drivers/cpufreq/ia64-acpi-cpufreq.c

   1 /*
   2  * This file provides the ACPI based P-state support. This
   3  * module works with generic cpufreq infrastructure. Most of
   4  * the code is based on i386 version
   5  * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
   6  *
   7  * Copyright (C) 2005 Intel Corp
   8  *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/slab.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 MODULE_AUTHOR("Venkatesh Pallipadi");
  26 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  27 MODULE_LICENSE("GPL");
  28
  29
  30 struct cpufreq_acpi_io {
  31         struct acpi_processor_performance       acpi_data;
  32         struct cpufreq_frequency_table          *freq_table;
  33         unsigned int                            resume;
  34 };
  35
  36 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
  37
  38 static struct cpufreq_driver acpi_cpufreq_driver;
  39
  40
  41 static int
  42 processor_set_pstate (
  43         u32     value)
  44 {
  45         s64 retval;
  46
  47         pr_debug("processor_set_pstate\n");
  48
  49         retval = ia64_pal_set_pstate((u64)value);
  50
  51         if (retval) {
  52                 pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n",
  53                         value, retval);
  54                 return -ENODEV;
  55         }
  56         return (int)retval;
  57 }
  58
  59
  60 static int
  61 processor_get_pstate (
  62         u32     *value)
  63 {
  64         u64     pstate_index = 0;
  65         s64     retval;
  66
  67         pr_debug("processor_get_pstate\n");
  68
  69         retval = ia64_pal_get_pstate(&pstate_index,
  70                                      PAL_GET_PSTATE_TYPE_INSTANT);
  71         *value = (u32) pstate_index;
  72
  73         if (retval)
  74                 pr_debug("Failed to get current freq with "
  75                         "error 0x%lx, idx 0x%x\n", retval, *value);
  76
  77         return (int)retval;
  78 }
  79
  80
  81 /* To be used only after data->acpi_data is initialized */
  82 static unsigned
  83 extract_clock (
  84         struct cpufreq_acpi_io *data,
  85         unsigned value,
  86         unsigned int cpu)
  87 {
  88         unsigned long i;
  89
  90         pr_debug("extract_clock\n");
  91
  92         for (i = 0; i < data->acpi_data.state_count; i++) {
  93                 if (value == data->acpi_data.states[i].status)
  94                         return data->acpi_data.states[i].core_frequency;
  95         }
  96         return data->acpi_data.states[i-1].core_frequency;
  97 }
  98
  99
 100 static unsigned int
 101 processor_get_freq (
 102         struct cpufreq_acpi_io  *data,
 103         unsigned int            cpu)
 104 {
 105         int                     ret = 0;
 106         u32                     value = 0;
 107         cpumask_t               saved_mask;
 108         unsigned long           clock_freq;
 109
 110         pr_debug("processor_get_freq\n");
 111
 112         saved_mask = current->cpus_allowed;
 113         set_cpus_allowed_ptr(current, cpumask_of(cpu));
 114         if (smp_processor_id() != cpu)
 115                 goto migrate_end;
 116
 117         /* processor_get_pstate gets the instantaneous frequency */
 118         ret = processor_get_pstate(&value);
 119
 120         if (ret) {
 121                 set_cpus_allowed_ptr(current, &saved_mask);
 122                 printk(KERN_WARNING "get performance failed with error %d\n",
 123                        ret);
 124                 ret = 0;
 125                 goto migrate_end;
 126         }
 127         clock_freq = extract_clock(data, value, cpu);
 128         ret = (clock_freq*1000);
 129
 130 migrate_end:
 131         set_cpus_allowed_ptr(current, &saved_mask);
 132         return ret;
 133 }
 134
 135
 136 static int
 137 processor_set_freq (
 138         struct cpufreq_acpi_io  *data,
 139         struct cpufreq_policy   *policy,
 140         int                     state)
 141 {
 142         int                     ret = 0;
 143         u32                     value = 0;
 144         struct cpufreq_freqs    cpufreq_freqs;
 145         cpumask_t               saved_mask;
 146         int                     retval;
 147
 148         pr_debug("processor_set_freq\n");
 149
 150         saved_mask = current->cpus_allowed;
 151         set_cpus_allowed_ptr(current, cpumask_of(policy->cpu));
 152         if (smp_processor_id() != policy->cpu) {
 153                 retval = -EAGAIN;
 154                 goto migrate_end;
 155         }
 156
 157         if (state == data->acpi_data.state) {
 158                 if (unlikely(data->resume)) {
 159                         pr_debug("Called after resume, resetting to P%d\n", state);
 160                         data->resume = 0;
 161                 } else {
 162                         pr_debug("Already at target state (P%d)\n", state);
 163                         retval = 0;
 164                         goto migrate_end;
 165                 }
 166         }
 167
 168         pr_debug("Transitioning from P%d to P%d\n",
 169                 data->acpi_data.state, state);
 170
 171         /* cpufreq frequency struct */
 172         cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
 173         cpufreq_freqs.new = data->freq_table[state].frequency;
 174
 175         /* notify cpufreq */
 176         cpufreq_notify_transition(policy, &cpufreq_freqs, CPUFREQ_PRECHANGE);
 177
 178         /*
 179          * First we write the target state's 'control' value to the
 180          * control_register.
