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: releng/10.2/sys/arm/ti/ti_wdt.c 276290 2014-12-27 05:11:34Z ian $");
   28 
   29 #include <sys/param.h>
   30 #include <sys/systm.h>
   31 #include <sys/bus.h>
   32 #include <sys/conf.h>
   33 #include <sys/kernel.h>
   34 #include <sys/module.h>
   35 #include <sys/malloc.h>
   36 #include <sys/rman.h>
   37 #include <sys/event.h>
   38 #include <sys/selinfo.h>
   39 #include <sys/watchdog.h>
   40 #include <machine/bus.h>
   41 #include <machine/cpu.h>
   42 #include <machine/frame.h>
   43 #include <machine/intr.h>
   44 
   45 #include <dev/fdt/fdt_common.h>
   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 #include <machine/fdt.h>
   52 
   53 #include <arm/ti/ti_prcm.h>
   54 #include <arm/ti/ti_wdt.h>
   55 
   56 #ifdef DEBUG
   57 #define DPRINTF(fmt, ...)       do {    \
   58         printf("%s: ", __func__);       \
   59         printf(fmt, __VA_ARGS__);       \
   60 } while (0)
   61 #else
   62 #define DPRINTF(fmt, ...)
   63 #endif
   64 
   65 static device_probe_t           ti_wdt_probe;
   66 static device_attach_t          ti_wdt_attach;
   67 static device_detach_t          ti_wdt_detach;
   68 static void                     ti_wdt_intr(void *);
   69 static void                     ti_wdt_event(void *, unsigned int, int *);
   70 
   71 struct ti_wdt_softc {
   72         struct resource         *sc_mem_res;
   73         struct resource         *sc_irq_res;
   74         void                    *sc_intr;
   75         bus_space_tag_t         sc_bt;
   76         bus_space_handle_t      sc_bh;
   77         eventhandler_tag        sc_ev_tag;
   78 };
   79 
   80 static device_method_t ti_wdt_methods[] = {
   81         DEVMETHOD(device_probe,         ti_wdt_probe),
   82         DEVMETHOD(device_attach,        ti_wdt_attach),
   83         DEVMETHOD(device_detach,        ti_wdt_detach),
   84 
   85         DEVMETHOD_END
   86 };
   87 
   88 static driver_t ti_wdt_driver = {
   89         "ti_wdt",
   90         ti_wdt_methods,
   91         sizeof(struct ti_wdt_softc)
   92 };
   93 
   94 static devclass_t ti_wdt_devclass;
   95 
   96 DRIVER_MODULE(ti_wdt, simplebus, ti_wdt_driver, ti_wdt_devclass, 0, 0);
   97 
   98 static __inline uint32_t
   99 ti_wdt_reg_read(struct ti_wdt_softc *sc, uint32_t reg)
  100 {
  101 
  102         return (bus_space_read_4(sc->sc_bt, sc->sc_bh, reg));
  103 }
  104 
  105 static __inline void
  106 ti_wdt_reg_write(struct ti_wdt_softc *sc, uint32_t reg, uint32_t val)
  107 {
  108 
  109         bus_space_write_4(sc->sc_bt, sc->sc_bh, reg, val);
  110 }
  111 
  112 /*
  113  * Wait for the write to a specific synchronised register to complete.
  114  */
  115 static __inline void
  116 ti_wdt_reg_wait(struct ti_wdt_softc *sc, uint32_t bit)
  117 {
  118 
  119         while (ti_wdt_reg_read(sc, TI_WDT_WWPS) & bit)
  120                 DELAY(10);
  121 }
  122 
  123 static __inline void
  124 ti_wdt_disable(struct ti_wdt_softc *sc)
  125 {
  126 
  127         DPRINTF("disabling watchdog %p\n", sc);
  128         ti_wdt_reg_write(sc, TI_WDT_WSPR, 0xAAAA);
  129         ti_wdt_reg_wait(sc, TI_W_PEND_WSPR);
  130         ti_wdt_reg_write(sc, TI_WDT_WSPR, 0x5555);
  131         ti_wdt_reg_wait(sc, TI_W_PEND_WSPR);
  132 }
  133 
  134 static __inline void
  135 ti_wdt_enable(struct ti_wdt_softc *sc)
  136 {
  137 
  138         DPRINTF("enabling watchdog %p\n", sc);
  139         ti_wdt_reg_write(sc, TI_WDT_WSPR, 0xBBBB);
  140         ti_wdt_reg_wait(sc, TI_W_PEND_WSPR);
  141         ti_wdt_reg_write(sc, TI_WDT_WSPR, 0x4444);
  142         ti_wdt_reg_wait(sc, TI_W_PEND_WSPR);
  143 }
  144 
  145 static int
  146 ti_wdt_probe(device_t dev)
  147 {
  148 
  149         if (!ofw_bus_status_okay(dev))
  150                 return (ENXIO);
  151         if (ofw_bus_is_compatible(dev, "ti,omap3-wdt")) {
  152                 device_set_desc(dev, "TI Watchdog Timer");
  153                 return (BUS_PROBE_DEFAULT);
  154         }
  155 
  156         return (ENXIO);
  157 }
  158 
  159 static int
  160 ti_wdt_attach(device_t dev)
  161 {
  162         struct ti_wdt_softc *sc;
  163         int rid;
  164 
  165         sc = device_get_softc(dev);
  166         rid = 0;
  167         sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
  168             RF_ACTIVE);
