apm.c

该文件是rt_linux

/* -*- linux-c -*-
 * APM BIOS driver for Linux
 * Copyright 1994-2001 Stephen Rothwell ([e-mail])
 *
 * Initial development of this driver was funded by NEC Australia P/L
 *	and NEC Corporation
 *
 * 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, or (at your option) any
 * later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * October 1995, Rik Faith ([e-mail]):
 *    Minor enhancements and updates (to the patch set) for 1.3.x
 *    Documentation
 * January 1996, Rik Faith ([e-mail]):
 *    Make /proc/apm easy to format (bump driver version)
 * March 1996, Rik Faith ([e-mail]):
 *    Prohibit APM BIOS calls unless apm_enabled.
 *    (Thanks to Ulrich Windl <[e-mail]>)
 * April 1996, Stephen Rothwell ([e-mail])
 *    Version 1.0 and 1.1
 * May 1996, Version 1.2
 * Feb 1998, Version 1.3
 * Feb 1998, Version 1.4
 * Aug 1998, Version 1.5
 * Sep 1998, Version 1.6
 * Nov 1998, Version 1.7
 * Jan 1999, Version 1.8
 * Jan 1999, Version 1.9
 * Oct 1999, Version 1.10
 * Nov 1999, Version 1.11
 * Jan 2000, Version 1.12
 * Feb 2000, Version 1.13
 * Nov 2000, Version 1.14
 * Oct 2001, Version 1.15
 * Jan 2002, Version 1.16
 *
 * History:
 *    0.6b: first version in official kernel, Linux 1.3.46
 *    0.7: changed /proc/apm format, Linux 1.3.58
 *    0.8: fixed gcc 2.7.[12] compilation problems, Linux 1.3.59
 *    0.9: only call bios if bios is present, Linux 1.3.72
 *    1.0: use fixed device number, consolidate /proc/apm into this file,
 *         Linux 1.3.85
 *    1.1: support user-space standby and suspend, power off after system
 *         halted, Linux 1.3.98
 *    1.2: When resetting RTC after resume, take care so that the time
 *         is only incorrect by 30-60mS (vs. 1S previously) (Gabor J. Toth
 *         <[e-mail]>); improve interaction between
 *         screen-blanking and gpm (Stephen Rothwell); Linux 1.99.4
 *    1.2a:Simple change to stop mysterious bug reports with SMP also added
 *	   levels to the printk calls. APM is not defined for SMP machines.
 *         The new replacment for it is, but Linux doesn't yet support this.
 *         Alan Cox Linux 2.1.55
 *    1.3: Set up a valid data descriptor 0x40 for buggy BIOS's
 *    1.4: Upgraded to support APM 1.2. Integrated ThinkPad suspend patch by
 *         Dean Gaudet <[e-mail]>.
 *         C. Scott Ananian <[e-mail]> Linux 2.1.87
 *    1.5: Fix segment register reloading (in case of bad segments saved
 *         across BIOS call).
 *         Stephen Rothwell
 *    1.6: Cope with complier/assembler differences.
 *         Only try to turn off the first display device.
 *         Fix OOPS at power off with no APM BIOS by Jan Echternach
 *                   <[e-mail]>
 *         Stephen Rothwell
 *    1.7: Modify driver's cached copy of the disabled/disengaged flags
 *         to reflect current state of APM BIOS.
 *         Chris Rankin <[e-mail]>
 *         Reset interrupt 0 timer to 100Hz after suspend
 *         Chad Miller <[e-mail]>
 *         Add CONFIG_APM_IGNORE_SUSPEND_BOUNCE
 *         Richard Gooch <[e-mail]>
 *         Allow boot time disabling of APM
 *         Make boot messages far less verbose by default
 *         Make asm safer
 *         Stephen Rothwell
 *    1.8: Add CONFIG_APM_RTC_IS_GMT
 *         Richard Gooch <[e-mail]>
 *         change APM_NOINTS to CONFIG_APM_ALLOW_INTS
 *         remove dependency on CONFIG_PROC_FS
 *         Stephen Rothwell
 *    1.9: Fix small typo.  <[e-mail]>
 *         Try to cope with BIOS's that need to have all display
 *         devices blanked and not just the first one.
 *         Ross Paterson <[e-mail]>
 *         Fix segment limit setting it has always been wrong as
 *         the segments needed to have byte granularity.
 *         Mark a few things __init.
 *         Add hack to allow power off of SMP systems by popular request.
 *         Use CONFIG_SMP instead of __SMP__
 *         Ignore BOUNCES for three seconds.
 *         Stephen Rothwell
 *   1.10: Fix for Thinkpad return code.
 *         Merge 2.2 and 2.3 drivers.
 *         Remove APM dependencies in arch/i386/kernel/process.c
 *         Remove APM dependencies in drivers/char/sysrq.c
 *         Reset time across standby.
 *         Allow more inititialisation on SMP.
 *         Remove CONFIG_APM_POWER_OFF and make it boot time
 *         configurable (default on).
 *         Make debug only a boot time parameter (remove APM_DEBUG).
 *         Try to blank all devices on any error.
 *   1.11: Remove APM dependencies in drivers/char/console.c
 *         Check nr_running to detect if we are idle (from
