1 /*
2 * drivers/rtc/rtc-pl031.c
3 *
4 * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
5 *
6 * Author: Deepak Saxena <dsaxena@plexity.net>
7 *
8 * Copyright 2006 (c) MontaVista Software, Inc.
9 *
10 * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
11 * Copyright 2010 (c) ST-Ericsson AB
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 */
18 #include <linux/module.h>
19 #include <linux/rtc.h>
20 #include <linux/init.h>
21 #include <linux/interrupt.h>
22 #include <linux/amba/bus.h>
23 #include <linux/io.h>
24 #include <linux/bcd.h>
25 #include <linux/delay.h>
26 #include <linux/pm_wakeirq.h>
27 #include <linux/slab.h>
28
29 /*
30 * Register definitions
31 */
32 #define RTC_DR 0x00 /* Data read register */
33 #define RTC_MR 0x04 /* Match register */
34 #define RTC_LR 0x08 /* Data load register */
35 #define RTC_CR 0x0c /* Control register */
36 #define RTC_IMSC 0x10 /* Interrupt mask and set register */
37 #define RTC_RIS 0x14 /* Raw interrupt status register */
38 #define RTC_MIS 0x18 /* Masked interrupt status register */
39 #define RTC_ICR 0x1c /* Interrupt clear register */
40 /* ST variants have additional timer functionality */
41 #define RTC_TDR 0x20 /* Timer data read register */
42 #define RTC_TLR 0x24 /* Timer data load register */
43 #define RTC_TCR 0x28 /* Timer control register */
44 #define RTC_YDR 0x30 /* Year data read register */
45 #define RTC_YMR 0x34 /* Year match register */
46 #define RTC_YLR 0x38 /* Year data load register */
47
48 #define RTC_CR_EN (1 << 0) /* counter enable bit */
49 #define RTC_CR_CWEN (1 << 26) /* Clockwatch enable bit */
50
51 #define RTC_TCR_EN (1 << 1) /* Periodic timer enable bit */
52
53 /* Common bit definitions for Interrupt status and control registers */
54 #define RTC_BIT_AI (1 << 0) /* Alarm interrupt bit */
55 #define RTC_BIT_PI (1 << 1) /* Periodic interrupt bit. ST variants only. */
56
57 /* Common bit definations for ST v2 for reading/writing time */
58 #define RTC_SEC_SHIFT 0
59 #define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
60 #define RTC_MIN_SHIFT 6
61 #define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
62 #define RTC_HOUR_SHIFT 12
63 #define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
64 #define RTC_WDAY_SHIFT 17
65 #define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
66 #define RTC_MDAY_SHIFT 20
67 #define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
68 #define RTC_MON_SHIFT 25
69 #define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */
70
71 #define RTC_TIMER_FREQ 32768
72
73 /**
74 * struct pl031_vendor_data - per-vendor variations
75 * @ops: the vendor-specific operations used on this silicon version
76 * @clockwatch: if this is an ST Microelectronics silicon version with a
77 * clockwatch function
78 * @st_weekday: if this is an ST Microelectronics silicon version that need
79 * the weekday fix
80 * @irqflags: special IRQ flags per variant
81 */
82 struct pl031_vendor_data {
83 struct rtc_class_ops ops;
84 bool clockwatch;
85 bool st_weekday;
86 unsigned long irqflags;
87 };
88
89 struct pl031_local {
90 struct pl031_vendor_data *vendor;
91 struct rtc_device *rtc;
92 void __iomem *base;
93 };
94
pl031_alarm_irq_enable(struct device * dev,unsigned int enabled)95 static int pl031_alarm_irq_enable(struct device *dev,
96 unsigned int enabled)
97 {
98 struct pl031_local *ldata = dev_get_drvdata(dev);
99 unsigned long imsc;
100
101 /* Clear any pending alarm interrupts. */
102 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
103
104 imsc = readl(ldata->base + RTC_IMSC);
105
106 if (enabled == 1)
107 writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
108 else
109 writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);
110
111 return 0;
112 }
113
114 /*
115 * Convert Gregorian date to ST v2 RTC format.
