pcr.c revision 208150
1/*- 2 * Copyright (c) 2009 Nathan Whitehorn 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 19 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 20 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 21 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 22 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: head/sys/powerpc/cpufreq/pcr.c 208150 2010-05-16 15:21:13Z nwhitehorn $"); 29 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 <dev/ofw/ofw_bus.h> 38 39#include "cpufreq_if.h" 40 41struct pcr_softc { 42 device_t dev; 43 uint32_t pcr_vals[3]; 44 int nmodes; 45}; 46 47static void pcr_identify(driver_t *driver, device_t parent); 48static int pcr_probe(device_t dev); 49static int pcr_attach(device_t dev); 50static int pcr_settings(device_t dev, struct cf_setting *sets, int *count); 51static int pcr_set(device_t dev, const struct cf_setting *set); 52static int pcr_get(device_t dev, struct cf_setting *set); 53static int pcr_type(device_t dev, int *type); 54 55static device_method_t pcr_methods[] = { 56 /* Device interface */ 57 DEVMETHOD(device_identify, pcr_identify), 58 DEVMETHOD(device_probe, pcr_probe), 59 DEVMETHOD(device_attach, pcr_attach), 60 61 /* cpufreq interface */ 62 DEVMETHOD(cpufreq_drv_set, pcr_set), 63 DEVMETHOD(cpufreq_drv_get, pcr_get), 64 DEVMETHOD(cpufreq_drv_type, pcr_type), 65 DEVMETHOD(cpufreq_drv_settings, pcr_settings), 66 67 {0, 0} 68}; 69 70static driver_t pcr_driver = { 71 "pcr", 72 pcr_methods, 73 sizeof(struct pcr_softc) 74}; 75 76static devclass_t pcr_devclass; 77DRIVER_MODULE(pcr, cpu, pcr_driver, pcr_devclass, 0, 0); 78 79/* 80 * States 81 */ 82 83#define PCR_TO_FREQ(a) ((a >> 17) & 3) 84 85#define PCR_FULL 0 86#define PCR_HALF 1 87#define PCR_QUARTER 2 /* Only on 970MP */ 88 89#define PSR_RECEIVED (1ULL << 61) 90#define PSR_COMPLETED (1ULL << 61) 91 92/* 93 * SCOM addresses 94 */ 95 96#define SCOM_PCR 0x0aa00100 /* Power Control Register */ 97#define SCOM_PCR_BIT 0x80000000 /* Data bit for PCR */ 98#define SCOM_PSR 0x40800100 /* Power Status Register */ 99 100/* 101 * SCOM Glue 102 */ 103 104#define SCOMC_READ 0x00008000 105#define SCOMC_WRITE 0x00000000 106 107static void 108write_scom(register_t address, uint64_t value) 109{ 110 register_t msr; 111 register_t hi, lo, scratch; 112 113 hi = (value >> 32) & 0xffffffff; 114 lo = value & 0xffffffff; 115 116 msr = mfmsr(); 117 mtmsr(msr & ~PSL_EE); isync(); 118 119 mtspr64(SPR_SCOMD, hi, lo, scratch); 120 isync(); 121 mtspr(SPR_SCOMC, address | SCOMC_WRITE); 122 isync(); 123 124 mtmsr(msr); isync(); 125} 126 127static uint64_t 128read_scom(register_t address) 129{ 130 register_t msr; 131 uint64_t ret; 132 133 msr = mfmsr(); 134 mtmsr(msr & ~PSL_EE); isync(); 135 136 mtspr(SPR_SCOMC, address | SCOMC_READ); 137 isync(); 138 139 __asm __volatile ("mfspr %0,%1;" 140 " mr %0+1, %0; srdi %0,%0,32" : "=r" (ret) : "K" (SPR_SCOMD)); 141 142 (void)mfspr(SPR_SCOMC); /* Complete transcation */ 143 144 mtmsr(msr); isync(); 145 146 return (ret); 147} 148 149static void 150pcr_identify(driver_t *driver, device_t parent) 151{ 152 uint16_t vers; 153 vers = mfpvr() >> 16; 154 155 /* Check for an IBM 970-class CPU */ 156 switch (vers) { 157 case IBM970FX: 158 case IBM970GX: 159 case IBM970MP: 160 break; 161 default: 162 return; 163 } 164 165 /* Make sure we're not being doubly invoked. */ 166 if (device_find_child(parent, "pcr", -1) != NULL) 167 return; 168 169 /* 170 * We attach a child for every CPU since settings need to 171 * be performed on every CPU in the SMP case. 172 */ 173 if (BUS_ADD_CHILD(parent, 10, "pcr", -1) == NULL) 174 device_printf(parent, "add pcr child failed\n"); 175} 176 177static int 178pcr_probe(device_t dev) 179{ 180 if (resource_disabled("pcr", 0)) 181 return (ENXIO); 182 183 device_set_desc(dev, "PPC 970 Power Control Register"); 184 return (0); 185} 186 187static int 188pcr_attach(device_t dev) 189{ 190 struct pcr_softc *sc; 191 phandle_t cpu; 192 uint32_t modes[3]; 193 int i; 194 195 sc = device_get_softc(dev); 196 sc->dev = dev; 197 198 cpu = ofw_bus_get_node(device_get_parent(dev)); 199 200 if (cpu <= 0) { 201 device_printf(dev,"No CPU device tree node!