pcc-cpufreq.c revision e71f5cc402ecb42b407ae52add7b173bf1c53daa
1/* 2 * pcc-cpufreq.c - Processor Clocking Control firmware cpufreq interface 3 * 4 * Copyright (C) 2009 Red Hat, Matthew Garrett <mjg@redhat.com> 5 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P. 6 * Nagananda Chumbalkar <nagananda.chumbalkar@hp.com> 7 * 8 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; version 2 of the License. 13 * 14 * This program is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or NON 17 * INFRINGEMENT. See the GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License along 20 * with this program; if not, write to the Free Software Foundation, Inc., 21 * 675 Mass Ave, Cambridge, MA 02139, USA. 22 * 23 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 24 */ 25 26#include <linux/kernel.h> 27#include <linux/module.h> 28#include <linux/init.h> 29#include <linux/smp.h> 30#include <linux/sched.h> 31#include <linux/cpufreq.h> 32#include <linux/compiler.h> 33#include <linux/slab.h> 34 35#include <linux/acpi.h> 36#include <linux/io.h> 37#include <linux/spinlock.h> 38#include <linux/uaccess.h> 39 40#include <acpi/processor.h> 41 42#define PCC_VERSION "1.10.00" 43#define POLL_LOOPS 300 44 45#define CMD_COMPLETE 0x1 46#define CMD_GET_FREQ 0x0 47#define CMD_SET_FREQ 0x1 48 49#define BUF_SZ 4 50 51struct pcc_register_resource { 52 u8 descriptor; 53 u16 length; 54 u8 space_id; 55 u8 bit_width; 56 u8 bit_offset; 57 u8 access_size; 58 u64 address; 59} __attribute__ ((packed)); 60 61struct pcc_memory_resource { 62 u8 descriptor; 63 u16 length; 64 u8 space_id; 65 u8 resource_usage; 66 u8 type_specific; 67 u64 granularity; 68 u64 minimum; 69 u64 maximum; 70 u64 translation_offset; 71 u64 address_length; 72} __attribute__ ((packed)); 73 74static struct cpufreq_driver pcc_cpufreq_driver; 75 76struct pcc_header { 77 u32 signature; 78 u16 length; 79 u8 major; 80 u8 minor; 81 u32 features; 82 u16 command; 83 u16 status; 84 u32 latency; 85 u32 minimum_time; 86 u32 maximum_time; 87 u32 nominal; 88 u32 throttled_frequency; 89 u32 minimum_frequency; 90}; 91 92static void __iomem *pcch_virt_addr; 93static struct pcc_header __iomem *pcch_hdr; 94 95static DEFINE_SPINLOCK(pcc_lock); 96 97static struct acpi_generic_address doorbell; 98 99static u64 doorbell_preserve; 100static u64 doorbell_write; 101 102static u8 OSC_UUID[16] = {0x9F, 0x2C, 0x9B, 0x63, 0x91, 0x70, 0x1f, 0x49, 103 0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46}; 104 105struct pcc_cpu { 106 u32 input_offset; 107 u32 output_offset; 108}; 109 110static struct pcc_cpu __percpu *pcc_cpu_info; 111 112static int pcc_cpufreq_verify(struct cpufreq_policy *policy) 113{ 114 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, 115 policy->cpuinfo.max_freq); 116 return 0; 117} 118 119static inline void pcc_cmd(void) 120{ 121 u64 doorbell_value; 122 int i; 123 124 acpi_read(&doorbell_value, &doorbell); 125 acpi_write((doorbell_value & doorbell_preserve) | doorbell_write, 126 &doorbell); 127 128 for (i = 0; i < POLL_LOOPS; i++) { 129 if (ioread16(&pcch_hdr->status) & CMD_COMPLETE) 130 break; 131 } 132} 133 134static inline void pcc_clear_mapping(void) 135{ 136 if (pcch_virt_addr) 137 iounmap(pcch_virt_addr); 138 pcch_virt_addr = NULL; 139} 140 141static unsigned int pcc_get_freq(unsigned int cpu) 142{ 143 struct pcc_cpu *pcc_cpu_data; 144 unsigned int curr_freq; 145 unsigned