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linux-next/include/linux/mc146818rtc.h
David Brownell 87ac84f42a rtc-cmos wakeup interface 
I finally got around to testing the updated wakeup event hooks for rtc-cmos,
and they follow in two patches:

 - Interface update ... when a simple enable_irq_wake() doesn't suffice,
   the platform data can hold suspend/resume callback hooks.

 - ACPI implementation ... provides callback hooks to do ACPI magic, and
   eliminate the legacy /proc/acpi/alarm file.

The interface update could go into 2.6.21, but that's not essential; they
will be NOPs on most PCs, without the ACPI stuff.

I suspect the ACPI folk may have opinions about how to merge that second
patch, and how to obsolete that legacy procfs file.  I'd like to see that
merge into 2.6.22 if possible...

As for how to kick it in ... two ways:

 - The appended "rtcwake" program; updated since the last time it was
   posted, it deals much better with timezones and DST.

 - Write the /sys/class/rtc/.../wakealarm file, then go to sleep.

For some reason RTC wake from "swsusp" stopped working on a system where
it previously worked; the alarm setting appears to get clobbered.  But
on the bright side, RTC wake from "standby" worked on a system that had
never been able to resume from that state before ... IDEACPI is my guess
as to why it finally started to work.  It's the old "two steps forward,
one step back" dance, I guess.

- Dave

/* gcc -Wall -Os -o rtcwake rtcwake.c */

#include <stdio.h>
#include <getopt.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>

#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/types.h>

#include <linux/rtc.h>

/* constants from legacy PC/AT hardware */
#define	RTC_PF	0x40
#define	RTC_AF	0x20
#define	RTC_UF	0x10

/*
 * rtcwake -- enter a system sleep state until specified wakeup time.
 *
 * This uses cross-platform Linux interfaces to enter a system sleep state,
 * and leave it no later than a specified time.  It uses any RTC framework
 * driver that supports standard driver model wakeup flags.
 *
 * This is normally used like the old "apmsleep" utility, to wake from a
 * suspend state like ACPI S1 (standby) or S3 (suspend-to-RAM).  Most
 * platforms can implement those without analogues of BIOS, APM, or ACPI.
 *
 * On some systems, this can also be used like "nvram-wakeup", waking
 * from states like ACPI S4 (suspend to disk).  Not all systems have
 * persistent media that are appropriate for such suspend modes.
 *
 * The best way to set the system's RTC is so that it holds the current
 * time in UTC.  Use the "-l" flag to tell this program that the system
 * RTC uses a local timezone instead (maybe you dual-boot MS-Windows).
 */

static char		*progname;

#ifdef	DEBUG
#define	VERSION	"1.0 dev (" __DATE__ " " __TIME__ ")"
#else
#define	VERSION	"0.9"
#endif

static unsigned		verbose;
static int		rtc_is_utc = -1;

static int may_wakeup(const char *devname)
{
	char	buf[128], *s;
	FILE	*f;

	snprintf(buf, sizeof buf, "/sys/class/rtc/%s/device/power/wakeup",
			devname);
	f = fopen(buf, "r");
	if (!f) {
		perror(buf);
		return 0;
	}
	fgets(buf, sizeof buf, f);
	fclose(f);

	s = strchr(buf, '\n');
	if (!s)
		return 0;
	*s = 0;

	/* wakeup events could be disabled or not supported */
	return strcmp(buf, "enabled") == 0;
}

/* all times should be in UTC */
static time_t	sys_time;
static time_t	rtc_time;

static int get_basetimes(int fd)
{
	struct tm	tm;
	struct rtc_time	rtc;

	/* this process works in RTC time, except when working
	 * with the system clock (which always uses UTC).
	 */
	if (rtc_is_utc)
		setenv("TZ", "UTC", 1);
	tzset();

	/* read rtc and system clocks "at the same time", or as
	 * precisely (+/- a second) as we can read them.
	 */
	if (ioctl(fd, RTC_RD_TIME, &rtc) < 0) {
		perror("read rtc time");
		return 0;
	}
	sys_time = time(0);
	if (sys_time == (time_t)-1) {
		perror("read system time");
		return 0;
	}

