drivers/cpufreq/pcc-cpufreq.c

   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_limits(policy, policy->cpuinfo.min_freq,
 115                                      policy->cpuinfo.max_freq);
 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         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         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 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         if (status != CMD_COMPLETE) {
 233                 pr_debug("target: FAILED for cpu %d, with status: 0x%x\n",
 234                         cpu, status);
 235                 goto cmd_incomplete;
 236         }
 237         iowrite16(0, &pcch_hdr->status);
 238
 239         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 240         pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu);
 241         spin_unlock(&pcc_lock);
 242
 243         return 0;
 244
 245 cmd_incomplete:
 246         freqs.new = freqs.old;
 247         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 248         iowrite16(0, &pcch_hdr->status);
 249         spin_unlock(&pcc_lock);
 250         return -EINVAL;
 251 }
 252
 253 static int pcc_get_offset(int cpu)
 254 {
 255         acpi_status status;
 256         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 257         union acpi_object *pccp, *offset;
 258         struct pcc_cpu *pcc_cpu_data;
 259         struct acpi_processor *pr;
 260         int ret = 0;
 261
 262         pr = per_cpu(processors, cpu);
 263         pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
 264
 265         if (!pr)
 266                 return -ENODEV;
 267
 268         status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer);
 269         if (ACPI_FAILURE(status))
 270                 return -ENODEV;
 271
 272         pccp = buffer.pointer;
 273         if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) {
 274                 ret = -ENODEV;
 275                 goto out_free;
 276         };
 277
 278         offset = &(pccp->package.elements[0]);
 279         if (!offset || offset->type != ACPI_TYPE_INTEGER) {
 280                 ret = -ENODEV;
 281                 goto out_free;
 282         }
 283
 284         pcc_cpu_data->input_offset = offset->integer.value;
 285
 286         offset = &(pccp->package.elements[1]);
 287         if (!offset || offset->type != ACPI_TYPE_INTEGER) {
 288                 ret = -ENODEV;
 289                 goto out_free;
 290         }
 291
 292         pcc_cpu_data->output_offset = offset->integer.value;
 293
 294         memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
 295         memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ);
 296
 297         pr_debug("pcc_get_offset: for CPU %d: pcc_cpu_data "
 298                 "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n",
 299                 cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset);
 300 out_free:
 301         kfree(buffer.pointer);
 302         return ret;
 303 }
 304
 305 static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
 306 {
 307         acpi_status status;
 308         struct acpi_object_list input;
 309         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 310         union acpi_object in_params[4];
 311         union acpi_object *out_obj;
 312         u32 capabilities[2];
 313         u32 errors;
 314         u32 supported;
 315         int ret = 0;
 316
 317         input.count = 4;
 318         input.pointer = in_params;
 319         in_params[0].type               = ACPI_TYPE_BUFFER;
 320         in_params[0].buffer.length      = 16;
 321         in_params[0].buffer.pointer     = OSC_UUID;
 322         in_params[1].type               = ACPI_TYPE_INTEGER;
 323         in_params[1].integer.value      = 1;
 324         in_params[2].type               = ACPI_TYPE_INTEGER;
 325         in_params[2].integer.value      = 2;
 326         in_params[3].type               = ACPI_TYPE_BUFFER;
 327         in_params[3].buffer.length      = 8;
 328         in_params[3].buffer.pointer     = (u8 *)&capabilities;
 329
 330         capabilities[0] = OSC_QUERY_ENABLE;
 331         capabilities[1] = 0x1;
 332
 333         status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
 334         if (ACPI_FAILURE(status))
 335                 return -ENODEV;
 336
 337         if (!output.length)
 338                 return -ENODEV;
 339
 340         out_obj = output.pointer;
 341         if (out_obj->type != ACPI_TYPE_BUFFER) {
 342                 ret = -ENODEV;
 343                 goto out_free;
 344         }
 345
 346         errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
 347         if (errors) {
 348                 ret = -ENODEV;
 349                 goto out_free;
 350         }
 351
 352         supported = *((u32 *)(out_obj->buffer.pointer + 4));
 353         if (!(supported & 0x1)) {
 354                 ret = -ENODEV;
 355                 goto out_free;
 356         }
 357
 358         kfree(output.pointer);
 359         capabilities[0] = 0x0;
 360         capabilities[1] = 0x1;
 361
 362         status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
 363         if (ACPI_FAILURE(status))
 364                 return -ENODEV;
 365
 366         if (!output.length)
 367                 return -ENODEV;
 368
 369         out_obj = output.pointer;
 370         if (out_obj->type != ACPI_TYPE_BUFFER) {
 371                 ret = -ENODEV;
 372                 goto out_free;
 373         }
 374
 375         errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
 376         if (errors) {
 377                 ret = -ENODEV;
 378                 goto out_free;
 379         }
 380
 381         supported = *((u32 *)(out_obj->buffer.pointer + 4));
 382         if (!(supported & 0x1)) {
 383                 ret = -ENODEV;
 384                 goto out_free;
 385         }
 386
 387 out_free:
 388         kfree(output.pointer);
 389         return ret;
 390 }
 391
 392 static int __init pcc_cpufreq_probe(void)
 393 {
 394         acpi_status status;
 395         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 396         struct pcc_memory_resource *mem_resource;
