FreeBSD/Linux Kernel Cross Reference
sys/powerpc/powermac/tbgpio.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2021 Brandon Bergren <bdragon@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.
     */
    
    #include <sys/cdefs.h>
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/bus.h>
    
    #include <dev/ofw/ofw_bus.h>
    #include <dev/ofw/openfirm.h>
    
    #include <powerpc/powermac/macgpiovar.h>
    #include <powerpc/powermac/platform_powermac.h>
    
    static int      tbgpio_probe(device_t);
    static int      tbgpio_attach(device_t);
    static void     tbgpio_freeze_timebase(device_t, bool);
    
    static device_method_t  tbgpio_methods[] = {
            /* Device interface */
            DEVMETHOD(device_probe,         tbgpio_probe),
            DEVMETHOD(device_attach,        tbgpio_attach),
            DEVMETHOD_END
    };
    
    struct tbgpio_softc {
            uint32_t        sc_value;
            uint32_t        sc_mask;
    };
    
    static driver_t tbgpio_driver = {
            "tbgpio",
            tbgpio_methods,
            sizeof(struct tbgpio_softc)
    };
    
    EARLY_DRIVER_MODULE(tbgpio, macgpio, tbgpio_driver, 0, 0, BUS_PASS_CPU);
    
    static int
    tbgpio_probe(device_t dev)
    {
            phandle_t node;
            const char *name;
            pcell_t pfunc[32];
            int res;
    
            name = ofw_bus_get_name(dev);
            node = ofw_bus_get_node(dev);
    
            if (strcmp(name, "timebase-enable") != 0)
                    return (ENXIO);
    
            res = OF_getencprop(node, "platform-do-cpu-timebase", pfunc,
                sizeof(pfunc));
            if (res == -1)
                    return (ENXIO);
    
            /*
             * If this doesn't look like a simple gpio_write pfunc,
             * complain about it so we can collect the pfunc.
             */
            if (res != 20 || pfunc[2] != 0x01) {
                    printf("\nUnknown platform function detected!\n");
                    printf("Please send a PR including the following data:\n");
                    printf("===================\n");
                    printf("Func: platform-do-cpu-timebase\n");
                    hexdump(pfunc, res, NULL, HD_OMIT_CHARS);
                    printf("===================\n");
                    return (ENXIO);
            }
    
            device_set_desc(dev, "CPU Timebase Control");
           return (BUS_PROBE_SPECIFIC);
   }
   
   static int
   tbgpio_attach(device_t dev)
   {
           phandle_t node;
           struct tbgpio_softc *sc;
   
           /*
            * Structure of pfunc:
            * pfunc[0]: phandle to /cpus
            * pfunc[1]: flags
            * pfunc[2]: 0x1 == CMD_WRITE_GPIO
            * pfunc[3]: value
            * pfunc[4]: mask
            */
           pcell_t pfunc[5];
   
           sc = device_get_softc(dev);
           node = ofw_bus_get_node(dev);
   
           OF_getencprop(node, "platform-do-cpu-timebase", pfunc, sizeof(pfunc));
   
           sc->sc_value = pfunc[3];
           sc->sc_mask = pfunc[4];
   
           powermac_register_timebase(dev, tbgpio_freeze_timebase);
           return (0);
   }
   
   static void
   tbgpio_freeze_timebase(device_t dev, bool freeze)
   {
           struct tbgpio_softc *sc;
           uint32_t val;
   
           sc = device_get_softc(dev);
   
           val = sc->sc_value;
           if (freeze)
                   val = ~val;
           val &= sc->sc_mask;
   
           macgpio_write(dev, val);
   }

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