// 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 int compute_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 int compute_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 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 bool convert_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_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; if (!convert_from_efi_time(&eft, &wkalrm->time)) return -EIO; 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; } 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, alm; efi_time_cap_t cap; efi_bool_t enabled, pending; memset(&eft, 0, sizeof(eft)); memset(&alm, 0, sizeof(alm)); memset(&cap, 0, sizeof(cap)); efi.get_time(&eft, &cap); efi.get_wakeup_time(&enabled, &pending, &alm); 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); seq_printf(seq, "Alarm Time\t: %u:%u:%u.%09u\n" "Alarm Date\t: %u-%u-%u\n" "Alarm Daylight\t: %u\n" "Enabled\t\t: %s\n" "Pending\t\t: %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(seq, "Timezone\t: unspecified\n"); else /* XXX fixme: convert to string? */ seq_printf(seq, "Timezone\t: %u\n", alm.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, .read_alarm = efi_read_alarm, .set_alarm = efi_set_alarm, .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_UPDATE_INTERRUPT, rtc->features); set_bit(RTC_FEATURE_ALARM_WAKEUP_ONLY, rtc->features); 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");