FreeBSD/Linux Kernel Cross Reference
sys/arm/mv/armada38x/rtc.c

     /*-
      * Copyright (c) 2015 Semihalf.
      * Copyright (c) 2015 Stormshield.
      * All rights reserved.
      *
      * 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/cdefs.h>
    __FBSDID("$FreeBSD: releng/11.1/sys/arm/mv/armada38x/rtc.c 294434 2016-01-20 14:18:49Z zbb $");
    
    #include <sys/param.h>
    #include <sys/bus.h>
    #include <sys/lock.h>
    #include <sys/time.h>
    #include <sys/proc.h>
    #include <sys/conf.h>
    #include <sys/rman.h>
    #include <sys/clock.h>
    #include <sys/systm.h>
    #include <sys/mutex.h>
    #include <sys/types.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/resource.h>
    
    #include <machine/bus.h>
    #include <machine/resource.h>
    
    #include <dev/ofw/ofw_bus.h>
    #include <dev/ofw/ofw_bus_subr.h>
    
    #include "clock_if.h"
    
    #define RTC_RES_US              1000000
    #define HALF_OF_SEC_NS          500000000
    
    #define RTC_STATUS              0x0
    #define RTC_TIME                0xC
    
    #define MV_RTC_LOCK(sc)         mtx_lock(&(sc)->mutex)
    #define MV_RTC_UNLOCK(sc)       mtx_unlock(&(sc)->mutex)
    
    static struct resource_spec res_spec[] = {
            { SYS_RES_MEMORY,       0,      RF_ACTIVE },
            { -1, 0 }
    };
    
    struct mv_rtc_softc {
            device_t        dev;
            struct resource *res;
            struct mtx      mutex;
    };
    
    static int mv_rtc_probe(device_t dev);
    static int mv_rtc_attach(device_t dev);
    static int mv_rtc_detach(device_t dev);
    
    static int mv_rtc_gettime(device_t dev, struct timespec *ts);
    static int mv_rtc_settime(device_t dev, struct timespec *ts);
    
    static uint32_t mv_rtc_reg_read(struct mv_rtc_softc *sc, bus_size_t off);
    static int mv_rtc_reg_write(struct mv_rtc_softc *sc, bus_size_t off,
        uint32_t val);
    
    static device_method_t mv_rtc_methods[] = {
            DEVMETHOD(device_probe,         mv_rtc_probe),
            DEVMETHOD(device_attach,        mv_rtc_attach),
            DEVMETHOD(device_detach,        mv_rtc_detach),
    
            DEVMETHOD(clock_gettime,        mv_rtc_gettime),
            DEVMETHOD(clock_settime,        mv_rtc_settime),
    
            { 0, 0 },
    };
    
    static driver_t mv_rtc_driver = {
            "rtc",
            mv_rtc_methods,
            sizeof(struct mv_rtc_softc),
   };
   
   static devclass_t mv_rtc_devclass;
   
   DRIVER_MODULE(mv_rtc, simplebus, mv_rtc_driver, mv_rtc_devclass, 0, 0);
   
   static int
   mv_rtc_probe(device_t dev)
   {
   
           if (!ofw_bus_status_okay(dev))
                   return (ENXIO);
   
           if (!ofw_bus_is_compatible(dev, "marvell,armada-380-rtc"))
                   return (ENXIO);
   
           device_set_desc(dev, "Marvell Integrated RTC");
   
           return (BUS_PROBE_DEFAULT);
   }
   
   static int
   mv_rtc_attach(device_t dev)
   {
           struct mv_rtc_softc *sc;
           int unit, ret;
   
           unit = device_get_unit(dev);
   
           sc = device_get_softc(dev);
           sc->dev = dev;
   
           clock_register(dev, RTC_RES_US);
   
           mtx_init(&sc->mutex, device_get_nameunit(dev), NULL, MTX_DEF);
   
           ret = bus_alloc_resources(dev, res_spec, &sc->res);
           if (ret != 0) {
                   device_printf(dev, "could not allocate resources\n");
                   mtx_destroy(&sc->mutex);
                   return (ENXIO);
           }
   
           return (0);
   }
   
   static int
   mv_rtc_detach(device_t dev)
   {
           struct mv_rtc_softc *sc;
   
           sc = device_get_softc(dev);
   
           mtx_destroy(&sc->mutex);
   
           bus_release_resources(dev, res_spec, &sc->res);
   
           return (0);
   }
   
   static int
   mv_rtc_gettime(device_t dev, struct timespec *ts)
   {
           struct mv_rtc_softc *sc;
           uint32_t val, val_check;
   
           sc = device_get_softc(dev);
   
           MV_RTC_LOCK(sc);
           /*
            * According to HW Errata if more than one second between
            * two time reads is detected, then read once again
            */
           val = mv_rtc_reg_read(sc, RTC_TIME);
           val_check = mv_rtc_reg_read(sc, RTC_TIME);
           if (val_check - val > 1)
                   val_check = mv_rtc_reg_read(sc, RTC_TIME);
   
           MV_RTC_UNLOCK(sc);
   
           ts->tv_sec = val_check;
           /* RTC resolution is 1 sec */
           ts->tv_nsec = 0;
   
           return (0);
   }
   
   static int
   mv_rtc_settime(device_t dev, struct timespec *ts)
   {
           struct mv_rtc_softc *sc;
   
           sc = device_get_softc(dev);
   
           /* RTC resolution is 1 sec */
           if (ts->tv_nsec >= HALF_OF_SEC_NS)
                   ts->tv_sec++;
           ts->tv_nsec = 0;
   
           MV_RTC_LOCK(sc);
   
           /*
            * According to errata FE-3124064, Write to RTC TIME register
            * may fail. As a workaround, before writing to RTC TIME register,
            * issue a dummy write of 0x0 twice to RTC Status register.
            */
           mv_rtc_reg_write(sc, RTC_STATUS, 0x0);
           mv_rtc_reg_write(sc, RTC_STATUS, 0x0);
           mv_rtc_reg_write(sc, RTC_TIME, ts->tv_sec);
   
           MV_RTC_UNLOCK(sc);
   
           return (0);
   }
   
   static uint32_t
   mv_rtc_reg_read(struct mv_rtc_softc *sc, bus_size_t off)
   {
   
           return (bus_read_4(sc->res, off));
   }
   
   /*
    * According to the datasheet, the OS should wait 5us after every
    * register write to the RTC hard macro so that the required update
    * can occur without holding off the system bus
    */
   static int
   mv_rtc_reg_write(struct mv_rtc_softc *sc, bus_size_t off, uint32_t val)
   {
   
           bus_write_4(sc->res, off, val);
           DELAY(5);
   
           return (0);
   }

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