[linux-2.6-block.git] / 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@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 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@dannf.org>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("EFI RTC driver");
MODULE_ALIAS("platform:rtc-efi");
Commit	Line	Data
5e3fd9e5	1	/*
	2	* rtc-efi: RTC Class Driver for EFI-based systems
	3	*
	4	* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
	5	*
37563e5e	6	* Author: dann frazier <dannf@dannf.org>
5e3fd9e5	7	* Based on efirtc.c by Stephane Eranian
	8	*
	9	* This program is free software; you can redistribute it and/or modify it
	10	* under the terms of the GNU General Public License as published by the
	11	* Free Software Foundation; either version 2 of the License, or (at your
	12	* option) any later version.
	13	*
	14	*/
	15
34650f9e JH	16	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34650f9e JH	17
5e3fd9e5	18	#include <linux/kernel.h>
5e3fd9e5	19	#include <linux/module.h>
6e85bab6	20	#include <linux/stringify.h>
5e3fd9e5	21	#include <linux/time.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/rtc.h>
	24	#include <linux/efi.h>
	25
	26	#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT\|EFI_TIME_IN_DAYLIGHT)
5e3fd9e5	27
	28	/*
	29	* returns day of the year [0-365]
	30	*/
	31	static inline int
	32	compute_yday(efi_time_t *eft)
	33	{
	34	/* efi_time_t.month is in the [1-12] so, we need -1 */
809d9627	35	return rtc_year_days(eft->day, eft->month - 1, eft->year);
5e3fd9e5	36	}
b2bd2370	37
5e3fd9e5	38	/*
5e3fd9e5	39	* returns day of the week [0-6] 0=Sunday
5e3fd9e5	40	*/
5e3fd9e5	41	static int
b2bd2370	42	compute_wday(efi_time_t *eft, int yday)
5e3fd9e5	43	{
b2bd2370 AB	44	int ndays = eft->year * (365 % 7)
	45	+ (eft->year - 1) / 4
	46	- (eft->year - 1) / 100
	47	+ (eft->year - 1) / 400
	48	+ yday;
5e3fd9e5	49
5e3fd9e5	50	/*
b2bd2370 AB	51	* 1/1/0000 may or may not have been a Sunday (if it ever existed at
b2bd2370 AB	52	* all) but assuming it was makes this calculation work correctly.
5e3fd9e5	53	*/
b2bd2370	54	return ndays % 7;
5e3fd9e5	55	}
	56
	57	static void
	58	convert_to_efi_time(struct rtc_time wtime, efi_time_t eft)
	59	{
	60	eft->year = wtime->tm_year + 1900;
	61	eft->month = wtime->tm_mon + 1;
	62	eft->day = wtime->tm_mday;
	63	eft->hour = wtime->tm_hour;
	64	eft->minute = wtime->tm_min;
34650f9e	65	eft->second = wtime->tm_sec;
5e3fd9e5	66	eft->nanosecond = 0;
	67	eft->daylight = wtime->tm_isdst ? EFI_ISDST : 0;
	68	eft->timezone = EFI_UNSPECIFIED_TIMEZONE;
	69	}
	70
6e85bab6	71	static bool
5e3fd9e5	72	convert_from_efi_time(efi_time_t eft, struct rtc_time wtime)
	73	{
	74	memset(wtime, 0, sizeof(*wtime));
6e85bab6 JB	75
	76	if (eft->second >= 60)
	77	return false;
5e3fd9e5	78	wtime->tm_sec = eft->second;
6e85bab6 JB	79
	80	if (eft->minute >= 60)
	81	return false;
5e3fd9e5	82	wtime->tm_min = eft->minute;
6e85bab6 JB	83
	84	if (eft->hour >= 24)
	85	return false;
5e3fd9e5	86	wtime->tm_hour = eft->hour;
6e85bab6 JB	87
	88	if (!eft->day \|\| eft->day > 31)
	89	return false;
5e3fd9e5	90	wtime->tm_mday = eft->day;
6e85bab6 JB	91
	92	if (!eft->month \|\| eft->month > 12)
	93	return false;
5e3fd9e5	94	wtime->tm_mon = eft->month - 1;
5e3fd9e5	95
b2bd2370	96	if (eft->year < 1900 \|\| eft->year > 9999)
6e85bab6	97	return false;
b2bd2370	98	wtime->tm_year = eft->year - 1900;
5e3fd9e5	99
	100	/* day in the year [1-365]*/
	101	wtime->tm_yday = compute_yday(eft);
