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 <[email protected]>
   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 <asm/io.h>
  20 #include <linux/uaccess.h>
  21 #include <asm/pal.h>
  22
  23 #include <linux/acpi.h>
  24 #include <acpi/processor.h>
  25
  26 MODULE_AUTHOR("Venkatesh Pallipadi");
  27 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  28 MODULE_LICENSE("GPL");
  29
  30 struct cpufreq_acpi_io {
  31         struct acpi_processor_performance       acpi_data;
  32         unsigned int                            resume;
  33 };
  34
  35 struct cpufreq_acpi_req {
  36         unsigned int            cpu;
  37         unsigned int            state;
  38 };
  39
  40 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
  41
  42 static struct cpufreq_driver acpi_cpufreq_driver;
  43
  44
  45 static int
  46 processor_set_pstate (
  47         u32     value)
  48 {
  49         s64 retval;
  50
  51         pr_debug("processor_set_pstate\n");
  52
  53         retval = ia64_pal_set_pstate((u64)value);
  54
  55         if (retval) {
  56                 pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n",
  57                         value, retval);
  58                 return -ENODEV;
  59         }
  60         return (int)retval;
  61 }
  62
  63
  64 static int
  65 processor_get_pstate (
  66         u32     *value)
  67 {
  68         u64     pstate_index = 0;
  69         s64     retval;
  70
  71         pr_debug("processor_get_pstate\n");
  72
  73         retval = ia64_pal_get_pstate(&pstate_index,
  74                                      PAL_GET_PSTATE_TYPE_INSTANT);
  75         *value = (u32) pstate_index;
  76
  77         if (retval)
  78                 pr_debug("Failed to get current freq with "
  79                         "error 0x%lx, idx 0x%x\n", retval, *value);
  80
  81         return (int)retval;
  82 }
  83
  84
  85 /* To be used only after data->acpi_data is initialized */
  86 static unsigned
  87 extract_clock (
  88         struct cpufreq_acpi_io *data,
  89         unsigned value)
  90 {
  91         unsigned long i;
  92
  93         pr_debug("extract_clock\n");
  94
  95         for (i = 0; i < data->acpi_data.state_count; i++) {
  96                 if (value == data->acpi_data.states[i].status)
  97                         return data->acpi_data.states[i].core_frequency;
  98         }
  99         return data->acpi_data.states[i-1].core_frequency;
 100 }
 101
 102
 103 static long
 104 processor_get_freq (
 105         void *arg)
 106 {
 107         struct cpufreq_acpi_req *req = arg;
 108         unsigned int            cpu = req->cpu;
 109         struct cpufreq_acpi_io  *data = acpi_io_data[cpu];
 110         u32                     value;
 111         int                     ret;
 112
 113         pr_debug("processor_get_freq\n");
 114         if (smp_processor_id() != cpu)
 115                 return -EAGAIN;
 116
 117         /* processor_get_pstate gets the instantaneous frequency */
 118         ret = processor_get_pstate(&value);
 119         if (ret) {
 120                 pr_warn("get performance failed with error %d\n", ret);
 121                 return ret;
 122         }
 123         return 1000 * extract_clock(data, value);
 124 }
 125
 126
 127 static long
 128 processor_set_freq (
 129         void *arg)
 130 {
 131         struct cpufreq_acpi_req *req = arg;
 132         unsigned int            cpu = req->cpu;
 133         struct cpufreq_acpi_io  *data = acpi_io_data[cpu];
 134         int                     ret, state = req->state;
 135         u32                     value;
 136
 137         pr_debug("processor_set_freq\n");
 138         if (smp_processor_id() != cpu)
 139                 return -EAGAIN;
 140
 141         if (state == data->acpi_data.state) {
 142                 if (unlikely(data->resume)) {
 143                         pr_debug("Called after resume, resetting to P%d\n", state);
 144                         data->resume = 0;
 145                 } else {
 146                         pr_debug("Already at target state (P%d)\n", state);
 147                         return 0;
 148                 }
 149         }
 150
 151         pr_debug("Transitioning from P%d to P%d\n",
 152                 data->acpi_data.state, state);
 153
 154         /*
 155          * First we write the target state's 'control' value to the
 156          * control_register.
