apm.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#include <u.h>
#include <libc.h>
#include </386/include/ureg.h>
typedef struct Ureg Ureg;
#include <auth.h>
#include <fcall.h>
#include <thread.h>
#include <9p.h>

enum {
	/* power mgmt event codes */
	NotifyStandbyRequest		= 0x0001,
	NotifySuspendRequest		= 0x0002,
	NotifyNormalResume 		= 0x0003,
	NotifyCriticalResume		= 0x0004,
	NotifyBatteryLow			= 0x0005,
	NotifyPowerStatusChange	= 0x0006,
	NotifyUpdateTime			= 0x0007,
	NotifyCriticalSuspend		= 0x0008,
	NotifyUserStandbyRequest	= 0x0009,
	NotifyUserSuspendRequest	= 0x000A,
	NotifyStandbyResume		= 0x000B,
	NotifyCapabilitiesChange		= 0x000C,

	/* power device ids: add device number or All */
	DevBios					= 0x0000,
	DevAll					= 0x0001,
	DevDisplay				= 0x0100,
	DevStorage				= 0x0200,
	DevLpt					= 0x0300,
	DevEia					= 0x0400,
	DevNetwork				= 0x0500,
	DevPCMCIA				= 0x0600,
	DevBattery				= 0x8000,
		All					= 0x00FF,
	DevMask					= 0xFF00,

	/* power states */
	PowerEnabled				= 0x0000,
	PowerStandby				= 0x0001,
	PowerSuspend				= 0x0002,
	PowerOff					= 0x0003,

	/* apm commands */
	CmdInstallationCheck		= 0x5300,
	CmdRealModeConnect		= 0x5301,
	CmdProtMode16Connect		= 0x5302,
	CmdProtMode32Connect		= 0x5303,
	CmdDisconnect			= 0x5304,
	CmdCpuIdle				= 0x5305,
	CmdCpuBusy				= 0x5306,
	CmdSetPowerState			= 0x5307,
	CmdSetPowerMgmt	= 0x5308,
	  DisablePowerMgmt	= 0x0000,		/* CX */
	  EnablePowerMgmt	= 0x0001,
	CmdRestoreDefaults			= 0x5309,
	CmdGetPowerStatus			= 0x530A,
	CmdGetPMEvent			= 0x530B,
	CmdGetPowerState			= 0x530C,
	CmdGetPowerMgmt			= 0x530D,
	CmdDriverVersion			= 0x530E,

	/* like CmdDisconnect but doesn't lose the interface */
	CmdGagePowerMgmt	= 0x530F,
	  DisengagePowerMgmt	= 0x0000,	/* CX */
	  EngagePowerManagemenet	= 0x0001,

	CmdGetCapabilities			= 0x5310,
	  CapStandby				= 0x0001,
	  CapSuspend				= 0x0002,
	  CapTimerResumeStandby	= 0x0004,
	  CapTimerResumeSuspend	= 0x0008,
	  CapRingResumeStandby		= 0x0010,
	  CapRingResumeSuspend	= 0x0020,
	  CapPcmciaResumeStandby	= 0x0040,
	  CapPcmciaResumeSuspend	= 0x0080,
	  CapSlowCpu				= 0x0100,
	CmdResumeTimer			= 0x5311,
	  DisableResumeTimer		= 0x00,		/* CL */
	  GetResumeTimer			= 0x01,
	  SetResumeTimer			= 0x02,
	CmdResumeOnRing			= 0x5312,
	  DisableResumeOnRing		= 0x0000,		/* CX */
	  EnableResumeOnRing		= 0x0001,
	  GetResumeOnRing			= 0x0002,
	CmdTimerRequests			= 0x5313,
	  DisableTimerRequests		= 0x0000,		/* CX */
	  EnableTimerRequests		= 0x0001,
	  GetTimerRequests			= 0x0002,
};

static char* eventstr[] = {
[NotifyStandbyRequest]	"system standby request",
[NotifySuspendRequest]	"system suspend request",
[NotifyNormalResume]	"normal resume",
[NotifyCriticalResume]	"critical resume",
[NotifyBatteryLow]		"battery low",
[NotifyPowerStatusChange]	"power status change",
[NotifyUpdateTime]		"update time",
[NotifyCriticalSuspend]	"critical suspend",
[NotifyUserStandbyRequest]	"user standby request",
[NotifyUserSuspendRequest]	"user suspend request",
[NotifyCapabilitiesChange]	"capabilities change",
};

static char*
apmevent(int e)
{
	static char buf[32];

	if(0 <= e && e < nelem(eventstr) && eventstr[e])
		return eventstr[e];
	
