Merge branch 'viro'

1 files changed, 698 insertions, 0 deletions

diff --git a/drivers/macintosh/windfarm_pm112.c b/drivers/macintosh/windfarm_pm112.c
new file mode 100644
index 000000000000..c2a4e689c784
--- /dev/null
+++ b/drivers/macintosh/windfarm_pm112.c
@@ -0,0 +1,698 @@
+/*
+ * Windfarm PowerMac thermal control.
+ * Control loops for machines with SMU and PPC970MP processors.
+ *
+ * Copyright (C) 2005 Paul Mackerras, IBM Corp. <paulus@samba.org>
+ * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
+ *
+ * Use and redistribute under the terms of the GNU GPL v2.
+ */
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <asm/prom.h>
+#include <asm/smu.h>
+
+#include "windfarm.h"
+#include "windfarm_pid.h"
+
+#define VERSION "0.2"
+
+#define DEBUG
+#undef LOTSA_DEBUG
+
+#ifdef DEBUG
+#define DBG(args...)	printk(args)
+#else
+#define DBG(args...)	do { } while(0)
+#endif
+
+#ifdef LOTSA_DEBUG
+#define DBG_LOTS(args...)	printk(args)
+#else
+#define DBG_LOTS(args...)	do { } while(0)
+#endif
+
+/* define this to force CPU overtemp to 60 degree, useful for testing
+ * the overtemp code
+ */
+#undef HACKED_OVERTEMP
+
+/* We currently only handle 2 chips, 4 cores... */
+#define NR_CHIPS	2
+#define NR_CORES	4
+#define NR_CPU_FANS	3 * NR_CHIPS
+
+/* Controls and sensors */
+static struct wf_sensor *sens_cpu_temp[NR_CORES];
+static struct wf_sensor *sens_cpu_power[NR_CORES];
+static struct wf_sensor *hd_temp;
+static struct wf_sensor *slots_power;
+static struct wf_sensor *u4_temp;
+
+static struct wf_control *cpu_fans[NR_CPU_FANS];
+static char *cpu_fan_names[NR_CPU_FANS] = {
+	"cpu-rear-fan-0",
+	"cpu-rear-fan-1",
+	"cpu-front-fan-0",
+	"cpu-front-fan-1",
+	"cpu-pump-0",
+	"cpu-pump-1",
+};
+static struct wf_control *cpufreq_clamp;
+
+/* Second pump isn't required (and isn't actually present) */
+#define CPU_FANS_REQD		(NR_CPU_FANS - 2)
+#define FIRST_PUMP		4
+#define LAST_PUMP		5
+
+/* We keep a temperature history for average calculation of 180s */
+#define CPU_TEMP_HIST_SIZE	180
+
+/* Scale factor for fan speed, *100 */
+static int cpu_fan_scale[NR_CPU_FANS] = {
+	100,
+	100,
+	97,		/* inlet fans run at 97% of exhaust fan */
+	97,
+	100,		/* updated later */
+	100,		/* updated later */
+};
+
+static struct wf_control *backside_fan;
+static struct wf_control *slots_fan;
+static struct wf_control *drive_bay_fan;
+
+/* PID loop state */
+static struct wf_cpu_pid_state cpu_pid[NR_CORES];
+static u32 cpu_thist[CPU_TEMP_HIST_SIZE];
+static int cpu_thist_pt;
+static s64 cpu_thist_total;
+static s32 cpu_all_tmax = 100 << 16;
+static int cpu_last_target;
+static struct wf_pid_state backside_pid;
+static int backside_tick;
+static struct wf_pid_state slots_pid;
+static int slots_started;
+static struct wf_pid_state drive_bay_pid;
+static int drive_bay_tick;
+
+static int nr_cores;
+static int have_all_controls;
+static int have_all_sensors;
+static int started;
+
+static int failure_state;
+#define FAILURE_SENSOR		1
+#define FAILURE_FAN		2
+#define FAILURE_PERM		4
+#define FAILURE_LOW_OVERTEMP	8
+#define FAILURE_HIGH_OVERTEMP	16
+
+/* Overtemp values */
+#define LOW_OVER_AVERAGE	0
