[PATCH] ppc64: Thermal control for SMU based machines

This adds a new thermal control framework for PowerMac, along with the
implementation for PowerMac8,1, PowerMac8,2 (iMac G5 rev 1 and 2), and
PowerMac9,1 (latest single CPU desktop). In the future, I expect to move
the older G5 thermal control to the new framework as well.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 879 insertions, 0 deletions

diff --git a/drivers/macintosh/windfarm_pm81.c b/drivers/macintosh/windfarm_pm81.c
new file mode 100644
index 000000000000..322c74b2687f
--- /dev/null
+++ b/drivers/macintosh/windfarm_pm81.c
@@ -0,0 +1,879 @@
+/*
+ * Windfarm PowerMac thermal control. iMac G5
+ *
+ * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ * Released under the term of the GNU GPL v2.
+ *
+ * The algorithm used is the PID control algorithm, used the same
+ * way the published Darwin code does, using the same values that
+ * are present in the Darwin 8.2 snapshot property lists (note however
+ * that none of the code has been re-used, it's a complete re-implementation
+ *
+ * The various control loops found in Darwin config file are:
+ *
+ * PowerMac8,1 and PowerMac8,2
+ * ===========================
+ *
+ * System Fans control loop. Different based on models. In addition to the
+ * usual PID algorithm, the control loop gets 2 additional pairs of linear
+ * scaling factors (scale/offsets) expressed as 4.12 fixed point values
+ * signed offset, unsigned scale)
+ *
+ * The targets are modified such as:
+ *  - the linked control (second control) gets the target value as-is
+ *    (typically the drive fan)
+ *  - the main control (first control) gets the target value scaled with
+ *    the first pair of factors, and is then modified as below
+ *  - the value of the target of the CPU Fan control loop is retreived,
+ *    scaled with the second pair of factors, and the max of that and
+ *    the scaled target is applied to the main control.
+ *
+ * # model_id: 2
+ *   controls       : system-fan, drive-bay-fan
+ *   sensors        : hd-temp
+ *   PID params     : G_d = 0x15400000
+ *                    G_p = 0x00200000
+ *                    G_r = 0x000002fd
+ *                    History = 2 entries
+ *                    Input target = 0x3a0000
+ *                    Interval = 5s
+ *   linear-factors : offset = 0xff38 scale  = 0x0ccd
+ *                    offset = 0x0208 scale  = 0x07ae
+ *
+ * # model_id: 3
+ *   controls       : system-fan, drive-bay-fan
+ *   sensors        : hd-temp
+ *   PID params     : G_d = 0x08e00000
+ *                    G_p = 0x00566666
+ *                    G_r = 0x0000072b
+ *                    History = 2 entries
+ *                    Input target = 0x350000
+ *                    Interval = 5s
+ *   linear-factors : offset = 0xff38 scale  = 0x0ccd
+ *                    offset = 0x0000 scale  = 0x0000
+ *
+ * # model_id: 5
+ *   controls       : system-fan
+ *   sensors        : hd-temp
+ *   PID params     : G_d = 0x15400000
+ *                    G_p = 0x00233333
+ *                    G_r = 0x000002fd
