xref: /freebsd-11-stable/sys/powerpc/powermac/smu.c

/*-
 * Copyright (c) 2009 Nathan Whitehorn
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided 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.
 *
 * 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/cdefs.h>
__FBSDID("$FreeBSD: head/sys/powerpc/powermac/smu.c 232482 2012-03-04 08:43:33Z andreast $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/systm.h>
#include <sys/module.h>
#include <sys/conf.h>
#include <sys/cpu.h>
#include <sys/clock.h>
#include <sys/ctype.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/reboot.h>
#include <sys/rman.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>

#include <machine/bus.h>
#include <machine/intr_machdep.h>
#include <machine/md_var.h>

#include <dev/iicbus/iicbus.h>
#include <dev/iicbus/iiconf.h>
#include <dev/led/led.h>
#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <powerpc/powermac/macgpiovar.h>
#include <powerpc/powermac/powermac_thermal.h>

#include "clock_if.h"
#include "iicbus_if.h"

struct smu_cmd {
	volatile uint8_t cmd;
	uint8_t		len;
	uint8_t		data[254];

	STAILQ_ENTRY(smu_cmd) cmd_q;
};

STAILQ_HEAD(smu_cmdq, smu_cmd);

struct smu_fan {
	struct pmac_fan fan;
	device_t dev;
	cell_t	reg;

	enum {
		SMU_FAN_RPM,
		SMU_FAN_PWM
	} type;
	int	old_style;
	int	setpoint;
	int     rpm;
};

/* We can read the PWM and the RPM from a PWM controlled fan.
 * Offer both values via sysctl.
 */
enum {
	SMU_PWM_SYSCTL_PWM   = 1 << 8,
	SMU_PWM_SYSCTL_RPM   = 2 << 8
};

struct smu_sensor {
	struct pmac_therm therm;
	device_t dev;

	cell_t	reg;
	enum {
		SMU_CURRENT_SENSOR,
		SMU_VOLTAGE_SENSOR,
		SMU_POWER_SENSOR,
		SMU_TEMP_SENSOR
	} type;
};

struct smu_softc {
	device_t	sc_dev;
	struct mtx	sc_mtx;

	struct resource	*sc_memr;
	int		sc_memrid;
	int		sc_u3;

	bus_dma_tag_t	sc_dmatag;
	bus_space_tag_t	sc_bt;
	bus_space_handle_t sc_mailbox;

	struct smu_cmd	*sc_cmd, *sc_cur_cmd;
	bus_addr_t	sc_cmd_phys;
	bus_dmamap_t	sc_cmd_dmamap;
	struct smu_cmdq	sc_cmdq;

	struct smu_fan	*sc_fans;
	int		sc_nfans;
	struct smu_sensor *sc_sensors;
	int		sc_nsensors;

	int		sc_doorbellirqid;
	struct resource	*sc_doorbellirq;
	void		*sc_doorbellirqcookie;

	struct proc	*sc_fanmgt_proc;
	time_t		sc_lastuserchange;

	/* Calibration data */
	uint16_t	sc_cpu_diode_scale;
	int16_t		sc_cpu_diode_offset;

	uint16_t	sc_cpu_volt_scale;
	int16_t		sc_cpu_volt_offset;
	uint16_t	sc_cpu_curr_scale;
	int16_t		sc_cpu_curr_offset;

	uint16_t	sc_slots_pow_scale;
	int16_t		sc_slots_pow_offset;

	struct cdev 	*sc_leddev;
};

/* regular bus attachment functions */

static int	smu_probe(device_t);
static int	smu_attach(device_t);
static const struct ofw_bus_devinfo *
    smu_get_devinfo(device_t bus, device_t dev);

/* cpufreq notification hooks */

static void	smu_cpufreq_pre_change(device_t, const struct cf_level *level);
static void	smu_cpufreq_post_change(device_t, const struct cf_level *level);

/* clock interface */
static int	smu_gettime(device_t dev, struct timespec *ts);
static int	smu_settime(device_t dev, struct timespec *ts);

/* utility functions */
static int	smu_run_cmd(device_t dev, struct smu_cmd *cmd, int wait);
static int	smu_get_datablock(device_t dev, int8_t id, uint8_t *buf,
		    size_t len);
static void	smu_attach_i2c(device_t dev, phandle_t i2croot);
static void	smu_attach_fans(device_t dev, phandle_t fanroot);
static void	smu_attach_sensors(device_t dev, phandle_t sensroot);
static void	smu_set_sleepled(void *xdev, int onoff);
static int	smu_server_mode(SYSCTL_HANDLER_ARGS);
static void	smu_doorbell_intr(void *xdev);
static void	smu_shutdown(void *xdev, int howto);

/* where to find the doorbell GPIO */

static device_t	smu_doorbell = NULL;

static device_method_t  smu_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		smu_probe),
	DEVMETHOD(device_attach,	smu_attach),

	/* Clock interface */
	DEVMETHOD(clock_gettime,	smu_gettime),
	DEVMETHOD(clock_settime,	smu_settime),

	/* ofw_bus interface */
	DEVMETHOD(bus_child_pnpinfo_str,ofw_bus_gen_child_pnpinfo_str),
	DEVMETHOD(ofw_bus_get_devinfo,	smu_get_devinfo),
	DEVMETHOD(ofw_bus_get_compat,	ofw_bus_gen_get_compat),
	DEVMETHOD(ofw_bus_get_model,	ofw_bus_gen_get_model),
	DEVMETHOD(ofw_bus_get_name,	ofw_bus_gen_get_name),
	DEVMETHOD(ofw_bus_get_node,	ofw_bus_gen_get_node),
	DEVMETHOD(ofw_bus_get_type,	ofw_bus_gen_get_type),

	{ 0, 0 },
};

static driver_t smu_driver = {
	"smu",
	smu_methods,
	sizeof(struct smu_softc)
};

static devclass_t smu_devclass;

DRIVER_MODULE(smu, nexus, smu_driver, smu_devclass, 0, 0);
static MALLOC_DEFINE(M_SMU, "smu", "SMU Sensor Information");