	sprint(buf, "event 0x%ux", (uint)e);
	return buf;
}

static char *error[256] = {
[0x01]	"power mgmt disabled",
[0x02]	"real mode connection already established",
[0x03]	"interface not connected",
[0x05]	"16-bit protected mode connection already established",
[0x06]	"16-bit protected mode interface not supported",
[0x07]	"32-bit protected mode interface already established",
[0x08]	"32-bit protected mode interface not supported",
[0x09]	"unrecognized device id",
[0x0A]	"parameter value out of range",
[0x0B]	"interface not engaged",
[0x0C]	"function not supported",
[0x0D]	"resume timer disabled",
[0x60]	"unable to enter requested state",
[0x80]	"no power mgmt events pending",
[0x86]	"apm not present",
};

static char*
apmerror(int id)
{
	char *e;
	static char buf[64];

	if(e = error[id&0xFF])
		return e;

	sprint(buf, "unknown error %x", id);
	return buf;
}

QLock apmlock;
int apmdebug;

static int
_apmcall(int fd, Ureg *u)
{
if(apmdebug) fprint(2, "call ax 0x%lux bx 0x%lux cx 0x%lux\n",
	u->ax&0xFFFF, u->bx&0xFFFF, u->cx&0xFFFF);

	seek(fd, 0, 0);
	if(write(fd, u, sizeof *u) != sizeof *u)
		return -1;

	seek(fd, 0, 0);
	if(read(fd, u, sizeof *u) != sizeof *u)
		return -1;

if(apmdebug) fprint(2, "flags 0x%lux ax 0x%lux bx 0x%lux cx 0x%lux\n",
	u->flags&0xFFFF, u->ax&0xFFFF, u->bx&0xFFFF, u->cx&0xFFFF);

	if(u->flags & 1) {	/* carry flag */
		werrstr("%s", apmerror(u->ax>>8));
		return -1;
	}
	return 0;
}

static int
apmcall(int fd, Ureg *u)
{
	int r;

	qlock(&apmlock);
	r = _apmcall(fd, u);
	qunlock(&apmlock);
	return r;
}

typedef struct Apm Apm;
typedef struct Battery Battery;

struct Battery {
	int status;
	int percent;
	int time;
};

enum {
	Mbattery = 4,
};
struct Apm {
	int fd;

	int verhi;
	int verlo;

	int acstatus;
	int nbattery;

	int capabilities;

	Battery battery[Mbattery];
};
enum {
	AcUnknown = 0,		/* Apm.acstatus */
	AcOffline,
	AcOnline,
	AcBackup,

	BatteryUnknown = 0,	/* Battery.status */
	BatteryHigh,
	BatteryLow,
	BatteryCritical,
	BatteryCharging,
};

static char*
acstatusstr[] = {
[AcUnknown]	"unknown",
[AcOffline]	"offline",
[AcOnline]	"online",
[AcBackup]	"backup",
};

static char*
batterystatusstr[] = {
[BatteryUnknown] "unknown",
[BatteryHigh]	"high",
[BatteryLow]	"low",
[BatteryCritical]	"critical",
[BatteryCharging]	"charging",
};

static char*
powerstatestr[] = {
[PowerOff]	"off",
[PowerSuspend]	"suspend",
[PowerStandby]	"standby",
[PowerEnabled]	"on",
};

static char*
xstatus(char **str, int nstr, int x)
{
	if(0 <= x && x < nstr && str[x])
		return str[x];
	return "unknown";
}

static char*
batterystatus(int b)
{
	return xstatus(batterystatusstr, nelem(batterystatusstr), b);
}

static char*
powerstate(int s)
{
	return xstatus(powerstatestr, nelem(powerstatestr), s);
}

static char*
acstatus(int a)
{
	return xstatus(acstatusstr, nelem(acstatusstr), a);
}
	  
static int
apmversion(Apm *apm)
{
	Ureg u;

	u.ax = CmdDriverVersion;
	u.bx = 0x0000;
	u.cx = 0x0102;
	if(apmcall(apm->fd, &u) < 0)
		return -1;

	apm->verhi = u.cx>>8;
	apm->verlo = u.cx & 0xFF;

	return u.cx;
}

static int
apmcpuidle(Apm *apm)
{
	Ureg u;

	u.ax = CmdCpuIdle;
	return apmcall(apm->fd, &u);
}

static int
apmcpubusy(Apm *apm)
{
	Ureg u;

	u.ax = CmdCpuBusy;
	return apmcall(apm->fd, &u);
}

static int
apmsetpowerstate(Apm *apm, int dev, int state)
{
	Ureg u;

	u.ax = CmdSetPowerState;
	u.bx = dev;
	u.cx = state;
	return apmcall(apm->fd, &u);
}

static int
apmsetpowermgmt(Apm *apm, int dev, int state)
{
	Ureg u;

	u.ax = CmdSetPowerMgmt;
	u.bx = dev;
	u.cx = state;
	return apmcall(apm->fd, &u);
}

static int
apmrestoredefaults(Apm *apm, int dev)
{
	Ureg u;

	u.ax = CmdRestoreDefaults;
	u.bx = dev;
	return apmcall(apm->fd, &u);
}

static int
apmgetpowerstatus(Apm *apm, int dev)
{
	Battery *b;
	Ureg u;

