1 /* 2 * This file provides the ACPI based P-state support. This 3 * module works with generic cpufreq infrastructure. Most of 4 * the code is based on i386 version 5 * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c) 6 * 7 * Copyright (C) 2005 Intel Corp 8 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/slab.h> 13 #include <linux/module.h> 14 #include <linux/init.h> 15 #include <linux/cpufreq.h> 16 #include <linux/proc_fs.h> 17 #include <linux/seq_file.h> 18 #include <asm/io.h> 19 #include <asm/uaccess.h> 20 #include <asm/pal.h> 21 22 #include <linux/acpi.h> 23 #include <acpi/processor.h> 24 25 MODULE_AUTHOR("Venkatesh Pallipadi"); 26 MODULE_DESCRIPTION("ACPI Processor P-States Driver"); 27 MODULE_LICENSE("GPL"); 28 29 30 struct cpufreq_acpi_io { 31 struct acpi_processor_performance acpi_data; 32 struct cpufreq_frequency_table *freq_table; 33 unsigned int resume; 34 }; 35 36 static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS]; 37 38 static struct cpufreq_driver acpi_cpufreq_driver; 39 40 41 static int 42 processor_set_pstate ( 43 u32 value) 44 { 45 s64 retval; 46 47 pr_debug("processor_set_pstate\n"); 48 49 retval = ia64_pal_set_pstate((u64)value); 50 51 if (retval) { 52 pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n", 53 value, retval); 54 return -ENODEV; 55 } 56 return (int)retval; 57 } 58 59 60 static int 61 processor_get_pstate ( 62 u32 *value) 63 { 64 u64 pstate_index = 0; 65 s64 retval; 66 67 pr_debug("processor_get_pstate\n"); 68 69 retval = ia64_pal_get_pstate(&pstate_index, 70 PAL_GET_PSTATE_TYPE_INSTANT); 71 *value = (u32) pstate_index; 72 73 if (retval) 74 pr_debug("Failed to get current freq with " 75 "error 0x%lx, idx 0x%x\n", retval, *value); 76 77 return (int)retval; 78 } 79 80 81 /* To be used only after data->acpi_data is initialized */ 82 static unsigned 83 extract_clock ( 84 struct cpufreq_acpi_io *data, 85 unsigned value, 86 unsigned int cpu) 87 { 88 unsigned long i; 89 90 pr_debug("extract_clock\n"); 91 92 for (i = 0; i < data->acpi_data.state_count; i++) { 93 if (value == data->acpi_data.states[i].status) 94 return data->acpi_data.states[i].core_frequency; 95 } 96 return data->acpi_data.states[i-1].core_frequency; 97 } 98 99 100 static unsigned int 101 processor_get_freq ( 102 struct cpufreq_acpi_io *data, 103 unsigned int cpu) 104 { 105 int ret = 0; 106 u32 value = 0; 107 cpumask_t saved_mask; 108 unsigned long clock_freq; 109 110 pr_debug("processor_get_freq\n"); 111 112 saved_mask = current->cpus_allowed; 113 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 114 if (smp_processor_id() != cpu) 115 goto migrate_end; 116 117 /* processor_get_pstate gets the instantaneous frequency */ 118 ret = processor_get_pstate(&value); 119 120 if (ret) { 121 set_cpus_allowed_ptr(current, &saved_mask); 122 printk(KERN_WARNING "get performance failed with error %d\n", 123 ret); 124 ret = 0; 125 goto migrate_end; 126 } 127 clock_freq = extract_clock(data, value, cpu); 128 ret = (clock_freq*1000); 129 130 migrate_end: 131 set_cpus_allowed_ptr(current, &saved_mask); 132 return ret; 133 } 134 135 136 static int 137 processor_set_freq ( 138 struct cpufreq_acpi_io *data, 139 struct cpufreq_policy *policy, 140 int state) 141 { 142 int ret = 0; 143 u32 value = 0; 144 struct cpufreq_freqs cpufreq_freqs; 145 cpumask_t saved_mask; 146 int retval; 147 148 pr_debug("processor_set_freq\n"); 149 150 saved_mask = current->cpus_allowed; 151 set_cpus_allowed_ptr(current, cpumask_of(policy->cpu)); 152 if (smp_processor_id() != policy->cpu) { 153 retval = -EAGAIN; 154 goto migrate_end; 155 } 156 157 if (state == data->acpi_data.state) { 