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
70 static struct bcmwd_softc *bcmwd_lsc = NULL;
71
72 struct 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
88 static 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
95 static void bcmwd_watchdog_fn(void *private, u_int cmd, int *error);
96 static void bcmwd_reboot_system(void *, int);
97
98 static int
bcmwd_probe(device_t dev)99 bcmwd_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
113 static int
bcmwd_attach(device_t dev)114 bcmwd_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
159 static void
bcmwd_watchdog_fn(void * private,u_int cmd,int * error)160 bcmwd_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
208 void
bcmwd_watchdog_reset(void)209 bcmwd_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
224 static void
bcmwd_reboot_system(void * sc,int howto)225 bcmwd_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
245 static device_method_t bcmwd_methods[] = {
246 DEVMETHOD(device_probe, bcmwd_probe),
247 DEVMETHOD(device_attach, bcmwd_attach),
248
249 DEVMETHOD_END
250 };
251
252 static driver_t bcmwd_driver = {
253 "bcmwd",
254 bcmwd_methods,
255 sizeof(struct bcmwd_softc),
256 };
257
258 DRIVER_MODULE(bcmwd, simplebus, bcmwd_driver, 0, 0);
259