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
31 #include <linux/smp_lock.h>
32 #include <linux/types.h>
33 #include <linux/errno.h>
34 #include <linux/miscdevice.h>
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/rtc.h>
38 #include <linux/proc_fs.h>
39 #include <linux/efi.h>
40 #include <linux/uaccess.h>
41
42 #include <asm/system.h>
43
44 #define EFI_RTC_VERSION "0.4"
45
46 #define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
47 /*
48 * EFI Epoch is 1/1/1998
49 */
50 #define EFI_RTC_EPOCH 1998
51
52 static DEFINE_SPINLOCK(efi_rtc_lock);
53
54 static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
55 unsigned long arg);
56
57 #define is_leap(year) \
58 ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
59
60 static const unsigned short int __mon_yday[2][13] =
61 {
62 /* Normal years. */
63 { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
64 /* Leap years. */
65 { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
66 };
67
68 /*
69 * returns day of the year [0-365]
70 */
71 static inline int
72 compute_yday(efi_time_t *eft)
73 {
74 /* efi_time_t.month is in the [1-12] so, we need -1 */
75 return __mon_yday[is_leap(eft->year)][eft->month-1]+ eft->day -1;
76 }
77 /*
78 * returns day of the week [0-6] 0=Sunday
79 *
80 * Don't try to provide a year that's before 1998, please !
81 */
82 static int
83 compute_wday(efi_time_t *eft)
84 {
85 int y;
86 int ndays = 0;
87
88 if ( eft->year < 1998 ) {
89 printk(KERN_ERR "efirtc: EFI year < 1998, invalid date\n");
90 return -1;
91 }
92
93 for(y=EFI_RTC_EPOCH; y < eft->year; y++ ) {
94 ndays += 365 + (is_leap(y) ? 1 : 0);
95 }
96 ndays += compute_yday(eft);
97
98 /*
99 * 4=1/1/1998 was a Thursday
100 */
101 return (ndays + 4) % 7;
102 }
103
104 static void
105 convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)
106 {
107
108 eft->year = wtime->tm_year + 1900;
109 eft->month = wtime->tm_mon + 1;
110 eft->day = wtime->tm_mday;
111 eft->hour = wtime->tm_hour;
112 eft->minute = wtime->tm_min;
113 eft->second = wtime->tm_sec;
114 eft->nanosecond = 0;
115 eft->daylight = wtime->tm_isdst ? EFI_ISDST: 0;
116 eft->timezone = EFI_UNSPECIFIED_TIMEZONE;
117 }
118
119 static void
120 convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
121 {
122 memset(wtime, 0, sizeof(*wtime));
123 wtime->tm_sec = eft->second;
124 wtime->tm_min = eft->minute;
125 wtime->tm_hour = eft->hour;
126 wtime->tm_mday = eft->day;
127 wtime->tm_mon = eft->month - 1;
128 wtime->tm_year = eft->year - 1900;
129
130 /* day of the week [0-6], Sunday=0 */
131 wtime->tm_wday = compute_wday(eft);
132
133 /* day in the year [1-365]*/
134 wtime->tm_yday = compute_yday(eft);
135
136
137 switch (eft->daylight & EFI_ISDST) {
138 case EFI_ISDST:
139 wtime->tm_isdst = 1;
140 break;
141 case EFI_TIME_ADJUST_DAYLIGHT:
142 wtime->tm_isdst = 0;
143 break;
144 default:
145 wtime->tm_isdst = -1;
146 }
147 }
148
149 static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
150 unsigned long arg)
151 {
152
153 efi_status_t status;
154 unsigned long flags;
155 efi_time_t eft;
156 efi_time_cap_t cap;
157 struct rtc_time wtime;
158 struct rtc_wkalrm __user *ewp;
159 unsigned char enabled, pending;
160
161 switch (cmd) {
