1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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#include <sys/cdefs.h>
29__FBSDID("$FreeBSD$");
30
31#include <sys/param.h>
32#include <sys/bus.h>
33#include <sys/eventhandler.h>
34#include <sys/kernel.h>
35#include <sys/lock.h>
36#include <sys/module.h>
37#include <sys/mutex.h>
38#include <sys/reboot.h>
39#include <sys/rman.h>
40#include <sys/systm.h>
41#include <sys/watchdog.h>
42
43#include <dev/ofw/openfirm.h>
44#include <dev/ofw/ofw_bus.h>
45#include <dev/ofw/ofw_bus_subr.h>
46
47#include <machine/bus.h>
48#include <machine/machdep.h>
49
50#include <arm/broadcom/bcm2835/bcm2835_wdog.h>
51
52#define	BCM2835_PASSWORD	0x5a
53
54#define BCM2835_WDOG_RESET	0
55#define BCM2835_PASSWORD_MASK	0xff000000
56#define BCM2835_PASSWORD_SHIFT	24
57#define BCM2835_WDOG_TIME_MASK	0x000fffff
58#define BCM2835_WDOG_TIME_SHIFT	0
59
60#define	READ(_sc, _r) bus_space_read_4((_sc)->bst, (_sc)->bsh, (_r) + (_sc)->regs_offset)
61#define	WRITE(_sc, _r, _v) bus_space_write_4((_sc)->bst, (_sc)->bsh, (_r) + (_sc)->regs_offset, (_v))
62
63#define BCM2835_RSTC_WRCFG_CLR		0xffffffcf
64#define BCM2835_RSTC_WRCFG_SET		0x00000030
65#define BCM2835_RSTC_WRCFG_FULL_RESET	0x00000020
66#define BCM2835_RSTC_RESET		0x00000102
67
68#define	BCM2835_RSTC_REG	0x00
69#define	BCM2835_RSTS_REG	0x04
70#define	BCM2835_WDOG_REG	0x08
71
72static struct bcmwd_softc *bcmwd_lsc = NULL;
73
74struct bcmwd_softc {
75	device_t		dev;
76	struct resource *	res;
77	bus_space_tag_t		bst;
78	bus_space_handle_t	bsh;
79	int			wdog_armed;
80	int			wdog_period;
81	char			wdog_passwd;
82	struct mtx		mtx;
83	int			regs_offset;
84};
85
86#define	BSD_DTB		1
87#define	UPSTREAM_DTB	2
88#define	UPSTREAM_DTB_REGS_OFFSET	0x1c
89
90static struct ofw_compat_data compat_data[] = {
91	{"broadcom,bcm2835-wdt",	BSD_DTB},
92	{"brcm,bcm2835-pm-wdt",		UPSTREAM_DTB},
93	{"brcm,bcm2835-pm",		UPSTREAM_DTB},
94	{NULL,				0}
95};
96
97static void bcmwd_watchdog_fn(void *private, u_int cmd, int *error);
98static void bcmwd_reboot_system(void *, int);
99
100static int
101bcmwd_probe(device_t dev)
102{
103
104	if (!ofw_bus_status_okay(dev))
105		return (ENXIO);
106
107	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
108		return (ENXIO);
109
110	device_set_desc(dev, "BCM2708/2835 Watchdog");
111
112	return (BUS_PROBE_DEFAULT);
113}
114
115static int
116bcmwd_attach(device_t dev)
117{
118	struct bcmwd_softc *sc;
119	int rid;
120
121	if (bcmwd_lsc != NULL)
122		return (ENXIO);
123
124	sc = device_get_softc(dev);
125	sc->wdog_period = 7;
126	sc->wdog_passwd = BCM2835_PASSWORD;
127	sc->wdog_armed = 0;
128	sc->dev = dev;
129
130	rid = 0;
131	sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
132	if (sc->res == NULL) {
133		device_printf(dev, "could not allocate memory resource\n");
134		return (ENXIO);
135	}
136
137	sc->bst = rman_get_bustag(sc->res);
138	sc->bsh = rman_get_bushandle(sc->res);
139
140	/* compensate base address difference */
141	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data
142	   == UPSTREAM_DTB)
143		sc->regs_offset = UPSTREAM_DTB_REGS_OFFSET;
144
145	bcmwd_lsc = sc;
146	mtx_init(&sc->mtx, "BCM2835 Watchdog", "bcmwd", MTX_DEF);
147	EVENTHANDLER_REGISTER(watchdog_list, bcmwd_watchdog_fn, sc, 0);
148
149	/*
150	 * Handle reboot events. This needs to happen with slightly greater
151	 * priority than the PSCI handler, since PSCI reset is not properly
152	 * implemented on the Pi and it just puts the Pi into a halt
153	 * state.
