1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2012 Alexander Rybalko <ray@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/param.h>
30#include <sys/bus.h>
31#include <sys/eventhandler.h>
32#include <sys/kernel.h>
33#include <sys/lock.h>
34#include <sys/module.h>
35#include <sys/mutex.h>
36#include <sys/reboot.h>
37#include <sys/rman.h>
38#include <sys/systm.h>
39#include <sys/watchdog.h>
40
41#include <dev/ofw/openfirm.h>
42#include <dev/ofw/ofw_bus.h>
43#include <dev/ofw/ofw_bus_subr.h>
44
45#include <machine/bus.h>
46#include <machine/machdep.h>
47
48#include <arm/broadcom/bcm2835/bcm2835_wdog.h>
49
50#define	BCM2835_PASSWORD	0x5a
51
52#define BCM2835_WDOG_RESET	0
53#define BCM2835_PASSWORD_MASK	0xff000000
54#define BCM2835_PASSWORD_SHIFT	24
55#define BCM2835_WDOG_TIME_MASK	0x000fffff
56#define BCM2835_WDOG_TIME_SHIFT	0
57
58#define	READ(_sc, _r) bus_space_read_4((_sc)->bst, (_sc)->bsh, (_r) + (_sc)->regs_offset)
59#define	WRITE(_sc, _r, _v) bus_space_write_4((_sc)->bst, (_sc)->bsh, (_r) + (_sc)->regs_offset, (_v))
60
61#define BCM2835_RSTC_WRCFG_CLR		0xffffffcf
62#define BCM2835_RSTC_WRCFG_SET		0x00000030
63#define BCM2835_RSTC_WRCFG_FULL_RESET	0x00000020
64#define BCM2835_RSTC_RESET		0x00000102
65
66#define	BCM2835_RSTC_REG	0x00
67#define	BCM2835_RSTS_REG	0x04
68#define	BCM2835_WDOG_REG	0x08
69
70static struct bcmwd_softc *bcmwd_lsc = NULL;
71
72struct bcmwd_softc {
73	device_t		dev;
74	struct resource *	res;
75	bus_space_tag_t		bst;
76	bus_space_handle_t	bsh;
77	int			wdog_armed;
78	int			wdog_period;
79	char			wdog_passwd;
80	struct mtx		mtx;
81	int			regs_offset;
82};
83
84#define	BSD_DTB		1
85#define	UPSTREAM_DTB	2
86#define	UPSTREAM_DTB_REGS_OFFSET	0x1c
87
88static struct ofw_compat_data compat_data[] = {
89	{"broadcom,bcm2835-wdt",	BSD_DTB},
90	{"brcm,bcm2835-pm-wdt",		UPSTREAM_DTB},
91	{"brcm,bcm2835-pm",		UPSTREAM_DTB},
92	{NULL,				0}
93};
94
95static void bcmwd_watchdog_fn(void *private, u_int cmd, int *error);
96static void bcmwd_reboot_system(void *, int);
97
98static int
99bcmwd_probe(device_t dev)
100{
101
102	if (!ofw_bus_status_okay(dev))
103		return (ENXIO);
104
105	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
106		return (ENXIO);
107
108	device_set_desc(dev, "BCM2708/2835 Watchdog");
109
110	return (BUS_PROBE_DEFAULT);
111}
112
113static int
114bcmwd_attach(device_t dev)
115{
116	struct bcmwd_softc *sc;
117	int rid;
118
119	if (bcmwd_lsc != NULL)
120		return (ENXIO);
121
122	sc = device_get_softc(dev);
123	sc->wdog_period = 7;
124	sc->wdog_passwd = BCM2835_PASSWORD;
125	sc->wdog_armed = 0;
126	sc->dev = dev;
127
128	rid = 0;
129	sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
130	if (sc->res == NULL) {
131		device_printf(dev, "could not allocate memory resource\n");
132		return (ENXIO);
133	}
134
135	sc->bst = rman_get_bustag(sc->res);
136	sc->bsh = rman_get_bushandle(sc->res);
137
138	/* compensate base address difference */
139	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data
140	   == UPSTREAM_DTB)
141		sc->regs_offset = UPSTREAM_DTB_REGS_OFFSET;
142
143	bcmwd_lsc = sc;
144	mtx_init(&sc->mtx, "BCM2835 Watchdog", "bcmwd", MTX_DEF);
145	EVENTHANDLER_REGISTER(watchdog_list, bcmwd_watchdog_fn, sc, 0);
146
147	/*
148	 * Handle reboot events. This needs to happen with slightly greater
149	 * priority than the PSCI handler, since PSCI reset is not properly
150	 * implemented on the Pi and it just puts the Pi into a halt
151	 * state.
