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