162 case RTC_UIE_ON:
163 case RTC_UIE_OFF:
164 case RTC_PIE_ON:
165 case RTC_PIE_OFF:
166 case RTC_AIE_ON:
167 case RTC_AIE_OFF:
168 case RTC_ALM_SET:
169 case RTC_ALM_READ:
170 case RTC_IRQP_READ:
171 case RTC_IRQP_SET:
172 case RTC_EPOCH_READ:
173 case RTC_EPOCH_SET:
174 return -EINVAL;
175
176 case RTC_RD_TIME:
177 lock_kernel();
178 spin_lock_irqsave(&efi_rtc_lock, flags);
179
180 status = efi.get_time(&eft, &cap);
181
182 spin_unlock_irqrestore(&efi_rtc_lock,flags);
183 unlock_kernel();
184 if (status != EFI_SUCCESS) {
185 /* should never happen */
186 printk(KERN_ERR "efitime: can't read time\n");
187 return -EINVAL;
188 }
189
190 convert_from_efi_time(&eft, &wtime);
191
192 return copy_to_user((void __user *)arg, &wtime,
193 sizeof (struct rtc_time)) ? - EFAULT : 0;
194
195 case RTC_SET_TIME:
196
197 if (!capable(CAP_SYS_TIME)) return -EACCES;
198
199 if (copy_from_user(&wtime, (struct rtc_time __user *)arg,
200 sizeof(struct rtc_time)) )
201 return -EFAULT;
202
203 convert_to_efi_time(&wtime, &eft);
204
205 lock_kernel();
206 spin_lock_irqsave(&efi_rtc_lock, flags);
207
208 status = efi.set_time(&eft);
209
210 spin_unlock_irqrestore(&efi_rtc_lock,flags);
211 unlock_kernel();
212
213 return status == EFI_SUCCESS ? 0 : -EINVAL;
214
215 case RTC_WKALM_SET:
216
217 if (!capable(CAP_SYS_TIME)) return -EACCES;
218
219 ewp = (struct rtc_wkalrm __user *)arg;
220
221 if ( get_user(enabled, &ewp->enabled)
222 || copy_from_user(&wtime, &ewp->time, sizeof(struct rtc_time)) )
223 return -EFAULT;
224
225 convert_to_efi_time(&wtime, &eft);
226
227 lock_kernel();
228 spin_lock_irqsave(&efi_rtc_lock, flags);
229 /*
230 * XXX Fixme:
231 * As of EFI 0.92 with the firmware I have on my
232 * machine this call does not seem to work quite
233 * right
234 */
235 status = efi.set_wakeup_time((efi_bool_t)enabled, &eft);
236
237 spin_unlock_irqrestore(&efi_rtc_lock,flags);
238 unlock_kernel();
239
240 return status == EFI_SUCCESS ? 0 : -EINVAL;
241
242 case RTC_WKALM_RD:
243
244 lock_kernel();
245 spin_lock_irqsave(&efi_rtc_lock, flags);
246
247 status = efi.get_wakeup_time((efi_bool_t *)&enabled, (efi_bool_t *)&pending, &eft);
248
249 spin_unlock_irqrestore(&efi_rtc_lock,flags);
250 unlock_kernel();
251
252 if (status != EFI_SUCCESS) return -EINVAL;
253
254 ewp = (struct rtc_wkalrm __user *)arg;
255
256 if ( put_user(enabled, &ewp->enabled)
257 || put_user(pending, &ewp->pending)) return -EFAULT;
258
259 convert_from_efi_time(&eft, &wtime);
260
261 return copy_to_user(&ewp->time, &wtime,
262 sizeof(struct rtc_time)) ? -EFAULT : 0;
263 }
264 return -ENOTTY;
265 }
266
267 /*
268 * We enforce only one user at a time here with the open/close.
269 * Also clear the previous interrupt data on an open, and clean
270 * up things on a close.
271 */
272
273 static int efi_rtc_open(struct inode *inode, struct file *file)
274 {
275 /*
276 * nothing special to do here
277 * We do accept multiple open files at the same time as we
278 * synchronize on the per call operation.
279 */
280 cycle_kernel_lock();
281 return 0;
282 }
283
284 static int efi_rtc_close(struct inode *inode, struct file *file)
285 {
286 return 0;
287 }
288
289 /*
290 * The various file operations we support.