#define SMU_MAILBOX		0x8000860c
#define SMU_FANMGT_INTERVAL	1000 /* ms */

/* Command types */
#define SMU_ADC			0xd8
#define SMU_FAN			0x4a
#define SMU_RPM_STATUS		0x01
#define SMU_RPM_SETPOINT	0x02
#define SMU_PWM_STATUS		0x11
#define SMU_PWM_SETPOINT	0x12
#define SMU_I2C			0x9a
#define  SMU_I2C_SIMPLE		0x00
#define  SMU_I2C_NORMAL		0x01
#define  SMU_I2C_COMBINED	0x02
#define SMU_MISC		0xee
#define  SMU_MISC_GET_DATA	0x02
#define  SMU_MISC_LED_CTRL	0x04
#define SMU_POWER		0xaa
#define SMU_POWER_EVENTS	0x8f
#define  SMU_PWR_GET_POWERUP	0x00
#define  SMU_PWR_SET_POWERUP	0x01
#define  SMU_PWR_CLR_POWERUP	0x02
#define SMU_RTC			0x8e
#define  SMU_RTC_GET		0x81
#define  SMU_RTC_SET		0x80

/* Power event types */
#define SMU_WAKEUP_KEYPRESS	0x01
#define SMU_WAKEUP_AC_INSERT	0x02
#define SMU_WAKEUP_AC_CHANGE	0x04
#define SMU_WAKEUP_RING		0x10

/* Data blocks */
#define SMU_CPUTEMP_CAL		0x18
#define SMU_CPUVOLT_CAL		0x21
#define SMU_SLOTPW_CAL		0x78

/* Partitions */
#define SMU_PARTITION		0x3e
#define SMU_PARTITION_LATEST	0x01
#define SMU_PARTITION_BASE	0x02
#define SMU_PARTITION_UPDATE	0x03

static int
smu_probe(device_t dev)
{
	const char *name = ofw_bus_get_name(dev);

	if (strcmp(name, "smu") != 0)
		return (ENXIO);

	device_set_desc(dev, "Apple System Management Unit");
	return (0);
}

static void
smu_phys_callback(void *xsc, bus_dma_segment_t *segs, int nsegs, int error)
{
	struct smu_softc *sc = xsc;

	sc->sc_cmd_phys = segs[0].ds_addr;
}

static int
smu_attach(device_t dev)
{
	struct smu_softc *sc;
	phandle_t	node, child;
	uint8_t		data[12];

	sc = device_get_softc(dev);

	mtx_init(&sc->sc_mtx, "smu", NULL, MTX_DEF);
	sc->sc_cur_cmd = NULL;
	sc->sc_doorbellirqid = -1;

	sc->sc_u3 = 0;
	if (OF_finddevice("/u3") != -1)
		sc->sc_u3 = 1;

	/*
	 * Map the mailbox area. This should be determined from firmware,
	 * but I have not found a simple way to do that.
	 */
	bus_dma_tag_create(NULL, 16, 0, BUS_SPACE_MAXADDR_32BIT,
	    BUS_SPACE_MAXADDR, NULL, NULL, PAGE_SIZE, 1, PAGE_SIZE, 0, NULL,
	    NULL, &(sc->sc_dmatag));
	sc->sc_bt = &bs_le_tag;
	bus_space_map(sc->sc_bt, SMU_MAILBOX, 4, 0, &sc->sc_mailbox);

	/*
	 * Allocate the command buffer. This can be anywhere in the low 4 GB
	 * of memory.
	 */
	bus_dmamem_alloc(sc->sc_dmatag, (void **)&sc->sc_cmd, BUS_DMA_WAITOK |
	    BUS_DMA_ZERO, &sc->sc_cmd_dmamap);
	bus_dmamap_load(sc->sc_dmatag, sc->sc_cmd_dmamap,
	    sc->sc_cmd, PAGE_SIZE, smu_phys_callback, sc, 0);
	STAILQ_INIT(&sc->sc_cmdq);

	/*
	 * Set up handlers to change CPU voltage when CPU frequency is changed.
	 */
	EVENTHANDLER_REGISTER(cpufreq_pre_change, smu_cpufreq_pre_change, dev,
	    EVENTHANDLER_PRI_ANY);
	EVENTHANDLER_REGISTER(cpufreq_post_change, smu_cpufreq_post_change, dev,
	    EVENTHANDLER_PRI_ANY);

	node = ofw_bus_get_node(dev);

	/* Some SMUs have RPM and PWM controlled fans which do not sit
	 * under the same node. So we have to attach them separately.
	 */
	smu_attach_fans(dev, node);

	/*
	 * Now detect and attach the other child devices.
	 */
	for (child = OF_child(node); child != 0; child = OF_peer(child)) {
		char name[32];
		memset(name, 0, sizeof(name));
		OF_getprop(child, "name", name, sizeof(name));

		if (strncmp(name, "sensors", 8) == 0)
			smu_attach_sensors(dev, child);

		if (strncmp(name, "smu-i2c-control", 15) == 0)
			smu_attach_i2c(dev, child);
	}

	/* Some SMUs have the I2C children directly under the bus. */
	smu_attach_i2c(dev, node);

	/*
	 * Collect calibration constants.
	 */
	smu_get_datablock(dev, SMU_CPUTEMP_CAL, data, sizeof(data));
	sc->sc_cpu_diode_scale = (data[4] << 8) + data[5];
	sc->sc_cpu_diode_offset = (data[6] << 8) + data[7];

	smu_get_datablock(dev, SMU_CPUVOLT_CAL, data, sizeof(data));
	sc->sc_cpu_volt_scale = (data[4] << 8) + data[5];
	sc->sc_cpu_volt_offset = (data[6] << 8) + data[7];
	sc->sc_cpu_curr_scale = (data[8] << 8) + data[9];
	sc->sc_cpu_curr_offset = (data[10] << 8) + data[11];

	smu_get_datablock(dev, SMU_SLOTPW_CAL, data, sizeof(data));
	sc->sc_slots_pow_scale = (data[4] << 8) + data[5];
	sc->sc_slots_pow_offset = (data[6] << 8) + data[7];

	/*
	 * Set up LED interface
	 */
	sc->sc_leddev = led_create(smu_set_sleepled, dev, "sleepled");

	/*
	 * Reset on power loss behavior
	 */

	SYSCTL_ADD_PROC(device_get_sysctl_ctx(dev),
            SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO,
	    "server_mode", CTLTYPE_INT | CTLFLAG_RW, dev, 0,
	    smu_server_mode, "I", "Enable reboot after power failure");

