Switch the bcm2835 cpufreq driver to use the firmware interface

Use the new Raspberry Pi firmware driver in the cpufreq driver. It is
intended all drivers that need to interact with the firmware will move to
use the firmware driver, this is the first.

Reviewed by:	manu
Sponsored by:	Innovate UK
Differential Revision:	https://reviews.freebsd.org/D25609

1 files changed, 156 insertions, 203 deletions

diff --git a/sys/arm/broadcom/bcm2835/bcm2835_cpufreq.c b/sys/arm/broadcom/bcm2835/bcm2835_cpufreq.c
index 1b5e3a63e09e..15c1106cf36f 100644
--- a/sys/arm/broadcom/bcm2835/bcm2835_cpufreq.c
+++ b/sys/arm/broadcom/bcm2835/bcm2835_cpufreq.c
@@ -47,12 +47,10 @@ __FBSDID("$FreeBSD$");
 #include <dev/ofw/ofw_bus.h>
 #include <dev/ofw/ofw_bus_subr.h>
 
-#include <arm/broadcom/bcm2835/bcm2835_mbox.h>
-#include <arm/broadcom/bcm2835/bcm2835_mbox_prop.h>
+#include <arm/broadcom/bcm2835/bcm2835_firmware.h>
 #include <arm/broadcom/bcm2835/bcm2835_vcbus.h>
 
 #include "cpufreq_if.h"
-#include "mbox_if.h"
 
 #ifdef DEBUG
 #define DPRINTF(fmt, ...) do {			\
@@ -101,6 +99,7 @@ static struct sysctl_ctx_list bcm2835_sysctl_ctx;
 
 struct bcm2835_cpufreq_softc {
 	device_t	dev;
+	device_t	firmware;
 	int		arm_max_freq;
 	int		arm_min_freq;
 	int		core_max_freq;
@@ -161,7 +160,7 @@ static int
 bcm2835_cpufreq_get_clock_rate(struct bcm2835_cpufreq_softc *sc,
     uint32_t clock_id)
 {
-	struct msg_get_clock_rate msg;
+	union msg_get_clock_rate_body msg;
 	int rate;
 	int err;
 
@@ -181,16 +180,11 @@ bcm2835_cpufreq_get_clock_rate(struct bcm2835_cpufreq_softc *sc,
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_GET_CLOCK_RATE;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.clock_id = clock_id;
-	msg.end_tag = 0;
+	msg.req.clock_id = clock_id;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_GET_CLOCK_RATE, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't get clock rate (id=%u)\n",
 		    clock_id);
@@ -198,7 +192,7 @@ bcm2835_cpufreq_get_clock_rate(struct bcm2835_cpufreq_softc *sc,
 	}
 
 	/* result (Hz) */
-	rate = (int)msg.body.resp.rate_hz;
+	rate = (int)msg.resp.rate_hz;
 	DPRINTF("clock = %d(Hz)\n", rate);
 	return (rate);
 }
@@ -207,7 +201,7 @@ static int
 bcm2835_cpufreq_get_max_clock_rate(struct bcm2835_cpufreq_softc *sc,
     uint32_t clock_id)
 {
-	struct msg_get_max_clock_rate msg;
+	union msg_get_clock_rate_body msg;
 	int rate;
 	int err;
 
@@ -227,16 +221,11 @@ bcm2835_cpufreq_get_max_clock_rate(struct bcm2835_cpufreq_softc *sc,
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_GET_MAX_CLOCK_RATE;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.clock_id = clock_id;
-	msg.end_tag = 0;
+	msg.req.clock_id = clock_id;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_GET_MAX_CLOCK_RATE, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't get max clock rate (id=%u)\n",
 		    clock_id);
@@ -244,7 +233,7 @@ bcm2835_cpufreq_get_max_clock_rate(struct bcm2835_cpufreq_softc *sc,
 	}
 
 	/* result (Hz) */
-	rate = (int)msg.body.resp.rate_hz;
+	rate = (int)msg.resp.rate_hz;
 	DPRINTF("clock = %d(Hz)\n", rate);
 	return (rate);
 }
@@ -253,7 +242,7 @@ static int
 bcm2835_cpufreq_get_min_clock_rate(struct bcm2835_cpufreq_softc *sc,
     uint32_t clock_id)
 {
-	struct msg_get_min_clock_rate msg;
+	union msg_get_clock_rate_body msg;
 	int rate;
 	int err;
 
@@ -273,16 +262,11 @@ bcm2835_cpufreq_get_min_clock_rate(struct bcm2835_cpufreq_softc *sc,
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_GET_MIN_CLOCK_RATE;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.clock_id = clock_id;
-	msg.end_tag = 0;
+	msg.req.clock_id = clock_id;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_GET_MIN_CLOCK_RATE, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't get min clock rate (id=%u)\n",
 		    clock_id);
@@ -290,7 +274,7 @@ bcm2835_cpufreq_get_min_clock_rate(struct bcm2835_cpufreq_softc *sc,
 	}
 