116 */
pl031_stv2_tm_to_time(struct device * dev,struct rtc_time * tm,unsigned long * st_time,unsigned long * bcd_year)117 static int pl031_stv2_tm_to_time(struct device *dev,
118 struct rtc_time *tm, unsigned long *st_time,
119 unsigned long *bcd_year)
120 {
121 int year = tm->tm_year + 1900;
122 int wday = tm->tm_wday;
123
124 /* wday masking is not working in hardware so wday must be valid */
125 if (wday < -1 || wday > 6) {
126 dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
127 return -EINVAL;
128 } else if (wday == -1) {
129 /* wday is not provided, calculate it here */
130 unsigned long time;
131 struct rtc_time calc_tm;
132
133 rtc_tm_to_time(tm, &time);
134 rtc_time_to_tm(time, &calc_tm);
135 wday = calc_tm.tm_wday;
136 }
137
138 *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
139
140 *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
141 | (tm->tm_mday << RTC_MDAY_SHIFT)
142 | ((wday + 1) << RTC_WDAY_SHIFT)
143 | (tm->tm_hour << RTC_HOUR_SHIFT)
144 | (tm->tm_min << RTC_MIN_SHIFT)
145 | (tm->tm_sec << RTC_SEC_SHIFT);
146
147 return 0;
148 }
149
150 /*
151 * Convert ST v2 RTC format to Gregorian date.
152 */
pl031_stv2_time_to_tm(unsigned long st_time,unsigned long bcd_year,struct rtc_time * tm)153 static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
154 struct rtc_time *tm)
155 {
156 tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
157 tm->tm_mon = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
158 tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
159 tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
160 tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
161 tm->tm_min = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
162 tm->tm_sec = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
163
164 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
165 tm->tm_year -= 1900;
166
167 return 0;
168 }
169
pl031_stv2_read_time(struct device * dev,struct rtc_time * tm)170 static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
171 {
172 struct pl031_local *ldata = dev_get_drvdata(dev);
173
174 pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
175 readl(ldata->base + RTC_YDR), tm);
176
177 return 0;
178 }
179
pl031_stv2_set_time(struct device * dev,struct rtc_time * tm)180 static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
181 {
182 unsigned long time;
183 unsigned long bcd_year;
184 struct pl031_local *ldata = dev_get_drvdata(dev);
185 int ret;
186
187 ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
188 if (ret == 0) {
189 writel(bcd_year, ldata->base + RTC_YLR);
190 writel(time, ldata->base + RTC_LR);
191 }
192
193 return ret;
194 }
195
pl031_stv2_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)196 static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
197 {
198 struct pl031_local *ldata = dev_get_drvdata(dev);
199 int ret;
200
201 ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
202 readl(ldata->base + RTC_YMR), &alarm->time);
203
204 alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
205 alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
206
207 return ret;
208 }
209
pl031_stv2_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)210 static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
211 {
212 struct pl031_local *ldata = dev_get_drvdata(dev);
213 unsigned long time;
214 unsigned long bcd_year;
215 int ret;
216
217 /* At the moment, we can only deal with non-wildcarded alarm times. */
218 ret = rtc_valid_tm(&alarm->time);
219 if (ret == 0) {
220 ret = pl031_stv2_tm_to_time(dev, &alarm->time,
221 &time, &bcd_year);