	/*
	 * Set up doorbell interrupt.
	 */
	sc->sc_doorbellirqid = 0;
	sc->sc_doorbellirq = bus_alloc_resource_any(smu_doorbell, SYS_RES_IRQ,
	    &sc->sc_doorbellirqid, RF_ACTIVE);
	bus_setup_intr(smu_doorbell, sc->sc_doorbellirq,
	    INTR_TYPE_MISC | INTR_MPSAFE, NULL, smu_doorbell_intr, dev,
	    &sc->sc_doorbellirqcookie);
	powerpc_config_intr(rman_get_start(sc->sc_doorbellirq),
	    INTR_TRIGGER_EDGE, INTR_POLARITY_LOW);

	/*
	 * Connect RTC interface.
	 */
	clock_register(dev, 1000);

	/*
	 * Learn about shutdown events
	 */
	EVENTHANDLER_REGISTER(shutdown_final, smu_shutdown, dev,
	    SHUTDOWN_PRI_LAST);

	return (bus_generic_attach(dev));
}

static const struct ofw_bus_devinfo *
smu_get_devinfo(device_t bus, device_t dev)
{

	return (device_get_ivars(dev));
}

static void
smu_send_cmd(device_t dev, struct smu_cmd *cmd)
{
	struct smu_softc *sc;

	sc = device_get_softc(dev);

	mtx_assert(&sc->sc_mtx, MA_OWNED);

	if (sc->sc_u3)
		powerpc_pow_enabled = 0; /* SMU cannot work if we go to NAP */

	sc->sc_cur_cmd = cmd;

	/* Copy the command to the mailbox */
	sc->sc_cmd->cmd = cmd->cmd;
	sc->sc_cmd->len = cmd->len;
	memcpy(sc->sc_cmd->data, cmd->data, sizeof(cmd->data));
	bus_dmamap_sync(sc->sc_dmatag, sc->sc_cmd_dmamap, BUS_DMASYNC_PREWRITE);
	bus_space_write_4(sc->sc_bt, sc->sc_mailbox, 0, sc->sc_cmd_phys);

	/* Flush the cacheline it is in -- SMU bypasses the cache */
	__asm __volatile("sync; dcbf 0,%0; sync" :: "r"(sc->sc_cmd): "memory");

	/* Ring SMU doorbell */
	macgpio_write(smu_doorbell, GPIO_DDR_OUTPUT);
}

static void
smu_doorbell_intr(void *xdev)
{
	device_t smu;
	struct smu_softc *sc;
	int doorbell_ack;

	smu = xdev;
	doorbell_ack = macgpio_read(smu_doorbell);
	sc = device_get_softc(smu);

	if (doorbell_ack != (GPIO_DDR_OUTPUT | GPIO_LEVEL_RO | GPIO_DATA))
		return;

	mtx_lock(&sc->sc_mtx);

	if (sc->sc_cur_cmd == NULL)	/* spurious */
		goto done;

	/* Check result. First invalidate the cache again... */
	__asm __volatile("dcbf 0,%0; sync" :: "r"(sc->sc_cmd) : "memory");

	bus_dmamap_sync(sc->sc_dmatag, sc->sc_cmd_dmamap, BUS_DMASYNC_POSTREAD);

	sc->sc_cur_cmd->cmd = sc->sc_cmd->cmd;
	sc->sc_cur_cmd->len = sc->sc_cmd->len;
	memcpy(sc->sc_cur_cmd->data, sc->sc_cmd->data,
	    sizeof(sc->sc_cmd->data));
	wakeup(sc->sc_cur_cmd);
	sc->sc_cur_cmd = NULL;
	if (sc->sc_u3)
		powerpc_pow_enabled = 1;

    done:
	/* Queue next command if one is pending */
	if (STAILQ_FIRST(&sc->sc_cmdq) != NULL) {
		sc->sc_cur_cmd = STAILQ_FIRST(&sc->sc_cmdq);
		STAILQ_REMOVE_HEAD(&sc->sc_cmdq, cmd_q);
		smu_send_cmd(smu, sc->sc_cur_cmd);
	}

	mtx_unlock(&sc->sc_mtx);
}

static int
smu_run_cmd(device_t dev, struct smu_cmd *cmd, int wait)
{
	struct smu_softc *sc;
	uint8_t cmd_code;
	int error;

	sc = device_get_softc(dev);
	cmd_code = cmd->cmd;

	mtx_lock(&sc->sc_mtx);
	if (sc->sc_cur_cmd != NULL) {
		STAILQ_INSERT_TAIL(&sc->sc_cmdq, cmd, cmd_q);
	} else
		smu_send_cmd(dev, cmd);
	mtx_unlock(&sc->sc_mtx);

	if (!wait)
		return (0);

	if (sc->sc_doorbellirqid < 0) {
		/* Poll if the IRQ has not been set up yet */
		do {
			DELAY(50);
			smu_doorbell_intr(dev);
		} while (sc->sc_cur_cmd != NULL);
	} else {
		/* smu_doorbell_intr will wake us when the command is ACK'ed */
		error = tsleep(cmd, 0, "smu", 800 * hz / 1000);
		if (error != 0)
			smu_doorbell_intr(dev);	/* One last chance */

		if (error != 0) {
		    mtx_lock(&sc->sc_mtx);
		    if (cmd->cmd == cmd_code) {	/* Never processed */
			/* Abort this command if we timed out */
			if (sc->sc_cur_cmd == cmd)
				sc->sc_cur_cmd = NULL;
			else
				STAILQ_REMOVE(&sc->sc_cmdq, cmd, smu_cmd,
				    cmd_q);
			mtx_unlock(&sc->sc_mtx);
			return (error);
		    }
		    error = 0;
		    mtx_unlock(&sc->sc_mtx);
		}
	}