int freq_limit; 146 u16 status; 147 u32 input_buffer; 148 u32 output_buffer; 149 150 spin_lock(&pcc_lock); 151 152 pr_debug("get: get_freq for CPU %d\n", cpu); 153 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 154 155 input_buffer = 0x1; 156 iowrite32(input_buffer, 157 (pcch_virt_addr + pcc_cpu_data->input_offset)); 158 iowrite16(CMD_GET_FREQ, &pcch_hdr->command); 159 160 pcc_cmd(); 161 162 output_buffer = 163 ioread32(pcch_virt_addr + pcc_cpu_data->output_offset); 164 165 /* Clear the input buffer - we are done with the current command */ 166 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ); 167 168 status = ioread16(&pcch_hdr->status); 169 if (status != CMD_COMPLETE) { 170 pr_debug("get: FAILED: for CPU %d, status is %d\n", 171 cpu, status); 172 goto cmd_incomplete; 173 } 174 iowrite16(0, &pcch_hdr->status); 175 curr_freq = (((ioread32(&pcch_hdr->nominal) * (output_buffer & 0xff)) 176 / 100) * 1000); 177 178 pr_debug("get: SUCCESS: (virtual) output_offset for cpu %d is " 179 "0x%p, contains a value of: 0x%x. Speed is: %d MHz\n", 180 cpu, (pcch_virt_addr + pcc_cpu_data->output_offset), 181 output_buffer, curr_freq); 182 183 freq_limit = (output_buffer >> 8) & 0xff; 184 if (freq_limit != 0xff) { 185 pr_debug("get: frequency for cpu %d is being temporarily" 186 " capped at %d\n", cpu, curr_freq); 187 } 188 189 spin_unlock(&pcc_lock); 190 return curr_freq; 191 192cmd_incomplete: 193 iowrite16(0, &pcch_hdr->status); 194 spin_unlock(&pcc_lock); 195 return 0; 196} 197 198static int pcc_cpufreq_target(struct cpufreq_policy *policy, 199 unsigned int target_freq, 200 unsigned int relation) 201{ 202 struct pcc_cpu *pcc_cpu_data; 203 struct cpufreq_freqs freqs; 204 u16 status; 205 u32 input_buffer; 206 int cpu; 207 208 spin_lock(&pcc_lock); 209 cpu = policy->cpu; 210 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 211 212 pr_debug("target: CPU %d should go to target freq: %d " 213 "(virtual) input_offset is 0x%p\n", 214 cpu, target_freq, 215 (pcch_virt_addr + pcc_cpu_data->input_offset)); 216 217 freqs.new = target_freq; 218 freqs.cpu = cpu; 219 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 220 221 input_buffer = 0x1 | (((target_freq * 100) 222 / (ioread32(&pcch_hdr->nominal) * 1000)) << 8); 223 iowrite32(input_buffer, 224 (pcch_virt_addr + pcc_cpu_data->input_offset)); 225 iowrite16(CMD_SET_FREQ, &pcch_hdr->command); 226 227 pcc_cmd(); 228 229 /* Clear the input buffer - we are done with the current command */ 230 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ); 231 232 status = ioread16(&pcch_hdr->status); 233 if (status != CMD_COMPLETE) { 234 pr_debug("target: FAILED for cpu %d, with status: 0x%x\n", 235 cpu, status); 236 goto cmd_incomplete; 237 } 238 iowrite16(0, &pcch_hdr->status); 239 240 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 241 pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu); 242 spin_unlock(&pcc_lock); 243 244 return 0; 245 246cmd_incomplete: 247 iowrite16(0, &pcch_hdr->status); 248 spin_unlock(&pcc_lock); 249 return -EINVAL; 250} 251 252static int pcc_get_offset(int cpu) 253{ 254 acpi_status status; 255 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; 256 union acpi_object *pccp, *offset; 257 struct pcc_cpu *pcc_cpu_data; 258 struct acpi_processor *pr; 259 int ret = 0; 260 261 pr = per_cpu(processors, cpu); 262 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 