windfarm_pm112.c

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/*
 * Windfarm PowerMac thermal control.
 * Control loops for machines with SMU and PPC970MP processors.
 *
 * Copyright (C) 2005 Paul Mackerras, IBM Corp. <[e-mail]>
 * 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)