+ *                    History = 2 entries
+ *                    Input target = 0x3a0000
+ *                    Interval = 5s
+ *   linear-factors : offset = 0x0000 scale  = 0x1000
+ *                    offset = 0x0091 scale  = 0x0bae
+ *
+ * CPU Fan control loop. The loop is identical for all models. it
+ * has an additional pair of scaling factor. This is used to scale the
+ * systems fan control loop target result (the one before it gets scaled
+ * by the System Fans control loop itself). Then, the max value of the
+ * calculated target value and system fan value is sent to the fans
+ *
+ *   controls       : cpu-fan
+ *   sensors        : cpu-temp cpu-power
+ *   PID params     : From SMU sdb partition
+ *   linear-factors : offset = 0xfb50 scale  = 0x1000
+ *
+ * CPU Slew control loop. Not implemented. The cpufreq driver in linux is
+ * completely separate for now, though we could find a way to link it, either
+ * as a client reacting to overtemp notifications, or directling monitoring
+ * the CPU temperature
+ *
+ * WARNING ! The CPU control loop requires the CPU tmax for the current
+ * operating point. However, we currently are completely separated from
+ * the cpufreq driver and thus do not know what the current operating
+ * point is. Fortunately, we also do not have any hardware supporting anything
+ * but operating point 0 at the moment, thus we just peek that value directly
+ * from the SDB partition. If we ever end up with actually slewing the system
+ * clock and thus changing operating points, we'll have to find a way to
+ * communicate with the CPU freq driver;
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+#include <linux/kmod.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+#include <asm/io.h>
+#include <asm/system.h>
+#include <asm/sections.h>
+#include <asm/smu.h>
+
+#include "windfarm.h"
+#include "windfarm_pid.h"
+
+#define VERSION "0.4"
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define DBG(args...)	printk(args)
+#else
+#define DBG(args...)	do { } while(0)
+#endif
+
+/* define this to force CPU overtemp to 74 degree, useful for testing
+ * the overtemp code
+ */
+#undef HACKED_OVERTEMP
+
+static int wf_smu_mach_model;	/* machine model id */
+
+static struct device *wf_smu_dev;
+
+/* Controls & sensors */
+static struct wf_sensor	*sensor_cpu_power;
+static struct wf_sensor	*sensor_cpu_temp;
+static struct wf_sensor	*sensor_hd_temp;
+static struct wf_control *fan_cpu_main;
+static struct wf_control *fan_hd;
+static struct wf_control *fan_system;
+static struct wf_control *cpufreq_clamp;
+
+/* Set to kick the control loop into life */
+static int wf_smu_all_controls_ok, wf_smu_all_sensors_ok, wf_smu_started;
+
+/* Failure handling.. could be nicer */
+#define FAILURE_FAN		0x01
+#define FAILURE_SENSOR		0x02
+#define FAILURE_OVERTEMP	0x04
+
+static unsigned int wf_smu_failure_state;
+static int wf_smu_readjust, wf_smu_skipping;
+
+/*
+ * ****** System Fans Control Loop ******
+ *
+ */
+
+/* Parameters for the System Fans control loop. Parameters
