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   1 /*
   2  * arch/ia64/kernel/cpufreq/acpi-cpufreq.c
   3  * This file provides the ACPI based P-state support. This
   4  * module works with generic cpufreq infrastructure. Most of
   5  * the code is based on i386 version
   6  * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
   7  *
   8  * Copyright (C) 2005 Intel Corp
   9  *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/cpufreq.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/seq_file.h>
  19 #include <asm/io.h>
  20 #include <asm/uaccess.h>
  21 #include <asm/pal.h>
  22
  23 #include <linux/acpi.h>
  24 #include <acpi/processor.h>
  25
  26 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
  27
  28 MODULE_AUTHOR("Venkatesh Pallipadi");
  29 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  30 MODULE_LICENSE("GPL");
  31
  32
  33 struct cpufreq_acpi_io {
  34         struct acpi_processor_performance       acpi_data;
  35         struct cpufreq_frequency_table          *freq_table;
  36         unsigned int                            resume;
  37 };
  38
  39 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
  40
  41 static struct cpufreq_driver acpi_cpufreq_driver;
  42
  43
  44 static int
  45 processor_set_pstate (
  46         u32     value)
  47 {
  48         s64 retval;
  49
  50         dprintk("processor_set_pstate\n");
  51
  52         retval = ia64_pal_set_pstate((u64)value);
  53
  54         if (retval) {
  55                 dprintk("Failed to set freq to 0x%x, with error 0x%x\n",
  56                         value, retval);
  57                 return -ENODEV;
  58         }
  59         return (int)retval;
  60 }
  61
  62
  63 static int
  64 processor_get_pstate (
  65         u32     *value)
  66 {
  67         u64     pstate_index = 0;
  68         s64     retval;
  69
  70         dprintk("processor_get_pstate\n");
  71
  72         retval = ia64_pal_get_pstate(&pstate_index);
  73         *value = (u32) pstate_index;
  74
  75         if (retval)
  76                 dprintk("Failed to get current freq with "
  77                         "error 0x%x, idx 0x%x\n", retval, *value);
  78
  79         return (int)retval;
  80 }
  81
  82
  83 /* To be used only after data->acpi_data is initialized */
  84 static unsigned
  85 extract_clock (
  86         struct cpufreq_acpi_io *data,
  87         unsigned value,
  88         unsigned int cpu)
  89 {
  90         unsigned long i;
  91
  92         dprintk("extract_clock\n");
  93
  94         for (i = 0; i < data->acpi_data.state_count; i++) {
  95                 if (value >= data->acpi_data.states[i].control)
  96                         return data->acpi_data.states[i].core_frequency;
  97         }
  98         return data->acpi_data.states[i-1].core_frequency;
  99 }
 100
 101
 102 static unsigned int
 103 processor_get_freq (
 104         struct cpufreq_acpi_io  *data,
 105         unsigned int            cpu)
 106 {
 107         int                     ret = 0;
 108         u32                     value = 0;
 109         cpumask_t               saved_mask;
 110         unsigned long           clock_freq;
 111
 112         dprintk("processor_get_freq\n");
 113
 114         saved_mask = current->cpus_allowed;
 115         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 116         if (smp_processor_id() != cpu) {
 117                 ret = -EAGAIN;
 118                 goto migrate_end;
 119         }
 120
 121         /*
 122          * processor_get_pstate gets the average frequency since the
 123          * last get. So, do two PAL_get_freq()...
 124          */
 125         ret = processor_get_pstate(&value);
 126         ret = processor_get_pstate(&value);
 127
 128         if (ret) {
 129                 set_cpus_allowed(current, saved_mask);
 130                 printk(KERN_WARNING "get performance failed with error %d\n",
 131                        ret);
 132                 ret = -EAGAIN;
 133                 goto migrate_end;
 134         }
 135         clock_freq = extract_clock(data, value, cpu);
 136         ret = (clock_freq*1000);
 137
 138 migrate_end:
 139         set_cpus_allowed(current, saved_mask);
 140         return ret;
 141 }
 142
 143
 144 static int
 145 processor_set_freq (
 146         struct cpufreq_acpi_io  *data,
 147         unsigned int            cpu,
 148         int                     state)
 149 {
 150         int                     ret = 0;
 151         u32                     value = 0;
 152         struct cpufreq_freqs    cpufreq_freqs;
 153         cpumask_t               saved_mask;
 154         int                     retval;
 155
 156         dprintk("processor_set_freq\n");
 157
 158         saved_mask = current->cpus_allowed;
 159         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 160         if (smp_processor_id() != cpu) {
 161                 retval = -EAGAIN;
 162                 goto migrate_end;
 163         }
 164
 165         if (state == data->acpi_data.state) {
 166                 if (unlikely(data->resume)) {
 167                         dprintk("Called after resume, resetting to P%d\n", state);
 168                         data->resume = 0;
 169                 } else {
 170                         dprintk("Already at target state (P%d)\n", state);
 171                         retval = 0;
 172                         goto migrate_end;
 173                 }
 174         }
 175
 176         dprintk("Transitioning from P%d to P%d\n",
 177                 data->acpi_data.state, state);
 178
 179         /* cpufreq frequency struct */
 180         cpufreq_freqs.cpu = cpu;
 181         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
 182         cpufreq_freqs.new = data->freq_table[state].frequency;
 183
 184         /* notify cpufreq */
 185         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 186
 187         /*
 188          * First we write the target state's 'control' value to the
 189          * control_register.