	/* SMU acks the command by inverting the command bits */
	if (cmd->cmd == ((~cmd_code) & 0xff))
		error = 0;
	else
		error = EIO;

	return (error);
}

static int
smu_get_datablock(device_t dev, int8_t id, uint8_t *buf, size_t len)
{
	struct smu_cmd cmd;
	uint8_t addr[4];

	cmd.cmd = SMU_PARTITION;
	cmd.len = 2;
	cmd.data[0] = SMU_PARTITION_LATEST;
	cmd.data[1] = id;

	smu_run_cmd(dev, &cmd, 1);

	addr[0] = addr[1] = 0;
	addr[2] = cmd.data[0];
	addr[3] = cmd.data[1];

	cmd.cmd = SMU_MISC;
	cmd.len = 7;
	cmd.data[0] = SMU_MISC_GET_DATA;
	cmd.data[1] = sizeof(addr);
	memcpy(&cmd.data[2], addr, sizeof(addr));
	cmd.data[6] = len;

	smu_run_cmd(dev, &cmd, 1);
	memcpy(buf, cmd.data, len);
	return (0);
}

static void
smu_slew_cpu_voltage(device_t dev, int to)
{
	struct smu_cmd cmd;

	cmd.cmd = SMU_POWER;
	cmd.len = 8;
	cmd.data[0] = 'V';
	cmd.data[1] = 'S';
	cmd.data[2] = 'L';
	cmd.data[3] = 'E';
	cmd.data[4] = 'W';
	cmd.data[5] = 0xff;
	cmd.data[6] = 1;
	cmd.data[7] = to;

	smu_run_cmd(dev, &cmd, 1);
}

static void
smu_cpufreq_pre_change(device_t dev, const struct cf_level *level)
{
	/*
	 * Make sure the CPU voltage is raised before we raise
	 * the clock.
	 */

	if (level->rel_set[0].freq == 10000 /* max */)
		smu_slew_cpu_voltage(dev, 0);
}

static void
smu_cpufreq_post_change(device_t dev, const struct cf_level *level)
{
	/* We are safe to reduce CPU voltage after a downward transition */

	if (level->rel_set[0].freq < 10000 /* max */)
		smu_slew_cpu_voltage(dev, 1); /* XXX: 1/4 voltage for 970MP? */
}

/* Routines for probing the SMU doorbell GPIO */
static int doorbell_probe(device_t dev);
static int doorbell_attach(device_t dev);

static device_method_t  doorbell_methods[] = {
	/* Device interface */
	DEVMETHOD(device_probe,		doorbell_probe),
	DEVMETHOD(device_attach,	doorbell_attach),
	{ 0, 0 },
};

static driver_t doorbell_driver = {
	"smudoorbell",
	doorbell_methods,
	0
};

static devclass_t doorbell_devclass;

DRIVER_MODULE(smudoorbell, macgpio, doorbell_driver, doorbell_devclass, 0, 0);

static int
doorbell_probe(device_t dev)
{
	const char *name = ofw_bus_get_name(dev);

	if (strcmp(name, "smu-doorbell") != 0)
		return (ENXIO);

	device_set_desc(dev, "SMU Doorbell GPIO");
	device_quiet(dev);
	return (0);
}

static int
doorbell_attach(device_t dev)
{
	smu_doorbell = dev;
	return (0);
}

/*
 * Sensor and fan management
 */

static int
smu_fan_set_rpm(struct smu_fan *fan, int rpm)
{
	device_t smu = fan->dev;
	struct smu_cmd cmd;
	int error;

	cmd.cmd = SMU_FAN;
	error = EIO;

	/* Clamp to allowed range */
	rpm = max(fan->fan.min_rpm, rpm);
	rpm = min(fan->fan.max_rpm, rpm);

	/*
	 * Apple has two fan control mechanisms. We can't distinguish
	 * them except by seeing if the new one fails. If the new one
	 * fails, use the old one.
	 */

	if (!fan->old_style) {
		cmd.len = 4;
		cmd.data[0] = 0x30;
		cmd.data[1] = fan->reg;
		cmd.data[2] = (rpm >> 8) & 0xff;
		cmd.data[3] = rpm & 0xff;

		error = smu_run_cmd(smu, &cmd, 1);
		if (error && error != EWOULDBLOCK)
			fan->old_style = 1;
	}

	if (fan->old_style) {
		cmd.len = 14;
		cmd.data[0] = 0x00; /* RPM fan. */
		cmd.data[1] = 1 << fan->reg;
		cmd.data[2 + 2*fan->reg] = (rpm >> 8) & 0xff;
		cmd.data[3 + 2*fan->reg] = rpm & 0xff;
		error = smu_run_cmd(smu, &cmd, 1);
	}

	if (error == 0)
		fan->setpoint = rpm;

	return (error);
}

static int
smu_fan_read_rpm(struct smu_fan *fan)
{
	device_t smu = fan->dev;
	struct smu_cmd cmd;
	int rpm, error;

	if (!fan->old_style) {
		cmd.cmd = SMU_FAN;
		cmd.len = 2;
		cmd.data[0] = 0x31;
		cmd.data[1] = fan->reg;

		error = smu_run_cmd(smu, &cmd, 1);
		if (error && error != EWOULDBLOCK)
			fan->old_style = 1;

		rpm = (cmd.data[0] << 8) | cmd.data[1];
	}

	if (fan->old_style) {
		cmd.cmd = SMU_FAN;
		cmd.len = 1;
		cmd.data[0] = SMU_RPM_STATUS;

		error = smu_run_cmd(smu, &cmd, 1);
		if (error)
			return (error);

		rpm = (cmd.data[fan->reg*2+1] << 8) | cmd.data[fan->reg*2+2];
	}

	return (rpm);
}
static int
smu_fan_set_pwm(struct smu_fan *fan, int pwm)
{
	device_t smu = fan->dev;
	struct smu_cmd cmd;
	int error;

	cmd.cmd = SMU_FAN;
	error = EIO;

	/* Clamp to allowed range */
	pwm = max(fan->fan.min_rpm, pwm);
	pwm = min(fan->fan.max_rpm, pwm);

	/*
	 * Apple has two fan control mechanisms. We can't distinguish
	 * them except by seeing if the new one fails. If the new one
	 * fails, use the old one.
	 */

	if (!fan->old_style) {
		cmd.len = 4;
		cmd.data[0] = 0x30;
		cmd.data[1] = fan->reg;
		cmd.data[2] = (pwm >> 8) & 0xff;
		cmd.data[3] = pwm & 0xff;

		error = smu_run_cmd(smu, &cmd, 1);
		if (error && error != EWOULDBLOCK)
			fan->old_style = 1;
	}

	if (fan->old_style) {
		cmd.len = 14;
		cmd.data[0] = 0x10; /* PWM fan. */
		cmd.data[1] = 1 << fan->reg;
		cmd.data[2 + 2*fan->reg] = (pwm >> 8) & 0xff;
		cmd.data[3 + 2*fan->reg] = pwm & 0xff;
		error = smu_run_cmd(smu, &cmd, 1);
	}

	if (error == 0)
		fan->setpoint = pwm;

	return (error);
}

static int
smu_fan_read_pwm(struct smu_fan *fan, int *pwm, int *rpm)
{
	device_t smu = fan->dev;
	struct smu_cmd cmd;
	int error;

	if (!fan->old_style) {
		cmd.cmd = SMU_FAN;
		cmd.len = 2;
		cmd.data[0] = 0x31;
		cmd.data[1] = fan->reg;

		error = smu_run_cmd(smu, &cmd, 1);
		if (error && error != EWOULDBLOCK)
			fan->old_style = 1;

