367 lines
8.5 KiB
C
367 lines
8.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* EFI Time Services Driver for Linux
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*
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* Copyright (C) 1999 Hewlett-Packard Co
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* Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
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*
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* Based on skeleton from the drivers/char/rtc.c driver by P. Gortmaker
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*
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* This code provides an architected & portable interface to the real time
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* clock by using EFI instead of direct bit fiddling. The functionalities are
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* quite different from the rtc.c driver. The only way to talk to the device
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* is by using ioctl(). There is a /proc interface which provides the raw
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* information.
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*
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* Please note that we have kept the API as close as possible to the
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* legacy RTC. The standard /sbin/hwclock program should work normally
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* when used to get/set the time.
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*
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* NOTES:
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* - Locking is required for safe execution of EFI calls with regards
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* to interrupts and SMP.
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*
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* TODO (December 1999):
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* - provide the API to set/get the WakeUp Alarm (different from the
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* rtc.c alarm).
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* - SMP testing
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* - Add module support
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*/
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/miscdevice.h>
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#include <linux/init.h>
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#include <linux/rtc.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/efi.h>
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#include <linux/uaccess.h>
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#define EFI_RTC_VERSION "0.4"
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#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
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/*
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* EFI Epoch is 1/1/1998
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*/
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#define EFI_RTC_EPOCH 1998
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static DEFINE_SPINLOCK(efi_rtc_lock);
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static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg);
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#define is_leap(year) \
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((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
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static const unsigned short int __mon_yday[2][13] =
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{
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/* Normal years. */
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{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
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/* Leap years. */
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{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
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};
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/*
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* returns day of the year [0-365]
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*/
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static inline int
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compute_yday(efi_time_t *eft)
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{
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/* efi_time_t.month is in the [1-12] so, we need -1 */
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return __mon_yday[is_leap(eft->year)][eft->month-1]+ eft->day -1;
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}
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/*
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* returns day of the week [0-6] 0=Sunday
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*
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* Don't try to provide a year that's before 1998, please !
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*/
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static int
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compute_wday(efi_time_t *eft)
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{
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int y;
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int ndays = 0;
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if ( eft->year < 1998 ) {
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printk(KERN_ERR "efirtc: EFI year < 1998, invalid date\n");
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return -1;
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}
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for(y=EFI_RTC_EPOCH; y < eft->year; y++ ) {
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ndays += 365 + (is_leap(y) ? 1 : 0);
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}
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ndays += compute_yday(eft);
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/*
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* 4=1/1/1998 was a Thursday
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*/
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return (ndays + 4) % 7;
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}
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static void
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convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)
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{
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eft->year = wtime->tm_year + 1900;
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eft->month = wtime->tm_mon + 1;
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eft->day = wtime->tm_mday;
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eft->hour = wtime->tm_hour;
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eft->minute = wtime->tm_min;
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eft->second = wtime->tm_sec;
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eft->nanosecond = 0;
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eft->daylight = wtime->tm_isdst ? EFI_ISDST: 0;
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eft->timezone = EFI_UNSPECIFIED_TIMEZONE;
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}
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static void
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convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
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{
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memset(wtime, 0, sizeof(*wtime));
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wtime->tm_sec = eft->second;
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wtime->tm_min = eft->minute;
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wtime->tm_hour = eft->hour;
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wtime->tm_mday = eft->day;
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wtime->tm_mon = eft->month - 1;
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wtime->tm_year = eft->year - 1900;
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/* day of the week [0-6], Sunday=0 */
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wtime->tm_wday = compute_wday(eft);
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/* day in the year [1-365]*/
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wtime->tm_yday = compute_yday(eft);
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switch (eft->daylight & EFI_ISDST) {
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case EFI_ISDST:
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wtime->tm_isdst = 1;
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break;
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case EFI_TIME_ADJUST_DAYLIGHT:
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wtime->tm_isdst = 0;
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break;
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default:
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wtime->tm_isdst = -1;
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}
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}
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static long efi_rtc_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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efi_status_t status;
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unsigned long flags;
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efi_time_t eft;
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efi_time_cap_t cap;
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struct rtc_time wtime;
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struct rtc_wkalrm __user *ewp;
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unsigned char enabled, pending;
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switch (cmd) {
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case RTC_UIE_ON:
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case RTC_UIE_OFF:
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case RTC_PIE_ON:
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case RTC_PIE_OFF:
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case RTC_AIE_ON:
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case RTC_AIE_OFF:
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case RTC_ALM_SET:
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case RTC_ALM_READ:
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case RTC_IRQP_READ:
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case RTC_IRQP_SET:
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case RTC_EPOCH_READ:
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case RTC_EPOCH_SET:
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return -EINVAL;
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case RTC_RD_TIME:
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spin_lock_irqsave(&efi_rtc_lock, flags);
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status = efi.get_time(&eft, &cap);
