| 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"); |