FreeBSD/Linux Kernel Cross Reference
sys/dev/dwwdt/dwwdt.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2020 BusyTech
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/param.h>
    #include <sys/eventhandler.h>
    #include <sys/kernel.h>
    #include <sys/types.h>
    #include <sys/bus.h>
    #include <sys/module.h>
    #include <sys/systm.h>
    #include <sys/sysctl.h>
    #include <sys/rman.h>
    #include <sys/resource.h>
    #include <sys/watchdog.h>
    
    #include <machine/bus.h>
    #include <machine/resource.h>
    
    #include <dev/extres/clk/clk.h>
    #include <dev/fdt/fdt_common.h>
    #include <dev/ofw/openfirm.h>
    #include <dev/ofw/ofw_bus.h>
    #include <dev/ofw/ofw_bus_subr.h>
    
    /* Registers */
    #define DWWDT_CR                0x00
    #define DWWDT_CR_WDT_EN         (1 << 0)
    #define DWWDT_CR_RESP_MODE      (1 << 1)
    #define DWWDT_TORR              0x04
    #define DWWDT_CCVR              0x08
    #define DWWDT_CRR               0x0C
    #define DWWDT_CRR_KICK          0x76
    #define DWWDT_STAT              0x10
    #define DWWDT_STAT_STATUS       0x01
    #define DWWDT_EOI               0x14
    
    #define DWWDT_READ4(sc, reg)            bus_read_4((sc)->sc_mem_res, (reg))
    #define DWWDT_WRITE4(sc, reg, val)      \
            bus_write_4((sc)->sc_mem_res, (reg), (val))
    
    /*
     * 47 = 16 (timeout shift of dwwdt) + 30 (1s ~= 2 ** 30ns) + 1
     * (pre-restart delay)
     */
    #define DWWDT_EXP_OFFSET        47
    
    struct dwwdt_softc {
            device_t                 sc_dev;
            struct resource         *sc_mem_res;
            struct resource         *sc_irq_res;
            void                    *sc_intr_cookie;
            clk_t                    sc_clk;
            uint64_t                 sc_clk_freq;
            eventhandler_tag         sc_evtag;
            int                      sc_mem_rid;
            int                      sc_irq_rid;
            enum {
                    DWWDT_STOPPED,
                    DWWDT_RUNNING,
            }                        sc_status;
    };
    
    static struct ofw_compat_data compat_data[] = {
            { "snps,dw-wdt",                1 },
            { NULL,                         0 }
    };
    
    SYSCTL_NODE(_dev, OID_AUTO, dwwdt, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
        "Synopsys Designware watchdog timer");
    
    /* Setting this to true disables full restart mode. */
    static bool dwwdt_prevent_restart = false;
    SYSCTL_BOOL(_dev_dwwdt, OID_AUTO, prevent_restart, CTLFLAG_RW | CTLFLAG_MPSAFE,
        &dwwdt_prevent_restart, 0, "Disable system reset on timeout");
    
   static bool dwwdt_debug_enabled = false;
   SYSCTL_BOOL(_dev_dwwdt, OID_AUTO, debug, CTLFLAG_RW | CTLFLAG_MPSAFE,
       &dwwdt_debug_enabled, 0, "Enable debug mode");
   
   static bool dwwdt_panic_first = true;
   SYSCTL_BOOL(_dev_dwwdt, OID_AUTO, panic_first, CTLFLAG_RW | CTLFLAG_MPSAFE,
       &dwwdt_panic_first, 0,
       "Try to panic on timeout, reset on another timeout");
   
   static int dwwdt_probe(device_t);
   static int dwwdt_attach(device_t);
   static int dwwdt_detach(device_t);
   static int dwwdt_shutdown(device_t);
   
   static void dwwdt_intr(void *);
   static void dwwdt_event(void *, unsigned int, int *);
   