	/* convert rtc_time to normal arithmetic-friendly form,
	 * updating tm.tm_wday as used by asctime().
	 */
	memset(&tm, 0, sizeof tm);
	tm.tm_sec = rtc.tm_sec;
	tm.tm_min = rtc.tm_min;
	tm.tm_hour = rtc.tm_hour;
	tm.tm_mday = rtc.tm_mday;
	tm.tm_mon = rtc.tm_mon;
	tm.tm_year = rtc.tm_year;
	tm.tm_isdst = rtc.tm_isdst;	/* stays unspecified? */
	rtc_time = mktime(&tm);

	if (rtc_time == (time_t)-1) {
		perror("convert rtc time");
		return 0;
	}

	if (verbose) {
		if (!rtc_is_utc) {
			printf("\ttzone   = %ld\n", timezone);
			printf("\ttzname  = %s\n", tzname[daylight]);
			gmtime_r(&rtc_time, &tm);
		}
		printf("\tsystime = %ld, (UTC) %s",
				(long) sys_time, asctime(gmtime(&sys_time)));
		printf("\trtctime = %ld, (UTC) %s",
				(long) rtc_time, asctime(&tm));
	}

	return 1;
}

static int setup_alarm(int fd, time_t *wakeup)
{
	struct tm		*tm;
	struct rtc_wkalrm	wake;

	tm = gmtime(wakeup);

	wake.time.tm_sec = tm->tm_sec;
	wake.time.tm_min = tm->tm_min;
	wake.time.tm_hour = tm->tm_hour;
	wake.time.tm_mday = tm->tm_mday;
	wake.time.tm_mon = tm->tm_mon;
	wake.time.tm_year = tm->tm_year;
	wake.time.tm_wday = tm->tm_wday;
	wake.time.tm_yday = tm->tm_yday;
	wake.time.tm_isdst = tm->tm_isdst;

	/* many rtc alarms only support up to 24 hours from 'now' ... */
	if ((rtc_time + (24 * 60 * 60)) > *wakeup) {
		if (ioctl(fd, RTC_ALM_SET, &wake.time) < 0) {
			perror("set rtc alarm");
			return 0;
		}
		if (ioctl(fd, RTC_AIE_ON, 0) < 0) {
			perror("enable rtc alarm");
			return 0;
		}

	/* ... so use the "more than 24 hours" request only if we must */
	} else {
		/* avoid an extra AIE_ON call */
		wake.enabled = 1;

		if (ioctl(fd, RTC_WKALM_SET, &wake) < 0) {
			perror("set rtc wake alarm");
			return 0;
		}
	}

	return 1;
}

static void suspend_system(const char *suspend)
{
	FILE	*f = fopen("/sys/power/state", "w");

	if (!f) {
		perror("/sys/power/state");
		return;
	}

	fprintf(f, "%s\n", suspend);
	fflush(f);

	/* this executes after wake from suspend */
	fclose(f);
}

int main(int argc, char **argv)
{
	static char		*devname = "rtc0";
	static unsigned		seconds = 0;
	static char		*suspend = "standby";

	int		t;
	int		fd;
	time_t		alarm = 0;

	progname = strrchr(argv[0], '/');
	if (progname)
		progname++;
	else
		progname = argv[0];
	if (chdir("/dev/") < 0) {
		perror("chdir /dev");
		return 1;
	}

	while ((t = getopt(argc, argv, "d:lm:s:t:uVv")) != EOF) {
		switch (t) {

		case 'd':
			devname = optarg;
			break;

		case 'l':
			rtc_is_utc = 0;
			break;

		/* what system power mode to use?  for now handle only
		 * standardized mode names; eventually when systems define
		 * their own state names, parse /sys/power/state.
		 *
		 * "on" is used just to test the RTC alarm mechanism,
		 * bypassing all the wakeup-from-sleep infrastructure.
		 */
		case 'm':
			if (strcmp(optarg, "standby") == 0
					|| strcmp(optarg, "mem") == 0
					|| strcmp(optarg, "disk") == 0
					|| strcmp(optarg, "on") == 0
					) {
				suspend = optarg;
				break;
			}
			printf("%s: unrecognized suspend state '%s'\n",
					progname, optarg);
			goto usage;

		/* alarm time, seconds-to-sleep (relative) */
		case 's':
			t = atoi(optarg);
			if (t < 0) {
				printf("%s: illegal interval %s seconds\n",
						progname, optarg);
				goto usage;
			}
			seconds = t;
			break;

