Version:  2.0.40 2.2.26 2.4.37 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8

Linux/drivers/rtc/rtc-mrst.c

  1 /*
  2  * rtc-mrst.c: Driver for Moorestown virtual RTC
  3  *
  4  * (C) Copyright 2009 Intel Corporation
  5  * Author: Jacob Pan (jacob.jun.pan@intel.com)
  6  *         Feng Tang (feng.tang@intel.com)
  7  *
  8  * This program is free software; you can redistribute it and/or
  9  * modify it under the terms of the GNU General Public License
 10  * as published by the Free Software Foundation; version 2
 11  * of the License.
 12  *
 13  * Note:
 14  * VRTC is emulated by system controller firmware, the real HW
 15  * RTC is located in the PMIC device. SCU FW shadows PMIC RTC
 16  * in a memory mapped IO space that is visible to the host IA
 17  * processor.
 18  *
 19  * This driver is based upon drivers/rtc/rtc-cmos.c
 20  */
 21 
 22 /*
 23  * Note:
 24  *  * vRTC only supports binary mode and 24H mode
 25  *  * vRTC only support PIE and AIE, no UIE, and its PIE only happens
 26  *    at 23:59:59pm everyday, no support for adjustable frequency
 27  *  * Alarm function is also limited to hr/min/sec.
 28  */
 29 
 30 #include <linux/mod_devicetable.h>
 31 #include <linux/platform_device.h>
 32 #include <linux/interrupt.h>
 33 #include <linux/spinlock.h>
 34 #include <linux/kernel.h>
 35 #include <linux/mc146818rtc.h>
 36 #include <linux/module.h>
 37 #include <linux/init.h>
 38 #include <linux/sfi.h>
 39 
 40 #include <asm/intel_scu_ipc.h>
 41 #include <asm/intel-mid.h>
 42 #include <asm/intel_mid_vrtc.h>
 43 
 44 struct mrst_rtc {
 45         struct rtc_device       *rtc;
 46         struct device           *dev;
 47         int                     irq;
 48         struct resource         *iomem;
 49 
 50         u8                      enabled_wake;
 51         u8                      suspend_ctrl;
 52 };
 53 
 54 static const char driver_name[] = "rtc_mrst";
 55 
 56 #define RTC_IRQMASK     (RTC_PF | RTC_AF)
 57 
 58 static inline int is_intr(u8 rtc_intr)
 59 {
 60         if (!(rtc_intr & RTC_IRQF))
 61                 return 0;
 62         return rtc_intr & RTC_IRQMASK;
 63 }
 64 
 65 static inline unsigned char vrtc_is_updating(void)
 66 {
 67         unsigned char uip;
 68         unsigned long flags;
 69 
 70         spin_lock_irqsave(&rtc_lock, flags);
 71         uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP);
 72         spin_unlock_irqrestore(&rtc_lock, flags);
 73         return uip;
 74 }
 75 
 76 /*
 77  * rtc_time's year contains the increment over 1900, but vRTC's YEAR
 78  * register can't be programmed to value larger than 0x64, so vRTC
 79  * driver chose to use 1972 (1970 is UNIX time start point) as the base,
 80  * and does the translation at read/write time.
 81  *
 82  * Why not just use 1970 as the offset? it's because using 1972 will
 83  * make it consistent in leap year setting for both vrtc and low-level
 84  * physical rtc devices. Then why not use 1960 as the offset? If we use
 85  * 1960, for a device's first use, its YEAR register is 0 and the system
 86  * year will be parsed as 1960 which is not a valid UNIX time and will
 87  * cause many applications to fail mysteriously.
