Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / macintosh / windfarm_rm31.c
diff --git a/kernel/drivers/macintosh/windfarm_rm31.c b/kernel/drivers/macintosh/windfarm_rm31.c
new file mode 100644 (file)
index 0000000..82fc86a
--- /dev/null
@@ -0,0 +1,740 @@
+/*
+ * Windfarm PowerMac thermal control.
+ * Control loops for RackMack3,1 (Xserve G5)
+ *
+ * Copyright (C) 2012 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"
+#include "windfarm_mpu.h"
+
+#define VERSION "1.0"
+
+#undef 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 */
+#define NR_CHIPS       2
+#define NR_CPU_FANS    3 * NR_CHIPS
+
+/* Controls and sensors */
+static struct wf_sensor *sens_cpu_temp[NR_CHIPS];
+static struct wf_sensor *sens_cpu_volts[NR_CHIPS];
+static struct wf_sensor *sens_cpu_amps[NR_CHIPS];
+static struct wf_sensor *backside_temp;
+static struct wf_sensor *slots_temp;
+static struct wf_sensor *dimms_temp;
+
+static struct wf_control *cpu_fans[NR_CHIPS][3];
+static struct wf_control *backside_fan;
+static struct wf_control *slots_fan;
+static struct wf_control *cpufreq_clamp;
+
+/* We keep a temperature history for average calculation of 180s */
+#define CPU_TEMP_HIST_SIZE     180
+
+/* PID loop state */
+static const struct mpu_data *cpu_mpu_data[NR_CHIPS];
+static struct wf_cpu_pid_state cpu_pid[NR_CHIPS];
+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 struct wf_pid_state backside_pid;
+static int backside_tick;
+static struct wf_pid_state slots_pid;
+static int slots_tick;
+static int slots_speed;
+static struct wf_pid_state dimms_pid;
+static int dimms_output_clamp;
+
+static int nr_chips;
+static bool have_all_controls;
+static bool have_all_sensors;
+static bool 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)
+
+
+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_chips; i++) {
+               if (cpu_fans[i][0])
+                       wf_control_set_max(cpu_fans[i][0]);
+               if (cpu_fans[i][1])
+                       wf_control_set_max(cpu_fans[i][1]);
+               if (cpu_fans[i][2])
+                       wf_control_set_max(cpu_fans[i][2]);
+       }
+}
+
+static int cpu_check_overtemp(s32 temp)
+{
+       int new_state = 0;
+       s32 t_avg, t_old;
+       static bool first = true;
+
+       /* 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");
+       }
+
+       /*
+        * The first time around, initialize the array with the first
+        * temperature reading
+        */
+       if (first) {
+               int i;
+
+               cpu_thist_total = 0;
+               for (i = 0; i < CPU_TEMP_HIST_SIZE; i++) {
+                       cpu_thist[i] = temp;
+                       cpu_thist_total += temp;
+               }
+               first = false;
+       }
+
+       /*
+        * 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 int read_one_cpu_vals(int cpu, s32 *temp, s32 *power)
+{
+       s32 dtemp, volts, amps;
+       int rc;
+
+       /* Get diode temperature */
+       rc = wf_sensor_get(sens_cpu_temp[cpu], &dtemp);
+       if (rc) {
+               DBG("  CPU%d: temp reading error !\n", cpu);
+               return -EIO;
+       }
+       DBG_LOTS("  CPU%d: temp   = %d.%03d\n", cpu, FIX32TOPRINT((dtemp)));
+       *temp = dtemp;
+
+       /* Get voltage */
+       rc = wf_sensor_get(sens_cpu_volts[cpu], &volts);
+       if (rc) {
+               DBG("  CPU%d, volts reading error !\n", cpu);
+               return -EIO;
+       }
+       DBG_LOTS("  CPU%d: volts  = %d.%03d\n", cpu, FIX32TOPRINT((volts)));
+
+       /* Get current */
+       rc = wf_sensor_get(sens_cpu_amps[cpu], &amps);
+       if (rc) {