263 264 if (!pr) 265 return -ENODEV; 266 267 status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer); 268 if (ACPI_FAILURE(status)) 269 return -ENODEV; 270 271 pccp = buffer.pointer; 272 if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) { 273 ret = -ENODEV; 274 goto out_free; 275 }; 276 277 offset = &(pccp->package.elements[0]); 278 if (!offset || offset->type != ACPI_TYPE_INTEGER) { 279 ret = -ENODEV; 280 goto out_free; 281 } 282 283 pcc_cpu_data->input_offset = offset->integer.value; 284 285 offset = &(pccp->package.elements[1]); 286 if (!offset || offset->type != ACPI_TYPE_INTEGER) { 287 ret = -ENODEV; 288 goto out_free; 289 } 290 291 pcc_cpu_data->output_offset = offset->integer.value; 292 293 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ); 294 memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ); 295 296 pr_debug("pcc_get_offset: for CPU %d: pcc_cpu_data " 297 "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n", 298 cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset); 299out_free: 300 kfree(buffer.pointer); 301 return ret; 302} 303 304static int __init pcc_cpufreq_do_osc(acpi_handle *handle) 305{ 306 acpi_status status; 307 struct acpi_object_list input; 308 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; 309 union acpi_object in_params[4]; 310 union acpi_object *out_obj; 311 u32 capabilities[2]; 312 u32 errors; 313 u32 supported; 314 int ret = 0; 315 316 input.count = 4; 317 input.pointer = in_params; 318 in_params[0].type = ACPI_TYPE_BUFFER; 319 in_params[0].buffer.length = 16; 320 in_params[0].buffer.pointer = OSC_UUID; 321 in_params[1].type = ACPI_TYPE_INTEGER; 322 in_params[1].integer.value = 1; 323 in_params[2].type = ACPI_TYPE_INTEGER; 324 in_params[2].integer.value = 2; 325 in_params[3].type = ACPI_TYPE_BUFFER; 326 in_params[3].buffer.length = 8; 327 in_params[3].buffer.pointer = (u8 *)&capabilities; 328 329 capabilities[0] = OSC_QUERY_ENABLE; 330 capabilities[1] = 0x1; 331 332 status = acpi_evaluate_object(*handle, "_OSC", &input, &output); 333 if (ACPI_FAILURE(status)) 334 return -ENODEV; 335 336 if (!output.length) 337 return -ENODEV; 338 339 out_obj = output.pointer; 340 if (out_obj->type != ACPI_TYPE_BUFFER) { 341 ret = -ENODEV; 342 goto out_free; 343 } 344 345 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0); 346 if (errors) { 347 ret = -ENODEV; 348 goto out_free; 349 } 350 351 supported = *((u32 *)(out_obj->buffer.pointer + 4)); 352 if (!(supported & 0x1)) { 353 ret = -ENODEV; 354 goto out_free; 355 } 356 357 kfree(output.pointer); 358 capabilities[0] = 0x0; 359 capabilities[1] = 0x1; 360 361 status = acpi_evaluate_object(*handle, "_OSC", &input, &output); 362 if (ACPI_FAILURE(status)) 363 return -ENODEV; 364 365 if (!output.length) 366 return -ENODEV; 367 368 out_obj = output.pointer; 369 if (out_obj->type != ACPI_TYPE_BUFFER) { 370 ret = -ENODEV; 371 goto out_free; 372 } 373 374 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0); 375 if (errors) { 376 ret = -ENODEV; 377 goto out_free; 378 } 379 380 supported = *((u32 *)(out_obj->buffer.pointer + 4)); 381 if (!