arch/x86/kernel/cpu/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
  34 #include <linux/acpi.h>
  35 #include <linux/io.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/uaccess.h>
  38
  39 #include <acpi/processor.h>
  40
  41 #define PCC_VERSION     "1.00.00"
  42 #define POLL_LOOPS      300
  43
  44 #define CMD_COMPLETE    0x1
  45 #define CMD_GET_FREQ    0x0
  46 #define CMD_SET_FREQ    0x1
  47
  48 #define BUF_SZ          4
  49
  50 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER,      \
  51                                              "pcc-cpufreq", msg)
  52
  53 struct pcc_register_resource {
  54         u8 descriptor;
  55         u16 length;
  56         u8 space_id;
  57         u8 bit_width;
  58         u8 bit_offset;
  59         u8 access_size;
  60         u64 address;
  61 } __attribute__ ((packed));
  62
  63 struct pcc_memory_resource {
  64         u8 descriptor;
  65         u16 length;
  66         u8 space_id;
  67         u8 resource_usage;
  68         u8 type_specific;
  69         u64 granularity;
  70         u64 minimum;
  71         u64 maximum;
  72         u64 translation_offset;
  73         u64 address_length;
  74 } __attribute__ ((packed));
  75
  76 static struct cpufreq_driver pcc_cpufreq_driver;
  77
  78 struct pcc_header {
  79         u32 signature;
  80         u16 length;
  81         u8 major;
  82         u8 minor;
  83         u32 features;
  84         u16 command;
  85         u16 status;
  86         u32 latency;
  87         u32 minimum_time;
  88         u32 maximum_time;
  89         u32 nominal;
  90         u32 throttled_frequency;
  91         u32 minimum_frequency;
  92 };
  93
  94 static void __iomem *pcch_virt_addr;
  95 static struct pcc_header __iomem *pcch_hdr;
  96
  97 static DEFINE_SPINLOCK(pcc_lock);
  98
  99 static struct acpi_generic_address doorbell;
 100
 101 static u64 doorbell_preserve;
 102 static u64 doorbell_write;
 103
 104 static u8 OSC_UUID[16] = {0x63, 0x9B, 0x2C, 0x9F, 0x70, 0x91, 0x49, 0x1f,
 105                           0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
 106
 107 struct pcc_cpu {
 108         u32 input_offset;
 109         u32 output_offset;
 110 };
 111
 112 static struct pcc_cpu *pcc_cpu_info;
 113
 114 static int pcc_cpufreq_verify(struct cpufreq_policy *policy)
 115 {
 116         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
 117                                      policy->cpuinfo.max_freq);
 118         return 0;
 119 }
 120
 121 static inline void pcc_cmd(void)
 122 {
 123         u64 doorbell_value;
 124         int i;
 125
 126         acpi_read(&doorbell_value, &doorbell);
 127         acpi_write((doorbell_value & doorbell_preserve) | doorbell_write,
 128                    &doorbell);
 129
 130         for (i = 0; i < POLL_LOOPS; i++) {
 131                 if (ioread16(&pcch_hdr->status) & CMD_COMPLETE)
 132                         break;
 133         }
 134 }
 135
 136 static inline void pcc_clear_mapping(void)
 137 {
 138         if (pcch_virt_addr)
 139                 iounmap(pcch_virt_addr);
 140         pcch_virt_addr = NULL;
 141 }
 142
 143 static unsigned int pcc_get_freq(unsigned int cpu)
 144 {
 145         struct pcc_cpu *pcc_cpu_data;
 146         unsigned int curr_freq;
 147         unsigned int freq_limit;
 148         u16 status;
 149         u32 input_buffer;
 150         u32 output_buffer;
 151
 152         spin_lock(&pcc_lock);
 153
 154         dprintk("get: get_freq for CPU %d\n", cpu);
 155         pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
 156
 157         input_buffer = 0x1;
 158         iowrite32(input_buffer,
 159                         (pcch_virt_addr + pcc_cpu_data->input_offset));
 160         iowrite16(CMD_GET_FREQ, &pcch_hdr->command);
 161
 162         pcc_cmd();
 163
 164         output_buffer =
 165                 ioread32(pcch_virt_addr + pcc_cpu_data->output_offset);
 166
 167         /* Clear the input buffer - we are done with the current command */
 168         memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
 169
 170         status = ioread16(&pcch_hdr->status);
 171         if (status != CMD_COMPLETE) {
 172                 dprintk("get: FAILED: for CPU %d, status is %d\n",
 173                         cpu, status);
 174                 goto cmd_incomplete;
 175         }
 176         iowrite16(0, &pcch_hdr->status);
 177         curr_freq = (((ioread32(&pcch_hdr->nominal) * (output_buffer & 0xff))
 178                         / 100) * 1000);
 179
 180         dprintk("get: SUCCESS: (virtual) output_offset for cpu %d is "
 181                 "0x%x, contains a value of: 0x%x. Speed is: %d MHz\n",
 182                 cpu, (pcch_virt_addr + pcc_cpu_data->output_offset),
 183                 output_buffer, curr_freq);
