1 /*- 2 * Copyright (c) 2014 Rui Paulo <rpaulo@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 17 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 18 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 20 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 22 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 23 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 24 * POSSIBILITY OF SUCH DAMAGE. 25 */ 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/bus.h> 32 #include <sys/conf.h> 33 #include <sys/eventhandler.h> 34 #include <sys/kernel.h> 35 #include <sys/module.h> 36 #include <sys/malloc.h> 37 #include <sys/rman.h> 38 #include <sys/event.h> 39 #include <sys/selinfo.h> 40 #include <sys/watchdog.h> 41 #include <machine/bus.h> 42 #include <machine/cpu.h> 43 #include <machine/frame.h> 44 #include <machine/intr.h> 45 46 #include <dev/ofw/openfirm.h> 47 #include <dev/ofw/ofw_bus.h> 48 #include <dev/ofw/ofw_bus_subr.h> 49 50 #include <machine/bus.h> 51 52 #include <arm/ti/ti_wdt.h> 53 54 #ifdef DEBUG 55 #define DPRINTF(fmt, ...) do { \ 56 printf("%s: ", __func__); \ 57 printf(fmt, __VA_ARGS__); \ 58 } while (0) 59 #else 60 #define DPRINTF(fmt, ...) 61 #endif 62 63 static device_probe_t ti_wdt_probe; 64 static device_attach_t ti_wdt_attach; 65 static device_detach_t ti_wdt_detach; 66 static void ti_wdt_intr(void *); 67 static void ti_wdt_event(void *, unsigned int, int *); 68 69 struct ti_wdt_softc { 70 struct resource *sc_mem_res; 71 struct resource *sc_irq_res; 72 void *sc_intr; 73 bus_space_tag_t sc_bt; 74 bus_space_handle_t sc_bh; 75 eventhandler_tag sc_ev_tag; 76 }; 77 78 static device_method_t ti_wdt_methods[] = { 79 DEVMETHOD(device_probe, ti_wdt_probe), 80 DEVMETHOD(device_attach, ti_wdt_attach), 81 DEVMETHOD(device_detach, ti_wdt_detach), 82 83 DEVMETHOD_END 84 }; 85 86 static driver_t ti_wdt_driver = { 87 "ti_wdt", 88 ti_wdt_methods, 89 sizeof(struct ti_wdt_softc) 90 }; 91 92 static devclass_t ti_wdt_devclass; 93 94 DRIVER_MODULE(ti_wdt, simplebus, ti_wdt_driver, ti_wdt_devclass, 0, 0); 95 MODULE_DEPEND(ti_wdt, ti_sysc, 1, 1, 1); 96 97 static __inline uint32_t 98 ti_wdt_reg_read(struct ti_wdt_softc *sc, uint32_t reg) 99 { 100 101 return (bus_space_read_4(sc->sc_bt, sc->sc_bh, reg)); 102 } 103 104 static __inline void 105 ti_wdt_reg_write(struct ti_wdt_softc *sc, uint32_t reg, uint32_t val) 106 { 107 108 bus_space_write_4(sc->sc_bt, sc->sc_bh, reg, val); 109 } 110 111 /* 112 * Wait for the write to a specific synchronised register to complete. 113 */ 114 static __inline void 115 ti_wdt_reg_wait(struct ti_wdt_softc *sc, uint32_t bit) 116 { 117 118 while (ti_wdt_reg_read(sc, TI_WDT_WWPS) & bit) 119 DELAY(10); 120 } 121 122 static __inline void 123 ti_wdt_disable(struct ti_wdt_softc *sc) 124 { 125 126 DPRINTF("disabling watchdog %p\n", sc); 127 ti_wdt_reg_write(sc, TI_WDT_WSPR, 0xAAAA); 128 ti_wdt_reg_wait(sc, TI_W_PEND_WSPR); 129 ti_wdt_reg_write(sc, TI_WDT_WSPR, 0x5555); 130 ti_wdt_reg_wait(sc, TI_W_PEND_WSPR); 131 } 132 133 static __inline void 134 ti_wdt_enable(struct ti_wdt_softc *sc) 135 { 136 137 DPRINTF("enabling watchdog %p\n", sc); 138 ti_wdt_reg_write(sc, TI_WDT_WSPR, 0xBBBB); 139 ti_wdt_reg_wait(sc, TI_W_PEND_WSPR); 140 ti_wdt_reg_write(sc, TI_WDT_WSPR, 0x4444); 141 ti_wdt_reg_wait(sc, TI_W_PEND_WSPR); 142 } 143 144 static int 145 ti_wdt_probe(device_t dev) 146 { 147 148 if (!ofw_bus_status_okay(dev)) 149 return (ENXIO); 150 if (ofw_bus_is_compatible(dev, "ti,omap3-wdt")) { 151 device_set_desc(dev, "TI Watchdog Timer"); 152 return (BUS_PROBE_DEFAULT); 153 } 154 155 return (ENXIO); 156 } 157 158 static int 159 ti_wdt_attach(device_t dev) 160 { 161 struct ti_wdt_softc *sc; 162 int rid; 163 164 sc = device_get_softc(dev); 165 rid = 0; 166 sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, 167 RF_ACTIVE); 168 if (sc->sc_mem_res == NULL) { 169 device_printf(dev, "could not allocate memory resource\n"); 170 return (ENXIO); 171 } 172 sc->sc_bt = rman_get_bustag(sc->sc_mem_res); 173 sc->sc_bh = rman_get_bushandle(sc->sc_mem_res); 174 sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, RF_ACTIVE); 175 if (sc->sc_irq_res == NULL) { 176 device_printf(dev, "could not allocate interrupt resource\n"); 177 ti_wdt_detach(dev); 178 return (ENXIO); 179 } 180 if (bus_setup_intr(dev, sc->sc_irq_res, INTR_MPSAFE | INTR_TYPE_MISC, 181 NULL, ti_wdt_intr, sc, &sc->sc_intr) != 0) { 182 device_printf(dev, 183 "unable to setup the interrupt handler\n"); 184 ti_wdt_detach(dev); 185 return (ENXIO); 186 } 187 /* Reset, enable interrupts and stop the watchdog. */ 188 ti_wdt_reg_write(sc, TI_WDT_WDSC, 189 ti_wdt_reg_read(sc, TI_WDT_WDSC) | TI_WDSC_SR); 190 while (ti_wdt_reg_read(sc, TI_WDT_WDSC) & TI_WDSC_SR) 191 DELAY(10); 192 ti_wdt_reg_write(sc, TI_WDT_WIRQENSET, TI_IRQ_EN_OVF | TI_IRQ_EN_DLY); 193 ti_wdt_disable(sc); 194 if (bootverbose) 195 device_printf(dev, "revision: 0x%x\n", 196 ti_wdt_reg_read(sc, TI_WDT_WIDR)); 197 sc->sc_ev_tag = EVENTHANDLER_REGISTER(watchdog_list, ti_wdt_event, sc, 198 0); 199 200 return (0); 201 } 202 203 static int 204 ti_wdt_detach(device_t dev) 205 { 206 struct ti_wdt_softc *sc; 207 208 sc = device_get_softc(dev); 209 if (sc->sc_ev_tag) 210 EVENTHANDLER_DEREGISTER(watchdog_list, sc->sc_ev_tag); 211 if (sc->sc_intr) 212 bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intr); 213 if (sc->sc_irq_res) 214 bus_release_resource(dev, SYS_RES_IRQ, 215 rman_get_rid(sc->sc_irq_res), sc->sc_irq_res); 216 if (sc->sc_mem_res) 217 bus_release_resource(dev, SYS_RES_MEMORY, 218 rman_get_rid(sc->sc_mem_res), sc->sc_mem_res); 219 220 return (0); 221 } 222 223 static void 224 ti_wdt_intr(void *arg) 225 { 226 struct ti_wdt_softc *sc; 227 228 sc = arg; 229 DPRINTF("interrupt %p", sc); 230 ti_wdt_reg_write(sc, TI_WDT_WIRQSTAT, TI_IRQ_EV_OVF | TI_IRQ_EV_DLY); 231 /* TODO: handle interrupt */ 232 } 233 234 static void 235 ti_wdt_event(void *arg, unsigned int cmd, int *error) 236 { 237 struct ti_wdt_softc *sc; 238 uint8_t s; 239 uint32_t wldr; 240 uint32_t ptv; 241 242 sc = arg; 243 ti_wdt_disable(sc); 244 if (cmd == WD_TO_NEVER) { 245 *error = 0; 246 return; 247 } 248 DPRINTF("cmd 0x%x\n", cmd); 249 cmd &= WD_INTERVAL; 250 if (cmd < WD_TO_1SEC) { 251 *error = EINVAL; 252 return; 253 } 254 s = 1 << (cmd - WD_TO_1SEC); 255 DPRINTF("seconds %u\n", s); 256 /* 257 * Leave the pre-scaler with its default values: 258 * PTV = 0 == 2**0 == 1 259 * PRE = 1 (enabled) 260 * 261 * Compute the load register value assuming a 32kHz clock. 262 * See OVF_Rate in the WDT section of the AM335x TRM. 263 */ 264 ptv = 0; 265 wldr = 0xffffffff - (s * (32768 / (1 << ptv))) + 1; 266 DPRINTF("wldr 0x%x\n", wldr); 267 ti_wdt_reg_write(sc, TI_WDT_WLDR, wldr); 268 /* 269 * Trigger a timer reload. 270 */ 271 ti_wdt_reg_write(sc, TI_WDT_WTGR, 272 ti_wdt_reg_read(sc, TI_WDT_WTGR) + 1); 273 ti_wdt_reg_wait(sc, TI_W_PEND_WTGR); 274 ti_wdt_enable(sc); 275 *error = 0; 276 } 277