1 /* $NetBSD: wdog.c,v 1.13 2026/06/14 00:02:35 rkujawa Exp $ */ 2 3 /* 4 * Copyright (c) 2002 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Jason R. Thorpe and Simon Burge for Wasabi Systems, Inc. 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 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 /* 39 * Watchdog timer support for the IBM 405GP and 440/460EX processors. 40 */ 41 42 #include <sys/cdefs.h> 43 __KERNEL_RCSID(0, "$NetBSD: wdog.c,v 1.13 2026/06/14 00:02:35 rkujawa Exp $"); 44 45 #include <sys/param.h> 46 #include <sys/systm.h> 47 #include <sys/callout.h> 48 #include <sys/device.h> 49 #include <sys/cpu.h> 50 #include <sys/wdog.h> 51 52 #include <prop/proplib.h> 53 54 #include <powerpc/spr.h> 55 #include <powerpc/ibm4xx/spr.h> 56 #include <powerpc/ibm4xx/cpu.h> 57 #include <powerpc/ibm4xx/dev/opbvar.h> 58 59 #include <dev/sysmon/sysmonvar.h> 60 61 static int wdog_match(device_t, cfdata_t, void *); 62 static void wdog_attach(device_t, device_t, void *); 63 static int wdog_tickle(struct sysmon_wdog *); 64 static int wdog_setmode(struct sysmon_wdog *); 65 #ifdef PPC_IBM440 66 static void wdog_ktickle(void *); 67 #endif 68 69 struct wdog_softc { 70 device_t sc_dev; 71 struct sysmon_wdog sc_smw; 72 bool sc_wdog_armed; 73 int sc_wdog_period; 74 #ifdef PPC_IBM440 75 struct callout sc_tickler; /* self-tickle after "disarm" */ 76 #endif 77 }; 78 79 CFATTACH_DECL_NEW(wdog, sizeof(struct wdog_softc), 80 wdog_match, wdog_attach, NULL, NULL); 81 82 static int 83 wdog_match(device_t parent, cfdata_t cf, void *aux) 84 { 85 struct opb_attach_args * const oaa = aux; 86 87 /* match only watchdog devices */ 88 if (strcmp(oaa->opb_name, cf->cf_name) != 0) 89 return (0); 90 91 return (1); 92 } 93 94 static void 95 wdog_attach(device_t parent, device_t self, void *aux) 96 { 97 struct wdog_softc * const sc = device_private(self); 98 unsigned int processor_freq; 99 prop_number_t freq; 100 101 freq = prop_dictionary_get(board_properties, "processor-frequency"); 102 KASSERT(freq != NULL); 103 processor_freq = (unsigned int) prop_number_integer_value(freq); 104 105 #ifdef PPC_IBM440 106 /* 107 * The 440 watchdog period encodings sit four powers of two 108 * above the 405's... for whatever reason. 109 */ 110 sc->sc_wdog_period = (2LL << 33) / processor_freq; 111 #else 112 sc->sc_wdog_period = (2LL << 29) / processor_freq; 113 #endif 114 aprint_normal(": %d second period\n", sc->sc_wdog_period); 115 116 #ifdef PPC_IBM440 117 /* 118 * TSR[WRS] survives a watchdog-forced reset; report and clear 119 * it (TSR is write-1-to-clear) so a rebooted headless board 120 * leaves evidence of why. 121 * 122 * Btw. on Sam460ex firmware messes with TSR[WRS], so it's 123 * pointless. 