(supported & 0x1)) { 382 ret = -ENODEV; 383 goto out_free; 384 } 385 386out_free: 387 kfree(output.pointer); 388 return ret; 389} 390 391static int __init pcc_cpufreq_probe(void) 392{ 393 acpi_status status; 394 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; 395 struct pcc_memory_resource *mem_resource; 396 struct pcc_register_resource *reg_resource; 397 union acpi_object *out_obj, *member; 398 acpi_handle handle, osc_handle, pcch_handle; 399 int ret = 0; 400 401 status = acpi_get_handle(NULL, "\\_SB", &handle); 402 if (ACPI_FAILURE(status)) 403 return -ENODEV; 404 405 status = acpi_get_handle(handle, "PCCH", &pcch_handle); 406 if (ACPI_FAILURE(status)) 407 return -ENODEV; 408 409 status = acpi_get_handle(handle, "_OSC", &osc_handle); 410 if (ACPI_SUCCESS(status)) { 411 ret = pcc_cpufreq_do_osc(&osc_handle); 412 if (ret) 413 pr_debug("probe: _OSC evaluation did not succeed\n"); 414 /* Firmware's use of _OSC is optional */ 415 ret = 0; 416 } 417 418 status = acpi_evaluate_object(handle, "PCCH", NULL, &output); 419 if (ACPI_FAILURE(status)) 420 return -ENODEV; 421 422 out_obj = output.pointer; 423 if (out_obj->type != ACPI_TYPE_PACKAGE) { 424 ret = -ENODEV; 425 goto out_free; 426 } 427 428 member = &out_obj->package.elements[0]; 429 if (member->type != ACPI_TYPE_BUFFER) { 430 ret = -ENODEV; 431 goto out_free; 432 } 433 434 mem_resource = (struct pcc_memory_resource *)member->buffer.pointer; 435 436 pr_debug("probe: mem_resource descriptor: 0x%x," 437 " length: %d, space_id: %d, resource_usage: %d," 438 " type_specific: %d, granularity: 0x%llx," 439 " minimum: 0x%llx, maximum: 0x%llx," 440 " translation_offset: 0x%llx, address_length: 0x%llx\n", 441 mem_resource->descriptor, mem_resource->length, 442 mem_resource->space_id, mem_resource->resource_usage, 443 mem_resource->type_specific, mem_resource->granularity, 444 mem_resource->minimum, mem_resource->maximum, 445 mem_resource->translation_offset, 446 mem_resource->address_length); 447 448 if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) { 449 ret = -ENODEV; 450 goto out_free; 451 } 452 453 pcch_virt_addr = ioremap_nocache(mem_resource->minimum, 454 mem_resource->address_length); 455 if (pcch_virt_addr == NULL) { 456 pr_debug("probe: could not map shared mem region\n"); 457 goto out_free; 458 } 459 pcch_hdr = pcch_virt_addr; 460 461 pr_debug("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr); 462 pr_debug("probe: PCCH header is at physical address: 0x%llx," 463 " signature: 0x%x, length: %d bytes, major: %d, minor: %d," 464 " supported features: 0x%x, command field: 0x%x," 465 " status field: 0x%x, nominal latency: %d us\n", 466 mem_resource->minimum, ioread32(&pcch_hdr->signature), 467 ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major), 468 ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features), 469 ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status), 470 ioread32(&pcch_hdr->latency)); 471 472 pr_debug("probe: min time between commands: %d us," 473 " max time between commands: %d us," 474 " nominal CPU frequency: %d MHz," 475 " minimum CPU frequency: %d MHz," 476 " minimum CPU frequency without throttling: %d MHz\n", 477 ioread32(&pcch_hdr->minimum_time), 478 ioread32(&pcch_hdr->maximum_time), 479 ioread32(&pcch_hdr->nominal), 480 ioread32(&pcch_hdr->throttled_frequency), 481 ioread32(&pcch_hdr->minimum_frequency)); 482 483 member = &out_obj->package.elements[1]; 484 if (member->type != ACPI_TYPE_BUFFER) { 485 ret = -ENODEV; 486 goto pcch_free; 487 } 488 489 reg_resource = (struct pcc_register_resource *)member->buffer.pointer; 490 491 doorbell.space_id = reg_resource->space_id; 492 