+ * not in this table such as interval, history size, ...
+ * are common to all versions and thus hard coded for now.
+ */
+struct wf_smu_sys_fans_param {
+	int	model_id;
+	s32	itarget;
+	s32	gd, gp, gr;
+
+	s16	offset0;
+	u16	scale0;
+	s16	offset1;
+	u16	scale1;
+};
+
+#define WF_SMU_SYS_FANS_INTERVAL	5
+#define WF_SMU_SYS_FANS_HISTORY_SIZE	2
+
+/* State data used by the system fans control loop
+ */
+struct wf_smu_sys_fans_state {
+	int			ticks;
+	s32			sys_setpoint;
+	s32			hd_setpoint;
+	s16			offset0;
+	u16			scale0;
+	s16			offset1;
+	u16			scale1;
+	struct wf_pid_state	pid;
+};
+
+/*
+ * Configs for SMU Sytem Fan control loop
+ */
+static struct wf_smu_sys_fans_param wf_smu_sys_all_params[] = {
+	/* Model ID 2 */
+	{
+		.model_id	= 2,
+		.itarget	= 0x3a0000,
+		.gd		= 0x15400000,
+		.gp		= 0x00200000,
+		.gr		= 0x000002fd,
+		.offset0	= 0xff38,
+		.scale0		= 0x0ccd,
+		.offset1	= 0x0208,
+		.scale1		= 0x07ae,
+	},
+	/* Model ID 3 */
+	{
+		.model_id	= 2,
+		.itarget	= 0x350000,
+		.gd		= 0x08e00000,
+		.gp		= 0x00566666,
+		.gr		= 0x0000072b,
+		.offset0	= 0xff38,
+		.scale0		= 0x0ccd,
+		.offset1	= 0x0000,
+		.scale1		= 0x0000,
+	},
+	/* Model ID 5 */
+	{
+		.model_id	= 2,
+		.itarget	= 0x3a0000,
+		.gd		= 0x15400000,
+		.gp		= 0x00233333,
+		.gr		= 0x000002fd,
+		.offset0	= 0x0000,
+		.scale0		= 0x1000,
+		.offset1	= 0x0091,
+		.scale1		= 0x0bae,
+	},
+};
+#define WF_SMU_SYS_FANS_NUM_CONFIGS ARRAY_SIZE(wf_smu_sys_all_params)
+
+static struct wf_smu_sys_fans_state *wf_smu_sys_fans;
+
+/*
+ * ****** CPU Fans Control Loop ******
+ *
+ */
+
+
+#define WF_SMU_CPU_FANS_INTERVAL	1
+#define WF_SMU_CPU_FANS_MAX_HISTORY	16
+#define WF_SMU_CPU_FANS_SIBLING_SCALE	0x00001000
+#define WF_SMU_CPU_FANS_SIBLING_OFFSET	0xfffffb50
+
+/* State data used by the cpu fans control loop
+ */
+struct wf_smu_cpu_fans_state {
+	int			ticks;
+	s32			cpu_setpoint;
+	s32			scale;
+	s32			offset;
+	struct wf_cpu_pid_state	pid;
+};
+
+static struct wf_smu_cpu_fans_state *wf_smu_cpu_fans;
+
+
+
+/*
+ * ***** Implementation *****
+ *
+ */
+
+static void wf_smu_create_sys_fans(void)
+{
+	struct wf_smu_sys_fans_param *param = NULL;
+	struct wf_pid_param pid_param;
+	int i;
+
+	/* First, locate the params for this model */
+	for (i = 0; i < WF_SMU_SYS_FANS_NUM_CONFIGS; i++)
+		if (wf_smu_sys_all_params[i].model_id == wf_smu_mach_model) {
+			param = &wf_smu_sys_all_params[i];
+			break;
+		}
+
+	/* No params found, put fans to max */
+	if (param == NULL) {
+		printk(KERN_WARNING "windfarm: System fan config not found "
+		       "for this machine model, max fan speed\n");
+		goto fail;
+	}
+
+	/* Alloc & initialize state */
+	wf_smu_sys_fans = kmalloc(sizeof(struct wf_smu_sys_fans_state),
+				  GFP_KERNEL);
+	if (wf_smu_sys_fans == NULL) {
+		printk(KERN_WARNING "windfarm: Memory allocation error"
+		       " max fan speed\n");
+		goto fail;
+	}
+	wf_smu_sys_fans->ticks = 1;
+	wf_smu_sys_fans->scale0 = param->scale0;
+	wf_smu_sys_fans->offset0 = param->offset0;
+	wf_smu_sys_fans->scale1 = param->scale1;
+	wf_smu_sys_fans->offset1 = param->offset1;
+