 *         Borislav Deianov <[e-mail]>)
 *         Fix for bioses that don't zero the top part of the
 *         entrypoint offset (Mario Sitta <[e-mail]>)
 *         (reported by Panos Katsaloulis <[e-mail]>).
 *         Real mode power off patch (Walter Hofmann
 *         <[e-mail]>).
 *   1.12: Remove CONFIG_SMP as the compiler will optimize
 *         the code away anyway (smp_num_cpus == 1 in UP)
 *         noted by Artur Skawina <[e-mail]>.
 *         Make power off under SMP work again.
 *         Fix thinko with initial engaging of BIOS.
 *         Make sure power off only happens on CPU 0
 *         (Paul "Rusty" Russell <[e-mail]>).
 *         Do error notification to user mode if BIOS calls fail.
 *         Move entrypoint offset fix to ...boot/setup.S
 *         where it belongs (Cosmos <[e-mail]>).
 *         Remove smp-power-off. SMP users must now specify
 *         "apm=power-off" on the kernel command line. Suggested
 *         by Jim Avera <[e-mail]>, modified by Alan Cox
 *         <[e-mail]>.
 *         Register the /proc/apm entry even on SMP so that
 *         scripts that check for it before doing power off
 *         work (Jim Avera <[e-mail]>).
 *   1.13: Changes for new pm_ interfaces (Andy Henroid
 *         <[e-mail]>).
 *         Modularize the code.
 *         Fix the Thinkpad (again) :-( (CONFIG_APM_IGNORE_MULTIPLE_SUSPENDS
 *         is now the way life works).
 *         Fix thinko in suspend() (wrong return).
 *         Notify drivers on critical suspend.
 *         Make kapmd absorb more idle time (Pavel Machek <[e-mail]>
 *         modified by sfr).
 *         Disable interrupts while we are suspended (Andy Henroid
 *         <[e-mail]> fixed by sfr).
 *         Make power off work on SMP again (Tony Hoyle
 *         <[e-mail]> and <[e-mail]>) modified by sfr.
 *         Remove CONFIG_APM_SUSPEND_BOUNCE.  The bounce ignore
 *         interval is now configurable.
 *   1.14: Make connection version persist across module unload/load.
 *         Enable and engage power management earlier.
 *         Disengage power management on module unload.
 *         Changed to use the sysrq-register hack for registering the
 *         power off function called by magic sysrq based upon discussions
 *         in irc://irc.openprojects.net/#kernelnewbies
 *         (Crutcher Dunnavant <[e-mail]>).
 *         Make CONFIG_APM_REAL_MODE_POWER_OFF run time configurable.
 *         (Arjan van de Ven <[e-mail]>) modified by sfr.
 *         Work around byte swap bug in one of the Vaio's BIOS's
 *         (Marc Boucher <[e-mail]>).
 *         Exposed the disable flag to dmi so that we can handle known
 *         broken APM (Alan Cox <[e-mail]>).
 *   1.14ac: If the BIOS says "I slowed the CPU down" then don't spin
 *         calling it - instead idle. (Alan Cox <[e-mail]>)
 *         If an APM idle fails log it and idle sensibly
 *   1.15: Don't queue events to clients who open the device O_WRONLY.
 *         Don't expect replies from clients who open the device O_RDONLY.
 *         (Idea from Thomas Hood <[e-mail]>)
 *         Minor waitqueue cleanups. (John Fremlin <[e-mail]>)
 *   1.16: Fix idle calling. (Andreas Steinmetz <[e-mail]> et al.)
 *         Notify listeners of standby or suspend events before notifying
 *         drivers. Return EBUSY to ioctl() if suspend is rejected.
 *         (Russell King <[e-mail]> and Thomas Hood)
 *         Ignore first resume after we generate our own resume event
 *         after a suspend (Thomas Hood <[e-mail]>)
 *         Daemonize now gets rid of our controlling terminal (sfr).
 *         CONFIG_APM_CPU_IDLE now just affects the default value of
 *         idle_threshold (sfr).
 *         Change name of kernel apm daemon (as it no longer idles) (sfr).
 *
 * APM 1.1 Reference:
 *
 *   Intel Corporation, Microsoft Corporation. Advanced Power Management
 *   (APM) BIOS Interface Specification, Revision 1.1, September 1993.
 *   Intel Order Number 241704-001.  Microsoft Part Number 781-110-X01.
 *
 * [This document is available free from Intel by calling 800.628.8686 (fax
 * 916.356.6100) or 800.548.4725; or via anonymous ftp from
 * ftp://ftp.intel.com/pub/IAL/software_specs/apmv11.doc.  It is also
 * available from Microsoft by calling 206.882.8080.]
 *
 * APM 1.2 Reference:
 *   Intel Corporation, Microsoft Corporation. Advanced Power Management
 *   (APM) BIOS Interface Specification, Revision 1.2, February 1996.
 *
 * [This document is available from Microsoft at:
 *    http://www.microsoft.com/hwdev/busbios/amp_12.htm]
 */