 	/* result (Hz) */
-	rate = (int)msg.body.resp.rate_hz;
+	rate = (int)msg.resp.rate_hz;
 	DPRINTF("clock = %d(Hz)\n", rate);
 	return (rate);
 }
@@ -299,7 +283,7 @@ static int
 bcm2835_cpufreq_set_clock_rate(struct bcm2835_cpufreq_softc *sc,
     uint32_t clock_id, uint32_t rate_hz)
 {
-	struct msg_set_clock_rate msg;
+	union msg_set_clock_rate_body msg;
 	int rate;
 	int err;
 
@@ -320,17 +304,12 @@ bcm2835_cpufreq_set_clock_rate(struct bcm2835_cpufreq_softc *sc,
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_SET_CLOCK_RATE;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.clock_id = clock_id;
-	msg.body.req.rate_hz = rate_hz;
-	msg.end_tag = 0;
+	msg.req.clock_id = clock_id;
+	msg.req.rate_hz = rate_hz;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_SET_CLOCK_RATE, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't set clock rate (id=%u)\n",
 		    clock_id);
@@ -338,7 +317,7 @@ bcm2835_cpufreq_set_clock_rate(struct bcm2835_cpufreq_softc *sc,
 	}
 
 	/* workaround for core clock */
-	if (clock_id == BCM2835_MBOX_CLOCK_ID_CORE) {
+	if (clock_id == BCM2835_FIRMWARE_CLOCK_ID_CORE) {
 		/* for safety (may change voltage without changing clock) */
 		DELAY(TRANSITION_LATENCY);
 
@@ -349,17 +328,12 @@ bcm2835_cpufreq_set_clock_rate(struct bcm2835_cpufreq_softc *sc,
 
 		/* setup single tag buffer */
 		memset(&msg, 0, sizeof(msg));
-		msg.hdr.buf_size = sizeof(msg);
-		msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-		msg.tag_hdr.tag = BCM2835_MBOX_TAG_SET_CLOCK_RATE;
-		msg.tag_hdr.val_buf_size = sizeof(msg.body);
-		msg.tag_hdr.val_len = sizeof(msg.body.req);
-		msg.body.req.clock_id = clock_id;
-		msg.body.req.rate_hz = rate_hz;
-		msg.end_tag = 0;
+		msg.req.clock_id = clock_id;
+		msg.req.rate_hz = rate_hz;
 
 		/* call mailbox property */
-		err = bcm2835_mbox_property(&msg, sizeof(msg));
+		err = bcm2835_firmware_property(sc->firmware,
+		    BCM2835_FIRMWARE_TAG_SET_CLOCK_RATE, &msg, sizeof(msg));
 		if (err) {
 			device_printf(sc->dev,
 			    "can't set clock rate (id=%u)\n", clock_id);
@@ -368,7 +342,7 @@ bcm2835_cpufreq_set_clock_rate(struct bcm2835_cpufreq_softc *sc,
 	}
 
 	/* result (Hz) */
-	rate = (int)msg.body.resp.rate_hz;
+	rate = (int)msg.resp.rate_hz;
 	DPRINTF("clock = %d(Hz)\n", rate);
 	return (rate);
 }
@@ -376,7 +350,7 @@ bcm2835_cpufreq_set_clock_rate(struct bcm2835_cpufreq_softc *sc,
 static int
 bcm2835_cpufreq_get_turbo(struct bcm2835_cpufreq_softc *sc)
 {
-	struct msg_get_turbo msg;
+	union msg_get_turbo_body msg;
 	int level;
 	int err;
 
@@ -396,23 +370,18 @@ bcm2835_cpufreq_get_turbo(struct bcm2835_cpufreq_softc *sc)
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_GET_TURBO;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.id = 0;
-	msg.end_tag = 0;
+	msg.req.id = 0;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_GET_TURBO, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't get turbo\n");
 		return (MSG_ERROR);
 	}
 
 	/* result 0=non-turbo, 1=turbo */
-	level = (int)msg.body.resp.level;
+	level = (int)msg.resp.level;
 	DPRINTF("level = %d\n", level);
 	return (level);
 }
@@ -420,7 +389,7 @@ bcm2835_cpufreq_get_turbo(struct bcm2835_cpufreq_softc *sc)
 static int
 bcm2835_cpufreq_set_turbo(struct bcm2835_cpufreq_softc *sc, uint32_t level)
 {
-	struct msg_set_turbo msg;
+	union msg_set_turbo_body msg;
 	int value;
 	int err;
 
@@ -440,29 +409,25 @@ bcm2835_cpufreq_set_turbo(struct bcm2835_cpufreq_softc *sc, uint32_t level)
 	 */
 
