1/*
2 * EFI Time Services Driver for Linux
3 *
4 * Copyright (C) 1999 Hewlett-Packard Co
5 * Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
6 *
7 * Based on skeleton from the drivers/char/rtc.c driver by P. Gortmaker
8 *
9 * This code provides an architected & portable interface to the real time
10 * clock by using EFI instead of direct bit fiddling. The functionalities are
11 * quite different from the rtc.c driver. The only way to talk to the device
12 * is by using ioctl(). There is a /proc interface which provides the raw
13 * information.
14 *
15 * Please note that we have kept the API as close as possible to the
16 * legacy RTC. The standard /sbin/hwclock program should work normally
17 * when used to get/set the time.
18 *
19 * NOTES:
20 *	- Locking is required for safe execution of EFI calls with regards
21 *	  to interrupts and SMP.
22 *
23 * TODO (December 1999):
24 * 	- provide the API to set/get the WakeUp Alarm (different from the
25 *	  rtc.c alarm).
26 *	- SMP testing
27 * 	- Add module support
28 */
29
30#include <linux/types.h>
31#include <linux/errno.h>
32#include <linux/miscdevice.h>
33#include <linux/module.h>
34#include <linux/init.h>
35#include <linux/rtc.h>
36#include <linux/proc_fs.h>
37#include <linux/efi.h>
38#include <linux/uaccess.h>
39
40
41#define EFI_RTC_VERSION		"0.4"
42
43#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
44/*
45 * EFI Epoch is 1/1/1998
46 */
47#define EFI_RTC_EPOCH		1998
48
49static DEFINE_SPINLOCK(efi_rtc_lock);
50
51static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
52							unsigned long arg);
53
54#define is_leap(year) \
55          ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
56
57static const unsigned short int __mon_yday[2][13] =
58{
59	/* Normal years.  */
60	{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
61	/* Leap years.  */
62	{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
63};
64
65/*
66 * returns day of the year [0-365]
67 */
68static inline int
69compute_yday(efi_time_t *eft)
70{
71	/* efi_time_t.month is in the [1-12] so, we need -1 */
72	return  __mon_yday[is_leap(eft->year)][eft->month-1]+ eft->day -1;
73}
74/*
75 * returns day of the week [0-6] 0=Sunday
76 *
77 * Don't try to provide a year that's before 1998, please !
78 */
79static int
80compute_wday(efi_time_t *eft)
81{
82	int y;
83	int ndays = 0;
84
85	if ( eft->year < 1998 ) {
86		printk(KERN_ERR "efirtc: EFI year < 1998, invalid date\n");
87		return -1;
88	}
89
90	for(y=EFI_RTC_EPOCH; y < eft->year; y++ ) {
91		ndays += 365 + (is_leap(y) ? 1 : 0);
92	}
93	ndays += compute_yday(eft);
94
95	/*
96	 * 4=1/1/1998 was a Thursday
97	 */
98	return (ndays + 4) % 7;
99}
100
101static void
102convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)
103{
104
105	eft->year	= wtime->tm_year + 1900;
106	eft->month	= wtime->tm_mon + 1;
107	eft->day	= wtime->tm_mday;
108	eft->hour	= wtime->tm_hour;
109	eft->minute	= wtime->tm_min;
110	eft->second 	= wtime->tm_sec;
111	eft->nanosecond = 0;
112	eft->daylight	= wtime->tm_isdst ? EFI_ISDST: 0;
113	eft->timezone	= EFI_UNSPECIFIED_TIMEZONE;
114}
115
116static void
117convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
118{
119	memset(wtime, 0, sizeof(*wtime));
120	wtime->tm_sec  = eft->second;
121	wtime->tm_min  = eft->minute;
122	wtime->tm_hour = eft->hour;
123	wtime->tm_mday = eft->day;
124	wtime->tm_mon  = eft->month - 1;
125	wtime->tm_year = eft->year - 1900;
126
127	/* day of the week [0-6], Sunday=0 */
128	wtime->tm_wday = compute_wday(eft);
129
130	/* day in the year [1-365]*/
