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 "1.00.00" 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 51#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \ 52 "pcc-cpufreq", msg) 53 54struct pcc_register_resource { 55 u8 descriptor; 56 u16 length; 57 u8 space_id; 58 u8 bit_width; 59 u8 bit_offset; 60 u8 access_size; 61 u64 address; 62} __attribute__ ((packed)); 63 64struct pcc_memory_resource { 65 u8 descriptor; 66 u16 length; 67 u8 space_id; 68 u8 resource_usage; 69 u8 type_specific; 70 u64 granularity; 71 u64 minimum; 72 u64 maximum; 73 u64 translation_offset; 74 u64 address_length; 75} __attribute__ ((packed)); 76 77static struct cpufreq_driver pcc_cpufreq_driver; 78 79struct pcc_header { 80 u32 signature; 81 u16 length; 82 u8 major; 83 u8 minor; 84 u32 features; 85 u16 command; 86 u16 status; 87 u32 latency; 88 u32 minimum_time; 89 u32 maximum_time; 90 u32 nominal; 91 u32 throttled_frequency; 92 u32 minimum_frequency; 93}; 94 95static void __iomem *pcch_virt_addr; 96static struct pcc_header __iomem *pcch_hdr; 97 98static DEFINE_SPINLOCK(pcc_lock); 99 100static struct acpi_generic_address doorbell; 101 102static u64 doorbell_preserve; 103static u64 doorbell_write; 104 105static u8 OSC_UUID[16] = {0x63, 0x9B, 0x2C, 0x9F, 0x70, 0x91, 0x49, 0x1f, 106 0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46}; 107 108struct pcc_cpu { 109 u32 input_offset; 110 u32 output_offset; 111}; 112 113static struct pcc_cpu __percpu *pcc_cpu_info; 114 115static int pcc_cpufreq_verify(struct cpufreq_policy *policy) 116{ 117 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, 118 policy->cpuinfo.max_freq); 119 return 0; 120} 121 122static inline void pcc_cmd(void) 123{ 124 u64 doorbell_value; 125 int i; 126 127 acpi_read(&doorbell_value, &doorbell); 128 acpi_write((doorbell_value & doorbell_preserve) | doorbell_write, 129 &doorbell); 130 131 for (i = 0; i < POLL_LOOPS; i++) { 132 if (ioread16(&pcch_hdr->status) & CMD_COMPLETE) 133 break; 134 } 135} 136 137static inline void pcc_clear_mapping(void) 138{ 139 if (pcch_virt_addr) 140 iounmap(pcch_virt_addr); 141 pcch_virt_addr = NULL; 142} 143 144static unsigned int pcc_get_freq(unsigned int cpu) 145{ 146 struct pcc_cpu *pcc_cpu_data; 147 unsigned int curr_freq; 148 unsigned int freq_limit; 149 u16 status; 150 u32 input_buffer; 151 u32 output_buffer; 152 153 spin_lock(&pcc_lock); 154 155 dprintk("get: get_freq for CPU %d\n", cpu); 156 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 157 158 input_buffer = 0x1; 159 iowrite32(input_buffer, 160 (pcch_virt_addr + pcc_cpu_data->input_offset)); 161 iowrite16(CMD_GET_FREQ, &pcch_hdr->command); 162 163 pcc_cmd(); 164 165 output_buffer = 166 ioread32(pcch_virt_addr + pcc_cpu_data->output_offset); 167 168 /* Clear the input buffer - we are done with the current command */ 169 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ); 170 171 status = ioread16(&pcch_hdr->status); 172 if (status != CMD_COMPLETE) { 173 dprintk("get: FAILED: for CPU %d, status is %d\n", 174 cpu, status); 175 goto cmd_incomplete; 176 } 177 iowrite16(0, &pcch_hdr->status); 178 curr_freq = (((ioread32(&pcch_hdr->nominal) * (output_buffer & 0xff)) 179 / 100) * 1000); 180 181 dprintk("get: SUCCESS: (virtual) output_offset for cpu %d is " 182 "0x%x, contains a value of: 0x%x. Speed is: %d MHz\n", 183 cpu, (pcch_virt_addr + pcc_cpu_data->output_offset), 184 output_buffer, curr_freq); 185 186 freq_limit = (output_buffer >> 8) & 0xff; 187 if (freq_limit != 0xff) { 188 dprintk("get: frequency for cpu %d is being temporarily" 189 " capped at %d\n", cpu, curr_freq); 190 } 191 192 