1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/module.h> 36 #include <sys/bus.h> 37 #include <sys/conf.h> 38 #include <sys/cpu.h> 39 #include <sys/eventhandler.h> 40 #include <sys/kernel.h> 41 #include <sys/sysctl.h> 42 43 #include <dev/ofw/ofw_bus.h> 44 #include <dev/ofw/openfirm.h> 45 46 #include <powerpc/powermac/macgpiovar.h> 47 48 static int vcoregpio_probe(device_t); 49 static int vcoregpio_attach(device_t); 50 static void vcoregpio_pre_change(device_t, const struct cf_level *level); 51 static void vcoregpio_post_change(device_t, const struct cf_level *level); 52 53 static device_method_t vcoregpio_methods[] = { 54 /* Device interface */ 55 DEVMETHOD(device_probe, vcoregpio_probe), 56 DEVMETHOD(device_attach, vcoregpio_attach), 57 { 0, 0 }, 58 }; 59 60 static driver_t vcoregpio_driver = { 61 "vcoregpio", 62 vcoregpio_methods, 63 0 64 }; 65 66 static devclass_t vcoregpio_devclass; 67 68 DRIVER_MODULE(vcoregpio, macgpio, vcoregpio_driver, vcoregpio_devclass, 0, 0); 69 70 static int 71 vcoregpio_probe(device_t dev) 72 { 73 const char *name = ofw_bus_get_name(dev); 74 75 if (strcmp(name, "cpu-vcore-select") != 0) 76 return (ENXIO); 77 78 device_set_desc(dev, "CPU Core Voltage Control"); 79 return (0); 80 } 81 82 static int 83 vcoregpio_attach(device_t dev) 84 { 85 EVENTHANDLER_REGISTER(cpufreq_pre_change, vcoregpio_pre_change, dev, 86 EVENTHANDLER_PRI_ANY); 87 EVENTHANDLER_REGISTER(cpufreq_post_change, vcoregpio_post_change, dev, 88 EVENTHANDLER_PRI_ANY); 89 90 return (0); 91 } 92 93 static void 94 vcoregpio_pre_change(device_t dev, const struct cf_level *level) 95 { 96 if (level->rel_set[0].freq == 10000 /* max */) { 97 /* 98 * Make sure the CPU voltage is raised before we raise 99 * the clock. 100 */ 101 macgpio_write(dev, GPIO_DDR_OUTPUT | 1); 102 DELAY(1000); 103 } 104 } 105 106 static void 107 vcoregpio_post_change(device_t dev, const struct cf_level *level) 108 { 109 if (level->rel_set[0].freq < 10000 /* max */) { 110 DELAY(1000); 111 /* We are safe to reduce CPU voltage now */ 112 macgpio_write(dev, GPIO_DDR_OUTPUT | 0); 113 } 114 } 115