1/* 2 * rtc-efi: RTC Class Driver for EFI-based systems 3 * 4 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P. 5 * 6 * Author: dann frazier <dannf@hp.com> 7 * Based on efirtc.c by Stephane Eranian 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License as published by the 11 * Free Software Foundation; either version 2 of the License, or (at your 12 * option) any later version. 13 * 14 */ 15 16#include <linux/kernel.h> 17#include <linux/module.h> 18#include <linux/time.h> 19#include <linux/platform_device.h> 20#include <linux/rtc.h> 21#include <linux/efi.h> 22 23#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT) 24/* 25 * EFI Epoch is 1/1/1998 26 */ 27#define EFI_RTC_EPOCH 1998 28 29/* 30 * returns day of the year [0-365] 31 */ 32static inline int 33compute_yday(efi_time_t *eft) 34{ 35 /* efi_time_t.month is in the [1-12] so, we need -1 */ 36 return rtc_year_days(eft->day - 1, eft->month - 1, eft->year); 37} 38/* 39 * returns day of the week [0-6] 0=Sunday 40 * 41 * Don't try to provide a year that's before 1998, please ! 42 */ 43static int 44compute_wday(efi_time_t *eft) 45{ 46 int y; 47 int ndays = 0; 48 49 if (eft->year < 1998) { 50 printk(KERN_ERR "efirtc: EFI year < 1998, invalid date\n"); 51 return -1; 52 } 53 54 for (y = EFI_RTC_EPOCH; y < eft->year; y++) 55 ndays += 365 + (is_leap_year(y) ? 1 : 0); 56 57 ndays += compute_yday(eft); 58 59 /* 60 * 4=1/1/1998 was a Thursday 61 */ 62 return (ndays + 4) % 7; 63} 64 65static void 66convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft) 67{ 68 eft->year = wtime->tm_year + 1900; 69 eft->month = wtime->tm_mon + 1; 70 eft->day = wtime->tm_mday; 71 eft->hour = wtime->tm_hour; 72 eft->minute = wtime->tm_min; 73 eft->second = wtime->tm_sec; 74 eft->nanosecond = 0; 75 eft->daylight = wtime->tm_isdst ? EFI_ISDST : 0; 76 eft->timezone = EFI_UNSPECIFIED_TIMEZONE; 77} 78 79static void 80convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime) 81{ 82 memset(wtime, 0, sizeof(*wtime)); 83 wtime->tm_sec = eft->second; 84 wtime->tm_min = eft->minute; 85 wtime->tm_hour = eft->hour; 86 wtime->tm_mday = eft->day; 87 wtime->tm_mon = eft->month - 1; 88 wtime->tm_year = eft->year - 1900; 89 90 /* day of the week [0-6], Sunday=0 */ 91 wtime->tm_wday = compute_wday(eft); 92 93 /* day in the year [1-365]*/ 94 wtime->tm_yday = compute_yday(eft); 95 96 97 switch (eft->daylight & EFI_ISDST) { 98 case EFI_ISDST: 99 wtime->tm_isdst = 1; 100 break; 101 case EFI_TIME_ADJUST_DAYLIGHT: 102 wtime->tm_isdst = 0; 103 break; 104 default: 105 wtime->tm_isdst = -1; 106 } 107} 108 109static int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) 110{ 111 efi_time_t eft; 112 efi_status_t status; 113 114 /* 115 * As of EFI v1.10, this call always returns an unsupported status 116 */ 117 status = efi.get_wakeup_time((efi_bool_t *)&wkalrm->enabled, 118 (efi_bool_t *)&wkalrm->pending, &eft); 119 120 if (status != EFI_SUCCESS) 121 return -EINVAL; 122 123 convert_from_efi_time(&eft, &wkalrm->time); 124 125 return rtc_valid_tm(&wkalrm->time); 126} 127 128static int efi_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm) 129{ 130 efi_time_t eft; 131 efi_status_t status; 132 133 convert_to_efi_time(&wkalrm->time, &eft); 134 135 status = efi.set_wakeup_time((efi_bool_t)wkalrm->enabled, &eft); 136 137 printk(KERN_WARNING "write status is %d\n", (int)status); 138 139 return status == EFI_SUCCESS ? 0 : -EINVAL; 140} 141 142static int efi_read_time(struct device *dev, struct rtc_time *tm) 143{ 144 efi_status_t status; 145 efi_time_t eft; 146 efi_time_cap_t cap; 147 148 status = efi.get_time(&eft, &cap); 149 150 if (status != EFI_SUCCESS) { 151 /* should never happen */ 152 printk(KERN_ERR "efitime: can't read time\n"); 153 return -EINVAL; 154 } 155 156 convert_from_efi_time(&eft, tm); 157 158 return rtc_valid_tm(tm); 159} 160 161static int efi_set_time(struct device *dev, struct rtc_time *tm) 162{ 163 efi_status_t status; 164 efi_time_t eft; 165 166 convert_to_efi_time(tm, &eft); 167 168 status = efi.set_time(&eft); 169 170 return status == EFI_SUCCESS ? 0 : -EINVAL; 171} 172 173static const struct rtc_class_ops efi_rtc_ops = { 174 .read_time = efi_read_time, 175 .set_time = efi_set_time, 176 .read_alarm = efi_read_alarm, 177 .set_alarm = efi_set_alarm, 178}; 179 180static int __init efi_rtc_probe(struct platform_device *dev) 181{ 182 struct rtc_device *rtc; 183 184 rtc = rtc_device_register("rtc-efi", &dev->dev, &efi_rtc_ops, 185 THIS_MODULE); 186 if (IS_ERR(rtc)) 187 return PTR_ERR(rtc); 188 189 platform_set_drvdata(dev, rtc); 190 191 return 0; 192} 193 194static int __exit efi_rtc_remove(struct platform_device *dev) 195{ 196 struct rtc_device *rtc = platform_get_drvdata(dev); 197 198 rtc_device_unregister(rtc); 199 200 return 0; 201} 202 203static struct platform_driver efi_rtc_driver = { 204 .driver = { 205 .name = "rtc-efi", 206 .owner = THIS_MODULE, 207 }, 208 .probe = efi_rtc_probe, 209 .remove = __exit_p(efi_rtc_remove), 210}; 211 212static int __init efi_rtc_init(void) 213{ 214 return platform_driver_probe(&efi_rtc_driver, efi_rtc_probe); 215} 216 217static void __exit efi_rtc_exit(void) 218{ 219 platform_driver_unregister(&efi_rtc_driver); 220} 221 222module_init(efi_rtc_init); 223module_exit(efi_rtc_exit); 224 225MODULE_AUTHOR("dann frazier <dannf@hp.com>"); 226MODULE_LICENSE("GPL"); 227MODULE_DESCRIPTION("EFI RTC driver"); 228