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spin_unlock_irqrestore(&efi_rtc_lock,flags);
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if (status != EFI_SUCCESS) {
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/* should never happen */
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printk(KERN_ERR "efitime: can't read time\n");
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return -EINVAL;
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}
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convert_from_efi_time(&eft, &wtime);
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return copy_to_user((void __user *)arg, &wtime,
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sizeof (struct rtc_time)) ? - EFAULT : 0;
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case RTC_SET_TIME:
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if (!capable(CAP_SYS_TIME)) return -EACCES;
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if (copy_from_user(&wtime, (struct rtc_time __user *)arg,
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sizeof(struct rtc_time)) )
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return -EFAULT;
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convert_to_efi_time(&wtime, &eft);
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spin_lock_irqsave(&efi_rtc_lock, flags);
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status = efi.set_time(&eft);
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spin_unlock_irqrestore(&efi_rtc_lock,flags);
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return status == EFI_SUCCESS ? 0 : -EINVAL;
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case RTC_WKALM_SET:
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if (!capable(CAP_SYS_TIME)) return -EACCES;
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ewp = (struct rtc_wkalrm __user *)arg;
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if ( get_user(enabled, &ewp->enabled)
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|| copy_from_user(&wtime, &ewp->time, sizeof(struct rtc_time)) )
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return -EFAULT;
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convert_to_efi_time(&wtime, &eft);
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spin_lock_irqsave(&efi_rtc_lock, flags);
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/*
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* XXX Fixme:
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* As of EFI 0.92 with the firmware I have on my
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* machine this call does not seem to work quite
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* right
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*/
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status = efi.set_wakeup_time((efi_bool_t)enabled, &eft);
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spin_unlock_irqrestore(&efi_rtc_lock,flags);
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return status == EFI_SUCCESS ? 0 : -EINVAL;
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case RTC_WKALM_RD:
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spin_lock_irqsave(&efi_rtc_lock, flags);
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status = efi.get_wakeup_time((efi_bool_t *)&enabled, (efi_bool_t *)&pending, &eft);
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spin_unlock_irqrestore(&efi_rtc_lock,flags);
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if (status != EFI_SUCCESS) return -EINVAL;
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ewp = (struct rtc_wkalrm __user *)arg;
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if ( put_user(enabled, &ewp->enabled)
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|| put_user(pending, &ewp->pending)) return -EFAULT;
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convert_from_efi_time(&eft, &wtime);
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return copy_to_user(&ewp->time, &wtime,
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sizeof(struct rtc_time)) ? -EFAULT : 0;
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}
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return -ENOTTY;
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}
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/*
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* The various file operations we support.
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*/
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static const struct file_operations efi_rtc_fops = {
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.owner = THIS_MODULE,
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.unlocked_ioctl = efi_rtc_ioctl,
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.llseek = no_llseek,
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};
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static struct miscdevice efi_rtc_dev= {
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EFI_RTC_MINOR,
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"efirtc",
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&efi_rtc_fops
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};
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/*
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* We export RAW EFI information to /proc/driver/efirtc
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*/
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static int efi_rtc_proc_show(struct seq_file *m, void *v)
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{
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efi_time_t eft, alm;
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efi_time_cap_t cap;
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efi_bool_t enabled, pending;
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unsigned long flags;
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memset(&eft, 0, sizeof(eft));
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memset(&alm, 0, sizeof(alm));
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memset(&cap, 0, sizeof(cap));
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spin_lock_irqsave(&efi_rtc_lock, flags);
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efi.get_time(&eft, &cap);
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efi.get_wakeup_time(&enabled, &pending, &alm);
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spin_unlock_irqrestore(&efi_rtc_lock,flags);
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seq_printf(m,
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"Time : %u:%u:%u.%09u\n"
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"Date : %u-%u-%u\n"
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"Daylight : %u\n",
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eft.hour, eft.minute, eft.second, eft.nanosecond,
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eft.year, eft.month, eft.day,
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eft.daylight);
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if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
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seq_puts(m, "Timezone : unspecified\n");
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else
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/* XXX fixme: convert to string? */
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seq_printf(m, "Timezone : %u\n", eft.timezone);
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seq_printf(m,
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"Alarm Time : %u:%u:%u.%09u\n"
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"Alarm Date : %u-%u-%u\n"
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"Alarm Daylight : %u\n"
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"Enabled : %s\n"
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"Pending : %s\n",
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alm.hour, alm.minute, alm.second, alm.nanosecond,
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alm.year, alm.month, alm.day,
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alm.daylight,
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enabled == 1 ? "yes" : "no",
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pending == 1 ? "yes" : "no");
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if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
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seq_puts(m, "Timezone : unspecified\n");
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else
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/* XXX fixme: convert to string? */
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seq_printf(m, "Timezone : %u\n", alm.timezone);
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/*
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* now prints the capabilities
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*/
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seq_printf(m,
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"Resolution : %u\n"
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"Accuracy : %u\n"
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"SetstoZero : %u\n",
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cap.resolution, cap.accuracy, cap.sets_to_zero);
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return 0;
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}
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static int __init
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efi_rtc_init(void)
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{
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int ret;
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struct proc_dir_entry *dir;
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printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);
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ret = misc_register(&efi_rtc_dev);
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if (ret) {
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printk(KERN_ERR "efirtc: can't misc_register on minor=%d\n",
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EFI_RTC_MINOR);
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return ret;
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}
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dir = proc_create_single("driver/efirtc", 0, NULL, efi_rtc_proc_show);
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if (dir == NULL) {
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printk(KERN_ERR "efirtc: can't create /proc/driver/efirtc.\n");
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misc_deregister(&efi_rtc_dev);
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return -1;
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}
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return 0;
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}
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device_initcall(efi_rtc_init);
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/*
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MODULE_LICENSE("GPL");
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*/
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