 	/* replace unknown value to OFF */
-	if (level != BCM2835_MBOX_TURBO_ON && level != BCM2835_MBOX_TURBO_OFF)
-		level = BCM2835_MBOX_TURBO_OFF;
+	if (level != BCM2835_FIRMWARE_TURBO_ON &&
+	    level != BCM2835_FIRMWARE_TURBO_OFF)
+		level = BCM2835_FIRMWARE_TURBO_OFF;
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_SET_TURBO;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.id = 0;
-	msg.body.req.level = level;
-	msg.end_tag = 0;
+	msg.req.id = 0;
+	msg.req.level = level;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_SET_TURBO, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't set turbo\n");
 		return (MSG_ERROR);
 	}
 
 	/* result 0=non-turbo, 1=turbo */
-	value = (int)msg.body.resp.level;
+	value = (int)msg.resp.level;
 	DPRINTF("level = %d\n", value);
 	return (value);
 }
@@ -471,7 +436,7 @@ static int
 bcm2835_cpufreq_get_voltage(struct bcm2835_cpufreq_softc *sc,
     uint32_t voltage_id)
 {
-	struct msg_get_voltage msg;
+	union msg_get_voltage_body msg;
 	int value;
 	int err;
 
@@ -491,23 +456,18 @@ bcm2835_cpufreq_get_voltage(struct bcm2835_cpufreq_softc *sc,
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_GET_VOLTAGE;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.voltage_id = voltage_id;
-	msg.end_tag = 0;
+	msg.req.voltage_id = voltage_id;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_GET_VOLTAGE, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't get voltage\n");
 		return (MSG_ERROR);
 	}
 
 	/* result (offset from 1.2V) */
-	value = (int)msg.body.resp.value;
+	value = (int)msg.resp.value;
 	DPRINTF("value = %d\n", value);
 	return (value);
 }
@@ -516,7 +476,7 @@ static int
 bcm2835_cpufreq_get_max_voltage(struct bcm2835_cpufreq_softc *sc,
     uint32_t voltage_id)
 {
-	struct msg_get_max_voltage msg;
+	union msg_get_voltage_body msg;
 	int value;
 	int err;
 
@@ -536,23 +496,18 @@ bcm2835_cpufreq_get_max_voltage(struct bcm2835_cpufreq_softc *sc,
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_GET_MAX_VOLTAGE;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.voltage_id = voltage_id;
-	msg.end_tag = 0;
+	msg.req.voltage_id = voltage_id;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_GET_MAX_VOLTAGE, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't get max voltage\n");
 		return (MSG_ERROR);
 	}
 
 	/* result (offset from 1.2V) */
-	value = (int)msg.body.resp.value;
+	value = (int)msg.resp.value;
 	DPRINTF("value = %d\n", value);
 	return (value);
 }
@@ -560,7 +515,7 @@ static int
 bcm2835_cpufreq_get_min_voltage(struct bcm2835_cpufreq_softc *sc,
     uint32_t voltage_id)
 {
-	struct msg_get_min_voltage msg;
+	union msg_get_voltage_body msg;
 	int value;
 	int err;
 
@@ -580,23 +535,18 @@ bcm2835_cpufreq_get_min_voltage(struct bcm2835_cpufreq_softc *sc,
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_GET_MIN_VOLTAGE;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.voltage_id = voltage_id;
-	msg.end_tag = 0;
+	msg.req.voltage_id = voltage_id;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_GET_MIN_VOLTAGE, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't get min voltage\n");
 		return (MSG_ERROR);
 	}
 
 	/* result (offset from 1.2V) */
-	value = (int)msg.body.resp.value;
+	value = (int)msg.resp.value;
 	DPRINTF("value = %d\n", value);
 	return (value);
 }
@@ -605,7 +555,7 @@ static int
 bcm2835_cpufreq_set_voltage(struct bcm2835_cpufreq_softc *sc,
     uint32_t voltage_id, int32_t value)
 {
-	struct msg_set_voltage msg;
+	union msg_set_voltage_body msg;
 	int err;
 
 	/*
@@ -636,24 +586,19 @@ bcm2835_cpufreq_set_voltage(struct bcm2835_cpufreq_softc *sc,
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_SET_VOLTAGE;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.voltage_id = voltage_id;
-	msg.body.req.value = (uint32_t)value;
-	msg.end_tag = 0;
+	msg.req.voltage_id = voltage_id;
+	msg.req.value = (uint32_t)value;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_SET_VOLTAGE, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't set voltage\n");
 		return (MSG_ERROR);
 	}
 
 	/* result (offset from 1.2V) */
-	value = (int)msg.body.resp.value;
+	value = (int)msg.resp.value;
 	DPRINTF("value = %d\n", value);
 	return (value);
 }
@@ -661,7 +606,7 @@ bcm2835_cpufreq_set_voltage(struct bcm2835_cpufreq_softc *sc,
 static int
 bcm2835_cpufreq_get_temperature(struct bcm2835_cpufreq_softc *sc)
 {
-	struct msg_get_temperature msg;
+	union msg_get_temperature_body msg;
 	int value;
 	int err;
 