#include <linux/config.h>
#include <linux/module.h>

#include <linux/poll.h>
#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/timer.h>
#include <linux/fcntl.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/proc_fs.h>
#include <linux/miscdevice.h>
#include <linux/apm_bios.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/pm.h>
#include <linux/kernel.h>
#include <linux/smp_lock.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/desc.h>

#include <linux/sysrq.h>

extern unsigned long get_cmos_time(void);
extern void machine_real_restart(unsigned char *, int);

#if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
extern int (*console_blank_hook)(int);
#endif

/*
 * The apm_bios device is one of the misc char devices.
 * This is its minor number.
 */
#define	APM_MINOR_DEV	134

/*
 * See Documentation/Config.help for the configuration options.
 *
 * Various options can be changed at boot time as follows:
 * (We allow underscores for compatibility with the modules code)
 *	apm=on/off			enable/disable APM
 *	    [no-]allow[-_]ints		allow interrupts during BIOS calls
 *	    [no-]broken[-_]psr		BIOS has a broken GetPowerStatus call
 *	    [no-]realmode[-_]power[-_]off	switch to real mode before
 *	    					powering off
 *	    [no-]debug			log some debugging messages
 *	    [no-]power[-_]off		power off on shutdown
 *	    bounce[-_]interval=<n>	number of ticks to ignore suspend
 *	    				bounces
 *          idle[-_]threshold=<n>       System idle percentage above which to
 *                                      make APM BIOS idle calls. Set it to
 *                                      100 to disable.
 *          idle[-_]period=<n>          Period (in 1/100s of a second) over
 *                                      which the idle percentage is
 *                                      calculated.
 */

