drivers/char/efirtc.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * 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 an 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 to 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 interrupts 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/init.h>
 #include <linux/rtc.h>
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/efi.h>
 #include <linux/uaccess.h>


 #define EFI_RTC_VERSION		"0.4"

 #define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
 /*
  * EFI Epoch is 1/1/1998
  */
 #define EFI_RTC_EPOCH		1998

 static DEFINE_SPINLOCK(efi_rtc_lock);

 static long efi_rtc_ioctl(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)
 {
 	memset(wtime, 0, sizeof(*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 long efi_rtc_ioctl(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 __user *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 __user *)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 __user *)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 __user *)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 __user *)arg;

 			if (  put_user(enabled, &ewp->enabled)
 			   || put_user(pending, &ewp->pending)) return -EFAULT;

 			convert_from_efi_time(&eft, &wtime);

 			return copy_to_user(&ewp->time, &wtime,
 					    sizeof(struct rtc_time)) ? -EFAULT : 0;
 	}
 	return -ENOTTY;
 }

 /*
  *	The various file operations we support.
  */

 static const struct file_operations efi_rtc_fops = {
 	.owner		= THIS_MODULE,
 	.unlocked_ioctl	= efi_rtc_ioctl,
 	.llseek		= no_llseek,
 };

 static struct miscdevice efi_rtc_dev= {
 	EFI_RTC_MINOR,
 	"efirtc",
 	&efi_rtc_fops
 };

 /*
  *	We export RAW EFI information to /proc/driver/efirtc
  */
 static int efi_rtc_proc_show(struct seq_file *m, void *v)
 {
 	efi_time_t 	eft, alm;
 	efi_time_cap_t	cap;
 	efi_bool_t	enabled, pending;
 	unsigned long	flags;

 	memset(&eft, 0, sizeof(eft));
 	memset(&alm, 0, sizeof(alm));
 	memset(&cap, 0, sizeof(cap));

 	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);

 	seq_printf(m,
 		   "Time           : %u:%u:%u.%09u\n"
 		   "Date           : %u-%u-%u\n"
 		   "Daylight       : %u\n",
 		   eft.hour, eft.minute, eft.second, eft.nanosecond,
 		   eft.year, eft.month, eft.day,
 		   eft.daylight);

 	if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
 		seq_puts(m, "Timezone       : unspecified\n");
 	else
 		/* XXX fixme: convert to string? */
 		seq_printf(m, "Timezone       : %u\n", eft.timezone);


 	seq_printf(m,
 		   "Alarm Time     : %u:%u:%u.%09u\n"
 		   "Alarm Date     : %u-%u-%u\n"
 		   "Alarm Daylight : %u\n"
 		   "Enabled        : %s\n"
 		   "Pending        : %s\n",
 		   alm.hour, alm.minute, alm.second, alm.nanosecond,
 		   alm.year, alm.month, alm.day,
 		   alm.daylight,
 		   enabled == 1 ? "yes" : "no",
 		   pending == 1 ? "yes" : "no");

 	if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
 		seq_puts(m, "Timezone       : unspecified\n");
 	else
 		/* XXX fixme: convert to string? */
 		seq_printf(m, "Timezone       : %u\n", alm.timezone);

 	/*
 	 * now prints the capabilities
 	 */
 	seq_printf(m,
 		   "Resolution     : %u\n"
 		   "Accuracy       : %u\n"
 		   "SetstoZero     : %u\n",
 		   cap.resolution, cap.accuracy, cap.sets_to_zero);

 	return 0;
 }
 static int __init
 efi_rtc_init(void)
 {
 	int ret;
 	struct proc_dir_entry *dir;

 	printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);

 	ret = misc_register(&efi_rtc_dev);
 	if (ret) {
 		printk(KERN_ERR "efirtc: can't misc_register on minor=%d\n",
 				EFI_RTC_MINOR);
 		return ret;
 	}

 	dir = proc_create_single("driver/efirtc", 0, NULL, efi_rtc_proc_show);
 	if (dir == NULL) {
 		printk(KERN_ERR "efirtc: can't create /proc/driver/efirtc.\n");
 		misc_deregister(&efi_rtc_dev);
 		return -1;
 	}
 	return 0;
 }
 device_initcall(efi_rtc_init);