124 */ 125 if (mfspr(SPR_TSR) & TSR_WRS_MASK) { 126 aprint_normal_dev(self, 127 "previous reset was forced by the watchdog\n"); 128 mtspr(SPR_TSR, TSR_WRS_MASK); 129 } 130 131 callout_init(&sc->sc_tickler, 0); 132 callout_setfunc(&sc->sc_tickler, wdog_ktickle, sc); 133 #endif 134 135 sc->sc_dev = self; 136 sc->sc_smw.smw_name = device_xname(self); 137 sc->sc_smw.smw_cookie = sc; 138 sc->sc_smw.smw_setmode = wdog_setmode; 139 sc->sc_smw.smw_tickle = wdog_tickle; 140 sc->sc_smw.smw_period = sc->sc_wdog_period; 141 142 if (sysmon_wdog_register(&sc->sc_smw) != 0) 143 aprint_error_dev(self, "unable to register with sysmon\n"); 144 } 145 146 static int 147 wdog_tickle(struct sysmon_wdog *smw) 148 { 149 #ifdef PPC_IBM440 150 /* 151 * TSR is write-1-to-clear 152 */ 153 mtspr(SPR_TSR, TSR_ENW | TSR_WIS); 154 #else 155 uint32_t tsr; 156 157 tsr = mfspr(SPR_TSR); 158 tsr |= TSR_ENW | TSR_WIS; 159 mtspr(SPR_TSR, tsr); 160 #endif 161 return (0); 162 } 163 164 #ifdef PPC_IBM440 165 /* 166 * TCR[WRC] is sticky: once the watchdog has been armed with a reset 167 * action it cannot be turned off until the next reset. "Disarming" 168 * therefore hands the tickling duty to this callout instead. 169 */ 170 static void 171 wdog_ktickle(void *arg) 172 { 173 struct wdog_softc * const sc = arg; 174 175 mtspr(SPR_TSR, TSR_ENW | TSR_WIS); 176 callout_schedule(&sc->sc_tickler, hz * sc->sc_wdog_period / 3); 177 } 178 #endif 179 180 static int 181 wdog_setmode(struct sysmon_wdog *smw) 182 { 183 struct wdog_softc * const sc = smw->smw_cookie; 184 185 if ((smw->smw_mode & WDOG_MODE_MASK) == WDOG_MODE_DISARMED) { 186 if (sc->sc_wdog_armed) { 187 #ifdef PPC_IBM440 188 /* 189 * The hardware cannot be disarmed (sticky 190 * TCR[WRC]); keep it fed from a callout so the 191 * system stays up without userland's help. 192 */ 193 sc->sc_wdog_armed = false; 194 wdog_ktickle(sc); 195 #else 196 uint32_t tsr = mfspr(SPR_TSR); 197 tsr &= ~(TSR_ENW | TSR_WIS); 198 mtspr(SPR_TSR, tsr); 199 sc->sc_wdog_armed = false; 200 #endif 201 } 202 } else { 203 if (smw->smw_period == WDOG_PERIOD_DEFAULT) 204 smw->smw_period = sc->sc_wdog_period; 205 else if (smw->smw_period != sc->sc_wdog_period) { 206 /* 207 * There's 4 set watchdog periods, but we only 208 * support the longest one (2.684 seconds on a 209 * 400MHz 405GP, 14.9 seconds on a 1.155GHz 210 * 460EX). 211 */ 212 return (EOPNOTSUPP); 213 } 214 sc->sc_wdog_armed = true; 215 216 #ifdef PPC_IBM440 217 /* 218 * TCR is shared with the clock (PIE/FIE) and the tprof 219 * FIT backend (FP), all read-modify-write: keep the 220 * update atomic with respect to them. 221 */ 222 const int s = splhigh(); 223 uint32_t tcr = mfspr(SPR_TCR); 224 tcr |= TCR_WP_2_33 | TCR_WRC_SYSTEM; 225 mtspr(SPR_TCR, tcr); 226 splx(s); 227 callout_stop(&sc->sc_tickler); 228 #else 229 uint32_t tcr = mfspr(SPR_TCR); 230 tcr |= TCR_WP_2_29 | TCR_WRC_SYSTEM; 231 mtspr(SPR_TCR, tcr); 232 #endif 233 234 /* Arm the watchdog. */ 235 wdog_tickle(smw); 236 } 237 return (0); 238 } 239
Indexes created Sun Oct 25 00:26:45 UTC 2026