@@ -681,23 +626,18 @@ bcm2835_cpufreq_get_temperature(struct bcm2835_cpufreq_softc *sc)
 
 	/* setup single tag buffer */
 	memset(&msg, 0, sizeof(msg));
-	msg.hdr.buf_size = sizeof(msg);
-	msg.hdr.code = BCM2835_MBOX_CODE_REQ;
-	msg.tag_hdr.tag = BCM2835_MBOX_TAG_GET_TEMPERATURE;
-	msg.tag_hdr.val_buf_size = sizeof(msg.body);
-	msg.tag_hdr.val_len = sizeof(msg.body.req);
-	msg.body.req.temperature_id = 0;
-	msg.end_tag = 0;
+	msg.req.temperature_id = 0;
 
 	/* call mailbox property */
-	err = bcm2835_mbox_property(&msg, sizeof(msg));
+	err = bcm2835_firmware_property(sc->firmware,
+	    BCM2835_FIRMWARE_TAG_GET_TEMPERATURE, &msg, sizeof(msg));
 	if (err) {
 		device_printf(sc->dev, "can't get temperature\n");
 		return (MSG_ERROR);
 	}
 
 	/* result (temperature of degree C) */
-	value = (int)msg.body.resp.value;
+	value = (int)msg.resp.value;
 	DPRINTF("value = %d\n", value);
 	return (value);
 }
@@ -713,7 +653,7 @@ sysctl_bcm2835_cpufreq_arm_freq(SYSCTL_HANDLER_ARGS)
 
 	/* get realtime value */
 	VC_LOCK(sc);
-	val = bcm2835_cpufreq_get_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_ARM);
+	val = bcm2835_cpufreq_get_clock_rate(sc, BCM2835_FIRMWARE_CLOCK_ID_ARM);
 	VC_UNLOCK(sc);
 	if (val == MSG_ERROR)
 		return (EIO);
@@ -724,7 +664,7 @@ sysctl_bcm2835_cpufreq_arm_freq(SYSCTL_HANDLER_ARGS)
 
 	/* write request */
 	VC_LOCK(sc);
-	err = bcm2835_cpufreq_set_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_ARM,
+	err = bcm2835_cpufreq_set_clock_rate(sc, BCM2835_FIRMWARE_CLOCK_ID_ARM,
 	    val);
 	VC_UNLOCK(sc);
 	if (err == MSG_ERROR) {
@@ -745,7 +685,8 @@ sysctl_bcm2835_cpufreq_core_freq(SYSCTL_HANDLER_ARGS)
 
 	/* get realtime value */
 	VC_LOCK(sc);
-	val = bcm2835_cpufreq_get_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_CORE);
+	val = bcm2835_cpufreq_get_clock_rate(sc,
+	    BCM2835_FIRMWARE_CLOCK_ID_CORE);
 	VC_UNLOCK(sc);
 	if (val == MSG_ERROR)
 		return (EIO);
@@ -756,7 +697,7 @@ sysctl_bcm2835_cpufreq_core_freq(SYSCTL_HANDLER_ARGS)
 
 	/* write request */
 	VC_LOCK(sc);
-	err = bcm2835_cpufreq_set_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_CORE,
+	err = bcm2835_cpufreq_set_clock_rate(sc, BCM2835_FIRMWARE_CLOCK_ID_CORE,
 	    val);
 	if (err == MSG_ERROR) {
 		VC_UNLOCK(sc);
@@ -778,7 +719,8 @@ sysctl_bcm2835_cpufreq_sdram_freq(SYSCTL_HANDLER_ARGS)
 
 	/* get realtime value */
 	VC_LOCK(sc);
-	val = bcm2835_cpufreq_get_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_SDRAM);
+	val = bcm2835_cpufreq_get_clock_rate(sc,
+	    BCM2835_FIRMWARE_CLOCK_ID_SDRAM);
 	VC_UNLOCK(sc);
 	if (val == MSG_ERROR)
 		return (EIO);
@@ -789,8 +731,8 @@ sysctl_bcm2835_cpufreq_sdram_freq(SYSCTL_HANDLER_ARGS)
 
 	/* write request */
 	VC_LOCK(sc);
-	err = bcm2835_cpufreq_set_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_SDRAM,
-	    val);
+	err = bcm2835_cpufreq_set_clock_rate(sc,
+	    BCM2835_FIRMWARE_CLOCK_ID_SDRAM, val);
 	VC_UNLOCK(sc);
 	if (err == MSG_ERROR) {
 		device_printf(sc->dev, "set clock sdram_freq error\n");
@@ -821,9 +763,9 @@ sysctl_bcm2835_cpufreq_turbo(SYSCTL_HANDLER_ARGS)
 
