alpine_nb_service.c

/*-
 * Copyright (c) 2015,2016 Annapurna Labs Ltd. and affiliates
 * All rights reserved.
 *
 * Developed by Semihalf.
 *
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/param.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/rman.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/resource.h>
#include <sys/systm.h>

#include <machine/bus.h>
#include <dev/ofw/ofw_bus_subr.h>

#define	AL_NB_ACF_MISC_OFFSET			0xD0
#define	AL_NB_ACF_MISC_READ_BYPASS		(1 << 30)

static struct resource_spec nb_service_spec[] = {
	{ SYS_RES_MEMORY,	0,	RF_ACTIVE },
	{ -1, 0 }
};

struct nb_service_softc {
	struct resource	*res;
};

static int nb_service_probe(device_t dev);
static int nb_service_attach(device_t dev);
static int nb_service_detach(device_t dev);

static device_method_t nb_service_methods[] = {
	DEVMETHOD(device_probe,		nb_service_probe),
	DEVMETHOD(device_attach,	nb_service_attach),
	DEVMETHOD(device_detach,	nb_service_detach),
	{ 0, 0 }
};

static driver_t nb_service_driver = {
	"nb_service",
	nb_service_methods,
	sizeof(struct nb_service_softc)
};

EARLY_DRIVER_MODULE(nb_service, simplebus, nb_service_driver, 0, 0,
    BUS_PASS_CPU + BUS_PASS_ORDER_MIDDLE);
EARLY_DRIVER_MODULE(nb_service, ofwbus, nb_service_driver, 0, 0,
    BUS_PASS_CPU + BUS_PASS_ORDER_MIDDLE);

static int
nb_service_probe(device_t dev)
{

	if (!ofw_bus_status_okay(dev))
		return (ENXIO);

	if (!ofw_bus_is_compatible(dev, "annapurna-labs,al-nb-service"))
		return (ENXIO);

	device_set_desc(dev, "Alpine North Bridge Service");

	return (BUS_PROBE_DEFAULT);
}

static int
nb_service_attach(device_t dev)
{
	struct nb_service_softc *sc;
	uint32_t val;
	int err;

	sc = device_get_softc(dev);

	err = bus_alloc_resources(dev, nb_service_spec, &sc->res);
	if (err != 0) {
		device_printf(dev, "could not allocate resources\n");
		return (err);
	}

	/* Do not allow reads to bypass writes to different addresses */
	val = bus_read_4(sc->res, AL_NB_ACF_MISC_OFFSET);
	val &= ~AL_NB_ACF_MISC_READ_BYPASS;
	bus_write_4(sc->res, AL_NB_ACF_MISC_OFFSET, val);

	return (0);
}

static int
nb_service_detach(device_t dev)
{
	struct nb_service_softc *sc;

	sc = device_get_softc(dev);

	bus_release_resources(dev, nb_service_spec, &sc->res);

	return (0);
}