1 /*-
2 * Copyright (c) 2010 Greg Ansley. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 /*
27 * The SAM9 watchdog hardware can be programed only once. So we set the
28 * hardware watchdog to 16 s in wdt_attach and only reset it in the wdt_tick
29 * handler. The watchdog is halted in processor debug mode.
30 */
31
32 #include "opt_platform.h"
33
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36
37 #include <sys/param.h>
38 #include <sys/bus.h>
39 #include <sys/kdb.h>
40 #include <sys/kernel.h>
41 #include <sys/module.h>
42 #include <sys/systm.h>
43 #include <sys/watchdog.h>
44
45 #include <machine/bus.h>
46
47 #include <arm/at91/at91var.h>
48 #include <arm/at91/at91_wdtreg.h>
49
50 #ifdef FDT
51 #include <dev/fdt/fdt_common.h>
52 #include <dev/ofw/ofw_bus.h>
53 #include <dev/ofw/ofw_bus_subr.h>
54 #endif
55
56 struct wdt_softc {
57 struct mtx sc_mtx;
58 device_t sc_dev;
59 struct resource *mem_res;
60 struct callout tick_ch;
61 eventhandler_tag sc_wet;
62 void *intrhand;
63 u_int cmd;
64 u_int interval;
65 };
66
67 static inline uint32_t
RD4(struct wdt_softc * sc,bus_size_t off)68 RD4(struct wdt_softc *sc, bus_size_t off)
69 {
70
71 return (bus_read_4(sc->mem_res, off));
72 }
73
74 static inline void
WR4(struct wdt_softc * sc,bus_size_t off,uint32_t val)75 WR4(struct wdt_softc *sc, bus_size_t off, uint32_t val)
76 {
77
78 bus_write_4(sc->mem_res, off, val);
79 }
80
81 static int
wdt_intr(void * argp)82 wdt_intr(void *argp)
83 {
84 struct wdt_softc *sc = argp;
85
86
87 if (RD4(sc, WDT_SR) & (WDT_WDUNF | WDT_WDERR)) {
88 #if defined(KDB) && !defined(KDB_UNATTENDED)
89 kdb_backtrace();
90 kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout");
91 #else
92 panic("watchdog timeout");
93 #endif
94 }
95 return (FILTER_STRAY);
96 }
97
98 /* User interface, see watchdog(9) */
99 static void
wdt_watchdog(void * argp,u_int cmd,int * error)100 wdt_watchdog(void *argp, u_int cmd, int *error)
101 {
102 struct wdt_softc *sc = argp;
103 u_int interval;
104
105 mtx_lock(&sc->sc_mtx);
106
107 *error = 0;
108 sc->cmd = 0;
109 interval = cmd & WD_INTERVAL;
110 if (interval > WD_TO_16SEC)
111 *error = EOPNOTSUPP;
112 else if (interval > 0)
113 sc->cmd = interval | WD_ACTIVE;
114
115 /* We cannot turn off our watchdog so if user
116 * fails to turn us on go to passive mode. */
117 if ((sc->cmd & WD_ACTIVE) == 0)
118 sc->cmd = WD_PASSIVE;
119
120 mtx_unlock(&sc->sc_mtx);
121 }
122
123 /* This routine is called no matter what state the user sets the
124 * watchdog mode to. Called at a rate that is slightly less than
125 * half the hardware timeout. */
126 static void
wdt_tick(void * argp)127 wdt_tick(void *argp)
128 {
129 struct wdt_softc *sc = argp;
130
131 mtx_assert(&sc->sc_mtx, MA_OWNED);
132 if (sc->cmd & (WD_ACTIVE | WD_PASSIVE))
133 WR4(sc, WDT_CR, WDT_KEY|WDT_WDRSTT);
134
135 sc->cmd &= WD_PASSIVE;