+#define LOW_OVER_IMMEDIATE	(10 << 16)
+#define LOW_OVER_CLEAR		((-10) << 16)
+#define HIGH_OVER_IMMEDIATE	(14 << 16)
+#define HIGH_OVER_AVERAGE	(10 << 16)
+#define HIGH_OVER_IMMEDIATE	(14 << 16)
+
+
+/* Implementation... */
+static int create_cpu_loop(int cpu)
+{
+	int chip = cpu / 2;
+	int core = cpu & 1;
+	struct smu_sdbp_header *hdr;
+	struct smu_sdbp_cpupiddata *piddata;
+	struct wf_cpu_pid_param pid;
+	struct wf_control *main_fan = cpu_fans[0];
+	s32 tmax;
+	int fmin;
+
+	/* Get PID params from the appropriate SAT */
+	hdr = smu_sat_get_sdb_partition(chip, 0xC8 + core, NULL);
+	if (hdr == NULL) {
+		printk(KERN_WARNING"windfarm: can't get CPU PID fan config\n");
+		return -EINVAL;
+	}
+	piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];
+
+	/* Get FVT params to get Tmax; if not found, assume default */
+	hdr = smu_sat_get_sdb_partition(chip, 0xC4 + core, NULL);
+	if (hdr) {
+		struct smu_sdbp_fvt *fvt = (struct smu_sdbp_fvt *)&hdr[1];
+		tmax = fvt->maxtemp << 16;
+	} else
+		tmax = 95 << 16;	/* default to 95 degrees C */
+
+	/* We keep a global tmax for overtemp calculations */
+	if (tmax < cpu_all_tmax)
+		cpu_all_tmax = tmax;
+
+	/*
+	 * Darwin has a minimum fan speed of 1000 rpm for the 4-way and
+	 * 515 for the 2-way.  That appears to be overkill, so for now,
+	 * impose a minimum of 750 or 515.
+	 */
+	fmin = (nr_cores > 2) ? 750 : 515;
+
+	/* Initialize PID loop */
+	pid.interval = 1;	/* seconds */
+	pid.history_len = piddata->history_len;
+	pid.gd = piddata->gd;
+	pid.gp = piddata->gp;
+	pid.gr = piddata->gr / piddata->history_len;
+	pid.pmaxadj = (piddata->max_power << 16) - (piddata->power_adj << 8);
+	pid.ttarget = tmax - (piddata->target_temp_delta << 16);
+	pid.tmax = tmax;
+	pid.min = main_fan->ops->get_min(main_fan);
+	pid.max = main_fan->ops->get_max(main_fan);
+	if (pid.min < fmin)
+		pid.min = fmin;
+
+	wf_cpu_pid_init(&cpu_pid[cpu], &pid);
+	return 0;
+}
+
+static void cpu_max_all_fans(void)
+{
+	int i;
+
+	/* We max all CPU fans in case of a sensor error. We also do the
+	 * cpufreq clamping now, even if it's supposedly done later by the
+	 * generic code anyway, we do it earlier here to react faster
+	 */
+	if (cpufreq_clamp)
+		wf_control_set_max(cpufreq_clamp);
+	for (i = 0; i < NR_CPU_FANS; ++i)
+		if (cpu_fans[i])
+			wf_control_set_max(cpu_fans[i]);
+}
+
+static int cpu_check_overtemp(s32 temp)
+{
+	int new_state = 0;
+	s32 t_avg, t_old;
+
+	/* First check for immediate overtemps */
+	if (temp >= (cpu_all_tmax + LOW_OVER_IMMEDIATE)) {
+		new_state |= FAILURE_LOW_OVERTEMP;
+		if ((failure_state & FAILURE_LOW_OVERTEMP) == 0)
+			printk(KERN_ERR "windfarm: Overtemp due to immediate CPU"
+			       " temperature !\n");
+	}
+	if (temp >= (cpu_all_tmax + HIGH_OVER_IMMEDIATE)) {
+		new_state |= FAILURE_HIGH_OVERTEMP;
+		if ((failure_state & FAILURE_HIGH_OVERTEMP) == 0)
+			printk(KERN_ERR "windfarm: Critical overtemp due to"
+			       " immediate CPU temperature !\n");
+	}
+
+	/* We calculate a history of max temperatures and use that for the
+	 * overtemp management
+	 */
+	t_old = cpu_thist[cpu_thist_pt];
