2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2012, 2013 The FreeBSD Foundation
7 * This software was developed by Oleksandr Rybalko under sponsorship
8 * from the FreeBSD Foundation.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
37 #include <sys/eventhandler.h>
38 #include <sys/kernel.h>
40 #include <sys/module.h>
41 #include <sys/mutex.h>
42 #include <sys/resource.h>
44 #include <sys/systm.h>
46 #include <sys/watchdog.h>
48 #include <machine/bus.h>
49 #include <machine/intr.h>
51 #include <dev/ofw/openfirm.h>
52 #include <dev/ofw/ofw_bus.h>
53 #include <dev/ofw/ofw_bus_subr.h>
55 #include <arm/freescale/imx/imx_machdep.h>
56 #include <arm/freescale/imx/imx_wdogreg.h>
58 struct imx_wdog_softc {
61 struct resource *sc_res[2];
67 static struct resource_spec imx_wdog_spec[] = {
68 { SYS_RES_MEMORY, 0, RF_ACTIVE },
69 { SYS_RES_IRQ, 0, RF_ACTIVE },
76 static struct ofw_compat_data compat_data[] = {
77 {"fsl,imx6sx-wdt", 1},
78 {"fsl,imx6sl-wdt", 1},
90 static inline uint16_t
91 RD2(struct imx_wdog_softc *sc, bus_size_t offs)
94 return (bus_read_2(sc->sc_res[MEMRES], offs));
98 WR2(struct imx_wdog_softc *sc, bus_size_t offs, uint16_t val)
101 bus_write_2(sc->sc_res[MEMRES], offs, val);
105 imx_wdog_enable(struct imx_wdog_softc *sc, u_int timeout)
109 if (timeout < 1 || timeout > 128)
112 mtx_lock(&sc->sc_mtx);
113 if (timeout != sc->sc_timeout) {
114 sc->sc_timeout = timeout;
115 reg = RD2(sc, WDOG_CR_REG);
116 reg &= ~WDOG_CR_WT_MASK;
117 reg |= ((2 * timeout - 1) << WDOG_CR_WT_SHIFT);
118 WR2(sc, WDOG_CR_REG, reg | WDOG_CR_WDE);
120 /* Refresh counter */
121 WR2(sc, WDOG_SR_REG, WDOG_SR_STEP1);
122 WR2(sc, WDOG_SR_REG, WDOG_SR_STEP2);
123 /* Watchdog active, can disable rom-boot watchdog. */
124 if (sc->sc_pde_enabled) {
125 sc->sc_pde_enabled = false;
126 reg = RD2(sc, WDOG_MCR_REG);
127 WR2(sc, WDOG_MCR_REG, reg & ~WDOG_MCR_PDE);
129 mtx_unlock(&sc->sc_mtx);
135 imx_watchdog(void *arg, u_int cmd, int *error)
137 struct imx_wdog_softc *sc;
143 device_printf(sc->sc_dev, "Can not be disabled.\n");
146 timeout = (u_int)((1ULL << (cmd & WD_INTERVAL)) / 1000000000U);
147 if (imx_wdog_enable(sc, timeout) == 0)
153 imx_wdog_intr(void *arg)
155 struct imx_wdog_softc *sc = arg;
158 * When configured for external reset, the actual reset is supposed to
159 * happen when some external device responds to the assertion of the
160 * WDOG_B signal by asserting the POR signal to the chip. This
161 * interrupt handler is a backstop mechanism; it is set up to fire
162 * simultaneously with WDOG_B, and if the external reset happens we'll
163 * never actually make it to here. If we do make it here, just trigger
164 * a software reset. That code will see that external reset is
165 * configured, and it will wait for 1 second for it to take effect, then
166 * it will do a software reset as a fallback.
168 imx_wdog_cpu_reset(BUS_SPACE_PHYSADDR(sc->sc_res[MEMRES], WDOG_CR_REG));
170 return (FILTER_HANDLED); /* unreached */
174 imx_wdog_probe(device_t dev)
177 if (!ofw_bus_status_okay(dev))
180 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
183 device_set_desc(dev, "Freescale i.MX Watchdog");
188 imx_wdog_attach(device_t dev)
190 struct imx_wdog_softc *sc;
193 sc = device_get_softc(dev);
196 if (bus_alloc_resources(dev, imx_wdog_spec, sc->sc_res)) {
197 device_printf(dev, "could not allocate resources\n");
201 mtx_init(&sc->sc_mtx, device_get_nameunit(dev), "imx_wdt", MTX_DEF);
204 * If we're configured to assert an external reset signal, set up the
205 * hardware to do so, and install an interrupt handler whose only
206 * purpose is to backstop the external reset. Don't worry if the
207 * interrupt setup fails, since it's only a backstop measure.
209 if (ofw_bus_has_prop(sc->sc_dev, "fsl,ext-reset-output")) {
210 WR2(sc, WDOG_CR_REG, WDOG_CR_WDT | RD2(sc, WDOG_CR_REG));
211 bus_setup_intr(sc->sc_dev, sc->sc_res[IRQRES],
212 INTR_TYPE_MISC | INTR_MPSAFE, imx_wdog_intr, NULL, sc,
214 WR2(sc, WDOG_ICR_REG, WDOG_ICR_WIE); /* Enable, count is 0. */
218 * Note whether the rom-boot so-called "power-down" watchdog is active,
219 * so we can disable it when the regular watchdog is first enabled.
221 if (RD2(sc, WDOG_MCR_REG) & WDOG_MCR_PDE)
222 sc->sc_pde_enabled = true;
224 EVENTHANDLER_REGISTER(watchdog_list, imx_watchdog, sc, 0);
226 /* If there is a timeout-sec property, activate the watchdog. */
227 if (OF_getencprop(ofw_bus_get_node(sc->sc_dev), "timeout-sec",
228 &timeout, sizeof(timeout)) == sizeof(timeout)) {
229 if (timeout < 1 || timeout > 128) {
230 device_printf(sc->sc_dev, "ERROR: bad timeout-sec "
231 "property value %u, using 128\n", timeout);
234 imx_wdog_enable(sc, timeout);
235 device_printf(sc->sc_dev, "watchdog enabled using "
236 "timeout-sec property value %u\n", timeout);
240 * The watchdog hardware cannot be disabled, so there's little point in
241 * coding up a detach() routine to carefully tear everything down, just
242 * make the device busy so that detach can't happen.
244 device_busy(sc->sc_dev);
248 static device_method_t imx_wdog_methods[] = {
249 DEVMETHOD(device_probe, imx_wdog_probe),
250 DEVMETHOD(device_attach, imx_wdog_attach),
254 static driver_t imx_wdog_driver = {
257 sizeof(struct imx_wdog_softc),
260 static devclass_t imx_wdog_devclass;
262 EARLY_DRIVER_MODULE(imx_wdog, simplebus, imx_wdog_driver,
263 imx_wdog_devclass, 0, 0, BUS_PASS_TIMER);
264 SIMPLEBUS_PNP_INFO(compat_data);