imx_wdog.c revision 266152 
1/*-
2 * Copyright (c) 2012, 2013 The FreeBSD Foundation
3 * All rights reserved.
4 *
5 * This software was developed by Oleksandr Rybalko under sponsorship
6 * from the FreeBSD Foundation.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1.	Redistributions of source code must retain the above copyright
12 *	notice, this list of conditions and the following disclaimer.
13 * 2.	Redistributions in binary form must reproduce the above copyright
14 *	notice, this list of conditions and the following disclaimer in the
15 *	documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: stable/10/sys/arm/freescale/imx/imx_wdog.c 266152 2014-05-15 16:11:06Z ian $");
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/kernel.h>
36#include <sys/module.h>
37#include <sys/time.h>
38#include <sys/bus.h>
39#include <sys/resource.h>
40#include <sys/rman.h>
41#include <sys/watchdog.h>
42
43#include <machine/bus.h>
44#include <machine/intr.h>
45
46#include <dev/fdt/fdt_common.h>
47#include <dev/ofw/openfirm.h>
48#include <dev/ofw/ofw_bus.h>
49#include <dev/ofw/ofw_bus_subr.h>
50#include <machine/fdt.h>
51
52#include <arm/freescale/imx/imx_wdogreg.h>
53
54struct imx_wdog_softc {
55	struct mtx		sc_mtx;
56	device_t		sc_dev;
57	bus_space_tag_t		sc_bst;
58	bus_space_handle_t	sc_bsh;
59	struct resource		*sc_res[2];
60	uint32_t		sc_timeout;
61};
62
63static struct resource_spec imx_wdog_spec[] = {
64	{ SYS_RES_MEMORY,	0,	RF_ACTIVE },
65	{ SYS_RES_IRQ,		0,	RF_ACTIVE },
66	{ -1, 0 }
67};
68
69static void	imx_watchdog(void *, u_int, int *);
70static int	imx_wdog_probe(device_t);
71static int	imx_wdog_attach(device_t);
72
73static device_method_t imx_wdog_methods[] = {
74	DEVMETHOD(device_probe,		imx_wdog_probe),
75	DEVMETHOD(device_attach,	imx_wdog_attach),
76	DEVMETHOD_END
77};
78
79static driver_t imx_wdog_driver = {
80	"imx_wdog",
81	imx_wdog_methods,
82	sizeof(struct imx_wdog_softc),
83};
84static devclass_t imx_wdog_devclass;
85DRIVER_MODULE(imx_wdog, simplebus, imx_wdog_driver, imx_wdog_devclass, 0, 0);
86
87
88static void
89imx_watchdog(void *arg, u_int cmd, int *error)
90{
91	struct imx_wdog_softc *sc;
92	uint16_t reg;
93	int timeout;
94
95	sc = arg;
96	mtx_lock(&sc->sc_mtx);
97
98	/* Refresh counter, since we feels good */
99	WRITE(sc, WDOG_SR_REG, WDOG_SR_STEP1);
100	WRITE(sc, WDOG_SR_REG, WDOG_SR_STEP2);
101
102	/* We don't require precession, so "-10" (/1024) is ok */
103	timeout = (1 << ((cmd & WD_INTERVAL) - 10)) / 1000000;
104	if (timeout > 1 && timeout < 128) {
105		if (timeout != sc->sc_timeout) {
106			device_printf(sc->sc_dev,
107			    "WARNING: watchdog can't be disabled!!!");
108			sc->sc_timeout = timeout;
109			reg = READ(sc, WDOG_CR_REG);
110			reg &= ~WDOG_CR_WT_MASK;
111			reg |= (timeout << (WDOG_CR_WT_SHIFT + 1)) &
112			    WDOG_CR_WT_MASK;
113			WRITE(sc, WDOG_CR_REG, reg);
114			/* Refresh counter */
115			WRITE(sc, WDOG_SR_REG, WDOG_SR_STEP1);
116			WRITE(sc, WDOG_SR_REG, WDOG_SR_STEP2);
117			*error = 0;
118		} else {
119			*error = EOPNOTSUPP;
120		}
121	} else {
122		device_printf(sc->sc_dev, "Can not be disabled.\n");
123		*error = EOPNOTSUPP;
124	}
125	mtx_unlock(&sc->sc_mtx);
126
127}
128
129static int
130imx_wdog_probe(device_t dev)
131{
132
133	if (!ofw_bus_status_okay(dev))
134		return (ENXIO);
135
136	if (!ofw_bus_is_compatible(dev, "fsl,imx51-wdt") &&
137	    !ofw_bus_is_compatible(dev, "fsl,imx53-wdt"))
138		return (ENXIO);
139
140	device_set_desc(dev, "Freescale i.MX5xx Watchdog Timer");
141	return (0);
142}
143
144static int
145imx_wdog_attach(device_t dev)
146{
147	struct imx_wdog_softc *sc;
148
149	sc = device_get_softc(dev);
150	sc->sc_dev = dev;
151
152	if (bus_alloc_resources(dev, imx_wdog_spec, sc->sc_res)) {
153		device_printf(dev, "could not allocate resources\n");
154		return (ENXIO);
155	}
156
157	mtx_init(&sc->sc_mtx, device_get_nameunit(dev), "imx_wdt", MTX_DEF);
158
159	sc->sc_dev = dev;
160	sc->sc_bst = rman_get_bustag(sc->sc_res[0]);
161	sc->sc_bsh = rman_get_bushandle(sc->sc_res[0]);
162
163	/* TODO: handle interrupt */
164
165	EVENTHANDLER_REGISTER(watchdog_list, imx_watchdog, sc, 0);
166	return (0);
167}
168