 	/* write request */
 	if (val > 0)
-		sc->turbo_mode = BCM2835_MBOX_TURBO_ON;
+		sc->turbo_mode = BCM2835_FIRMWARE_TURBO_ON;
 	else
-		sc->turbo_mode = BCM2835_MBOX_TURBO_OFF;
+		sc->turbo_mode = BCM2835_FIRMWARE_TURBO_OFF;
 
 	VC_LOCK(sc);
 	err = bcm2835_cpufreq_set_turbo(sc, sc->turbo_mode);
@@ -846,7 +788,7 @@ sysctl_bcm2835_cpufreq_voltage_core(SYSCTL_HANDLER_ARGS)
 
 	/* get realtime value */
 	VC_LOCK(sc);
-	val = bcm2835_cpufreq_get_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_CORE);
+	val = bcm2835_cpufreq_get_voltage(sc, BCM2835_FIRMWARE_VOLTAGE_ID_CORE);
 	VC_UNLOCK(sc);
 	if (val == MSG_ERROR)
 		return (EIO);
@@ -861,7 +803,7 @@ sysctl_bcm2835_cpufreq_voltage_core(SYSCTL_HANDLER_ARGS)
 	sc->voltage_core = val;
 
 	VC_LOCK(sc);
-	err = bcm2835_cpufreq_set_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_CORE,
+	err = bcm2835_cpufreq_set_voltage(sc, BCM2835_FIRMWARE_VOLTAGE_ID_CORE,
 	    sc->voltage_core);
 	VC_UNLOCK(sc);
 	if (err == MSG_ERROR) {
@@ -882,7 +824,8 @@ sysctl_bcm2835_cpufreq_voltage_sdram_c(SYSCTL_HANDLER_ARGS)
 
 	/* get realtime value */
 	VC_LOCK(sc);
-	val = bcm2835_cpufreq_get_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_SDRAM_C);
+	val = bcm2835_cpufreq_get_voltage(sc,
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_C);
 	VC_UNLOCK(sc);
 	if (val == MSG_ERROR)
 		return (EIO);
@@ -897,7 +840,8 @@ sysctl_bcm2835_cpufreq_voltage_sdram_c(SYSCTL_HANDLER_ARGS)
 	sc->voltage_sdram_c = val;
 
 	VC_LOCK(sc);
-	err = bcm2835_cpufreq_set_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_SDRAM_C,
+	err = bcm2835_cpufreq_set_voltage(sc,
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_C,
 	   sc->voltage_sdram_c);
 	VC_UNLOCK(sc);
 	if (err == MSG_ERROR) {
@@ -918,7 +862,8 @@ sysctl_bcm2835_cpufreq_voltage_sdram_i(SYSCTL_HANDLER_ARGS)
 
 	/* get realtime value */
 	VC_LOCK(sc);
-	val = bcm2835_cpufreq_get_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_SDRAM_I);
+	val = bcm2835_cpufreq_get_voltage(sc,
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_I);
 	VC_UNLOCK(sc);
 	if (val == MSG_ERROR)
 		return (EIO);
@@ -933,8 +878,8 @@ sysctl_bcm2835_cpufreq_voltage_sdram_i(SYSCTL_HANDLER_ARGS)
 	sc->voltage_sdram_i = val;
 
 	VC_LOCK(sc);
-	err = bcm2835_cpufreq_set_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_SDRAM_I,
-	    sc->voltage_sdram_i);
+	err = bcm2835_cpufreq_set_voltage(sc,
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_I, sc->voltage_sdram_i);
 	VC_UNLOCK(sc);
 	if (err == MSG_ERROR) {
 		device_printf(sc->dev, "set voltage sdram_i error\n");
@@ -954,7 +899,8 @@ sysctl_bcm2835_cpufreq_voltage_sdram_p(SYSCTL_HANDLER_ARGS)
 
 	/* get realtime value */
 	VC_LOCK(sc);
-	val = bcm2835_cpufreq_get_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_SDRAM_P);
+	val = bcm2835_cpufreq_get_voltage(sc,
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_P);
 	VC_UNLOCK(sc);
 	if (val == MSG_ERROR)
 		return (EIO);
@@ -969,8 +915,8 @@ sysctl_bcm2835_cpufreq_voltage_sdram_p(SYSCTL_HANDLER_ARGS)
 	sc->voltage_sdram_p = val;
 
 	VC_LOCK(sc);
-	err = bcm2835_cpufreq_set_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_SDRAM_P,
-	    sc->voltage_sdram_p);
+	err = bcm2835_cpufreq_set_voltage(sc,
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_P, sc->voltage_sdram_p);
 	VC_UNLOCK(sc);
 	if (err == MSG_ERROR) {
 		device_printf(sc->dev, "set voltage sdram_p error\n");
@@ -1002,22 +948,22 @@ sysctl_bcm2835_cpufreq_voltage_sdram(SYSCTL_HANDLER_ARGS)
 	sc->voltage_sdram = val;
 
