1 /* 2 * processor_thermal.c - Passive cooling submodule of the ACPI processor driver 3 * 4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com> 5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> 6 * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de> 7 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> 8 * - Added processor hotplug support 9 * 10 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License as published by 14 * the Free Software Foundation; either version 2 of the License, or (at 15 * your option) any later version. 16 * 17 * This program is distributed in the hope that it will be useful, but 18 * WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 20 * General Public License for more details. 21 * 22 * You should have received a copy of the GNU General Public License along 23 * with this program; if not, write to the Free Software Foundation, Inc., 24 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. 25 * 26 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 27 */ 28 29 #include <linux/kernel.h> 30 #include <linux/module.h> 31 #include <linux/init.h> 32 #include <linux/cpufreq.h> 33 34 #include <asm/uaccess.h> 35 36 #include <acpi/acpi_bus.h> 37 #include <acpi/processor.h> 38 #include <acpi/acpi_drivers.h> 39 40 #define PREFIX "ACPI: " 41 42 #define ACPI_PROCESSOR_CLASS "processor" 43 #define _COMPONENT ACPI_PROCESSOR_COMPONENT 44 ACPI_MODULE_NAME("processor_thermal"); 45 46 #ifdef CONFIG_CPU_FREQ 47 48 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it 49 * offers (in most cases) voltage scaling in addition to frequency scaling, and 50 * thus a cubic (instead of linear) reduction of energy. Also, we allow for 51 * _any_ cpufreq driver and not only the acpi-cpufreq driver. 52 */ 53 54 #define CPUFREQ_THERMAL_MIN_STEP 0 55 #define CPUFREQ_THERMAL_MAX_STEP 3 56 57 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg); 58 static unsigned int acpi_thermal_cpufreq_is_init = 0; 59 60 #define reduction_pctg(cpu) \ 61 per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu)) 62 63 /* 64 * Emulate "per package data" using per cpu data (which should really be 65 * provided elsewhere) 66 * 67 * Note we can lose a CPU on cpu hotunplug, in this case we forget the state 68 * temporarily. Fortunately that's not a big issue here (I hope) 69 */ 70 static int phys_package_first_cpu(int cpu) 71 { 72 int i; 73 int id = topology_physical_package_id(cpu); 74 75 for_each_online_cpu(i) 76 if (topology_physical_package_id(i) == id) 77 return i; 78 return 0; 79 } 80 81 static int cpu_has_cpufreq(unsigned int cpu) 82 { 83 struct cpufreq_policy policy; 84 if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu)) 85 return 0; 86 return 1; 87 } 88 89 static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb, 90 unsigned long event, void *data) 91 { 92 struct cpufreq_policy *policy = data; 93 unsigned long max_freq = 0; 94 95 if (event != CPUFREQ_ADJUST) 96 goto out; 97 98 max_freq = ( 99 policy->cpuinfo.max_freq * 100 (100 - reduction_pctg(policy->cpu) * 20) 101 ) / 100; 102 103 cpufreq_verify_within_limits(policy, 0, max_freq); 104 105 out: 106 return 0; 107 } 108 109 static struct notifier_block acpi_thermal_cpufreq_notifier_block = { 110 .notifier_call = acpi_thermal_cpufreq_notifier, 111 }; 112 113 static int cpufreq_get_max_state(unsigned int cpu) 114 { 115 if (!cpu_has_cpufreq(cpu)) 116 return 0; 117 118 return CPUFREQ_THERMAL_MAX_STEP; 119 } 120 121 static int cpufreq_get_cur_state(unsigned int cpu) 122 { 123 if (!cpu_has_cpufreq(cpu)) 124 return 0; 125 126 return reduction_pctg(cpu); 127 } 128 129 static int cpufreq_set_cur_state(unsigned int cpu, int state) 130 { 131 int i; 132 133 if (!cpu_has_cpufreq(cpu)) 134 return 0; 135 136 reduction_pctg(cpu) = state; 137 138 /* 139 * Update all the CPUs in the same package because they all 140 * contribute to the temperature and often share the same 141 * frequency. 