1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * drivers/rtc/rtc-pl031.c
4 *
5 * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
6 *
7 * Author: Deepak Saxena <dsaxena@plexity.net>
8 *
9 * Copyright 2006 (c) MontaVista Software, Inc.
10 *
11 * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
12 * Copyright 2010 (c) ST-Ericsson AB
13 */
14 #include <linux/module.h>
15 #include <linux/rtc.h>
16 #include <linux/init.h>
17 #include <linux/interrupt.h>
18 #include <linux/amba/bus.h>
19 #include <linux/io.h>
20 #include <linux/bcd.h>
21 #include <linux/delay.h>
22 #include <linux/pm_wakeirq.h>
23 #include <linux/slab.h>
24
25 /*
26 * Register definitions
27 */
28 #define RTC_DR 0x00 /* Data read register */
29 #define RTC_MR 0x04 /* Match register */
30 #define RTC_LR 0x08 /* Data load register */
31 #define RTC_CR 0x0c /* Control register */
32 #define RTC_IMSC 0x10 /* Interrupt mask and set register */
33 #define RTC_RIS 0x14 /* Raw interrupt status register */
34 #define RTC_MIS 0x18 /* Masked interrupt status register */
35 #define RTC_ICR 0x1c /* Interrupt clear register */
36 /* ST variants have additional timer functionality */
37 #define RTC_TDR 0x20 /* Timer data read register */
38 #define RTC_TLR 0x24 /* Timer data load register */
39 #define RTC_TCR 0x28 /* Timer control register */
40 #define RTC_YDR 0x30 /* Year data read register */
41 #define RTC_YMR 0x34 /* Year match register */
42 #define RTC_YLR 0x38 /* Year data load register */
43
44 #define RTC_CR_EN (1 << 0) /* counter enable bit */
45 #define RTC_CR_CWEN (1 << 26) /* Clockwatch enable bit */
46
47 #define RTC_TCR_EN (1 << 1) /* Periodic timer enable bit */
48
49 /* Common bit definitions for Interrupt status and control registers */
50 #define RTC_BIT_AI (1 << 0) /* Alarm interrupt bit */
51 #define RTC_BIT_PI (1 << 1) /* Periodic interrupt bit. ST variants only. */
52
53 /* Common bit definations for ST v2 for reading/writing time */
54 #define RTC_SEC_SHIFT 0
55 #define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
56 #define RTC_MIN_SHIFT 6
57 #define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
58 #define RTC_HOUR_SHIFT 12
59 #define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
60 #define RTC_WDAY_SHIFT 17
61 #define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
62 #define RTC_MDAY_SHIFT 20
63 #define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
64 #define RTC_MON_SHIFT 25
65 #define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */
66
67 #define RTC_TIMER_FREQ 32768
68
69 /**
70 * struct pl031_vendor_data - per-vendor variations
71 * @ops: the vendor-specific operations used on this silicon version
72 * @clockwatch: if this is an ST Microelectronics silicon version with a
73 * clockwatch function
74 * @st_weekday: if this is an ST Microelectronics silicon version that need
75 * the weekday fix
76 * @irqflags: special IRQ flags per variant
77 */
78 struct pl031_vendor_data {
79 struct rtc_class_ops ops;
80 bool clockwatch;
81 bool st_weekday;
82 unsigned long irqflags;
83 };
84
85 struct pl031_local {
86 struct pl031_vendor_data *vendor;
87 struct rtc_device *rtc;
88 void __iomem *base;
89 };
90
pl031_alarm_irq_enable(struct device * dev,unsigned int enabled)91 static int pl031_alarm_irq_enable(struct device *dev,
92 unsigned int enabled)
93 {
94 struct pl031_local *ldata = dev_get_drvdata(dev);
95 unsigned long imsc;
96
97 /* Clear any pending alarm interrupts. */
98 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
99
100 imsc = readl(ldata->base + RTC_IMSC);
101
102 if (enabled == 1)
103 writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
104 else
105 writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);
106
107 return 0;
108 }
109
110 /*
111 * Convert Gregorian date to ST v2 RTC format.