 181          */
 182
 183         value = (u32) data->acpi_data.states[state].control;
 184
 185         pr_debug("Transitioning to state: 0x%08x\n", value);
 186
 187         ret = processor_set_pstate(value);
 188         if (ret) {
 189                 unsigned int tmp = cpufreq_freqs.new;
 190                 cpufreq_notify_transition(policy, &cpufreq_freqs,
 191                                 CPUFREQ_POSTCHANGE);
 192                 cpufreq_freqs.new = cpufreq_freqs.old;
 193                 cpufreq_freqs.old = tmp;
 194                 cpufreq_notify_transition(policy, &cpufreq_freqs,
 195                                 CPUFREQ_PRECHANGE);
 196                 cpufreq_notify_transition(policy, &cpufreq_freqs,
 197                                 CPUFREQ_POSTCHANGE);
 198                 printk(KERN_WARNING "Transition failed with error %d\n", ret);
 199                 retval = -ENODEV;
 200                 goto migrate_end;
 201         }
 202
 203         cpufreq_notify_transition(policy, &cpufreq_freqs, CPUFREQ_POSTCHANGE);
 204
 205         data->acpi_data.state = state;
 206
 207         retval = 0;
 208
 209 migrate_end:
 210         set_cpus_allowed_ptr(current, &saved_mask);
 211         return (retval);
 212 }
 213
 214
 215 static unsigned int
 216 acpi_cpufreq_get (
 217         unsigned int            cpu)
 218 {
 219         struct cpufreq_acpi_io *data = acpi_io_data[cpu];
 220
 221         pr_debug("acpi_cpufreq_get\n");
 222
 223         return processor_get_freq(data, cpu);
 224 }
 225
 226
 227 static int
 228 acpi_cpufreq_target (
 229         struct cpufreq_policy   *policy,
 230         unsigned int target_freq,
 231         unsigned int relation)
 232 {
 233         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 234         unsigned int next_state = 0;
 235         unsigned int result = 0;
 236
 237         pr_debug("acpi_cpufreq_setpolicy\n");
 238
 239         result = cpufreq_frequency_table_target(policy,
 240                         data->freq_table, target_freq, relation, &next_state);
 241         if (result)
 242                 return (result);
 243
 244         result = processor_set_freq(data, policy, next_state);
 245
 246         return (result);
 247 }
 248
 249
 250 static int
 251 acpi_cpufreq_cpu_init (
 252         struct cpufreq_policy   *policy)
 253 {
 254         unsigned int            i;
 255         unsigned int            cpu = policy->cpu;
 256         struct cpufreq_acpi_io  *data;
 257         unsigned int            result = 0;
 258
 259         pr_debug("acpi_cpufreq_cpu_init\n");
 260
 261         data = kzalloc(sizeof(*data), GFP_KERNEL);
 262         if (!data)
 263                 return (-ENOMEM);
 264
 265         acpi_io_data[cpu] = data;
 266
 267         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 268
 269         if (result)
 270                 goto err_free;
 271
 272         /* capability check */
 273         if (data->acpi_data.state_count <= 1) {
 274                 pr_debug("No P-States\n");
 275                 result = -ENODEV;
 276                 goto err_unreg;
 277         }
 278
 279         if ((data->acpi_data.control_register.space_id !=
 280                                         ACPI_ADR_SPACE_FIXED_HARDWARE) ||
 281             (data->acpi_data.status_register.space_id !=
 282                                         ACPI_ADR_SPACE_FIXED_HARDWARE)) {
 283                 pr_debug("Unsupported address space [%d, %d]\n",
 284                         (u32) (data->acpi_data.control_register.space_id),
 285                         (u32) (data->acpi_data.status_register.space_id));
 286                 result = -ENODEV;
 287                 goto err_unreg;
 288         }
 289
 290         /* alloc freq_table */
 291         data->freq_table = kmalloc(sizeof(*data->freq_table) *
 292                                    (data->acpi_data.state_count + 1),
 293                                    GFP_KERNEL);
 294         if (!data->freq_table) {
 295                 result = -ENOMEM;
 296                 goto err_unreg;
 297         }
 298
