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 51 struct 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 61 struct 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 74 static struct cpufreq_driver pcc_cpufreq_driver; 75 76 struct 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 92 static void __iomem *pcch_virt_addr; 93 static struct pcc_header __iomem *pcch_hdr; 94 95 static DEFINE_SPINLOCK(pcc_lock); 96 97 static struct acpi_generic_address doorbell; 98 99 static u64 doorbell_preserve; 100 static u64 doorbell_write; 101 102 static u8 OSC_UUID[16] = {0x9F, 0x2C, 0x9B, 0x63, 0x91, 0x70, 0x1f, 0x49, 103 0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46}; 104 105 struct pcc_cpu { 106 u32 input_offset; 107 u32 output_offset; 108 }; 109 110 static struct pcc_cpu __percpu *pcc_cpu_info; 111 112 static int pcc_cpufreq_verify(struct cpufreq_policy *policy) 113 { 114 cpufreq_verify_within_cpu_limits(policy); 115 return 0; 116 } 117 118 static inline void pcc_cmd(void) 119 { 120 u64 doorbell_value; 121 int i; 122 123 acpi_read(&doorbell_value, &doorbell); 124 acpi_write((doorbell_value & doorbell_preserve) | doorbell_write, 125 &doorbell); 126 127 for (i = 0; i < POLL_LOOPS; i++) { 128 if (ioread16(&pcch_hdr->status) & CMD_COMPLETE) 129 break; 130 } 131 } 132 133 static inline void pcc_clear_mapping(void) 134 { 135 if (pcch_virt_addr) 136 iounmap(pcch_virt_addr); 137 pcch_virt_addr = NULL; 138 } 139 140 static unsigned int pcc_get_freq(unsigned int cpu) 141 { 142 struct pcc_cpu *pcc_cpu_data; 143 unsigned int curr_freq; 144 unsigned int freq_limit; 145 u16 status; 146 u32 input_buffer; 147 u32 output_buffer; 148 149 spin_lock(&pcc_lock); 150 151 pr_debug("get: get_freq for CPU %d\n", cpu); 152 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 153 154 input_buffer = 0x1; 155 iowrite32(input_buffer, 156 (pcch_virt_addr + pcc_cpu_data->input_offset)); 157 iowrite16(CMD_GET_FREQ, &pcch_hdr->command); 158 159 pcc_cmd(); 160 161 output_buffer = 162 ioread32(pcch_virt_addr + pcc_cpu_data->output_offset); 163 164 /* Clear the input buffer - we are done with the current command */ 165 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ); 166 167 status = ioread16(&pcch_hdr->status); 168 if (status != CMD_COMPLETE) { 169 pr_debug("get: FAILED: for CPU %d, status is %d\n", 170 cpu, status); 171 goto cmd_incomplete; 172 } 173 iowrite16(0, &pcch_hdr->status); 174 curr_freq = (((ioread32(&pcch_hdr->nominal) * (output_buffer & 0xff)) 175 / 100) * 1000); 176 177 pr_debug("get: SUCCESS: (virtual) output_offset for cpu %d is " 178 "0x%p, contains a value of: 0x%x. Speed is: %d MHz\n", 179 cpu, (pcch_virt_addr + pcc_cpu_data->output_offset), 180 output_buffer, curr_freq); 181 182 freq_limit = (output_buffer >> 8) & 0xff; 183 if (freq_limit != 0xff) { 184 pr_debug("get: frequency for cpu %d is being temporarily" 185 " capped at %d\n", cpu, curr_freq); 186 } 187 188 spin_unlock(&pcc_lock); 189 return curr_freq; 190 191 cmd_incomplete: 192 iowrite16(0, &pcch_hdr->status); 193 spin_unlock(&pcc_lock); 194 return 0; 195 } 196 197 static int pcc_cpufreq_target(struct cpufreq_policy *policy, 198 unsigned int target_freq, 199 unsigned int relation) 200 { 201 struct pcc_cpu *pcc_cpu_data; 202 struct cpufreq_freqs freqs; 203 u16 status; 204 u32 input_buffer; 205 int cpu; 206 207 cpu = policy->cpu; 208 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 209 210 pr_debug("target: CPU %d should go to target freq: %d " 211 "(virtual) input_offset is 0x%p\n", 212 cpu, target_freq, 213 (pcch_virt_addr + pcc_cpu_data->input_offset)); 214 215 freqs.old = policy->cur; 216 freqs.new = target_freq; 217 cpufreq_freq_transition_begin(policy, &freqs); 218 spin_lock(&pcc_lock); 219 220 input_buffer = 0x1 | (((target_freq * 100) 221 / (ioread32(&pcch_hdr->nominal) * 1000)) << 8); 222 iowrite32(input_buffer, 223 (pcch_virt_addr + pcc_cpu_data->input_offset)); 224 iowrite16(CMD_SET_FREQ, &pcch_hdr->command); 225 226 pcc_cmd(); 227 228 /* Clear the input buffer - we are done with the current command */ 229 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ); 230 231 status = ioread16(&pcch_hdr->status); 232 iowrite16(0, &pcch_hdr->status); 233 234 cpufreq_freq_transition_end(policy, &freqs, status != CMD_COMPLETE); 235 spin_unlock(&pcc_lock); 236 237 if (status != CMD_COMPLETE) { 238 pr_debug("target: FAILED for cpu %d, with status: 0x%x\n", 239 cpu, status); 240 return -EINVAL; 241 } 242 243 pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu); 244 245 return 0; 246 } 247 248 static int pcc_get_offset(int cpu) 249 { 250 acpi_status status; 251 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; 252 union acpi_object *pccp, *offset; 253 struct pcc_cpu *pcc_cpu_data; 254 struct acpi_processor *pr; 255 int ret = 0; 256 257 pr = per_cpu(processors, cpu); 258 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu); 259 260 if (!pr) 261 return -ENODEV; 262 263 status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer); 264 if (ACPI_FAILURE(status)) 265 return -ENODEV; 266 267 pccp = buffer.pointer; 268 if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) { 269 ret = -ENODEV; 270 goto out_free; 271 }; 272 273 offset = &(pccp->package.elements[0]); 274 if (!offset || offset->type != ACPI_TYPE_INTEGER) { 275 ret = -ENODEV; 276 goto out_free; 277 } 278 279 pcc_cpu_data->input_offset = offset->integer.value; 280 281 offset = &(pccp->package.elements[1]); 282 if (!offset || offset->type != ACPI_TYPE_INTEGER) { 283 ret = -ENODEV; 284 goto out_free; 285 } 286 287 pcc_cpu_data->output_offset = offset->integer.value; 288 289 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ); 290 memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ); 291 292 pr_debug("pcc_get_offset: for CPU %d: pcc_cpu_data " 293 "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n", 294 cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset); 295 out_free: 296 kfree(buffer.pointer); 297 return ret; 298 } 299 300 static int __init pcc_cpufreq_do_osc(acpi_handle *handle) 301 { 302 acpi_status status; 303 struct acpi_object_list input; 304 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; 305 union acpi_object in_params[4]; 306 union acpi_object *out_obj; 307 u32 capabilities[2]; 308 u32 errors; 309 u32 supported; 310 int ret = 0; 311 312 input.count = 4; 313 input.pointer = in_params; 314 in_params[0].type = ACPI_TYPE_BUFFER; 315 in_params[0].buffer.length = 16; 316 in_params[0].buffer.pointer = OSC_UUID; 317 in_params[1].type = ACPI_TYPE_INTEGER; 318 in_params[1].integer.value = 1; 319 in_params[2].type = ACPI_TYPE_INTEGER; 320 in_params[2].integer.value = 2; 321 in_params[3].type = ACPI_TYPE_BUFFER; 322 in_params[3].buffer.length = 8; 323 in_params[3].buffer.pointer = (u8 *)&capabilities; 324 325 capabilities[0] = OSC_QUERY_ENABLE; 326 capabilities[1] = 0x1; 327 328 status = acpi_evaluate_object(*handle, "_OSC", &input, &output); 329 if (ACPI_FAILURE(status)) 330 return -ENODEV; 331 332 if (!output.length) 333 return -ENODEV; 334 335 out_obj = output.pointer; 336 if (out_obj->type != ACPI_TYPE_BUFFER) { 337 ret = -ENODEV; 338 goto out_free; 339 } 340 341 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0); 342 if (errors) { 343 ret = -ENODEV; 344 goto out_free; 345 } 346 347 supported = *((u32 *)(out_obj->buffer.pointer + 4)); 348 if (!(supported & 0x1)) { 349 ret = -ENODEV; 350 goto out_free; 351 } 352 353 kfree(output.pointer); 354 capabilities[0] = 0x0; 355 capabilities[1] = 0x1; 356 357 status = acpi_evaluate_object(*handle, "_OSC", &input, &output); 358 if (ACPI_FAILURE(status)) 359 return -ENODEV; 360 361 if (!output.length) 362 return -ENODEV; 363 364 out_obj = output.pointer; 365 if (out_obj->type != ACPI_TYPE_BUFFER) { 366 ret = -ENODEV; 367 goto out_free; 368 } 369 370 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0); 371 if (errors) { 372 ret = -ENODEV; 373 goto out_free; 374 } 375 376 supported = *((u32 *)(out_obj->buffer.pointer + 4)); 377 if (!