arch/ia64/kernel/cpufreq/acpi-cpufreq.c

   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/kernel.h>
  13 #include <linux/slab.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 MODULE_AUTHOR("Venkatesh Pallipadi");
  27 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  28 MODULE_LICENSE("GPL");
  29
  30
  31 struct cpufreq_acpi_io {
  32         struct acpi_processor_performance       acpi_data;
  33         struct cpufreq_frequency_table          *freq_table;
  34         unsigned int                            resume;
  35 };
  36
  37 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
  38
  39 static struct cpufreq_driver acpi_cpufreq_driver;
  40
  41
  42 static int
  43 processor_set_pstate (
  44         u32     value)
  45 {
  46         s64 retval;
  47
  48         pr_debug("processor_set_pstate\n");
  49
  50         retval = ia64_pal_set_pstate((u64)value);
  51
  52         if (retval) {
  53                 pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n",
  54                         value, retval);
  55                 return -ENODEV;
  56         }
  57         return (int)retval;
  58 }
  59
  60
  61 static int
  62 processor_get_pstate (
  63         u32     *value)
  64 {
  65         u64     pstate_index = 0;
  66         s64     retval;
  67
  68         pr_debug("processor_get_pstate\n");
  69
  70         retval = ia64_pal_get_pstate(&pstate_index,
  71                                      PAL_GET_PSTATE_TYPE_INSTANT);
  72         *value = (u32) pstate_index;
  73
  74         if (retval)
  75                 pr_debug("Failed to get current freq with "
  76                         "error 0x%lx, idx 0x%x\n", retval, *value);
  77
  78         return (int)retval;
  79 }
  80
  81
  82 /* To be used only after data->acpi_data is initialized */
  83 static unsigned
  84 extract_clock (
  85         struct cpufreq_acpi_io *data,
  86         unsigned value,
  87         unsigned int cpu)
  88 {
  89         unsigned long i;
  90
  91         pr_debug("extract_clock\n");
  92
  93         for (i = 0; i < data->acpi_data.state_count; i++) {
  94                 if (value == data->acpi_data.states[i].status)
  95                         return data->acpi_data.states[i].core_frequency;
  96         }
  97         return data->acpi_data.states[i-1].core_frequency;
  98 }
  99
 100
 101 static unsigned int
 102 processor_get_freq (
 103         struct cpufreq_acpi_io  *data,
 104         unsigned int            cpu)
 105 {
 106         int                     ret = 0;
 107         u32                     value = 0;
 108         cpumask_t               saved_mask;
 109         unsigned long           clock_freq;
 110
 111         pr_debug("processor_get_freq\n");
 112
 113         saved_mask = current->cpus_allowed;
 114         set_cpus_allowed_ptr(current, cpumask_of(cpu));
 115         if (smp_processor_id() != cpu)
 116                 goto migrate_end;
 117
 118         /* processor_get_pstate gets the instantaneous frequency */
 119         ret = processor_get_pstate(&value);
 120
 121         if (ret) {
 122                 set_cpus_allowed_ptr(current, &saved_mask);
 123                 printk(KERN_WARNING "get performance failed with error %d\n",
 124                        ret);
 125                 ret = 0;
 126                 goto migrate_end;
 127         }
 128         clock_freq = extract_clock(data, value, cpu);
 129         ret = (clock_freq*1000);
 130
 131 migrate_end:
 132         set_cpus_allowed_ptr(current, &saved_mask);
 133         return ret;
 134 }
 135
 136
 137 static int
 138 processor_set_freq (
 139         struct cpufreq_acpi_io  *data,
 140         struct cpufreq_policy   *policy,
 141         int                     state)
 142 {
 143         int                     ret = 0;
 144         u32                     value = 0;
 145         struct cpufreq_freqs    cpufreq_freqs;
 146         cpumask_t               saved_mask;
 147         int                     retval;
 148
 149         pr_debug("processor_set_freq\n");
 150
 151         saved_mask = current->cpus_allowed;
 152         set_cpus_allowed_ptr(current, cpumask_of(policy->cpu));
 153         if (smp_processor_id() != policy->cpu) {
 154                 retval = -EAGAIN;
 155                 goto migrate_end;
 156         }
 157
 158         if (state == data->acpi_data.state) {
 159                 if (unlikely(data->resume)) {
 160                         pr_debug("Called after resume, resetting to P%d\n", state);
 161                         data->resume = 0;
 162                 } else {
 163                         pr_debug("Already at target state (P%d)\n", state);
 164                         retval = 0;
 165                         goto migrate_end;
 166                 }
 167         }
 168
 169         pr_debug("Transitioning from P%d to P%d\n",
 170                 data->acpi_data.state, state);
 171
 172         /* cpufreq frequency struct */
 173         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
 174         cpufreq_freqs.new = data->freq_table[state].frequency;
 175
 176         /* notify cpufreq */
 177         cpufreq_notify_transition(policy, &cpufreq_freqs, CPUFREQ_PRECHANGE);
 178
 179         /*
 180          * First we write the target state's 'control' value to the
 181          * control_register.
