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/*
* EFI Time Services Driver for Linux
*
* Copyright (C) 1999 Hewlett-Packard Co
* Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
*
* Based on skeleton from the drivers/char/rtc.c driver by P. Gortmaker
*
* This code provides a architected & portable interface to the real time
* clock by using EFI instead of direct bit fiddling. The functionalities are
* quite different from the rtc.c driver. The only way to talk to the device
* is by using ioctl(). There is a /proc interface which provides the raw
* information.
*
* Please note that we have kept the API as close as possible from the
* legacy RTC. The standard /sbin/hwclock program should work normally
* when used to get/set the time.
*
* NOTES:
* - Locking is required for safe execution of EFI calls with regards
* to interrrupts and SMP.
*
* TODO (December 1999):
* - provide the API to set/get the WakeUp Alarm (different from the
* rtc.c alarm).
* - SMP testing
* - Add module support
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rtc.h>
#include <linux/proc_fs.h>
#include <asm/efi.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#define EFI_RTC_VERSION "0.2"
#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
/*
* EFI Epoch is 1/1/1998
*/
#define EFI_RTC_EPOCH 1998
static spinlock_t efi_rtc_lock = SPIN_LOCK_UNLOCKED;
static int efi_rtc_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg);
#define is_leap(year) \
((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
static const unsigned short int __mon_yday[2][13] =
{
/* Normal years. */
{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
/* Leap years. */
{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
};
/*
* returns day of the year [0-365]
*/
static inline int
compute_yday(efi_time_t *eft)
{
/* efi_time_t.month is in the [1-12] so, we need -1 */
return __mon_yday[is_leap(eft->year)][eft->month-1]+ eft->day -1;
}
/*
* returns day of the week [0-6] 0=Sunday
*
* Don't try to provide a year that's before 1998, please !
*/
static int
compute_wday(efi_time_t *eft)
{
int y;
int ndays = 0;
if ( eft->year < 1998 ) {
printk(KERN_ERR "efirtc: EFI year < 1998, invalid date\n");
return -1;
}
for(y=EFI_RTC_EPOCH; y < eft->year; y++ ) {
ndays += 365 + (is_leap(y) ? 1 : 0);
}
ndays += compute_yday(eft);
/*
* 4=1/1/1998 was a Thursday
*/
return (ndays + 4) % 7;
}
static void
convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)
{
eft->year = wtime->tm_year + 1900;
eft->month = wtime->tm_mon + 1;
eft->day = wtime->tm_mday;
eft->hour = wtime->tm_hour;
eft->minute = wtime->tm_min;
eft->second = wtime->tm_sec;
eft->nanosecond = 0;
eft->daylight = wtime->tm_isdst ? EFI_ISDST: 0;
eft->timezone = EFI_UNSPECIFIED_TIMEZONE;
}
static void
convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
{
wtime->tm_sec = eft->second;
wtime->tm_min = eft->minute;
wtime->tm_hour = eft->hour;
wtime->tm_mday = eft->day;
wtime->tm_mon = eft->month - 1;
wtime->tm_year = eft->year - 1900;
/* day of the week [0-6], Sunday=0 */
wtime->tm_wday = compute_wday(eft);
/* day in the year [1-365]*/
wtime->tm_yday = compute_yday(eft);
switch (eft->daylight & EFI_ISDST) {
case EFI_ISDST:
wtime->tm_isdst = 1;
break;
case EFI_TIME_ADJUST_DAYLIGHT:
wtime->tm_isdst = 0;
break;
default:
wtime->tm_isdst = -1;
}
}
static int
efi_rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
efi_status_t status;
unsigned long flags;
efi_time_t eft;
efi_time_cap_t cap;
struct rtc_time wtime;
struct rtc_wkalrm *ewp;
unsigned char enabled, pending;
switch (cmd) {
case RTC_UIE_ON:
case RTC_UIE_OFF:
case RTC_PIE_ON:
case RTC_PIE_OFF:
case RTC_AIE_ON:
case RTC_AIE_OFF:
case RTC_ALM_SET:
case RTC_ALM_READ:
case RTC_IRQP_READ:
case RTC_IRQP_SET:
case RTC_EPOCH_READ:
case RTC_EPOCH_SET:
return -EINVAL;
case RTC_RD_TIME:
spin_lock_irqsave(&efi_rtc_lock, flags);
status = efi.get_time(&eft, &cap);
spin_unlock_irqrestore(&efi_rtc_lock,flags);
if (status != EFI_SUCCESS) {
/* should never happen */
printk(KERN_ERR "efitime: can't read time\n");
return -EINVAL;
}
convert_from_efi_time(&eft, &wtime);
return copy_to_user((void *)arg, &wtime, sizeof (struct rtc_time)) ? - EFAULT : 0;
case RTC_SET_TIME:
if (!capable(CAP_SYS_TIME)) return -EACCES;