		/* alarm time, time_t (absolute, seconds since 1/1 1970 UTC) */
		case 't':
			t = atoi(optarg);
			if (t < 0) {
				printf("%s: illegal time_t value %s\n",
						progname, optarg);
				goto usage;
			}
			alarm = t;
			break;

		case 'u':
			rtc_is_utc = 1;
			break;

		case 'v':
			verbose++;
			break;

		case 'V':
			printf("%s: version %s\n", progname, VERSION);
			break;

		default:
usage:
			printf("usage: %s [options]"
				"\n\t"
				"-d rtc0|rtc1|...\t(select rtc)"
				"\n\t"
				"-l\t\t\t(RTC uses local timezone)"
				"\n\t"
				"-m standby|mem|...\t(sleep mode)"
				"\n\t"
				"-s seconds\t\t(seconds to sleep)"
				"\n\t"
				"-t time_t\t\t(time to wake)"
				"\n\t"
				"-u\t\t\t(RTC uses UTC)"
				"\n\t"
				"-v\t\t\t(verbose messages)"
				"\n\t"
				"-V\t\t\t(show version)"
				"\n",
				progname);
			return 1;
		}
	}

	if (!alarm && !seconds) {
		printf("%s: must provide wake time\n", progname);
		goto usage;
	}

	/* REVISIT:  if /etc/adjtime exists, read it to see what
	 * the util-linux version of hwclock assumes.
	 */
	if (rtc_is_utc == -1) {
		printf("%s: assuming RTC uses UTC ...\n", progname);
		rtc_is_utc = 1;
	}

	/* this RTC must exist and (if we'll sleep) be wakeup-enabled */
	fd = open(devname, O_RDONLY);
	if (fd < 0) {
		perror(devname);
		return 1;
	}
	if (strcmp(suspend, "on") != 0 && !may_wakeup(devname)) {
		printf("%s: %s not enabled for wakeup events\n",
				progname, devname);
		return 1;
	}

	/* relative or absolute alarm time, normalized to time_t */
	if (!get_basetimes(fd))
		return 1;
	if (verbose)
		printf("alarm %ld, sys_time %ld, rtc_time %ld, seconds %u\n",
				alarm, sys_time, rtc_time, seconds);
	if (alarm) {
		if (alarm < sys_time) {
			printf("%s: time doesn't go backward to %s",
					progname, ctime(&alarm));
			return 1;
		}
		alarm += sys_time - rtc_time;
	} else
		alarm = rtc_time + seconds + 1;
	if (setup_alarm(fd, &alarm) < 0)
		return 1;

	sync();
	printf("%s: wakeup from \"%s\" using %s at %s",
			progname, suspend, devname,
			ctime(&alarm));
	fflush(stdout);
	usleep(10 * 1000);

	if (strcmp(suspend, "on") != 0)
		suspend_system(suspend);
	else {
		unsigned long data;

		do {
			t = read(fd, &data, sizeof data);
			if (t < 0) {
				perror("rtc read");
				break;
			}
			if (verbose)
				printf("... %s: %03lx\n", devname, data);
		} while (!(data & RTC_AF));
	}

	if (ioctl(fd, RTC_AIE_OFF, 0) < 0)
		perror("disable rtc alarm interrupt");

	close(fd);
	return 0;
}

This patch:

Make rtc-cmos do the relevant magic so this RTC can wake the system from a
sleep state.  That magic comes in two basic flavors:

 - Straightforward:  enable_irq_wake(), the way it'd work on most SOC chips;
   or generally with system sleep states which don't disable core IRQ logic.

 - Roundabout, using non-IRQ platform hooks.  This is needed with ACPI and
   one almost-clone chip which uses a special wakeup-only alarm.  (That's
   the RTC used on Footbridge boards, FWIW, which don't do PM in Linux.)

