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 66 {0, 0} 67 }; 68 69 static driver_t dfs_driver = { 70 "dfs", 71 dfs_methods, 72 sizeof(struct dfs_softc) 73 }; 74 75 static devclass_t dfs_devclass; 76 DRIVER_MODULE(dfs, cpu, dfs_driver, dfs_devclass, 0, 0); 77 78 /* 79 * Bits of the HID1 register to enable DFS. See page 2-24 of "MPC7450 80 * RISC Microprocessor Family Reference Manual", rev. 5. 81 */ 82 83 #define HID1_DFS2 (1UL << 22) 84 #define HID1_DFS4 (1UL << 23) 85 86 static void 87 dfs_identify(driver_t *driver, device_t parent) 88 { 89 uint16_t vers; 90 vers = mfpvr() >> 16; 91 92 /* Check for an MPC 7447A or 7448 CPU */ 93 switch (vers) { 94 case MPC7447A: 95 case MPC7448: 96 break; 97 default: 98 return; 99 } 100 101 /* Make sure we're not being doubly invoked. */ 102 if (device_find_child(parent, "dfs", -1) != NULL) 103 return; 104 105 /* 106 * We attach a child for every CPU since settings need to 107 * be performed on every CPU in the SMP case. 108 */ 109 if (BUS_ADD_CHILD(parent, 10, "dfs", -1) == NULL) 110 device_printf(parent, "add dfs child failed\n"); 111 } 112 113 static int 114 dfs_probe(device_t dev) 115 { 116 if (resource_disabled("dfs", 0)) 117 return (ENXIO); 118 119 device_set_desc(dev, "Dynamic Frequency Switching"); 120 return (0); 121 } 122 123 static int 124 dfs_attach(device_t dev) 125 { 126 struct dfs_softc *sc; 127 uint16_t vers; 128 129 sc = device_get_softc(dev); 130 sc->dev = dev; 131 sc->dfs4 = 0; 132 vers = mfpvr() >> 16; 133 134 /* The 7448 supports divide-by-four as well */ 135 if (vers == MPC7448) 136 sc->dfs4 = 1; 137 138 cpufreq_register(dev); 139 return (0); 140 } 141 142 static int 143 dfs_settings(device_t dev, struct cf_setting *sets, int *count) 144 { 145 struct dfs_softc *sc; 146 int states; 147 148 sc = device_get_softc(dev); 149 states = sc->dfs4 ? 3 : 2; 150 if (sets == NULL || count == NULL) 151 return (EINVAL); 152 if (*count < states) 153 return (E2BIG); 154 155 /* Return a list of valid settings for this driver. */ 156 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * states); 157 158 sets[0].freq = 10000; sets[0].dev = dev; 159 sets[1].freq = 5000; sets[1].dev = dev; 160 if (sc->dfs4) 161 sets[2].freq = 2500; sets[2].dev = dev; 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 } 230 231