+	cpu_thist[cpu_thist_pt] = temp;
+	cpu_thist_pt = (cpu_thist_pt + 1) % CPU_TEMP_HIST_SIZE;
+	cpu_thist_total -= t_old;
+	cpu_thist_total += temp;
+	t_avg = cpu_thist_total / CPU_TEMP_HIST_SIZE;
+
+	DBG_LOTS("t_avg = %d.%03d (out: %d.%03d, in: %d.%03d)\n",
+		 FIX32TOPRINT(t_avg), FIX32TOPRINT(t_old), FIX32TOPRINT(temp));
+
+	/* Now check for average overtemps */
+	if (t_avg >= (cpu_all_tmax + LOW_OVER_AVERAGE)) {
+		new_state |= FAILURE_LOW_OVERTEMP;
+		if ((failure_state & FAILURE_LOW_OVERTEMP) == 0)
+			printk(KERN_ERR "windfarm: Overtemp due to average CPU"
+			       " temperature !\n");
+	}
+	if (t_avg >= (cpu_all_tmax + HIGH_OVER_AVERAGE)) {
+		new_state |= FAILURE_HIGH_OVERTEMP;
+		if ((failure_state & FAILURE_HIGH_OVERTEMP) == 0)
+			printk(KERN_ERR "windfarm: Critical overtemp due to"
+			       " average CPU temperature !\n");
+	}
+
+	/* Now handle overtemp conditions. We don't currently use the windfarm
+	 * overtemp handling core as it's not fully suited to the needs of those
+	 * new machine. This will be fixed later.
+	 */
+	if (new_state) {
+		/* High overtemp -> immediate shutdown */
+		if (new_state & FAILURE_HIGH_OVERTEMP)
+			machine_power_off();
+		if ((failure_state & new_state) != new_state)
+			cpu_max_all_fans();
+		failure_state |= new_state;
+	} else if ((failure_state & FAILURE_LOW_OVERTEMP) &&
+		   (temp < (cpu_all_tmax + LOW_OVER_CLEAR))) {
+		printk(KERN_ERR "windfarm: Overtemp condition cleared !\n");
+		failure_state &= ~FAILURE_LOW_OVERTEMP;
+	}
+
+	return failure_state & (FAILURE_LOW_OVERTEMP | FAILURE_HIGH_OVERTEMP);
+}
+
+static void cpu_fans_tick(void)
+{
+	int err, cpu;
+	s32 greatest_delta = 0;
+	s32 temp, power, t_max = 0;
+	int i, t, target = 0;
+	struct wf_sensor *sr;
+	struct wf_control *ct;
+	struct wf_cpu_pid_state *sp;
+
+	DBG_LOTS(KERN_DEBUG);
+	for (cpu = 0; cpu < nr_cores; ++cpu) {
+		/* Get CPU core temperature */
+		sr = sens_cpu_temp[cpu];
+		err = sr->ops->get_value(sr, &temp);
+		if (err) {
+			DBG("\n");
+			printk(KERN_WARNING "windfarm: CPU %d temperature "
+			       "sensor error %d\n", cpu, err);
+			failure_state |= FAILURE_SENSOR;
+			cpu_max_all_fans();
+			return;
+		}
+
+		/* Keep track of highest temp */
+		t_max = max(t_max, temp);
+
+		/* Get CPU power */
+		sr = sens_cpu_power[cpu];
+		err = sr->ops->get_value(sr, &power);
+		if (err) {
+			DBG("\n");
+			printk(KERN_WARNING "windfarm: CPU %d power "
+			       "sensor error %d\n", cpu, err);
+			failure_state |= FAILURE_SENSOR;
+			cpu_max_all_fans();
+			return;
+		}
+
+		/* Run PID */
+		sp = &cpu_pid[cpu];
+		t = wf_cpu_pid_run(sp, power, temp);
+
+		if (cpu == 0 || sp->last_delta > greatest_delta) {
+			greatest_delta = sp->last_delta;
+			target = t;
+		}
+		DBG_LOTS("[%d] P=%d.%.3d T=%d.%.3d ",
+		    cpu, FIX32TOPRINT(power), FIX32TOPRINT(temp));
+	}
+	DBG_LOTS("fans = %d, t_max = %d.%03d\n", target, FIX32TOPRINT(t_max));
+
+	/* Darwin limits decrease to 20 per iteration */
+	if (target < (cpu_last_target - 20))
+		target = cpu_last_target - 20;
+	cpu_last_target = target;
+	for (cpu = 0; cpu < nr_cores; ++cpu)
+		cpu_pid[cpu].target = target;
+
