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         unsigned int            cpu,
 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(cpu));
 153         if (smp_processor_id() != 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.cpu = cpu;
 174         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
 175         cpufreq_freqs.new = data->freq_table[state].frequency;
 176
 177         /* notify cpufreq */
 178         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 179
 180         /*
 181          * First we write the target state's 'control' value to the
 182          * control_register.
 183          */
 184
 185         value = (u32) data->acpi_data.states[state].control;
 186
 187         pr_debug("Transitioning to state: 0x%08x\n", value);
 188
 189         ret = processor_set_pstate(value);
 190         if (ret) {
 191                 unsigned int tmp = cpufreq_freqs.new;
 192                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 193                 cpufreq_freqs.new = cpufreq_freqs.old;
 194                 cpufreq_freqs.old = tmp;
 195                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 196                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 197                 printk(KERN_WARNING "Transition failed with error %d\n", ret);
 198                 retval = -ENODEV;
 199                 goto migrate_end;
 200         }
 201
 202         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 203
 204         data->acpi_data.state = state;
 205
 206         retval = 0;
 207
 208 migrate_end:
 209         set_cpus_allowed_ptr(current, &saved_mask);
 210         return (retval);
 211 }
 212
 213
 214 static unsigned int
 215 acpi_cpufreq_get (
 216         unsigned int            cpu)
 217 {
 218         struct cpufreq_acpi_io *data = acpi_io_data[cpu];
 219
 220         pr_debug("acpi_cpufreq_get\n");
 221
 222         return processor_get_freq(data, cpu);
 223 }
 224
 225
 226 static int
 227 acpi_cpufreq_target (
 228         struct cpufreq_policy   *policy,
 229         unsigned int target_freq,
 230         unsigned int relation)
 231 {
 232         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 233         unsigned int next_state = 0;
 234         unsigned int result = 0;
 235
 236         pr_debug("acpi_cpufreq_setpolicy\n");
 237
 238         result = cpufreq_frequency_table_target(policy,
 239                         data->freq_table, target_freq, relation, &next_state);
 240         if (result)
 241                 return (result);
 242
 243         result = processor_set_freq(data, policy->cpu, next_state);
 244
 245         return (result);
 246 }
 247
 248
 249 static int
 250 acpi_cpufreq_verify (
 251         struct cpufreq_policy   *policy)
 252 {
 253         unsigned int result = 0;
 254         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 255
 256         pr_debug("acpi_cpufreq_verify\n");
 257
 258         result = cpufreq_frequency_table_verify(policy,
 259                         data->freq_table);
 260
 261         return (result);
 262 }
 263
 264
 265 static int
 266 acpi_cpufreq_cpu_init (
 267         struct cpufreq_policy   *policy)
 268 {
 269         unsigned int            i;
 270         unsigned int            cpu = policy->cpu;
 271         struct cpufreq_acpi_io  *data;
 272         unsigned int            result = 0;
 273
 274         pr_debug("acpi_cpufreq_cpu_init\n");
 275
 276         data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 277         if (!data)
 278                 return (-ENOMEM);
 279
 280         acpi_io_data[cpu] = data;
 281
 282         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 283
 284         if (result)
 285                 goto err_free;
 286
 287         /* capability check */
 288         if (data->acpi_data.state_count <= 1) {
 289                 pr_debug("No P-States\n");
 290                 result = -ENODEV;
 291                 goto err_unreg;
 292         }
 293
 294         if ((data->acpi_data.control_register.space_id !=
 295                                         ACPI_ADR_SPACE_FIXED_HARDWARE) ||
 296             (data->acpi_data.status_register.space_id !=
 297                                         ACPI_ADR_SPACE_FIXED_HARDWARE)) {
 298                 pr_debug("Unsupported address space [%d, %d]\n",
 299                         (u32) (data->acpi_data.control_register.space_id),
 300                         (u32) (data->acpi_data.status_register.space_id));
 301                 result = -ENODEV;
 302                 goto err_unreg;
 303         }
 304
 305         /* alloc freq_table */
 306         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
