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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/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/cpufreq.h>
  16 #include <linux/proc_fs.h>
  17 #include <linux/seq_file.h>
  18 #include <asm/io.h>
  19 #include <asm/uaccess.h>
  20 #include <asm/pal.h>
  21
  22 #include <linux/acpi.h>
  23 #include <acpi/processor.h>
  24
  25 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
  26
  27 MODULE_AUTHOR("Venkatesh Pallipadi");
  28 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  29 MODULE_LICENSE("GPL");
  30
  31
  32 struct cpufreq_acpi_io {
  33         struct acpi_processor_performance       acpi_data;
  34         struct cpufreq_frequency_table          *freq_table;
  35         unsigned int                            resume;
  36 };
  37
  38 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
  39
  40 static struct cpufreq_driver acpi_cpufreq_driver;
  41
  42
  43 static int
  44 processor_set_pstate (
  45         u32     value)
  46 {
  47         s64 retval;
  48
  49         dprintk("processor_set_pstate\n");
  50
  51         retval = ia64_pal_set_pstate((u64)value);
  52
  53         if (retval) {
  54                 dprintk("Failed to set freq to 0x%x, with error 0x%x\n",
  55                         value, retval);
  56                 return -ENODEV;
  57         }
  58         return (int)retval;
  59 }
  60
  61
  62 static int
  63 processor_get_pstate (
  64         u32     *value)
  65 {
  66         u64     pstate_index = 0;
  67         s64     retval;
  68
  69         dprintk("processor_get_pstate\n");
  70
  71         retval = ia64_pal_get_pstate(&pstate_index,
  72                                      PAL_GET_PSTATE_TYPE_INSTANT);
  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].status)
  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         /* processor_get_pstate gets the instantaneous frequency */
 122         ret = processor_get_pstate(&value);
 123
 124         if (ret) {
 125                 set_cpus_allowed(current, saved_mask);
 126                 printk(KERN_WARNING "get performance failed with error %d\n",
 127                        ret);
 128                 ret = -EAGAIN;
 129                 goto migrate_end;
 130         }
 131         clock_freq = extract_clock(data, value, cpu);
 132         ret = (clock_freq*1000);
 133
 134 migrate_end:
 135         set_cpus_allowed(current, saved_mask);
 136         return ret;
 137 }
 138
 139
 140 static int
 141 processor_set_freq (
 142         struct cpufreq_acpi_io  *data,
 143         unsigned int            cpu,
 144         int                     state)
 145 {
 146         int                     ret = 0;
 147         u32                     value = 0;
 148         struct cpufreq_freqs    cpufreq_freqs;
 149         cpumask_t               saved_mask;
 150         int                     retval;
 151
 152         dprintk("processor_set_freq\n");
 153
 154         saved_mask = current->cpus_allowed;
 155         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 156         if (smp_processor_id() != cpu) {
 157                 retval = -EAGAIN;
 158                 goto migrate_end;
 159         }
 160
 161         if (state == data->acpi_data.state) {
 162                 if (unlikely(data->resume)) {
 163                         dprintk("Called after resume, resetting to P%d\n", state);
 164                         data->resume = 0;
 165                 } else {
 166                         dprintk("Already at target state (P%d)\n", state);
 167                         retval = 0;
 168                         goto migrate_end;
 169                 }
 170         }
 171
 172         dprintk("Transitioning from P%d to P%d\n",
 173                 data->acpi_data.state, state);
 174
 175         /* cpufreq frequency struct */
 176         cpufreq_freqs.cpu = cpu;
 177         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
 178         cpufreq_freqs.new = data->freq_table[state].frequency;
 179
 180         /* notify cpufreq */
 181         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 182
 183         /*
 184          * First we write the target state's 'control' value to the
 185          * control_register.
