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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