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>

arch/ia64/kernel/time.c

@@ -20,6 +20,7 @@
 #include <linux/efi.h>
 #include <linux/timex.h>
 #include <linux/clocksource.h>
+#include <linux/platform_device.h>
 
 #include <asm/machvec.h>
 #include <asm/delay.h>
@@ -405,6 +406,21 @@ static struct irqaction timer_irqaction = {
 	.name =		"timer"
 };
 
+static struct platform_device rtc_efi_dev = {
+	.name = "rtc-efi",
+	.id = -1,
+};
+
+static int __init rtc_init(void)
+{
+	if (platform_device_register(&rtc_efi_dev) < 0)
+		printk(KERN_ERR "unable to register rtc device...\n");
+
+	/* not necessarily an error */
+	return 0;
+}
+module_init(rtc_init);
+
 void __init
 time_init (void)
 {

drivers/rtc/Kconfig

@@ -440,6 +440,16 @@ config RTC_DRV_DS1742
 	  This driver can also be built as a module. If so, the module
 	  will be called rtc-ds1742.
 
+config RTC_DRV_EFI
+	tristate "EFI RTC"
+	depends on IA64
+	help
+	  If you say yes here you will get support for the EFI
+	  Real Time Clock.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-efi.
+
 config RTC_DRV_STK17TA8
 	tristate "Simtek STK17TA8"
 	depends on RTC_CLASS

drivers/rtc/Makefile

@@ -36,6 +36,7 @@ obj-$(CONFIG_RTC_DRV_DS1553)	+= rtc-ds1553.o
 obj-$(CONFIG_RTC_DRV_DS1672)	+= rtc-ds1672.o
 obj-$(CONFIG_RTC_DRV_DS1742)	+= rtc-ds1742.o
 obj-$(CONFIG_RTC_DRV_DS3234)	+= rtc-ds3234.o
+obj-$(CONFIG_RTC_DRV_EFI)	+= rtc-efi.o
 obj-$(CONFIG_RTC_DRV_EP93XX)	+= rtc-ep93xx.o
 obj-$(CONFIG_RTC_DRV_FM3130)	+= rtc-fm3130.o
 obj-$(CONFIG_RTC_DRV_ISL1208)	+= rtc-isl1208.o

drivers/rtc/rtc-efi.c

+/*
+ * 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");