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 #include <asm/system.h>
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
50 static DEFINE_SPINLOCK(efi_rtc_lock);
51
52 static 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
58 static 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 */
69 static inline int
compute_yday(efi_time_t * eft)70 compute_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 */
80 static int
compute_wday(efi_time_t * eft)81 compute_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
102 static void
convert_to_efi_time(struct rtc_time * wtime,efi_time_t * eft)103 convert_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
117 static void
convert_from_efi_time(efi_time_t * eft,struct rtc_time * wtime)118 convert_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
efi_rtc_ioctl(struct file * file,unsigned int cmd,unsigned long arg)147 static 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
efi_rtc_open(struct inode * inode,struct file * file)264 static 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
efi_rtc_close(struct inode * inode,struct file * file)274 static 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
283 static 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
291 static 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 */
300 static int
efi_rtc_get_status(char * buf)301 efi_rtc_get_status(char *buf)
302 {
303 efi_time_t eft, alm;
304 efi_time_cap_t cap;
305 char *p = buf;
306 efi_bool_t enabled, pending;
307 unsigned long flags;
308
309 memset(&eft, 0, sizeof(eft));
310 memset(&alm, 0, sizeof(alm));
311 memset(&cap, 0, sizeof(cap));
312
313 spin_lock_irqsave(&efi_rtc_lock, flags);
314
315 efi.get_time(&eft, &cap);
316 efi.get_wakeup_time(&enabled, &pending, &alm);
317
318 spin_unlock_irqrestore(&efi_rtc_lock,flags);
319
320 p += sprintf(p,
321 "Time : %u:%u:%u.%09u\n"
322 "Date : %u-%u-%u\n"
323 "Daylight : %u\n",
324 eft.hour, eft.minute, eft.second, eft.nanosecond,
325 eft.year, eft.month, eft.day,
326 eft.daylight);
327
328 if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
329 p += sprintf(p, "Timezone : unspecified\n");
330 else
331 /* XXX fixme: convert to string? */
332 p += sprintf(p, "Timezone : %u\n", eft.timezone);
333
334
335 p += sprintf(p,
336 "Alarm Time : %u:%u:%u.%09u\n"
337 "Alarm Date : %u-%u-%u\n"
338 "Alarm Daylight : %u\n"
339 "Enabled : %s\n"
340 "Pending : %s\n",
341 alm.hour, alm.minute, alm.second, alm.nanosecond,
342 alm.year, alm.month, alm.day,
343 alm.daylight,
344 enabled == 1 ? "yes" : "no",
345 pending == 1 ? "yes" : "no");
346
347 if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
348 p += sprintf(p, "Timezone : unspecified\n");
349 else
350 /* XXX fixme: convert to string? */
351 p += sprintf(p, "Timezone : %u\n", alm.timezone);
352
353 /*
354 * now prints the capabilities
355 */
356 p += sprintf(p,
357 "Resolution : %u\n"
358 "Accuracy : %u\n"
359 "SetstoZero : %u\n",
360 cap.resolution, cap.accuracy, cap.sets_to_zero);
361
362 return p - buf;
363 }
364
365 static int
efi_rtc_read_proc(char * page,char ** start,off_t off,int count,int * eof,void * data)366 efi_rtc_read_proc(char *page, char **start, off_t off,
367 int count, int *eof, void *data)
368 {
369 int len = efi_rtc_get_status(page);
370 if (len <= off+count) *eof = 1;
371 *start = page + off;
372 len -= off;
373 if (len>count) len = count;
374 if (len<0) len = 0;
375 return len;
376 }
377
378 static int __init
efi_rtc_init(void)379 efi_rtc_init(void)
380 {
381 int ret;
382 struct proc_dir_entry *dir;
383
384 printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);
385
386 ret = misc_register(&efi_rtc_dev);
387 if (ret) {
388 printk(KERN_ERR "efirtc: can't misc_register on minor=%d\n",
389 EFI_RTC_MINOR);
390 return ret;
391 }
392
393 dir = create_proc_read_entry ("driver/efirtc", 0, NULL,
394 efi_rtc_read_proc, NULL);
395 if (dir == NULL) {
396 printk(KERN_ERR "efirtc: can't create /proc/driver/efirtc.\n");
397 misc_deregister(&efi_rtc_dev);
398 return -1;
399 }
400 return 0;
401 }
402
403 static void __exit
efi_rtc_exit(void)404 efi_rtc_exit(void)
405 {
406 /* not yet used */
407 }
408
409 module_init(efi_rtc_init);
410 module_exit(efi_rtc_exit);
411
412 MODULE_LICENSE("GPL");
413