222 if (ret == 0) {
223 writel(bcd_year, ldata->base + RTC_YMR);
224 writel(time, ldata->base + RTC_MR);
225
226 pl031_alarm_irq_enable(dev, alarm->enabled);
227 }
228 }
229
230 return ret;
231 }
232
pl031_interrupt(int irq,void * dev_id)233 static irqreturn_t pl031_interrupt(int irq, void *dev_id)
234 {
235 struct pl031_local *ldata = dev_id;
236 unsigned long rtcmis;
237 unsigned long events = 0;
238
239 rtcmis = readl(ldata->base + RTC_MIS);
240 if (rtcmis & RTC_BIT_AI) {
241 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
242 events |= (RTC_AF | RTC_IRQF);
243 rtc_update_irq(ldata->rtc, 1, events);
244
245 return IRQ_HANDLED;
246 }
247
248 return IRQ_NONE;
249 }
250
pl031_read_time(struct device * dev,struct rtc_time * tm)251 static int pl031_read_time(struct device *dev, struct rtc_time *tm)
252 {
253 struct pl031_local *ldata = dev_get_drvdata(dev);
254
255 rtc_time_to_tm(readl(ldata->base + RTC_DR), tm);
256
257 return 0;
258 }
259
pl031_set_time(struct device * dev,struct rtc_time * tm)260 static int pl031_set_time(struct device *dev, struct rtc_time *tm)
261 {
262 unsigned long time;
263 struct pl031_local *ldata = dev_get_drvdata(dev);
264 int ret;
265
266 ret = rtc_tm_to_time(tm, &time);
267
268 if (ret == 0)
269 writel(time, ldata->base + RTC_LR);
270
271 return ret;
272 }
273
pl031_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)274 static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
275 {
276 struct pl031_local *ldata = dev_get_drvdata(dev);
277
278 rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
279
280 alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
281 alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
282
283 return 0;
284 }
285
pl031_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)286 static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
287 {
288 struct pl031_local *ldata = dev_get_drvdata(dev);
289 unsigned long time;
290 int ret;
291
292 /* At the moment, we can only deal with non-wildcarded alarm times. */
293 ret = rtc_valid_tm(&alarm->time);
294 if (ret == 0) {
295 ret = rtc_tm_to_time(&alarm->time, &time);
296 if (ret == 0) {
297 writel(time, ldata->base + RTC_MR);
298 pl031_alarm_irq_enable(dev, alarm->enabled);
299 }
300 }
301
302 return ret;
303 }
304
pl031_remove(struct amba_device * adev)305 static int pl031_remove(struct amba_device *adev)
306 {
307 struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
308
309 dev_pm_clear_wake_irq(&adev->dev);
310 device_init_wakeup(&adev->dev, false);
311 if (adev->irq[0])
312 free_irq(adev->irq[0], ldata);
313 rtc_device_unregister(ldata->rtc);
314 amba_release_regions(adev);
315
316 return 0;
317 }
318
pl031_probe(struct amba_device * adev,const struct amba_id * id)319 static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
320 {
321 int ret;
322 struct pl031_local *ldata;
323 struct pl031_vendor_data *vendor = id->data;
324 struct rtc_class_ops *ops;
325 unsigned long time, data;
326
327 ret = amba_request_regions(adev, NULL);
328 if (ret)
329 goto err_req;
330
331 ldata = devm_kzalloc(&adev->dev, sizeof(struct pl031_local),
332 GFP_KERNEL);
333 ops = devm_kmemdup(&adev->dev, &vendor->ops, sizeof(vendor->ops),
334 GFP_KERNEL);
335 if (!ldata || !ops) {
336 ret = -ENOMEM;
337 goto out;
338 }
339
340 ldata->vendor = vendor;
341 ldata->base = devm_ioremap(&adev->dev, adev->res.start,
342 resource_size(&adev->res));
343 if (!ldata->base) {
344 ret = -ENOMEM;
345 goto out;
346 }
347
348 amba_set_drvdata(adev, ldata);
349
350 dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev));