 307                                    (data->acpi_data.state_count + 1),
 308                                    GFP_KERNEL);
 309         if (!data->freq_table) {
 310                 result = -ENOMEM;
 311                 goto err_unreg;
 312         }
 313
 314         /* detect transition latency */
 315         policy->cpuinfo.transition_latency = 0;
 316         for (i=0; i<data->acpi_data.state_count; i++) {
 317                 if ((data->acpi_data.states[i].transition_latency * 1000) >
 318                     policy->cpuinfo.transition_latency) {
 319                         policy->cpuinfo.transition_latency =
 320                             data->acpi_data.states[i].transition_latency * 1000;
 321                 }
 322         }
 323         policy->cur = processor_get_freq(data, policy->cpu);
 324
 325         /* table init */
 326         for (i = 0; i <= data->acpi_data.state_count; i++)
 327         {
 328                 data->freq_table[i].index = i;
 329                 if (i < data->acpi_data.state_count) {
 330                         data->freq_table[i].frequency =
 331                               data->acpi_data.states[i].core_frequency * 1000;
 332                 } else {
 333                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 334                 }
 335         }
 336
 337         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 338         if (result) {
 339                 goto err_freqfree;
 340         }
 341
 342         /* notify BIOS that we exist */
 343         acpi_processor_notify_smm(THIS_MODULE);
 344
 345         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
 346                "activated.\n", cpu);
 347
 348         for (i = 0; i < data->acpi_data.state_count; i++)
 349                 pr_debug("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
 350                         (i == data->acpi_data.state?'*':' '), i,
 351                         (u32) data->acpi_data.states[i].core_frequency,
 352                         (u32) data->acpi_data.states[i].power,
 353                         (u32) data->acpi_data.states[i].transition_latency,
 354                         (u32) data->acpi_data.states[i].bus_master_latency,
 355                         (u32) data->acpi_data.states[i].status,
 356                         (u32) data->acpi_data.states[i].control);
 357
 358         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 359
 360         /* the first call to ->target() should result in us actually
 361          * writing something to the appropriate registers. */
 362         data->resume = 1;
 363
 364         return (result);
 365
 366  err_freqfree:
 367         kfree(data->freq_table);
 368  err_unreg:
 369         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 370  err_free:
 371         kfree(data);
 372         acpi_io_data[cpu] = NULL;
 373
 374         return (result);
 375 }
 376
 377
 378 static int
 379 acpi_cpufreq_cpu_exit (
 380         struct cpufreq_policy   *policy)
 381 {
 382         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 383
 384         pr_debug("acpi_cpufreq_cpu_exit\n");
 385
 386         if (data) {
 387                 cpufreq_frequency_table_put_attr(policy->cpu);
 388                 acpi_io_data[policy->cpu] = NULL;
 389                 acpi_processor_unregister_performance(&data->acpi_data,
 390                                                       policy->cpu);
 391                 kfree(data);
 392         }
 393
 394         return (0);
 395 }
 396
 397
 398 static struct freq_attr* acpi_cpufreq_attr[] = {
 399         &cpufreq_freq_attr_scaling_available_freqs,
 400         NULL,
 401 };
 402
 403
 404 static struct cpufreq_driver acpi_cpufreq_driver = {
 405         .verify         = acpi_cpufreq_verify,
 406         .target         = acpi_cpufreq_target,
 407         .get            = acpi_cpufreq_get,
 408         .init           = acpi_cpufreq_cpu_init,
 409         .exit           = acpi_cpufreq_cpu_exit,
 410         .name           = "acpi-cpufreq",
 411         .owner          = THIS_MODULE,
 412         .attr           = acpi_cpufreq_attr,
 413 };
 414
 415
 416 static int __init
 417 acpi_cpufreq_init (void)
 418 {
 419         pr_debug("acpi_cpufreq_init\n");
 420
 421         return cpufreq_register_driver(&acpi_cpufreq_driver);
 422 }
 423
 424
 425 static void __exit
 426 acpi_cpufreq_exit (void)
 427 {
 428         pr_debug("acpi_cpufreq_exit\n");
 429
 430         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 431         return;
 432 }
 433
 434
 435 late_initcall(acpi_cpufreq_init);
 436 module_exit(acpi_cpufreq_exit);
 437