// SPDX-License-Identifier: GPL-2.0-or-later/* * rtc-efi: RTC Class Driver for EFI-based systems * * Copyright (C) 2009 Hewlett-Packard Development Company, L.P. * * Author: dann frazier <dannf@dannf.org> * Based on efirtc.c by Stephane Eranian */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/kernel.h>#include <linux/module.h>#include <linux/stringify.h>#include <linux/time.h>#include <linux/platform_device.h>#include <linux/rtc.h>#include <linux/efi.h> #define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT) /* * returns day of the year [0-365] */static inline intcompute_yday(efi_time_t *eft){	/* efi_time_t.month is in the [1-12] so, we need -1 */	return rtc_year_days(eft->day, eft->month - 1, eft->year);} /* * returns day of the week [0-6] 0=Sunday */static intcompute_wday(efi_time_t *eft, int yday){	int ndays = eft->year * (365 % 7)		    + (eft->year - 1) / 4		    - (eft->year - 1) / 100		    + (eft->year - 1) / 400		    + yday; 	/*	 * 1/1/0000 may or may not have been a Sunday (if it ever existed at	 * all) but assuming it was makes this calculation work correctly.	 */	return ndays % 7;} static voidconvert_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 boolconvert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime){	memset(wtime, 0, sizeof(*wtime)); 	if (eft->second >= 60)		return false;	wtime->tm_sec  = eft->second; 	if (eft->minute >= 60)		return false;	wtime->tm_min  = eft->minute; 	if (eft->hour >= 24)		return false;	wtime->tm_hour = eft->hour; 	if (!eft->day || eft->day > 31)		return false;	wtime->tm_mday = eft->day; 	if (!eft->month || eft->month > 12)		return false;	wtime->tm_mon  = eft->month - 1; 	if (eft->year < 1900 || eft->year > 9999)		return false;	wtime->tm_year = eft->year - 1900; 	/* day in the year [1-365]*/	wtime->tm_yday = compute_yday(eft); 	/* day of the week [0-6], Sunday=0 */	wtime->tm_wday = compute_wday(eft, wtime->tm_yday); 	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;	} 	return true;} static int efi_read_time(struct device *dev, struct rtc_time *tm){	efi_status_t status;	efi_time_t eft;	efi_time_cap_t cap; 	status = efi.get_time(&eft, &cap); 	if (status != EFI_SUCCESS) {		/* should never happen */		dev_err_once(dev, "can't read time\n");		return -EINVAL;	} 	if (!convert_from_efi_time(&eft, tm))		return -EIO; 	return 0;} static int efi_set_time(struct device *dev, struct rtc_time *tm){	efi_status_t status;	efi_time_t eft; 	convert_to_efi_time(tm, &eft); 	status = efi.set_time(&eft); 	return status == EFI_SUCCESS ? 0 : -EINVAL;} static int efi_procfs(struct device *dev, struct seq_file *seq){	efi_time_t        eft;	efi_time_cap_t    cap; 	memset(&eft, 0, sizeof(eft));	memset(&cap, 0, sizeof(cap)); 	efi.get_time(&eft, &cap); 	seq_printf(seq,		   "Time\t\t: %u:%u:%u.%09u\n"		   "Date\t\t: %u-%u-%u\n"		   "Daylight\t: %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(seq, "Timezone\t: unspecified\n");	else		/* XXX fixme: convert to string? */		seq_printf(seq, "Timezone\t: %u\n", eft.timezone); 	/*	 * now prints the capabilities	 */	seq_printf(seq,		   "Resolution\t: %u\n"		   "Accuracy\t: %u\n"		   "SetstoZero\t: %u\n",		   cap.resolution, cap.accuracy, cap.sets_to_zero); 	return 0;} static const struct rtc_class_ops efi_rtc_ops = {	.read_time	= efi_read_time,	.set_time	= efi_set_time,	.proc		= efi_procfs,}; static int __init efi_rtc_probe(struct platform_device *dev){	struct rtc_device *rtc;	efi_time_t eft;	efi_time_cap_t cap; 	/* First check if the RTC is usable */	if (efi.get_time(&eft, &cap) != EFI_SUCCESS)		return -ENODEV; 	rtc = devm_rtc_allocate_device(&dev->dev);	if (IS_ERR(rtc))		return PTR_ERR(rtc); 	platform_set_drvdata(dev, rtc); 	rtc->ops = &efi_rtc_ops;	clear_bit(RTC_FEATURE_ALARM, rtc->features); 	device_init_wakeup(&dev->dev, true); 	return devm_rtc_register_device(rtc);} static struct platform_driver efi_rtc_driver = {	.driver = {		.name = "rtc-efi",	},}; module_platform_driver_probe(efi_rtc_driver, efi_rtc_probe); MODULE_AUTHOR("dann frazier <dannf@dannf.org>");MODULE_LICENSE("GPL");MODULE_DESCRIPTION("EFI RTC driver");MODULE_ALIAS("platform:rtc-efi");