	if(dev == DevAll)
		b = &apm->battery[0];
	else if((dev & DevMask) == DevBattery) {
		if(dev - DevBattery < nelem(apm->battery))
			b = &apm->battery[dev - DevBattery];
		else
			b = nil;
	} else {
		werrstr("bad device number");
		return -1;
	}

	u.ax = CmdGetPowerStatus;
	u.bx = dev;

	if(apmcall(apm->fd, &u) < 0)
		return -1;

	if((dev & DevMask) == DevBattery)
		apm->nbattery = u.si;

	switch(u.bx>>8) {
	case 0x00:
		apm->acstatus = AcOffline;
		break;
	case 0x01:
		apm->acstatus = AcOnline;
		break;
	case 0x02:
		apm->acstatus = AcBackup;
		break;
	default:
		apm->acstatus = AcUnknown;
		break;
	}

	if(b != nil) {
		switch(u.bx&0xFF) {
		case 0x00:
			b->status = BatteryHigh;
			break;
		case 0x01:
			b->status = BatteryLow;
			break;
		case 0x02:
			b->status = BatteryCritical;
			break;
		case 0x03:
			b->status = BatteryCharging;
			break;
		default:
			b->status = BatteryUnknown;
			break;
		}

		if((u.cx & 0xFF) == 0xFF)
			b->percent = -1;
		else
			b->percent = u.cx & 0xFF;

		if((u.dx&0xFFFF) == 0xFFFF)
			b->time = -1;
		else if(u.dx & 0x8000)
			b->time = 60*(u.dx & 0x7FFF);
		else
			b->time = u.dx & 0x7FFF;
	}

	return 0;
}

static int
apmgetevent(Apm *apm)
{
	Ureg u;

	u.ax = CmdGetPMEvent;
	u.bx = 0;
	u.cx = 0;

	//when u.bx == NotifyNormalResume or NotifyCriticalResume,
	//u.cx & 1 indicates PCMCIA socket was on while suspended,
	//u.cx & 1 == 0 indicates was off.

	if(apmcall(apm->fd, &u) < 0)
		return -1;

	return u.bx;
}

static int
apmgetpowerstate(Apm *apm, int dev)
{
	Ureg u;

	u.ax = CmdGetPowerState;
	u.bx = dev;
	u.cx = 0;

	if(apmcall(apm->fd, &u) < 0)
		return -1;

	return u.cx;
}

static int
apmgetpowermgmt(Apm *apm, int dev)
{
	Ureg u;

	u.ax = CmdGetPowerMgmt;
	u.bx = dev;

	if(apmcall(apm->fd, &u) < 0)
		return -1;

	return u.cx;
}

static int
apmgetcapabilities(Apm *apm)
{
	Ureg u;

	u.ax = CmdGetCapabilities;
	u.bx = DevBios;

	if(apmcall(apm->fd, &u) < 0)
		return -1;

	apm->nbattery = u.bx & 0xFF;
	apm->capabilities &= ~0xFFFF;
	apm->capabilities |= u.cx;
	return 0;
}

static int
apminstallationcheck(Apm *apm)
{
	Ureg u;

	u.ax = CmdInstallationCheck;
	u.bx = DevBios;
	if(apmcall(apm->fd, &u) < 0)
		return -1;

	if(u.cx & 0x0004)
		apm->capabilities |= CapSlowCpu;
	else
		apm->capabilities &= ~CapSlowCpu;
	return 0;
}

void
apmsetdisplaystate(Apm *apm, int s)
{
	apmsetpowerstate(apm, DevDisplay, s);
}

void
apmblank(Apm *apm)
{
	apmsetdisplaystate(apm, PowerStandby);
}

void
apmunblank(Apm *apm)
{
	apmsetdisplaystate(apm, PowerEnabled);
}

void
apmsuspend(Apm *apm)
{
	apmsetpowerstate(apm, DevAll, PowerSuspend);
}

Apm apm;

void
powerprint(void)
{
	print("%s", ctime(time(0)));
	if(apmgetpowerstatus(&apm, DevAll) == 0) {
		print("%d batteries\n", apm.nbattery);
		print("battery 0: status %s percent %d time %d:%.2d\n",
			batterystatus(apm.battery[0].status), apm.battery[0].percent,
			apm.battery[0].time/60, apm.battery[0].time%60);
	}
}

void*
erealloc(void *v, ulong n)
{
	v = realloc(v, n);
	if(v == nil)
		sysfatal("out of memory reallocating %lud", n);
	setmalloctag(v, getcallerpc(&v));
	return v;
}

void*
emalloc(ulong n)
{
	void *v;

	v = malloc(n);
	if(v == nil)
		sysfatal("out of memory allocating %lud", n);
	memset(v, 0, n);
	setmalloctag(v, getcallerpc(&n));
	return v;
}

char*
estrdup(char *s)
{
	int l;
	char *t;

	if (s == nil)
		return nil;
	l = strlen(s)+1;
	t = emalloc(l);
	memcpy(t, s, l);
	setmalloctag(t, getcallerpc(&s));
	return t;
}

char*