efirtc.c 9.5 KB

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