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/module.h>
36 #include <linux/init.h>
37 #include <linux/sfi.h>
38
39 #include <asm-generic/rtc.h>
40 #include <asm/intel_scu_ipc.h>
41 #include <asm/mrst.h>
42 #include <asm/mrst-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
is_intr(u8 rtc_intr)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
vrtc_is_updating(void)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 1960 (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 1960 will
83 * make it consistent in leap year setting for both vrtc and low-level
84 * physical rtc devices.
85 */
mrst_read_time(struct device * dev,struct rtc_time * time)86 static int mrst_read_time(struct device *dev, struct rtc_time *time)
87 {
88 unsigned long flags;
89
90 if (vrtc_is_updating())
91 mdelay(20);
92
93 spin_lock_irqsave(&rtc_lock, flags);
94 time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
95 time->tm_min = vrtc_cmos_read(RTC_MINUTES);
96 time->tm_hour = vrtc_cmos_read(RTC_HOURS);
97 time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
98 time->tm_mon = vrtc_cmos_read(RTC_MONTH);
99 time->tm_year = vrtc_cmos_read(RTC_YEAR);
100 spin_unlock_irqrestore(&rtc_lock, flags);
101
102 /* Adjust for the 1960/1900 */
103 time->tm_year += 60;
104 time->tm_mon--;
105 return RTC_24H;
106 }
107
mrst_set_time(struct device * dev,struct rtc_time * time)108 static int mrst_set_time(struct device *dev, struct rtc_time *time)
109 {
110 int ret;
111 unsigned long flags;
112 unsigned char mon, day, hrs, min, sec;
113 unsigned int yrs;
114
115 yrs = time->tm_year;
116 mon = time->tm_mon + 1; /* tm_mon starts at zero */
117 day = time->tm_mday;
118 hrs = time->tm_hour;
119 min = time->tm_min;
120 sec = time->tm_sec;
121
122 if (yrs < 70 || yrs > 138)
123 return -EINVAL;
124 yrs -= 60;
125
126 spin_lock_irqsave(&rtc_lock, flags);
127
128 vrtc_cmos_write(yrs, RTC_YEAR);
129 vrtc_cmos_write(mon, RTC_MONTH);
130 vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
131 vrtc_cmos_write(hrs, RTC_HOURS);
132 vrtc_cmos_write(min, RTC_MINUTES);
133 vrtc_cmos_write(sec, RTC_SECONDS);
134
135 spin_unlock_irqrestore(&rtc_lock, flags);
136
137 ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
138 return ret;
139 }
140
mrst_read_alarm(struct device * dev,struct rtc_wkalrm * t)141 static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t)
142 {
143 struct mrst_rtc *mrst = dev_get_drvdata(dev);
144 unsigned char rtc_control;
145
146 if (mrst->irq <= 0)
147 return -EIO;
148
149 /* Basic alarms only support hour, minute, and seconds fields.
150 * Some also support day and month, for alarms up to a year in
151 * the future.