		*rpm = (cmd.data[0] << 8) | cmd.data[1];
	}

	if (fan->old_style) {
		cmd.cmd = SMU_FAN;
		cmd.len = 1;
		cmd.data[0] = SMU_PWM_STATUS;

		error = smu_run_cmd(smu, &cmd, 1);
		if (error)
			return (error);

		*rpm = (cmd.data[fan->reg*2+1] << 8) | cmd.data[fan->reg*2+2];
	}
	if (fan->old_style) {
		cmd.cmd = SMU_FAN;
		cmd.len = 14;
		cmd.data[0] = SMU_PWM_SETPOINT;
		cmd.data[1] = 1 << fan->reg;

		error = smu_run_cmd(smu, &cmd, 1);
		if (error)
			return (error);

		*pwm = cmd.data[fan->reg*2+2];
	}
	return (0);
}

static int
smu_fanrpm_sysctl(SYSCTL_HANDLER_ARGS)
{
	device_t smu;
	struct smu_softc *sc;
	struct smu_fan *fan;
	int pwm = 0, rpm, error = 0;

	smu = arg1;
	sc = device_get_softc(smu);
	fan = &sc->sc_fans[arg2 & 0xff];

	if (fan->type == SMU_FAN_RPM) {
		rpm = smu_fan_read_rpm(fan);
		if (rpm < 0)
			return (rpm);

		error = sysctl_handle_int(oidp, &rpm, 0, req);
	} else {
		error = smu_fan_read_pwm(fan, &pwm, &rpm);
		if (error < 0)
			return (EIO);

		switch (arg2 & 0xff00) {
		case SMU_PWM_SYSCTL_PWM:
			error = sysctl_handle_int(oidp, &pwm, 0, req);
			break;
		case SMU_PWM_SYSCTL_RPM:
			error = sysctl_handle_int(oidp, &rpm, 0, req);
			break;
		default:
			/* This should never happen */
			return (EINVAL);
		};
	}
	/* We can only read the RPM from a PWM controlled fan, so return. */
	if ((arg2 & 0xff00) == SMU_PWM_SYSCTL_RPM)
		return (0);

	if (error || !req->newptr)
		return (error);

	sc->sc_lastuserchange = time_uptime;

	if (fan->type == SMU_FAN_RPM)
		return (smu_fan_set_rpm(fan, rpm));
	else
		return (smu_fan_set_pwm(fan, pwm));
}

static void
smu_fill_fan_prop(device_t dev, phandle_t child, int id)
{
	struct smu_fan *fan;
	struct smu_softc *sc;
	char type[32];

	sc = device_get_softc(dev);
	fan = &sc->sc_fans[id];

	OF_getprop(child, "device_type", type, sizeof(type));
	/* We have either RPM or PWM controlled fans. */
	if (strcmp(type, "fan-rpm-control") == 0)
		fan->type = SMU_FAN_RPM;
	else
		fan->type = SMU_FAN_PWM;

	fan->dev = dev;
	fan->old_style = 0;
	OF_getprop(child, "reg", &fan->reg,
		   sizeof(cell_t));
	OF_getprop(child, "min-value", &fan->fan.min_rpm,
		   sizeof(int));
	OF_getprop(child, "max-value", &fan->fan.max_rpm,
		   sizeof(int));
	OF_getprop(child, "zone", &fan->fan.zone,
		   sizeof(int));

	if (OF_getprop(child, "unmanaged-value",
		       &fan->fan.default_rpm,
		       sizeof(int)) != sizeof(int))
		fan->fan.default_rpm = fan->fan.max_rpm;

	OF_getprop(child, "location", fan->fan.name,
		   sizeof(fan->fan.name));

	if (fan->type == SMU_FAN_RPM)
		fan->setpoint = smu_fan_read_rpm(fan);
	else
		smu_fan_read_pwm(fan, &fan->setpoint, &fan->rpm);
}

/* On the first call count the number of fans. In the second call,
 * after allocating the fan struct, fill the properties of the fans.
 */
static int
smu_count_fans(device_t dev)
{
	struct smu_softc *sc;
	phandle_t child, node, root;
	int nfans = 0;

	node = ofw_bus_get_node(dev);
	sc = device_get_softc(dev);

	/* First find the fanroots and count the number of fans. */
	for (root = OF_child(node); root != 0; root = OF_peer(root)) {
		char name[32];
		memset(name, 0, sizeof(name));
		OF_getprop(root, "name", name, sizeof(name));
		if (strncmp(name, "rpm-fans", 9) == 0 ||
		    strncmp(name, "pwm-fans", 9) == 0 ||
		    strncmp(name, "fans", 5) == 0)
			for (child = OF_child(root); child != 0;
			     child = OF_peer(child)) {
				nfans++;
				/* When allocated, fill the fan properties. */
				if (sc->sc_fans != NULL)
					smu_fill_fan_prop(dev, child,
							  nfans - 1);
			}
	}
	if (nfans == 0) {
		device_printf(dev, "WARNING: No fans detected!\n");
		return (0);
	}
	return (nfans);
}

static void
smu_attach_fans(device_t dev, phandle_t fanroot)
{
	struct smu_fan *fan;
	struct smu_softc *sc;
	struct sysctl_oid *oid, *fanroot_oid;
	struct sysctl_ctx_list *ctx;
	char sysctl_name[32];
	int i, j;

	sc = device_get_softc(dev);

	/* Get the number of fans. */
	sc->sc_nfans = smu_count_fans(dev);
	if (sc->sc_nfans == 0)
		return;

	/* Now we're able to allocate memory for the fans struct. */
	sc->sc_fans = malloc(sc->sc_nfans * sizeof(struct smu_fan), M_SMU,
	    M_WAITOK | M_ZERO);

	/* Now fill in the properties. */
	smu_count_fans(dev);