 190          */
 191
 192         value = (u32) data->acpi_data.states[state].control;
 193
 194         dprintk("Transitioning to state: 0x%08x\n", value);
 195
 196         ret = processor_set_pstate(value);
 197         if (ret) {
 198                 unsigned int tmp = cpufreq_freqs.new;
 199                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 200                 cpufreq_freqs.new = cpufreq_freqs.old;
 201                 cpufreq_freqs.old = tmp;
 202                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 203                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 204                 printk(KERN_WARNING "Transition failed with error %d\n", ret);
 205                 retval = -ENODEV;
 206                 goto migrate_end;
 207         }
 208
 209         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 210
 211         data->acpi_data.state = state;
 212
 213         retval = 0;
 214
 215 migrate_end:
 216         set_cpus_allowed(current, saved_mask);
 217         return (retval);
 218 }
 219
 220
 221 static unsigned int
 222 acpi_cpufreq_get (
 223         unsigned int            cpu)
 224 {
 225         struct cpufreq_acpi_io *data = acpi_io_data[cpu];
 226
 227         dprintk("acpi_cpufreq_get\n");
 228
 229         return processor_get_freq(data, cpu);
 230 }
 231
 232
 233 static int
 234 acpi_cpufreq_target (
 235         struct cpufreq_policy   *policy,
 236         unsigned int target_freq,
 237         unsigned int relation)
 238 {
 239         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 240         unsigned int next_state = 0;
 241         unsigned int result = 0;
 242
 243         dprintk("acpi_cpufreq_setpolicy\n");
 244
 245         result = cpufreq_frequency_table_target(policy,
 246                         data->freq_table, target_freq, relation, &next_state);
 247         if (result)
 248                 return (result);
 249
 250         result = processor_set_freq(data, policy->cpu, next_state);
 251
 252         return (result);
 253 }
 254
 255
 256 static int
 257 acpi_cpufreq_verify (
 258         struct cpufreq_policy   *policy)
 259 {
 260         unsigned int result = 0;
 261         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 262
 263         dprintk("acpi_cpufreq_verify\n");
 264
 265         result = cpufreq_frequency_table_verify(policy,
 266                         data->freq_table);
 267
 268         return (result);
 269 }
 270
 271
 272 /*
 273  * processor_init_pdc - let BIOS know about the SMP capabilities
 274  * of this driver
 275  * @perf: processor-specific acpi_io_data struct
 276  * @cpu: CPU being initialized
 277  *
 278  * To avoid issues with legacy OSes, some BIOSes require to be informed of
 279  * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC
 280  * accordingly. Actual call to _PDC is done in driver/acpi/processor.c
 281  */
 282 static void
 283 processor_init_pdc (
 284                 struct acpi_processor_performance *perf,
 285                 unsigned int cpu,
 286                 struct acpi_object_list *obj_list
 287                 )
 288 {
 289         union acpi_object *obj;
 290         u32 *buf;
 291
 292         dprintk("processor_init_pdc\n");
 293
 294         perf->pdc = NULL;
 295         /* Initialize pdc. It will be used later. */
 296         if (!obj_list)
 297                 return;
 298
 299         if (!(obj_list->count && obj_list->pointer))
 300                 return;
 301
 302         obj = obj_list->pointer;
 303         if ((obj->buffer.length == 12) && obj->buffer.pointer) {
 304                 buf = (u32 *)obj->buffer.pointer;
 305                 buf[0] = ACPI_PDC_REVISION_ID;
 306                 buf[1] = 1;
 307                 buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;
 308                 perf->pdc = obj_list;
 309         }
 310         return;
 311 }
 312
 313
 314 static int
 315 acpi_cpufreq_cpu_init (
 316         struct cpufreq_policy   *policy)
 317 {
 318         unsigned int            i;
 319         unsigned int            cpu = policy->cpu;
 320         struct cpufreq_acpi_io  *data;
 321         unsigned int            result = 0;
 322
 323         union acpi_object               arg0 = {ACPI_TYPE_BUFFER};
 324         u32                             arg0_buf[3];
 325         struct acpi_object_list         arg_list = {1, &arg0};
 326
 327         dprintk("acpi_cpufreq_cpu_init\n");
 328         /* setup arg_list for _PDC settings */
 329         arg0.buffer.length = 12;
 330         arg0.buffer.pointer = (u8 *) arg0_buf;
 331
 332         data = kmalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 333         if (!data)
 334                 return (-ENOMEM);
 335
 336         memset(data, 0, sizeof(struct cpufreq_acpi_io));
 337
 338         acpi_io_data[cpu] = data;
 339
 340         processor_init_pdc(&data->acpi_data, cpu, &arg_list);
 341         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 342         data->acpi_data.pdc = NULL;
 343
 344         if (result)
 345                 goto err_free;
 346
 347         /* capability check */
 348         if (data->acpi_data.state_count <= 1) {
 349                 dprintk("No P-States\n");
 350                 result = -ENODEV;
 351                 goto err_unreg;
 352         }
 353
 354         if ((data->acpi_data.control_register.space_id !=