   /* Helpers */
   static inline void dwwdt_start(struct dwwdt_softc *sc);
   static inline bool dwwdt_started(const struct dwwdt_softc *sc);
   static inline void dwwdt_stop(struct dwwdt_softc *sc);
   static inline void dwwdt_set_timeout(const struct dwwdt_softc *sc, int val);
   
   static void dwwdt_debug(device_t);
   
   static void
   dwwdt_debug(device_t dev)
   {
           /*
            * Reading from EOI may clear interrupt flag.
            */
           const struct dwwdt_softc *sc = device_get_softc(dev);
   
           device_printf(dev, "Registers dump: \n");
           device_printf(dev, "  CR:   %08x\n", DWWDT_READ4(sc, DWWDT_CR));
           device_printf(dev, "  CCVR: %08x\n", DWWDT_READ4(sc, DWWDT_CCVR));
           device_printf(dev, "  CRR:  %08x\n", DWWDT_READ4(sc, DWWDT_CRR));
           device_printf(dev, "  STAT: %08x\n", DWWDT_READ4(sc, DWWDT_STAT));
   
           device_printf(dev, "Clock: %s\n", clk_get_name(sc->sc_clk));
           device_printf(dev, "  FREQ: %lu\n", sc->sc_clk_freq);
   }
   
   static inline bool
   dwwdt_started(const struct dwwdt_softc *sc)
   {
   
           /* CR_WDT_E bit can be clear only by full CPU reset. */
           return ((DWWDT_READ4(sc, DWWDT_CR) & DWWDT_CR_WDT_EN) != 0);
   }
   
   static void inline
   dwwdt_start(struct dwwdt_softc *sc)
   {
           uint32_t val;
   
           /* Enable watchdog */
           val = DWWDT_READ4(sc, DWWDT_CR);
           val |= DWWDT_CR_WDT_EN | DWWDT_CR_RESP_MODE;
           DWWDT_WRITE4(sc, DWWDT_CR, val);
           sc->sc_status = DWWDT_RUNNING;
   }
   
   static void inline
   dwwdt_stop(struct dwwdt_softc *sc)
   {
   
           sc->sc_status = DWWDT_STOPPED;
           dwwdt_set_timeout(sc, 0x0f);
   }
   
   static void inline
   dwwdt_set_timeout(const struct dwwdt_softc *sc, int val)
   {
   
           DWWDT_WRITE4(sc, DWWDT_TORR, val);
           DWWDT_WRITE4(sc, DWWDT_CRR, DWWDT_CRR_KICK);
   }
   
   static void
   dwwdt_intr(void *arg)
   {
           struct dwwdt_softc *sc = arg;
   
           KASSERT((DWWDT_READ4(sc, DWWDT_STAT) & DWWDT_STAT_STATUS) != 0,
               ("Missing interrupt status bit?"));
   
           if (dwwdt_prevent_restart || sc->sc_status == DWWDT_STOPPED) {
                   /*
                    * Confirm interrupt reception. Restart counter.
                    * This also emulates stopping watchdog.
                    */
                   (void)DWWDT_READ4(sc, DWWDT_EOI);
                   return;
           }
   
           if (dwwdt_panic_first)
                   panic("dwwdt pre-timeout interrupt");
   }
   
   static void
   dwwdt_event(void *arg, unsigned int cmd, int *error)
   {
           struct dwwdt_softc *sc = arg;
           const int exponent = flsl(sc->sc_clk_freq);
           int timeout;
           int val;
   
           timeout = cmd & WD_INTERVAL;
           val = MAX(0, timeout + exponent - DWWDT_EXP_OFFSET + 1);
   
           dwwdt_stop(sc);
           if (cmd == 0 || val > 0x0f) {
                   /*
                    * Set maximum time between interrupts and Leave watchdog
                    * disabled.
                    */
                   return;
           }
   
           dwwdt_set_timeout(sc, val);
           dwwdt_start(sc);
           *error = 0;
   
           if (dwwdt_debug_enabled)
                   dwwdt_debug(sc->sc_dev);
   }
   
   static int
   dwwdt_probe(device_t dev)
   {
           if (!ofw_bus_status_okay(dev))
                   return (ENXIO);
   
           if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data)
                   return (ENXIO);
   
           device_set_desc(dev, "Synopsys Designware watchdog timer");
           return (BUS_PROBE_DEFAULT);
   }
   
   static int
   dwwdt_attach(device_t dev)
   {
           struct dwwdt_softc *sc;
   
           sc = device_get_softc(dev);
           sc->sc_dev = dev;
   
           sc->sc_mem_rid = 0;
           sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
               &sc->sc_mem_rid, RF_ACTIVE);
           if (sc->sc_mem_res == NULL) {
                   device_printf(dev, "cannot allocate memory resource\n");
                   goto err_no_mem;
           }
   