 186          */
 187
 188         value = (u32) data->acpi_data.states[state].control;
 189
 190         dprintk("Transitioning to state: 0x%08x\n", value);
 191
 192         ret = processor_set_pstate(value);
 193         if (ret) {
 194                 unsigned int tmp = cpufreq_freqs.new;
 195                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 196                 cpufreq_freqs.new = cpufreq_freqs.old;
 197                 cpufreq_freqs.old = tmp;
 198                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
 199                 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 200                 printk(KERN_WARNING "Transition failed with error %d\n", ret);
 201                 retval = -ENODEV;
 202                 goto migrate_end;
 203         }
 204
 205         cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
 206
 207         data->acpi_data.state = state;
 208
 209         retval = 0;
 210
 211 migrate_end:
 212         set_cpus_allowed(current, saved_mask);
 213         return (retval);
 214 }
 215
 216
 217 static unsigned int
 218 acpi_cpufreq_get (
 219         unsigned int            cpu)
 220 {
 221         struct cpufreq_acpi_io *data = acpi_io_data[cpu];
 222
 223         dprintk("acpi_cpufreq_get\n");
 224
 225         return processor_get_freq(data, cpu);
 226 }
 227
 228
 229 static int
 230 acpi_cpufreq_target (
 231         struct cpufreq_policy   *policy,
 232         unsigned int target_freq,
 233         unsigned int relation)
 234 {
 235         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 236         unsigned int next_state = 0;
 237         unsigned int result = 0;
 238
 239         dprintk("acpi_cpufreq_setpolicy\n");
 240
 241         result = cpufreq_frequency_table_target(policy,
 242                         data->freq_table, target_freq, relation, &next_state);
 243         if (result)
 244                 return (result);
 245
 246         result = processor_set_freq(data, policy->cpu, next_state);
 247
 248         return (result);
 249 }
 250
 251
 252 static int
 253 acpi_cpufreq_verify (
 254         struct cpufreq_policy   *policy)
 255 {
 256         unsigned int result = 0;
 257         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 258
 259         dprintk("acpi_cpufreq_verify\n");
 260
 261         result = cpufreq_frequency_table_verify(policy,
 262                         data->freq_table);
 263
 264         return (result);
 265 }
 266
 267
 268 static int
 269 acpi_cpufreq_cpu_init (
 270         struct cpufreq_policy   *policy)
 271 {
 272         unsigned int            i;
 273         unsigned int            cpu = policy->cpu;
 274         struct cpufreq_acpi_io  *data;
 275         unsigned int            result = 0;
 276
 277         dprintk("acpi_cpufreq_cpu_init\n");
 278
 279         data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
 280         if (!data)
 281                 return (-ENOMEM);
 282
 283         acpi_io_data[cpu] = data;
 284
 285         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 286
 287         if (result)
 288                 goto err_free;
 289
 290         /* capability check */
 291         if (data->acpi_data.state_count <= 1) {
 292                 dprintk("No P-States\n");
 293                 result = -ENODEV;
 294                 goto err_unreg;
 295         }
 296
 297         if ((data->acpi_data.control_register.space_id !=
 298                                         ACPI_ADR_SPACE_FIXED_HARDWARE) ||
 299             (data->acpi_data.status_register.space_id !=
 300                                         ACPI_ADR_SPACE_FIXED_HARDWARE)) {
 301                 dprintk("Unsupported address space [%d, %d]\n",
 302                         (u32) (data->acpi_data.control_register.space_id),
 303                         (u32) (data->acpi_data.status_register.space_id));
 304                 result = -ENODEV;
 305                 goto err_unreg;
 306         }
 307
 308         /* alloc freq_table */
 309         data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
 310                                    (data->acpi_data.state_count + 1),
 311                                    GFP_KERNEL);
 312         if (!data->freq_table) {
 313                 result = -ENOMEM;
 314                 goto err_unreg;
 315         }
 316
 317         /* detect transition latency */