 /*
 MODULE_LICENSE("GPL");
 */
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* 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 an 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 to 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 interrupts 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/init.h>
	#include <linux/rtc.h>
	#include <linux/proc_fs.h>
	#include <linux/seq_file.h>
	#include <linux/efi.h>
	#include <linux/uaccess.h>


	#define EFI_RTC_VERSION "0.4"

	#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT\|EFI_TIME_IN_DAYLIGHT)
	/*
	* EFI Epoch is 1/1/1998
	*/
	#define EFI_RTC_EPOCH 1998

	static DEFINE_SPINLOCK(efi_rtc_lock);

	static long efi_rtc_ioctl(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)
	{
	memset(wtime, 0, sizeof(*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 long efi_rtc_ioctl(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 __user *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 __user *)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 __user *)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 __user *)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 __user *)arg;

	if ( put_user(enabled, &ewp->enabled)
	\|\| put_user(pending, &ewp->pending)) return -EFAULT;

	convert_from_efi_time(&eft, &wtime);

	return copy_to_user(&ewp->time, &wtime,
	sizeof(struct rtc_time)) ? -EFAULT : 0;
	}
	return -ENOTTY;
	}

	/*
	* The various file operations we support.
	*/

	static const struct file_operations efi_rtc_fops = {
	.owner = THIS_MODULE,
	.unlocked_ioctl = efi_rtc_ioctl,
	.llseek = no_llseek,
	};

	static struct miscdevice efi_rtc_dev= {
	EFI_RTC_MINOR,
	"efirtc",
	&efi_rtc_fops
	};

	/*
	* We export RAW EFI information to /proc/driver/efirtc
	*/
	static int efi_rtc_proc_show(struct seq_file m, void v)
	{
	efi_time_t eft, alm;
	efi_time_cap_t cap;
	efi_bool_t enabled, pending;
	unsigned long flags;

	memset(&eft, 0, sizeof(eft));
	memset(&alm, 0, sizeof(alm));
	memset(&cap, 0, sizeof(cap));

	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);

	seq_printf(m,
	"Time : %u:%u:%u.%09u\n"
	"Date : %u-%u-%u\n"
	"Daylight : %u\n",
	eft.hour, eft.minute, eft.second, eft.nanosecond,
	eft.year, eft.month, eft.day,
	eft.daylight);

	if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
	seq_puts(m, "Timezone : unspecified\n");
	else
	/* XXX fixme: convert to string? */
	seq_printf(m, "Timezone : %u\n", eft.timezone);


	seq_printf(m,
	"Alarm Time : %u:%u:%u.%09u\n"
	"Alarm Date : %u-%u-%u\n"
	"Alarm Daylight : %u\n"
	"Enabled : %s\n"
	"Pending : %s\n",
	alm.hour, alm.minute, alm.second, alm.nanosecond,
	alm.year, alm.month, alm.day,
	alm.daylight,
	enabled == 1 ? "yes" : "no",
	pending == 1 ? "yes" : "no");

	if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
	seq_puts(m, "Timezone : unspecified\n");
	else
	/* XXX fixme: convert to string? */
	seq_printf(m, "Timezone : %u\n", alm.timezone);

	/*
	* now prints the capabilities
	*/
	seq_printf(m,
	"Resolution : %u\n"
	"Accuracy : %u\n"
	"SetstoZero : %u\n",
	cap.resolution, cap.accuracy, cap.sets_to_zero);

	return 0;
	}
	static int __init
	efi_rtc_init(void)
	{
	int ret;
	struct proc_dir_entry *dir;

	printk(KERN_INFO "EFI Time Services Driver v%s\n", EFI_RTC_VERSION);

	ret = misc_register(&efi_rtc_dev);
	if (ret) {
	printk(KERN_ERR "efirtc: can't misc_register on minor=%d\n",
	EFI_RTC_MINOR);
	return ret;
	}

	dir = proc_create_single("driver/efirtc", 0, NULL, efi_rtc_proc_show);
	if (dir == NULL) {
	printk(KERN_ERR "efirtc: can't create /proc/driver/efirtc.\n");
	misc_deregister(&efi_rtc_dev);
	return -1;
	}
	return 0;
	}
	device_initcall(efi_rtc_init);

	/*
	MODULE_LICENSE("GPL");
	*/