bcm2835_wdog.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2012 Alexander Rybalko <ray@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 #include <sys/cdefs.h>
   29 __FBSDID("$FreeBSD$");
   30 
   31 #include <sys/param.h>
   32 #include <sys/bus.h>
   33 #include <sys/eventhandler.h>
   34 #include <sys/kernel.h>
   35 #include <sys/lock.h>
   36 #include <sys/module.h>
   37 #include <sys/mutex.h>
   38 #include <sys/reboot.h>
   39 #include <sys/rman.h>
   40 #include <sys/systm.h>
   41 #include <sys/watchdog.h>
   42 
   43 #include <dev/ofw/openfirm.h>
   44 #include <dev/ofw/ofw_bus.h>
   45 #include <dev/ofw/ofw_bus_subr.h>
   46 
   47 #include <machine/bus.h>
   48 #include <machine/machdep.h>
   49 
   50 #include <arm/broadcom/bcm2835/bcm2835_wdog.h>
   51 
   52 #define BCM2835_PASSWORD        0x5a
   53 
   54 #define BCM2835_WDOG_RESET      0
   55 #define BCM2835_PASSWORD_MASK   0xff000000
   56 #define BCM2835_PASSWORD_SHIFT  24
   57 #define BCM2835_WDOG_TIME_MASK  0x000fffff
   58 #define BCM2835_WDOG_TIME_SHIFT 0
   59 
   60 #define READ(_sc, _r) bus_space_read_4((_sc)->bst, (_sc)->bsh, (_r) + (_sc)->regs_offset)
   61 #define WRITE(_sc, _r, _v) bus_space_write_4((_sc)->bst, (_sc)->bsh, (_r) + (_sc)->regs_offset, (_v))
   62 
   63 #define BCM2835_RSTC_WRCFG_CLR          0xffffffcf
   64 #define BCM2835_RSTC_WRCFG_SET          0x00000030
   65 #define BCM2835_RSTC_WRCFG_FULL_RESET   0x00000020
   66 #define BCM2835_RSTC_RESET              0x00000102
   67 
   68 #define BCM2835_RSTC_REG        0x00
   69 #define BCM2835_RSTS_REG        0x04
   70 #define BCM2835_WDOG_REG        0x08
   71 
   72 static struct bcmwd_softc *bcmwd_lsc = NULL;
   73 
   74 struct bcmwd_softc {
   75         device_t                dev;
   76         struct resource *       res;
   77         bus_space_tag_t         bst;
   78         bus_space_handle_t      bsh;
   79         int                     wdog_armed;
   80         int                     wdog_period;
   81         char                    wdog_passwd;
   82         struct mtx              mtx;
   83         int                     regs_offset;
   84 };
   85 
   86 #define BSD_DTB         1
   87 #define UPSTREAM_DTB    2
   88 #define UPSTREAM_DTB_REGS_OFFSET        0x1c
   89 
   90 static struct ofw_compat_data compat_data[] = {
   91         {"broadcom,bcm2835-wdt",        BSD_DTB},
   92         {"brcm,bcm2835-pm-wdt",         UPSTREAM_DTB},
   93         {"brcm,bcm2835-pm",             UPSTREAM_DTB},
   94         {NULL,                          0}
   95 };
   96 
   97 static void bcmwd_watchdog_fn(void *private, u_int cmd, int *error);
   98 static void bcmwd_reboot_system(void *, int);
   99 
  100 static int
  101 bcmwd_probe(device_t dev)
  102 {
  103 
  104         if (!ofw_bus_status_okay(dev))
  105                 return (ENXIO);
  106 
  107         if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
  108                 return (ENXIO);
  109 
  110         device_set_desc(dev, "BCM2708/2835 Watchdog");
  111 
  112         return (BUS_PROBE_DEFAULT);
  113 }
  114 
  115 static int
  116 bcmwd_attach(device_t dev)
  117 {
  118         struct bcmwd_softc *sc;
  119         int rid;
  120 
  121         if (bcmwd_lsc != NULL)
  122                 return (ENXIO);
  123 
  124         sc = device_get_softc(dev);
  125         sc->wdog_period = 7;
  126         sc->wdog_passwd = BCM2835_PASSWORD;
  127         sc->wdog_armed = 0;
  128         sc->dev = dev;
  129 
  130         rid = 0;
  131         sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
  132         if (sc->res == NULL) {
  133                 device_printf(dev, "could not allocate memory resource\n");
  134                 return (ENXIO);
  135         }
  136 
  137         sc->bst = rman_get_bustag(sc->res);
  138         sc->bsh = rman_get_bushandle(sc->res);
  139 
  140         /* compensate base address difference */
  141         if (ofw_bus_search_compatible(dev, compat_data)->ocd_data
  142            == UPSTREAM_DTB)
  143                 sc->regs_offset = UPSTREAM_DTB_REGS_OFFSET;
  144 
  145         bcmwd_lsc = sc;
  146         mtx_init(&sc->mtx, "BCM2835 Watchdog", "bcmwd", MTX_DEF);
  147         EVENTHANDLER_REGISTER(watchdog_list, bcmwd_watchdog_fn, sc, 0);
  148 
  149         /*
  150          * Handle reboot events. This needs to happen with slightly greater
  151          * priority than the PSCI handler, since PSCI reset is not properly
  152          * implemented on the Pi and it just puts the Pi into a halt
  153          * state.