	/* Register fans with pmac_thermal */
	for (i = 0; i < sc->sc_nfans; i++)
		pmac_thermal_fan_register(&sc->sc_fans[i].fan);

	ctx = device_get_sysctl_ctx(dev);
	fanroot_oid = SYSCTL_ADD_NODE(ctx,
	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO, "fans",
	    CTLFLAG_RD, 0, "SMU Fan Information");

	/* Add sysctls */
	for (i = 0; i < sc->sc_nfans; i++) {
		fan = &sc->sc_fans[i];
		for (j = 0; j < strlen(fan->fan.name); j++) {
			sysctl_name[j] = tolower(fan->fan.name[j]);
			if (isspace(sysctl_name[j]))
				sysctl_name[j] = '_';
		}
		sysctl_name[j] = 0;
		if (fan->type == SMU_FAN_RPM) {
			oid = SYSCTL_ADD_NODE(ctx,
					      SYSCTL_CHILDREN(fanroot_oid),
					      OID_AUTO, sysctl_name,
					      CTLFLAG_RD, 0, "Fan Information");
			SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(oid), OID_AUTO,
				       "minrpm", CTLTYPE_INT | CTLFLAG_RD,
				       &fan->fan.min_rpm, sizeof(int),
				       "Minimum allowed RPM");
			SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(oid), OID_AUTO,
				       "maxrpm", CTLTYPE_INT | CTLFLAG_RD,
				       &fan->fan.max_rpm, sizeof(int),
				       "Maximum allowed RPM");
			SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(oid), OID_AUTO,
					"rpm",CTLTYPE_INT | CTLFLAG_RW |
					CTLFLAG_MPSAFE, dev, i,
					smu_fanrpm_sysctl, "I", "Fan RPM");

			fan->fan.read = (int (*)(struct pmac_fan *))smu_fan_read_rpm;
			fan->fan.set = (int (*)(struct pmac_fan *, int))smu_fan_set_rpm;

		} else {
			oid = SYSCTL_ADD_NODE(ctx,
					      SYSCTL_CHILDREN(fanroot_oid),
					      OID_AUTO, sysctl_name,
					      CTLFLAG_RD, 0, "Fan Information");
			SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(oid), OID_AUTO,
				       "minpwm", CTLTYPE_INT | CTLFLAG_RD,
				       &fan->fan.min_rpm, sizeof(int),
				       "Minimum allowed PWM in %");
			SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(oid), OID_AUTO,
				       "maxpwm", CTLTYPE_INT | CTLFLAG_RD,
				       &fan->fan.max_rpm, sizeof(int),
				       "Maximum allowed PWM in %");
			SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(oid), OID_AUTO,
					"pwm",CTLTYPE_INT | CTLFLAG_RW |
					CTLFLAG_MPSAFE, dev,
					SMU_PWM_SYSCTL_PWM | i,
					smu_fanrpm_sysctl, "I", "Fan PWM in %");
			SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(oid), OID_AUTO,
					"rpm",CTLTYPE_INT | CTLFLAG_RD |
					CTLFLAG_MPSAFE, dev,
					SMU_PWM_SYSCTL_RPM | i,
					smu_fanrpm_sysctl, "I", "Fan RPM");
			fan->fan.read = NULL;
			fan->fan.set = (int (*)(struct pmac_fan *, int))smu_fan_set_pwm;

		}
		if (bootverbose)
			device_printf(dev, "Fan: %s type: %d\n",
				      fan->fan.name, fan->type);
	}
}

static int
smu_sensor_read(struct smu_sensor *sens)
{
	device_t smu = sens->dev;
	struct smu_cmd cmd;
	struct smu_softc *sc;
	int64_t value;
	int error;

	cmd.cmd = SMU_ADC;
	cmd.len = 1;
	cmd.data[0] = sens->reg;
	error = 0;

	error = smu_run_cmd(smu, &cmd, 1);
	if (error != 0)
		return (-1);

	sc = device_get_softc(smu);
	value = (cmd.data[0] << 8) | cmd.data[1];

	switch (sens->type) {
	case SMU_TEMP_SENSOR:
		value *= sc->sc_cpu_diode_scale;
		value >>= 3;
		value += ((int64_t)sc->sc_cpu_diode_offset) << 9;
		value <<= 1;

		/* Convert from 16.16 fixed point degC into integer 0.1 K. */
		value = 10*(value >> 16) + ((10*(value & 0xffff)) >> 16) + 2732;
		break;
	case SMU_VOLTAGE_SENSOR:
		value *= sc->sc_cpu_volt_scale;
		value += sc->sc_cpu_volt_offset;
		value <<= 4;

		/* Convert from 16.16 fixed point V into mV. */
		value *= 15625;
		value /= 1024;
		value /= 1000;
		break;
	case SMU_CURRENT_SENSOR:
		value *= sc->sc_cpu_curr_scale;
		value += sc->sc_cpu_curr_offset;
		value <<= 4;

		/* Convert from 16.16 fixed point A into mA. */
		value *= 15625;
		value /= 1024;
		value /= 1000;
		break;
	case SMU_POWER_SENSOR:
		value *= sc->sc_slots_pow_scale;
		value += sc->sc_slots_pow_offset;
		value <<= 4;

		/* Convert from 16.16 fixed point W into mW. */
		value *= 15625;
		value /= 1024;
		value /= 1000;
		break;
	}

	return (value);
}

static int
smu_sensor_sysctl(SYSCTL_HANDLER_ARGS)
{
	device_t smu;
	struct smu_softc *sc;
	struct smu_sensor *sens;
	int value, error;

	smu = arg1;
	sc = device_get_softc(smu);
	sens = &sc->sc_sensors[arg2];

	value = smu_sensor_read(sens);
	if (value < 0)
		return (EBUSY);

	error = sysctl_handle_int(oidp, &value, 0, req);

	return (error);
}

static void
smu_attach_sensors(device_t dev, phandle_t sensroot)
{
	struct smu_sensor *sens;
	struct smu_softc *sc;
	struct sysctl_oid *sensroot_oid;
	struct sysctl_ctx_list *ctx;
	phandle_t child;
	char type[32];
	int i;

	sc = device_get_softc(dev);
	sc->sc_nsensors = 0;

	for (child = OF_child(sensroot); child != 0; child = OF_peer(child))
		sc->sc_nsensors++;

