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rtc-pl031.c
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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 <[email protected]>
7  *
8  * Copyright 2006 (c) MontaVista Software, Inc.
9  *
10  * Author: Mian Yousaf Kaukab <[email protected]>
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_CWEN (1 << 26) /* Clockwatch enable bit */
48 
49 #define RTC_TCR_EN (1 << 1) /* Periodic timer enable bit */
50 
51 /* Common bit definitions for Interrupt status and control registers */
52 #define RTC_BIT_AI (1 << 0) /* Alarm interrupt bit */
53 #define RTC_BIT_PI (1 << 1) /* Periodic interrupt bit. ST variants only. */
54 
55 /* Common bit definations for ST v2 for reading/writing time */
56 #define RTC_SEC_SHIFT 0
57 #define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
58 #define RTC_MIN_SHIFT 6
59 #define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
60 #define RTC_HOUR_SHIFT 12
61 #define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
62 #define RTC_WDAY_SHIFT 17
63 #define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
64 #define RTC_MDAY_SHIFT 20
65 #define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
66 #define RTC_MON_SHIFT 25
67 #define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */
68 
69 #define RTC_TIMER_FREQ 32768
70 
82  bool clockwatch;
83  bool st_weekday;
84  unsigned long irqflags;
85 };
86 
87 struct pl031_local {
89  struct rtc_device *rtc;
90  void __iomem *base;
91 };
92 
93 static int pl031_alarm_irq_enable(struct device *dev,
94  unsigned int enabled)
95 {
96  struct pl031_local *ldata = dev_get_drvdata(dev);
97  unsigned long imsc;
98 
99  /* Clear any pending alarm interrupts. */
100  writel(RTC_BIT_AI, ldata->base + RTC_ICR);
101 
102  imsc = readl(ldata->base + RTC_IMSC);
103 
104  if (enabled == 1)
105  writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
106  else
107  writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);
108 
109  return 0;
110 }
111 
112 /*
113  * Convert Gregorian date to ST v2 RTC format.
114  */
115 static int pl031_stv2_tm_to_time(struct device *dev,
116  struct rtc_time *tm, unsigned long *st_time,
117  unsigned long *bcd_year)
118 {
119  int year = tm->tm_year + 1900;
120  int wday = tm->tm_wday;
121 
122  /* wday masking is not working in hardware so wday must be valid */
123  if (wday < -1 || wday > 6) {
124  dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
125  return -EINVAL;
126  } else if (wday == -1) {
127  /* wday is not provided, calculate it here */
128  unsigned long time;
129  struct rtc_time calc_tm;
130 
131  rtc_tm_to_time(tm, &time);
132  rtc_time_to_tm(time, &calc_tm);
133  wday = calc_tm.tm_wday;
134  }
135 
136  *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
137 
138  *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
139  | (tm->tm_mday << RTC_MDAY_SHIFT)
140  | ((wday + 1) << RTC_WDAY_SHIFT)
141  | (tm->tm_hour << RTC_HOUR_SHIFT)
142  | (tm->tm_min << RTC_MIN_SHIFT)
143  | (tm->tm_sec << RTC_SEC_SHIFT);
144 
145  return 0;
146 }
147 
148 /*
149  * Convert ST v2 RTC format to Gregorian date.