  154          */
  155         EVENTHANDLER_REGISTER(shutdown_final, bcmwd_reboot_system, sc,
  156             SHUTDOWN_PRI_LAST-1);
  157 
  158         return (0);
  159 }
  160 
  161 static void
  162 bcmwd_watchdog_fn(void *private, u_int cmd, int *error)
  163 {
  164         struct bcmwd_softc *sc;
  165         uint64_t sec;
  166         uint32_t ticks, reg;
  167 
  168         sc = private;
  169         mtx_lock(&sc->mtx);
  170 
  171         cmd &= WD_INTERVAL;
  172 
  173         if (cmd > 0) {
  174                 sec = ((uint64_t)1 << (cmd & WD_INTERVAL)) / 1000000000;
  175                 if (sec == 0 || sec > 15) {
  176                         /*
  177                          * Can't arm
  178                          * disable watchdog as watchdog(9) requires
  179                          */
  180                         device_printf(sc->dev,
  181                             "Can't arm, timeout must be between 1-15 seconds\n");
  182                         WRITE(sc, BCM2835_RSTC_REG,
  183                             (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) |
  184                             BCM2835_RSTC_RESET);
  185                         mtx_unlock(&sc->mtx);
  186                         *error = EINVAL;
  187                         return;
  188                 }
  189 
  190                 ticks = (sec << 16) & BCM2835_WDOG_TIME_MASK;
  191                 reg = (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) | ticks;
  192                 WRITE(sc, BCM2835_WDOG_REG, reg);
  193 
  194                 reg = READ(sc, BCM2835_RSTC_REG);
  195                 reg &= BCM2835_RSTC_WRCFG_CLR;
  196                 reg |= BCM2835_RSTC_WRCFG_FULL_RESET;
  197                 reg |= (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT);
  198                 WRITE(sc, BCM2835_RSTC_REG, reg);
  199 
  200                 *error = 0;
  201         }
  202         else
  203                 WRITE(sc, BCM2835_RSTC_REG,
  204                     (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) |
  205                     BCM2835_RSTC_RESET);
  206 
  207         mtx_unlock(&sc->mtx);
  208 }
  209 
  210 void
  211 bcmwd_watchdog_reset(void)
  212 {
  213 
  214         if (bcmwd_lsc == NULL)
  215                 return;
  216 
  217         WRITE(bcmwd_lsc, BCM2835_WDOG_REG,
  218             (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) | 10);
  219 
  220         WRITE(bcmwd_lsc, BCM2835_RSTC_REG,
  221             (READ(bcmwd_lsc, BCM2835_RSTC_REG) & BCM2835_RSTC_WRCFG_CLR) |
  222                 (BCM2835_PASSWORD << BCM2835_PASSWORD_SHIFT) |
  223                 BCM2835_RSTC_WRCFG_FULL_RESET);
  224 }
  225 
  226 static void
  227 bcmwd_reboot_system(void *sc, int howto)
  228 {
  229         int cmd, error = 0;
  230 
  231         /* Only handle reset. */
  232         if (howto & RB_HALT || howto & RB_POWEROFF)
  233                 return;
  234 
  235         printf("Resetting system ... ");
  236 
  237         cmd = WD_TO_1SEC;
  238         bcmwd_watchdog_fn(sc, cmd, &error);
  239 
  240         /* Wait for watchdog timeout. */
  241         DELAY(2000000);
  242 
  243         /* Not reached ... one hopes. */
  244         printf("failed to reset (errno %d).\n", error);
  245 }
  246 
  247 static device_method_t bcmwd_methods[] = {
  248         DEVMETHOD(device_probe, bcmwd_probe),
  249         DEVMETHOD(device_attach, bcmwd_attach),
  250 
  251         DEVMETHOD_END
  252 };
  253 
  254 static driver_t bcmwd_driver = {
  255         "bcmwd",
  256         bcmwd_methods,
  257         sizeof(struct bcmwd_softc),
  258 };
  259 
  260 DRIVER_MODULE(bcmwd, simplebus, bcmwd_driver, 0, 0);

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FreeBSD/Linux Kernel Cross Reference sys/arm/broadcom/bcm2835/bcm2835_wdog.c

FreeBSD/Linux Kernel Cross Reference
sys/arm/broadcom/bcm2835/bcm2835_wdog.c