xref: /freebsd/sys/dev/itwd/itwd.c (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2019 Andriy Gapon
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/bus.h>
34 #include <sys/eventhandler.h>
35 #include <sys/module.h>
36 #include <sys/rman.h>
37 #include <sys/systm.h>
38 #include <sys/watchdog.h>
39 
40 #include <dev/superio/superio.h>
41 
42 #include <machine/bus.h>
43 #include <machine/resource.h>
44 
45 
46 struct itwd_softc {
47 	eventhandler_tag	wd_ev;
48 	void			*intr_handle;
49 	struct resource		*intr_res;
50 	int			intr_rid;
51 };
52 
53 static void
54 wd_func(void *priv, u_int cmd, int *error)
55 {
56 	device_t dev = priv;
57 	uint64_t timeout;
58 	uint8_t val;
59 
60 
61 	if (cmd != 0) {
62 		cmd &= WD_INTERVAL;
63 
64 		/*
65 		 * Convert the requested timeout to seconds.
66 		 * If the timeout is smaller than the minimal supported value
67 		 * then set it to the minimum.
68 		 * TODO This hardware actually supports 64ms resolution
69 		 * when bit 5 of 0x72 is set.  Switch to that resolution when
70 		 * needed.
71 		 */
72 		if (cmd >= WD_TO_1SEC)
73 			timeout = (uint64_t)1 << (cmd - WD_TO_1SEC);
74 		else
75 			timeout = 1;
76 
77 		/* TODO If timeout is greater than maximum value
78 		 * that can be specified in seconds, we should
79 		 * switch the timer to minutes mode by clearing
80 		 * bit 7 of 0x72 (ensure that bit 5 is also cleared).
81 		 *
82 		 * For now, just disable the timer to honor the
83 		 * watchdog(9) protocol.
84 		 *
85 		 * XXX The timeout actually can be up to 65535 units
86 		 * as it is set via two registers 0x73, LSB, and 0x74,
87 		 * MSB.  But it is not clear what the protocol for writing
88 		 * those two registers is.
89 		 */
90 		if (timeout <= UINT8_MAX) {
91 			val = timeout;
92 			*error = 0;
93 		} else {
94 			/* error left unchanged */
95 			val = 0;
96 		}
97 	} else {
98 		val = 0;
99 	}
100 #ifdef DIAGNOSTIC
101 	if (bootverbose)
102 		device_printf(dev, "setting timeout to %d\n", val);
103 #endif
104 	superio_write(dev, 0x73, val);
105 	if (superio_read(dev, 0x73) != val)
106 		superio_write(dev, 0x73, val);
107 }
108 
109 static void
110 itwd_intr(void *cookie)
111 {
112 	device_t dev = cookie;
113 	uint8_t val;
114 
115 	val = superio_read(dev, 0x71);
116 	if (bootverbose)
117 		device_printf(dev, "got interrupt, wdt status = %d\n", val & 1);
118 	superio_write(dev, 0x71, val & ~((uint8_t)0x01));
119 }
120 
121 static int
122 itwd_probe(device_t dev)
123 {
124 
125 	if (superio_vendor(dev) != SUPERIO_VENDOR_ITE)
126 		return (ENXIO);
127 	if (superio_get_type(dev) != SUPERIO_DEV_WDT)
128 		return (ENXIO);
129 	device_set_desc(dev, "Watchdog Timer on ITE SuperIO");
130 	return (BUS_PROBE_DEFAULT);
131 }
132 
133 static int
134 itwd_attach(device_t dev)
135 {
136 	struct itwd_softc *sc = device_get_softc(dev);
137 	int irq = 0;
138 	int nmi = 0;
139 	int error;
140 
141 	/* First, reset the timeout, just in case. */
142 	superio_write(dev, 0x74, 0);
143 	superio_write(dev, 0x73, 0);
144 
145 	TUNABLE_INT_FETCH("dev.itwd.irq", &irq);
146 	TUNABLE_INT_FETCH("dev.itwd.nmi", &nmi);
147 	if (irq < 0 || irq > 15) {
148 		device_printf(dev, "Ignoring invalid IRQ value %d\n", irq);
149 		irq = 0;
150 	}
151 	if (irq == 0 && nmi) {
152 		device_printf(dev, "Ignoring NMI mode if IRQ is not set\n");
153 		nmi = 0;
154 	}
155 
156 	/*
157 	 * NB: if the interrupt has been configured for the NMI delivery,
158 	 * then it is not available for the regular interrupt allocation.