+               DBG("  CPU%d, current reading error !\n", cpu);
+               return -EIO;
+       }
+       DBG_LOTS("  CPU%d: amps   = %d.%03d\n", cpu, FIX32TOPRINT((amps)));
+
+       /* Calculate power */
+
+       /* Scale voltage and current raw sensor values according to fixed scales
+        * obtained in Darwin and calculate power from I and V
+        */
+       *power = (((u64)volts) * ((u64)amps)) >> 16;
+
+       DBG_LOTS("  CPU%d: power  = %d.%03d\n", cpu, FIX32TOPRINT((*power)));
+
+       return 0;
+
+}
+
+static void cpu_fans_tick(void)
+{
+       int err, cpu, i;
+       s32 speed, temp, power, t_max = 0;
+
+       DBG_LOTS("* cpu fans_tick_split()\n");
+
+       for (cpu = 0; cpu < nr_chips; ++cpu) {
+               struct wf_cpu_pid_state *sp = &cpu_pid[cpu];
+
+               /* Read current speed */
+               wf_control_get(cpu_fans[cpu][0], &sp->target);
+
+               err = read_one_cpu_vals(cpu, &temp, &power);
+               if (err) {
+                       failure_state |= FAILURE_SENSOR;
+                       cpu_max_all_fans();
+                       return;
+               }
+
+               /* Keep track of highest temp */
+               t_max = max(t_max, temp);
+
+               /* Handle possible overtemps */
+               if (cpu_check_overtemp(t_max))
+                       return;
+
+               /* Run PID */
+               wf_cpu_pid_run(sp, power, temp);
+
+               DBG_LOTS("  CPU%d: target = %d RPM\n", cpu, sp->target);
+
+               /* Apply DIMMs clamp */
+               speed = max(sp->target, dimms_output_clamp);
+
+               /* Apply result to all cpu fans */
+               for (i = 0; i < 3; i++) {
+                       err = wf_control_set(cpu_fans[cpu][i], speed);
+                       if (err) {
+                               pr_warning("wf_rm31: Fan %s reports error %d\n",
+                                          cpu_fans[cpu][i]->name, err);
+                               failure_state |= FAILURE_FAN;
+                       }
+               }
+       }
+}
+
+/* Implementation... */
+static int cpu_setup_pid(int cpu)
+{
+       struct wf_cpu_pid_param pid;
+       const struct mpu_data *mpu = cpu_mpu_data[cpu];
+       s32 tmax, ttarget, ptarget;
+       int fmin, fmax, hsize;
+
+       /* Get PID params from the appropriate MPU EEPROM */
+       tmax = mpu->tmax << 16;
+       ttarget = mpu->ttarget << 16;
+       ptarget = ((s32)(mpu->pmaxh - mpu->padjmax)) << 16;
+
+       DBG("wf_72: CPU%d ttarget = %d.%03d, tmax = %d.%03d\n",
+           cpu, FIX32TOPRINT(ttarget), FIX32TOPRINT(tmax));
+
+       /* We keep a global tmax for overtemp calculations */
+       if (tmax < cpu_all_tmax)
+               cpu_all_tmax = tmax;
+
+       /* Set PID min/max by using the rear fan min/max */
+       fmin = wf_control_get_min(cpu_fans[cpu][0]);
+       fmax = wf_control_get_max(cpu_fans[cpu][0]);
+       DBG("wf_72: CPU%d max RPM range = [%d..%d]\n", cpu, fmin, fmax);
+
+       /* History size */
+       hsize = min_t(int, mpu->tguardband, WF_PID_MAX_HISTORY);
+       DBG("wf_72: CPU%d history size = %d\n", cpu, hsize);
+
+       /* Initialize PID loop */
+       pid.interval    = 1;    /* seconds */
+       pid.history_len = hsize;
+       pid.gd          = mpu->pid_gd;
+       pid.gp          = mpu->pid_gp;
+       pid.gr          = mpu->pid_gr;
+       pid.tmax        = tmax;
+       pid.ttarget     = ttarget;
+       pid.pmaxadj     = ptarget;
+       pid.min         = fmin;
+       pid.max         = fmax;
+
+       wf_cpu_pid_init(&cpu_pid[cpu], &pid);
+       cpu_pid[cpu].target = 4000;
+       
