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 #include <linux/platform_device.h> 35 36 #include <linux/acpi.h> 37 #include <linux/io.h> 38 #include <linux/spinlock.h> 39 #include <linux/uaccess.h> 40 41 #include <acpi/processor.h> 42 43 #define PCC_VERSION "1.10.00" 44 #define POLL_LOOPS 300 45 46 #define CMD_COMPLETE 0x1 47 #define CMD_GET_FREQ 0x0 48 #define CMD_SET_FREQ 0x1 49 50 #define BUF_SZ 4 51 52 struct pcc_register_resource { 53 u8 descriptor; 54 u16 length; 55 u8 space_id; 56 u8 bit_width; 57 u8 bit_offset; 58 u8 access_size; 59 u64 address; 60 } __attribute__ ((packed)); 61 62 struct pcc_memory_resource { 63 u8 descriptor; 64 u16 length; 65 u8 space_id; 66 u8 resource_usage; 67 u8 type_specific; 68 u64 granularity; 69 u64 minimum; 70 u64 maximum; 71 u64 translation_offset; 72 u64 address_length; 73 } __attribute__ ((packed)); 74 75 static struct cpufreq_driver pcc_cpufreq_driver; 76 77 struct pcc_header { 78 u32 signature; 79 u16 length; 80 u8 major; 81 u8 minor; 82 u32 features; 83 u16 command; 84 u16 status; 85 u32 latency; 86 u32 minimum_time; 87 u32 maximum_time; 88 u32 nominal; 89 u32 throttled_frequency; 90 u32 minimum_frequency; 91 }; 92 93 static void __iomem *pcch_virt_addr; 94 static struct pcc_header __iomem *pcch_hdr; 95 96 static DEFINE_SPINLOCK(pcc_lock); 97 98 static struct acpi_generic_address doorbell; 99 100 static u64 doorbell_preserve; 101 static u64 doorbell_write; 102 103 static u8 OSC_UUID[16] = {0x9F, 0x2C, 0x9B, 0x63, 0x91, 0x70, 0x1f, 0x49, 104 0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46}; 105 106 struct pcc_cpu { 107 u32 input_offset; 108 u32 output_offset; 109 }; 110 111 static struct pcc_cpu __percpu *pcc_cpu_info; 112 113 static int pcc_cpufreq_verify(struct cpufreq_policy_data *policy) 114 { 115 cpufreq_verify_within_cpu_limits(policy); 116 return 0; 117 } 118 119 static 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 } 133 134 static inline void pcc_clear_mapping(void) 135 { 136 if (pcch_virt_addr) 137 iounmap(pcch_virt_addr); 138 pcch_virt_addr = NULL; 139 } 140 141 static 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; 191 192 cmd_incomplete: 193 iowrite16(0, &pcch_hdr->status); 194 spin_unlock(&pcc_lock); 195 return 0; 196 } 197 198 static 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 cpu = policy->cpu; 209 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 210 211 pr_debug("target: CPU %d should go to target freq: %d " 212 "(virtual) input_offset is 0x%p\n", 213 cpu, target_freq, 214 (pcch_virt_addr + pcc_cpu_data->input_offset)); 215 216 freqs.old = policy->cur; 217 freqs.new = target_freq; 218 cpufreq_freq_transition_begin(policy, &freqs); 219 spin_lock(&pcc_lock); 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 iowrite16(0, &pcch_hdr->status); 234 235 spin_unlock(&pcc_lock); 236 cpufreq_freq_transition_end(policy, &freqs, status != CMD_COMPLETE); 237 238 if (status != CMD_COMPLETE) { 239 pr_debug("target: FAILED for cpu %d, with status: 0x%x\n", 240 cpu, status); 241 return -EINVAL; 242 } 243 244 pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu); 245 246 return 0; 247 } 248 249 static int pcc_get_offset(int cpu) 250 { 251 acpi_status status; 252 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; 253 union acpi_object *pccp, *offset; 254 struct pcc_cpu *pcc_cpu_data; 255 struct acpi_processor *pr; 256 int ret = 0; 257 258 pr = per_cpu(processors, cpu); 259 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 260 261 if (!pr) 262 return -ENODEV; 263 264 status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer); 265 if (ACPI_FAILURE(status)) 266 return -ENODEV; 267 268 pccp = buffer.pointer; 269 if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) { 270 ret = -ENODEV; 271 goto out_free; 272 } 273 274 offset = &(pccp->package.elements[0]); 275 if (!offset || offset->type != ACPI_TYPE_INTEGER) { 276 ret = -ENODEV; 277 goto out_free; 278 } 279 280 pcc_cpu_data->input_offset = offset->integer.value; 281 282 offset = &(pccp->package.elements[1]); 283 if (!offset || offset->type != ACPI_TYPE_INTEGER) { 284 ret = -ENODEV; 285 goto out_free; 286 } 287 288 pcc_cpu_data->output_offset = offset->integer.value; 289 290 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ); 291 memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ); 292 293 pr_debug("pcc_get_offset: for CPU %d: pcc_cpu_data " 294 "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n", 295 cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset); 296 out_free: 297 kfree(buffer.pointer); 298 return ret; 299 } 300 301 static int __init pcc_cpufreq_do_osc(acpi_handle *handle) 302 { 303 acpi_status status; 304 struct acpi_object_list input; 305 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; 306 union acpi_object in_params[4]; 307 union acpi_object *out_obj; 308 u32 capabilities[2]; 309 u32 errors; 310 u32 supported; 311 int ret = 0; 312 313 input.count = 4; 314 input.pointer = in_params; 315 in_params[0].type = ACPI_TYPE_BUFFER; 316 in_params[0].buffer.length = 16; 317 in_params[0].buffer.pointer = OSC_UUID; 318 in_params[1].type = ACPI_TYPE_INTEGER; 319 in_params[1].integer.value = 1; 320 in_params[2].type = ACPI_TYPE_INTEGER; 321 in_params[2].integer.value = 2; 322 in_params[3].type = ACPI_TYPE_BUFFER; 323 in_params[3].buffer.length = 8; 324 in_params[3].buffer.pointer = (u8 *)&capabilities; 325 326 capabilities[0] = OSC_QUERY_ENABLE; 327 capabilities[1] = 0x1; 328 329 status = acpi_evaluate_object(*handle, "_OSC", &input, &output); 330 if (ACPI_FAILURE(status)) 331 return -ENODEV; 332 333 if (!output.length) 334 return -ENODEV; 335 336 out_obj = output.pointer; 337 if (out_obj->type != ACPI_TYPE_BUFFER) { 338 ret = -ENODEV; 339 goto out_free; 340 } 341 342 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0); 343 if (errors) { 344 ret = -ENODEV; 345 goto out_free; 346 } 347 348 supported = *((u32 *)(out_obj->buffer.pointer + 4)); 349 if (!(supported & 0x1)) { 350 ret = -ENODEV; 351 goto out_free; 352 } 353 354 kfree(output.pointer); 355 capabilities[0] = 0x0; 356 capabilities[1] = 0x1; 357 358 status = acpi_evaluate_object(*handle, "_OSC", &input, &output); 359 if (ACPI_FAILURE(status)) 360 return -ENODEV; 361 362 if (!output.length) 363 return -ENODEV; 364 365 out_obj = output.pointer; 366 if (out_obj->type != ACPI_TYPE_BUFFER) { 367 ret = -ENODEV; 368 goto out_free; 369 } 370 371 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0); 372 if (errors) { 373 ret = -ENODEV; 374 goto out_free; 375 } 376 377 supported = *((u32 *)(out_obj->buffer.pointer + 4)); 378 if (!(supported & 0x1)) { 379 ret = -ENODEV; 380 goto out_free; 381 } 382 383 out_free: 384 kfree(output.pointer); 385 return ret; 386 } 387 388 static int __init pcc_cpufreq_evaluate(void) 389 { 390 acpi_status status; 391 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; 392 struct pcc_memory_resource *mem_resource; 393 struct pcc_register_resource *reg_resource; 394 union acpi_object *out_obj, *member; 395 acpi_handle handle, osc_handle; 396 int ret = 0; 397 398 status = acpi_get_handle(NULL, "\\_SB", &handle); 399 if (ACPI_FAILURE(status)) 400 return -ENODEV; 401 402 if (!acpi_has_method(handle, "PCCH")) 403 return -ENODEV; 404 405 status = acpi_get_handle(handle, "_OSC", &osc_handle); 406 if (ACPI_SUCCESS(status)) { 407 ret = pcc_cpufreq_do_osc(&osc_handle); 408 if (ret) 409 pr_debug("probe: _OSC evaluation did not succeed\n"); 410 /* Firmware's use of _OSC is optional */ 411 ret = 0; 412 } 413 414 status = acpi_evaluate_object(handle, "PCCH", NULL, &output); 415 if (ACPI_FAILURE(status)) 416 return -ENODEV; 417 418 out_obj = output.pointer; 419 if (out_obj->type != ACPI_TYPE_PACKAGE) { 420 ret = -ENODEV; 421 goto out_free; 422 } 423 424 member = &out_obj->package.elements[0]; 425 if (member->type != ACPI_TYPE_BUFFER) { 426 ret = -ENODEV; 427 goto out_free; 428 } 429 430 mem_resource = (struct pcc_memory_resource *)member->buffer.pointer; 431 432 pr_debug("probe: mem_resource descriptor: 0x%x," 433 " length: %d, space_id: %d, resource_usage: %d," 434 " type_specific: %d, granularity: 0x%llx," 435 " minimum: 0x%llx, maximum: 0x%llx," 436 " translation_offset: 0x%llx, address_length: 0x%llx\n", 437 mem_resource->descriptor, mem_resource->length, 438 mem_resource->space_id, mem_resource->resource_usage, 439 mem_resource->type_specific, mem_resource->granularity, 440 mem_resource->minimum, mem_resource->maximum, 441 mem_resource->translation_offset, 442 mem_resource->address_length); 443 444 if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) { 445 ret = -ENODEV; 446 goto out_free; 447 } 448 449 pcch_virt_addr = ioremap(mem_resource->minimum, 450 mem_resource->address_length); 451 if (pcch_virt_addr == NULL) { 452 pr_debug("probe: could not map shared mem region\n"); 453 ret = -ENOMEM; 454 goto out_free; 455 } 456 pcch_hdr = pcch_virt_addr; 457 458 pr_debug("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr); 459 pr_debug("probe: PCCH header is at physical address: 0x%llx," 460 " signature: 0x%x, length: %d bytes, major: %d, minor: %d," 461 " supported features: 0x%x, command field: 0x%x," 462 " status field: 0x%x, nominal latency: %d us\n", 463 mem_resource->minimum, ioread32(&pcch_hdr->signature), 464 ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major), 465 ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features), 466 ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status), 467 ioread32(&pcch_hdr->latency)); 468 469 pr_debug("probe: min time between commands: %d us," 470 " max time between commands: %d us," 471 " nominal CPU frequency: %d MHz," 472 " minimum CPU frequency: %d MHz," 473 " minimum CPU frequency without throttling: %d MHz\n", 474 ioread32(&pcch_hdr->minimum_time), 475 ioread32(&pcch_hdr->maximum_time), 476 ioread32(&pcch_hdr->nominal), 477 ioread32(&pcch_hdr->throttled_frequency), 478 ioread32(&pcch_hdr->minimum_frequency)); 479 480 member = &out_obj->package.elements[1]; 481 if (member->type != ACPI_TYPE_BUFFER) { 482 ret = -ENODEV; 483 goto pcch_free; 484 } 485 486 reg_resource = (struct pcc_register_resource *)member->buffer.pointer; 487 488 doorbell.space_id = reg_resource->space_id; 489 doorbell.bit_width = reg_resource->bit_width; 490 doorbell.bit_offset = reg_resource->bit_offset; 491 doorbell.access_width = 4; 492 doorbell.address = reg_resource->address; 493 494 pr_debug("probe: doorbell: space_id is %d, bit_width is %d, " 495 "bit_offset is %d, access_width is %d, address is 0x%llx\n", 496 doorbell.space_id, doorbell.bit_width, doorbell.bit_offset, 497 doorbell.access_width, reg_resource->address); 498 499 member = &out_obj->package.elements[2]; 500 if (member->type != ACPI_TYPE_INTEGER) { 501 ret = -ENODEV; 502 goto pcch_free; 503 } 504 505 doorbell_preserve = member->integer.value; 506 507 