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