 184
 185         freq_limit = (output_buffer >> 8) & 0xff;
 186         if (freq_limit != 0xff) {
 187                 dprintk("get: frequency for cpu %d is being temporarily"
 188                         " capped at %d\n", cpu, curr_freq);
 189         }
 190
 191         spin_unlock(&pcc_lock);
 192         return curr_freq;
 193
 194 cmd_incomplete:
 195         iowrite16(0, &pcch_hdr->status);
 196         spin_unlock(&pcc_lock);
 197         return -EINVAL;
 198 }
 199
 200 static int pcc_cpufreq_target(struct cpufreq_policy *policy,
 201                               unsigned int target_freq,
 202                               unsigned int relation)
 203 {
 204         struct pcc_cpu *pcc_cpu_data;
 205         struct cpufreq_freqs freqs;
 206         u16 status;
 207         u32 input_buffer;
 208         int cpu;
 209
 210         spin_lock(&pcc_lock);
 211         cpu = policy->cpu;
 212         pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
 213
 214         dprintk("target: CPU %d should go to target freq: %d "
 215                 "(virtual) input_offset is 0x%x\n",
 216                 cpu, target_freq,
 217                 (pcch_virt_addr + pcc_cpu_data->input_offset));
 218
 219         freqs.new = target_freq;
 220         freqs.cpu = cpu;
 221         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 222
 223         input_buffer = 0x1 | (((target_freq * 100)
 224                                / (ioread32(&pcch_hdr->nominal) * 1000)) << 8);
 225         iowrite32(input_buffer,
 226                         (pcch_virt_addr + pcc_cpu_data->input_offset));
 227         iowrite16(CMD_SET_FREQ, &pcch_hdr->command);
 228
 229         pcc_cmd();
 230
 231         /* Clear the input buffer - we are done with the current command */
 232         memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
 233
 234         status = ioread16(&pcch_hdr->status);
 235         if (status != CMD_COMPLETE) {
 236                 dprintk("target: FAILED for cpu %d, with status: 0x%x\n",
 237                         cpu, status);
 238                 goto cmd_incomplete;
 239         }
 240         iowrite16(0, &pcch_hdr->status);
 241
 242         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 243         dprintk("target: was SUCCESSFUL for cpu %d\n", cpu);
 244         spin_unlock(&pcc_lock);
 245
 246         return 0;
 247
 248 cmd_incomplete:
 249         iowrite16(0, &pcch_hdr->status);
 250         spin_unlock(&pcc_lock);
 251         return -EINVAL;
 252 }
 253
 254 static int pcc_get_offset(int cpu)
 255 {
 256         acpi_status status;
 257         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 258         union acpi_object *pccp, *offset;
 259         struct pcc_cpu *pcc_cpu_data;
 260         struct acpi_processor *pr;
 261         int ret = 0;
 262
 263         pr = per_cpu(processors, cpu);
 264         pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
 265
 266         status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer);
 267         if (ACPI_FAILURE(status))
 268                 return -ENODEV;
 269
 270         pccp = buffer.pointer;
 271         if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) {
 272                 ret = -ENODEV;
 273                 goto out_free;
 274         };
 275
 276         offset = &(pccp->package.elements[0]);
 277         if (!offset || offset->type != ACPI_TYPE_INTEGER) {
 278                 ret = -ENODEV;
 279                 goto out_free;
 280         }
 281
 282         pcc_cpu_data->input_offset = offset->integer.value;
 283
 284         offset = &(pccp->package.elements[1]);
 285         if (!offset || offset->type != ACPI_TYPE_INTEGER) {
 286                 ret = -ENODEV;
 287                 goto out_free;
 288         }
 289
 290         pcc_cpu_data->output_offset = offset->integer.value;
 291
 292         memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
 293         memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ);
 294
 295         dprintk("pcc_get_offset: for CPU %d: pcc_cpu_data "
 296                 "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n",
 297                 cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset);
 298 out_free:
 299         kfree(buffer.pointer);
 300         return ret;
 301 }
 302
 303 static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
 304 {
 305         acpi_status status;
 306         struct acpi_object_list input;
 307         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 308         union acpi_object in_params[4];
 309         union acpi_object *out_obj;
 310         u32 capabilities[2];
 311         u32 errors;
 312         u32 supported;
 313         int ret = 0;
 314
 315         input.count = 4;
