xref: /freebsd/sys/dev/viawd/viawd.c (revision cddbc3b40812213ff00041f79174cac0be360a2a)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2011 Fabien Thomas <fabient@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/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/module.h>
35 #include <sys/systm.h>
36 #include <sys/bus.h>
37 #include <machine/bus.h>
38 #include <sys/rman.h>
39 #include <machine/resource.h>
40 #include <sys/watchdog.h>
41 
42 #include <isa/isavar.h>
43 #include <dev/pci/pcivar.h>
44 
45 #include "viawd.h"
46 
47 #define	viawd_read_4(sc, off)	bus_read_4((sc)->wd_res, (off))
48 #define	viawd_write_4(sc, off, val)	\
49 	bus_write_4((sc)->wd_res, (off), (val))
50 
51 static struct viawd_device viawd_devices[] = {
52 	{ DEVICEID_VT8251, "VIA VT8251 watchdog timer" },
53 	{ DEVICEID_CX700,  "VIA CX700 watchdog timer" },
54 	{ DEVICEID_VX800,  "VIA VX800 watchdog timer" },
55 	{ DEVICEID_VX855,  "VIA VX855 watchdog timer" },
56 	{ DEVICEID_VX900,  "VIA VX900 watchdog timer" },
57 	{ 0, NULL },
58 };
59 
60 static devclass_t viawd_devclass;
61 
62 static void
63 viawd_tmr_state(struct viawd_softc *sc, int enable)
64 {
65 	uint32_t reg;
66 
67 	reg = viawd_read_4(sc, VIAWD_MEM_CTRL);
68 	if (enable)
69 		reg |= VIAWD_MEM_CTRL_TRIGGER | VIAWD_MEM_CTRL_ENABLE;
70 	else
71 		reg &= ~VIAWD_MEM_CTRL_ENABLE;
72 	viawd_write_4(sc, VIAWD_MEM_CTRL, reg);
73 }
74 
75 static void
76 viawd_tmr_set(struct viawd_softc *sc, unsigned int timeout)
77 {
78 
79 	/* Keep value in range. */
80 	if (timeout < VIAWD_MEM_COUNT_MIN)
81 		timeout = VIAWD_MEM_COUNT_MIN;
82 	else if (timeout > VIAWD_MEM_COUNT_MAX)
83 		timeout = VIAWD_MEM_COUNT_MAX;
84 
85 	viawd_write_4(sc, VIAWD_MEM_COUNT, timeout);
86 	sc->timeout = timeout;
87 }
88 
89 /*
90  * Watchdog event handler - called by the framework to enable or disable
91  * the watchdog or change the initial timeout value.
92  */
93 static void
94 viawd_event(void *arg, unsigned int cmd, int *error)
95 {
96 	struct viawd_softc *sc = arg;
97 	unsigned int timeout;
98 
99 	/* Convert from power-of-two-ns to second. */
100 	cmd &= WD_INTERVAL;
101 	timeout = ((uint64_t)1 << cmd) / 1000000000;
102 	if (cmd) {
103 		if (timeout != sc->timeout)
104 			viawd_tmr_set(sc, timeout);
105 		viawd_tmr_state(sc, 1);
106 		*error = 0;
107 	} else
108 		viawd_tmr_state(sc, 0);
109 }
110 
111 /* Look for a supported VIA south bridge. */
112 static struct viawd_device *
113 viawd_find(device_t dev)
114 {
115 	struct viawd_device *id;
116 
117 	if (pci_get_vendor(dev) != VENDORID_VIA)
118 		return (NULL);
119 	for (id = viawd_devices; id->desc != NULL; id++)
120 		if (pci_get_device(dev) == id->device)
121 			return (id);
122 	return (NULL);
123 }
124 
125 static void
126 viawd_identify(driver_t *driver, device_t parent)
127 {
128 
129 	if (viawd_find(parent) == NULL)
130 		return;
131 
132 	if (device_find_child(parent, driver->name, -1) == NULL)
133 		BUS_ADD_CHILD(parent, 0, driver->name, 0);
134 }
135 
136 static int
137 viawd_probe(device_t dev)
138 {
139 	struct viawd_device *id;
140 
141 	id = viawd_find(device_get_parent(dev));
142 	KASSERT(id != NULL, ("parent should be a valid VIA SB"));