spin_unlock(&pcc_lock); 193 return curr_freq; 194 195cmd_incomplete: 196 iowrite16(0, &pcch_hdr->status); 197 spin_unlock(&pcc_lock); 198 return -EINVAL; 199} 200 201static int pcc_cpufreq_target(struct cpufreq_policy *policy, 202 unsigned int target_freq, 203 unsigned int relation) 204{ 205 struct pcc_cpu *pcc_cpu_data; 206 struct cpufreq_freqs freqs; 207 u16 status; 208 u32 input_buffer; 209 int cpu; 210 211 spin_lock(&pcc_lock); 212 cpu = policy->cpu; 213 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 214 215 dprintk("target: CPU %d should go to target freq: %d " 216 "(virtual) input_offset is 0x%x\n", 217 cpu, target_freq, 218 (pcch_virt_addr + pcc_cpu_data->input_offset)); 219 220 freqs.new = target_freq; 221 freqs.cpu = cpu; 222 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 223 224 input_buffer = 0x1 | (((target_freq * 100) 225 / (ioread32(&pcch_hdr->nominal) * 1000)) << 8); 226 iowrite32(input_buffer, 227 (pcch_virt_addr + pcc_cpu_data->input_offset)); 228 iowrite16(CMD_SET_FREQ, &pcch_hdr->command); 229 230 pcc_cmd(); 231 232 /* Clear the input buffer - we are done with the current command */ 233 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ); 234 235 status = ioread16(&pcch_hdr->status); 236 if (status != CMD_COMPLETE) { 237 dprintk("target: FAILED for cpu %d, with status: 0x%x\n", 238 cpu, status); 239 goto cmd_incomplete; 240 } 241 iowrite16(0, &pcch_hdr->status); 242 243 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 244 dprintk("target: was SUCCESSFUL for cpu %d\n", cpu); 245 spin_unlock(&pcc_lock); 246 247 return 0; 248 249cmd_incomplete: 250 iowrite16(0, &pcch_hdr->status); 251 spin_unlock(&pcc_lock); 252 return -EINVAL; 253} 254 255static int pcc_get_offset(int cpu) 256{ 257 acpi_status status; 258 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; 259 union acpi_object *pccp, *offset; 260 struct pcc_cpu *pcc_cpu_data; 261 struct acpi_processor *pr; 262 int ret = 0; 263 264 pr = per_cpu(processors, cpu); 265 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 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 dprintk("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 input.count = 4; 319 input.pointer = in_params; 320 in_params[0].type = ACPI_TYPE_BUFFER; 321 in_params[0].buffer.length = 16; 322 in_params[0].buffer.pointer = OSC_UUID; 323 in_params[1].type = ACPI_TYPE_INTEGER; 324 in_params[1].integer.value = 1; 325 in_params[2].type = ACPI_TYPE_INTEGER; 326 in_params[2].integer.value = 2; 327 in_params[3].type = ACPI_TYPE_BUFFER; 328 in_params[3].buffer.length = 8; 329 in_params[3].buffer.pointer = (u8 *)&capabilities; 330 331 capabilities[0] = OSC_QUERY_ENABLE; 332 capabilities[1] = 0x1; 333 334 status = acpi_evaluate_object(*handle, "_OSC", &input, &output); 335 if (ACPI_FAILURE(status)) 336 return -ENODEV; 337 338 if (!output.length) 339 return -ENODEV; 340 341 out_obj = output.pointer; 342 if (out_obj->type != ACPI_TYPE_BUFFER) { 343 ret = -ENODEV; 344 goto out_free; 345 } 346 347 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0); 348 if (errors) { 349 ret = -ENODEV; 350 goto out_free; 351 } 352 353 supported = *((u32 *)(out_obj->buffer.pointer + 4)); 354 if (!(supported & 0x1)) { 355 ret = -ENODEV; 356 goto out_free; 357 } 358 359 kfree(output.pointer); 360 capabilities[0] = 0x0; 361 capabilities[1] = 0x1; 362 363 status = acpi_evaluate_object(*handle, "_OSC", &input, &output); 364 if (ACPI_FAILURE(status)) 365 return -ENODEV; 366 367 if (!output.length) 368 return -ENODEV; 369 370 out_obj = output.pointer; 371 if (out_obj->type != ACPI_TYPE_BUFFER) { 372 ret = -ENODEV; 373 goto out_free; 374 } 375 376 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0); 377 if (errors) { 378 ret = -ENODEV; 379 goto out_free; 380 } 381 382 supported = *((u32 *)(out_obj->buffer.pointer + 4)); 383 if (!