 182          */
 183
 184         value = (u32) data->acpi_data.states[state].control;
 185
 186         pr_debug("Transitioning to state: 0x%08x\n", value);
 187
 188         ret = processor_set_pstate(value);
 189         if (ret) {
 190                 unsigned int tmp = cpufreq_freqs.new;
 191                 cpufreq_notify_transition(policy, &cpufreq_freqs,
 192                                 CPUFREQ_POSTCHANGE);
 193                 cpufreq_freqs.new = cpufreq_freqs.old;
 194                 cpufreq_freqs.old = tmp;
 195                 cpufreq_notify_transition(policy, &cpufreq_freqs,
 196                                 CPUFREQ_PRECHANGE);
 197                 cpufreq_notify_transition(policy, &cpufreq_freqs,
 198                                 CPUFREQ_POSTCHANGE);
 199                 printk(KERN_WARNING "Transition failed with error %d\n", ret);
 200                 retval = -ENODEV;
 201                 goto migrate_end;
 202         }
 203
 204         cpufreq_notify_transition(policy, &cpufreq_freqs, CPUFREQ_POSTCHANGE);
 205
 206         data->acpi_data.state = state;
 207
 208         retval = 0;
 209
 210 migrate_end:
 211         set_cpus_allowed_ptr(current, &saved_mask);
 212         return (retval);
 213 }
 214
 215
 216 static unsigned int
 217 acpi_cpufreq_get (
 218         unsigned int            cpu)
 219 {
 220         struct cpufreq_acpi_io *data = acpi_io_data[cpu];
 221
 222         pr_debug("acpi_cpufreq_get\n");
 223
 224         return processor_get_freq(data, cpu);
 225 }
 226
 227
 228 static int
 229 acpi_cpufreq_target (
 230         struct cpufreq_policy   *policy,
 231         unsigned int target_freq,
 232         unsigned int relation)
 233 {
 234         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 235         unsigned int next_state = 0;
 236         unsigned int result = 0;
 237
 238         pr_debug("acpi_cpufreq_setpolicy\n");
 239
 240         result = cpufreq_frequency_table_target(policy,
 241                         data->freq_table, target_freq, relation, &next_state);
 242         if (result)
 243                 return (result);
 244
 245         result = processor_set_freq(data, policy, next_state);
 246
 247         return (result);
 248 }
 249
 250
 251 static int
 252 acpi_cpufreq_verify (
 253         struct cpufreq_policy   *policy)
 254 {
 255         unsigned int result = 0;
 256         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 257
 258         pr_debug("acpi_cpufreq_verify\n");
 259
 260         result = cpufreq_frequency_table_verify(policy,
 261                         data->freq_table);
 262
 263         return (result);
 264 }
 265
 266
 267 static int
 268 acpi_cpufreq_cpu_init (
 269         struct cpufreq_policy   *policy)
 270 {
 271         unsigned int            i;
 272         unsigned int            cpu = policy->cpu;
 273         struct cpufreq_acpi_io  *data;
 274         unsigned int            result = 0;
 275
 276         pr_debug("acpi_cpufreq_cpu_init\n");
 277
 278         data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 279         if (!data)
 280                 return (-ENOMEM);
 281
 282         acpi_io_data[cpu] = data;
 283
 284         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 285
 286         if (result)
 287                 goto err_free;
 288
 289         /* capability check */
 290         if (data->acpi_data.state_count <= 1) {
 291                 pr_debug("No P-States\n");
 292                 result = -ENODEV;
 293                 goto err_unreg;
 294         }
 295
 296         if ((data->acpi_data.control_register.space_id !=
 297                                         ACPI_ADR_SPACE_FIXED_HARDWARE) ||
 298             (data->acpi_data.status_register.space_id !=
 299                                         ACPI_ADR_SPACE_FIXED_HARDWARE)) {
 300                 pr_debug("Unsupported address space [%d, %d]\n",
 301                         (u32) (data->acpi_data.control_register.space_id),
 302                         (u32) (data->acpi_data.status_register.space_id));
 303                 result = -ENODEV;
 304                 goto err_unreg;
 305         }
 306
 307         /* alloc freq_table */
 308         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
 309                                    (data->acpi_data.state_count + 1),
 310                                    GFP_KERNEL);
 311         if (!data->freq_table) {
 312                 result = -ENOMEM;
