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