\n"); 202 return (ENXIO); 203 } 204 205 if (OF_getproplen(cpu, "power-mode-data") <= 0) { 206 /* Use the first CPU's node */ 207 cpu = OF_child(OF_parent(cpu)); 208 } 209 210 /* 211 * Collect the PCR values for each mode from the device tree. 212 * These include bus timing information, and so cannot be 213 * directly computed. 214 */ 215 sc->nmodes = OF_getproplen(cpu, "power-mode-data"); 216 if (sc->nmodes <= 0 || sc->nmodes > sizeof(sc->pcr_vals)) { 217 device_printf(dev,"No power mode data in device tree!\n"); 218 return (ENXIO); 219 } 220 OF_getprop(cpu, "power-mode-data", modes, sc->nmodes); 221 sc->nmodes /= sizeof(modes[0]); 222 223 /* Sort the modes */ 224 for (i = 0; i < sc->nmodes; i++) 225 sc->pcr_vals[PCR_TO_FREQ(modes[i])] = modes[i]; 226 227 cpufreq_register(dev); 228 return (0); 229} 230 231static int 232pcr_settings(device_t dev, struct cf_setting *sets, int *count) 233{ 234 struct pcr_softc *sc; 235 236 sc = device_get_softc(dev); 237 if (sets == NULL || count == NULL) 238 return (EINVAL); 239 if (*count < sc->nmodes) 240 return (E2BIG); 241 242 /* Return a list of valid settings for this driver. */ 243 memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * sc->nmodes); 244 245 sets[0].freq = 10000; sets[0].dev = dev; 246 sets[1].freq = 5000; sets[1].dev = dev; 247 if (sc->nmodes > 2) 248 sets[2].freq = 2500; sets[2].dev = dev; 249 *count = sc->nmodes; 250 251 return (0); 252} 253 254static int 255pcr_set(device_t dev, const struct cf_setting *set) 256{ 257 struct pcr_softc *sc; 258 register_t pcr, msr; 259 uint64_t psr; 260 261 if (set == NULL) 262 return (EINVAL); 263 sc = device_get_softc(dev); 264 265 /* Construct the new PCR */ 266 267 pcr = SCOM_PCR_BIT; 268 269 if (set->freq == 10000) 270 pcr |= sc->pcr_vals[0]; 271 else if (set->freq == 5000) 272 pcr |= sc->pcr_vals[1]; 273 else if (set->freq == 2500) 274 pcr |= sc->pcr_vals[2]; 275 276 msr = mfmsr(); 277 mtmsr(msr & ~PSL_EE); isync(); 278 279 /* 970MP requires PCR and PCRH to be cleared first */ 280 281 write_scom(SCOM_PCR,0); /* Clear PCRH */ 282 write_scom(SCOM_PCR,SCOM_PCR_BIT); /* Clear PCR */ 283 284 /* Set PCR */ 285 286 write_scom(SCOM_PCR, pcr); 287 288 /* Wait for completion */ 289 290 do { 291 DELAY(100); 292 psr = read_scom(SCOM_PSR); 293 } while ((psr & PSR_RECEIVED) && !(psr & PSR_COMPLETED)); 294 295 mtmsr(msr); isync(); 296 297 return (0); 298} 299 300static int 301pcr_get(device_t dev, struct cf_setting *set) 302{ 303 struct pcr_softc *sc; 304 uint64_t psr; 305 306 if (set == NULL) 307 return (EINVAL); 308 sc = device_get_softc(dev); 309 310 memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set)); 311 312 psr = read_scom(SCOM_PSR); 313 314 /* We want bits 6 and 7 */ 315 psr = (psr >> 56) & 3; 316 317 set->freq = 10000; 318 if (psr == PCR_HALF) 319 set->freq = 5000; 320 else if (psr == PCR_QUARTER) 321 set->freq = 2500; 322 323 set->dev = dev; 324 325 return (0); 326} 327 328static int 329pcr_type(device_t dev, int *type) 330{ 331 332 if (type == NULL) 333 return (EINVAL); 334 335 *type = CPUFREQ_TYPE_RELATIVE; 336 return (0); 337} 338 339