	if (sc->sc_nsensors == 0) {
		device_printf(dev, "WARNING: No sensors detected!\n");
		return;
	}

	sc->sc_sensors = malloc(sc->sc_nsensors * sizeof(struct smu_sensor),
	    M_SMU, M_WAITOK | M_ZERO);

	sens = sc->sc_sensors;
	sc->sc_nsensors = 0;

	ctx = device_get_sysctl_ctx(dev);
	sensroot_oid = SYSCTL_ADD_NODE(ctx,
	    SYSCTL_CHILDREN(device_get_sysctl_tree(dev)), OID_AUTO, "sensors",
	    CTLFLAG_RD, 0, "SMU Sensor Information");

	for (child = OF_child(sensroot); child != 0; child = OF_peer(child)) {
		char sysctl_name[40], sysctl_desc[40];
		const char *units;

		sens->dev = dev;
		OF_getprop(child, "device_type", type, sizeof(type));

		if (strcmp(type, "current-sensor") == 0) {
			sens->type = SMU_CURRENT_SENSOR;
			units = "mA";
		} else if (strcmp(type, "temp-sensor") == 0) {
			sens->type = SMU_TEMP_SENSOR;
			units = "C";
		} else if (strcmp(type, "voltage-sensor") == 0) {
			sens->type = SMU_VOLTAGE_SENSOR;
			units = "mV";
		} else if (strcmp(type, "power-sensor") == 0) {
			sens->type = SMU_POWER_SENSOR;
			units = "mW";
		} else {
			continue;
		}

		OF_getprop(child, "reg", &sens->reg, sizeof(cell_t));
		OF_getprop(child, "zone", &sens->therm.zone, sizeof(int));
		OF_getprop(child, "location", sens->therm.name,
		    sizeof(sens->therm.name));

		for (i = 0; i < strlen(sens->therm.name); i++) {
			sysctl_name[i] = tolower(sens->therm.name[i]);
			if (isspace(sysctl_name[i]))
				sysctl_name[i] = '_';
		}
		sysctl_name[i] = 0;

		sprintf(sysctl_desc,"%s (%s)", sens->therm.name, units);

		SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(sensroot_oid), OID_AUTO,
		    sysctl_name, CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
		    dev, sc->sc_nsensors, smu_sensor_sysctl,
		    (sens->type == SMU_TEMP_SENSOR) ? "IK" : "I", sysctl_desc);

		if (sens->type == SMU_TEMP_SENSOR) {
			/* Make up some numbers */
			sens->therm.target_temp = 500 + 2732; /* 50 C */
			sens->therm.max_temp = 900 + 2732; /* 90 C */

			sens->therm.read =
			    (int (*)(struct pmac_therm *))smu_sensor_read;
			pmac_thermal_sensor_register(&sens->therm);
		}

		sens++;
		sc->sc_nsensors++;
	}
}

static void
smu_set_sleepled(void *xdev, int onoff)
{
	static struct smu_cmd cmd;
	device_t smu = xdev;

	cmd.cmd = SMU_MISC;
	cmd.len = 3;
	cmd.data[0] = SMU_MISC_LED_CTRL;
	cmd.data[1] = 0;
	cmd.data[2] = onoff;

	smu_run_cmd(smu, &cmd, 0);
}

static int
smu_server_mode(SYSCTL_HANDLER_ARGS)
{
	struct smu_cmd cmd;
	u_int server_mode;
	device_t smu = arg1;
	int error;

	cmd.cmd = SMU_POWER_EVENTS;
	cmd.len = 1;
	cmd.data[0] = SMU_PWR_GET_POWERUP;

	error = smu_run_cmd(smu, &cmd, 1);

	if (error)
		return (error);

	server_mode = (cmd.data[1] & SMU_WAKEUP_AC_INSERT) ? 1 : 0;

	error = sysctl_handle_int(oidp, &server_mode, 0, req);

	if (error || !req->newptr)
		return (error);

	if (server_mode == 1)
		cmd.data[0] = SMU_PWR_SET_POWERUP;
	else if (server_mode == 0)
		cmd.data[0] = SMU_PWR_CLR_POWERUP;
	else
		return (EINVAL);

	cmd.len = 3;
	cmd.data[1] = 0;
	cmd.data[2] = SMU_WAKEUP_AC_INSERT;

	return (smu_run_cmd(smu, &cmd, 1));
}

static void
smu_shutdown(void *xdev, int howto)
{
	device_t smu = xdev;
	struct smu_cmd cmd;

	cmd.cmd = SMU_POWER;
	if (howto & RB_HALT)
		strcpy(cmd.data, "SHUTDOWN");
	else
		strcpy(cmd.data, "RESTART");

	cmd.len = strlen(cmd.data);

	smu_run_cmd(smu, &cmd, 1);

	for (;;);
}

static int
smu_gettime(device_t dev, struct timespec *ts)
{
	struct smu_cmd cmd;
	struct clocktime ct;

	cmd.cmd = SMU_RTC;
	cmd.len = 1;
	cmd.data[0] = SMU_RTC_GET;

	if (smu_run_cmd(dev, &cmd, 1) != 0)
		return (ENXIO);

	ct.nsec	= 0;
	ct.sec	= bcd2bin(cmd.data[0]);
	ct.min	= bcd2bin(cmd.data[1]);
	ct.hour	= bcd2bin(cmd.data[2]);
	ct.dow	= bcd2bin(cmd.data[3]);
	ct.day	= bcd2bin(cmd.data[4]);
	ct.mon	= bcd2bin(cmd.data[5]);
	ct.year	= bcd2bin(cmd.data[6]) + 2000;

	return (clock_ct_to_ts(&ct, ts));
}

static int
smu_settime(device_t dev, struct timespec *ts)
{
	static struct smu_cmd cmd;
	struct clocktime ct;

	cmd.cmd = SMU_RTC;
	cmd.len = 8;
	cmd.data[0] = SMU_RTC_SET;

	clock_ts_to_ct(ts, &ct);

	cmd.data[1] = bin2bcd(ct.sec);
	cmd.data[2] = bin2bcd(ct.min);
	cmd.data[3] = bin2bcd(ct.hour);
	cmd.data[4] = bin2bcd(ct.dow);
	cmd.data[5] = bin2bcd(ct.day);
	cmd.data[6] = bin2bcd(ct.mon);
	cmd.data[7] = bin2bcd(ct.year - 2000);

	return (smu_run_cmd(dev, &cmd, 0));
}

/* SMU I2C Interface */

static int smuiic_probe(device_t dev);
static int smuiic_attach(device_t dev);
static int smuiic_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs);
static phandle_t smuiic_get_node(device_t bus, device_t dev);

static device_method_t smuiic_methods[] = {
	/* device interface */
	DEVMETHOD(device_probe,         smuiic_probe),
	DEVMETHOD(device_attach,        smuiic_attach),