 157          */
 158         value = (u32) data->acpi_data.states[state].control;
 159
 160         pr_debug("Transitioning to state: 0x%08x\n", value);
 161
 162         ret = processor_set_pstate(value);
 163         if (ret) {
 164                 pr_warn("Transition failed with error %d\n", ret);
 165                 return -ENODEV;
 166         }
 167
 168         data->acpi_data.state = state;
 169         return 0;
 170 }
 171
 172
 173 static unsigned int
 174 acpi_cpufreq_get (
 175         unsigned int            cpu)
 176 {
 177         struct cpufreq_acpi_req req;
 178         long ret;
 179
 180         req.cpu = cpu;
 181         ret = work_on_cpu(cpu, processor_get_freq, &req);
 182
 183         return ret > 0 ? (unsigned int) ret : 0;
 184 }
 185
 186
 187 static int
 188 acpi_cpufreq_target (
 189         struct cpufreq_policy   *policy,
 190         unsigned int index)
 191 {
 192         struct cpufreq_acpi_req req;
 193
 194         req.cpu = policy->cpu;
 195         req.state = index;
 196
 197         return work_on_cpu(req.cpu, processor_set_freq, &req);
 198 }
 199
 200 static int
 201 acpi_cpufreq_cpu_init (
 202         struct cpufreq_policy   *policy)
 203 {
 204         unsigned int            i;
 205         unsigned int            cpu = policy->cpu;
 206         struct cpufreq_acpi_io  *data;
 207         unsigned int            result = 0;
 208         struct cpufreq_frequency_table *freq_table;
 209
 210         pr_debug("acpi_cpufreq_cpu_init\n");
 211
 212         data = kzalloc(sizeof(*data), GFP_KERNEL);
 213         if (!data)
 214                 return (-ENOMEM);
 215
 216         acpi_io_data[cpu] = data;
 217
 218         result = acpi_processor_register_performance(&data->acpi_data, cpu);
 219
 220         if (result)
 221                 goto err_free;
 222
 223         /* capability check */
 224         if (data->acpi_data.state_count <= 1) {
 225                 pr_debug("No P-States\n");
 226                 result = -ENODEV;
 227                 goto err_unreg;
 228         }
 229
 230         if ((data->acpi_data.control_register.space_id !=
 231                                         ACPI_ADR_SPACE_FIXED_HARDWARE) ||
 232             (data->acpi_data.status_register.space_id !=
 233                                         ACPI_ADR_SPACE_FIXED_HARDWARE)) {
 234                 pr_debug("Unsupported address space [%d, %d]\n",
 235                         (u32) (data->acpi_data.control_register.space_id),
 236                         (u32) (data->acpi_data.status_register.space_id));
 237                 result = -ENODEV;
 238                 goto err_unreg;
 239         }
 240
 241         /* alloc freq_table */
 242         freq_table = kcalloc(data->acpi_data.state_count + 1,
 243                                    sizeof(*freq_table),
 244                                    GFP_KERNEL);
 245         if (!freq_table) {
 246                 result = -ENOMEM;
 247                 goto err_unreg;
 248         }
 249
 250         /* detect transition latency */
 251         policy->cpuinfo.transition_latency = 0;
 252         for (i=0; i<data->acpi_data.state_count; i++) {
 253                 if ((data->acpi_data.states[i].transition_latency * 1000) >
 254                     policy->cpuinfo.transition_latency) {
 255                         policy->cpuinfo.transition_latency =
 256                             data->acpi_data.states[i].transition_latency * 1000;
 257                 }
 258         }
 259
 260         /* table init */
 261         for (i = 0; i <= data->acpi_data.state_count; i++)
 262         {
 263                 if (i < data->acpi_data.state_count) {
 264                         freq_table[i].frequency =
 265                               data->acpi_data.states[i].core_frequency * 1000;
 266                 } else {
 267                         freq_table[i].frequency = CPUFREQ_TABLE_END;
 268                 }
 269         }
 270
 271         policy->freq_table = freq_table;
 272
 273         /* notify BIOS that we exist */
 274         acpi_processor_notify_smm(THIS_MODULE);
 275
 276         pr_info("CPU%u - ACPI performance management activated\n", cpu);
 277
 278         for (i = 0; i < data->acpi_data.state_count; i++)
 279                 pr_debug("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
 280                         (i == data->acpi_data.state?'*':' '), i,
 281                         (u32) data->acpi_data.states[i].core_frequency,
 282                         (u32) data->acpi_data.states[i].power,
 283                         (u32) data->acpi_data.states[i].transition_latency,
 284                         (u32) data->acpi_data.states[i].bus_master_latency,
 285                         (u32) data->acpi_data.states[i].status,
 286                         (u32) data->acpi_data.states[i].control);
 287
 288         /* the first call to ->target() should result in us actually
 289          * writing something to the appropriate registers. */
 290         data->resume = 1;
 291
 292         return (result);
 293
 294  err_unreg:
 295         acpi_processor_unregister_performance(cpu);
 296  err_free:
 297         kfree(data);
 298         acpi_io_data[cpu] = NULL;
 299
 300         return (result);
 301 }
 302
 303
 304 static int
 305 acpi_cpufreq_cpu_exit (
 306         struct cpufreq_policy   *policy)
 307 {
 308         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
 309
 310         pr_debug("acpi_cpufreq_cpu_exit\n");
 311
 312         if (data) {
 313                 acpi_io_data[policy->cpu] = NULL;
 314                 acpi_processor_unregister_performance(policy->cpu);
 315                 kfree(policy->freq_table);
 316                 kfree(data);
 317         }
 318
 319         return (0);
 320 }
 321
 322
 323 static struct cpufreq_driver acpi_cpufreq_driver = {
 324         .verify         = cpufreq_generic_frequency_table_verify,
 325         .target_index   = acpi_cpufreq_target,
 326         .get            = acpi_cpufreq_get,
 327         .init           = acpi_cpufreq_cpu_init,
 328         .exit           = acpi_cpufreq_cpu_exit,
 329         .name           = "acpi-cpufreq",
 330         .attr           = cpufreq_generic_attr,
 331 };
 332
 333
 334 static int __init
 335 acpi_cpufreq_init (void)
 336 {
 337         pr_debug("acpi_cpufreq_init\n");
 338
 339         return cpufreq_register_driver(&acpi_cpufreq_driver);
 340 }
 341
 342
 343 static void __exit
 344 acpi_cpufreq_exit (void)
 345 {
 346         pr_debug("acpi_cpufreq_exit\n");
 347
 348         cpufreq_unregister_driver(&acpi_cpufreq_driver);
 349 }
 350
 351 late_initcall(acpi_cpufreq_init);
 352 module_exit(acpi_cpufreq_exit);