(supported & 0x1)) { 378 ret = -ENODEV; 379 goto out_free; 380 } 381 382 out_free: 383 kfree(output.pointer); 384 return ret; 385 } 386 387 static int __init pcc_cpufreq_probe(void) 388 { 389 acpi_status status; 390 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL}; 391 struct pcc_memory_resource *mem_resource; 392 struct pcc_register_resource *reg_resource; 393 union acpi_object *out_obj, *member; 394 acpi_handle handle, osc_handle; 395 int ret = 0; 396 397 status = acpi_get_handle(NULL, "\\_SB", &handle); 398 if (ACPI_FAILURE(status)) 399 return -ENODEV; 400 401 if (!acpi_has_method(handle, "PCCH")) 402 return -ENODEV; 403 404 status = acpi_get_handle(handle, "_OSC", &osc_handle); 405 if (ACPI_SUCCESS(status)) { 406 ret = pcc_cpufreq_do_osc(&osc_handle); 407 if (ret) 408 pr_debug("probe: _OSC evaluation did not succeed\n"); 409 /* Firmware's use of _OSC is optional */ 410 ret = 0; 411 } 412 413 status = acpi_evaluate_object(handle, "PCCH", NULL, &output); 414 if (ACPI_FAILURE(status)) 415 return -ENODEV; 416 417 out_obj = output.pointer; 418 if (out_obj->type != ACPI_TYPE_PACKAGE) { 419 ret = -ENODEV; 420 goto out_free; 421 } 422 423 member = &out_obj->package.elements[0]; 424 if (member->type != ACPI_TYPE_BUFFER) { 425 ret = -ENODEV; 426 goto out_free; 427 } 428 429 mem_resource = (struct pcc_memory_resource *)member->buffer.pointer; 430 431 pr_debug("probe: mem_resource descriptor: 0x%x," 432 " length: %d, space_id: %d, resource_usage: %d," 433 " type_specific: %d, granularity: 0x%llx," 434 " minimum: 0x%llx, maximum: 0x%llx," 435 " translation_offset: 0x%llx, address_length: 0x%llx\n", 436 mem_resource->descriptor, mem_resource->length, 437 mem_resource->space_id, mem_resource->resource_usage, 438 mem_resource->type_specific, mem_resource->granularity, 439 mem_resource->minimum, mem_resource->maximum, 440 mem_resource->translation_offset, 441 mem_resource->address_length); 442 443 if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) { 444 ret = -ENODEV; 445 goto out_free; 446 } 447 448 pcch_virt_addr = ioremap_nocache(mem_resource->minimum, 449 mem_resource->address_length); 450 if (pcch_virt_addr == NULL) { 451 pr_debug("probe: could not map shared mem region\n"); 452 ret = -ENOMEM; 453 goto out_free; 454 } 455 pcch_hdr = pcch_virt_addr; 456 457 pr_debug("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr); 458 pr_debug("probe: PCCH header is at physical address: 0x%llx," 459 " signature: 0x%x, length: %d bytes, major: %d, minor: %d," 460 " supported features: 0x%x, command field: 0x%x," 461 " status field: 0x%x, nominal latency: %d us\n", 462 mem_resource->minimum, ioread32(&pcch_hdr->signature), 463 ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major), 464 ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features), 465 ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status), 466 ioread32(&pcch_hdr->latency)); 467 468 pr_debug("probe: min time between commands: %d us," 469 " max time between commands: %d us," 470 " nominal CPU frequency: %d MHz," 471 " minimum CPU frequency: %d MHz," 472 " minimum CPU frequency without throttling: %d MHz\n", 473 ioread32(&pcch_hdr->minimum_time), 474 ioread32(&pcch_hdr->maximum_time), 475 ioread32(&pcch_hdr->nominal), 476 ioread32(&pcch_hdr->throttled_frequency), 477 ioread32(&pcch_hdr->minimum_frequency)); 478 479 member = &out_obj->package.elements[1]; 480 if (member->type != ACPI_TYPE_BUFFER) { 481 ret = -ENODEV; 482 goto pcch_free; 483 } 484 485 reg_resource = (struct pcc_register_resource *)member->buffer.pointer; 486 487 doorbell.space_id = reg_resource->space_id; 488 doorbell.bit_width = reg_resource->bit_width; 