158 if (unlikely(data->resume)) { 159 pr_debug("Called after resume, resetting to P%d\n", state); 160 data->resume = 0; 161 } else { 162 pr_debug("Already at target state (P%d)\n", state); 163 retval = 0; 164 goto migrate_end; 165 } 166 } 167 168 pr_debug("Transitioning from P%d to P%d\n", 169 data->acpi_data.state, state); 170 171 /* cpufreq frequency struct */ 172 cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency; 173 cpufreq_freqs.new = data->freq_table[state].frequency; 174 175 /* notify cpufreq */ 176 cpufreq_notify_transition(policy, &cpufreq_freqs, CPUFREQ_PRECHANGE); 177 178 /* 179 * First we write the target state's 'control' value to the 180 * control_register. 181 */ 182 183 value = (u32) data->acpi_data.states[state].control; 184 185 pr_debug("Transitioning to state: 0x%08x\n", value); 186 187 ret = processor_set_pstate(value); 188 if (ret) { 189 unsigned int tmp = cpufreq_freqs.new; 190 cpufreq_notify_transition(policy, &cpufreq_freqs, 191 CPUFREQ_POSTCHANGE); 192 cpufreq_freqs.new = cpufreq_freqs.old; 193 cpufreq_freqs.old = tmp; 194 cpufreq_notify_transition(policy, &cpufreq_freqs, 195 CPUFREQ_PRECHANGE); 196 cpufreq_notify_transition(policy, &cpufreq_freqs, 197 CPUFREQ_POSTCHANGE); 198 printk(KERN_WARNING "Transition failed with error %d\n", ret); 199 retval = -ENODEV; 200 goto migrate_end; 201 } 202 203 cpufreq_notify_transition(policy, &cpufreq_freqs, CPUFREQ_POSTCHANGE); 204 205 data->acpi_data.state = state; 206 207 retval = 0; 208 209 migrate_end: 210 set_cpus_allowed_ptr(current, &saved_mask); 211 return (retval); 212 } 213 214 215 static unsigned int 216 acpi_cpufreq_get ( 217 unsigned int cpu) 218 { 219 struct cpufreq_acpi_io *data = acpi_io_data[cpu]; 220 221 pr_debug("acpi_cpufreq_get\n"); 222 223 return processor_get_freq(data, cpu); 224 } 225 226 227 static int 228 acpi_cpufreq_target ( 229 struct cpufreq_policy *policy, 230 unsigned int target_freq, 231 unsigned int relation) 232 { 233 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu]; 234 unsigned int next_state = 0; 235 unsigned int result = 0; 236 237 pr_debug("acpi_cpufreq_setpolicy\n"); 238 239 result = cpufreq_frequency_table_target(policy, 240 data->freq_table, target_freq, relation, &next_state); 241 if (result) 242 return (result); 243 244 result = processor_set_freq(data, policy, next_state); 245 246 return (result); 247 } 248 249 250 static int 251 acpi_cpufreq_verify ( 252 struct cpufreq_policy *policy) 253 { 254 unsigned int result = 0; 255 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu]; 256 257 pr_debug("acpi_cpufreq_verify\n"); 258 259 result = cpufreq_frequency_table_verify(policy, 260 data->freq_table); 261 262 return (result); 263 } 264 265 266 static int 267 acpi_cpufreq_cpu_init ( 268 struct cpufreq_policy *policy) 269 { 270 unsigned int i; 271 unsigned int cpu = policy->cpu; 272 struct cpufreq_acpi_io *data; 273 unsigned int result = 0; 274 275 pr_debug("acpi_cpufreq_cpu_init\n"); 276 277 data = kzalloc(sizeof(*data), GFP_KERNEL); 278 if (!data) 279 return (-ENOMEM); 280 281 acpi_io_data[cpu] = data; 282 283 result = acpi_processor_register_performance(&data->acpi_data, cpu); 284 285 if (result) 286 goto err_free; 287 288 /* capability check */ 289 if (data->acpi_data.state_count <= 1) { 290 pr_debug("No P-States\n"); 291 result = -ENODEV; 292 goto err_unreg; 293 } 294 295 if ((data->acpi_data.control_register.space_id != 296 ACPI_ADR_SPACE_FIXED_HARDWARE) || 297 (data->acpi_data.status_register.space_id != 298 ACPI_ADR_SPACE_FIXED_HARDWARE)) { 299 pr_debug("Unsupported address space [%d, %d]\n", 300 (u32) (data->acpi_data.control_register.space_id), 