(supported & 0x1)) { 384 ret = -ENODEV; 385 goto out_free; 386 } 387 388out_free: 389 kfree(output.pointer); 390 return ret; 391} 392 393static int __init pcc_cpufreq_probe(void) 394{ 395 acpi_status status; 396 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; 397 struct pcc_memory_resource *mem_resource; 398 struct pcc_register_resource *reg_resource; 399 union acpi_object *out_obj, *member; 400 acpi_handle handle, osc_handle, pcch_handle; 401 int ret = 0; 402 403 status = acpi_get_handle(NULL, "\\_SB", &handle); 404 if (ACPI_FAILURE(status)) 405 return -ENODEV; 406 407 status = acpi_get_handle(handle, "PCCH", &pcch_handle); 408 if (ACPI_FAILURE(status)) 409 return -ENODEV; 410 411 status = acpi_get_handle(handle, "_OSC", &osc_handle); 412 if (ACPI_SUCCESS(status)) { 413 ret = pcc_cpufreq_do_osc(&osc_handle); 414 if (ret) 415 dprintk("probe: _OSC evaluation did not succeed\n"); 416 /* Firmware's use of _OSC is optional */ 417 ret = 0; 418 } 419 420 status = acpi_evaluate_object(handle, "PCCH", NULL, &output); 421 if (ACPI_FAILURE(status)) 422 return -ENODEV; 423 424 out_obj = output.pointer; 425 if (out_obj->type != ACPI_TYPE_PACKAGE) { 426 ret = -ENODEV; 427 goto out_free; 428 } 429 430 member = &out_obj->package.elements[0]; 431 if (member->type != ACPI_TYPE_BUFFER) { 432 ret = -ENODEV; 433 goto out_free; 434 } 435 436 mem_resource = (struct pcc_memory_resource *)member->buffer.pointer; 437 438 dprintk("probe: mem_resource descriptor: 0x%x," 439 " length: %d, space_id: %d, resource_usage: %d," 440 " type_specific: %d, granularity: 0x%llx," 441 " minimum: 0x%llx, maximum: 0x%llx," 442 " translation_offset: 0x%llx, address_length: 0x%llx\n", 443 mem_resource->descriptor, mem_resource->length, 444 mem_resource->space_id, mem_resource->resource_usage, 445 mem_resource->type_specific, mem_resource->granularity, 446 mem_resource->minimum, mem_resource->maximum, 447 mem_resource->translation_offset, 448 mem_resource->address_length); 449 450 if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) { 451 ret = -ENODEV; 452 goto out_free; 453 } 454 455 pcch_virt_addr = ioremap_nocache(mem_resource->minimum, 456 mem_resource->address_length); 457 if (pcch_virt_addr == NULL) { 458 dprintk("probe: could not map shared mem region\n"); 459 goto out_free; 460 } 461 pcch_hdr = pcch_virt_addr; 462 463 dprintk("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr); 464 dprintk("probe: PCCH header is at physical address: 0x%llx," 465 " signature: 0x%x, length: %d bytes, major: %d, minor: %d," 466 " supported features: 0x%x, command field: 0x%x," 467 " status field: 0x%x, nominal latency: %d us\n", 468 mem_resource->minimum, ioread32(&pcch_hdr->signature), 469 ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major), 470 ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features), 471 ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status), 472 ioread32(&pcch_hdr->latency)); 473 474 dprintk("probe: min time between commands: %d us," 475 " max time between commands: %d us," 476 " nominal CPU frequency: %d MHz," 477 " minimum CPU frequency: %d MHz," 478 " minimum CPU frequency without throttling: %d MHz\n", 479 ioread32(&pcch_hdr->minimum_time), 480 ioread32(&pcch_hdr->maximum_time), 481 ioread32(&pcch_hdr->nominal), 482 ioread32(&pcch_hdr->throttled_frequency), 483 ioread32(&pcch_hdr->minimum_frequency)); 484 485 member = &out_obj->package.elements[1]; 