/* KNOWN PROBLEM MACHINES:
 *
 * U: TI 4000M TravelMate: BIOS is *NOT* APM compliant
 *                         [Confirmed by TI representative]
 * ?: ACER 486DX4/75: uses dseg 0040, in violation of APM specification
 *                    [Confirmed by BIOS disassembly]
 *                    [This may work now ...]
 * P: Toshiba 1950S: battery life information only gets updated after resume
 * P: Midwest Micro Soundbook Elite DX2/66 monochrome: screen blanking
 * 	broken in BIOS [Reported by Garst R. Reese <[e-mail]>]
 * ?: AcerNote-950: oops on reading /proc/apm - workaround is a WIP
 * 	Neale Banks <[e-mail]> December 2000
 *
 * Legend: U = unusable with APM patches
 *         P = partially usable with APM patches
 */

/*
 * Define as 1 to make the driver always call the APM BIOS busy
 * routine even if the clock was not reported as slowed by the
 * idle routine.  Otherwise, define as 0.
 */
#define ALWAYS_CALL_BUSY   1

/*
 * Define to make the APM BIOS calls zero all data segment registers (so
 * that an incorrect BIOS implementation will cause a kernel panic if it
 * tries to write to arbitrary memory).
 */
#define APM_ZERO_SEGS

/*
 * Define to make all _set_limit calls use 64k limits.  The APM 1.1 BIOS is
 * supposed to provide limit information that it recognizes.  Many machines
 * do this correctly, but many others do not restrict themselves to their
 * claimed limit.  When this happens, they will cause a segmentation
 * violation in the kernel at boot time.  Most BIOS's, however, will
 * respect a 64k limit, so we use that.  If you want to be pedantic and
 * hold your BIOS to its claims, then undefine this.
 */
#define APM_RELAX_SEGMENTS

/*
 * Define to re-initialize the interrupt 0 timer to 100 Hz after a suspend.
 * This patched by Chad Miller <[e-mail]>, original code by
 * David Chen <[e-mail]>
 */
#undef INIT_TIMER_AFTER_SUSPEND

#ifdef INIT_TIMER_AFTER_SUSPEND
#include <linux/timex.h>
#include <asm/io.h>
#include <linux/delay.h>
#endif

/*
 * Need to poll the APM BIOS every second
 */
#define APM_CHECK_TIMEOUT	(HZ)

/*
 * Ignore suspend events for this amount of time after a resume
 */
#define DEFAULT_BOUNCE_INTERVAL		(3 * HZ)

/*
 * Save a segment register away
 */
#define savesegment(seg, where) \
		__asm__ __volatile__("movl %%" #seg ",%0" : "=m" (where))

/*
 * Maximum number of events stored
 */
#define APM_MAX_EVENTS		20

/*
 * The per-file APM data
 */
struct apm_user {
	int		magic;
	struct apm_user *	next;
	int		suser: 1;
	int		writer: 1;
	int		reader: 1;
	int		suspend_wait: 1;
	int		suspend_result;
	int		suspends_pending;
	int		standbys_pending;
	int		suspends_read;
	int		standbys_read;
	int		event_head;
	int		event_tail;
	apm_event_t	events[APM_MAX_EVENTS];
};

/*
 * The magic number in apm_user
 */
#define APM_BIOS_MAGIC		0x4101

/*
 * idle percentage above which bios idle calls are done
 */
#ifdef CONFIG_APM_CPU_IDLE
#define DEFAULT_IDLE_THRESHOLD	95
#else
#define DEFAULT_IDLE_THRESHOLD	100
#endif
#define DEFAULT_IDLE_PERIOD	(100 / 3)

/*
 * Local variables
 */
static struct {
	unsigned long	offset;
	unsigned short	segment;
}				apm_bios_entry;
static int			clock_slowed;
static int			idle_threshold = DEFAULT_IDLE_THRESHOLD;
static int			idle_period = DEFAULT_IDLE_PERIOD;
static int			set_pm_idle;
static int			suspends_pending;
static int			standbys_pending;
static int			ignore_sys_suspend;
static int			ignore_normal_resume;
static int			bounce_interval = DEFAULT_BOUNCE_INTERVAL;