152 */
153 t->time.tm_mday = -1;
154 t->time.tm_mon = -1;
155 t->time.tm_year = -1;
156
157 /* vRTC only supports binary mode */
158 spin_lock_irq(&rtc_lock);
159 t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
160 t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
161 t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
162
163 rtc_control = vrtc_cmos_read(RTC_CONTROL);
164 spin_unlock_irq(&rtc_lock);
165
166 t->enabled = !!(rtc_control & RTC_AIE);
167 t->pending = 0;
168
169 return 0;
170 }
171
mrst_checkintr(struct mrst_rtc * mrst,unsigned char rtc_control)172 static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
173 {
174 unsigned char rtc_intr;
175
176 /*
177 * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
178 * allegedly some older rtcs need that to handle irqs properly
179 */
180 rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
181 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
182 if (is_intr(rtc_intr))
183 rtc_update_irq(mrst->rtc, 1, rtc_intr);
184 }
185
mrst_irq_enable(struct mrst_rtc * mrst,unsigned char mask)186 static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
187 {
188 unsigned char rtc_control;
189
190 /*
191 * Flush any pending IRQ status, notably for update irqs,
192 * before we enable new IRQs
193 */
194 rtc_control = vrtc_cmos_read(RTC_CONTROL);
195 mrst_checkintr(mrst, rtc_control);
196
197 rtc_control |= mask;
198 vrtc_cmos_write(rtc_control, RTC_CONTROL);
199
200 mrst_checkintr(mrst, rtc_control);
201 }
202
mrst_irq_disable(struct mrst_rtc * mrst,unsigned char mask)203 static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
204 {
205 unsigned char rtc_control;
206
207 rtc_control = vrtc_cmos_read(RTC_CONTROL);
208 rtc_control &= ~mask;
209 vrtc_cmos_write(rtc_control, RTC_CONTROL);
210 mrst_checkintr(mrst, rtc_control);
211 }
212
mrst_set_alarm(struct device * dev,struct rtc_wkalrm * t)213 static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t)
214 {
215 struct mrst_rtc *mrst = dev_get_drvdata(dev);
216 unsigned char hrs, min, sec;
217 int ret = 0;
218
219 if (!mrst->irq)
220 return -EIO;
221
222 hrs = t->time.tm_hour;
223 min = t->time.tm_min;
224 sec = t->time.tm_sec;
225
226 spin_lock_irq(&rtc_lock);
227 /* Next rtc irq must not be from previous alarm setting */
228 mrst_irq_disable(mrst, RTC_AIE);
229
230 /* Update alarm */
231 vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
232 vrtc_cmos_write(min, RTC_MINUTES_ALARM);
233 vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
234
235 spin_unlock_irq(&rtc_lock);
236
237 ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
238 if (ret)
239 return ret;
240
241 spin_lock_irq(&rtc_lock);
242 if (t->enabled)
243 mrst_irq_enable(mrst, RTC_AIE);
244
245 spin_unlock_irq(&rtc_lock);
246
247 return 0;
248 }
249
250 /* Currently, the vRTC doesn't support UIE ON/OFF */
mrst_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)251 static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
252 {
253 struct mrst_rtc *mrst = dev_get_drvdata(dev);
254 unsigned long flags;
255
256 spin_lock_irqsave(&rtc_lock, flags);
257 if (enabled)
258 mrst_irq_enable(mrst, RTC_AIE);
259 else
260 mrst_irq_disable(mrst, RTC_AIE);
261 spin_unlock_irqrestore(&rtc_lock, flags);
262 return 0;
263 }
264
265
266 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
267
mrst_procfs(struct device * dev,struct seq_file * seq)268 static int mrst_procfs(struct device *dev, struct seq_file *seq)
269 {
270 unsigned char rtc_control, valid;
271
272 spin_lock_irq(&rtc_lock);
273 rtc_control = vrtc_cmos_read(RTC_CONTROL);
274 valid = vrtc_cmos_read(RTC_VALID);
275 spin_unlock_irq(&rtc_lock);
276
277 return seq_printf(seq,
278 "periodic_IRQ\t: %s\n"