152	 */
153	EVENTHANDLER_REGISTER(shutdown_final, bcmwd_reboot_system, sc,
154	    SHUTDOWN_PRI_LAST-1);
155
156	return (0);
157}
158
159static void
160bcmwd_watchdog_fn(void *private, u_int cmd, int *error)
161{
162	struct bcmwd_softc *sc;
163	uint64_t sec;
164	uint32_t ticks, reg;
165
166	sc = private;
167	mtx_lock(&sc->mtx);
168
169	cmd &= WD_INTERVAL;
170
171	if (cmd > 0) {
172		sec = ((uint64_t)1 << (cmd & WD_INTERVAL)) / 1000000000;
173		if (sec == 0 || sec > 15) {
174			/*
175			 * Can't arm
176			 * disable watchdog as watchdog(9) requires
177			 */
178			device_printf(sc->dev,
179			    "Can't arm, timeout must be between 1-15 seconds\n");
180			WRITE(sc, BCM2835_RSTC_REG,
181			    (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) |
182			    BCM2835_RSTC_RESET);
183			mtx_unlock(&sc->mtx);
184			*error = EINVAL;
185			return;
186		}
187
188		ticks = (sec << 16) & BCM2835_WDOG_TIME_MASK;
189		reg = (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) | ticks;
190		WRITE(sc, BCM2835_WDOG_REG, reg);
191
192		reg = READ(sc, BCM2835_RSTC_REG);
193		reg &= BCM2835_RSTC_WRCFG_CLR;
194		reg |= BCM2835_RSTC_WRCFG_FULL_RESET;
195		reg |= (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT);
196		WRITE(sc, BCM2835_RSTC_REG, reg);
197
198		*error = 0;
199	}
200	else
201		WRITE(sc, BCM2835_RSTC_REG,
202		    (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) |
203		    BCM2835_RSTC_RESET);
204
205	mtx_unlock(&sc->mtx);
206}
207
208void
209bcmwd_watchdog_reset(void)
210{
211
212	if (bcmwd_lsc == NULL)
213		return;
214
215	WRITE(bcmwd_lsc, BCM2835_WDOG_REG,
216	    (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) | 10);
217
218	WRITE(bcmwd_lsc, BCM2835_RSTC_REG,
219	    (READ(bcmwd_lsc, BCM2835_RSTC_REG) & BCM2835_RSTC_WRCFG_CLR) |
220		(BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) |
221		BCM2835_RSTC_WRCFG_FULL_RESET);
222}
223
224static void
225bcmwd_reboot_system(void *sc, int howto)
226{
227	int cmd, error = 0;
228
229	/* Only handle reset. */
230	if (howto & RB_HALT || howto & RB_POWEROFF)
231		return;
232
233	printf("Resetting system ... ");
234
235	cmd = WD_TO_1SEC;
236	bcmwd_watchdog_fn(sc, cmd, &error);
237
238	/* Wait for watchdog timeout. */
239	DELAY(2000000);
240
241	/* Not reached ... one hopes. */
242	printf("failed to reset (errno %d).\n", error);
243}
244
245static device_method_t bcmwd_methods[] = {
246	DEVMETHOD(device_probe, bcmwd_probe),
247	DEVMETHOD(device_attach, bcmwd_attach),
248
249	DEVMETHOD_END
250};
251
252static driver_t bcmwd_driver = {
253	"bcmwd",
254	bcmwd_methods,
255	sizeof(struct bcmwd_softc),
256};
257
258DRIVER_MODULE(bcmwd, simplebus, bcmwd_driver, 0, 0);
259