 	VC_LOCK(sc);
-	err = bcm2835_cpufreq_set_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_SDRAM_C,
-	    val);
+	err = bcm2835_cpufreq_set_voltage(sc,
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_C, val);
 	if (err == MSG_ERROR) {
 		VC_UNLOCK(sc);
 		device_printf(sc->dev, "set voltage sdram_c error\n");
 		return (EIO);
 	}
-	err = bcm2835_cpufreq_set_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_SDRAM_I,
-	    val);
+	err = bcm2835_cpufreq_set_voltage(sc,
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_I, val);
 	if (err == MSG_ERROR) {
 		VC_UNLOCK(sc);
 		device_printf(sc->dev, "set voltage sdram_i error\n");
 		return (EIO);
 	}
-	err = bcm2835_cpufreq_set_voltage(sc, BCM2835_MBOX_VOLTAGE_ID_SDRAM_P,
-	    val);
+	err = bcm2835_cpufreq_set_voltage(sc,
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_P, val);
 	if (err == MSG_ERROR) {
 		VC_UNLOCK(sc);
 		device_printf(sc->dev, "set voltage sdram_p error\n");
@@ -1097,42 +1043,42 @@ bcm2835_cpufreq_init(void *arg)
 
 	/* current clock */
 	arm_freq = bcm2835_cpufreq_get_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_ARM);
+	    BCM2835_FIRMWARE_CLOCK_ID_ARM);
 	core_freq = bcm2835_cpufreq_get_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_CORE);
+	    BCM2835_FIRMWARE_CLOCK_ID_CORE);
 	sdram_freq = bcm2835_cpufreq_get_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_SDRAM);
+	    BCM2835_FIRMWARE_CLOCK_ID_SDRAM);
 
 	/* max/min clock */
 	arm_max_freq = bcm2835_cpufreq_get_max_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_ARM);
+	    BCM2835_FIRMWARE_CLOCK_ID_ARM);
 	arm_min_freq = bcm2835_cpufreq_get_min_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_ARM);
+	    BCM2835_FIRMWARE_CLOCK_ID_ARM);
 	core_max_freq = bcm2835_cpufreq_get_max_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_CORE);
+	    BCM2835_FIRMWARE_CLOCK_ID_CORE);
 	core_min_freq = bcm2835_cpufreq_get_min_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_CORE);
+	    BCM2835_FIRMWARE_CLOCK_ID_CORE);
 	sdram_max_freq = bcm2835_cpufreq_get_max_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_SDRAM);
+	    BCM2835_FIRMWARE_CLOCK_ID_SDRAM);
 	sdram_min_freq = bcm2835_cpufreq_get_min_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_SDRAM);
+	    BCM2835_FIRMWARE_CLOCK_ID_SDRAM);
 
 	/* turbo mode */
 	turbo = bcm2835_cpufreq_get_turbo(sc);
 	if (turbo > 0)
-		sc->turbo_mode = BCM2835_MBOX_TURBO_ON;
+		sc->turbo_mode = BCM2835_FIRMWARE_TURBO_ON;
 	else
-		sc->turbo_mode = BCM2835_MBOX_TURBO_OFF;
+		sc->turbo_mode = BCM2835_FIRMWARE_TURBO_OFF;
 
 	/* voltage */
 	voltage_core = bcm2835_cpufreq_get_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_CORE);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_CORE);
 	voltage_sdram_c = bcm2835_cpufreq_get_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_SDRAM_C);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_C);
 	voltage_sdram_i = bcm2835_cpufreq_get_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_SDRAM_I);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_I);
 	voltage_sdram_p = bcm2835_cpufreq_get_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_SDRAM_P);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_P);
 
 	/* current values (offset from 1.2V) */
 	sc->voltage_core = voltage_core;
@@ -1143,21 +1089,21 @@ bcm2835_cpufreq_init(void *arg)
 
 	/* max/min voltage */
 	max_voltage_core = bcm2835_cpufreq_get_max_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_CORE);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_CORE);
 	min_voltage_core = bcm2835_cpufreq_get_min_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_CORE);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_CORE);
 	max_voltage_sdram_c = bcm2835_cpufreq_get_max_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_SDRAM_C);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_C);
 	max_voltage_sdram_i = bcm2835_cpufreq_get_max_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_SDRAM_I);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_I);
 	max_voltage_sdram_p = bcm2835_cpufreq_get_max_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_SDRAM_P);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_P);
 	min_voltage_sdram_c = bcm2835_cpufreq_get_min_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_SDRAM_C);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_C);
 	min_voltage_sdram_i = bcm2835_cpufreq_get_min_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_SDRAM_I);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_I);
 	min_voltage_sdram_p = bcm2835_cpufreq_get_min_voltage(sc,
-	    BCM2835_MBOX_VOLTAGE_ID_SDRAM_P);
+	    BCM2835_FIRMWARE_VOLTAGE_ID_SDRAM_P);
 
