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