 88  */
 89 static int mrst_read_time(struct device *dev, struct rtc_time *time)
 90 {
 91         unsigned long flags;
 92 
 93         if (vrtc_is_updating())
 94                 mdelay(20);
 95 
 96         spin_lock_irqsave(&rtc_lock, flags);
 97         time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
 98         time->tm_min = vrtc_cmos_read(RTC_MINUTES);
 99         time->tm_hour = vrtc_cmos_read(RTC_HOURS);
100         time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
101         time->tm_mon = vrtc_cmos_read(RTC_MONTH);
102         time->tm_year = vrtc_cmos_read(RTC_YEAR);
103         spin_unlock_irqrestore(&rtc_lock, flags);
104 
105         /* Adjust for the 1972/1900 */
106         time->tm_year += 72;
107         time->tm_mon--;
108         return rtc_valid_tm(time);
109 }
110 
111 static int mrst_set_time(struct device *dev, struct rtc_time *time)
112 {
113         int ret;
114         unsigned long flags;
115         unsigned char mon, day, hrs, min, sec;
116         unsigned int yrs;
117 
118         yrs = time->tm_year;
119         mon = time->tm_mon + 1;   /* tm_mon starts at zero */
120         day = time->tm_mday;
121         hrs = time->tm_hour;
122         min = time->tm_min;
123         sec = time->tm_sec;
124 
125         if (yrs < 72 || yrs > 138)
126                 return -EINVAL;
127         yrs -= 72;
128 
129         spin_lock_irqsave(&rtc_lock, flags);
130 
131         vrtc_cmos_write(yrs, RTC_YEAR);
132         vrtc_cmos_write(mon, RTC_MONTH);
133         vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
134         vrtc_cmos_write(hrs, RTC_HOURS);
135         vrtc_cmos_write(min, RTC_MINUTES);
136         vrtc_cmos_write(sec, RTC_SECONDS);
137 
138         spin_unlock_irqrestore(&rtc_lock, flags);
139 
140         ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
141         return ret;
142 }
143 
144 static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t)
145 {
146         struct mrst_rtc *mrst = dev_get_drvdata(dev);
147         unsigned char rtc_control;
148 
149         if (mrst->irq <= 0)
150                 return -EIO;
151 
152         /* vRTC only supports binary mode */
153         spin_lock_irq(&rtc_lock);
154         t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
155         t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
156         t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
157 
158         rtc_control = vrtc_cmos_read(RTC_CONTROL);
159         spin_unlock_irq(&rtc_lock);
160 
161         t->enabled = !!(rtc_control & RTC_AIE);
162         t->pending = 0;
163 
164         return 0;
165 }
166 
167 static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
168 {
169         unsigned char   rtc_intr;
170 
171         /*
172          * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
173          * allegedly some older rtcs need that to handle irqs properly
174          */
175         rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
176         rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
177         if (is_intr(rtc_intr))
178                 rtc_update_irq(mrst->rtc, 1, rtc_intr);
179 }
180 
181 static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
182 {
183         unsigned char   rtc_control;
184 
185         /*
186          * Flush any pending IRQ status, notably for update irqs,
187          * before we enable new IRQs
188          */
189         rtc_control = vrtc_cmos_read(RTC_CONTROL);
190         mrst_checkintr(mrst, rtc_control);
191 
192         rtc_control |= mask;
193         vrtc_cmos_write(rtc_control, RTC_CONTROL);
194 
195         mrst_checkintr(mrst, rtc_control);
196 }
197 
198 static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
199 {
200         unsigned char   rtc_control;
201 
202         rtc_control = vrtc_cmos_read(RTC_CONTROL);
203         rtc_control &= ~mask;
204         vrtc_cmos_write(rtc_control, RTC_CONTROL);
205         mrst_checkintr(mrst, rtc_control);
206 }
207 
208 static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t)
209 {
210         struct mrst_rtc *mrst = dev_get_drvdata(dev);
211         unsigned char hrs, min, sec;
212         int ret = 0;
213 
214         if (!mrst->irq)
215                 return -EIO;
216 
217         hrs = t->time.tm_hour;
218         min = t->time.tm_min;
219         sec = t->time.tm_sec;
220 
221         spin_lock_irq(&rtc_lock);
222         /* Next rtc irq must not be from previous alarm setting */
223         mrst_irq_disable(mrst, RTC_AIE);
224 
225         /* Update alarm */
226         vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
227         vrtc_cmos_write(min, RTC_MINUTES_ALARM);
228         vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
229 
230         spin_unlock_irq(&rtc_lock);
231 
232         ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
233         if (ret)
