kernel/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         cpumask_t               saved_mask;
 145         int                     retval;
 146
 147         pr_debug("processor_set_freq\n");
 148
 149         saved_mask = current->cpus_allowed;
 150         set_cpus_allowed_ptr(current, cpumask_of(policy->cpu));
 151         if (smp_processor_id() != policy->cpu) {
 152                 retval = -EAGAIN;
 153                 goto migrate_end;
 154         }
 155
 156         if (state == data->acpi_data.state) {
 157                 if (unlikely(data->resume)) {
 158                         pr_debug("Called after resume, resetting to P%d\n", state);
 159                         data->resume = 0;
 160                 } else {
 161                         pr_debug("Already at target state (P%d)\n", state);
 162                         retval = 0;
 163                         goto migrate_end;
 164                 }
 165         }
 166
 167         pr_debug("Transitioning from P%d to P%d\n",
 168                 data->acpi_data.state, state);
 169
 170         /*
 171          * First we write the target state's 'control' value to the
 172          * control_register.
 173          */
 174
 175         value = (u32) data->acpi_data.states[state].control;
 176
 177         pr_debug("Transitioning to state: 0x%08x\n", value);
 178
 179         ret = processor_set_pstate(value);
 180         if (ret) {
 181                 printk(KERN_WARNING "Transition failed with error %d\n", ret);
 182                 retval = -ENODEV;
 183                 goto migrate_end;
 184         }
 185
 186         data->acpi_data.state = state;
 187
 188         retval = 0;
 189
 190 migrate_end:
 191         set_cpus_allowed_ptr(current, &saved_mask);
 192         return (retval);
 193 }
 194
 195
 196 static unsigned int
 197 acpi_cpufreq_get (
 198         unsigned int            cpu)
 199 {
 200         struct cpufreq_acpi_io *data = acpi_io_data[cpu];
 201
 202         pr_debug("acpi_cpufreq_get\n");
 203
 204         return processor_get_freq(data, cpu);
 205 }
 206
 207
 208 static int
 209 acpi_cpufreq_target (
 210         struct cpufreq_policy   *policy,
 211         unsigned int index)
 212 {
 213         return processor_set_freq(acpi_io_data[policy->cpu], policy, index);
 214 }
 215
 216 static int
 217 acpi_cpufreq_cpu_init (
 218         struct cpufreq_policy   *policy)
 219 {
 220         unsigned int            i;
 221         unsigned int            cpu = policy->cpu;
 222         struct cpufreq_acpi_io  *data;
 223         unsigned int            result = 0;
 224
 225         pr_debug("acpi_cpufreq_cpu_init\n");
 226
 227         data = kzalloc(sizeof(*data), GFP_KERNEL);
 228         if (!data)
 229                 return (-ENOMEM);
 230
 231         acpi_io_data[cpu] = data;
 232
 233         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 234
 235         if (result)
 236                 goto err_free;
 237
 238         /* capability check */
 239         if (data->acpi_data.state_count <= 1) {
 240                 pr_debug("No P-States\n");
 241                 result = -ENODEV;
 242                 goto err_unreg;
 243         }
 244
 245         if ((data->acpi_data.control_register.space_id !=
 246                                         ACPI_ADR_SPACE_FIXED_HARDWARE) ||
 247             (data->acpi_data.status_register.space_id !=
 248                                         ACPI_ADR_SPACE_FIXED_HARDWARE)) {
 249                 pr_debug("Unsupported address space [%d, %d]\n",
 250                         (u32) (data->acpi_data.control_register.space_id),
 251                         (u32) (data->acpi_data.status_register.space_id));
 252                 result = -ENODEV;
 253                 goto err_unreg;
 254         }
 255
 256         /* alloc freq_table */
 257         data->freq_table = kzalloc(sizeof(*data->freq_table) *
 258                                    (data->acpi_data.state_count + 1),
 259                                    GFP_KERNEL);
 260         if (!data->freq_table) {