           sc->sc_irq_rid = 0;
           sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ,
               &sc->sc_irq_rid, RF_ACTIVE);
           if (sc->sc_irq_res == NULL) {
                   device_printf(dev, "cannot allocate ireq resource\n");
                   goto err_no_irq;
           }
   
           sc->sc_intr_cookie = NULL;
           if (bus_setup_intr(dev, sc->sc_irq_res, INTR_MPSAFE | INTR_TYPE_MISC,
               NULL, dwwdt_intr, sc, &sc->sc_intr_cookie) != 0) {
                   device_printf(dev, "cannot setup interrupt routine\n");
                   goto err_no_intr;
           }
   
           if (clk_get_by_ofw_index(dev, 0, 0, &sc->sc_clk) != 0) {
                   device_printf(dev, "cannot find clock\n");
                   goto err_no_clock;
           }
   
           if (clk_enable(sc->sc_clk) != 0) {
                   device_printf(dev, "cannot enable clock\n");
                   goto err_no_freq;
           }
   
           if (clk_get_freq(sc->sc_clk, &sc->sc_clk_freq) != 0) {
                   device_printf(dev, "cannot get clock frequency\n");
                   goto err_no_freq;
           }
   
           if (sc->sc_clk_freq == 0UL)
                   goto err_no_freq;
   
           sc->sc_evtag = EVENTHANDLER_REGISTER(watchdog_list, dwwdt_event, sc, 0);
           sc->sc_status = DWWDT_STOPPED;
   
           return (bus_generic_attach(dev));
   
   err_no_freq:
           clk_release(sc->sc_clk);
   err_no_clock:
           bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intr_cookie);
   err_no_intr:
           bus_release_resource(dev, SYS_RES_IRQ, sc->sc_irq_rid, sc->sc_irq_res);
   err_no_irq:
           bus_release_resource(dev, SYS_RES_MEMORY, sc->sc_mem_rid,
               sc->sc_mem_res);
   err_no_mem:
           return (ENXIO);
   }
   
   static int
   dwwdt_detach(device_t dev)
   {
           struct dwwdt_softc *sc = device_get_softc(dev);
   
           if (dwwdt_started(sc)) {
                   /*
                    * Once started it cannot be stopped. Prevent module unload
                    * instead.
                    */
                   return (EBUSY);
           }
   
           EVENTHANDLER_DEREGISTER(watchdog_list, sc->sc_evtag);
           sc->sc_evtag = NULL;
   
           if (sc->sc_clk != NULL)
                   clk_release(sc->sc_clk);
   
           if (sc->sc_intr_cookie != NULL)
                   bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intr_cookie);
   
           if (sc->sc_irq_res) {
                   bus_release_resource(dev, SYS_RES_IRQ, sc->sc_irq_rid,
                       sc->sc_irq_res);
           }
   
           if (sc->sc_mem_res) {
                   bus_release_resource(dev, SYS_RES_MEMORY, sc->sc_mem_rid,
                       sc->sc_mem_res);
           }
   
           return (bus_generic_detach(dev));
   }
   
   static int
   dwwdt_shutdown(device_t dev)
   {
           struct dwwdt_softc *sc;
   
           sc = device_get_softc(dev);
   
           /* Prevent restarts during shutdown. */
           dwwdt_prevent_restart = true;
           dwwdt_stop(sc);
           return (bus_generic_shutdown(dev));
   }
   
   static device_method_t dwwdt_methods[] = {
           DEVMETHOD(device_probe, dwwdt_probe),
           DEVMETHOD(device_attach, dwwdt_attach),
           DEVMETHOD(device_detach, dwwdt_detach),
           DEVMETHOD(device_shutdown, dwwdt_shutdown),
   
           {0, 0}
   };
   
   static driver_t dwwdt_driver = {
           "dwwdt",
           dwwdt_methods,
           sizeof(struct dwwdt_softc),
   };
   
   DRIVER_MODULE(dwwdt, simplebus, dwwdt_driver, NULL, NULL);
   MODULE_VERSION(dwwdt, 1);
   OFWBUS_PNP_INFO(compat_data);

Cache object: 85471f518d81497048702d0ee6d32237