  169         if (sc->sc_mem_res == NULL) {
  170                 device_printf(dev, "could not allocate memory resource\n");
  171                 return (ENXIO);
  172         }
  173         sc->sc_bt = rman_get_bustag(sc->sc_mem_res);
  174         sc->sc_bh = rman_get_bushandle(sc->sc_mem_res);
  175         sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid, RF_ACTIVE);
  176         if (sc->sc_irq_res == NULL) {
  177                 device_printf(dev, "could not allocate interrupt resource\n");
  178                 ti_wdt_detach(dev);
  179                 return (ENXIO);
  180         }
  181         if (bus_setup_intr(dev, sc->sc_irq_res, INTR_MPSAFE | INTR_TYPE_MISC,
  182                 NULL, ti_wdt_intr, sc,  &sc->sc_intr) != 0) {
  183                 device_printf(dev,
  184                     "unable to setup the interrupt handler\n");
  185                 ti_wdt_detach(dev);
  186                 return (ENXIO);
  187         }
  188         /* Reset, enable interrupts and stop the watchdog. */
  189         ti_wdt_reg_write(sc, TI_WDT_WDSC,
  190             ti_wdt_reg_read(sc, TI_WDT_WDSC) | TI_WDSC_SR);
  191         while (ti_wdt_reg_read(sc, TI_WDT_WDSC) & TI_WDSC_SR)
  192                 DELAY(10);
  193         ti_wdt_reg_write(sc, TI_WDT_WIRQENSET, TI_IRQ_EN_OVF | TI_IRQ_EN_DLY);
  194         ti_wdt_disable(sc);
  195         if (bootverbose)
  196                 device_printf(dev, "revision: 0x%x\n",
  197                     ti_wdt_reg_read(sc, TI_WDT_WIDR));
  198         sc->sc_ev_tag = EVENTHANDLER_REGISTER(watchdog_list, ti_wdt_event, sc,
  199             0);
  200 
  201         return (0);
  202 }
  203 
  204 static int
  205 ti_wdt_detach(device_t dev)
  206 {
  207         struct ti_wdt_softc *sc;
  208 
  209         sc = device_get_softc(dev);
  210         if (sc->sc_ev_tag)
  211                 EVENTHANDLER_DEREGISTER(watchdog_list, sc->sc_ev_tag);
  212         if (sc->sc_intr)
  213                 bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intr);
  214         if (sc->sc_irq_res)
  215                 bus_release_resource(dev, SYS_RES_IRQ,
  216                     rman_get_rid(sc->sc_irq_res), sc->sc_irq_res);
  217         if (sc->sc_mem_res)
  218                 bus_release_resource(dev, SYS_RES_MEMORY,
  219                     rman_get_rid(sc->sc_mem_res),  sc->sc_mem_res);
  220 
  221         return (0);
  222 }
  223 
  224 static void
  225 ti_wdt_intr(void *arg)
  226 {
  227         struct ti_wdt_softc *sc;
  228 
  229         sc = arg;
  230         DPRINTF("interrupt %p", sc);
  231         ti_wdt_reg_write(sc, TI_WDT_WIRQSTAT, TI_IRQ_EV_OVF | TI_IRQ_EV_DLY);
  232         /* TODO: handle interrupt */
  233 }
  234 
  235 static void
  236 ti_wdt_event(void *arg, unsigned int cmd, int *error)
  237 {
  238         struct ti_wdt_softc *sc;
  239         uint8_t s;
  240         uint32_t wldr;
  241         uint32_t ptv;
  242 
  243         sc = arg;
  244         ti_wdt_disable(sc);
  245         if (cmd == WD_TO_NEVER) {
  246                 *error = 0;
  247                 return;
  248         }
  249         DPRINTF("cmd 0x%x\n", cmd);
  250         cmd &= WD_INTERVAL;
  251         if (cmd < WD_TO_1SEC) {
  252                 *error = EINVAL;
  253                 return;
  254         }
  255         s = 1 << (cmd - WD_TO_1SEC);
  256         DPRINTF("seconds %u\n", s);
  257         /*
  258          * Leave the pre-scaler with its default values:
  259          * PTV = 0 == 2**0 == 1
  260          * PRE = 1 (enabled)
  261          *
  262          * Compute the load register value assuming a 32kHz clock.
  263          * See OVF_Rate in the WDT section of the AM335x TRM.
  264          */
  265         ptv = 0;
  266         wldr = 0xffffffff - (s * (32768 / (1 << ptv))) + 1;
  267         DPRINTF("wldr 0x%x\n", wldr);
  268         ti_wdt_reg_write(sc, TI_WDT_WLDR, wldr);
  269         /*
  270          * Trigger a timer reload.
  271          */
  272         ti_wdt_reg_write(sc, TI_WDT_WTGR,
  273             ti_wdt_reg_read(sc, TI_WDT_WTGR) + 1);
  274         ti_wdt_reg_wait(sc, TI_W_PEND_WTGR);
  275         ti_wdt_enable(sc);
  276         *error = 0;
  277 }

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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