 	/* temperature */
 	temperature = bcm2835_cpufreq_get_temperature(sc);
@@ -1168,7 +1114,7 @@ bcm2835_cpufreq_init(void *arg)
 		device_printf(sc->dev,
 		    "current ARM %dMHz, Core %dMHz, SDRAM %dMHz, Turbo %s\n",
 		    HZ2MHZ(arm_freq), HZ2MHZ(core_freq), HZ2MHZ(sdram_freq),
-		    (sc->turbo_mode == BCM2835_MBOX_TURBO_ON) ? "ON" : "OFF");
+		    (sc->turbo_mode == BCM2835_FIRMWARE_TURBO_ON) ? "ON":"OFF");
 
 		device_printf(sc->dev,
 		    "max/min ARM %d/%dMHz, Core %d/%dMHz, SDRAM %d/%dMHz\n",
@@ -1202,7 +1148,7 @@ bcm2835_cpufreq_init(void *arg)
 		device_printf(sc->dev,
 		    "ARM %dMHz, Core %dMHz, SDRAM %dMHz, Turbo %s\n",
 		    HZ2MHZ(arm_freq), HZ2MHZ(core_freq), HZ2MHZ(sdram_freq),
-		    (sc->turbo_mode == BCM2835_MBOX_TURBO_ON) ? "ON" : "OFF");
+		    (sc->turbo_mode == BCM2835_FIRMWARE_TURBO_ON) ? "ON":"OFF");
 	}
 
 	/* keep in softc (MHz/mV) */
@@ -1216,25 +1162,25 @@ bcm2835_cpufreq_init(void *arg)
 	sc->min_voltage_core = OFFSET2MVOLT(min_voltage_core);
 
 	/* if turbo is on, set to max values */
-	if (sc->turbo_mode == BCM2835_MBOX_TURBO_ON) {
-		bcm2835_cpufreq_set_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_ARM,
-		    arm_max_freq);
+	if (sc->turbo_mode == BCM2835_FIRMWARE_TURBO_ON) {
+		bcm2835_cpufreq_set_clock_rate(sc,
+		    BCM2835_FIRMWARE_CLOCK_ID_ARM, arm_max_freq);
 		DELAY(TRANSITION_LATENCY);
-		bcm2835_cpufreq_set_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_CORE,
-		    core_max_freq);
+		bcm2835_cpufreq_set_clock_rate(sc,
+		    BCM2835_FIRMWARE_CLOCK_ID_CORE, core_max_freq);
 		DELAY(TRANSITION_LATENCY);
 		bcm2835_cpufreq_set_clock_rate(sc,
-		    BCM2835_MBOX_CLOCK_ID_SDRAM, sdram_max_freq);
+		    BCM2835_FIRMWARE_CLOCK_ID_SDRAM, sdram_max_freq);
 		DELAY(TRANSITION_LATENCY);
 	} else {
-		bcm2835_cpufreq_set_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_ARM,
-		    arm_min_freq);
+		bcm2835_cpufreq_set_clock_rate(sc,
+		    BCM2835_FIRMWARE_CLOCK_ID_ARM, arm_min_freq);
 		DELAY(TRANSITION_LATENCY);
-		bcm2835_cpufreq_set_clock_rate(sc, BCM2835_MBOX_CLOCK_ID_CORE,
-		    core_min_freq);
+		bcm2835_cpufreq_set_clock_rate(sc,
+		    BCM2835_FIRMWARE_CLOCK_ID_CORE, core_min_freq);
 		DELAY(TRANSITION_LATENCY);
 		bcm2835_cpufreq_set_clock_rate(sc,
-		    BCM2835_MBOX_CLOCK_ID_SDRAM, sdram_min_freq);
+		    BCM2835_FIRMWARE_CLOCK_ID_SDRAM, sdram_min_freq);
 		DELAY(TRANSITION_LATENCY);
 	}
 
@@ -1297,6 +1243,12 @@ bcm2835_cpufreq_attach(device_t dev)
 	/* set self dev */
 	sc = device_get_softc(dev);
 	sc->dev = dev;
+	sc->firmware = devclass_get_device(
+	    devclass_find("bcm2835_firmware"), 0);
+	if (sc->firmware == NULL) {
+		device_printf(dev, "Unable to find firmware device\n");
+		return (ENXIO);
+	}
 
 	/* initial values */
 	sc->arm_max_freq = -1;
@@ -1430,7 +1382,7 @@ bcm2835_cpufreq_set(device_t dev, const struct cf_setting *cf)
 
 	/* adjust min freq */
 	min_freq = sc->arm_min_freq;
-	if (sc->turbo_mode != BCM2835_MBOX_TURBO_ON)
+	if (sc->turbo_mode != BCM2835_FIRMWARE_TURBO_ON)
 		if (min_freq > cpufreq_lowest_freq)
 			min_freq = cpufreq_lowest_freq;
 