142 */ 143 for_each_online_cpu(i) { 144 if (topology_physical_package_id(i) == 145 topology_physical_package_id(cpu)) 146 cpufreq_update_policy(i); 147 } 148 return 0; 149 } 150 151 void acpi_thermal_cpufreq_init(void) 152 { 153 int i; 154 155 i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block, 156 CPUFREQ_POLICY_NOTIFIER); 157 if (!i) 158 acpi_thermal_cpufreq_is_init = 1; 159 } 160 161 void acpi_thermal_cpufreq_exit(void) 162 { 163 if (acpi_thermal_cpufreq_is_init) 164 cpufreq_unregister_notifier 165 (&acpi_thermal_cpufreq_notifier_block, 166 CPUFREQ_POLICY_NOTIFIER); 167 168 acpi_thermal_cpufreq_is_init = 0; 169 } 170 171 #else /* ! CONFIG_CPU_FREQ */ 172 static int cpufreq_get_max_state(unsigned int cpu) 173 { 174 return 0; 175 } 176 177 static int cpufreq_get_cur_state(unsigned int cpu) 178 { 179 return 0; 180 } 181 182 static int cpufreq_set_cur_state(unsigned int cpu, int state) 183 { 184 return 0; 185 } 186 187 #endif 188 189 /* thermal coolign device callbacks */ 190 static int acpi_processor_max_state(struct acpi_processor *pr) 191 { 192 int max_state = 0; 193 194 /* 195 * There exists four states according to 196 * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3 197 */ 198 max_state += cpufreq_get_max_state(pr->id); 199 if (pr->flags.throttling) 200 max_state += (pr->throttling.state_count -1); 201 202 return max_state; 203 } 204 static int 205 processor_get_max_state(struct thermal_cooling_device *cdev, 206 unsigned long *state) 207 { 208 struct acpi_device *device = cdev->devdata; 209 struct acpi_processor *pr; 210 211 if (!device) 212 return -EINVAL; 213 214 pr = acpi_driver_data(device); 215 if (!pr) 216 return -EINVAL; 217 218 *state = acpi_processor_max_state(pr); 219 return 0; 220 } 221 222 static int 223 processor_get_cur_state(struct thermal_cooling_device *cdev, 224 unsigned long *cur_state) 225 { 226 struct acpi_device *device = cdev->devdata; 227 struct acpi_processor *pr; 228 229 if (!device) 230 return -EINVAL; 231 232 pr = acpi_driver_data(device); 233 if (!pr) 234 return -EINVAL; 235 236 *cur_state = cpufreq_get_cur_state(pr->id); 237 if (pr->flags.throttling) 238 *cur_state += pr->throttling.state; 239 return 0; 240 } 241 242 static int 243 processor_set_cur_state(struct thermal_cooling_device *cdev, 244 unsigned long state) 245 { 246 struct acpi_device *device = cdev->devdata; 247 struct acpi_processor *pr; 248 int result = 0; 249 int max_pstate; 250 251 if (!device) 252 return -EINVAL; 253 254 pr = acpi_driver_data(device); 255 if (!pr) 256 return -EINVAL; 257 258 max_pstate = cpufreq_get_max_state(pr->id); 259 260 if (state > acpi_processor_max_state(pr)) 261 return -EINVAL; 262 263 if (state <= max_pstate) { 264 if (pr->flags.throttling && pr->throttling.state) 265 result = acpi_processor_set_throttling(pr, 0, false); 266 cpufreq_set_cur_state(pr->id, state); 267 } else { 268 cpufreq_set_cur_state(pr->id, max_pstate); 269 result = acpi_processor_set_throttling(pr, 270 state - max_pstate, false); 271 } 272 return result; 273 } 274 275 const struct thermal_cooling_device_ops processor_cooling_ops = { 276 .get_max_state = processor_get_max_state, 277 .get_cur_state = processor_get_cur_state, 278 .set_cur_state = processor_set_cur_state, 279 }; 280