A separate patch implements those hooks for ACPI platforms, so that rtc_cmos
can issue system wakeup events (and its sysfs "wakealarm" attribute works on
at least some systems).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:18 -07:00

117 lines
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/* mc146818rtc.h - register definitions for the Real-Time-Clock / CMOS RAM
* Copyright Torsten Duwe <duwe@informatik.uni-erlangen.de> 1993
* derived from Data Sheet, Copyright Motorola 1984 (!).
* It was written to be part of the Linux operating system.
*/
/* permission is hereby granted to copy, modify and redistribute this code
* in terms of the GNU Library General Public License, Version 2 or later,
* at your option.
*/
#ifndef _MC146818RTC_H
#define _MC146818RTC_H
#include <asm/io.h>
#include <linux/rtc.h> /* get the user-level API */
#include <asm/mc146818rtc.h> /* register access macros */
#ifdef __KERNEL__
#include <linux/spinlock.h> /* spinlock_t */
extern spinlock_t rtc_lock; /* serialize CMOS RAM access */
/* Some RTCs extend the mc146818 register set to support alarms of more
* than 24 hours in the future; or dates that include a century code.
* This platform_data structure can pass this information to the driver.
*
* Also, some platforms need suspend()/resume() hooks to kick in special
* handling of wake alarms, e.g. activating ACPI BIOS hooks or setting up
* a separate wakeup alarm used by some almost-clone chips.
*/
struct cmos_rtc_board_info {
void (*wake_on)(struct device *dev);
void (*wake_off)(struct device *dev);
u8 rtc_day_alarm; /* zero, or register index */
u8 rtc_mon_alarm; /* zero, or register index */
u8 rtc_century; /* zero, or register index */
};
#endif
/**********************************************************************
* register summary
**********************************************************************/
#define RTC_SECONDS 0
#define RTC_SECONDS_ALARM 1
#define RTC_MINUTES 2
#define RTC_MINUTES_ALARM 3
#define RTC_HOURS 4
#define RTC_HOURS_ALARM 5
/* RTC_*_alarm is always true if 2 MSBs are set */
# define RTC_ALARM_DONT_CARE 0xC0
#define RTC_DAY_OF_WEEK 6
#define RTC_DAY_OF_MONTH 7
#define RTC_MONTH 8
#define RTC_YEAR 9
/* control registers - Moto names
*/
#define RTC_REG_A 10
#define RTC_REG_B 11
#define RTC_REG_C 12
#define RTC_REG_D 13
/**********************************************************************
* register details
**********************************************************************/
#define RTC_FREQ_SELECT RTC_REG_A
/* update-in-progress - set to "1" 244 microsecs before RTC goes off the bus,
* reset after update (may take 1.984ms @ 32768Hz RefClock) is complete,
* totalling to a max high interval of 2.228 ms.
*/
# define RTC_UIP 0x80
# define RTC_DIV_CTL 0x70
/* divider control: refclock values 4.194 / 1.049 MHz / 32.768 kHz */
# define RTC_REF_CLCK_4MHZ 0x00
# define RTC_REF_CLCK_1MHZ 0x10
# define RTC_REF_CLCK_32KHZ 0x20
/* 2 values for divider stage reset, others for "testing purposes only" */
# define RTC_DIV_RESET1 0x60
# define RTC_DIV_RESET2 0x70
/* Periodic intr. / Square wave rate select. 0=none, 1=32.8kHz,... 15=2Hz */
# define RTC_RATE_SELECT 0x0F
/**********************************************************************/
#define RTC_CONTROL RTC_REG_B
# define RTC_SET 0x80 /* disable updates for clock setting */
# define RTC_PIE 0x40 /* periodic interrupt enable */
# define RTC_AIE 0x20 /* alarm interrupt enable */
# define RTC_UIE 0x10 /* update-finished interrupt enable */
# define RTC_SQWE 0x08 /* enable square-wave output */
# define RTC_DM_BINARY 0x04 /* all time/date values are BCD if clear */
# define RTC_24H 0x02 /* 24 hour mode - else hours bit 7 means pm */
# define RTC_DST_EN 0x01 /* auto switch DST - works f. USA only */
/**********************************************************************/
#define RTC_INTR_FLAGS RTC_REG_C
/* caution - cleared by read */
# define RTC_IRQF 0x80 /* any of the following 3 is active */
# define RTC_PF 0x40
# define RTC_AF 0x20
# define RTC_UF 0x10
/**********************************************************************/
#define RTC_VALID RTC_REG_D
# define RTC_VRT 0x80 /* valid RAM and time */
/**********************************************************************/
#ifndef ARCH_RTC_LOCATION /* Override by <asm/mc146818rtc.h>? */
#define RTC_IO_EXTENT 0x8
#define RTC_IOMAPPED 1 /* Default to I/O mapping. */
#endif /* ARCH_RTC_LOCATION */
#endif /* _MC146818RTC_H */
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