1 /*- 2 * Copyright (c) 2009 Nathan Whitehorn 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 19 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 20 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 21 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 22 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 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/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 static devclass_t vcoregpio_devclass; 64 65 DRIVER_MODULE(vcoregpio, macgpio, vcoregpio_driver, vcoregpio_devclass, 0, 0); 66 67 static int 68 vcoregpio_probe(device_t dev) 69 { 70 const char *name = ofw_bus_get_name(dev); 71 72 if (strcmp(name, "cpu-vcore-select") != 0) 73 return (ENXIO); 74 75 device_set_desc(dev, "CPU Core Voltage Control"); 76 return (0); 77 } 78 79 static int 80 vcoregpio_attach(device_t dev) 81 { 82 EVENTHANDLER_REGISTER(cpufreq_pre_change, vcoregpio_pre_change, dev, 83 EVENTHANDLER_PRI_ANY); 84 EVENTHANDLER_REGISTER(cpufreq_post_change, vcoregpio_post_change, dev, 85 EVENTHANDLER_PRI_ANY); 86 87 return (0); 88 } 89 90 static void 91 vcoregpio_pre_change(device_t dev, const struct cf_level *level) 92 { 93 if (level->rel_set[0].freq == 10000 /* max */) { 94 /* 95 * Make sure the CPU voltage is raised before we raise 96 * the clock. 97 */ 98 macgpio_write(dev, GPIO_DDR_OUTPUT | 1); 99 DELAY(1000); 100 } 101 } 102 103 static void 104 vcoregpio_post_change(device_t dev, const struct cf_level *level) 105 { 106 if (level->rel_set[0].freq < 10000 /* max */) { 107 DELAY(1000); 108 /* We are safe to reduce CPU voltage now */ 109 macgpio_write(dev, GPIO_DDR_OUTPUT | 0); 110 } 111 } 112 113