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_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         spin_lock(&pcc_lock);
 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.new = target_freq;
 217         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 218
 219         input_buffer = 0x1 | (((target_freq * 100)
 220                                / (ioread32(&pcch_hdr->nominal) * 1000)) << 8);
 221         iowrite32(input_buffer,
 222                         (pcch_virt_addr + pcc_cpu_data->input_offset));
 223         iowrite16(CMD_SET_FREQ, &pcch_hdr->command);
 224
 225         pcc_cmd();
 226
 227         /* Clear the input buffer - we are done with the current command */
 228         memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
 229
 230         status = ioread16(&pcch_hdr->status);
 231         if (status != CMD_COMPLETE) {
 232                 pr_debug("target: FAILED for cpu %d, with status: 0x%x\n",
 233                         cpu, status);
 234                 goto cmd_incomplete;
 235         }
 236         iowrite16(0, &pcch_hdr->status);
 237
 238         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 239         pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu);
 240         spin_unlock(&pcc_lock);
 241
 242         return 0;
 243
 244 cmd_incomplete:
 245         freqs.new = freqs.old;
 246         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 247         iowrite16(0, &pcch_hdr->status);
 248         spin_unlock(&pcc_lock);
 249         return -EINVAL;
 250 }
 251
 252 static 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);
 299 out_free:
 300         kfree(buffer.pointer);
 301         return ret;
 302 }
 303
 304 static 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
 386 out_free:
 387         kfree(output.pointer);
 388         return ret;
 389 }
 390
 391 static 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;
 399         int ret = 0;
 400
 401         status = acpi_get_handle(NULL, "\\_SB", &handle);
 402         if (ACPI_FAILURE(status))
 403                 return -ENODEV;
 404
 405         if (!acpi_has_method(handle, "PCCH"))
 406                 return -ENODEV;
 407
 408         status = acpi_get_handle(handle, "_OSC", &osc_handle);
 409         if (ACPI_SUCCESS(status)) {
 410                 ret = pcc_cpufreq_do_osc(&osc_handle);
 411                 if (ret)
 412                         pr_debug("probe: _OSC evaluation did not succeed\n");
 413                 /* Firmware's use of _OSC is optional */
 414                 ret = 0;
 415         }
 416
 417         status = acpi_evaluate_object(handle, "PCCH", NULL, &output);
 418         if (ACPI_FAILURE(status))
 419                 return -ENODEV;
 420
 421         out_obj = output.pointer;
 422         if (out_obj->type != ACPI_TYPE_PACKAGE) {
 423                 ret = -ENODEV;
 424                 goto out_free;
 425         }
 426
 427         member = &out_obj->package.elements[0];
 428         if (member->type != ACPI_TYPE_BUFFER) {
 429                 ret = -ENODEV;
 430                 goto out_free;
 431         }
 432
 433         mem_resource = (struct pcc_memory_resource *)member->buffer.pointer;
 434
 435         pr_debug("probe: mem_resource descriptor: 0x%x,"
 436                 " length: %d, space_id: %d, resource_usage: %d,"
 437                 " type_specific: %d, granularity: 0x%llx,"
 438                 " minimum: 0x%llx, maximum: 0x%llx,"
 439                 " translation_offset: 0x%llx, address_length: 0x%llx\n",
 440                 mem_resource->descriptor, mem_resource->length,
 441                 mem_resource->space_id, mem_resource->resource_usage,
 442                 mem_resource->type_specific, mem_resource->granularity,
 443                 mem_resource->minimum, mem_resource->maximum,
 444                 mem_resource->translation_offset,
 445                 mem_resource->address_length);
 446
 447         if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 448                 ret = -ENODEV;
 449                 goto out_free;
 450         }
 451
 452         pcch_virt_addr = ioremap_nocache(mem_resource->minimum,
 453                                         mem_resource->address_length);
 454         if (pcch_virt_addr == NULL) {
 455                 pr_debug("probe: could not map shared mem region\n");
 456                 ret = -ENOMEM;
 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;
 534 pcch_free:
 535         pcc_clear_mapping();
 536 out_free:
 537         kfree(output.pointer);
 538         return ret;
 539 }
 540
 541 static 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
 562         pr_debug("init: policy->max is %d, policy->min is %d\n",
 563                 policy->max, policy->min);
 564 out:
 565         return result;
 566 }
 567
 568 static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 569 {
 570         return 0;
 571 }
 572
 573 static struct cpufreq_driver pcc_cpufreq_driver = {
 574         .flags = CPUFREQ_CONST_LOOPS,
 575         .get = pcc_get_freq,
 576         .verify = pcc_cpufreq_verify,
 577         .target = pcc_cpufreq_target,
 578         .init = pcc_cpufreq_cpu_init,
 579         .exit = pcc_cpufreq_cpu_exit,
 580         .name = "pcc-cpufreq",
 581 };
 582
 583 static int __init pcc_cpufreq_init(void)
 584 {
 585         int ret;
 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         ret = cpufreq_register_driver(&pcc_cpufreq_driver);
 597
 598         return ret;
 599 }
 600
 601 static void __exit pcc_cpufreq_exit(void)
 602 {
 603         cpufreq_unregister_driver(&pcc_cpufreq_driver);
 604
 605         pcc_clear_mapping();
 606
 607         free_percpu(pcc_cpu_info);
 608 }
 609
 610 MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
 611 MODULE_VERSION(PCC_VERSION);
 612 MODULE_DESCRIPTION("Processor Clocking Control interface driver");
 613 MODULE_LICENSE("GPL");
 614
 615 late_initcall(pcc_cpufreq_init);
 616 module_exit(pcc_cpufreq_exit);