+	/* Fill PID params */
+	pid_param.gd = param->gd;
+	pid_param.gp = param->gp;
+	pid_param.gr = param->gr;
+	pid_param.interval = WF_SMU_SYS_FANS_INTERVAL;
+	pid_param.history_len = WF_SMU_SYS_FANS_HISTORY_SIZE;
+	pid_param.itarget = param->itarget;
+	pid_param.min = fan_system->ops->get_min(fan_system);
+	pid_param.max = fan_system->ops->get_max(fan_system);
+	if (fan_hd) {
+		pid_param.min =
+			max(pid_param.min,fan_hd->ops->get_min(fan_hd));
+		pid_param.max =
+			min(pid_param.max,fan_hd->ops->get_max(fan_hd));
+	}
+	wf_pid_init(&wf_smu_sys_fans->pid, &pid_param);
+
+	DBG("wf: System Fan control initialized.\n");
+	DBG("    itarged=%d.%03d, min=%d RPM, max=%d RPM\n",
+	    FIX32TOPRINT(pid_param.itarget), pid_param.min, pid_param.max);
+	return;
+
+ fail:
+
+	if (fan_system)
+		wf_control_set_max(fan_system);
+	if (fan_hd)
+		wf_control_set_max(fan_hd);
+}
+
+static void wf_smu_sys_fans_tick(struct wf_smu_sys_fans_state *st)
+{
+	s32 new_setpoint, temp, scaled, cputarget;
+	int rc;
+
+	if (--st->ticks != 0) {
+		if (wf_smu_readjust)
+			goto readjust;
+		return;
+	}
+	st->ticks = WF_SMU_SYS_FANS_INTERVAL;
+
+	rc = sensor_hd_temp->ops->get_value(sensor_hd_temp, &temp);
+	if (rc) {
+		printk(KERN_WARNING "windfarm: HD temp sensor error %d\n",
+		       rc);
+		wf_smu_failure_state |= FAILURE_SENSOR;
+		return;
+	}
+
+	DBG("wf_smu: System Fans tick ! HD temp: %d.%03d\n",
+	    FIX32TOPRINT(temp));
+
+	if (temp > (st->pid.param.itarget + 0x50000))
+		wf_smu_failure_state |= FAILURE_OVERTEMP;
+
+	new_setpoint = wf_pid_run(&st->pid, temp);
+
+	DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint);
+
+	scaled = ((((s64)new_setpoint) * (s64)st->scale0) >> 12) + st->offset0;
+
+	DBG("wf_smu: scaled setpoint: %d RPM\n", (int)scaled);
+
+	cputarget = wf_smu_cpu_fans ? wf_smu_cpu_fans->pid.target : 0;
+	cputarget = ((((s64)cputarget) * (s64)st->scale1) >> 12) + st->offset1;
+	scaled = max(scaled, cputarget);
+	scaled = max(scaled, st->pid.param.min);
+	scaled = min(scaled, st->pid.param.max);
+
+	DBG("wf_smu: adjusted setpoint: %d RPM\n", (int)scaled);
+
+	if (st->sys_setpoint == scaled && new_setpoint == st->hd_setpoint)
+		return;
+	st->sys_setpoint = scaled;
+	st->hd_setpoint = new_setpoint;
+ readjust:
+	if (fan_system && wf_smu_failure_state == 0) {
+		rc = fan_system->ops->set_value(fan_system, st->sys_setpoint);
+		if (rc) {
+			printk(KERN_WARNING "windfarm: Sys fan error %d\n",
+			       rc);
+			wf_smu_failure_state |= FAILURE_FAN;
+		}
+	}
+	if (fan_hd && wf_smu_failure_state == 0) {
+		rc = fan_hd->ops->set_value(fan_hd, st->hd_setpoint);
+		if (rc) {
+			printk(KERN_WARNING "windfarm: HD fan error %d\n",
+			       rc);
+			wf_smu_failure_state |= FAILURE_FAN;
+		}
+	}
+}
+
+static void wf_smu_create_cpu_fans(void)
+{
+	struct wf_cpu_pid_param pid_param;
+	struct smu_sdbp_header *hdr;
+	struct smu_sdbp_cpupiddata *piddata;
+	struct smu_sdbp_fvt *fvt;
+	s32 tmax, tdelta, maxpow, powadj;
+
+	/* First, locate the PID params in SMU SBD */
+	hdr = smu_get_sdb_partition(SMU_SDB_CPUPIDDATA_ID, NULL);
+	if (hdr == 0) {
