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
 44struct 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
 54static const char driver_name[] = "rtc_mrst";
 55
 56#define	RTC_IRQMASK	(RTC_PF | RTC_AF)
 57
 58static 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
 65static 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 */
 86static 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
108static 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
141static 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
172static 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
186static 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
203static 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
213static 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 */
251static 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
268static 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
290static 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
299static 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 */
305static 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
322static int __devinit
323vrtc_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, resource_size(iomem),
336				   driver_name);
337	if (!iomem) {
338		dev_dbg(dev, "i/o mem already in use.\n");
339		return -EBUSY;
340	}
341
342	mrst_rtc.irq = rtc_irq;
343	mrst_rtc.iomem = iomem;
344	mrst_rtc.dev = dev;
345	dev_set_drvdata(dev, &mrst_rtc);
346
347	mrst_rtc.rtc = rtc_device_register(driver_name, dev,
348				&mrst_rtc_ops, THIS_MODULE);
349	if (IS_ERR(mrst_rtc.rtc)) {
350		retval = PTR_ERR(mrst_rtc.rtc);
351		goto cleanup0;
352	}
353
354	rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
355
356	spin_lock_irq(&rtc_lock);
357	mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
358	rtc_control = vrtc_cmos_read(RTC_CONTROL);
359	spin_unlock_irq(&rtc_lock);
360
361	if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
362		dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
363
364	if (rtc_irq) {
365		retval = request_irq(rtc_irq, mrst_rtc_irq,
366				IRQF_DISABLED, dev_name(&mrst_rtc.rtc->dev),
367				mrst_rtc.rtc);
368		if (retval < 0) {
369			dev_dbg(dev, "IRQ %d is already in use, err %d\n",
370				rtc_irq, retval);
371			goto cleanup1;
372		}
373	}
374	dev_dbg(dev, "initialised\n");
375	return 0;
376
377cleanup1:
378	rtc_device_unregister(mrst_rtc.rtc);
379cleanup0:
380	dev_set_drvdata(dev, NULL);
381	mrst_rtc.dev = NULL;
382	release_mem_region(iomem->start, resource_size(iomem));
383	dev_err(dev, "rtc-mrst: unable to initialise\n");
384	return retval;
385}
386
387static void rtc_mrst_do_shutdown(void)
388{
389	spin_lock_irq(&rtc_lock);
390	mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
391	spin_unlock_irq(&rtc_lock);
392}
393
394static void __devexit rtc_mrst_do_remove(struct device *dev)
395{
396	struct mrst_rtc	*mrst = dev_get_drvdata(dev);
397	struct resource *iomem;
398
399	rtc_mrst_do_shutdown();
400
401	if (mrst->irq)
402		free_irq(mrst->irq, mrst->rtc);
403
404	rtc_device_unregister(mrst->rtc);
405	mrst->rtc = NULL;
406
407	iomem = mrst->iomem;
408	release_mem_region(iomem->start, resource_size(iomem));
409	mrst->iomem = NULL;
410
411	mrst->dev = NULL;
412	dev_set_drvdata(dev, NULL);
413}
414
415#ifdef	CONFIG_PM
416static int mrst_suspend(struct device *dev, pm_message_t mesg)
417{
418	struct mrst_rtc	*mrst = dev_get_drvdata(dev);
419	unsigned char	tmp;
420
421	/* Only the alarm might be a wakeup event source */
422	spin_lock_irq(&rtc_lock);
423	mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
424	if (tmp & (RTC_PIE | RTC_AIE)) {
425		unsigned char	mask;
426
427		if (device_may_wakeup(dev))
428			mask = RTC_IRQMASK & ~RTC_AIE;
429		else
430			mask = RTC_IRQMASK;
431		tmp &= ~mask;
432		vrtc_cmos_write(tmp, RTC_CONTROL);
433
434		mrst_checkintr(mrst, tmp);
435	}
436	spin_unlock_irq(&rtc_lock);
437
438	if (tmp & RTC_AIE) {
439		mrst->enabled_wake = 1;
440		enable_irq_wake(mrst->irq);
441	}
442
443	dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
444			(tmp & RTC_AIE) ? ", alarm may wake" : "",
445			tmp);
446
447	return 0;
448}
449
450/*
451 * We want RTC alarms to wake us from the deep power saving state
452 */
453static inline int mrst_poweroff(struct device *dev)
454{
455	return mrst_suspend(dev, PMSG_HIBERNATE);
456}
457
458static int mrst_resume(struct device *dev)
459{
460	struct mrst_rtc	*mrst = dev_get_drvdata(dev);
461	unsigned char tmp = mrst->suspend_ctrl;
462
463	/* Re-enable any irqs previously active */
464	if (tmp & RTC_IRQMASK) {
465		unsigned char	mask;
466
467		if (mrst->enabled_wake) {
468			disable_irq_wake(mrst->irq);
469			mrst->enabled_wake = 0;
470		}
471
472		spin_lock_irq(&rtc_lock);
473		do {
474			vrtc_cmos_write(tmp, RTC_CONTROL);
475
476			mask = vrtc_cmos_read(RTC_INTR_FLAGS);
477			mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
478			if (!is_intr(mask))
479				break;
480
481			rtc_update_irq(mrst->rtc, 1, mask);
482			tmp &= ~RTC_AIE;
483		} while (mask & RTC_AIE);
484		spin_unlock_irq(&rtc_lock);
485	}
486
487	dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
488
489	return 0;
490}
491
492#else
493#define	mrst_suspend	NULL
494#define	mrst_resume	NULL
495
496static inline int mrst_poweroff(struct device *dev)
497{
498	return -ENOSYS;
499}
500
501#endif
502
503static int __devinit vrtc_mrst_platform_probe(struct platform_device *pdev)
504{
505	return vrtc_mrst_do_probe(&pdev->dev,
506			platform_get_resource(pdev, IORESOURCE_MEM, 0),
507			platform_get_irq(pdev, 0));
508}
509
510static int __devexit vrtc_mrst_platform_remove(struct platform_device *pdev)
511{
512	rtc_mrst_do_remove(&pdev->dev);
513	return 0;
514}
515
516static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
517{
518	if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
519		return;
520
521	rtc_mrst_do_shutdown();
522}
523
524MODULE_ALIAS("platform:vrtc_mrst");
525
526static struct platform_driver vrtc_mrst_platform_driver = {
527	.probe		= vrtc_mrst_platform_probe,
528	.remove		= __devexit_p(vrtc_mrst_platform_remove),
529	.shutdown	= vrtc_mrst_platform_shutdown,
530	.driver = {
531		.name		= (char *) driver_name,
532		.suspend	= mrst_suspend,
533		.resume		= mrst_resume,
534	}
535};
536
537static int __init vrtc_mrst_init(void)
538{
539	return platform_driver_register(&vrtc_mrst_platform_driver);
540}
541
542static void __exit vrtc_mrst_exit(void)
543{
544	platform_driver_unregister(&vrtc_mrst_platform_driver);
545}
546
547module_init(vrtc_mrst_init);
548module_exit(vrtc_mrst_exit);
549
550MODULE_AUTHOR("Jacob Pan; Feng Tang");
551MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
552MODULE_LICENSE("GPL");