279 "alarm\t\t: %s\n"
280 "BCD\t\t: no\n"
281 "periodic_freq\t: daily (not adjustable)\n",
282 (rtc_control & RTC_PIE) ? "on" : "off",
283 (rtc_control & RTC_AIE) ? "on" : "off");
284 }
285
286 #else
287 #define mrst_procfs NULL
288 #endif
289
290 static const struct rtc_class_ops mrst_rtc_ops = {
291 .read_time = mrst_read_time,
292 .set_time = mrst_set_time,
293 .read_alarm = mrst_read_alarm,
294 .set_alarm = mrst_set_alarm,
295 .proc = mrst_procfs,
296 .alarm_irq_enable = mrst_rtc_alarm_irq_enable,
297 };
298
299 static struct mrst_rtc mrst_rtc;
300
301 /*
302 * When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
303 * Reg B, so no need for this driver to clear it
304 */
mrst_rtc_irq(int irq,void * p)305 static irqreturn_t mrst_rtc_irq(int irq, void *p)
306 {
307 u8 irqstat;
308
309 spin_lock(&rtc_lock);
310 /* This read will clear all IRQ flags inside Reg C */
311 irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
312 spin_unlock(&rtc_lock);
313
314 irqstat &= RTC_IRQMASK | RTC_IRQF;
315 if (is_intr(irqstat)) {
316 rtc_update_irq(p, 1, irqstat);
317 return IRQ_HANDLED;
318 }
319 return IRQ_NONE;
320 }
321
322 static int __devinit
vrtc_mrst_do_probe(struct device * dev,struct resource * iomem,int rtc_irq)323 vrtc_mrst_do_probe(struct device *dev, struct resource *iomem, int rtc_irq)
324 {
325 int retval = 0;
326 unsigned char rtc_control;
327
328 /* There can be only one ... */
329 if (mrst_rtc.dev)
330 return -EBUSY;
331
332 if (!iomem)
333 return -ENODEV;
334
335 iomem = request_mem_region(iomem->start,
336 iomem->end + 1 - iomem->start,
337 driver_name);
338 if (!iomem) {
339 dev_dbg(dev, "i/o mem already in use.\n");
340 return -EBUSY;
341 }
342
343 mrst_rtc.irq = rtc_irq;
344 mrst_rtc.iomem = iomem;
345 mrst_rtc.dev = dev;
346 dev_set_drvdata(dev, &mrst_rtc);
347
348 mrst_rtc.rtc = rtc_device_register(driver_name, dev,
349 &mrst_rtc_ops, THIS_MODULE);
350 if (IS_ERR(mrst_rtc.rtc)) {
351 retval = PTR_ERR(mrst_rtc.rtc);
352 goto cleanup0;
353 }
354
355 rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
356
357 spin_lock_irq(&rtc_lock);
358 mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
359 rtc_control = vrtc_cmos_read(RTC_CONTROL);
360 spin_unlock_irq(&rtc_lock);
361
362 if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
363 dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
364
365 if (rtc_irq) {
366 retval = request_irq(rtc_irq, mrst_rtc_irq,
367 IRQF_DISABLED, dev_name(&mrst_rtc.rtc->dev),
368 mrst_rtc.rtc);
369 if (retval < 0) {
370 dev_dbg(dev, "IRQ %d is already in use, err %d\n",
371 rtc_irq, retval);
372 goto cleanup1;
373 }
374 }
375 dev_dbg(dev, "initialised\n");
376 return 0;
377
378 cleanup1:
379 rtc_device_unregister(mrst_rtc.rtc);
380 cleanup0:
381 dev_set_drvdata(dev, NULL);
382 mrst_rtc.dev = NULL;
383 release_region(iomem->start, iomem->end + 1 - iomem->start);
384 dev_err(dev, "rtc-mrst: unable to initialise\n");
385 return retval;
386 }
387
rtc_mrst_do_shutdown(void)388 static void rtc_mrst_do_shutdown(void)
389 {
390 spin_lock_irq(&rtc_lock);
391 mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
392 spin_unlock_irq(&rtc_lock);
393 }
394
rtc_mrst_do_remove(struct device * dev)395 static void __devexit rtc_mrst_do_remove(struct device *dev)
396 {
397 struct mrst_rtc *mrst = dev_get_drvdata(dev);
398 struct resource *iomem;
399
400 rtc_mrst_do_shutdown();
401
402 if (mrst->irq)
403 free_irq(mrst->irq, mrst->rtc);
404
405 rtc_device_unregister(mrst->rtc);
406 mrst->rtc = NULL;
407
408 iomem = mrst->iomem;
409 release_region(iomem->start, iomem->end + 1 - iomem->start);
410 mrst->iomem = NULL;
411
412 mrst->dev = NULL;
413 dev_set_drvdata(dev, NULL);
414 }
415
416 #ifdef CONFIG_PM