+		printk(KERN_WARNING "windfarm: CPU PID fan config not found "
+		       "max fan speed\n");
+		goto fail;
+	}
+	piddata = (struct smu_sdbp_cpupiddata *)&hdr[1];
+
+	/* Get the FVT params for operating point 0 (the only supported one
+	 * for now) in order to get tmax
+	 */
+	hdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
+	if (hdr) {
+		fvt = (struct smu_sdbp_fvt *)&hdr[1];
+		tmax = ((s32)fvt->maxtemp) << 16;
+	} else
+		tmax = 0x5e0000; /* 94 degree default */
+
+	/* Alloc & initialize state */
+	wf_smu_cpu_fans = kmalloc(sizeof(struct wf_smu_cpu_fans_state),
+				  GFP_KERNEL);
+	if (wf_smu_cpu_fans == NULL)
+		goto fail;
+       	wf_smu_cpu_fans->ticks = 1;
+
+	wf_smu_cpu_fans->scale = WF_SMU_CPU_FANS_SIBLING_SCALE;
+	wf_smu_cpu_fans->offset = WF_SMU_CPU_FANS_SIBLING_OFFSET;
+
+	/* Fill PID params */
+	pid_param.interval = WF_SMU_CPU_FANS_INTERVAL;
+	pid_param.history_len = piddata->history_len;
+	if (pid_param.history_len > WF_CPU_PID_MAX_HISTORY) {
+		printk(KERN_WARNING "windfarm: History size overflow on "
+		       "CPU control loop (%d)\n", piddata->history_len);
+		pid_param.history_len = WF_CPU_PID_MAX_HISTORY;
+	}
+	pid_param.gd = piddata->gd;
+	pid_param.gp = piddata->gp;
+	pid_param.gr = piddata->gr / pid_param.history_len;
+
+	tdelta = ((s32)piddata->target_temp_delta) << 16;
+	maxpow = ((s32)piddata->max_power) << 16;
+	powadj = ((s32)piddata->power_adj) << 16;
+
+	pid_param.tmax = tmax;
+	pid_param.ttarget = tmax - tdelta;
+	pid_param.pmaxadj = maxpow - powadj;
+
+	pid_param.min = fan_cpu_main->ops->get_min(fan_cpu_main);
+	pid_param.max = fan_cpu_main->ops->get_max(fan_cpu_main);
+
+	wf_cpu_pid_init(&wf_smu_cpu_fans->pid, &pid_param);
+
+	DBG("wf: CPU Fan control initialized.\n");
+	DBG("    ttarged=%d.%03d, tmax=%d.%03d, min=%d RPM, max=%d RPM\n",
+	    FIX32TOPRINT(pid_param.ttarget), FIX32TOPRINT(pid_param.tmax),
+	    pid_param.min, pid_param.max);
+
+	return;
+
+ fail:
+	printk(KERN_WARNING "windfarm: CPU fan config not found\n"
+	       "for this machine model, max fan speed\n");
+
+	if (cpufreq_clamp)
+		wf_control_set_max(cpufreq_clamp);
+	if (fan_cpu_main)
+		wf_control_set_max(fan_cpu_main);
+}
+
+static void wf_smu_cpu_fans_tick(struct wf_smu_cpu_fans_state *st)
+{
+	s32 new_setpoint, temp, power, systarget;
+	int rc;
+
+	if (--st->ticks != 0) {
+		if (wf_smu_readjust)
+			goto readjust;
+		return;
+	}
+	st->ticks = WF_SMU_CPU_FANS_INTERVAL;
+
+	rc = sensor_cpu_temp->ops->get_value(sensor_cpu_temp, &temp);
+	if (rc) {
+		printk(KERN_WARNING "windfarm: CPU temp sensor error %d\n",
+		       rc);
+		wf_smu_failure_state |= FAILURE_SENSOR;
+		return;
+	}
+
+	rc = sensor_cpu_power->ops->get_value(sensor_cpu_power, &power);
+	if (rc) {
+		printk(KERN_WARNING "windfarm: CPU power sensor error %d\n",
+		       rc);
+		wf_smu_failure_state |= FAILURE_SENSOR;
+		return;
+	}
+
+	DBG("wf_smu: CPU Fans tick ! CPU temp: %d.%03d, power: %d.%03d\n",
+	    FIX32TOPRINT(temp), FIX32TOPRINT(power));
+
+#ifdef HACKED_OVERTEMP
+	if (temp > 0x4a0000)
+		wf_smu_failure_state |= FAILURE_OVERTEMP;