if (copy_from_user(&wtime, (struct rtc_time *)arg, sizeof(struct rtc_time)) )
return -EFAULT;
convert_to_efi_time(&wtime, &eft);
spin_lock_irqsave(&efi_rtc_lock, flags);
status = efi.set_time(&eft);
spin_unlock_irqrestore(&efi_rtc_lock,flags);
return status == EFI_SUCCESS ? 0 : -EINVAL;
case RTC_WKALM_SET:
if (!capable(CAP_SYS_TIME)) return -EACCES;
ewp = (struct rtc_wkalrm *)arg;
if ( get_user(enabled, &ewp->enabled)
|| copy_from_user(&wtime, &ewp->time, sizeof(struct rtc_time)) )
return -EFAULT;
convert_to_efi_time(&wtime, &eft);
spin_lock_irqsave(&efi_rtc_lock, flags);
/*
* XXX Fixme:
* As of EFI 0.92 with the firmware I have on my
* machine this call does not seem to work quite
* right
*/
status = efi.set_wakeup_time((efi_bool_t)enabled, &eft);
spin_unlock_irqrestore(&efi_rtc_lock,flags);
return status == EFI_SUCCESS ? 0 : -EINVAL;
case RTC_WKALM_RD:
spin_lock_irqsave(&efi_rtc_lock, flags);
status = efi.get_wakeup_time((efi_bool_t *)&enabled, (efi_bool_t *)&pending, &eft);
spin_unlock_irqrestore(&efi_rtc_lock,flags);
if (status != EFI_SUCCESS) return -EINVAL;
ewp = (struct rtc_wkalrm *)arg;
if ( put_user(enabled, &ewp->enabled)
|| put_user(pending, &ewp->pending)) return -EFAULT;
convert_from_efi_time(&eft, &wtime);
return copy_to_user((void *)&ewp->time, &wtime, sizeof(struct rtc_time)) ? -EFAULT : 0;
}
return -EINVAL;
}
/*
* We enforce only one user at a time here with the open/close.
* Also clear the previous interrupt data on an open, and clean
* up things on a close.
*/
static int
efi_rtc_open(struct inode *inode, struct file *file)
{
/*
* nothing special to do here
* We do accept multiple open files at the same time as we
* synchronize on the per call operation.
*/
return 0;
}
static int
efi_rtc_close(struct inode *inode, struct file *file)
{
return 0;
}
/*
* The various file operations we support.
*/
static struct file_operations efi_rtc_fops = {
owner: THIS_MODULE,
ioctl: efi_rtc_ioctl,
open: efi_rtc_open,
release: efi_rtc_close,
};
static struct miscdevice efi_rtc_dev=
{
EFI_RTC_MINOR,
"efirtc",
&efi_rtc_fops
};
/*
* We export RAW EFI information to /proc/efirtc
*/
static int
efi_rtc_get_status(char *buf)
{
efi_time_t eft, alm;
efi_time_cap_t cap;
char *p = buf;
efi_bool_t enabled, pending;
unsigned long flags;
spin_lock_irqsave(&efi_rtc_lock, flags);
efi.get_time(&eft, &cap);
efi.get_wakeup_time(&enabled, &pending, &alm);
spin_unlock_irqrestore(&efi_rtc_lock,flags);
p += sprintf(p,
"Time :\n"
"Year : %u\n"
"Month : %u\n"
"Day : %u\n"
"Hour : %u\n"
"Minute : %u\n"
"Second : %u\n"
"Nanosecond: %u\n"
"Daylight : %u\n",
eft.year, eft.month, eft.day, eft.hour, eft.minute,
eft.second, eft.nanosecond, eft.daylight);
if ( eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
p += sprintf(p, "Timezone : unspecified\n");
else
/* XXX fixme: convert to string? */
p += sprintf(p, "Timezone : %u\n", eft.timezone);
p += sprintf(p,
"\nWakeup Alm:\n"
"Enabled : %s\n"
"Pending : %s\n"
"Year : %u\n"
"Month : %u\n"
"Day : %u\n"
"Hour : %u\n"
"Minute : %u\n"
"Second : %u\n"
"Nanosecond: %u\n"
"Daylight : %u\n",
enabled == 1 ? "Yes" : "No",
pending == 1 ? "Yes" : "No",
alm.year, alm.month, alm.day, alm.hour, alm.minute,
alm.second, alm.nanosecond, alm.daylight);
if ( eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
p += sprintf(p, "Timezone : unspecified\n");
else
/* XXX fixme: convert to string? */
p += sprintf(p, "Timezone : %u\n", eft.timezone);
/*
* now prints the capabilities
*/
p += sprintf(p,
"\nClock Cap :\n"
"Resolution: %u\n"
"Accuracy : %u\n"
"SetstoZero: %u\n",
cap.resolution, cap.accuracy, cap.sets_to_zero);
return p - buf;
}
static int
efi_rtc_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len = efi_rtc_get_status(page);
if (len <= off+count) *eof = 1;
*start = page + off;
len -= off;
if (len>count) len = count;
if (len<0) len = 0;
return len;
}
static int __init
efi_rtc_init(void)
{
printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);
misc_register(&efi_rtc_dev);
create_proc_read_entry ("efirtc", 0, NULL, efi_rtc_read_proc, NULL);
return 0;
}
static void __exit
efi_rtc_exit(void)
{
/* not yet used */
}
module_init(efi_rtc_init);
module_exit(efi_rtc_exit);
MODULE_LICENSE("GPL");
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