154	 */
155	EVENTHANDLER_REGISTER(shutdown_final, bcmwd_reboot_system, sc,
156	    SHUTDOWN_PRI_LAST-1);
157
158	return (0);
159}
160
161static void
162bcmwd_watchdog_fn(void *private, u_int cmd, int *error)
163{
164	struct bcmwd_softc *sc;
165	uint64_t sec;
166	uint32_t ticks, reg;
167
168	sc = private;
169	mtx_lock(&sc->mtx);
170
171	cmd &= WD_INTERVAL;
172
173	if (cmd > 0) {
174		sec = ((uint64_t)1 << (cmd & WD_INTERVAL)) / 1000000000;
175		if (sec == 0 || sec > 15) {
176			/*
177			 * Can't arm
178			 * disable watchdog as watchdog(9) requires
179			 */
180			device_printf(sc->dev,
181			    "Can't arm, timeout must be between 1-15 seconds\n");
182			WRITE(sc, BCM2835_RSTC_REG,
183			    (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) |
184			    BCM2835_RSTC_RESET);
185			mtx_unlock(&sc->mtx);
186			*error = EINVAL;
187			return;
188		}
189
190		ticks = (sec << 16) & BCM2835_WDOG_TIME_MASK;
191		reg = (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) | ticks;
192		WRITE(sc, BCM2835_WDOG_REG, reg);
193
194		reg = READ(sc, BCM2835_RSTC_REG);
195		reg &= BCM2835_RSTC_WRCFG_CLR;
196		reg |= BCM2835_RSTC_WRCFG_FULL_RESET;
197		reg |= (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT);
198		WRITE(sc, BCM2835_RSTC_REG, reg);
199
200		*error = 0;
201	}
202	else
203		WRITE(sc, BCM2835_RSTC_REG,
204		    (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) |
205		    BCM2835_RSTC_RESET);
206
207	mtx_unlock(&sc->mtx);
208}
209
210void
211bcmwd_watchdog_reset(void)
212{
213
214	if (bcmwd_lsc == NULL)
215		return;
216
217	WRITE(bcmwd_lsc, BCM2835_WDOG_REG,
218	    (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) | 10);
219
220	WRITE(bcmwd_lsc, BCM2835_RSTC_REG,
221	    (READ(bcmwd_lsc, BCM2835_RSTC_REG) & BCM2835_RSTC_WRCFG_CLR) |
222		(BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) |
223		BCM2835_RSTC_WRCFG_FULL_RESET);
224}
225
226static void
227bcmwd_reboot_system(void *sc, int howto)
228{
229	int cmd, error = 0;
230
231	/* Only handle reset. */
232	if (howto & RB_HALT || howto & RB_POWEROFF)
233		return;
234
235	printf("Resetting system ... ");
236
237	cmd = WD_TO_1SEC;
238	bcmwd_watchdog_fn(sc, cmd, &error);
239
240	/* Wait for watchdog timeout. */
241	DELAY(2000000);
242
243	/* Not reached ... one hopes. */
244	printf("failed to reset (errno %d).\n", error);
245}
246
247static device_method_t bcmwd_methods[] = {
248	DEVMETHOD(device_probe, bcmwd_probe),
249	DEVMETHOD(device_attach, bcmwd_attach),
250
251	DEVMETHOD_END
252};
253
254static driver_t bcmwd_driver = {
255	"bcmwd",
256	bcmwd_methods,
257	sizeof(struct bcmwd_softc),
258};
259static devclass_t bcmwd_devclass;
260
261DRIVER_MODULE(bcmwd, simplebus, bcmwd_driver, bcmwd_devclass, 0, 0);
262