 299         /* detect transition latency */
 300         policy->cpuinfo.transition_latency = 0;
 301         for (i=0; i<data->acpi_data.state_count; i++) {
 302                 if ((data->acpi_data.states[i].transition_latency * 1000) >
 303                     policy->cpuinfo.transition_latency) {
 304                         policy->cpuinfo.transition_latency =
 305                             data->acpi_data.states[i].transition_latency * 1000;
 306                 }
 307         }
 308
 309         /* table init */
 310         for (i = 0; i <= data->acpi_data.state_count; i++)
 311         {
 312                 data->freq_table[i].driver_data = i;
 313                 if (i < data->acpi_data.state_count) {
 314                         data->freq_table[i].frequency =
 315                               data->acpi_data.states[i].core_frequency * 1000;
 316                 } else {
 317                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 318                 }
 319         }
 320
 321         result = cpufreq_table_validate_and_show(policy, data->freq_table);
 322         if (result) {
 323                 goto err_freqfree;
 324         }
 325
 326         /* notify BIOS that we exist */
 327         acpi_processor_notify_smm(THIS_MODULE);
 328
 329         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
 330                "activated.\n", cpu);
 331
 332         for (i = 0; i < data->acpi_data.state_count; i++)
 333                 pr_debug("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
 334                         (i == data->acpi_data.state?'*':' '), i,
 335                         (u32) data->acpi_data.states[i].core_frequency,
 336                         (u32) data->acpi_data.states[i].power,
 337                         (u32) data->acpi_data.states[i].transition_latency,
 338                         (u32) data->acpi_data.states[i].bus_master_latency,
 339                         (u32) data->acpi_data.states[i].status,
 340                         (u32) data->acpi_data.states[i].control);
 341
 342         /* the first call to ->target() should result in us actually
 343          * writing something to the appropriate registers. */
 344         data->resume = 1;
 345
 346         return (result);
 347
 348  err_freqfree:
 349         kfree(data->freq_table);
 350  err_unreg:
 351         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 352  err_free:
 353         kfree(data);
 354         acpi_io_data[cpu] = NULL;
 355
 356         return (result);
 357 }
 358
 359
 360 static int
 361 acpi_cpufreq_cpu_exit (
 362         struct cpufreq_policy   *policy)
 363 {
 364         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 365
 366         pr_debug("acpi_cpufreq_cpu_exit\n");
 367
 368         if (data) {
 369                 cpufreq_frequency_table_put_attr(policy->cpu);
 370                 acpi_io_data[policy->cpu] = NULL;
 371                 acpi_processor_unregister_performance(&data->acpi_data,
 372                                                       policy->cpu);
 373                 kfree(data);
 374         }
 375
 376         return (0);
 377 }
 378
 379
 380 static struct cpufreq_driver acpi_cpufreq_driver = {
 381         .verify         = cpufreq_generic_frequency_table_verify,
 382         .target         = acpi_cpufreq_target,
 383         .get            = acpi_cpufreq_get,
 384         .init           = acpi_cpufreq_cpu_init,
 385         .exit           = acpi_cpufreq_cpu_exit,
 386         .name           = "acpi-cpufreq",
 387         .attr           = cpufreq_generic_attr,
 388 };
 389
 390
 391 static int __init
 392 acpi_cpufreq_init (void)
 393 {
 394         pr_debug("acpi_cpufreq_init\n");
 395
 396         return cpufreq_register_driver(&acpi_cpufreq_driver);
 397 }
 398
 399
 400 static void __exit
 401 acpi_cpufreq_exit (void)
 402 {
 403         pr_debug("acpi_cpufreq_exit\n");
 404
 405         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 406         return;
 407 }
 408
 409
 410 late_initcall(acpi_cpufreq_init);
 411 module_exit(acpi_cpufreq_exit);
 412