234                 return ret;
235 
236         spin_lock_irq(&rtc_lock);
237         if (t->enabled)
238                 mrst_irq_enable(mrst, RTC_AIE);
239 
240         spin_unlock_irq(&rtc_lock);
241 
242         return 0;
243 }
244 
245 /* Currently, the vRTC doesn't support UIE ON/OFF */
246 static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
247 {
248         struct mrst_rtc *mrst = dev_get_drvdata(dev);
249         unsigned long   flags;
250 
251         spin_lock_irqsave(&rtc_lock, flags);
252         if (enabled)
253                 mrst_irq_enable(mrst, RTC_AIE);
254         else
255                 mrst_irq_disable(mrst, RTC_AIE);
256         spin_unlock_irqrestore(&rtc_lock, flags);
257         return 0;
258 }
259 
260 
261 #if IS_ENABLED(CONFIG_RTC_INTF_PROC)
262 
263 static int mrst_procfs(struct device *dev, struct seq_file *seq)
264 {
265         unsigned char   rtc_control, valid;
266 
267         spin_lock_irq(&rtc_lock);
268         rtc_control = vrtc_cmos_read(RTC_CONTROL);
269         valid = vrtc_cmos_read(RTC_VALID);
270         spin_unlock_irq(&rtc_lock);
271 
272         seq_printf(seq,
273                    "periodic_IRQ\t: %s\n"
274                    "alarm\t\t: %s\n"
275                    "BCD\t\t: no\n"
276                    "periodic_freq\t: daily (not adjustable)\n",
277                    (rtc_control & RTC_PIE) ? "on" : "off",
278                    (rtc_control & RTC_AIE) ? "on" : "off");
279 
280         return 0;
281 }
282 
283 #else
284 #define mrst_procfs     NULL
285 #endif
286 
287 static const struct rtc_class_ops mrst_rtc_ops = {
288         .read_time      = mrst_read_time,
289         .set_time       = mrst_set_time,
290         .read_alarm     = mrst_read_alarm,
291         .set_alarm      = mrst_set_alarm,
292         .proc           = mrst_procfs,
293         .alarm_irq_enable = mrst_rtc_alarm_irq_enable,
294 };
295 
296 static struct mrst_rtc  mrst_rtc;
297 
298 /*
299  * When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
300  * Reg B, so no need for this driver to clear it
301  */
302 static irqreturn_t mrst_rtc_irq(int irq, void *p)
303 {
304         u8 irqstat;
305 
306         spin_lock(&rtc_lock);
307         /* This read will clear all IRQ flags inside Reg C */
308         irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
309         spin_unlock(&rtc_lock);
310 
311         irqstat &= RTC_IRQMASK | RTC_IRQF;
312         if (is_intr(irqstat)) {
313                 rtc_update_irq(p, 1, irqstat);
314                 return IRQ_HANDLED;
315         }
316         return IRQ_NONE;
317 }
318 
319 static int vrtc_mrst_do_probe(struct device *dev, struct resource *iomem,
320                               int rtc_irq)
321 {
322         int retval = 0;
323         unsigned char rtc_control;
324 
325         /* There can be only one ... */
326         if (mrst_rtc.dev)
327                 return -EBUSY;
328 
329         if (!iomem)
330                 return -ENODEV;
331 
332         iomem = request_mem_region(iomem->start, resource_size(iomem),
333                                    driver_name);
334         if (!iomem) {
335                 dev_dbg(dev, "i/o mem already in use.\n");
336                 return -EBUSY;
337         }
338 
339         mrst_rtc.irq = rtc_irq;
340         mrst_rtc.iomem = iomem;
341         mrst_rtc.dev = dev;
342         dev_set_drvdata(dev, &mrst_rtc);
343 
344         mrst_rtc.rtc = rtc_device_register(driver_name, dev,
345                                 &mrst_rtc_ops, THIS_MODULE);
346         if (IS_ERR(mrst_rtc.rtc)) {
347                 retval = PTR_ERR(mrst_rtc.rtc);
348                 goto cleanup0;
349         }
350 
351         rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
352 
353         spin_lock_irq(&rtc_lock);
354         mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
355         rtc_control = vrtc_cmos_read(RTC_CONTROL);
356         spin_unlock_irq(&rtc_lock);
357 
358         if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
359                 dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
360 
361         if (rtc_irq) {
362                 retval = request_irq(rtc_irq, mrst_rtc_irq,
363                                 0, dev_name(&mrst_rtc.rtc->dev),
364                                 mrst_rtc.rtc);
365                 if (retval < 0) {
366                         dev_dbg(dev, "IRQ %d is already in use, err %d\n",
367                                 rtc_irq, retval);
368                         goto cleanup1;
369                 }
370         }
371         dev_dbg(dev, "initialised\n");
372         return 0;
373 
374 cleanup1:
375         rtc_device_unregister(mrst_rtc.rtc);
376 cleanup0:
377         mrst_rtc.dev = NULL;
378         release_mem_region(iomem->start, resource_size(iomem));
379         dev_err(dev, "rtc-mrst: unable to initialise\n");
380         return retval;
381 }
