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 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/bus.h> 35 #include <sys/cpu.h> 36 #include <sys/kernel.h> 37 #include <sys/module.h> 38 39 #include "cpufreq_if.h" 40 41 struct dfs_softc { 42 device_t dev; 43 int dfs4; 44 }; 45 46 static void dfs_identify(driver_t *driver, device_t parent); 47 static int dfs_probe(device_t dev); 48 static int dfs_attach(device_t dev); 49 static int dfs_settings(device_t dev, struct cf_setting *sets, int *count); 50 static int dfs_set(device_t dev, const struct cf_setting *set); 51 static int dfs_get(device_t dev, struct cf_setting *set); 52 static int dfs_type(device_t dev, int *type); 53 54 static device_method_t dfs_methods[] = { 55 /* Device interface */ 56 DEVMETHOD(device_identify, dfs_identify), 57 DEVMETHOD(device_probe, dfs_probe), 58 DEVMETHOD(device_attach, dfs_attach), 59 60 /* cpufreq interface */ 61 DEVMETHOD(cpufreq_drv_set, dfs_set), 62 DEVMETHOD(cpufreq_drv_get, dfs_get), 63 DEVMETHOD(cpufreq_drv_type, dfs_type), 64 DEVMETHOD(cpufreq_drv_settings, dfs_settings), 65 {0, 0} 66 }; 67 68 static driver_t dfs_driver = { 69 "dfs", 70 dfs_methods, 71 sizeof(struct dfs_softc) 72 }; 73 74 static devclass_t dfs_devclass; 75 DRIVER_MODULE(dfs, cpu, dfs_driver, dfs_devclass, 0, 0); 76 77 /* 78 * Bits of the HID1 register to enable DFS. See page 2-24 of "MPC7450 79 * RISC Microprocessor Family Reference Manual", rev. 5. 80 */ 81 82 #define HID1_DFS2 (1UL << 22) 83 #define HID1_DFS4 (1UL << 23) 84 85 static void 86 dfs_identify(driver_t *driver, device_t parent) 87 { 88 uint16_t vers; 89 vers = mfpvr() >> 16; 90 91 /* Check for an MPC 7447A or 7448 CPU */ 92 switch (vers) { 93 case MPC7447A: 94 case MPC7448: 95 break; 96 default: 97 return; 98 } 99 100 /* Make sure we're not being doubly invoked. */ 101 if (device_find_child(parent, "dfs", -1) != NULL) 102 return; 103 104 /* 105 * We attach a child for every CPU since settings need to 106 * be performed on every CPU in the SMP case. 107 */ 108 if (BUS_ADD_CHILD(parent, 10, "dfs", -1) == NULL) 109 device_printf(parent, "add dfs child failed\n"); 110 } 111 112 static int 113 dfs_probe(device_t dev) 114 { 115 if (resource_disabled("dfs", 0)) 116 return (ENXIO); 117 118 device_set_desc(dev, "Dynamic Frequency Switching"); 119 return (0); 120 } 121 122 static int 123 dfs_attach(device_t dev) 124 { 125 struct dfs_softc *sc; 126 uint16_t vers; 127 128 sc = device_get_softc(dev); 129 sc->dev = dev; 130 sc->dfs4 = 0; 131 vers = mfpvr() >> 16; 132 133 /* The 7448 supports divide-by-four as well */ 134 if (vers == MPC7448) 135 sc->dfs4 = 1; 136 137 cpufreq_register(dev); 138 return (0); 139 } 140 141 static int 142 dfs_settings(device_t dev, struct cf_setting *sets, int *count) 143 { 144 struct dfs_softc *sc; 145 int states; 146 147 sc = device_get_softc(dev); 148 states = sc->dfs4 ? 3 : 2; 149 if (sets == NULL || count == NULL) 150 return (EINVAL); 151 if (*count < states) 152 return (E2BIG); 153 154 /* Return a list of valid settings for this driver. */ 155 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * states); 156 157 sets[0].freq = 10000; sets[0].dev = dev; 158 sets[1].freq = 5000; sets[1].dev = dev; 159 if (sc->dfs4) { 160 sets[2].freq = 2500; 161 sets[2].dev = dev; 162 } 163 *count = states; 164 165 return (0); 166 } 167 168 static int 169 dfs_set(device_t dev, const struct cf_setting *set) 170 { 171 register_t hid1; 172 173 if (set == NULL) 174 return (EINVAL); 175 176 hid1 = mfspr(SPR_HID1); 177 hid1 &= ~(HID1_DFS2 | HID1_DFS4); 178 179 if (set->freq == 5000) 180 hid1 |= HID1_DFS2; 181 else if (set->freq == 2500) 182 hid1 |= HID1_DFS4; 183 184 /* 185 * Now set the HID1 register with new values. Calling sequence 186 * taken from page 2-26 of the MPC7450 family CPU manual. 187 */ 188 189 powerpc_sync(); 190 mtspr(SPR_HID1, hid1); 191 powerpc_sync(); isync(); 192 193 return (0); 194 } 195 196 static int 197 dfs_get(device_t dev, struct cf_setting *set) 198 { 199 struct dfs_softc *sc; 200 register_t hid1; 201 202 if (set == NULL) 203 return (EINVAL); 204 sc = device_get_softc(dev); 205 206 memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set)); 207 208 hid1 = mfspr(SPR_HID1); 209 210 set->freq = 10000; 211 if (hid1 & HID1_DFS2) 212 set->freq = 5000; 213 else if (sc->dfs4 && (hid1 & HID1_DFS4)) 214 set->freq = 2500; 215 216 set->dev = dev; 217 218 return (0); 219 } 220 221 static int 222 dfs_type(device_t dev, int *type) 223 { 224 225 if (type == NULL) 226 return (EINVAL); 227 228 *type = CPUFREQ_TYPE_RELATIVE; 229 return (0); 230 } 231