131	wtime->tm_yday = compute_yday(eft);
132
133
134	switch (eft->daylight & EFI_ISDST) {
135		case EFI_ISDST:
136			wtime->tm_isdst = 1;
137			break;
138		case EFI_TIME_ADJUST_DAYLIGHT:
139			wtime->tm_isdst = 0;
140			break;
141		default:
142			wtime->tm_isdst = -1;
143	}
144}
145
146static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
147							unsigned long arg)
148{
149
150	efi_status_t	status;
151	unsigned long	flags;
152	efi_time_t	eft;
153	efi_time_cap_t	cap;
154	struct rtc_time	wtime;
155	struct rtc_wkalrm __user *ewp;
156	unsigned char	enabled, pending;
157
158	switch (cmd) {
159		case RTC_UIE_ON:
160		case RTC_UIE_OFF:
161		case RTC_PIE_ON:
162		case RTC_PIE_OFF:
163		case RTC_AIE_ON:
164		case RTC_AIE_OFF:
165		case RTC_ALM_SET:
166		case RTC_ALM_READ:
167		case RTC_IRQP_READ:
168		case RTC_IRQP_SET:
169		case RTC_EPOCH_READ:
170		case RTC_EPOCH_SET:
171			return -EINVAL;
172
173		case RTC_RD_TIME:
174			spin_lock_irqsave(&efi_rtc_lock, flags);
175
176			status = efi.get_time(&eft, &cap);
177
178			spin_unlock_irqrestore(&efi_rtc_lock,flags);
179
180			if (status != EFI_SUCCESS) {
181				/* should never happen */
182				printk(KERN_ERR "efitime: can't read time\n");
183				return -EINVAL;
184			}
185
186			convert_from_efi_time(&eft, &wtime);
187
188 			return copy_to_user((void __user *)arg, &wtime,
189					    sizeof (struct rtc_time)) ? - EFAULT : 0;
190
191		case RTC_SET_TIME:
192
193			if (!capable(CAP_SYS_TIME)) return -EACCES;
194
195			if (copy_from_user(&wtime, (struct rtc_time __user *)arg,
196					   sizeof(struct rtc_time)) )
197				return -EFAULT;
198
199			convert_to_efi_time(&wtime, &eft);
200
201			spin_lock_irqsave(&efi_rtc_lock, flags);
202
203			status = efi.set_time(&eft);
204
205			spin_unlock_irqrestore(&efi_rtc_lock,flags);
206
207			return status == EFI_SUCCESS ? 0 : -EINVAL;
208
209		case RTC_WKALM_SET:
210
211			if (!capable(CAP_SYS_TIME)) return -EACCES;
212
213			ewp = (struct rtc_wkalrm __user *)arg;
214
215			if (  get_user(enabled, &ewp->enabled)
216			   || copy_from_user(&wtime, &ewp->time, sizeof(struct rtc_time)) )
217				return -EFAULT;
218
219			convert_to_efi_time(&wtime, &eft);
220
221			spin_lock_irqsave(&efi_rtc_lock, flags);
222			/*
223			 * XXX Fixme:
224			 * As of EFI 0.92 with the firmware I have on my
225			 * machine this call does not seem to work quite
226			 * right
227			 */
228			status = efi.set_wakeup_time((efi_bool_t)enabled, &eft);
229
230			spin_unlock_irqrestore(&efi_rtc_lock,flags);
231
232			return status == EFI_SUCCESS ? 0 : -EINVAL;
233
234		case RTC_WKALM_RD:
235
236			spin_lock_irqsave(&efi_rtc_lock, flags);
237
238			status = efi.get_wakeup_time((efi_bool_t *)&enabled, (efi_bool_t *)&pending, &eft);
239
240			spin_unlock_irqrestore(&efi_rtc_lock,flags);
241
242			if (status != EFI_SUCCESS) return -EINVAL;
243
244			ewp = (struct rtc_wkalrm __user *)arg;
245
246			if (  put_user(enabled, &ewp->enabled)
247			   || put_user(pending, &ewp->pending)) return -EFAULT;
248
249			convert_from_efi_time(&eft, &wtime);
250
251			return copy_to_user(&ewp->time, &wtime,
252					    sizeof(struct rtc_time)) ? -EFAULT : 0;
253	}
254	return -ENOTTY;
255}
256
257/*
258 *	We enforce only one user at a time here with the open/close.
259 *	Also clear the previous interrupt data on an open, and clean
260 *	up things on a close.
261 */
262
263static int efi_rtc_open(struct inode *inode, struct file *file)
264{
265	/*
266	 * nothing special to do here
267	 * We do accept multiple open files at the same time as we
268	 * synchronize on the per call operation.
