rtc: add platform driver for EFI
Munge Stephane Eranian's efirtc.c code into an rtc platform driver
[akpm@linux-foundation.org: use is_leap_year()]
Signed-off-by: dann frazier <dannf@hp.com>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Cc: stephane eranian <eranian@googlemail.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
new file mode 100644
index 0000000..5502923
--- /dev/null
+++ b/drivers/rtc/rtc-efi.c
@@ -0,0 +1,235 @@
+/*
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.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 - 1, 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 < 1998) {
+ printk(KERN_ERR "efirtc: EFI year < 1998, 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 void
+convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
+{
+ memset(wtime, 0, sizeof(*wtime));
+ wtime->tm_sec = eft->second;
+ wtime->tm_min = eft->minute;
+ wtime->tm_hour = eft->hour;
+ wtime->tm_mday = eft->day;
+ 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);
+
+ /* 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;
+ }
+}
+
+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;
+
+ convert_from_efi_time(&eft, &wkalrm->time);
+
+ 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);
+
+ printk(KERN_WARNING "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 */
+ printk(KERN_ERR "efitime: can't read time\n");
+ return -EINVAL;
+ }
+
+ convert_from_efi_time(&eft, tm);
+
+ 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 = rtc_device_register("rtc-efi", &dev->dev, &efi_rtc_ops,
+ THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ platform_set_drvdata(dev, rtc);
+
+ return 0;
+}
+
+static int __exit efi_rtc_remove(struct platform_device *dev)
+{
+ struct rtc_device *rtc = platform_get_drvdata(dev);
+
+ rtc_device_unregister(rtc);
+
+ return 0;
+}
+
+static struct platform_driver efi_rtc_driver = {
+ .driver = {
+ .name = "rtc-efi",
+ .owner = THIS_MODULE,
+ },
+ .probe = efi_rtc_probe,
+ .remove = __exit_p(efi_rtc_remove),
+};
+
+static int __init efi_rtc_init(void)
+{
+ return platform_driver_probe(&efi_rtc_driver, efi_rtc_probe);
+}
+
+static void __exit efi_rtc_exit(void)
+{
+ platform_driver_unregister(&efi_rtc_driver);
+}
+
+module_init(efi_rtc_init);
+module_exit(efi_rtc_exit);
+
+MODULE_AUTHOR("dann frazier <dannf@hp.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("EFI RTC driver");