291 */
292
293 static const struct file_operations efi_rtc_fops = {
294 .owner = THIS_MODULE,
295 .unlocked_ioctl = efi_rtc_ioctl,
296 .open = efi_rtc_open,
297 .release = efi_rtc_close,
298 };
299
300 static struct miscdevice efi_rtc_dev= {
301 EFI_RTC_MINOR,
302 "efirtc",
303 &efi_rtc_fops
304 };
305
306 /*
307 * We export RAW EFI information to /proc/driver/efirtc
308 */
309 static int
310 efi_rtc_get_status(char *buf)
311 {
312 efi_time_t eft, alm;
313 efi_time_cap_t cap;
314 char *p = buf;
315 efi_bool_t enabled, pending;
316 unsigned long flags;
317
318 memset(&eft, 0, sizeof(eft));
319 memset(&alm, 0, sizeof(alm));
320 memset(&cap, 0, sizeof(cap));
321
322 spin_lock_irqsave(&efi_rtc_lock, flags);
323
324 efi.get_time(&eft, &cap);
325 efi.get_wakeup_time(&enabled, &pending, &alm);
326
327 spin_unlock_irqrestore(&efi_rtc_lock,flags);
328
329 p += sprintf(p,
330 "Time : %u:%u:%u.%09u\n"
331 "Date : %u-%u-%u\n"
332 "Daylight : %u\n",
333 eft.hour, eft.minute, eft.second, eft.nanosecond,
334 eft.year, eft.month, eft.day,
335 eft.daylight);
336
337 if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
338 p += sprintf(p, "Timezone : unspecified\n");
339 else
340 /* XXX fixme: convert to string? */
341 p += sprintf(p, "Timezone : %u\n", eft.timezone);
342
343
344 p += sprintf(p,
345 "Alarm Time : %u:%u:%u.%09u\n"
346 "Alarm Date : %u-%u-%u\n"
347 "Alarm Daylight : %u\n"
348 "Enabled : %s\n"
349 "Pending : %s\n",
350 alm.hour, alm.minute, alm.second, alm.nanosecond,
351 alm.year, alm.month, alm.day,
352 alm.daylight,
353 enabled == 1 ? "yes" : "no",
354 pending == 1 ? "yes" : "no");
355
356 if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
357 p += sprintf(p, "Timezone : unspecified\n");
358 else
359 /* XXX fixme: convert to string? */
360 p += sprintf(p, "Timezone : %u\n", alm.timezone);
361
362 /*
363 * now prints the capabilities
364 */
365 p += sprintf(p,
366 "Resolution : %u\n"
367 "Accuracy : %u\n"
368 "SetstoZero : %u\n",
369 cap.resolution, cap.accuracy, cap.sets_to_zero);
370
371 return p - buf;
372 }
373
374 static int
375 efi_rtc_read_proc(char *page, char **start, off_t off,
376 int count, int *eof, void *data)
377 {
378 int len = efi_rtc_get_status(page);
379 if (len <= off+count) *eof = 1;
380 *start = page + off;
381 len -= off;
382 if (len>count) len = count;
383 if (len<0) len = 0;
384 return len;
385 }
386
387 static int __init
388 efi_rtc_init(void)
389 {
390 int ret;
391 struct proc_dir_entry *dir;
392
393 printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);
394
395 ret = misc_register(&efi_rtc_dev);
396 if (ret) {
397 printk(KERN_ERR "efirtc: can't misc_register on minor=%d\n",
398 EFI_RTC_MINOR);
399 return ret;
400 }
401
402 dir = create_proc_read_entry ("driver/efirtc", 0, NULL,
403 efi_rtc_read_proc, NULL);
404 if (dir == NULL) {
405 printk(KERN_ERR "efirtc: can't create /proc/driver/efirtc.\n");
406 misc_deregister(&efi_rtc_dev);
407 return -1;
408 }
409 return 0;
410 }
411
412 static void __exit
413 efi_rtc_exit(void)
414 {
415 /* not yet used */
416 }
417
418 module_init(efi_rtc_init);
419 module_exit(efi_rtc_exit);
420
421 MODULE_LICENSE("GPL");
422
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