159 	 * Thus, we configure the hardware to generate the interrupt,
160 	 * but do not attempt to allocate and setup it as a regular
161 	 * interrupt.
162 	 */
163 	if (irq != 0 && !nmi) {
164 		sc->intr_rid = 0;
165 		bus_set_resource(dev, SYS_RES_IRQ, sc->intr_rid, irq, 1);
166 
167 		sc->intr_res = bus_alloc_resource_any(dev, SYS_RES_IRQ,
168 		    &sc->intr_rid, RF_ACTIVE);
169 		if (sc->intr_res == NULL) {
170 			device_printf(dev, "unable to map interrupt\n");
171 			return (ENXIO);
172 		}
173 		error = bus_setup_intr(dev, sc->intr_res,
174 		    INTR_TYPE_MISC | INTR_MPSAFE, NULL, itwd_intr, dev,
175 		    &sc->intr_handle);
176 		if (error != 0) {
177 			bus_release_resource(dev, SYS_RES_IRQ,
178 			    sc->intr_rid, sc->intr_res);
179 			device_printf(dev, "Unable to setup irq: error %d\n",
180 			    error);
181 			return (ENXIO);
182 		}
183 	}
184 	if (irq != 0) {
185 		device_printf(dev, "Using IRQ%d to signal timeout\n", irq);
186 	} else {
187 		/* System reset via KBRST. */
188 		irq = 0x40;
189 		device_printf(dev, "Configured for system reset on timeout\n");
190 	}
191 
192 	superio_write(dev, 0x71, 0);
193 	superio_write(dev, 0x72, 0x80 | (uint8_t)irq);
194 
195 	sc->wd_ev = EVENTHANDLER_REGISTER(watchdog_list, wd_func, dev, 0);
196 	return (0);
197 }
198 
199 static int
200 itwd_detach(device_t dev)
201 {
202 	struct itwd_softc *sc = device_get_softc(dev);
203 	int dummy;
204 
205 	if (sc->wd_ev != NULL)
206 		EVENTHANDLER_DEREGISTER(watchdog_list, sc->wd_ev);
207 	wd_func(dev, 0, &dummy);
208 	if (sc->intr_handle)
209 		bus_teardown_intr(dev, sc->intr_res, sc->intr_handle);
210 	if (sc->intr_res)
211 		bus_release_resource(dev, SYS_RES_IRQ, sc->intr_rid,
212 		    sc->intr_res);
213 	return (0);
214 }
215 
216 static device_method_t itwd_methods[] = {
217 	/* Methods from the device interface */
218 	DEVMETHOD(device_probe,		itwd_probe),
219 	DEVMETHOD(device_attach,	itwd_attach),
220 	DEVMETHOD(device_detach,	itwd_detach),
221 
222 	/* Terminate method list */
223 	{ 0, 0 }
224 };
225 
226 static driver_t itwd_driver = {
227 	"itwd",
228 	itwd_methods,
229 	sizeof (struct itwd_softc)
230 };
231 
232 static devclass_t itwd_devclass;
233 
234 DRIVER_MODULE(itwd, superio, itwd_driver, itwd_devclass, NULL, NULL);
235 MODULE_DEPEND(itwd, superio, 1, 1, 1);
236 MODULE_VERSION(itwd, 1);
237