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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 | |
49 | static DEFINE_SPINLOCK(efi_rtc_lock); |
50 | |
51 | static 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 | |
57 | static 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 | */ |
68 | static inline int |
69 | compute_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 | */ |
79 | static int |
80 | compute_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 | |
101 | static void |
102 | convert_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 | |
116 | static void |
117 | convert_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 | |
146 | static 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 | |
263 | static 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 | |
273 | static 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 | |
282 | static 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 | |
290 | static 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 | */ |
299 | static int |
300 | efi_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 | |
364 | static int |
365 | efi_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 | |
377 | static int __init |
378 | efi_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 | |
402 | static void __exit |
403 | efi_rtc_exit(void) |
404 | { |
405 | /* not yet used */ |
406 | } |
407 | |
408 | module_init(efi_rtc_init); |
409 | module_exit(efi_rtc_exit); |
410 | |
411 | MODULE_LICENSE("GPL"); |
412 |
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