 397         struct pcc_register_resource *reg_resource;
 398         union acpi_object *out_obj, *member;
 399         acpi_handle handle, osc_handle;
 400         int ret = 0;
 401
 402         status = acpi_get_handle(NULL, "\\_SB", &handle);
 403         if (ACPI_FAILURE(status))
 404                 return -ENODEV;
 405
 406         if (!acpi_has_method(handle, "PCCH"))
 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                 ret = -ENOMEM;
 458                 goto out_free;
 459         }
 460         pcch_hdr = pcch_virt_addr;
 461
 462         pr_debug("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr);
 463         pr_debug("probe: PCCH header is at physical address: 0x%llx,"
 464                 " signature: 0x%x, length: %d bytes, major: %d, minor: %d,"
 465                 " supported features: 0x%x, command field: 0x%x,"
 466                 " status field: 0x%x, nominal latency: %d us\n",
 467                 mem_resource->minimum, ioread32(&pcch_hdr->signature),
 468                 ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major),
 469                 ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features),
 470                 ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status),
 471                 ioread32(&pcch_hdr->latency));
 472
 473         pr_debug("probe: min time between commands: %d us,"
 474                 " max time between commands: %d us,"
 475                 " nominal CPU frequency: %d MHz,"
 476                 " minimum CPU frequency: %d MHz,"
 477                 " minimum CPU frequency without throttling: %d MHz\n",
 478                 ioread32(&pcch_hdr->minimum_time),
 479                 ioread32(&pcch_hdr->maximum_time),
 480                 ioread32(&pcch_hdr->nominal),
 481                 ioread32(&pcch_hdr->throttled_frequency),
 482                 ioread32(&pcch_hdr->minimum_frequency));
 483
 484         member = &out_obj->package.elements[1];
 485         if (member->type != ACPI_TYPE_BUFFER) {
 486                 ret = -ENODEV;
 487                 goto pcch_free;
 488         }
 489
 490         reg_resource = (struct pcc_register_resource *)member->buffer.pointer;
 491
 492         doorbell.space_id = reg_resource->space_id;
 493         doorbell.bit_width = reg_resource->bit_width;
 494         doorbell.bit_offset = reg_resource->bit_offset;
 495         doorbell.access_width = 64;
 496         doorbell.address = reg_resource->address;
 497
 498         pr_debug("probe: doorbell: space_id is %d, bit_width is %d, "
 499                 "bit_offset is %d, access_width is %d, address is 0x%llx\n",
 500                 doorbell.space_id, doorbell.bit_width, doorbell.bit_offset,
 501                 doorbell.access_width, reg_resource->address);
 502
 503         member = &out_obj->package.elements[2];
 504         if (member->type != ACPI_TYPE_INTEGER) {
 505                 ret = -ENODEV;
 506                 goto pcch_free;
 507         }
 508
 509         doorbell_preserve = member->integer.value;
 510
 511         member = &out_obj->package.elements[3];
 512         if (member->type != ACPI_TYPE_INTEGER) {
 513                 ret = -ENODEV;
 514                 goto pcch_free;
 515         }
 516
 517         doorbell_write = member->integer.value;
 518
 519         pr_debug("probe: doorbell_preserve: 0x%llx,"
 520                 " doorbell_write: 0x%llx\n",
 521                 doorbell_preserve, doorbell_write);
 522
 523         pcc_cpu_info = alloc_percpu(struct pcc_cpu);
 524         if (!pcc_cpu_info) {
 525                 ret = -ENOMEM;
 526                 goto pcch_free;
 527         }
 528
 529         printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency"
 530                " limits: %d MHz, %d MHz\n", PCC_VERSION,
 531                ioread32(&pcch_hdr->minimum_frequency),
 532                ioread32(&pcch_hdr->nominal));
 533         kfree(output.pointer);
 534         return ret;
 535 pcch_free:
 536         pcc_clear_mapping();
 537 out_free:
 538         kfree(output.pointer);
 539         return ret;
 540 }
 541
 542 static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 543 {
 544         unsigned int cpu = policy->cpu;
 545         unsigned int result = 0;
 546
 547         if (!pcch_virt_addr) {
 548                 result = -1;
 549                 goto out;
 550         }
 551
 552         result = pcc_get_offset(cpu);
 553         if (result) {
 554                 pr_debug("init: PCCP evaluation failed\n");
 555                 goto out;
 556         }
 557
 558         policy->max = policy->cpuinfo.max_freq =
 559                 ioread32(&pcch_hdr->nominal) * 1000;
 560         policy->min = policy->cpuinfo.min_freq =
 561                 ioread32(&pcch_hdr->minimum_frequency) * 1000;
 562         policy->cur = pcc_get_freq(cpu);
 563
 564         if (!policy->cur) {
 565                 pr_debug("init: Unable to get current CPU frequency\n");
 566                 result = -EINVAL;
 567                 goto out;
 568         }
 569
 570         pr_debug("init: policy->max is %d, policy->min is %d\n",
 571                 policy->max, policy->min);
 572 out:
 573         return result;
 574 }
 575
 576 static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 577 {
 578         return 0;
 579 }
 580
 581 static struct cpufreq_driver pcc_cpufreq_driver = {
 582         .flags = CPUFREQ_CONST_LOOPS,
 583         .get = pcc_get_freq,
 584         .verify = pcc_cpufreq_verify,
 585         .target = pcc_cpufreq_target,
 586         .init = pcc_cpufreq_cpu_init,
 587         .exit = pcc_cpufreq_cpu_exit,
 588         .name = "pcc-cpufreq",
 589 };
 590
 591 static 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
 609 static 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
 618 MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
 619 MODULE_VERSION(PCC_VERSION);
 620 MODULE_DESCRIPTION("Processor Clocking Control interface driver");
 621 MODULE_LICENSE("GPL");
 622
 623 late_initcall(pcc_cpufreq_init);
 624 module_exit(pcc_cpufreq_exit);