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