150  */
151 static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
152  struct rtc_time *tm)
153 {
154  tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
155  tm->tm_mon = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
156  tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
157  tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
158  tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
159  tm->tm_min = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
160  tm->tm_sec = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
161 
162  tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
163  tm->tm_year -= 1900;
164 
165  return 0;
166 }
167 
168 static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
169 {
170  struct pl031_local *ldata = dev_get_drvdata(dev);
171 
172  pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
173  readl(ldata->base + RTC_YDR), tm);
174 
175  return 0;
176 }
177 
178 static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
179 {
180  unsigned long time;
181  unsigned long bcd_year;
182  struct pl031_local *ldata = dev_get_drvdata(dev);
183  int ret;
184 
185  ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
186  if (ret == 0) {
187  writel(bcd_year, ldata->base + RTC_YLR);
188  writel(time, ldata->base + RTC_LR);
189  }
190 
191  return ret;
192 }
193 
194 static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
195 {
196  struct pl031_local *ldata = dev_get_drvdata(dev);
197  int ret;
198 
199  ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
200  readl(ldata->base + RTC_YMR), &alarm->time);
201 
202  alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
203  alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
204 
205  return ret;
206 }
207 
208 static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
209 {
210  struct pl031_local *ldata = dev_get_drvdata(dev);
211  unsigned long time;
212  unsigned long bcd_year;
213  int ret;
214 
215  /* At the moment, we can only deal with non-wildcarded alarm times. */
216  ret = rtc_valid_tm(&alarm->time);
217  if (ret == 0) {
218  ret = pl031_stv2_tm_to_time(dev, &alarm->time,
219  &time, &bcd_year);
220  if (ret == 0) {
221  writel(bcd_year, ldata->base + RTC_YMR);
222  writel(time, ldata->base + RTC_MR);
223 
224  pl031_alarm_irq_enable(dev, alarm->enabled);
225  }
226  }
227 
228  return ret;
229 }
230 
231 static irqreturn_t pl031_interrupt(int irq, void *dev_id)
232 {
233  struct pl031_local *ldata = dev_id;
234  unsigned long rtcmis;
235  unsigned long events = 0;
236 
237  rtcmis = readl(ldata->base + RTC_MIS);
238  if (rtcmis & RTC_BIT_AI) {
239  writel(RTC_BIT_AI, ldata->base + RTC_ICR);
240  events |= (RTC_AF | RTC_IRQF);
241  rtc_update_irq(ldata->rtc, 1, events);
242 
243  return IRQ_HANDLED;
244  }
245 
246  return IRQ_NONE;
247 }
248 
249 static int pl031_read_time(struct device *dev, struct rtc_time *tm)
250 {
251  struct pl031_local *ldata = dev_get_drvdata(dev);
252 
253  rtc_time_to_tm(readl(ldata->base + RTC_DR), tm);
254 
255  return 0;
256 }
257 
258 static int pl031_set_time(struct device *dev, struct rtc_time *tm)
259 {
260  unsigned long time;
261  struct pl031_local *ldata = dev_get_drvdata(dev);
262  int ret;
263 
264  ret = rtc_tm_to_time(tm, &time);
265 
266  if (ret == 0)
267  writel(time, ldata->base + RTC_LR);
268 
269  return ret;
270 }
271 
272 static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
273 {
274  struct pl031_local *ldata = dev_get_drvdata(dev);
275 
276  rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
277 
278  alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
279  alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
280 
281  return 0;
282 }
283 
284 static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
285 {
286  struct pl031_local *ldata = dev_get_drvdata(dev);
287  unsigned long time;
288  int ret;
289 
