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