486 if (member->type != ACPI_TYPE_BUFFER) { 487 ret = -ENODEV; 488 goto pcch_free; 489 } 490 491 reg_resource = (struct pcc_register_resource *)member->buffer.pointer; 492 493 doorbell.space_id = reg_resource->space_id; 494 doorbell.bit_width = reg_resource->bit_width; 495 doorbell.bit_offset = reg_resource->bit_offset; 496 doorbell.access_width = 64; 497 doorbell.address = reg_resource->address; 498 499 dprintk("probe: doorbell: space_id is %d, bit_width is %d, " 500 "bit_offset is %d, access_width is %d, address is 0x%llx\n", 501 doorbell.space_id, doorbell.bit_width, doorbell.bit_offset, 502 doorbell.access_width, reg_resource->address); 503 504 member = &out_obj->package.elements[2]; 505 if (member->type != ACPI_TYPE_INTEGER) { 506 ret = -ENODEV; 507 goto pcch_free; 508 } 509 510 doorbell_preserve = member->integer.value; 511 512 member = &out_obj->package.elements[3]; 513 if (member->type != ACPI_TYPE_INTEGER) { 514 ret = -ENODEV; 515 goto pcch_free; 516 } 517 518 doorbell_write = member->integer.value; 519 520 dprintk("probe: doorbell_preserve: 0x%llx," 521 " doorbell_write: 0x%llx\n", 522 doorbell_preserve, doorbell_write); 523 524 pcc_cpu_info = alloc_percpu(struct pcc_cpu); 525 if (!pcc_cpu_info) { 526 ret = -ENOMEM; 527 goto pcch_free; 528 } 529 530 printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency" 531 " limits: %d MHz, %d MHz\n", PCC_VERSION, 532 ioread32(&pcch_hdr->minimum_frequency), 533 ioread32(&pcch_hdr->nominal)); 534 kfree(output.pointer); 535 return ret; 536pcch_free: 537 pcc_clear_mapping(); 538out_free: 539 kfree(output.pointer); 540 return ret; 541} 542 543static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy) 544{ 545 unsigned int cpu = policy->cpu; 546 unsigned int result = 0; 547 548 if (!pcch_virt_addr) { 549 result = -1; 550 goto out; 551 } 552 553 result = pcc_get_offset(cpu); 554 if (result) { 555 dprintk("init: PCCP evaluation failed\n"); 556 goto out; 557 } 558 559 policy->max = policy->cpuinfo.max_freq = 560 ioread32(&pcch_hdr->nominal) * 1000; 561 policy->min = policy->cpuinfo.min_freq = 562 ioread32(&pcch_hdr->minimum_frequency) * 1000; 563 policy->cur = pcc_get_freq(cpu); 564 565 if (!policy->cur) { 566 dprintk("init: Unable to get current CPU frequency\n"); 567 result = -EINVAL; 568 goto out; 569 } 570 571 dprintk("init: policy->max is %d, policy->min is %d\n", 572 policy->max, policy->min); 573out: 574 return result; 575} 576 577static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy) 578{ 579 return 0; 580} 581 582static struct cpufreq_driver pcc_cpufreq_driver = { 583 .flags = CPUFREQ_CONST_LOOPS, 584 .get = pcc_get_freq, 585 .verify = pcc_cpufreq_verify, 586 .target = pcc_cpufreq_target, 587 .init = pcc_cpufreq_cpu_init, 588 .exit = pcc_cpufreq_cpu_exit, 589 .name = "pcc-cpufreq", 590 .owner = THIS_MODULE, 591}; 592 593static int __init pcc_cpufreq_init(void) 594{ 595 int ret; 596 597 if (acpi_disabled) 598 return 0; 599 600 ret = pcc_cpufreq_probe(); 601 if (ret) { 602 dprintk("pcc_cpufreq_init: PCCH evaluation failed\n"); 603 return ret; 604 } 605 606 ret = cpufreq_register_driver(&pcc_cpufreq_driver); 607 608 return ret; 609} 610 611static void __exit pcc_cpufreq_exit(void) 612{ 613 cpufreq_unregister_driver(&pcc_cpufreq_driver); 614 615 pcc_clear_mapping(); 616 617 free_percpu(pcc_cpu_info); 618} 619 620MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar"); 621MODULE_VERSION(PCC_VERSION); 622MODULE_DESCRIPTION("Processor Clocking Control interface driver"); 623MODULE_LICENSE("GPL"); 624 625late_initcall(pcc_cpufreq_init); 626module_exit(pcc_cpufreq_exit); 627