112 */
pl031_stv2_tm_to_time(struct device * dev,struct rtc_time * tm,unsigned long * st_time,unsigned long * bcd_year)113 static int pl031_stv2_tm_to_time(struct device *dev,
114 struct rtc_time *tm, unsigned long *st_time,
115 unsigned long *bcd_year)
116 {
117 int year = tm->tm_year + 1900;
118 int wday = tm->tm_wday;
119
120 /* wday masking is not working in hardware so wday must be valid */
121 if (wday < -1 || wday > 6) {
122 dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
123 return -EINVAL;
124 } else if (wday == -1) {
125 /* wday is not provided, calculate it here */
126 unsigned long time;
127 struct rtc_time calc_tm;
128
129 rtc_tm_to_time(tm, &time);
130 rtc_time_to_tm(time, &calc_tm);
131 wday = calc_tm.tm_wday;
132 }
133
134 *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
135
136 *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
137 | (tm->tm_mday << RTC_MDAY_SHIFT)
138 | ((wday + 1) << RTC_WDAY_SHIFT)
139 | (tm->tm_hour << RTC_HOUR_SHIFT)
140 | (tm->tm_min << RTC_MIN_SHIFT)
141 | (tm->tm_sec << RTC_SEC_SHIFT);
142
143 return 0;
144 }
145
146 /*
147 * Convert ST v2 RTC format to Gregorian date.
148 */
pl031_stv2_time_to_tm(unsigned long st_time,unsigned long bcd_year,struct rtc_time * tm)149 static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
150 struct rtc_time *tm)
151 {
152 tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
153 tm->tm_mon = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
154 tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
155 tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
156 tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
157 tm->tm_min = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
158 tm->tm_sec = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
159
160 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
161 tm->tm_year -= 1900;
162
163 return 0;
164 }
165
pl031_stv2_read_time(struct device * dev,struct rtc_time * tm)166 static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
167 {
168 struct pl031_local *ldata = dev_get_drvdata(dev);
169
170 pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
171 readl(ldata->base + RTC_YDR), tm);
172
173 return 0;
174 }
175
pl031_stv2_set_time(struct device * dev,struct rtc_time * tm)176 static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
177 {
178 unsigned long time;
179 unsigned long bcd_year;
180 struct pl031_local *ldata = dev_get_drvdata(dev);
181 int ret;
182
183 ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
184 if (ret == 0) {
185 writel(bcd_year, ldata->base + RTC_YLR);
186 writel(time, ldata->base + RTC_LR);
187 }
188
189 return ret;
190 }
191
pl031_stv2_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)192 static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
193 {
194 struct pl031_local *ldata = dev_get_drvdata(dev);
195 int ret;
196
197 ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
198 readl(ldata->base + RTC_YMR), &alarm->time);
199
200 alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
201 alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
202
203 return ret;
204 }
205
pl031_stv2_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)206 static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
207 {
208 struct pl031_local *ldata = dev_get_drvdata(dev);
209 unsigned long time;
210 unsigned long bcd_year;
211 int ret;
212
213 /* At the moment, we can only deal with non-wildcarded alarm times. */
214 ret = rtc_valid_tm(&alarm->time);
215 if (ret == 0) {
216 ret = pl031_stv2_tm_to_time(dev, &alarm->time,