382 
383 static void rtc_mrst_do_shutdown(void)
384 {
385         spin_lock_irq(&rtc_lock);
386         mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
387         spin_unlock_irq(&rtc_lock);
388 }
389 
390 static void rtc_mrst_do_remove(struct device *dev)
391 {
392         struct mrst_rtc *mrst = dev_get_drvdata(dev);
393         struct resource *iomem;
394 
395         rtc_mrst_do_shutdown();
396 
397         if (mrst->irq)
398                 free_irq(mrst->irq, mrst->rtc);
399 
400         rtc_device_unregister(mrst->rtc);
401         mrst->rtc = NULL;
402 
403         iomem = mrst->iomem;
404         release_mem_region(iomem->start, resource_size(iomem));
405         mrst->iomem = NULL;
406 
407         mrst->dev = NULL;
408 }
409 
410 #ifdef CONFIG_PM_SLEEP
411 static int mrst_suspend(struct device *dev)
412 {
413         struct mrst_rtc *mrst = dev_get_drvdata(dev);
414         unsigned char   tmp;
415 
416         /* Only the alarm might be a wakeup event source */
417         spin_lock_irq(&rtc_lock);
418         mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
419         if (tmp & (RTC_PIE | RTC_AIE)) {
420                 unsigned char   mask;
421 
422                 if (device_may_wakeup(dev))
423                         mask = RTC_IRQMASK & ~RTC_AIE;
424                 else
425                         mask = RTC_IRQMASK;
426                 tmp &= ~mask;
427                 vrtc_cmos_write(tmp, RTC_CONTROL);
428 
429                 mrst_checkintr(mrst, tmp);
430         }
431         spin_unlock_irq(&rtc_lock);
432 
433         if (tmp & RTC_AIE) {
434                 mrst->enabled_wake = 1;
435                 enable_irq_wake(mrst->irq);
436         }
437 
438         dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
439                         (tmp & RTC_AIE) ? ", alarm may wake" : "",
440                         tmp);
441 
442         return 0;
443 }
444 
445 /*
446  * We want RTC alarms to wake us from the deep power saving state
447  */
448 static inline int mrst_poweroff(struct device *dev)
449 {
450         return mrst_suspend(dev);
451 }
452 
453 static int mrst_resume(struct device *dev)
454 {
455         struct mrst_rtc *mrst = dev_get_drvdata(dev);
456         unsigned char tmp = mrst->suspend_ctrl;
457 
458         /* Re-enable any irqs previously active */
459         if (tmp & RTC_IRQMASK) {
460                 unsigned char   mask;
461 
462                 if (mrst->enabled_wake) {
463                         disable_irq_wake(mrst->irq);
464                         mrst->enabled_wake = 0;
465                 }
466 
467                 spin_lock_irq(&rtc_lock);
468                 do {
469                         vrtc_cmos_write(tmp, RTC_CONTROL);
470 
471                         mask = vrtc_cmos_read(RTC_INTR_FLAGS);
472                         mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
473                         if (!is_intr(mask))
474                                 break;
475 
476                         rtc_update_irq(mrst->rtc, 1, mask);
477                         tmp &= ~RTC_AIE;
478                 } while (mask & RTC_AIE);
479                 spin_unlock_irq(&rtc_lock);
480         }
481 
482         dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
483 
484         return 0;
485 }
486 
487 static SIMPLE_DEV_PM_OPS(mrst_pm_ops, mrst_suspend, mrst_resume);
488 #define MRST_PM_OPS (&mrst_pm_ops)
489 
490 #else
491 #define MRST_PM_OPS NULL
492 
493 static inline int mrst_poweroff(struct device *dev)
494 {
495         return -ENOSYS;
496 }
497 
498 #endif
499 
500 static int vrtc_mrst_platform_probe(struct platform_device *pdev)
501 {
502         return vrtc_mrst_do_probe(&pdev->dev,
503                         platform_get_resource(pdev, IORESOURCE_MEM, 0),
504                         platform_get_irq(pdev, 0));
505 }
506 
507 static int vrtc_mrst_platform_remove(struct platform_device *pdev)
508 {
509         rtc_mrst_do_remove(&pdev->dev);
510         return 0;
511 }
512 
513 static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
514 {
515         if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
516                 return;
517 
518         rtc_mrst_do_shutdown();
519 }
520 
521 MODULE_ALIAS("platform:vrtc_mrst");
522 
523 static struct platform_driver vrtc_mrst_platform_driver = {
524         .probe          = vrtc_mrst_platform_probe,
525         .remove         = vrtc_mrst_platform_remove,
526         .shutdown       = vrtc_mrst_platform_shutdown,
527         .driver = {
528                 .name   = driver_name,
529                 .pm     = MRST_PM_OPS,
530         }
531 };
532 
533 module_platform_driver(vrtc_mrst_platform_driver);
534 
535 MODULE_AUTHOR("Jacob Pan; Feng Tang");
536 MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
537 MODULE_LICENSE("GPL");
538 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us