+	/* Handle possible overtemps */
+	if (cpu_check_overtemp(t_max))
+		return;
+
+	/* Set fans */
+	for (i = 0; i < NR_CPU_FANS; ++i) {
+		ct = cpu_fans[i];
+		if (ct == NULL)
+			continue;
+		err = ct->ops->set_value(ct, target * cpu_fan_scale[i] / 100);
+		if (err) {
+			printk(KERN_WARNING "windfarm: fan %s reports "
+			       "error %d\n", ct->name, err);
+			failure_state |= FAILURE_FAN;
+			break;
+		}
+	}
+}
+
+/* Backside/U4 fan */
+static struct wf_pid_param backside_param = {
+	.interval	= 5,
+	.history_len	= 2,
+	.gd		= 48 << 20,
+	.gp		= 5 << 20,
+	.gr		= 0,
+	.itarget	= 64 << 16,
+	.additive	= 1,
+};
+
+static void backside_fan_tick(void)
+{
+	s32 temp;
+	int speed;
+	int err;
+
+	if (!backside_fan || !u4_temp)
+		return;
+	if (!backside_tick) {
+		/* first time; initialize things */
+		backside_param.min = backside_fan->ops->get_min(backside_fan);
+		backside_param.max = backside_fan->ops->get_max(backside_fan);
+		wf_pid_init(&backside_pid, &backside_param);
+		backside_tick = 1;
+	}
+	if (--backside_tick > 0)
+		return;
+	backside_tick = backside_pid.param.interval;
+
+	err = u4_temp->ops->get_value(u4_temp, &temp);
+	if (err) {
+		printk(KERN_WARNING "windfarm: U4 temp sensor error %d\n",
+		       err);
+		failure_state |= FAILURE_SENSOR;
+		wf_control_set_max(backside_fan);
+		return;
+	}
+	speed = wf_pid_run(&backside_pid, temp);
+	DBG_LOTS("backside PID temp=%d.%.3d speed=%d\n",
+		 FIX32TOPRINT(temp), speed);
+
+	err = backside_fan->ops->set_value(backside_fan, speed);
+	if (err) {
+		printk(KERN_WARNING "windfarm: backside fan error %d\n", err);
+		failure_state |= FAILURE_FAN;
+	}
+}
+
+/* Drive bay fan */
+static struct wf_pid_param drive_bay_prm = {
+	.interval	= 5,
+	.history_len	= 2,
+	.gd		= 30 << 20,
+	.gp		= 5 << 20,
+	.gr		= 0,
+	.itarget	= 40 << 16,
+	.additive	= 1,
+};
+
+static void drive_bay_fan_tick(void)
+{
+	s32 temp;
+	int speed;
+	int err;
+
+	if (!drive_bay_fan || !hd_temp)
+		return;
+	if (!drive_bay_tick) {
+		/* first time; initialize things */
+		drive_bay_prm.min = drive_bay_fan->ops->get_min(drive_bay_fan);
+		drive_bay_prm.max = drive_bay_fan->ops->get_max(drive_bay_fan);
+		wf_pid_init(&drive_bay_pid, &drive_bay_prm);
+		drive_bay_tick = 1;
+	}
+	if (--drive_bay_tick > 0)
+		return;
+	drive_bay_tick = drive_bay_pid.param.interval;
+
+	err = hd_temp->ops->get_value(hd_temp, &temp);
+	if (err) {
+		printk(KERN_WARNING "windfarm: drive bay temp sensor "
+		       "error %d\n", err);
+		failure_state |= FAILURE_SENSOR;
+		wf_control_set_max(drive_bay_fan);
+		return;
+	}
+	speed = wf_pid_run(&drive_bay_pid, temp);
+	DBG_LOTS("drive_bay PID temp=%d.%.3d speed=%d\n",
+		 FIX32TOPRINT(temp), speed);
+
+	err = drive_bay_fan->ops->set_value(drive_bay_fan, speed);
+	if (err) {
+		printk(KERN_WARNING "windfarm: drive bay fan error %d\n", err);
+		failure_state |= FAILURE_FAN;
+	}
+}
+
+/* PCI slots area fan */
+/* This makes the fan speed proportional to the power consumed */
+static struct wf_pid_param slots_param = {
+	.interval	= 1,
+	.history_len	= 2,
+	.gd		= 0,
+	.gp		= 0,
+	.gr		= 0x1277952,
+	.itarget	= 0,
+	.min		= 1560,
