diff options
Diffstat (limited to 'drivers/rtc/rtc-efi.c')
| -rw-r--r-- | drivers/rtc/rtc-efi.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c new file mode 100644 index 000000000..cb989cd00 --- /dev/null +++ b/drivers/rtc/rtc-efi.c @@ -0,0 +1,239 @@ +/* + * 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/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) +/* + * EFI Epoch is 1/1/1998 + */ +#define EFI_RTC_EPOCH 1998 + +/* + * 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 + * + * Don't try to provide a year that's before 1998, please ! + */ +static int +compute_wday(efi_time_t *eft) +{ + int y; + int ndays = 0; + + if (eft->year < EFI_RTC_EPOCH) { + pr_err("EFI year < " __stringify(EFI_RTC_EPOCH) ", 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 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; + wtime->tm_year = eft->year - 1900; + + /* day of the week [0-6], Sunday=0 */ + wtime->tm_wday = compute_wday(eft); + if (wtime->tm_wday < 0) + return false; + + /* 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; + } + + 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 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); + + rtc->uie_unsupported = 1; + platform_set_drvdata(dev, rtc); + + return 0; +} + +static struct platform_driver efi_rtc_driver = { + .driver = { + .name = "rtc-efi", + }, +}; + +module_platform_driver_probe(efi_rtc_driver, efi_rtc_probe); + +MODULE_ALIAS("platform:rtc-efi"); +MODULE_AUTHOR("dann frazier <dannf@hp.com>"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("EFI RTC driver"); +MODULE_ALIAS("platform:rtc-efi"); |