217 &time, &bcd_year);
218 if (ret == 0) {
219 writel(bcd_year, ldata->base + RTC_YMR);
220 writel(time, ldata->base + RTC_MR);
221
222 pl031_alarm_irq_enable(dev, alarm->enabled);
223 }
224 }
225
226 return ret;
227 }
228
pl031_interrupt(int irq,void * dev_id)229 static irqreturn_t pl031_interrupt(int irq, void *dev_id)
230 {
231 struct pl031_local *ldata = dev_id;
232 unsigned long rtcmis;
233 unsigned long events = 0;
234
235 rtcmis = readl(ldata->base + RTC_MIS);
236 if (rtcmis & RTC_BIT_AI) {
237 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
238 events |= (RTC_AF | RTC_IRQF);
239 rtc_update_irq(ldata->rtc, 1, events);
240
241 return IRQ_HANDLED;
242 }
243
244 return IRQ_NONE;
245 }
246
pl031_read_time(struct device * dev,struct rtc_time * tm)247 static int pl031_read_time(struct device *dev, struct rtc_time *tm)
248 {
249 struct pl031_local *ldata = dev_get_drvdata(dev);
250
251 rtc_time_to_tm(readl(ldata->base + RTC_DR), tm);
252
253 return 0;
254 }
255
pl031_set_time(struct device * dev,struct rtc_time * tm)256 static int pl031_set_time(struct device *dev, struct rtc_time *tm)
257 {
258 unsigned long time;
259 struct pl031_local *ldata = dev_get_drvdata(dev);
260 int ret;
261
262 ret = rtc_tm_to_time(tm, &time);
263
264 if (ret == 0)
265 writel(time, ldata->base + RTC_LR);
266
267 return ret;
268 }
269
pl031_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)270 static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
271 {
272 struct pl031_local *ldata = dev_get_drvdata(dev);
273
274 rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
275
276 alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
277 alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
278
279 return 0;
280 }
281
pl031_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)282 static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
283 {
284 struct pl031_local *ldata = dev_get_drvdata(dev);
285 unsigned long time;
286 int ret;
287
288 /* At the moment, we can only deal with non-wildcarded alarm times. */
289 ret = rtc_valid_tm(&alarm->time);
290 if (ret == 0) {
291 ret = rtc_tm_to_time(&alarm->time, &time);
292 if (ret == 0) {
293 writel(time, ldata->base + RTC_MR);
294 pl031_alarm_irq_enable(dev, alarm->enabled);
295 }
296 }
297
298 return ret;
299 }
300
pl031_remove(struct amba_device * adev)301 static int pl031_remove(struct amba_device *adev)
302 {
303 struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
304
305 dev_pm_clear_wake_irq(&adev->dev);
306 device_init_wakeup(&adev->dev, false);
307 if (adev->irq[0])
308 free_irq(adev->irq[0], ldata);
309 amba_release_regions(adev);
310
311 return 0;
312 }
313
pl031_probe(struct amba_device * adev,const struct amba_id * id)314 static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
315 {
316 int ret;
317 struct pl031_local *ldata;
318 struct pl031_vendor_data *vendor = id->data;
319 struct rtc_class_ops *ops;
320 unsigned long time, data;
321
322 ret = amba_request_regions(adev, NULL);
323 if (ret)
324 goto err_req;
325
326 ldata = devm_kzalloc(&adev->dev, sizeof(struct pl031_local),
327 GFP_KERNEL);
328 ops = devm_kmemdup(&adev->dev, &vendor->ops, sizeof(vendor->ops),
329 GFP_KERNEL);
330 if (!ldata || !ops) {
331 ret = -ENOMEM;
332 goto out;
333 }
334
335 ldata->vendor = vendor;
336 ldata->base = devm_ioremap(&adev->dev, adev->res.start,
337 resource_size(&adev->res));
338 if (!ldata->base) {
339 ret = -ENOMEM;
340 goto out;
341 }
342
343 amba_set_drvdata(adev, ldata);
344
345 dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev));
346 dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev));