	102
b2bd2370 AB	103	/* day of the week [0-6], Sunday=0 */
b2bd2370 AB	104	wtime->tm_wday = compute_wday(eft, wtime->tm_yday);
5e3fd9e5	105
	106	switch (eft->daylight & EFI_ISDST) {
	107	case EFI_ISDST:
	108	wtime->tm_isdst = 1;
	109	break;
	110	case EFI_TIME_ADJUST_DAYLIGHT:
	111	wtime->tm_isdst = 0;
	112	break;
	113	default:
	114	wtime->tm_isdst = -1;
	115	}
6e85bab6 JB	116
6e85bab6 JB	117	return true;
5e3fd9e5	118	}
	119
	120	static int efi_read_alarm(struct device dev, struct rtc_wkalrm wkalrm)
	121	{
	122	efi_time_t eft;
	123	efi_status_t status;
	124
	125	/*
	126	* As of EFI v1.10, this call always returns an unsupported status
	127	*/
	128	status = efi.get_wakeup_time((efi_bool_t *)&wkalrm->enabled,
	129	(efi_bool_t *)&wkalrm->pending, &eft);
	130
	131	if (status != EFI_SUCCESS)
	132	return -EINVAL;
	133
6e85bab6 JB	134	if (!convert_from_efi_time(&eft, &wkalrm->time))
6e85bab6 JB	135	return -EIO;
5e3fd9e5	136
	137	return rtc_valid_tm(&wkalrm->time);
	138	}
	139
	140	static int efi_set_alarm(struct device dev, struct rtc_wkalrm wkalrm)
	141	{
	142	efi_time_t eft;
	143	efi_status_t status;
	144
	145	convert_to_efi_time(&wkalrm->time, &eft);
	146
	147	/*
	148	* XXX Fixme:
	149	* As of EFI 0.92 with the firmware I have on my
	150	* machine this call does not seem to work quite
	151	* right
	152	*
	153	* As of v1.10, this call always returns an unsupported status
	154	*/
	155	status = efi.set_wakeup_time((efi_bool_t)wkalrm->enabled, &eft);
	156
34650f9e	157	dev_warn(dev, "write status is %d\n", (int)status);
5e3fd9e5	158
	159	return status == EFI_SUCCESS ? 0 : -EINVAL;
	160	}
	161
	162	static int efi_read_time(struct device dev, struct rtc_time tm)
	163	{
	164	efi_status_t status;
	165	efi_time_t eft;
	166	efi_time_cap_t cap;
	167
	168	status = efi.get_time(&eft, &cap);
	169
	170	if (status != EFI_SUCCESS) {
	171	/* should never happen */
34650f9e	172	dev_err(dev, "can't read time\n");
5e3fd9e5	173	return -EINVAL;
	174	}
	175
6e85bab6 JB	176	if (!convert_from_efi_time(&eft, tm))
6e85bab6 JB	177	return -EIO;
5e3fd9e5	178
	179	return rtc_valid_tm(tm);
	180	}
	181
	182	static int efi_set_time(struct device dev, struct rtc_time tm)
	183	{
	184	efi_status_t status;
	185	efi_time_t eft;
	186
	187	convert_to_efi_time(tm, &eft);
	188
	189	status = efi.set_time(&eft);
	190
	191	return status == EFI_SUCCESS ? 0 : -EINVAL;
	192	}
	193
	194	static const struct rtc_class_ops efi_rtc_ops = {
	195	.read_time = efi_read_time,
	196	.set_time = efi_set_time,
	197	.read_alarm = efi_read_alarm,
	198	.set_alarm = efi_set_alarm,
	199	};
	200
	201	static int __init efi_rtc_probe(struct platform_device *dev)
	202	{
	203	struct rtc_device *rtc;
	204
6ae15b0e	205	rtc = devm_rtc_device_register(&dev->dev, "rtc-efi", &efi_rtc_ops,
5e3fd9e5	206	THIS_MODULE);
	207	if (IS_ERR(rtc))
	208	return PTR_ERR(rtc);
	209
822a0279	210	rtc->uie_unsupported = 1;
5e3fd9e5	211	platform_set_drvdata(dev, rtc);
	212
	213	return 0;
	214	}
	215
5e3fd9e5	216	static struct platform_driver efi_rtc_driver = {
	217	.driver = {
	218	.name = "rtc-efi",
5e3fd9e5	219	},
5e3fd9e5	220	};
5e3fd9e5	221
52c6ecbc	222	module_platform_driver_probe(efi_rtc_driver, efi_rtc_probe);
5e3fd9e5	223
451ff6d4	224	MODULE_ALIAS("platform:rtc-efi");
37563e5e	225	MODULE_AUTHOR("dann frazier <dannf@dannf.org>");
5e3fd9e5	226	MODULE_LICENSE("GPL");
5e3fd9e5	227	MODULE_DESCRIPTION("EFI RTC driver");
3f71f6da	228	MODULE_ALIAS("platform:rtc-efi");