489 doorbell.bit_offset = reg_resource->bit_offset; 490 doorbell.access_width = 4; 491 doorbell.address = reg_resource->address; 492 493 pr_debug("probe: doorbell: space_id is %d, bit_width is %d, " 494 "bit_offset is %d, access_width is %d, address is 0x%llx\n", 495 doorbell.space_id, doorbell.bit_width, doorbell.bit_offset, 496 doorbell.access_width, reg_resource->address); 497 498 member = &out_obj->package.elements[2]; 499 if (member->type != ACPI_TYPE_INTEGER) { 500 ret = -ENODEV; 501 goto pcch_free; 502 } 503 504 doorbell_preserve = member->integer.value; 505 506 member = &out_obj->package.elements[3]; 507 if (member->type != ACPI_TYPE_INTEGER) { 508 ret = -ENODEV; 509 goto pcch_free; 510 } 511 512 doorbell_write = member->integer.value; 513 514 pr_debug("probe: doorbell_preserve: 0x%llx," 515 " doorbell_write: 0x%llx\n", 516 doorbell_preserve, doorbell_write); 517 518 pcc_cpu_info = alloc_percpu(struct pcc_cpu); 519 if (!pcc_cpu_info) { 520 ret = -ENOMEM; 521 goto pcch_free; 522 } 523 524 printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency" 525 " limits: %d MHz, %d MHz\n", PCC_VERSION, 526 ioread32(&pcch_hdr->minimum_frequency), 527 ioread32(&pcch_hdr->nominal)); 528 kfree(output.pointer); 529 return ret; 530 pcch_free: 531 pcc_clear_mapping(); 532 out_free: 533 kfree(output.pointer); 534 return ret; 535 } 536 537 static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy) 538 { 539 unsigned int cpu = policy->cpu; 540 unsigned int result = 0; 541 542 if (!pcch_virt_addr) { 543 result = -1; 544 goto out; 545 } 546 547 result = pcc_get_offset(cpu); 548 if (result) { 549 pr_debug("init: PCCP evaluation failed\n"); 550 goto out; 551 } 552 553 policy->max = policy->cpuinfo.max_freq = 554 ioread32(&pcch_hdr->nominal) * 1000; 555 policy->min = policy->cpuinfo.min_freq = 556 ioread32(&pcch_hdr->minimum_frequency) * 1000; 557 558 pr_debug("init: policy->max is %d, policy->min is %d\n", 559 policy->max, policy->min); 560 out: 561 return result; 562 } 563 564 static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy) 565 { 566 return 0; 567 } 568 569 static struct cpufreq_driver pcc_cpufreq_driver = { 570 .flags = CPUFREQ_CONST_LOOPS, 571 .get = pcc_get_freq, 572 .verify = pcc_cpufreq_verify, 573 .target = pcc_cpufreq_target, 574 .init = pcc_cpufreq_cpu_init, 575 .exit = pcc_cpufreq_cpu_exit, 576 .name = "pcc-cpufreq", 577 }; 578 579 static int __init pcc_cpufreq_init(void) 580 { 581 int ret; 582 583 /* Skip initialization if another cpufreq driver is there. */ 584 if (cpufreq_get_current_driver()) 585 return 0; 586 587 if (acpi_disabled) 588 return 0; 589 590 ret = pcc_cpufreq_probe(); 591 if (ret) { 592 pr_debug("pcc_cpufreq_init: PCCH evaluation failed\n"); 593 return ret; 594 } 595 596 if (num_present_cpus() > 4) { 597 pcc_cpufreq_driver.flags |= CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING; 598 pr_err("%s: Too many CPUs, dynamic performance scaling disabled\n", 599 __func__); 600 pr_err("%s: Try to enable another scaling driver through BIOS settings\n", 601 __func__); 602 pr_err("%s: and complain to the system vendor\n", __func__); 603 } 604 605 ret = cpufreq_register_driver(&pcc_cpufreq_driver); 606 607 return ret; 608 } 609 610 static void __exit pcc_cpufreq_exit(void) 611 { 612 cpufreq_unregister_driver(&pcc_cpufreq_driver); 613 614 pcc_clear_mapping(); 615 616 free_percpu(pcc_cpu_info); 617 } 618 619 static const struct acpi_device_id processor_device_ids[] = { 620 {ACPI_PROCESSOR_OBJECT_HID, }, 621 {ACPI_PROCESSOR_DEVICE_HID, }, 622 {}, 623 }; 624 MODULE_DEVICE_TABLE(acpi, processor_device_ids); 625 626 MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar"); 627 MODULE_VERSION(PCC_VERSION); 628 MODULE_DESCRIPTION("Processor Clocking Control interface driver"); 629 MODULE_LICENSE("GPL"); 630 631 late_initcall(pcc_cpufreq_init); 632 module_exit(pcc_cpufreq_exit); 633