 313                 goto err_unreg;
 314         }
 315
 316         /* detect transition latency */
 317         policy->cpuinfo.transition_latency = 0;
 318         for (i=0; i<data->acpi_data.state_count; i++) {
 319                 if ((data->acpi_data.states[i].transition_latency * 1000) >
 320                     policy->cpuinfo.transition_latency) {
 321                         policy->cpuinfo.transition_latency =
 322                             data->acpi_data.states[i].transition_latency * 1000;
 323                 }
 324         }
 325         policy->cur = processor_get_freq(data, policy->cpu);
 326
 327         /* table init */
 328         for (i = 0; i <= data->acpi_data.state_count; i++)
 329         {
 330                 data->freq_table[i].index = i;
 331                 if (i < data->acpi_data.state_count) {
 332                         data->freq_table[i].frequency =
 333                               data->acpi_data.states[i].core_frequency * 1000;
 334                 } else {
 335                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 336                 }
 337         }
 338
 339         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 340         if (result) {
 341                 goto err_freqfree;
 342         }
 343
 344         /* notify BIOS that we exist */
 345         acpi_processor_notify_smm(THIS_MODULE);
 346
 347         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
 348                "activated.\n", cpu);
 349
 350         for (i = 0; i < data->acpi_data.state_count; i++)
 351                 pr_debug("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
 352                         (i == data->acpi_data.state?'*':' '), i,
 353                         (u32) data->acpi_data.states[i].core_frequency,
 354                         (u32) data->acpi_data.states[i].power,
 355                         (u32) data->acpi_data.states[i].transition_latency,
 356                         (u32) data->acpi_data.states[i].bus_master_latency,
 357                         (u32) data->acpi_data.states[i].status,
 358                         (u32) data->acpi_data.states[i].control);
 359
 360         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 361
 362         /* the first call to ->target() should result in us actually
 363          * writing something to the appropriate registers. */
 364         data->resume = 1;
 365
 366         return (result);
 367
 368  err_freqfree:
 369         kfree(data->freq_table);
 370  err_unreg:
 371         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 372  err_free:
 373         kfree(data);
 374         acpi_io_data[cpu] = NULL;
 375
 376         return (result);
 377 }
 378
 379
 380 static int
 381 acpi_cpufreq_cpu_exit (
 382         struct cpufreq_policy   *policy)
 383 {
 384         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 385
 386         pr_debug("acpi_cpufreq_cpu_exit\n");
 387
 388         if (data) {
 389                 cpufreq_frequency_table_put_attr(policy->cpu);
 390                 acpi_io_data[policy->cpu] = NULL;
 391                 acpi_processor_unregister_performance(&data->acpi_data,
 392                                                       policy->cpu);
 393                 kfree(data);
 394         }
 395
 396         return (0);
 397 }
 398
 399
 400 static struct freq_attr* acpi_cpufreq_attr[] = {
 401         &cpufreq_freq_attr_scaling_available_freqs,
 402         NULL,
 403 };
 404
 405
 406 static struct cpufreq_driver acpi_cpufreq_driver = {
 407         .verify         = acpi_cpufreq_verify,
 408         .target         = acpi_cpufreq_target,
 409         .get            = acpi_cpufreq_get,
 410         .init           = acpi_cpufreq_cpu_init,
 411         .exit           = acpi_cpufreq_cpu_exit,
 412         .name           = "acpi-cpufreq",
 413         .owner          = THIS_MODULE,
 414         .attr           = acpi_cpufreq_attr,
 415 };
 416
 417
 418 static int __init
 419 acpi_cpufreq_init (void)
 420 {
 421         pr_debug("acpi_cpufreq_init\n");
 422
 423         return cpufreq_register_driver(&acpi_cpufreq_driver);
 424 }
 425
 426
 427 static void __exit
 428 acpi_cpufreq_exit (void)
 429 {
 430         pr_debug("acpi_cpufreq_exit\n");
 431
 432         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 433         return;
 434 }
 435
 436
 437 late_initcall(acpi_cpufreq_init);
 438 module_exit(acpi_cpufreq_exit);
 439