+#else
+	if (temp > st->pid.param.tmax)
+		wf_smu_failure_state |= FAILURE_OVERTEMP;
+#endif
+	new_setpoint = wf_cpu_pid_run(&st->pid, power, temp);
+
+	DBG("wf_smu: new_setpoint: %d RPM\n", (int)new_setpoint);
+
+	systarget = wf_smu_sys_fans ? wf_smu_sys_fans->pid.target : 0;
+	systarget = ((((s64)systarget) * (s64)st->scale) >> 12)
+		+ st->offset;
+	new_setpoint = max(new_setpoint, systarget);
+	new_setpoint = max(new_setpoint, st->pid.param.min);
+	new_setpoint = min(new_setpoint, st->pid.param.max);
+
+	DBG("wf_smu: adjusted setpoint: %d RPM\n", (int)new_setpoint);
+
+	if (st->cpu_setpoint == new_setpoint)
+		return;
+	st->cpu_setpoint = new_setpoint;
+ readjust:
+	if (fan_cpu_main && wf_smu_failure_state == 0) {
+		rc = fan_cpu_main->ops->set_value(fan_cpu_main,
+						  st->cpu_setpoint);
+		if (rc) {
+			printk(KERN_WARNING "windfarm: CPU main fan"
+			       " error %d\n", rc);
+			wf_smu_failure_state |= FAILURE_FAN;
+		}
+	}
+}
+
+
+/*
+ * ****** Attributes ******
+ *
+ */
+
+#define BUILD_SHOW_FUNC_FIX(name, data)				\
+static ssize_t show_##name(struct device *dev,                  \
+			   struct device_attribute *attr,       \
+			   char *buf)	                        \
+{								\
+	ssize_t r;						\
+	s32 val = 0;                                            \
+	data->ops->get_value(data, &val);                       \
+	r = sprintf(buf, "%d.%03d", FIX32TOPRINT(val)); 	\
+	return r;						\
+}                                                               \
+static DEVICE_ATTR(name,S_IRUGO,show_##name, NULL);
+
+
+#define BUILD_SHOW_FUNC_INT(name, data)				\
+static ssize_t show_##name(struct device *dev,                  \
+			   struct device_attribute *attr,       \
+			   char *buf)	                        \
+{								\
+	s32 val = 0;                                            \
+	data->ops->get_value(data, &val);                       \
+	return sprintf(buf, "%d", val);  			\
+}                                                               \
+static DEVICE_ATTR(name,S_IRUGO,show_##name, NULL);
+
+BUILD_SHOW_FUNC_INT(cpu_fan, fan_cpu_main);
+BUILD_SHOW_FUNC_INT(sys_fan, fan_system);
+BUILD_SHOW_FUNC_INT(hd_fan, fan_hd);
+
+BUILD_SHOW_FUNC_FIX(cpu_temp, sensor_cpu_temp);
+BUILD_SHOW_FUNC_FIX(cpu_power, sensor_cpu_power);
+BUILD_SHOW_FUNC_FIX(hd_temp, sensor_hd_temp);
+
+/*
+ * ****** Setup / Init / Misc ... ******
+ *
+ */
+
+static void wf_smu_tick(void)
+{
+	unsigned int last_failure = wf_smu_failure_state;
+	unsigned int new_failure;
+
+	if (!wf_smu_started) {
+		DBG("wf: creating control loops !\n");
+		wf_smu_create_sys_fans();
+		wf_smu_create_cpu_fans();
+		wf_smu_started = 1;
+	}
+
+	/* Skipping ticks */
+	if (wf_smu_skipping && --wf_smu_skipping)
+		return;
+
+	wf_smu_failure_state = 0;
+	if (wf_smu_sys_fans)
+		wf_smu_sys_fans_tick(wf_smu_sys_fans);
+	if (wf_smu_cpu_fans)
+		wf_smu_cpu_fans_tick(wf_smu_cpu_fans);
+
+	wf_smu_readjust = 0;
+	new_failure = wf_smu_failure_state & ~last_failure;
+
+	/* If entering failure mode, clamp cpufreq and ramp all
+	 * fans to full speed.