#ifdef CONFIG_APM_RTC_IS_GMT
#	define	clock_cmos_diff	0
#	define	got_clock_diff	1
#else
static long			clock_cmos_diff;
static int			got_clock_diff;
#endif
static int			debug;
static int			apm_disabled = -1;
#ifdef CONFIG_SMP
static int			power_off;
#else
static int			power_off = 1;
#endif
#ifdef CONFIG_APM_REAL_MODE_POWER_OFF
static int			realmode_power_off = 1;
#else
static int			realmode_power_off;
#endif
static int			exit_kapmd;
static int			kapmd_running;
#ifdef CONFIG_APM_ALLOW_INTS
static int			allow_ints = 1;
#else
static int			allow_ints;
#endif
static int			broken_psr;

static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
static struct apm_user *	user_list;

static char			driver_version[] = "1.16";	/* no spaces */

/*
 *	APM event names taken from the APM 1.2 specification. These are
 *	the message codes that the BIOS uses to tell us about events
 */
static char *	apm_event_name[] = {
	"system standby",
	"system suspend",
	"normal resume",
	"critical resume",
	"low battery",
	"power status change",
	"update time",
	"critical suspend",
	"user standby",
	"user suspend",
	"system standby resume",
	"capabilities change"
};
#define NR_APM_EVENT_NAME	\
		(sizeof(apm_event_name) / sizeof(apm_event_name[0]))

typedef struct lookup_t {
	int	key;
	char *	msg;
} lookup_t;

/*
 *	The BIOS returns a set of standard error codes in AX when the
 *	carry flag is set.
 */
 
static const lookup_t error_table[] = {
/* N/A	{ APM_SUCCESS,		"Operation succeeded" }, */
	{ APM_DISABLED,		"Power management disabled" },
	{ APM_CONNECTED,	"Real mode interface already connected" },
	{ APM_NOT_CONNECTED,	"Interface not connected" },
	{ APM_16_CONNECTED,	"16 bit interface already connected" },
/* N/A	{ APM_16_UNSUPPORTED,	"16 bit interface not supported" }, */
	{ APM_32_CONNECTED,	"32 bit interface already connected" },
	{ APM_32_UNSUPPORTED,	"32 bit interface not supported" },
	{ APM_BAD_DEVICE,	"Unrecognized device ID" },
	{ APM_BAD_PARAM,	"Parameter out of range" },
	{ APM_NOT_ENGAGED,	"Interface not engaged" },
	{ APM_BAD_FUNCTION,     "Function not supported" },
	{ APM_RESUME_DISABLED,	"Resume timer disabled" },
	{ APM_BAD_STATE,	"Unable to enter requested state" },
/* N/A	{ APM_NO_EVENTS,	"No events pending" }, */
	{ APM_NO_ERROR,		"BIOS did not set a return code" },
	{ APM_NOT_PRESENT,	"No APM present" }
};
#define ERROR_COUNT	(sizeof(error_table)/sizeof(lookup_t))

/**
 *	apm_error	-	display an APM error
 *	@str: information string
 *	@err: APM BIOS return code
 *
 *	Write a meaningful log entry to the kernel log in the event of
 *	an APM error.
 */
 
static void apm_error(char *str, int err)
{
	int	i;

	for (i = 0; i < ERROR_COUNT; i++)
		if (error_table[i].key == err) break;
	if (i < ERROR_COUNT)
		printk(KERN_NOTICE "apm: %s: %s\n", str, error_table[i].msg);
	else
		printk(KERN_NOTICE "apm: %s: unknown error code %#2.2x\n",
			str, err);
}

/*
 * These are the actual BIOS calls.  Depending on APM_ZERO_SEGS and
 * apm_info.allow_ints, we are being really paranoid here!  Not only
 * are interrupts disabled, but all the segment registers (except SS)
 * are saved and zeroed this means that if the BIOS tries to reference
 * any data without explicitly loading the segment registers, the kernel
 * will fault immediately rather than have some unforeseen circumstances
 * for the rest of the kernel.  And it will be very obvious!  :-) Doing
 * this depends on CS referring to the same physical memory as DS so that
 * DS can be zeroed before the call. Unfortunately, we can't do anything
 * about the stack segment/pointer.  Also, we tell the compiler that
 * everything could change.
 *