sys/powerpc/powermac/tbgpio.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause
   3  *
   4  * Copyright (c) 2021 Brandon Bergren <bdragon@FreeBSD.org>
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/kernel.h>
  33 #include <sys/module.h>
  34 #include <sys/bus.h>
  35
  36 #include <dev/ofw/ofw_bus.h>
  37 #include <dev/ofw/openfirm.h>
  38
  39 #include <powerpc/powermac/macgpiovar.h>
  40 #include <powerpc/powermac/platform_powermac.h>
  41
  42 static int      tbgpio_probe(device_t);
  43 static int      tbgpio_attach(device_t);
  44 static void     tbgpio_freeze_timebase(device_t, bool);
  45
  46 static device_method_t  tbgpio_methods[] = {
  47         /* Device interface */
  48         DEVMETHOD(device_probe,         tbgpio_probe),
  49         DEVMETHOD(device_attach,        tbgpio_attach),
  50         DEVMETHOD_END
  51 };
  52
  53 struct tbgpio_softc {
  54         uint32_t        sc_value;
  55         uint32_t        sc_mask;
  56 };
  57
  58 static driver_t tbgpio_driver = {
  59         "tbgpio",
  60         tbgpio_methods,
  61         sizeof(struct tbgpio_softc)
  62 };
  63
  64 EARLY_DRIVER_MODULE(tbgpio, macgpio, tbgpio_driver, 0, 0, BUS_PASS_CPU);
  65
  66 static int
  67 tbgpio_probe(device_t dev)
  68 {
  69         phandle_t node;
  70         const char *name;
  71         pcell_t pfunc[32];
  72         int res;
  73
  74         name = ofw_bus_get_name(dev);
  75         node = ofw_bus_get_node(dev);
  76
  77         if (strcmp(name, "timebase-enable") != 0)
  78                 return (ENXIO);
  79
  80         res = OF_getencprop(node, "platform-do-cpu-timebase", pfunc,
  81             sizeof(pfunc));
  82         if (res == -1)
  83                 return (ENXIO);
  84
  85         /*
  86          * If this doesn't look like a simple gpio_write pfunc,
  87          * complain about it so we can collect the pfunc.
  88          */
  89         if (res != 20 || pfunc[2] != 0x01) {
  90                 printf("\nUnknown platform function detected!\n");
  91                 printf("Please send a PR including the following data:\n");
  92                 printf("===================\n");
  93                 printf("Func: platform-do-cpu-timebase\n");
  94                 hexdump(pfunc, res, NULL, HD_OMIT_CHARS);
  95                 printf("===================\n");
  96                 return (ENXIO);
  97         }
  98
  99         device_set_desc(dev, "CPU Timebase Control");
 100         return (BUS_PROBE_SPECIFIC);
 101 }
 102
 103 static int
 104 tbgpio_attach(device_t dev)
 105 {
 106         phandle_t node;
 107         struct tbgpio_softc *sc;
 108
 109         /*
 110          * Structure of pfunc:
 111          * pfunc[0]: phandle to /cpus
 112          * pfunc[1]: flags
 113          * pfunc[2]: 0x1 == CMD_WRITE_GPIO
 114          * pfunc[3]: value
 115          * pfunc[4]: mask
 116          */
 117         pcell_t pfunc[5];
 118
 119         sc = device_get_softc(dev);
 120         node = ofw_bus_get_node(dev);
 121
 122         OF_getencprop(node, "platform-do-cpu-timebase", pfunc, sizeof(pfunc));
 123
 124         sc->sc_value = pfunc[3];
 125         sc->sc_mask = pfunc[4];
 126
 127         powermac_register_timebase(dev, tbgpio_freeze_timebase);
 128         return (0);
 129 }
 130
 131 static void
 132 tbgpio_freeze_timebase(device_t dev, bool freeze)
 133 {
 134         struct tbgpio_softc *sc;
 135         uint32_t val;
 136
 137         sc = device_get_softc(dev);
 138
 139         val = sc->sc_value;
 140         if (freeze)
 141                 val = ~val;
 142         val &= sc->sc_mask;
 143
 144         macgpio_write(dev, val);
 145 }