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