1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2012, 2013 The FreeBSD Foundation 5 * 6 * This software was developed by Oleksandr Rybalko under sponsorship 7 * from the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/param.h> 35 #include <sys/bus.h> 36 #include <sys/eventhandler.h> 37 #include <sys/kernel.h> 38 #include <sys/lock.h> 39 #include <sys/module.h> 40 #include <sys/mutex.h> 41 #include <sys/resource.h> 42 #include <sys/rman.h> 43 #include <sys/systm.h> 44 #include <sys/time.h> 45 #include <sys/watchdog.h> 46 47 #include <machine/bus.h> 48 #include <machine/intr.h> 49 50 #include <dev/ofw/openfirm.h> 51 #include <dev/ofw/ofw_bus.h> 52 #include <dev/ofw/ofw_bus_subr.h> 53 54 #include <arm/freescale/imx/imx_machdep.h> 55 #include <arm/freescale/imx/imx_wdogreg.h> 56 57 struct imx_wdog_softc { 58 struct mtx sc_mtx; 59 device_t sc_dev; 60 struct resource *sc_res[2]; 61 void *sc_ih; 62 uint32_t sc_timeout; 63 bool sc_pde_enabled; 64 }; 65 66 static struct resource_spec imx_wdog_spec[] = { 67 { SYS_RES_MEMORY, 0, RF_ACTIVE }, 68 { SYS_RES_IRQ, 0, RF_ACTIVE }, 69 RESOURCE_SPEC_END 70 }; 71 72 #define MEMRES 0 73 #define IRQRES 1 74 75 static struct ofw_compat_data compat_data[] = { 76 {"fsl,imx6sx-wdt", 1}, 77 {"fsl,imx6sl-wdt", 1}, 78 {"fsl,imx6q-wdt", 1}, 79 {"fsl,imx53-wdt", 1}, 80 {"fsl,imx51-wdt", 1}, 81 {"fsl,imx50-wdt", 1}, 82 {"fsl,imx35-wdt", 1}, 83 {"fsl,imx27-wdt", 1}, 84 {"fsl,imx25-wdt", 1}, 85 {"fsl,imx21-wdt", 1}, 86 {NULL, 0} 87 }; 88 89 static inline uint16_t 90 RD2(struct imx_wdog_softc *sc, bus_size_t offs) 91 { 92 93 return (bus_read_2(sc->sc_res[MEMRES], offs)); 94 } 95 96 static inline void 97 WR2(struct imx_wdog_softc *sc, bus_size_t offs, uint16_t val) 98 { 99 100 bus_write_2(sc->sc_res[MEMRES], offs, val); 101 } 102 103 static int 104 imx_wdog_enable(struct imx_wdog_softc *sc, u_int timeout) 105 { 106 uint16_t reg; 107 108 if (timeout < 1 || timeout > 128) 109 return (EINVAL); 110 111 mtx_lock(&sc->sc_mtx); 112 if (timeout != sc->sc_timeout) { 113 sc->sc_timeout = timeout; 114 reg = RD2(sc, WDOG_CR_REG); 115 reg &= ~WDOG_CR_WT_MASK; 116 reg |= ((2 * timeout - 1) << WDOG_CR_WT_SHIFT); 117 WR2(sc, WDOG_CR_REG, reg | WDOG_CR_WDE); 118 } 119 /* Refresh counter */ 120 WR2(sc, WDOG_SR_REG, WDOG_SR_STEP1); 121 WR2(sc, WDOG_SR_REG, WDOG_SR_STEP2); 122 /* Watchdog active, can disable rom-boot watchdog. */ 123 if (sc->sc_pde_enabled) { 124 sc->sc_pde_enabled = false; 125 reg = RD2(sc, WDOG_MCR_REG); 126 WR2(sc, WDOG_MCR_REG, reg & ~WDOG_MCR_PDE); 127 } 128 mtx_unlock(&sc->sc_mtx); 129 130 return (0); 131 } 132 133 static void 134 imx_watchdog(void *arg, u_int cmd, int *error) 135 { 136 struct imx_wdog_softc *sc; 137 u_int timeout; 138 139 sc = arg; 140 if (cmd == 0) { 141 if (bootverbose) 142 device_printf(sc->sc_dev, "Can not be disabled.\n"); 143 *error = EOPNOTSUPP; 144 } else { 145 timeout = (u_int)((1ULL << (cmd & WD_INTERVAL)) / 1000000000U); 146 if (imx_wdog_enable(sc, timeout) == 0) 147 *error = 0; 148 } 149 } 150 151 static int 152 imx_wdog_intr(void *arg) 153 { 154 struct imx_wdog_softc *sc = arg; 155 156 /* 157 * When configured for external reset, the actual reset is supposed to 158 * happen when some external device responds to the assertion of the 159 * WDOG_B signal by asserting the POR signal to the chip. This 160 * interrupt handler is a backstop mechanism; it is set up to fire 161 * simultaneously with WDOG_B, and if the external reset happens we'll 162 * never actually make it to here. If we do make it here, just trigger 163 * a software reset. That code will see that external reset is 164 * configured, and it will wait for 1 second for it to take effect, then 165 * it will do a software reset as a fallback. 