136 callout_reset(&sc->tick_ch, sc->interval, wdt_tick, sc);
137 }
138
139 static int
wdt_probe(device_t dev)140 wdt_probe(device_t dev)
141 {
142 #ifdef FDT
143 if (!ofw_bus_is_compatible(dev, "atmel,at91sam9260-wdt"))
144 return (ENXIO);
145 #endif
146 device_set_desc(dev, "WDT");
147 return (0);
148 }
149
150 static int
wdt_attach(device_t dev)151 wdt_attach(device_t dev)
152 {
153 static struct wdt_softc *sc;
154 struct resource *irq;
155 uint32_t wdt_mr;
156 int rid, err;
157
158 sc = device_get_softc(dev);
159 sc->cmd = WD_PASSIVE;
160 sc->sc_dev = dev;
161
162 mtx_init(&sc->sc_mtx, device_get_nameunit(dev), "at91_wdt", MTX_DEF);
163 callout_init_mtx(&sc->tick_ch, &sc->sc_mtx, 0);
164
165 rid = 0;
166 sc->mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
167 RF_ACTIVE);
168
169 if (sc->mem_res == NULL)
170 panic("couldn't allocate wdt register resources");
171
172 wdt_mr = RD4(sc, WDT_MR);
173 if ((wdt_mr & WDT_WDRSTEN) == 0)
174 device_printf(dev, "Watchdog disabled! (Boot ROM?)\n");
175 else {
176 #ifdef WDT_RESET
177 /* Rude, full reset of whole system on watch dog timeout */
178 WR4(sc, WDT_MR, WDT_WDDBGHLT | WDT_WDD(0xC00)|
179 WDT_WDRSTEN| WDT_WDV(0xFFF));
180 #else
181 /* Generate stack trace and panic on watchdog timeout*/
182 WR4(sc, WDT_MR, WDT_WDDBGHLT | WDT_WDD(0xC00)|
183 WDT_WDFIEN| WDT_WDV(0xFFF));
184 #endif
185 /*
186 * This may have been set by Boot ROM so register value may
187 * not be what we just requested since this is a write once
188 * register.
189 */
190 wdt_mr = RD4(sc, WDT_MR);
191 if (wdt_mr & WDT_WDFIEN) {
192 rid = 0;
193 irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
194 RF_ACTIVE | RF_SHAREABLE);
195 if (!irq)
196 panic("could not allocate interrupt.\n");
197
198 err = bus_setup_intr(dev, irq, INTR_TYPE_CLK, wdt_intr,
199 NULL, sc, &sc->intrhand);
200 }
201
202 /* interval * hz */
203 sc->interval = (((wdt_mr & WDT_WDV(~0)) + 1) * WDT_DIV) /
204 (WDT_CLOCK/hz);
205
206 device_printf(dev, "watchdog timeout: %d seconds\n",
207 sc->interval / hz);
208
209 /* Slightly less than 1/2 of watchdog hardware timeout */
210 sc->interval = (sc->interval/2) - (sc->interval/20);
211 callout_reset(&sc->tick_ch, sc->interval, wdt_tick, sc);
212
213 /* Register us as a watchdog */
214 sc->sc_wet = EVENTHANDLER_REGISTER(watchdog_list,
215 wdt_watchdog, sc, 0);
216 }
217 return (0);
218 }
219
220 static device_method_t wdt_methods[] = {
221 DEVMETHOD(device_probe, wdt_probe),
222 DEVMETHOD(device_attach, wdt_attach),
223 DEVMETHOD_END
224 };
225
226 static driver_t wdt_driver = {
227 "at91_wdt",
228 wdt_methods,
229 sizeof(struct wdt_softc),
230 };
231
232 static devclass_t wdt_devclass;
233
234 #ifdef FDT
235 DRIVER_MODULE(at91_wdt, simplebus, wdt_driver, wdt_devclass, NULL, NULL);
236 #else
237 DRIVER_MODULE(at91_wdt, atmelarm, wdt_driver, wdt_devclass, NULL, NULL);
238 #endif
239