 318         policy->cpuinfo.transition_latency = 0;
 319         for (i=0; i<data->acpi_data.state_count; i++) {
 320                 if ((data->acpi_data.states[i].transition_latency * 1000) >
 321                     policy->cpuinfo.transition_latency) {
 322                         policy->cpuinfo.transition_latency =
 323                             data->acpi_data.states[i].transition_latency * 1000;
 324                 }
 325         }
 326         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 327
 328         policy->cur = processor_get_freq(data, policy->cpu);
 329
 330         /* table init */
 331         for (i = 0; i <= data->acpi_data.state_count; i++)
 332         {
 333                 data->freq_table[i].index = i;
 334                 if (i < data->acpi_data.state_count) {
 335                         data->freq_table[i].frequency =
 336                               data->acpi_data.states[i].core_frequency * 1000;
 337                 } else {
 338                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 339                 }
 340         }
 341
 342         result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
 343         if (result) {
 344                 goto err_freqfree;
 345         }
 346
 347         /* notify BIOS that we exist */
 348         acpi_processor_notify_smm(THIS_MODULE);
 349
 350         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
 351                "activated.\n", cpu);
 352
 353         for (i = 0; i < data->acpi_data.state_count; i++)
 354                 dprintk("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
 355                         (i == data->acpi_data.state?'*':' '), i,
 356                         (u32) data->acpi_data.states[i].core_frequency,
 357                         (u32) data->acpi_data.states[i].power,
 358                         (u32) data->acpi_data.states[i].transition_latency,
 359                         (u32) data->acpi_data.states[i].bus_master_latency,
 360                         (u32) data->acpi_data.states[i].status,
 361                         (u32) data->acpi_data.states[i].control);
 362
 363         cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
 364
 365         /* the first call to ->target() should result in us actually
 366          * writing something to the appropriate registers. */
 367         data->resume = 1;
 368
 369         return (result);
 370
 371  err_freqfree:
 372         kfree(data->freq_table);
 373  err_unreg:
 374         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 375  err_free:
 376         kfree(data);
 377         acpi_io_data[cpu] = NULL;
 378
 379         return (result);
 380 }
 381
 382
 383 static int
 384 acpi_cpufreq_cpu_exit (
 385         struct cpufreq_policy   *policy)
 386 {
 387         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 388
 389         dprintk("acpi_cpufreq_cpu_exit\n");
 390
 391         if (data) {
 392                 cpufreq_frequency_table_put_attr(policy->cpu);
 393                 acpi_io_data[policy->cpu] = NULL;
 394                 acpi_processor_unregister_performance(&data->acpi_data,
 395                                                       policy->cpu);
 396                 kfree(data);
 397         }
 398
 399         return (0);
 400 }
 401
 402
 403 static struct freq_attr* acpi_cpufreq_attr[] = {
 404         &cpufreq_freq_attr_scaling_available_freqs,
 405         NULL,
 406 };
 407
 408
 409 static struct cpufreq_driver acpi_cpufreq_driver = {
 410         .verify         = acpi_cpufreq_verify,
 411         .target         = acpi_cpufreq_target,
 412         .get            = acpi_cpufreq_get,
 413         .init           = acpi_cpufreq_cpu_init,
 414         .exit           = acpi_cpufreq_cpu_exit,
 415         .name           = "acpi-cpufreq",
 416         .owner          = THIS_MODULE,
 417         .attr           = acpi_cpufreq_attr,
 418 };
 419
 420
 421 static int __init
 422 acpi_cpufreq_init (void)
 423 {
 424         dprintk("acpi_cpufreq_init\n");
 425
 426         return cpufreq_register_driver(&acpi_cpufreq_driver);
 427 }
 428
 429
 430 static void __exit
 431 acpi_cpufreq_exit (void)
 432 {
 433         dprintk("acpi_cpufreq_exit\n");
 434
 435         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 436         return;
 437 }
 438
 439
 440 late_initcall(acpi_cpufreq_init);
 441 module_exit(acpi_cpufreq_exit);
 442