347
348 data = readl(ldata->base + RTC_CR);
349 /* Enable the clockwatch on ST Variants */
350 if (vendor->clockwatch)
351 data |= RTC_CR_CWEN;
352 else
353 data |= RTC_CR_EN;
354 writel(data, ldata->base + RTC_CR);
355
356 /*
357 * On ST PL031 variants, the RTC reset value does not provide correct
358 * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
359 */
360 if (vendor->st_weekday) {
361 if (readl(ldata->base + RTC_YDR) == 0x2000) {
362 time = readl(ldata->base + RTC_DR);
363 if ((time &
364 (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
365 == 0x02120000) {
366 time = time | (0x7 << RTC_WDAY_SHIFT);
367 writel(0x2000, ldata->base + RTC_YLR);
368 writel(time, ldata->base + RTC_LR);
369 }
370 }
371 }
372
373 if (!adev->irq[0]) {
374 /* When there's no interrupt, no point in exposing the alarm */
375 ops->read_alarm = NULL;
376 ops->set_alarm = NULL;
377 ops->alarm_irq_enable = NULL;
378 }
379
380 device_init_wakeup(&adev->dev, true);
381 ldata->rtc = devm_rtc_allocate_device(&adev->dev);
382 if (IS_ERR(ldata->rtc))
383 return PTR_ERR(ldata->rtc);
384
385 ldata->rtc->ops = ops;
386
387 ret = rtc_register_device(ldata->rtc);
388 if (ret)
389 goto out;
390
391 if (adev->irq[0]) {
392 ret = request_irq(adev->irq[0], pl031_interrupt,
393 vendor->irqflags, "rtc-pl031", ldata);
394 if (ret)
395 goto out;
396 dev_pm_set_wake_irq(&adev->dev, adev->irq[0]);
397 }
398 return 0;
399
400 out:
401 amba_release_regions(adev);
402 err_req:
403
404 return ret;
405 }
406
407 /* Operations for the original ARM version */
408 static struct pl031_vendor_data arm_pl031 = {
409 .ops = {
410 .read_time = pl031_read_time,
411 .set_time = pl031_set_time,
412 .read_alarm = pl031_read_alarm,
413 .set_alarm = pl031_set_alarm,
414 .alarm_irq_enable = pl031_alarm_irq_enable,
415 },
416 };
417
418 /* The First ST derivative */
419 static struct pl031_vendor_data stv1_pl031 = {
420 .ops = {
421 .read_time = pl031_read_time,
422 .set_time = pl031_set_time,
423 .read_alarm = pl031_read_alarm,
424 .set_alarm = pl031_set_alarm,
425 .alarm_irq_enable = pl031_alarm_irq_enable,
426 },
427 .clockwatch = true,
428 .st_weekday = true,
429 };
430
431 /* And the second ST derivative */
432 static struct pl031_vendor_data stv2_pl031 = {
433 .ops = {
434 .read_time = pl031_stv2_read_time,
435 .set_time = pl031_stv2_set_time,
436 .read_alarm = pl031_stv2_read_alarm,
437 .set_alarm = pl031_stv2_set_alarm,
438 .alarm_irq_enable = pl031_alarm_irq_enable,
439 },
440 .clockwatch = true,
441 .st_weekday = true,
442 /*
443 * This variant shares the IRQ with another block and must not
444 * suspend that IRQ line.
445 * TODO check if it shares with IRQF_NO_SUSPEND user, else we can
446 * remove IRQF_COND_SUSPEND
447 */
448 .irqflags = IRQF_SHARED | IRQF_COND_SUSPEND,
449 };
450
451 static const struct amba_id pl031_ids[] = {
452 {
453 .id = 0x00041031,
454 .mask = 0x000fffff,
455 .data = &arm_pl031,
456 },
457 /* ST Micro variants */
458 {
459 .id = 0x00180031,
460 .mask = 0x00ffffff,
461 .data = &stv1_pl031,
462 },
463 {
464 .id = 0x00280031,
465 .mask = 0x00ffffff,
466 .data = &stv2_pl031,
467 },
468 {0, 0},
469 };
470
471 MODULE_DEVICE_TABLE(amba, pl031_ids);
472
473 static struct amba_driver pl031_driver = {
474 .drv = {
475 .name = "rtc-pl031",
476 },
477 .id_table = pl031_ids,
478 .probe = pl031_probe,
479 .remove = pl031_remove,
480 };
481
482 module_amba_driver(pl031_driver);
483
484 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
485 MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
486 MODULE_LICENSE("GPL");
487