+       return 0;
+}
+
+/* Backside/U3 fan */
+static struct wf_pid_param backside_param = {
+       .interval       = 1,
+       .history_len    = 2,
+       .gd             = 0x00500000,
+       .gp             = 0x0004cccc,
+       .gr             = 0,
+       .itarget        = 70 << 16,
+       .additive       = 0,
+       .min            = 20,
+       .max            = 100,
+};
+
+/* DIMMs temperature (clamp the backside fan) */
+static struct wf_pid_param dimms_param = {
+       .interval       = 1,
+       .history_len    = 20,
+       .gd             = 0,
+       .gp             = 0,
+       .gr             = 0x06553600,
+       .itarget        = 50 << 16,
+       .additive       = 0,
+       .min            = 4000,
+       .max            = 14000,
+};
+
+static void backside_fan_tick(void)
+{
+       s32 temp, dtemp;
+       int speed, dspeed, fan_min;
+       int err;
+
+       if (!backside_fan || !backside_temp || !dimms_temp || !backside_tick)
+               return;
+       if (--backside_tick > 0)
+               return;
+       backside_tick = backside_pid.param.interval;
+
+       DBG_LOTS("* backside fans tick\n");
+
+       /* Update fan speed from actual fans */
+       err = wf_control_get(backside_fan, &speed);
+       if (!err)
+               backside_pid.target = speed;
+
+       err = wf_sensor_get(backside_temp, &temp);
+       if (err) {
+               printk(KERN_WARNING "windfarm: U3 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 = wf_sensor_get(dimms_temp, &dtemp);
+       if (err) {
+               printk(KERN_WARNING "windfarm: DIMMs temp sensor error %d\n",
+                      err);
+               failure_state |= FAILURE_SENSOR;
+               wf_control_set_max(backside_fan);
+               return;
+       }
+       dspeed = wf_pid_run(&dimms_pid, dtemp);
+       dimms_output_clamp = dspeed;
+
+       fan_min = (dspeed * 100) / 14000;
+       fan_min = max(fan_min, backside_param.min);
+       speed = max(speed, fan_min);
+
+       err = wf_control_set(backside_fan, speed);
+       if (err) {
+               printk(KERN_WARNING "windfarm: backside fan error %d\n", err);
+               failure_state |= FAILURE_FAN;
+       }
+}
+
+static void backside_setup_pid(void)
+{
+       /* first time initialize things */
+       s32 fmin = wf_control_get_min(backside_fan);
+       s32 fmax = wf_control_get_max(backside_fan);
+       struct wf_pid_param param;
+
+       param = backside_param;
+       param.min = max(param.min, fmin);
+       param.max = min(param.max, fmax);
+       wf_pid_init(&backside_pid, &param);
+
+       param = dimms_param;
+       wf_pid_init(&dimms_pid, &param);
+
+       backside_tick = 1;
+
+       pr_info("wf_rm31: Backside control loop started.\n");
+}
+
+/* Slots fan */
+static const struct wf_pid_param slots_param = {
+       .interval       = 1,
+       .history_len    = 20,
+       .gd             = 0,
+       .gp             = 0,
+       .gr             = 0x00100000,
+       .itarget        = 3200000,
+       .additive       = 0,
+       .min            = 20,
+       .max            = 100,
+};
+
+static void slots_fan_tick(void)
+{
+       s32 temp;
+       int speed;
+       int err;
+
+       if (!slots_fan || !slots_temp || !slots_tick)
+               return;
+       if (--slots_tick > 0)
+               return;
+       slots_tick = slots_pid.param.interval;
+
+       DBG_LOTS("* slots fans tick\n");
+
+       err = wf_sensor_get(slots_temp, &temp);
+       if (err) {
+               pr_warning("wf_rm31: slots temp sensor error %d\n", err);
+               failure_state |= FAILURE_SENSOR;
+               wf_control_set_max(slots_fan);