+	.max		= 3510,
+};
+
+static void slots_fan_tick(void)
+{
+	s32 power;
+	int speed;
+	int err;
+
+	if (!slots_fan || !slots_power)
+		return;
+	if (!slots_started) {
+		/* first time; initialize things */
+		wf_pid_init(&slots_pid, &slots_param);
+		slots_started = 1;
+	}
+
+	err = slots_power->ops->get_value(slots_power, &power);
+	if (err) {
+		printk(KERN_WARNING "windfarm: slots power sensor error %d\n",
+		       err);
+		failure_state |= FAILURE_SENSOR;
+		wf_control_set_max(slots_fan);
+		return;
+	}
+	speed = wf_pid_run(&slots_pid, power);
+	DBG_LOTS("slots PID power=%d.%.3d speed=%d\n",
+		 FIX32TOPRINT(power), speed);
+
+	err = slots_fan->ops->set_value(slots_fan, speed);
+	if (err) {
+		printk(KERN_WARNING "windfarm: slots fan error %d\n", err);
+		failure_state |= FAILURE_FAN;
+	}
+}
+
+static void set_fail_state(void)
+{
+	int i;
+
+	if (cpufreq_clamp)
+		wf_control_set_max(cpufreq_clamp);
+	for (i = 0; i < NR_CPU_FANS; ++i)
+		if (cpu_fans[i])
+			wf_control_set_max(cpu_fans[i]);
+	if (backside_fan)
+		wf_control_set_max(backside_fan);
+	if (slots_fan)
+		wf_control_set_max(slots_fan);
+	if (drive_bay_fan)
+		wf_control_set_max(drive_bay_fan);
+}
+
+static void pm112_tick(void)
+{
+	int i, last_failure;
+
+	if (!started) {
+		started = 1;
+		for (i = 0; i < nr_cores; ++i) {
+			if (create_cpu_loop(i) < 0) {
+				failure_state = FAILURE_PERM;
+				set_fail_state();
+				break;
+			}
+		}
+		DBG_LOTS("cpu_all_tmax=%d.%03d\n", FIX32TOPRINT(cpu_all_tmax));
+
+#ifdef HACKED_OVERTEMP
+		cpu_all_tmax = 60 << 16;
+#endif
+	}
+
+	/* Permanent failure, bail out */
+	if (failure_state & FAILURE_PERM)
+		return;
+	/* Clear all failure bits except low overtemp which will be eventually
+	 * cleared by the control loop itself
+	 */
+	last_failure = failure_state;
+	failure_state &= FAILURE_LOW_OVERTEMP;
+	cpu_fans_tick();
+	backside_fan_tick();
+	slots_fan_tick();
+	drive_bay_fan_tick();
+
+	DBG_LOTS("last_failure: 0x%x, failure_state: %x\n",
+		 last_failure, failure_state);
+
+	/* Check for failures. Any failure causes cpufreq clamping */
+	if (failure_state && last_failure == 0 && cpufreq_clamp)
+		wf_control_set_max(cpufreq_clamp);
+	if (failure_state == 0 && last_failure && cpufreq_clamp)
+		wf_control_set_min(cpufreq_clamp);
+
+	/* That's it for now, we might want to deal with other failures
+	 * differently in the future though
+	 */
+}
+
+static void pm112_new_control(struct wf_control *ct)
+{
+	int i, max_exhaust;
+
+	if (cpufreq_clamp == NULL && !strcmp(ct->name, "cpufreq-clamp")) {
+		if (wf_get_control(ct) == 0)
+			cpufreq_clamp = ct;
+	}
+
+	for (i = 0; i < NR_CPU_FANS; ++i) {
+		if (!strcmp(ct->name, cpu_fan_names[i])) {
+			if (cpu_fans[i] == NULL && wf_get_control(ct) == 0)
+				cpu_fans[i] = ct;
+			break;
+		}
+	}
+	if (i >= NR_CPU_FANS) {
+		/* not a CPU fan, try the others */
+		if (!strcmp(ct->name, "backside-fan")) {
+			if (backside_fan == NULL && wf_get_control(ct) == 0)
+				backside_fan = ct;
+		} else if (!strcmp(ct->name, "slots-fan")) {
+			if (slots_fan == NULL && wf_get_control(ct) == 0)
+				slots_fan = ct;
+		} else if (!strcmp(ct->name, "drive-bay-fan")) {
