ti_wdt.c

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    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 DRIVER_MODULE(ti_wdt, simplebus, ti_wdt_driver, 0, 0);
   93 MODULE_DEPEND(ti_wdt, ti_sysc, 1, 1, 1);
   94 
   95 static __inline uint32_t
   96 ti_wdt_reg_read(struct ti_wdt_softc *sc, uint32_t reg)
   97 {
   98 
   99         return (bus_space_read_4(sc->sc_bt, sc->sc_bh, reg));
  100 }
  101 
  102 static __inline void
  103 ti_wdt_reg_write(struct ti_wdt_softc *sc, uint32_t reg, uint32_t val)
  104 {
  105 
  106         bus_space_write_4(sc->sc_bt, sc->sc_bh, reg, val);
  107 }
  108 
  109 /*
  110  * Wait for the write to a specific synchronised register to complete.
  111  */
  112 static __inline void
  113 ti_wdt_reg_wait(struct ti_wdt_softc *sc, uint32_t bit)
  114 {
  115 
  116         while (ti_wdt_reg_read(sc, TI_WDT_WWPS) & bit)
  117                 DELAY(10);
  118 }
  119 
  120 static __inline void
  121 ti_wdt_disable(struct ti_wdt_softc *sc)
  122 {
  123 
  124         DPRINTF("disabling watchdog %p\n", sc);
  125         ti_wdt_reg_write(sc, TI_WDT_WSPR, 0xAAAA);
  126         ti_wdt_reg_wait(sc, TI_W_PEND_WSPR);
  127         ti_wdt_reg_write(sc, TI_WDT_WSPR, 0x5555);
  128         ti_wdt_reg_wait(sc, TI_W_PEND_WSPR);
  129 }
  130 
  131 static __inline void
  132 ti_wdt_enable(struct ti_wdt_softc *sc)
  133 {
  134 
  135         DPRINTF("enabling watchdog %p\n", sc);
  136         ti_wdt_reg_write(sc, TI_WDT_WSPR, 0xBBBB);
  137         ti_wdt_reg_wait(sc, TI_W_PEND_WSPR);
  138         ti_wdt_reg_write(sc, TI_WDT_WSPR, 0x4444);
  139         ti_wdt_reg_wait(sc, TI_W_PEND_WSPR);
  140 }
  141 
  142 static int
  143 ti_wdt_probe(device_t dev)
  144 {
  145 
  146         if (!ofw_bus_status_okay(dev))
  147                 return (ENXIO);
  148         if (ofw_bus_is_compatible(dev, "ti,omap3-wdt")) {
  149                 device_set_desc(dev, "TI Watchdog Timer");
  150                 return (BUS_PROBE_DEFAULT);
  151         }
  152 
  153         return (ENXIO);
  154 }
  155 
  156 static int
  157 ti_wdt_attach(device_t dev)
  158 {
  159         struct ti_wdt_softc *sc;
  160         int rid;
  161 
  162         sc = device_get_softc(dev);
  163         rid = 0;
  164         sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
  165             RF_ACTIVE);
  166         if (sc->sc_mem_res == NULL) {
  167                 device_printf(dev, "could not allocate memory resource\n");
  168                 return (ENXIO);
  169         }
  170         sc->sc_bt = rman_get_bustag(sc->sc_mem_res);
  171         sc->sc_bh = rman_get_bushandle(sc->sc_mem_res);
  172         sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, RF_ACTIVE);
  173         if (sc->sc_irq_res == NULL) {
  174                 device_printf(dev, "could not allocate interrupt resource\n");
  175                 ti_wdt_detach(dev);
  176                 return (ENXIO);
  177         }
  178         if (bus_setup_intr(dev, sc->sc_irq_res, INTR_MPSAFE | INTR_TYPE_MISC,
  179                 NULL, ti_wdt_intr, sc,  &sc->sc_intr) != 0) {
  180                 device_printf(dev,
  181                     "unable to setup the interrupt handler\n");
  182                 ti_wdt_detach(dev);
  183                 return (ENXIO);
  184         }
  185         /* Reset, enable interrupts and stop the watchdog. */