 355                                         ACPI_ADR_SPACE_FIXED_HARDWARE) ||
 356             (data->acpi_data.status_register.space_id !=
 357                                         ACPI_ADR_SPACE_FIXED_HARDWARE)) {
 358                 dprintk("Unsupported address space [%d, %d]\n",
 359                         (u32) (data->acpi_data.control_register.space_id),
 360                         (u32) (data->acpi_data.status_register.space_id));
 361                 result = -ENODEV;
 362                 goto err_unreg;
 363         }
 364
 365         /* alloc freq_table */
 366         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
 367                                    (data->acpi_data.state_count + 1),
 368                                    GFP_KERNEL);
 369         if (!data->freq_table) {
 370                 result = -ENOMEM;
 371                 goto err_unreg;
 372         }
 373
 374         /* detect transition latency */
 375         policy->cpuinfo.transition_latency = 0;
 376         for (i=0; i<data->acpi_data.state_count; i++) {
 377                 if ((data->acpi_data.states[i].transition_latency * 1000) >
 378                     policy->cpuinfo.transition_latency) {
 379                         policy->cpuinfo.transition_latency =
 380                             data->acpi_data.states[i].transition_latency * 1000;
 381                 }
 382         }
 383         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 384
 385         policy->cur = processor_get_freq(data, policy->cpu);
 386
 387         /* table init */
 388         for (i = 0; i <= data->acpi_data.state_count; i++)
 389         {
 390                 data->freq_table[i].index = i;
 391                 if (i < data->acpi_data.state_count) {
 392                         data->freq_table[i].frequency =
 393                               data->acpi_data.states[i].core_frequency * 1000;
 394                 } else {
 395                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 396                 }
 397         }
 398
 399         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 400         if (result) {
 401                 goto err_freqfree;
 402         }
 403
 404         /* notify BIOS that we exist */
 405         acpi_processor_notify_smm(THIS_MODULE);
 406
 407         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
 408                "activated.\n", cpu);
 409
 410         for (i = 0; i < data->acpi_data.state_count; i++)
 411                 dprintk("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
 412                         (i == data->acpi_data.state?'*':' '), i,
 413                         (u32) data->acpi_data.states[i].core_frequency,
 414                         (u32) data->acpi_data.states[i].power,
 415                         (u32) data->acpi_data.states[i].transition_latency,
 416                         (u32) data->acpi_data.states[i].bus_master_latency,
 417                         (u32) data->acpi_data.states[i].status,
 418                         (u32) data->acpi_data.states[i].control);
 419
 420         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 421
 422         /* the first call to ->target() should result in us actually
 423          * writing something to the appropriate registers. */
 424         data->resume = 1;
 425
 426         return (result);
 427
 428  err_freqfree:
 429         kfree(data->freq_table);
 430  err_unreg:
 431         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 432  err_free:
 433         kfree(data);
 434         acpi_io_data[cpu] = NULL;
 435
 436         return (result);
 437 }
 438
 439
 440 static int
 441 acpi_cpufreq_cpu_exit (
 442         struct cpufreq_policy   *policy)
 443 {
 444         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 445
 446         dprintk("acpi_cpufreq_cpu_exit\n");
 447
 448         if (data) {
 449                 cpufreq_frequency_table_put_attr(policy->cpu);
 450                 acpi_io_data[policy->cpu] = NULL;
 451                 acpi_processor_unregister_performance(&data->acpi_data,
 452                                                       policy->cpu);
 453                 kfree(data);
 454         }
 455
 456         return (0);
 457 }
 458
 459
 460 static struct freq_attr* acpi_cpufreq_attr[] = {
 461         &cpufreq_freq_attr_scaling_available_freqs,
 462         NULL,
 463 };
 464
 465
 466 static struct cpufreq_driver acpi_cpufreq_driver = {
 467         .verify         = acpi_cpufreq_verify,
 468         .target         = acpi_cpufreq_target,
 469         .get            = acpi_cpufreq_get,
 470         .init           = acpi_cpufreq_cpu_init,
 471         .exit           = acpi_cpufreq_cpu_exit,
 472         .name           = "acpi-cpufreq",
 473         .owner          = THIS_MODULE,
 474         .attr           = acpi_cpufreq_attr,
 475 };
 476
 477
 478 static int __init
 479 acpi_cpufreq_init (void)
 480 {
 481         dprintk("acpi_cpufreq_init\n");
 482
 483         return cpufreq_register_driver(&acpi_cpufreq_driver);
 484 }
 485
 486
 487 static void __exit
 488 acpi_cpufreq_exit (void)
 489 {
 490         dprintk("acpi_cpufreq_exit\n");
 491
 492         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 493         return;
 494 }
 495
 496
 497 late_initcall(acpi_cpufreq_init);
 498 module_exit(acpi_cpufreq_exit);
 499