,
407 dev_err(&pdev->dev, "failure requesting %pr\n", irq);
411 pm_runtime_enable(&pdev->dev);
412 if (pm_runtime_get_sync(&pdev->dev) < 0) {
414 pm_runtime_put_sync(&pdev->dev);
415 pm_runtime_disable(&pdev->dev);
416 dev_err(&pdev->dev, "can't enable clock\n");
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);
427 static int elm_remove(struct platform_device *pdev)
429 pm_runtime_put_sync(&pdev->dev);
430 pm_runtime_disable(&pdev->dev);
434 #ifdef CONFIG_PM_SLEEP
437 * saves ELM configurations to preserve them across Hardware powered-down
439 static int elm_context_save(struct elm_info *info)
441 struct elm_registers *regs = &info->elm_regs;
442 enum bch_ecc bch_type = info->bch_type;
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;
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);
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);
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);
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);
484 * elm_context_restore
485 * writes configurations saved duing power-down back into ELM registers
487 static int elm_context_restore(struct elm_info *info)
489 struct elm_registers *regs = &info->elm_regs;
490 enum bch_ecc bch_type = info->bch_type;
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;
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]);
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]);
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]);
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] &
531 static int elm_suspend(struct device *dev)
533 struct elm_info *info = dev_get_drvdata(dev);
534 elm_context_save(info);
535 pm_runtime_put_sync(dev);
539 static int elm_resume(struct device *dev)
541 struct elm_info *info = dev_get_drvdata(dev);
542 pm_runtime_get_sync(dev);
543 elm_context_restore(info);
548 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
551 static const struct of_device_id elm_of_match[] = {
552 { .compatible = "ti,am3352-elm" },
555 MODULE_DEVICE_TABLE(of, elm_of_match);
558 static struct platform_driver elm_driver = {
561 .of_match_table = of_match_ptr(elm_of_match),
565 .remove = elm_remove,
568 module_platform_driver(elm_driver);
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");