166 */ 167 imx_wdog_cpu_reset(BUS_SPACE_PHYSADDR(sc->sc_res[MEMRES], WDOG_CR_REG)); 168 169 return (FILTER_HANDLED); /* unreached */ 170 } 171 172 static int 173 imx_wdog_probe(device_t dev) 174 { 175 176 if (!ofw_bus_status_okay(dev)) 177 return (ENXIO); 178 179 if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0) 180 return (ENXIO); 181 182 device_set_desc(dev, "Freescale i.MX Watchdog"); 183 return (0); 184 } 185 186 static int 187 imx_wdog_attach(device_t dev) 188 { 189 struct imx_wdog_softc *sc; 190 pcell_t timeout; 191 192 sc = device_get_softc(dev); 193 sc->sc_dev = dev; 194 195 if (bus_alloc_resources(dev, imx_wdog_spec, sc->sc_res)) { 196 device_printf(dev, "could not allocate resources\n"); 197 return (ENXIO); 198 } 199 200 mtx_init(&sc->sc_mtx, device_get_nameunit(dev), "imx_wdt", MTX_DEF); 201 202 /* 203 * If we're configured to assert an external reset signal, set up the 204 * hardware to do so, and install an interrupt handler whose only 205 * purpose is to backstop the external reset. Don't worry if the 206 * interrupt setup fails, since it's only a backstop measure. 207 */ 208 if (ofw_bus_has_prop(sc->sc_dev, "fsl,ext-reset-output")) { 209 WR2(sc, WDOG_CR_REG, WDOG_CR_WDT | RD2(sc, WDOG_CR_REG)); 210 bus_setup_intr(sc->sc_dev, sc->sc_res[IRQRES], 211 INTR_TYPE_MISC | INTR_MPSAFE, imx_wdog_intr, NULL, sc, 212 &sc->sc_ih); 213 WR2(sc, WDOG_ICR_REG, WDOG_ICR_WIE); /* Enable, count is 0. */ 214 } 215 216 /* 217 * Note whether the rom-boot so-called "power-down" watchdog is active, 218 * so we can disable it when the regular watchdog is first enabled. 219 */ 220 if (RD2(sc, WDOG_MCR_REG) & WDOG_MCR_PDE) 221 sc->sc_pde_enabled = true; 222 223 EVENTHANDLER_REGISTER(watchdog_list, imx_watchdog, sc, 0); 224 225 /* If there is a timeout-sec property, activate the watchdog. */ 226 if (OF_getencprop(ofw_bus_get_node(sc->sc_dev), "timeout-sec", 227 &timeout, sizeof(timeout)) == sizeof(timeout)) { 228 if (timeout < 1 || timeout > 128) { 229 device_printf(sc->sc_dev, "ERROR: bad timeout-sec " 230 "property value %u, using 128\n", timeout); 231 timeout = 128; 232 } 233 imx_wdog_enable(sc, timeout); 234 device_printf(sc->sc_dev, "watchdog enabled using " 235 "timeout-sec property value %u\n", timeout); 236 } 237 238 /* 239 * The watchdog hardware cannot be disabled, so there's little point in 240 * coding up a detach() routine to carefully tear everything down, just 241 * make the device busy so that detach can't happen. 242 */ 243 device_busy(sc->sc_dev); 244 return (0); 245 } 246 247 static device_method_t imx_wdog_methods[] = { 248 DEVMETHOD(device_probe, imx_wdog_probe), 249 DEVMETHOD(device_attach, imx_wdog_attach), 250 DEVMETHOD_END 251 }; 252 253 static driver_t imx_wdog_driver = { 254 "imx_wdog", 255 imx_wdog_methods, 256 sizeof(struct imx_wdog_softc), 257 }; 258 259 EARLY_DRIVER_MODULE(imx_wdog, simplebus, imx_wdog_driver, 0, 0, BUS_PASS_TIMER); 260 SIMPLEBUS_PNP_INFO(compat_data); 261