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 */ 32 static inline int 33 compute_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 */ 43 static int 44 compute_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 65 static void 66 convert_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 79 static void 80 convert_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 } 108 109 static 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 } 127 128 static 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 /* 136 * XXX Fixme: 137 * As of EFI 0.92 with the firmware I have on my 138 * machine this call does not seem to work quite 139 * right 140 * 141 * As of v1.10, this call always returns an unsupported status 142 */ 143 status = efi.set_wakeup_time((efi_bool_t)wkalrm->enabled, &eft); 144 145 printk(KERN_WARNING "write status is %d\n", (int)status); 146 147 return status == EFI_SUCCESS ? 0 : -EINVAL; 148 } 149 150 static int efi_read_time(struct device *dev, struct rtc_time *tm) 151 { 152 efi_status_t status; 153 efi_time_t eft; 154 efi_time_cap_t cap; 155 156 status = efi.get_time(&eft, &cap); 157 158 if (status != EFI_SUCCESS) { 159 /* should never happen */ 160 printk(KERN_ERR "efitime: can't read time\n"); 161 return -EINVAL; 162 } 163 164 convert_from_efi_time(&eft, tm); 165 166 return rtc_valid_tm(tm); 167 } 168 169 static int efi_set_time(struct device *dev, struct rtc_time *tm) 170 { 171 efi_status_t status; 172 efi_time_t eft; 173 174 convert_to_efi_time(tm, &eft); 175 176 status = efi.set_time(&eft); 177 178 return status == EFI_SUCCESS ? 0 : -EINVAL; 179 } 180 181 static const struct rtc_class_ops efi_rtc_ops = { 182 .read_time = efi_read_time, 183 .set_time = efi_set_time, 184 .read_alarm = efi_read_alarm, 185 .set_alarm = efi_set_alarm, 186 }; 187 188 static int __init efi_rtc_probe(struct platform_device *dev) 189 { 190 struct rtc_device *rtc; 191 192 rtc = rtc_device_register("rtc-efi", &dev->dev, &efi_rtc_ops, 193 THIS_MODULE); 194 if (IS_ERR(rtc)) 195 return PTR_ERR(rtc); 196 197 platform_set_drvdata(dev, rtc); 198 199 return 0; 200 } 201 202 static int __exit efi_rtc_remove(struct platform_device *dev) 203 { 204 struct rtc_device *rtc = platform_get_drvdata(dev); 205 206 rtc_device_unregister(rtc); 207 208 return 0; 209 } 210 211 static struct platform_driver efi_rtc_driver = { 212 .driver = { 213 .name = "rtc-efi", 214 .owner = THIS_MODULE, 215 }, 216 .remove = __exit_p(efi_rtc_remove), 217 }; 218 219 static int __init efi_rtc_init(void) 220 { 221 return platform_driver_probe(&efi_rtc_driver, efi_rtc_probe); 222 } 223 224 static void __exit efi_rtc_exit(void) 225 { 226 platform_driver_unregister(&efi_rtc_driver); 227 } 228 229 module_init(efi_rtc_init); 230 module_exit(efi_rtc_exit); 231 232 MODULE_AUTHOR("dann frazier <dannf@hp.com>"); 233 MODULE_LICENSE("GPL"); 234 MODULE_DESCRIPTION("EFI RTC driver"); 235