member = &out_obj->package.elements[3]; 508 if (member->type != ACPI_TYPE_INTEGER) { 509 ret = -ENODEV; 510 goto pcch_free; 511 } 512 513 doorbell_write = member->integer.value; 514 515 pr_debug("probe: doorbell_preserve: 0x%llx," 516 " doorbell_write: 0x%llx\n", 517 doorbell_preserve, doorbell_write); 518 519 pcc_cpu_info = alloc_percpu(struct pcc_cpu); 520 if (!pcc_cpu_info) { 521 ret = -ENOMEM; 522 goto pcch_free; 523 } 524 525 printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency" 526 " limits: %d MHz, %d MHz\n", PCC_VERSION, 527 ioread32(&pcch_hdr->minimum_frequency), 528 ioread32(&pcch_hdr->nominal)); 529 kfree(output.pointer); 530 return ret; 531 pcch_free: 532 pcc_clear_mapping(); 533 out_free: 534 kfree(output.pointer); 535 return ret; 536 } 537 538 static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy) 539 { 540 unsigned int cpu = policy->cpu; 541 unsigned int result = 0; 542 543 if (!pcch_virt_addr) { 544 result = -1; 545 goto out; 546 } 547 548 result = pcc_get_offset(cpu); 549 if (result) { 550 pr_debug("init: PCCP evaluation failed\n"); 551 goto out; 552 } 553 554 policy->max = policy->cpuinfo.max_freq = 555 ioread32(&pcch_hdr->nominal) * 1000; 556 policy->min = policy->cpuinfo.min_freq = 557 ioread32(&pcch_hdr->minimum_frequency) * 1000; 558 559 pr_debug("init: policy->max is %d, policy->min is %d\n", 560 policy->max, policy->min); 561 out: 562 return result; 563 } 564 565 static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy) 566 { 567 return 0; 568 } 569 570 static struct cpufreq_driver pcc_cpufreq_driver = { 571 .flags = CPUFREQ_CONST_LOOPS, 572 .get = pcc_get_freq, 573 .verify = pcc_cpufreq_verify, 574 .target = pcc_cpufreq_target, 575 .init = pcc_cpufreq_cpu_init, 576 .exit = pcc_cpufreq_cpu_exit, 577 .name = "pcc-cpufreq", 578 }; 579 580 static int __init pcc_cpufreq_probe(struct platform_device *pdev) 581 { 582 int ret; 583 584 /* Skip initialization if another cpufreq driver is there. */ 585 if (cpufreq_get_current_driver()) 586 return -ENODEV; 587 588 if (acpi_disabled) 589 return -ENODEV; 590 591 ret = pcc_cpufreq_evaluate(); 592 if (ret) { 593 pr_debug("pcc_cpufreq_probe: PCCH evaluation failed\n"); 594 return ret; 595 } 596 597 if (num_present_cpus() > 4) { 598 pcc_cpufreq_driver.flags |= CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING; 599 pr_err("%s: Too many CPUs, dynamic performance scaling disabled\n", 600 __func__); 601 pr_err("%s: Try to enable another scaling driver through BIOS settings\n", 602 __func__); 603 pr_err("%s: and complain to the system vendor\n", __func__); 604 } 605 606 ret = cpufreq_register_driver(&pcc_cpufreq_driver); 607 608 return ret; 609 } 610 611 static void pcc_cpufreq_remove(struct platform_device *pdev) 612 { 613 cpufreq_unregister_driver(&pcc_cpufreq_driver); 614 615 pcc_clear_mapping(); 616 617 free_percpu(pcc_cpu_info); 618 } 619 620 static struct platform_driver pcc_cpufreq_platdrv = { 621 .driver = { 622 .name = "pcc-cpufreq", 623 }, 624 .remove_new = pcc_cpufreq_remove, 625 }; 626 627 static int __init pcc_cpufreq_init(void) 628 { 629 return platform_driver_probe(&pcc_cpufreq_platdrv, pcc_cpufreq_probe); 630 } 631 632 static void __exit pcc_cpufreq_exit(void) 633 { 634 platform_driver_unregister(&pcc_cpufreq_platdrv); 635 } 636 637 MODULE_ALIAS("platform:pcc-cpufreq"); 638 639 MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar"); 640 MODULE_VERSION(PCC_VERSION); 641 MODULE_DESCRIPTION("Processor Clocking Control interface driver"); 642 MODULE_LICENSE("GPL"); 643 644 late_initcall(pcc_cpufreq_init); 645 module_exit(pcc_cpufreq_exit); 646