+               return;
+       }
+       speed = wf_pid_run(&slots_pid, temp);
+
+       DBG_LOTS("slots PID temp=%d.%.3d speed=%d\n",
+                FIX32TOPRINT(temp), speed);
+
+       slots_speed = speed;
+       err = wf_control_set(slots_fan, speed);
+       if (err) {
+               printk(KERN_WARNING "windfarm: slots bay fan error %d\n", err);
+               failure_state |= FAILURE_FAN;
+       }
+}
+
+static void slots_setup_pid(void)
+{
+       /* first time initialize things */
+       s32 fmin = wf_control_get_min(slots_fan);
+       s32 fmax = wf_control_get_max(slots_fan);
+       struct wf_pid_param param = slots_param;
+
+       param.min = max(param.min, fmin);
+       param.max = min(param.max, fmax);
+       wf_pid_init(&slots_pid, &param);
+       slots_tick = 1;
+
+       pr_info("wf_rm31: Slots control loop started.\n");
+}
+
+static void set_fail_state(void)
+{
+       cpu_max_all_fans();
+
+       if (backside_fan)
+               wf_control_set_max(backside_fan);
+       if (slots_fan)
+               wf_control_set_max(slots_fan);
+}
+
+static void rm31_tick(void)
+{
+       int i, last_failure;
+
+       if (!started) {
+               started = 1;
+               printk(KERN_INFO "windfarm: CPUs control loops started.\n");
+               for (i = 0; i < nr_chips; ++i) {
+                       if (cpu_setup_pid(i) < 0) {
+                               failure_state = FAILURE_PERM;
+                               set_fail_state();
+                               break;
+                       }
+               }
+               DBG_LOTS("cpu_all_tmax=%d.%03d\n", FIX32TOPRINT(cpu_all_tmax));
+
+               backside_setup_pid();
+               slots_setup_pid();
+
+#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;
+       backside_fan_tick();
+       slots_fan_tick();
+
+       /* We do CPUs last because they can be clamped high by
+        * DIMM temperature
+        */
+       cpu_fans_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 rm31_new_control(struct wf_control *ct)
+{
+       bool all_controls;
+
+       if (!strcmp(ct->name, "cpu-fan-a-0"))
+               cpu_fans[0][0] = ct;
+       else if (!strcmp(ct->name, "cpu-fan-b-0"))
+               cpu_fans[0][1] = ct;
+       else if (!strcmp(ct->name, "cpu-fan-c-0"))
+               cpu_fans[0][2] = ct;
+       else if (!strcmp(ct->name, "cpu-fan-a-1"))
+               cpu_fans[1][0] = ct;
+       else if (!strcmp(ct->name, "cpu-fan-b-1"))
+               cpu_fans[1][1] = ct;
+       else if (!strcmp(ct->name, "cpu-fan-c-1"))
+               cpu_fans[1][2] = ct;
+       else if (!strcmp(ct->name, "backside-fan"))
+               backside_fan = ct;
+       else if (!strcmp(ct->name, "slots-fan"))
+               slots_fan = ct;
+       else if (!strcmp(ct->name, "cpufreq-clamp"))
+               cpufreq_clamp = ct;
+
+       all_controls =
+               cpu_fans[0][0] &&
+               cpu_fans[0][1] &&
+               cpu_fans[0][2] &&
+               backside_fan &&
+               slots_fan;
+       if (nr_chips > 1)
+               all_controls &=
+                       cpu_fans[1][0] &&
+                       cpu_fans[1][1] &&
+                       cpu_fans[1][2];
+       have_all_controls = all_controls;
+}
+
+
+static void rm31_new_sensor(struct wf_sensor *sr)
+{
+       bool all_sensors;
+
+       if (!strcmp(sr->name, "cpu-diode-temp-0"))
+               sens_cpu_temp[0] = sr;
+       else if (!strcmp(sr->name, "cpu-diode-temp-1"))
+               sens_cpu_temp[1] = sr;
+       else if (!strcmp(sr->name, "cpu-voltage-0"))
+               sens_cpu_volts[0] = sr;