269	 */
270	return 0;
271}
272
273static int efi_rtc_close(struct inode *inode, struct file *file)
274{
275	return 0;
276}
277
278/*
279 *	The various file operations we support.
280 */
281
282static const struct file_operations efi_rtc_fops = {
283	.owner		= THIS_MODULE,
284	.unlocked_ioctl	= efi_rtc_ioctl,
285	.open		= efi_rtc_open,
286	.release	= efi_rtc_close,
287	.llseek		= no_llseek,
288};
289
290static struct miscdevice efi_rtc_dev= {
291	EFI_RTC_MINOR,
292	"efirtc",
293	&efi_rtc_fops
294};
295
296/*
297 *	We export RAW EFI information to /proc/driver/efirtc
298 */
299static int
300efi_rtc_get_status(char *buf)
301{
302	efi_time_t 	eft, alm;
303	efi_time_cap_t	cap;
304	char		*p = buf;
305	efi_bool_t	enabled, pending;
306	unsigned long	flags;
307
308	memset(&eft, 0, sizeof(eft));
309	memset(&alm, 0, sizeof(alm));
310	memset(&cap, 0, sizeof(cap));
311
312	spin_lock_irqsave(&efi_rtc_lock, flags);
313
314	efi.get_time(&eft, &cap);
315	efi.get_wakeup_time(&enabled, &pending, &alm);
316
317	spin_unlock_irqrestore(&efi_rtc_lock,flags);
318
319	p += sprintf(p,
320		     "Time           : %u:%u:%u.%09u\n"
321		     "Date           : %u-%u-%u\n"
322		     "Daylight       : %u\n",
323		     eft.hour, eft.minute, eft.second, eft.nanosecond,
324		     eft.year, eft.month, eft.day,
325		     eft.daylight);
326
327	if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
328		p += sprintf(p, "Timezone       : unspecified\n");
329	else
330		/* XXX fixme: convert to string? */
331		p += sprintf(p, "Timezone       : %u\n", eft.timezone);
332
333
334	p += sprintf(p,
335		     "Alarm Time     : %u:%u:%u.%09u\n"
336		     "Alarm Date     : %u-%u-%u\n"
337		     "Alarm Daylight : %u\n"
338		     "Enabled        : %s\n"
339		     "Pending        : %s\n",
340		     alm.hour, alm.minute, alm.second, alm.nanosecond,
341		     alm.year, alm.month, alm.day,
342		     alm.daylight,
343		     enabled == 1 ? "yes" : "no",
344		     pending == 1 ? "yes" : "no");
345
346	if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
347		p += sprintf(p, "Timezone       : unspecified\n");
348	else
349		/* XXX fixme: convert to string? */
350		p += sprintf(p, "Timezone       : %u\n", alm.timezone);
351
352	/*
353	 * now prints the capabilities
354	 */
355	p += sprintf(p,
356		     "Resolution     : %u\n"
357		     "Accuracy       : %u\n"
358		     "SetstoZero     : %u\n",
359		      cap.resolution, cap.accuracy, cap.sets_to_zero);
360
361	return  p - buf;
362}
363
364static int
365efi_rtc_read_proc(char *page, char **start, off_t off,
366                                 int count, int *eof, void *data)
367{
368        int len = efi_rtc_get_status(page);
369        if (len <= off+count) *eof = 1;
370        *start = page + off;
371        len -= off;
372        if (len>count) len = count;
373        if (len<0) len = 0;
374        return len;
375}
376
377static int __init
378efi_rtc_init(void)
379{
380	int ret;
381	struct proc_dir_entry *dir;
382
383	printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);
384
385	ret = misc_register(&efi_rtc_dev);
386	if (ret) {
387		printk(KERN_ERR "efirtc: can't misc_register on minor=%d\n",
388				EFI_RTC_MINOR);
389		return ret;
390	}
391
392	dir = create_proc_read_entry ("driver/efirtc", 0, NULL,
393			              efi_rtc_read_proc, NULL);
394	if (dir == NULL) {
395		printk(KERN_ERR "efirtc: can't create /proc/driver/efirtc.\n");
396		misc_deregister(&efi_rtc_dev);
397		return -1;
398	}
399	return 0;
400}
401
402static void __exit
403efi_rtc_exit(void)
404{
405	/* not yet used */
406}
407
408module_init(efi_rtc_init);
409module_exit(efi_rtc_exit);
410
411MODULE_LICENSE("GPL");
412