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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/cpufreq.h>
  18 #include <linux/proc_fs.h>
  19 #include <linux/seq_file.h>
  20 #include <asm/io.h>
  21 #include <asm/uaccess.h>
  22 #include <asm/pal.h>
  23
  24 #include <linux/acpi.h>
  25 #include <acpi/processor.h>
  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         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                 pr_warn("get performance failed with error %d\n", 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                 pr_warn("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         struct cpufreq_frequency_table *freq_table;
 225
 226         pr_debug("acpi_cpufreq_cpu_init\n");
 227
 228         data = kzalloc(sizeof(*data), GFP_KERNEL);
 229         if (!data)
 230                 return (-ENOMEM);
 231
 232         acpi_io_data[cpu] = data;
 233
 234         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 235
 236         if (result)
 237                 goto err_free;
 238
 239         /* capability check */
 240         if (data->acpi_data.state_count <= 1) {
 241                 pr_debug("No P-States\n");
 242                 result = -ENODEV;
 243                 goto err_unreg;
 244         }
 245
 246         if ((data->acpi_data.control_register.space_id !=
 247                                         ACPI_ADR_SPACE_FIXED_HARDWARE) ||
 248             (data->acpi_data.status_register.space_id !=
 249                                         ACPI_ADR_SPACE_FIXED_HARDWARE)) {
 250                 pr_debug("Unsupported address space [%d, %d]\n",
 251                         (u32) (data->acpi_data.control_register.space_id),
 252                         (u32) (data->acpi_data.status_register.space_id));
 253                 result = -ENODEV;
 254                 goto err_unreg;
 255         }
 256
 257         /* alloc freq_table */
 258         freq_table = kzalloc(sizeof(*freq_table) *
 259                                    (data->acpi_data.state_count + 1),
 260                                    GFP_KERNEL);
 261         if (!freq_table) {
 262                 result = -ENOMEM;
 263                 goto err_unreg;
 264         }
 265
 266         /* detect transition latency */
 267         policy->cpuinfo.transition_latency = 0;
 268         for (i=0; i<data->acpi_data.state_count; i++) {
 269                 if ((data->acpi_data.states[i].transition_latency * 1000) >
 270                     policy->cpuinfo.transition_latency) {
 271                         policy->cpuinfo.transition_latency =
 272                             data->acpi_data.states[i].transition_latency * 1000;
 273                 }
 274         }
 275
 276         /* table init */
 277         for (i = 0; i <= data->acpi_data.state_count; i++)
 278         {
 279                 if (i < data->acpi_data.state_count) {
 280                         freq_table[i].frequency =
 281                               data->acpi_data.states[i].core_frequency * 1000;
 282                 } else {
 283                         freq_table[i].frequency = CPUFREQ_TABLE_END;
 284                 }
 285         }
 286
 287         result = cpufreq_table_validate_and_show(policy, freq_table);
 288         if (result) {
 289                 goto err_freqfree;
 290         }
 291
 292         /* notify BIOS that we exist */
 293         acpi_processor_notify_smm(THIS_MODULE);
 294
 295         pr_info("CPU%u - ACPI performance management 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(freq_table);
 315  err_unreg:
 316         acpi_processor_unregister_performance(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(policy->cpu);
 336                 kfree(policy->freq_table);
 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