mrst_suspend(struct device * dev,pm_message_t mesg)417 static int mrst_suspend(struct device *dev, pm_message_t mesg)
418 {
419 struct mrst_rtc *mrst = dev_get_drvdata(dev);
420 unsigned char tmp;
421
422 /* Only the alarm might be a wakeup event source */
423 spin_lock_irq(&rtc_lock);
424 mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
425 if (tmp & (RTC_PIE | RTC_AIE)) {
426 unsigned char mask;
427
428 if (device_may_wakeup(dev))
429 mask = RTC_IRQMASK & ~RTC_AIE;
430 else
431 mask = RTC_IRQMASK;
432 tmp &= ~mask;
433 vrtc_cmos_write(tmp, RTC_CONTROL);
434
435 mrst_checkintr(mrst, tmp);
436 }
437 spin_unlock_irq(&rtc_lock);
438
439 if (tmp & RTC_AIE) {
440 mrst->enabled_wake = 1;
441 enable_irq_wake(mrst->irq);
442 }
443
444 dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
445 (tmp & RTC_AIE) ? ", alarm may wake" : "",
446 tmp);
447
448 return 0;
449 }
450
451 /*
452 * We want RTC alarms to wake us from the deep power saving state
453 */
mrst_poweroff(struct device * dev)454 static inline int mrst_poweroff(struct device *dev)
455 {
456 return mrst_suspend(dev, PMSG_HIBERNATE);
457 }
458
mrst_resume(struct device * dev)459 static int mrst_resume(struct device *dev)
460 {
461 struct mrst_rtc *mrst = dev_get_drvdata(dev);
462 unsigned char tmp = mrst->suspend_ctrl;
463
464 /* Re-enable any irqs previously active */
465 if (tmp & RTC_IRQMASK) {
466 unsigned char mask;
467
468 if (mrst->enabled_wake) {
469 disable_irq_wake(mrst->irq);
470 mrst->enabled_wake = 0;
471 }
472
473 spin_lock_irq(&rtc_lock);
474 do {
475 vrtc_cmos_write(tmp, RTC_CONTROL);
476
477 mask = vrtc_cmos_read(RTC_INTR_FLAGS);
478 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
479 if (!is_intr(mask))
480 break;
481
482 rtc_update_irq(mrst->rtc, 1, mask);
483 tmp &= ~RTC_AIE;
484 } while (mask & RTC_AIE);
485 spin_unlock_irq(&rtc_lock);
486 }
487
488 dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
489
490 return 0;
491 }
492
493 #else
494 #define mrst_suspend NULL
495 #define mrst_resume NULL
496
mrst_poweroff(struct device * dev)497 static inline int mrst_poweroff(struct device *dev)
498 {
499 return -ENOSYS;
500 }
501
502 #endif
503
vrtc_mrst_platform_probe(struct platform_device * pdev)504 static int __devinit vrtc_mrst_platform_probe(struct platform_device *pdev)
505 {
506 return vrtc_mrst_do_probe(&pdev->dev,
507 platform_get_resource(pdev, IORESOURCE_MEM, 0),
508 platform_get_irq(pdev, 0));
509 }
510
vrtc_mrst_platform_remove(struct platform_device * pdev)511 static int __devexit vrtc_mrst_platform_remove(struct platform_device *pdev)
512 {
513 rtc_mrst_do_remove(&pdev->dev);
514 return 0;
515 }
516
vrtc_mrst_platform_shutdown(struct platform_device * pdev)517 static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
518 {
519 if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
520 return;
521
522 rtc_mrst_do_shutdown();
523 }
524
525 MODULE_ALIAS("platform:vrtc_mrst");
526
527 static struct platform_driver vrtc_mrst_platform_driver = {
528 .probe = vrtc_mrst_platform_probe,
529 .remove = __devexit_p(vrtc_mrst_platform_remove),
530 .shutdown = vrtc_mrst_platform_shutdown,
531 .driver = {
532 .name = (char *) driver_name,
533 .suspend = mrst_suspend,
534 .resume = mrst_resume,
535 }
536 };
537
vrtc_mrst_init(void)538 static int __init vrtc_mrst_init(void)
539 {
540 return platform_driver_register(&vrtc_mrst_platform_driver);
541 }
542
vrtc_mrst_exit(void)543 static void __exit vrtc_mrst_exit(void)
544 {
545 platform_driver_unregister(&vrtc_mrst_platform_driver);
546 }
547
548 module_init(vrtc_mrst_init);
549 module_exit(vrtc_mrst_exit);
550
551 MODULE_AUTHOR("Jacob Pan; Feng Tang");
552 MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
553 MODULE_LICENSE("GPL");
554