1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2009 Nathan Whitehorn
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 */
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/module.h>
33 #include <sys/bus.h>
34 #include <sys/conf.h>
35 #include <sys/cpu.h>
36 #include <sys/eventhandler.h>
37 #include <sys/kernel.h>
38 #include <sys/sysctl.h>
39
40 #include <dev/ofw/ofw_bus.h>
41 #include <dev/ofw/openfirm.h>
42
43 #include <powerpc/powermac/macgpiovar.h>
44
45 static int vcoregpio_probe(device_t);
46 static int vcoregpio_attach(device_t);
47 static void vcoregpio_pre_change(device_t, const struct cf_level *level);
48 static void vcoregpio_post_change(device_t, const struct cf_level *level);
49
50 static device_method_t vcoregpio_methods[] = {
51 /* Device interface */
52 DEVMETHOD(device_probe, vcoregpio_probe),
53 DEVMETHOD(device_attach, vcoregpio_attach),
54 { 0, 0 },
55 };
56
57 static driver_t vcoregpio_driver = {
58 "vcoregpio",
59 vcoregpio_methods,
60 0
61 };
62
63 DRIVER_MODULE(vcoregpio, macgpio, vcoregpio_driver, 0, 0);
64
65 static int
vcoregpio_probe(device_t dev)66 vcoregpio_probe(device_t dev)
67 {
68 const char *name = ofw_bus_get_name(dev);
69
70 if (strcmp(name, "cpu-vcore-select") != 0)
71 return (ENXIO);
72
73 device_set_desc(dev, "CPU Core Voltage Control");
74 return (0);
75 }
76
77 static int
vcoregpio_attach(device_t dev)78 vcoregpio_attach(device_t dev)
79 {
80 EVENTHANDLER_REGISTER(cpufreq_pre_change, vcoregpio_pre_change, dev,
81 EVENTHANDLER_PRI_ANY);
82 EVENTHANDLER_REGISTER(cpufreq_post_change, vcoregpio_post_change, dev,
83 EVENTHANDLER_PRI_ANY);
84
85 return (0);
86 }
87
88 static void
vcoregpio_pre_change(device_t dev,const struct cf_level * level)89 vcoregpio_pre_change(device_t dev, const struct cf_level *level)
90 {
91 if (level->rel_set[0].freq == 10000 /* max */) {
92 /*
93 * Make sure the CPU voltage is raised before we raise
94 * the clock.
95 */
96 macgpio_write(dev, GPIO_DDR_OUTPUT | 1);
97 DELAY(1000);
98 }
99 }
100
101 static void
vcoregpio_post_change(device_t dev,const struct cf_level * level)102 vcoregpio_post_change(device_t dev, const struct cf_level *level)
103 {
104 if (level->rel_set[0].freq < 10000 /* max */) {
105 DELAY(1000);
106 /* We are safe to reduce CPU voltage now */
107 macgpio_write(dev, GPIO_DDR_OUTPUT | 0);
108 }
109 }
110