  186         ti_wdt_reg_write(sc, TI_WDT_WDSC,
  187             ti_wdt_reg_read(sc, TI_WDT_WDSC) | TI_WDSC_SR);
  188         while (ti_wdt_reg_read(sc, TI_WDT_WDSC) & TI_WDSC_SR)
  189                 DELAY(10);
  190         ti_wdt_reg_write(sc, TI_WDT_WIRQENSET, TI_IRQ_EN_OVF | TI_IRQ_EN_DLY);
  191         ti_wdt_disable(sc);
  192         if (bootverbose)
  193                 device_printf(dev, "revision: 0x%x\n",
  194                     ti_wdt_reg_read(sc, TI_WDT_WIDR));
  195         sc->sc_ev_tag = EVENTHANDLER_REGISTER(watchdog_list, ti_wdt_event, sc,
  196             0);
  197 
  198         return (0);
  199 }
  200 
  201 static int
  202 ti_wdt_detach(device_t dev)
  203 {
  204         struct ti_wdt_softc *sc;
  205 
  206         sc = device_get_softc(dev);
  207         if (sc->sc_ev_tag)
  208                 EVENTHANDLER_DEREGISTER(watchdog_list, sc->sc_ev_tag);
  209         if (sc->sc_intr)
  210                 bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intr);
  211         if (sc->sc_irq_res)
  212                 bus_release_resource(dev, SYS_RES_IRQ,
  213                     rman_get_rid(sc->sc_irq_res), sc->sc_irq_res);
  214         if (sc->sc_mem_res)
  215                 bus_release_resource(dev, SYS_RES_MEMORY,
  216                     rman_get_rid(sc->sc_mem_res),  sc->sc_mem_res);
  217 
  218         return (0);
  219 }
  220 
  221 static void
  222 ti_wdt_intr(void *arg)
  223 {
  224         struct ti_wdt_softc *sc;
  225 
  226         sc = arg;
  227         DPRINTF("interrupt %p", sc);
  228         ti_wdt_reg_write(sc, TI_WDT_WIRQSTAT, TI_IRQ_EV_OVF | TI_IRQ_EV_DLY);
  229         /* TODO: handle interrupt */
  230 }
  231 
  232 static void
  233 ti_wdt_event(void *arg, unsigned int cmd, int *error)
  234 {
  235         struct ti_wdt_softc *sc;
  236         uint8_t s;
  237         uint32_t wldr;
  238         uint32_t ptv;
  239 
  240         sc = arg;
  241         ti_wdt_disable(sc);
  242         if (cmd == WD_TO_NEVER) {
  243                 *error = 0;
  244                 return;
  245         }
  246         DPRINTF("cmd 0x%x\n", cmd);
  247         cmd &= WD_INTERVAL;
  248         if (cmd < WD_TO_1SEC) {
  249                 *error = EINVAL;
  250                 return;
  251         }
  252         s = 1 << (cmd - WD_TO_1SEC);
  253         DPRINTF("seconds %u\n", s);
  254         /*
  255          * Leave the pre-scaler with its default values:
  256          * PTV = 0 == 2**0 == 1
  257          * PRE = 1 (enabled)
  258          *
  259          * Compute the load register value assuming a 32kHz clock.
  260          * See OVF_Rate in the WDT section of the AM335x TRM.
  261          */
  262         ptv = 0;
  263         wldr = 0xffffffff - (s * (32768 / (1 << ptv))) + 1;
  264         DPRINTF("wldr 0x%x\n", wldr);
  265         ti_wdt_reg_write(sc, TI_WDT_WLDR, wldr);
  266         /*
  267          * Trigger a timer reload.
  268          */
  269         ti_wdt_reg_write(sc, TI_WDT_WTGR,
  270             ti_wdt_reg_read(sc, TI_WDT_WTGR) + 1);
  271         ti_wdt_reg_wait(sc, TI_W_PEND_WTGR);
  272         ti_wdt_enable(sc);
  273         *error = 0;
  274 }

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FreeBSD/Linux Kernel Cross Reference sys/arm/ti/ti_wdt.c

FreeBSD/Linux Kernel Cross Reference
sys/arm/ti/ti_wdt.c