301 (u32) (data->acpi_data.status_register.space_id)); 302 result = -ENODEV; 303 goto err_unreg; 304 } 305 306 /* alloc freq_table */ 307 data->freq_table = kmalloc(sizeof(*data->freq_table) * 308 (data->acpi_data.state_count + 1), 309 GFP_KERNEL); 310 if (!data->freq_table) { 311 result = -ENOMEM; 312 goto err_unreg; 313 } 314 315 /* detect transition latency */ 316 policy->cpuinfo.transition_latency = 0; 317 for (i=0; i<data->acpi_data.state_count; i++) { 318 if ((data->acpi_data.states[i].transition_latency * 1000) > 319 policy->cpuinfo.transition_latency) { 320 policy->cpuinfo.transition_latency = 321 data->acpi_data.states[i].transition_latency * 1000; 322 } 323 } 324 policy->cur = processor_get_freq(data, policy->cpu); 325 326 /* table init */ 327 for (i = 0; i <= data->acpi_data.state_count; i++) 328 { 329 data->freq_table[i].driver_data = i; 330 if (i < data->acpi_data.state_count) { 331 data->freq_table[i].frequency = 332 data->acpi_data.states[i].core_frequency * 1000; 333 } else { 334 data->freq_table[i].frequency = CPUFREQ_TABLE_END; 335 } 336 } 337 338 result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table); 339 if (result) { 340 goto err_freqfree; 341 } 342 343 /* notify BIOS that we exist */ 344 acpi_processor_notify_smm(THIS_MODULE); 345 346 printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management " 347 "activated.\n", cpu); 348 349 for (i = 0; i < data->acpi_data.state_count; i++) 350 pr_debug(" %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n", 351 (i == data->acpi_data.state?'*':' '), i, 352 (u32) data->acpi_data.states[i].core_frequency, 353 (u32) data->acpi_data.states[i].power, 354 (u32) data->acpi_data.states[i].transition_latency, 355 (u32) data->acpi_data.states[i].bus_master_latency, 356 (u32) data->acpi_data.states[i].status, 357 (u32) data->acpi_data.states[i].control); 358 359 cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu); 360 361 /* the first call to ->target() should result in us actually 362 * writing something to the appropriate registers. */ 363 data->resume = 1; 364 365 return (result); 366 367 err_freqfree: 368 kfree(data->freq_table); 369 err_unreg: 370 acpi_processor_unregister_performance(&data->acpi_data, cpu); 371 err_free: 372 kfree(data); 373 acpi_io_data[cpu] = NULL; 374 375 return (result); 376 } 377 378 379 static int 380 acpi_cpufreq_cpu_exit ( 381 struct cpufreq_policy *policy) 382 { 383 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu]; 384 385 pr_debug("acpi_cpufreq_cpu_exit\n"); 386 387 if (data) { 388 cpufreq_frequency_table_put_attr(policy->cpu); 389 acpi_io_data[policy->cpu] = NULL; 390 acpi_processor_unregister_performance(&data->acpi_data, 391 policy->cpu); 392 kfree(data); 393 } 394 395 return (0); 396 } 397 398 399 static struct freq_attr* acpi_cpufreq_attr[] = { 400 &cpufreq_freq_attr_scaling_available_freqs, 401 NULL, 402 }; 403 404 405 static struct cpufreq_driver acpi_cpufreq_driver = { 406 .verify = acpi_cpufreq_verify, 407 .target = acpi_cpufreq_target, 408 .get = acpi_cpufreq_get, 409 .init = acpi_cpufreq_cpu_init, 410 .exit = acpi_cpufreq_cpu_exit, 411 .name = "acpi-cpufreq", 412 .attr = acpi_cpufreq_attr, 413 }; 414 415 416 static int __init 417 acpi_cpufreq_init (void) 418 { 419 pr_debug("acpi_cpufreq_init\n"); 420 421 return cpufreq_register_driver(&acpi_cpufreq_driver); 422 } 423 424 425 static void __exit 426 acpi_cpufreq_exit (void) 427 { 428 pr_debug("acpi_cpufreq_exit\n"); 429 430 cpufreq_unregister_driver(&acpi_cpufreq_driver); 431 return; 432 } 433 434 435 late_initcall(acpi_cpufreq_init); 436 module_exit(acpi_cpufreq_exit); 437 438