+			if (drive_bay_fan == NULL && wf_get_control(ct) == 0)
+				drive_bay_fan = ct;
+		}
+		return;
+	}
+
+	for (i = 0; i < CPU_FANS_REQD; ++i)
+		if (cpu_fans[i] == NULL)
+			return;
+
+	/* work out pump scaling factors */
+	max_exhaust = cpu_fans[0]->ops->get_max(cpu_fans[0]);
+	for (i = FIRST_PUMP; i <= LAST_PUMP; ++i)
+		if ((ct = cpu_fans[i]) != NULL)
+			cpu_fan_scale[i] =
+				ct->ops->get_max(ct) * 100 / max_exhaust;
+
+	have_all_controls = 1;
+}
+
+static void pm112_new_sensor(struct wf_sensor *sr)
+{
+	unsigned int i;
+
+	if (have_all_sensors)
+		return;
+	if (!strncmp(sr->name, "cpu-temp-", 9)) {
+		i = sr->name[9] - '0';
+		if (sr->name[10] == 0 && i < NR_CORES &&
+		    sens_cpu_temp[i] == NULL && wf_get_sensor(sr) == 0)
+			sens_cpu_temp[i] = sr;
+
+	} else if (!strncmp(sr->name, "cpu-power-", 10)) {
+		i = sr->name[10] - '0';
+		if (sr->name[11] == 0 && i < NR_CORES &&
+		    sens_cpu_power[i] == NULL && wf_get_sensor(sr) == 0)
+			sens_cpu_power[i] = sr;
+	} else if (!strcmp(sr->name, "hd-temp")) {
+		if (hd_temp == NULL && wf_get_sensor(sr) == 0)
+			hd_temp = sr;
+	} else if (!strcmp(sr->name, "slots-power")) {
+		if (slots_power == NULL && wf_get_sensor(sr) == 0)
+			slots_power = sr;
+	} else if (!strcmp(sr->name, "u4-temp")) {
+		if (u4_temp == NULL && wf_get_sensor(sr) == 0)
+			u4_temp = sr;
+	} else
+		return;
+
+	/* check if we have all the sensors we need */
+	for (i = 0; i < nr_cores; ++i)
+		if (sens_cpu_temp[i] == NULL || sens_cpu_power[i] == NULL)
+			return;
+
+	have_all_sensors = 1;
+}
+
+static int pm112_wf_notify(struct notifier_block *self,
+			   unsigned long event, void *data)
+{
+	switch (event) {
+	case WF_EVENT_NEW_SENSOR:
+		pm112_new_sensor(data);
+		break;
+	case WF_EVENT_NEW_CONTROL:
+		pm112_new_control(data);
+		break;
+	case WF_EVENT_TICK:
+		if (have_all_controls && have_all_sensors)
+			pm112_tick();
+	}
+	return 0;
+}
+
+static struct notifier_block pm112_events = {
+	.notifier_call = pm112_wf_notify,
+};
+
+static int wf_pm112_probe(struct device *dev)
+{
+	wf_register_client(&pm112_events);
+	return 0;
+}
+
+static int wf_pm112_remove(struct device *dev)
+{
+	wf_unregister_client(&pm112_events);
+	/* should release all sensors and controls */
+	return 0;
+}
+
+static struct device_driver wf_pm112_driver = {
+	.name = "windfarm",
+	.bus = &platform_bus_type,
+	.probe = wf_pm112_probe,
+	.remove = wf_pm112_remove,
+};
+
+static int __init wf_pm112_init(void)
+{
+	struct device_node *cpu;
+
+	if (!machine_is_compatible("PowerMac11,2"))
+		return -ENODEV;
+
+	/* Count the number of CPU cores */
+	nr_cores = 0;
+	for (cpu = NULL; (cpu = of_find_node_by_type(cpu, "cpu")) != NULL; )
+		++nr_cores;
+
+	printk(KERN_INFO "windfarm: initializing for dual-core desktop G5\n");
+	driver_register(&wf_pm112_driver);
+	return 0;
+}
+
+static void __exit wf_pm112_exit(void)
+{
+	driver_unregister(&wf_pm112_driver);
+}
+
+module_init(wf_pm112_init);
+module_exit(wf_pm112_exit);
+
+MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
+MODULE_DESCRIPTION("Thermal control for PowerMac11,2");
+MODULE_LICENSE("GPL");