+	 */
+	if (wf_smu_failure_state && !last_failure) {
+		if (cpufreq_clamp)
+			wf_control_set_max(cpufreq_clamp);
+		if (fan_system)
+			wf_control_set_max(fan_system);
+		if (fan_cpu_main)
+			wf_control_set_max(fan_cpu_main);
+		if (fan_hd)
+			wf_control_set_max(fan_hd);
+	}
+
+	/* If leaving failure mode, unclamp cpufreq and readjust
+	 * all fans on next iteration
+	 */
+	if (!wf_smu_failure_state && last_failure) {
+		if (cpufreq_clamp)
+			wf_control_set_min(cpufreq_clamp);
+		wf_smu_readjust = 1;
+	}
+
+	/* Overtemp condition detected, notify and start skipping a couple
+	 * ticks to let the temperature go down
+	 */
+	if (new_failure & FAILURE_OVERTEMP) {
+		wf_set_overtemp();
+		wf_smu_skipping = 2;
+	}
+
+	/* We only clear the overtemp condition if overtemp is cleared
+	 * _and_ no other failure is present. Since a sensor error will
+	 * clear the overtemp condition (can't measure temperature) at
+	 * the control loop levels, but we don't want to keep it clear
+	 * here in this case
+	 */
+	if (new_failure == 0 && last_failure & FAILURE_OVERTEMP)
+		wf_clear_overtemp();
+}
+
+static void wf_smu_new_control(struct wf_control *ct)
+{
+	if (wf_smu_all_controls_ok)
+		return;
+
+	if (fan_cpu_main == NULL && !strcmp(ct->name, "cpu-fan")) {
+		if (wf_get_control(ct) == 0) {
+			fan_cpu_main = ct;
+			device_create_file(wf_smu_dev, &dev_attr_cpu_fan);
+		}
+	}
+
+	if (fan_system == NULL && !strcmp(ct->name, "system-fan")) {
+		if (wf_get_control(ct) == 0) {
+			fan_system = ct;
+			device_create_file(wf_smu_dev, &dev_attr_sys_fan);
+		}
+	}
+
+	if (cpufreq_clamp == NULL && !strcmp(ct->name, "cpufreq-clamp")) {
+		if (wf_get_control(ct) == 0)
+			cpufreq_clamp = ct;
+	}
+
+	/* Darwin property list says the HD fan is only for model ID
+	 * 0, 1, 2 and 3
+	 */
+
+	if (wf_smu_mach_model > 3) {
+		if (fan_system && fan_cpu_main && cpufreq_clamp)
+			wf_smu_all_controls_ok = 1;
+		return;
+	}
+
+	if (fan_hd == NULL && !strcmp(ct->name, "drive-bay-fan")) {
+		if (wf_get_control(ct) == 0) {
+			fan_hd = ct;
+			device_create_file(wf_smu_dev, &dev_attr_hd_fan);
+		}
+	}
+
+	if (fan_system && fan_hd && fan_cpu_main && cpufreq_clamp)
+		wf_smu_all_controls_ok = 1;
+}
+
+static void wf_smu_new_sensor(struct wf_sensor *sr)
+{
+	if (wf_smu_all_sensors_ok)
+		return;
+
+	if (sensor_cpu_power == NULL && !strcmp(sr->name, "cpu-power")) {
+		if (wf_get_sensor(sr) == 0) {
+			sensor_cpu_power = sr;
+			device_create_file(wf_smu_dev, &dev_attr_cpu_power);
+		}
+	}
+
+	if (sensor_cpu_temp == NULL && !strcmp(sr->name, "cpu-temp")) {
+		if (wf_get_sensor(sr) == 0) {
+			sensor_cpu_temp = sr;
+			device_create_file(wf_smu_dev, &dev_attr_cpu_temp);
+		}
+	}
+
+	if (sensor_hd_temp == NULL && !strcmp(sr->name, "hd-temp")) {
+		if (wf_get_sensor(sr) == 0) {
+			sensor_hd_temp = sr;
+			device_create_file(wf_smu_dev, &dev_attr_hd_temp);
+		}
+	}
+
+	if (sensor_cpu_power && sensor_cpu_temp && sensor_hd_temp)
+		wf_smu_all_sensors_ok = 1;
+}
+
+
+static int wf_smu_notify(struct notifier_block *self,
+			       unsigned long event, void *data)
+{
+	switch(event) {
+	case WF_EVENT_NEW_CONTROL:
+		DBG("wf: new control %s detected\n",
+		    ((struct wf_control *)data)->name);
+		wf_smu_new_control(data);
+		wf_smu_readjust = 1;
+		break;
+	case WF_EVENT_NEW_SENSOR:
+		DBG("wf: new sensor %s detected\n",
+		    ((struct wf_sensor *)data)->name);
+		wf_smu_new_sensor(data);
+		break;
+	case WF_EVENT_TICK:
+		if (wf_smu_all_controls_ok && wf_smu_all_sensors_ok)
+			wf_smu_tick();
+	}
+
+	return 0;
+}
+
+static struct notifier_block wf_smu_events = {
+	.notifier_call	= wf_smu_notify,
+};
+
+static int wf_init_pm(void)
+{
+	struct smu_sdbp_header *hdr;
+
+	hdr = smu_get_sdb_partition(SMU_SDB_SENSORTREE_ID, NULL);
+	if (hdr != 0) {
+		struct smu_sdbp_sensortree *st =
+			(struct smu_sdbp_sensortree *)&hdr[1];
+		wf_smu_mach_model = st->model_id;
+	}
+
+	printk(KERN_INFO "windfarm: Initializing for iMacG5 model ID %d\n",
+	       wf_smu_mach_model);
+
+	return 0;
+}
+
+static int wf_smu_probe(struct device *ddev)
+{
+	wf_smu_dev = ddev;
+
+	wf_register_client(&wf_smu_events);
+
+	return 0;
+}
+
+static int wf_smu_remove(struct device *ddev)
+{
+	wf_unregister_client(&wf_smu_events);
+
+	/* XXX We don't have yet a guarantee that our callback isn't
+	 * in progress when returning from wf_unregister_client, so
+	 * we add an arbitrary delay. I'll have to fix that in the core
+	 */
+	msleep(1000);
+
+	/* Release all sensors */
+	/* One more crappy race: I don't think we have any guarantee here
+	 * that the attribute callback won't race with the sensor beeing
+	 * disposed of, and I'm not 100% certain what best way to deal
+	 * with that except by adding locks all over... I'll do that
+	 * eventually but heh, who ever rmmod this module anyway ?
+	 */
+	if (sensor_cpu_power) {
+		device_remove_file(wf_smu_dev, &dev_attr_cpu_power);
+		wf_put_sensor(sensor_cpu_power);
+	}
+	if (sensor_cpu_temp) {
+		device_remove_file(wf_smu_dev, &dev_attr_cpu_temp);
+		wf_put_sensor(sensor_cpu_temp);
+	}
+	if (sensor_hd_temp) {
+		device_remove_file(wf_smu_dev, &dev_attr_hd_temp);
+		wf_put_sensor(sensor_hd_temp);
+	}
+
+	/* Release all controls */
+	if (fan_cpu_main) {
+		device_remove_file(wf_smu_dev, &dev_attr_cpu_fan);
+		wf_put_control(fan_cpu_main);
+	}
+	if (fan_hd) {
+		device_remove_file(wf_smu_dev, &dev_attr_hd_fan);
+		wf_put_control(fan_hd);
+	}
+	if (fan_system) {
+		device_remove_file(wf_smu_dev, &dev_attr_sys_fan);
+		wf_put_control(fan_system);
+	}
+	if (cpufreq_clamp)
+		wf_put_control(cpufreq_clamp);
+
+	/* Destroy control loops state structures */
+	if (wf_smu_sys_fans)
+		kfree(wf_smu_sys_fans);
+	if (wf_smu_cpu_fans)
+		kfree(wf_smu_cpu_fans);
+
+	wf_smu_dev = NULL;
+
+	return 0;
+}
+
+static struct device_driver wf_smu_driver = {
+        .name = "windfarm",
+        .bus = &platform_bus_type,
+        .probe = wf_smu_probe,
+        .remove = wf_smu_remove,
+};
+
+
+static int __init wf_smu_init(void)
+{
+	int rc = -ENODEV;
+
+	if (machine_is_compatible("PowerMac8,1") ||
+	    machine_is_compatible("PowerMac8,2"))
+		rc = wf_init_pm();
+
+	if (rc == 0) {
+#ifdef MODULE
+		request_module("windfarm_smu_controls");
+		request_module("windfarm_smu_sensors");
+		request_module("windfarm_lm75_sensor");
+
+#endif /* MODULE */
+		driver_register(&wf_smu_driver);
+	}
+
+	return rc;
+}
+
+static void __exit wf_smu_exit(void)
+{
+
+	driver_unregister(&wf_smu_driver);
+}
+
+
+module_init(wf_smu_init);
+module_exit(wf_smu_exit);
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("Thermal control logic for iMac G5");
+MODULE_LICENSE("GPL");
+