doorbell.bit_width = reg_resource->bit_width; 493 doorbell.bit_offset = reg_resource->bit_offset; 494 doorbell.access_width = 64; 495 doorbell.address = reg_resource->address; 496 497 pr_debug("probe: doorbell: space_id is %d, bit_width is %d, " 498 "bit_offset is %d, access_width is %d, address is 0x%llx\n", 499 doorbell.space_id, doorbell.bit_width, doorbell.bit_offset, 500 doorbell.access_width, reg_resource->address); 501 502 member = &out_obj->package.elements[2]; 503 if (member->type != ACPI_TYPE_INTEGER) { 504 ret = -ENODEV; 505 goto pcch_free; 506 } 507 508 doorbell_preserve = member->integer.value; 509 510 member = &out_obj->package.elements[3]; 511 if (member->type != ACPI_TYPE_INTEGER) { 512 ret = -ENODEV; 513 goto pcch_free; 514 } 515 516 doorbell_write = member->integer.value; 517 518 pr_debug("probe: doorbell_preserve: 0x%llx," 519 " doorbell_write: 0x%llx\n", 520 doorbell_preserve, doorbell_write); 521 522 pcc_cpu_info = alloc_percpu(struct pcc_cpu); 523 if (!pcc_cpu_info) { 524 ret = -ENOMEM; 525 goto pcch_free; 526 } 527 528 printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency" 529 " limits: %d MHz, %d MHz\n", PCC_VERSION, 530 ioread32(&pcch_hdr->minimum_frequency), 531 ioread32(&pcch_hdr->nominal)); 532 kfree(output.pointer); 533 return ret; 534pcch_free: 535 pcc_clear_mapping(); 536out_free: 537 kfree(output.pointer); 538 return ret; 539} 540 541static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy) 542{ 543 unsigned int cpu = policy->cpu; 544 unsigned int result = 0; 545 546 if (!pcch_virt_addr) { 547 result = -1; 548 goto out; 549 } 550 551 result = pcc_get_offset(cpu); 552 if (result) { 553 pr_debug("init: PCCP evaluation failed\n"); 554 goto out; 555 } 556 557 policy->max = policy->cpuinfo.max_freq = 558 ioread32(&pcch_hdr->nominal) * 1000; 559 policy->min = policy->cpuinfo.min_freq = 560 ioread32(&pcch_hdr->minimum_frequency) * 1000; 561 policy->cur = pcc_get_freq(cpu); 562 563 if (!policy->cur) { 564 pr_debug("init: Unable to get current CPU frequency\n"); 565 result = -EINVAL; 566 goto out; 567 } 568 569 pr_debug("init: policy->max is %d, policy->min is %d\n", 570 policy->max, policy->min); 571out: 572 return result; 573} 574 575static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy) 576{ 577 return 0; 578} 579 580static struct cpufreq_driver pcc_cpufreq_driver = { 581 .flags = CPUFREQ_CONST_LOOPS, 582 .get = pcc_get_freq, 583 .verify = pcc_cpufreq_verify, 584 .target = pcc_cpufreq_target, 585 .init = pcc_cpufreq_cpu_init, 586 .exit = pcc_cpufreq_cpu_exit, 587 .name = "pcc-cpufreq", 588 .owner = THIS_MODULE, 589}; 590 591static int __init pcc_cpufreq_init(void) 592{ 593 int ret; 594 595 if (acpi_disabled) 596 return 0; 597 598 ret = pcc_cpufreq_probe(); 599 if (ret) { 600 pr_debug("pcc_cpufreq_init: PCCH evaluation failed\n"); 601 return ret; 602 } 603 604 ret = cpufreq_register_driver(&pcc_cpufreq_driver); 605 606 return ret; 607} 608 609static void __exit pcc_cpufreq_exit(void) 610{ 611 cpufreq_unregister_driver(&pcc_cpufreq_driver); 612 613 pcc_clear_mapping(); 614 615 free_percpu(pcc_cpu_info); 616} 617 618MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar"); 619MODULE_VERSION(PCC_VERSION); 620MODULE_DESCRIPTION("Processor Clocking Control interface driver"); 621MODULE_LICENSE("GPL"); 622 623late_initcall(pcc_cpufreq_init); 624module_exit(pcc_cpufreq_exit); 625