290  /* At the moment, we can only deal with non-wildcarded alarm times. */
291  ret = rtc_valid_tm(&alarm->time);
292  if (ret == 0) {
293  ret = rtc_tm_to_time(&alarm->time, &time);
294  if (ret == 0) {
295  writel(time, ldata->base + RTC_MR);
296  pl031_alarm_irq_enable(dev, alarm->enabled);
297  }
298  }
299 
300  return ret;
301 }
302 
303 static int pl031_remove(struct amba_device *adev)
304 {
305  struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
306 
307  amba_set_drvdata(adev, NULL);
308  free_irq(adev->irq[0], ldata->rtc);
309  rtc_device_unregister(ldata->rtc);
310  iounmap(ldata->base);
311  kfree(ldata);
312  amba_release_regions(adev);
313 
314  return 0;
315 }
316 
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;
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  /* Enable the clockwatch on ST Variants */
349  if (vendor->clockwatch)
350  writel(readl(ldata->base + RTC_CR) | RTC_CR_CWEN,
351  ldata->base + RTC_CR);
352 
353  /*
354  * On ST PL031 variants, the RTC reset value does not provide correct
355  * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
356  */
357  if (vendor->st_weekday) {
358  if (readl(ldata->base + RTC_YDR) == 0x2000) {
359  time = readl(ldata->base + RTC_DR);
360  if ((time &
362  == 0x02120000) {
363  time = time | (0x7 << RTC_WDAY_SHIFT);
364  writel(0x2000, ldata->base + RTC_YLR);
365  writel(time, ldata->base + RTC_LR);
366  }
367  }
368  }
369 
370  ldata->rtc = rtc_device_register("pl031", &adev->dev, ops,
371  THIS_MODULE);
372  if (IS_ERR(ldata->rtc)) {
373  ret = PTR_ERR(ldata->rtc);
374  goto out_no_rtc;
375  }
376 
377  if (request_irq(adev->irq[0], pl031_interrupt,
378  vendor->irqflags, "rtc-pl031", ldata)) {
379  ret = -EIO;
380  goto out_no_irq;
381  }
382 
383  return 0;
384 
385 out_no_irq:
386  rtc_device_unregister(ldata->rtc);
387 out_no_rtc:
388  iounmap(ldata->base);
389  amba_set_drvdata(adev, NULL);
390 out_no_remap:
391  kfree(ldata);
392 out:
393  amba_release_regions(adev);
394 err_req:
395 
396  return ret;
397 }
398 
399 /* Operations for the original ARM version */
400 static struct pl031_vendor_data arm_pl031 = {
401  .ops = {
402  .read_time = pl031_read_time,
403  .set_time = pl031_set_time,
404  .read_alarm = pl031_read_alarm,
405  .set_alarm = pl031_set_alarm,
406  .alarm_irq_enable = pl031_alarm_irq_enable,
407  },
408  .irqflags = IRQF_NO_SUSPEND,
409 };
410 
411 /* The First ST derivative */
412 static struct pl031_vendor_data stv1_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  .clockwatch = true,
421  .st_weekday = true,
422  .irqflags = IRQF_NO_SUSPEND,
423 };
424 
425 /* And the second ST derivative */
426 static struct pl031_vendor_data stv2_pl031 = {
427  .ops = {
428  .read_time = pl031_stv2_read_time,
429  .set_time = pl031_stv2_set_time,
430  .read_alarm = pl031_stv2_read_alarm,
431  .set_alarm = pl031_stv2_set_alarm,
432  .alarm_irq_enable = pl031_alarm_irq_enable,
433  },
434  .clockwatch = true,
435  .st_weekday = true,
436  /*
437  * This variant shares the IRQ with another block and must not
438  * suspend that IRQ line.
439  */
440  .irqflags = IRQF_SHARED | IRQF_NO_SUSPEND,
441 };
442 
443 static struct amba_id pl031_ids[] = {
444  {
445  .id = 0x00041031,
446  .mask = 0x000fffff,
447  .data = &arm_pl031,
448  },
449  /* ST Micro variants */
450  {
451  .id = 0x00180031,
452  .mask = 0x00ffffff,
453  .data = &stv1_pl031,
454  },
455  {
456  .id = 0x00280031,
457  .mask = 0x00ffffff,
458  .data = &stv2_pl031,
459  },
460  {0, 0},
461 };
462 
463 MODULE_DEVICE_TABLE(amba, pl031_ids);
464 
465 static struct amba_driver pl031_driver = {
466  .drv = {
467  .name = "rtc-pl031",
468  },
469  .id_table = pl031_ids,
470  .probe = pl031_probe,
471  .remove = pl031_remove,
472 };
473 
474 module_amba_driver(pl031_driver);
475 
476 MODULE_AUTHOR("Deepak Saxena <[email protected]");
477 MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
478 MODULE_LICENSE("GPL");