+       else if (!strcmp(sr->name, "cpu-voltage-1"))
+               sens_cpu_volts[1] = sr;
+       else if (!strcmp(sr->name, "cpu-current-0"))
+               sens_cpu_amps[0] = sr;
+       else if (!strcmp(sr->name, "cpu-current-1"))
+               sens_cpu_amps[1] = sr;
+       else if (!strcmp(sr->name, "backside-temp"))
+               backside_temp = sr;
+       else if (!strcmp(sr->name, "slots-temp"))
+               slots_temp = sr;
+       else if (!strcmp(sr->name, "dimms-temp"))
+               dimms_temp = sr;
+
+       all_sensors =
+               sens_cpu_temp[0] &&
+               sens_cpu_volts[0] &&
+               sens_cpu_amps[0] &&
+               backside_temp &&
+               slots_temp &&
+               dimms_temp;
+       if (nr_chips > 1)
+               all_sensors &=
+                       sens_cpu_temp[1] &&
+                       sens_cpu_volts[1] &&
+                       sens_cpu_amps[1];
+
+       have_all_sensors = all_sensors;
+}
+
+static int rm31_wf_notify(struct notifier_block *self,
+                         unsigned long event, void *data)
+{
+       switch (event) {
+       case WF_EVENT_NEW_SENSOR:
+               rm31_new_sensor(data);
+               break;
+       case WF_EVENT_NEW_CONTROL:
+               rm31_new_control(data);
+               break;
+       case WF_EVENT_TICK:
+               if (have_all_controls && have_all_sensors)
+                       rm31_tick();
+       }
+       return 0;
+}
+
+static struct notifier_block rm31_events = {
+       .notifier_call = rm31_wf_notify,
+};
+
+static int wf_rm31_probe(struct platform_device *dev)
+{
+       wf_register_client(&rm31_events);
+       return 0;
+}
+
+static int wf_rm31_remove(struct platform_device *dev)
+{
+       wf_unregister_client(&rm31_events);
+
+       /* should release all sensors and controls */
+       return 0;
+}
+
+static struct platform_driver wf_rm31_driver = {
+       .probe  = wf_rm31_probe,
+       .remove = wf_rm31_remove,
+       .driver = {
+               .name = "windfarm",
+               .owner  = THIS_MODULE,
+       },
+};
+
+static int __init wf_rm31_init(void)
+{
+       struct device_node *cpu;
+       int i;
+
+       if (!of_machine_is_compatible("RackMac3,1"))
+               return -ENODEV;
+
+       /* Count the number of CPU cores */
+       nr_chips = 0;
+       for_each_node_by_type(cpu, "cpu")
+               ++nr_chips;
+       if (nr_chips > NR_CHIPS)
+               nr_chips = NR_CHIPS;
+
+       pr_info("windfarm: Initializing for desktop G5 with %d chips\n",
+               nr_chips);
+
+       /* Get MPU data for each CPU */
+       for (i = 0; i < nr_chips; i++) {
+               cpu_mpu_data[i] = wf_get_mpu(i);
+               if (!cpu_mpu_data[i]) {
+                       pr_err("wf_rm31: Failed to find MPU data for CPU %d\n", i);
+                       return -ENXIO;
+               }
+       }
+
+#ifdef MODULE
+       request_module("windfarm_fcu_controls");
+       request_module("windfarm_lm75_sensor");
+       request_module("windfarm_lm87_sensor");
+       request_module("windfarm_ad7417_sensor");
+       request_module("windfarm_max6690_sensor");
+       request_module("windfarm_cpufreq_clamp");
+#endif /* MODULE */
+
+       platform_driver_register(&wf_rm31_driver);
+       return 0;
+}
+
+static void __exit wf_rm31_exit(void)
+{
+       platform_driver_unregister(&wf_rm31_driver);
+}
+
+module_init(wf_rm31_init);
+module_exit(wf_rm31_exit);
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("Thermal control for Xserve G5");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:windfarm");