@@ -1441,28 +1393,28 @@ bcm2835_cpufreq_set(device_t dev, const struct cf_setting *cf)
 	VC_LOCK(sc);
 #ifdef DEBUG
 	cur_freq = bcm2835_cpufreq_get_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_ARM);
+	    BCM2835_FIRMWARE_CLOCK_ID_ARM);
 #endif
 	resp_freq = bcm2835_cpufreq_set_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_ARM, rate_hz);
+	    BCM2835_FIRMWARE_CLOCK_ID_ARM, rate_hz);
 	DELAY(TRANSITION_LATENCY);
 	arm_freq = bcm2835_cpufreq_get_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_ARM);
+	    BCM2835_FIRMWARE_CLOCK_ID_ARM);
 
 	/*
 	 * if non-turbo and lower than or equal min_freq,
 	 * clock down core and sdram to default first.
 	 */
-	if (sc->turbo_mode != BCM2835_MBOX_TURBO_ON) {
+	if (sc->turbo_mode != BCM2835_FIRMWARE_TURBO_ON) {
 		core_freq = bcm2835_cpufreq_get_clock_rate(sc,
-		    BCM2835_MBOX_CLOCK_ID_CORE);
+		    BCM2835_FIRMWARE_CLOCK_ID_CORE);
 		if (rate_hz > MHZ2HZ(sc->arm_min_freq)) {
 			bcm2835_cpufreq_set_clock_rate(sc,
-			    BCM2835_MBOX_CLOCK_ID_CORE,
+			    BCM2835_FIRMWARE_CLOCK_ID_CORE,
 			    MHZ2HZ(sc->core_max_freq));
 			DELAY(TRANSITION_LATENCY);
 			bcm2835_cpufreq_set_clock_rate(sc,
-			    BCM2835_MBOX_CLOCK_ID_SDRAM,
+			    BCM2835_FIRMWARE_CLOCK_ID_SDRAM,
 			    MHZ2HZ(sc->sdram_max_freq));
 			DELAY(TRANSITION_LATENCY);
 		} else {
@@ -1471,20 +1423,20 @@ bcm2835_cpufreq_set(device_t dev, const struct cf_setting *cf)
 				/* first, down to 250, then down to min */
 				DELAY(TRANSITION_LATENCY);
 				bcm2835_cpufreq_set_clock_rate(sc,
-				    BCM2835_MBOX_CLOCK_ID_CORE,
+				    BCM2835_FIRMWARE_CLOCK_ID_CORE,
 				    MHZ2HZ(DEFAULT_CORE_FREQUENCY));
 				DELAY(TRANSITION_LATENCY);
 				/* reset core voltage */
 				bcm2835_cpufreq_set_voltage(sc,
-				    BCM2835_MBOX_VOLTAGE_ID_CORE, 0);
+				    BCM2835_FIRMWARE_VOLTAGE_ID_CORE, 0);
 				DELAY(TRANSITION_LATENCY);
 			}
 			bcm2835_cpufreq_set_clock_rate(sc,
-			    BCM2835_MBOX_CLOCK_ID_CORE,
+			    BCM2835_FIRMWARE_CLOCK_ID_CORE,
 			    MHZ2HZ(sc->core_min_freq));
 			DELAY(TRANSITION_LATENCY);
 			bcm2835_cpufreq_set_clock_rate(sc,
-			    BCM2835_MBOX_CLOCK_ID_SDRAM,
+			    BCM2835_FIRMWARE_CLOCK_ID_SDRAM,
 			    MHZ2HZ(sc->sdram_min_freq));
 			DELAY(TRANSITION_LATENCY);
 		}
@@ -1517,7 +1469,7 @@ bcm2835_cpufreq_get(device_t dev, struct cf_setting *cf)
 	/* get cuurent value */
 	VC_LOCK(sc);
 	arm_freq = bcm2835_cpufreq_get_clock_rate(sc,
-	    BCM2835_MBOX_CLOCK_ID_ARM);
+	    BCM2835_FIRMWARE_CLOCK_ID_ARM);
 	VC_UNLOCK(sc);
 	if (arm_freq < 0) {
 		device_printf(dev, "can't get clock\n");
@@ -1557,7 +1509,7 @@ bcm2835_cpufreq_make_freq_list(device_t dev, struct cf_setting *sets,
 		freq = min_freq;
 
 	/* if non-turbo, add extra low freq */
-	if (sc->turbo_mode != BCM2835_MBOX_TURBO_ON)
+	if (sc->turbo_mode != BCM2835_FIRMWARE_TURBO_ON)
 		if (min_freq > cpufreq_lowest_freq)
 			min_freq = cpufreq_lowest_freq;
 
@@ -1654,3 +1606,4 @@ static driver_t bcm2835_cpufreq_driver = {
 
 DRIVER_MODULE(bcm2835_cpufreq, cpu, bcm2835_cpufreq_driver,
     bcm2835_cpufreq_devclass, 0, 0);
+MODULE_DEPEND(bcm2835_cpufreq, bcm2835_firmware, 1, 1, 1);