/*-
 * Copyright 2004 Colin Percival.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted providing that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Colin Percival.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR``AS IS'' AND ANY EXPRESS OR 
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/sysctl.h>

#if __FreeBSD_version < 500101
#include <sys/dkstat.h>
#else
#include <sys/resource.h>
#endif

#include <machine/apm_bios.h>

#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define MODE_MIN	0
#define MODE_ADAPTIVE	1
#define MODE_MAX	2
#define SRC_AC		0
#define SRC_BATTERY	1
#define SRC_UNKNOWN	2
#define ACPIAC		"hw.acpi.acline"
#define APMDEV		"/dev/apm"

static int readtimes(long * idle, long * total);
static int readfreqs(int * numfreqs, int ** freqs);
static int setcurfreq(int freq);
static void readmode(char * arg, int * mode, int ch);
static void usage(void);

const char *modes[] = {
	"AC",
	"battery",
	"unknown"
};

static int readtimes(long * idle, long * total)
{
	static long idle_old, total_old;
	long cp_time[CPUSTATES];
	size_t cp_time_len = sizeof(cp_time);
	long total_new, i;
	int error;

	if ((error = sysctlbyname("kern.cp_time", (void *)cp_time,
	    &cp_time_len, NULL, 0)) != 0)
		return error;
	for (total_new = 0, i = 0; i < CPUSTATES; i++)
		total_new += cp_time[i];

	if (idle)
		*idle = cp_time[CP_IDLE] - idle_old;
	if (total)
		*total = total_new - total_old;

	idle_old = cp_time[CP_IDLE];
	total_old = total_new;

	return 0;
}

static int readfreqs(int * numfreqs, int ** freqs)
{
	char *freqstr, *p, *q;
	int i;
	size_t len = 0;

	if (sysctlbyname("hw.est_freqs", NULL, &len, NULL, 0))
		return -1;
	if ((freqstr = malloc(len)) == NULL)
		return -1;
	if (sysctlbyname("hw.est_freqs", (void *)freqstr, &len, NULL, 0))
		return -1;

	*numfreqs = 1;
	for (p = freqstr; *p != '\0'; p++)
		if (*p == ' ')
			(*numfreqs)++;

	if ((*freqs = malloc(*numfreqs * sizeof(int))) == NULL) {
		free(freqstr);
		return -1;
	}
	for (i = 0, p = freqstr; i < *numfreqs; i++) {
		q = strchr(p, ' ');
		if (q != NULL)
			*q = '\0';
		if (sscanf(p, "%d", &(*freqs)[i]) != 1) {
			free(freqstr);
			free(*freqs);
			return -1;
		}
		p = q + 1;
	}

	free(freqstr);
	return 0;
}

static int setcurfreq(int freq)
{

	if (sysctlbyname("hw.est_curfreq", NULL, NULL, &freq, sizeof(freq)))
		return -1;

	return 0;
}

static void readmode(char * arg, int * mode, int ch)
{

	if (strcmp(arg, "min") == 0)
		*mode = MODE_MIN;
	else if (strcmp(arg, "max") == 0)
		*mode = MODE_MAX;
	else if (strcmp(arg, "adaptive") == 0)
		*mode = MODE_ADAPTIVE;
	else
		errx(1, "Bad option: -%c %s", (char)ch, optarg);
}

static void usage(void)
{

	(void)fprintf(stderr, "usage: estctrl [-v] [-a mode] [-b mode] "
	    "[-d mode]\n");
	exit(1);
}

int main(int argc, char * argv[])
{
	struct apm_info info;
	long idle, total;
	int * freqs, numfreqs;
	int curfreq, i;
	int ch, mode_ac, mode_battery, mode_default, acline, mode;
	int apm_fd;
	int vflag;
	size_t len;

	/* Default mode is adaptive */
	mode_ac = mode_battery = mode_default = MODE_ADAPTIVE;
	vflag = 0;

	while ((ch = getopt(argc, argv, "a:b:d:v")) != -1)
		switch((char)ch) {
		case 'a':
			readmode(optarg, &mode_ac, ch);
			break;
		case 'b':
			readmode(optarg, &mode_battery, ch);
			break;
		case 'd':
			readmode(optarg, &mode_default, ch);
			break;
		case 'v':
			vflag = 1;
			break;
		default:
			usage();
		}

	if (readtimes(NULL, NULL))
		err(1, "readtimes");
	if (readfreqs(&numfreqs, &freqs))
		err(1, "Error reading supported CPU frequencies");

	len = sizeof(acline);
	if (sysctlbyname(ACPIAC, &acline, &len, NULL, 0)) {
		/* ACPI disabled, try APM */
		apm_fd = open(APMDEV, O_RDONLY);
		if (apm_fd == -1)
			warnx("Cannot read AC line status, "
			    "using default settings");
	} else
		apm_fd = -1;

	do {
		usleep(500000);	/* Check status every 0.5 seconds */

		if (apm_fd != -1) {
			if (ioctl(apm_fd, APMIO_GETINFO, &info) == -1)
				acline = SRC_UNKNOWN;
			else
				acline = info.ai_acline ? SRC_AC : SRC_BATTERY;
		} else {
			len = sizeof(acline);
			if (sysctlbyname(ACPIAC, &acline, &len, NULL, 0))
				acline = SRC_UNKNOWN;
			else
				acline = acline ? SRC_AC : SRC_BATTERY;
		}

		switch(acline) {
		case SRC_AC:
			mode = mode_ac;
			break;
		case SRC_BATTERY:
			mode = mode_battery;
			break;
		case SRC_UNKNOWN:
			mode = mode_default;
			break;
		default:
			errx(1, "Programming error");
		}

		len = sizeof(curfreq);
		if (sysctlbyname("hw.est_curfreq", &curfreq, &len, NULL, 0))
			err(1, "Error reading current CPU frequency");

		if (mode == MODE_MIN) {
			if (curfreq != freqs[0]) {
				if (vflag)
					printf("Now operating on %s power; "
					    "changing frequency to %dMHz\n",
					    modes[acline], freqs[0]);
				if (setcurfreq(freqs[0]))
					err(1, "Error setting CPU frequency");
			}
			continue;
		}

		if (mode == MODE_MAX) {
			if (curfreq != freqs[numfreqs - 1]) {
				if (vflag)
					printf("Now operating on %s power; "
					    "changing frequency to %dMHz\n",
					    modes[acline], freqs[numfreqs - 1]);
				if (setcurfreq(freqs[numfreqs - 1]))
					err(1, "Error setting CPU frequency");
			}
			continue;
		}

		if (readtimes(&idle, &total))
			err(1, "readtimes");

		if ((idle < total / 2) && (curfreq < freqs[numfreqs - 1])) {
			for (i = 0; i < numfreqs; i++)
				if (curfreq < freqs[i])
					break;
			if (vflag)
				printf("Idle time < 50%%, increasing clock"
				    " speed from %dMHz to %dMHz\n", curfreq,
				    freqs[i]);
			if (setcurfreq(freqs[i]))
				err(1, "Error setting CPU frequency");
		}
		if ((idle > (total * 3) / 4) && (curfreq > freqs[0])) {
			for (i = numfreqs - 1; i >= 0; i--)
				if (curfreq > freqs[i])
					break;
			if (vflag)
				printf("Idle time > 75%%, decreasing clock"
				    " speed from %dMHz to %dMHz\n", curfreq,
				    freqs[i]);
			if (setcurfreq(freqs[i]))
				err(1, "Error setting CPU frequency");
		}
	} while(1);

	/* NOTREACHED */
	if (apm_fd != -1)
		close(apm_fd);

	return 0;
}