	/* iicbus interface */
	DEVMETHOD(iicbus_callback,      iicbus_null_callback),
	DEVMETHOD(iicbus_transfer,      smuiic_transfer),

	/* ofw_bus interface */
	DEVMETHOD(ofw_bus_get_node,     smuiic_get_node),

	{ 0, 0 }
};

struct smuiic_softc {
	struct mtx	sc_mtx;
	volatile int	sc_iic_inuse;
	int		sc_busno;
};

static driver_t smuiic_driver = {
	"iichb",
	smuiic_methods,
	sizeof(struct smuiic_softc)
};
static devclass_t smuiic_devclass;

DRIVER_MODULE(smuiic, smu, smuiic_driver, smuiic_devclass, 0, 0);

static void
smu_attach_i2c(device_t smu, phandle_t i2croot)
{
	phandle_t child;
	device_t cdev;
	struct ofw_bus_devinfo *dinfo;
	char name[32];

	for (child = OF_child(i2croot); child != 0; child = OF_peer(child)) {
		if (OF_getprop(child, "name", name, sizeof(name)) <= 0)
			continue;

		if (strcmp(name, "i2c-bus") != 0 && strcmp(name, "i2c") != 0)
			continue;

		dinfo = malloc(sizeof(struct ofw_bus_devinfo), M_SMU,
		    M_WAITOK | M_ZERO);
		if (ofw_bus_gen_setup_devinfo(dinfo, child) != 0) {
			free(dinfo, M_SMU);
			continue;
		}

		cdev = device_add_child(smu, NULL, -1);
		if (cdev == NULL) {
			device_printf(smu, "<%s>: device_add_child failed\n",
			    dinfo->obd_name);
			ofw_bus_gen_destroy_devinfo(dinfo);
			free(dinfo, M_SMU);
			continue;
		}
		device_set_ivars(cdev, dinfo);
	}
}

static int
smuiic_probe(device_t dev)
{
	const char *name;

	name = ofw_bus_get_name(dev);
	if (name == NULL)
		return (ENXIO);

	if (strcmp(name, "i2c-bus") == 0 || strcmp(name, "i2c") == 0) {
		device_set_desc(dev, "SMU I2C controller");
		return (0);
	}

	return (ENXIO);
}

static int
smuiic_attach(device_t dev)
{
	struct smuiic_softc *sc = device_get_softc(dev);
	mtx_init(&sc->sc_mtx, "smuiic", NULL, MTX_DEF);
	sc->sc_iic_inuse = 0;

	/* Get our bus number */
	OF_getprop(ofw_bus_get_node(dev), "reg", &sc->sc_busno,
	    sizeof(sc->sc_busno));

	/* Add the IIC bus layer */
	device_add_child(dev, "iicbus", -1);

	return (bus_generic_attach(dev));
}

static int
smuiic_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
{
	struct smuiic_softc *sc = device_get_softc(dev);
	struct smu_cmd cmd;
	int i, j, error;

	mtx_lock(&sc->sc_mtx);
	while (sc->sc_iic_inuse)
		mtx_sleep(sc, &sc->sc_mtx, 0, "smuiic", 100);

	sc->sc_iic_inuse = 1;
	error = 0;

	for (i = 0; i < nmsgs; i++) {
		cmd.cmd = SMU_I2C;
		cmd.data[0] = sc->sc_busno;
		if (msgs[i].flags & IIC_M_NOSTOP)
			cmd.data[1] = SMU_I2C_COMBINED;
		else
			cmd.data[1] = SMU_I2C_SIMPLE;

		cmd.data[2] = msgs[i].slave;
		if (msgs[i].flags & IIC_M_RD)
			cmd.data[2] |= 1;

		if (msgs[i].flags & IIC_M_NOSTOP) {
			KASSERT(msgs[i].len < 4,
			    ("oversize I2C combined message"));

			cmd.data[3] = min(msgs[i].len, 3);
			memcpy(&cmd.data[4], msgs[i].buf, min(msgs[i].len, 3));
			i++; /* Advance to next part of message */
		} else {
			cmd.data[3] = 0;
			memset(&cmd.data[4], 0, 3);
		}

		cmd.data[7] = msgs[i].slave;
		if (msgs[i].flags & IIC_M_RD)
			cmd.data[7] |= 1;

		cmd.data[8] = msgs[i].len;
		if (msgs[i].flags & IIC_M_RD) {
			memset(&cmd.data[9], 0xff, msgs[i].len);
			cmd.len = 9;
		} else {
			memcpy(&cmd.data[9], msgs[i].buf, msgs[i].len);
			cmd.len = 9 + msgs[i].len;
		}

		mtx_unlock(&sc->sc_mtx);
		smu_run_cmd(device_get_parent(dev), &cmd, 1);
		mtx_lock(&sc->sc_mtx);

		for (j = 0; j < 10; j++) {
			cmd.cmd = SMU_I2C;
			cmd.len = 1;
			cmd.data[0] = 0;
			memset(&cmd.data[1], 0xff, msgs[i].len);

			mtx_unlock(&sc->sc_mtx);
			smu_run_cmd(device_get_parent(dev), &cmd, 1);
			mtx_lock(&sc->sc_mtx);

			if (!(cmd.data[0] & 0x80))
				break;

			mtx_sleep(sc, &sc->sc_mtx, 0, "smuiic", 10);
		}

		if (cmd.data[0] & 0x80) {
			error = EIO;
			msgs[i].len = 0;
			goto exit;
		}
		memcpy(msgs[i].buf, &cmd.data[1], msgs[i].len);
		msgs[i].len = cmd.len - 1;
	}

    exit:
	sc->sc_iic_inuse = 0;
	mtx_unlock(&sc->sc_mtx);
	wakeup(sc);
	return (error);
}

static phandle_t
smuiic_get_node(device_t bus, device_t dev)
{

	return (ofw_bus_get_node(bus));
}