 316         input.pointer = in_params;
 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         status = acpi_get_handle(handle, "_OSC", &osc_handle);
 407         if (ACPI_SUCCESS(status)) {
 408                 ret = pcc_cpufreq_do_osc(&osc_handle);
 409                 if (ret)
 410                         dprintk("probe: _OSC evaluation did not succeed\n");
 411                 /* Firmware's use of _OSC is optional */
 412                 ret = 0;
 413         }
 414
 415         status = acpi_evaluate_object(handle, "PCCH", NULL, &output);
 416         if (ACPI_FAILURE(status))
 417                 return -ENODEV;
 418
 419         out_obj = output.pointer;
 420         if (out_obj->type != ACPI_TYPE_PACKAGE) {
 421                 ret = -ENODEV;
 422                 goto out_free;
 423         }
 424
 425         member = &out_obj->package.elements[0];
 426         if (member->type != ACPI_TYPE_BUFFER) {
 427                 ret = -ENODEV;
 428                 goto out_free;
 429         }
 430
 431         mem_resource = (struct pcc_memory_resource *)member->buffer.pointer;
 432
 433         dprintk("probe: mem_resource descriptor: 0x%x,"
 434                 " length: %d, space_id: %d, resource_usage: %d,"
 435                 " type_specific: %d, granularity: 0x%llx,"
 436                 " minimum: 0x%llx, maximum: 0x%llx,"
 437                 " translation_offset: 0x%llx, address_length: 0x%llx\n",
 438                 mem_resource->descriptor, mem_resource->length,
 439                 mem_resource->space_id, mem_resource->resource_usage,
 440                 mem_resource->type_specific, mem_resource->granularity,
 441                 mem_resource->minimum, mem_resource->maximum,
 442                 mem_resource->translation_offset,
 443                 mem_resource->address_length);
 444
 445         if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 446                 ret = -ENODEV;
 447                 goto out_free;
 448         }
 449
 450         pcch_virt_addr = ioremap_nocache(mem_resource->minimum,
 451                                         mem_resource->address_length);
 452         if (pcch_virt_addr == NULL) {
 453                 dprintk("probe: could not map shared mem region\n");
 454                 goto out_free;
 455         }
 456         pcch_hdr = pcch_virt_addr;
 457
 458         dprintk("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr);
 459         dprintk("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         dprintk("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 = 64;
 492         doorbell.address = reg_resource->address;
 493
 494         dprintk("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         dprintk("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 pcch_null;
 546         }
 547
 548         result = pcc_get_offset(cpu);
 549         if (result) {
 550                 dprintk("init: PCCP evaluation failed\n");
 551                 goto free;
 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         policy->cur = pcc_get_freq(cpu);
 559
 560         dprintk("init: policy->max is %d, policy->min is %d\n",
 561                 policy->max, policy->min);
 562
 563         return 0;
 564 free:
 565         pcc_clear_mapping();
 566         free_percpu(pcc_cpu_info);
 567 pcch_null:
 568         return result;
 569 }
 570
 571 static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 572 {
 573         return 0;
 574 }
 575
 576 static struct cpufreq_driver pcc_cpufreq_driver = {
 577         .flags = CPUFREQ_CONST_LOOPS,
 578         .get = pcc_get_freq,
 579         .verify = pcc_cpufreq_verify,
 580         .target = pcc_cpufreq_target,
 581         .init = pcc_cpufreq_cpu_init,
 582         .exit = pcc_cpufreq_cpu_exit,
 583         .name = "pcc-cpufreq",
 584         .owner = THIS_MODULE,
 585 };
 586
 587 static int __init pcc_cpufreq_init(void)
 588 {
 589         int ret;
 590
 591         if (acpi_disabled)
 592                 return 0;
 593
 594         ret = pcc_cpufreq_probe();
 595         if (ret) {
 596                 dprintk("pcc_cpufreq_init: PCCH evaluation failed\n");
 597                 return ret;
 598         }
 599
 600         ret = cpufreq_register_driver(&pcc_cpufreq_driver);
 601
 602         return ret;
 603 }
 604
 605 static void __exit pcc_cpufreq_exit(void)
 606 {
 607         cpufreq_unregister_driver(&pcc_cpufreq_driver);
 608
 609         pcc_clear_mapping();
 610
 611         free_percpu(pcc_cpu_info);
 612 }
 613
 614 MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
 615 MODULE_VERSION(PCC_VERSION);
 616 MODULE_DESCRIPTION("Processor Clocking Control interface driver");
 617 MODULE_LICENSE("GPL");
 618
 619 late_initcall(pcc_cpufreq_init);
 620 module_exit(pcc_cpufreq_exit);