 261                 result = -ENOMEM;
 262                 goto err_unreg;
 263         }
 264
 265         /* detect transition latency */
 266         policy->cpuinfo.transition_latency = 0;
 267         for (i=0; i<data->acpi_data.state_count; i++) {
 268                 if ((data->acpi_data.states[i].transition_latency * 1000) >
 269                     policy->cpuinfo.transition_latency) {
 270                         policy->cpuinfo.transition_latency =
 271                             data->acpi_data.states[i].transition_latency * 1000;
 272                 }
 273         }
 274
 275         /* table init */
 276         for (i = 0; i <= data->acpi_data.state_count; i++)
 277         {
 278                 if (i < data->acpi_data.state_count) {
 279                         data->freq_table[i].frequency =
 280                               data->acpi_data.states[i].core_frequency * 1000;
 281                 } else {
 282                         data->freq_table[i].frequency = CPUFREQ_TABLE_END;
 283                 }
 284         }
 285
 286         result = cpufreq_table_validate_and_show(policy, data->freq_table);
 287         if (result) {
 288                 goto err_freqfree;
 289         }
 290
 291         /* notify BIOS that we exist */
 292         acpi_processor_notify_smm(THIS_MODULE);
 293
 294         printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
 295                "activated.\n", cpu);
 296
 297         for (i = 0; i < data->acpi_data.state_count; i++)
 298                 pr_debug("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
 299                         (i == data->acpi_data.state?'*':' '), i,
 300                         (u32) data->acpi_data.states[i].core_frequency,
 301                         (u32) data->acpi_data.states[i].power,
 302                         (u32) data->acpi_data.states[i].transition_latency,
 303                         (u32) data->acpi_data.states[i].bus_master_latency,
 304                         (u32) data->acpi_data.states[i].status,
 305                         (u32) data->acpi_data.states[i].control);
 306
 307         /* the first call to ->target() should result in us actually
 308          * writing something to the appropriate registers. */
 309         data->resume = 1;
 310
 311         return (result);
 312
 313  err_freqfree:
 314         kfree(data->freq_table);
 315  err_unreg:
 316         acpi_processor_unregister_performance(&data->acpi_data, cpu);
 317  err_free:
 318         kfree(data);
 319         acpi_io_data[cpu] = NULL;
 320
 321         return (result);
 322 }
 323
 324
 325 static int
 326 acpi_cpufreq_cpu_exit (
 327         struct cpufreq_policy   *policy)
 328 {
 329         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 330
 331         pr_debug("acpi_cpufreq_cpu_exit\n");
 332
 333         if (data) {
 334                 acpi_io_data[policy->cpu] = NULL;
 335                 acpi_processor_unregister_performance(&data->acpi_data,
 336                                                       policy->cpu);
 337                 kfree(data);
 338         }
 339
 340         return (0);
 341 }
 342
 343
 344 static struct cpufreq_driver acpi_cpufreq_driver = {
 345         .verify         = cpufreq_generic_frequency_table_verify,
 346         .target_index   = acpi_cpufreq_target,
 347         .get            = acpi_cpufreq_get,
 348         .init           = acpi_cpufreq_cpu_init,
 349         .exit           = acpi_cpufreq_cpu_exit,
 350         .name           = "acpi-cpufreq",
 351         .attr           = cpufreq_generic_attr,
 352 };
 353
 354
 355 static int __init
 356 acpi_cpufreq_init (void)
 357 {
 358         pr_debug("acpi_cpufreq_init\n");
 359
 360         return cpufreq_register_driver(&acpi_cpufreq_driver);
 361 }
 362
 363
 364 static void __exit
 365 acpi_cpufreq_exit (void)
 366 {
 367         pr_debug("acpi_cpufreq_exit\n");
 368
 369         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 370         return;
 371 }
 372
 373
 374 late_initcall(acpi_cpufreq_init);
 375 module_exit(acpi_cpufreq_exit);
 376