143 	device_set_desc(dev, id->desc);
144 	return (BUS_PROBE_GENERIC);
145 }
146 
147 static int
148 viawd_attach(device_t dev)
149 {
150 	device_t sb_dev;
151 	struct viawd_softc *sc;
152 	uint32_t pmbase, reg;
153 
154 	sc = device_get_softc(dev);
155 	sc->dev = dev;
156 
157 	sb_dev = device_get_parent(dev);
158 	if (sb_dev == NULL) {
159 		device_printf(dev, "Can not find watchdog device.\n");
160 		goto fail;
161 	}
162 	sc->sb_dev = sb_dev;
163 
164 	/* Get watchdog memory base. */
165 	pmbase = pci_read_config(sb_dev, VIAWD_CONFIG_BASE, 4);
166 	if (pmbase == 0) {
167 		device_printf(dev,
168 		    "Watchdog disabled in BIOS or hardware\n");
169 		goto fail;
170 	}
171 
172 	/* Allocate I/O register space. */
173 	sc->wd_rid = VIAWD_CONFIG_BASE;
174 	sc->wd_res = bus_alloc_resource_any(sb_dev, SYS_RES_MEMORY, &sc->wd_rid,
175 	    RF_ACTIVE | RF_SHAREABLE);
176 	if (sc->wd_res == NULL) {
177 		device_printf(dev, "Unable to map watchdog memory\n");
178 		goto fail;
179 	}
180 	if (rman_get_size(sc->wd_res) < VIAWD_MEM_LEN) {
181 		device_printf(dev, "Bad size for watchdog memory: %#x\n",
182 		    (unsigned)rman_get_size(sc->wd_res));
183 		goto fail;
184 	}
185 
186 	/* Check if watchdog fired last boot. */
187 	reg = viawd_read_4(sc, VIAWD_MEM_CTRL);
188 	if (reg & VIAWD_MEM_CTRL_FIRED) {
189 		device_printf(dev,
190 		    "ERROR: watchdog rebooted the system\n");
191 		/* Reset bit state. */
192 		viawd_write_4(sc, VIAWD_MEM_CTRL, reg);
193 	}
194 
195 	/* Register the watchdog event handler. */
196 	sc->ev_tag = EVENTHANDLER_REGISTER(watchdog_list, viawd_event, sc, 0);
197 
198 	return (0);
199 fail:
200 	if (sc->wd_res != NULL)
201 		bus_release_resource(sb_dev, SYS_RES_MEMORY,
202 		    sc->wd_rid, sc->wd_res);
203 	return (ENXIO);
204 }
205 
206 static int
207 viawd_detach(device_t dev)
208 {
209 	struct viawd_softc *sc;
210 	uint32_t reg;
211 
212 	sc = device_get_softc(dev);
213 
214 	/* Deregister event handler. */
215 	if (sc->ev_tag != NULL)
216 		EVENTHANDLER_DEREGISTER(watchdog_list, sc->ev_tag);
217 	sc->ev_tag = NULL;
218 
219 	/*
220 	 * Do not stop the watchdog on shutdown if active but bump the
221 	 * timer to avoid spurious reset.
222 	 */
223 	reg = viawd_read_4(sc, VIAWD_MEM_CTRL);
224 	if (reg & VIAWD_MEM_CTRL_ENABLE) {
225 		viawd_tmr_set(sc, VIAWD_TIMEOUT_SHUTDOWN);
226 		viawd_tmr_state(sc, 1);
227 		device_printf(dev,
228 		    "Keeping watchog alive during shutdown for %d seconds\n",
229 		    VIAWD_TIMEOUT_SHUTDOWN);
230 	}
231 
232 	if (sc->wd_res != NULL)
233 		bus_release_resource(sc->sb_dev, SYS_RES_MEMORY,
234 		    sc->wd_rid, sc->wd_res);
235 
236 	return (0);
237 }
238 
239 static device_method_t viawd_methods[] = {
240 	DEVMETHOD(device_identify, viawd_identify),
241 	DEVMETHOD(device_probe,	viawd_probe),
242 	DEVMETHOD(device_attach, viawd_attach),
243 	DEVMETHOD(device_detach, viawd_detach),
244 	DEVMETHOD(device_shutdown, viawd_detach),
245 	{0,0}
246 };
247 
248 static driver_t viawd_driver = {
249 	"viawd",
250 	viawd_methods,
251 	sizeof(struct viawd_softc),
252 };
253 
254 DRIVER_MODULE(viawd, isab, viawd_driver, viawd_devclass, NULL, NULL);
255