/* * rtc-efi: RTC Class Driver for EFI-based systems * * Copyright (C) 2009 Hewlett-Packard Development Company, L.P. * * Author: dann frazier <dannf@hp.com> * Based on efirtc.c by Stephane Eranian * *  This program is free software; you can redistribute  it and/or modify it *  under  the terms of  the GNU General  Public License as published by the *  Free Software Foundation;  either version 2 of the  License, or (at your *  option) any later version. * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/kernel.h>#include <linux/module.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)/* * EFI Epoch is 1/1/1998 */#define EFI_RTC_EPOCH		1998 /* * 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 - 1, eft->month - 1, eft->year);}/* * returns day of the week [0-6] 0=Sunday * * Don't try to provide a year that's before 1998, please ! */static intcompute_wday(efi_time_t *eft){	int y;	int ndays = 0; 	if (eft->year < 1998) {		pr_err("EFI year < 1998, invalid date\n");		return -1;	} 	for (y = EFI_RTC_EPOCH; y < eft->year; y++)		ndays += 365 + (is_leap_year(y) ? 1 : 0); 	ndays += compute_yday(eft); 	/*	 * 4=1/1/1998 was a Thursday	 */	return (ndays + 4) % 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 voidconvert_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 int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm){	efi_time_t eft;	efi_status_t status; 	/*	 * As of EFI v1.10, this call always returns an unsupported status	 */	status = efi.get_wakeup_time((efi_bool_t *)&wkalrm->enabled,				     (efi_bool_t *)&wkalrm->pending, &eft); 	if (status != EFI_SUCCESS)		return -EINVAL; 	convert_from_efi_time(&eft, &wkalrm->time); 	return rtc_valid_tm(&wkalrm->time);} static int efi_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm){	efi_time_t eft;	efi_status_t status; 	convert_to_efi_time(&wkalrm->time, &eft); 	/*	 * XXX Fixme:	 * As of EFI 0.92 with the firmware I have on my	 * machine this call does not seem to work quite	 * right	 *	 * As of v1.10, this call always returns an unsupported status	 */	status = efi.set_wakeup_time((efi_bool_t)wkalrm->enabled, &eft); 	dev_warn(dev, "write status is %d\n", (int)status); 	return status == EFI_SUCCESS ? 0 : -EINVAL;} 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(dev, "can't read time\n");		return -EINVAL;	} 	convert_from_efi_time(&eft, tm); 	return rtc_valid_tm(tm);} 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 const struct rtc_class_ops efi_rtc_ops = {	.read_time = efi_read_time,	.set_time = efi_set_time,	.read_alarm = efi_read_alarm,	.set_alarm = efi_set_alarm,}; static int __init efi_rtc_probe(struct platform_device *dev){	struct rtc_device *rtc; 	rtc = devm_rtc_device_register(&dev->dev, "rtc-efi", &efi_rtc_ops,					THIS_MODULE);	if (IS_ERR(rtc))		return PTR_ERR(rtc); 	platform_set_drvdata(dev, rtc); 	return 0;} static struct platform_driver efi_rtc_driver = {	.driver = {		.name = "rtc-efi",		.owner = THIS_MODULE,	},}; module_platform_driver_probe(efi_rtc_driver, efi_rtc_probe); MODULE_AUTHOR("dann frazier <dannf@hp.com>");MODULE_LICENSE("GPL");MODULE_DESCRIPTION("EFI RTC driver");