FreeBSD/Linux Kernel Cross Reference
sys/dev/extres/syscon/syscon_power.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2020 Jessica Clarke <jrtc27@FreeBSD.org>
      *
      * 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.
     */
    
    /*
     * Driver for simple syscon poweroff and reset devices. The device tree
     * specifications are fully described at:
     *
     * https://www.kernel.org/doc/Documentation/devicetree/bindings/power/reset/syscon-poweroff.txt
     * https://www.kernel.org/doc/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/bus.h>
    #include <sys/types.h>
    #include <sys/eventhandler.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/reboot.h>
    
    #include <machine/bus.h>
    
    #include <dev/ofw/ofw_bus.h>
    #include <dev/ofw/ofw_bus_subr.h>
    #include <dev/ofw/openfirm.h>
    
    #include "syscon_if.h"
    #include "syscon.h"
    
    struct syscon_power_softc {
            struct syscon           *regmap;
            uint32_t                offset;
            uint32_t                value;
            uint32_t                mask;
            bool                    reboot;
            eventhandler_tag        shutdown_tag;
    };
    
    static void
    syscon_power_shutdown_final(device_t dev, int howto)
    {
            struct syscon_power_softc *sc;
            bool write;
    
            sc = device_get_softc(dev);
            if (sc->reboot)
                    write = (howto & RB_HALT) == 0;
            else
                    write = (howto & RB_POWEROFF) != 0;
    
            if (write)
                    SYSCON_MODIFY_4(sc->regmap, sc->offset, sc->mask,
                        sc->value & sc->mask);
    }
    
    static int
    syscon_power_probe(device_t dev)
    {
    
            if (!ofw_bus_status_okay(dev))
                    return (ENXIO);
    
            if (ofw_bus_is_compatible(dev, "syscon-poweroff")) {
                    device_set_desc(dev, "Syscon poweroff");
                    return (BUS_PROBE_DEFAULT);
            } else if (ofw_bus_is_compatible(dev, "syscon-reboot")) {
                    device_set_desc(dev, "Syscon reboot");
                    return (BUS_PROBE_DEFAULT);
            }
    
            return (ENXIO);
    }
    
   static int
   syscon_power_attach(device_t dev)
   {
           struct syscon_power_softc *sc;
           phandle_t node;
           int error, len;
           bool has_mask;
   
           sc = device_get_softc(dev);
           node = ofw_bus_get_node(dev);
   
           if (!OF_hasprop(node, "regmap")) {
                   device_printf(dev, "could not find regmap\n");
                   return (ENXIO);
           }
   
           error = syscon_get_by_ofw_property(dev, node, "regmap", &sc->regmap);
           if (error != 0) {
                   device_printf(dev, "could not get syscon\n");
                   return (ENXIO);
           }
   
           len = OF_getproplen(node, "offset");
           if (len != 4) {
                   device_printf(dev, "could not get offset\n");
                   return (ENXIO);
           }
   
           OF_getencprop(node, "offset", &sc->offset, sizeof(sc->offset));
   
           /* Optional mask */
           has_mask = OF_hasprop(node, "mask");
           if (has_mask) {
                   len = OF_getproplen(node, "mask");
                   if (len != 4) {
                           device_printf(dev, "cannot handle mask\n");
                           return (ENXIO);
                   }
   
                   OF_getencprop(node, "mask", &sc->mask, sizeof(sc->mask));
           } else {
                   sc->mask = 0xffffffff;
           }
   
           /*
            * From the device tree specification:
            *
            *   Legacy usage: If a node doesn't contain a value property but
            *   contains a mask property, the mask property is used as the value.
            */
           if (!OF_hasprop(node, "value")) {
                   if (!has_mask) {
                           device_printf(dev, "must have a value or a mask\n");
                           return (ENXIO);
                   }
   
                   sc->value = sc->mask;
           } else {
                   len = OF_getproplen(node, "value");
                   if (len != 4) {
                           device_printf(dev, "cannot handle value\n");
                           return (ENXIO);
                   }
   
                   OF_getencprop(node, "value", &sc->value, sizeof(sc->value));
           }
   
           sc->reboot = ofw_bus_is_compatible(dev, "syscon-reboot");
           sc->shutdown_tag = EVENTHANDLER_REGISTER(shutdown_final,
               syscon_power_shutdown_final, dev, SHUTDOWN_PRI_LAST);
   
           return (0);
   }
   
   static int
   syscon_power_detach(device_t dev)
   {
           struct syscon_power_softc *sc;
   
           sc = device_get_softc(dev);
           EVENTHANDLER_DEREGISTER(shutdown_final, sc->shutdown_tag);
   
           return (0);
   }
   
   static device_method_t syscon_power_methods[] = {
           DEVMETHOD(device_probe,         syscon_power_probe),
           DEVMETHOD(device_attach,        syscon_power_attach),
           DEVMETHOD(device_detach,        syscon_power_detach),
   
           DEVMETHOD_END
   };
   
   DEFINE_CLASS_0(syscon_power, syscon_power_driver, syscon_power_methods,
       sizeof(struct syscon_power_softc));
   
   DRIVER_MODULE(syscon_power, simplebus, syscon_power_driver, NULL, NULL);

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