351 dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev));
352
353 data = readl(ldata->base + RTC_CR);
354 /* Enable the clockwatch on ST Variants */
355 if (vendor->clockwatch)
356 data |= RTC_CR_CWEN;
357 else
358 data |= RTC_CR_EN;
359 writel(data, ldata->base + RTC_CR);
360
361 /*
362 * On ST PL031 variants, the RTC reset value does not provide correct
363 * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
364 */
365 if (vendor->st_weekday) {
366 if (readl(ldata->base + RTC_YDR) == 0x2000) {
367 time = readl(ldata->base + RTC_DR);
368 if ((time &
369 (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
370 == 0x02120000) {
371 time = time | (0x7 << RTC_WDAY_SHIFT);
372 writel(0x2000, ldata->base + RTC_YLR);
373 writel(time, ldata->base + RTC_LR);
374 }
375 }
376 }
377
378 if (!adev->irq[0]) {
379 /* When there's no interrupt, no point in exposing the alarm */
380 ops->read_alarm = NULL;
381 ops->set_alarm = NULL;
382 ops->alarm_irq_enable = NULL;
383 }
384
385 device_init_wakeup(&adev->dev, true);
386 ldata->rtc = rtc_device_register("pl031", &adev->dev, ops,
387 THIS_MODULE);
388 if (IS_ERR(ldata->rtc)) {
389 ret = PTR_ERR(ldata->rtc);
390 goto out;
391 }
392
393 if (adev->irq[0]) {
394 ret = request_irq(adev->irq[0], pl031_interrupt,
395 vendor->irqflags, "rtc-pl031", ldata);
396 if (ret)
397 goto out_no_irq;
398 dev_pm_set_wake_irq(&adev->dev, adev->irq[0]);
399 }
400 return 0;
401
402 out_no_irq:
403 rtc_device_unregister(ldata->rtc);
404 out:
405 amba_release_regions(adev);
406 err_req:
407
408 return ret;
409 }
410
411 /* Operations for the original ARM version */
412 static struct pl031_vendor_data arm_pl031 = {
413 .ops = {
414 .read_time = pl031_read_time,
415 .set_time = pl031_set_time,
416 .read_alarm = pl031_read_alarm,
417 .set_alarm = pl031_set_alarm,
418 .alarm_irq_enable = pl031_alarm_irq_enable,
419 },
420 };
421
422 /* The First ST derivative */
423 static struct pl031_vendor_data stv1_pl031 = {
424 .ops = {
425 .read_time = pl031_read_time,
426 .set_time = pl031_set_time,
427 .read_alarm = pl031_read_alarm,
428 .set_alarm = pl031_set_alarm,
429 .alarm_irq_enable = pl031_alarm_irq_enable,
430 },
431 .clockwatch = true,
432 .st_weekday = true,
433 };
434
435 /* And the second ST derivative */
436 static struct pl031_vendor_data stv2_pl031 = {
437 .ops = {
438 .read_time = pl031_stv2_read_time,
439 .set_time = pl031_stv2_set_time,
440 .read_alarm = pl031_stv2_read_alarm,
441 .set_alarm = pl031_stv2_set_alarm,
442 .alarm_irq_enable = pl031_alarm_irq_enable,
443 },
444 .clockwatch = true,
445 .st_weekday = true,
446 /*
447 * This variant shares the IRQ with another block and must not
448 * suspend that IRQ line.
449 * TODO check if it shares with IRQF_NO_SUSPEND user, else we can
450 * remove IRQF_COND_SUSPEND
451 */
452 .irqflags = IRQF_SHARED | IRQF_COND_SUSPEND,
453 };
454
455 static const struct amba_id pl031_ids[] = {
456 {
457 .id = 0x00041031,
458 .mask = 0x000fffff,
459 .data = &arm_pl031,
460 },
461 /* ST Micro variants */
462 {
463 .id = 0x00180031,
464 .mask = 0x00ffffff,
465 .data = &stv1_pl031,
466 },
467 {
468 .id = 0x00280031,
469 .mask = 0x00ffffff,
470 .data = &stv2_pl031,
471 },
472 {0, 0},
473 };
474
475 MODULE_DEVICE_TABLE(amba, pl031_ids);
476
477 static struct amba_driver pl031_driver = {
478 .drv = {
479 .name = "rtc-pl031",
480 },
481 .id_table = pl031_ids,
482 .probe = pl031_probe,
483 .remove = pl031_remove,
484 };
485
486 module_amba_driver(pl031_driver);
487
488 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
489 MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
490 MODULE_LICENSE("GPL");
491