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-rw-r--r--drivers/rtc/rtc-efi.c292
1 files changed, 292 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
new file mode 100644
index 000000000..3454e7814
--- /dev/null
+++ b/drivers/rtc/rtc-efi.c
@@ -0,0 +1,292 @@
+/*
+ * 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
+ *
+ * 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)
+
+/*
+ * 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_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@dannf.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("EFI RTC driver");
+MODULE_ALIAS("platform:rtc-efi");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-03 00:33:51 +0000