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