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processor_throttling.c

/*
 * processor_throttling.c - Throttling submodule of the ACPI processor driver
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
 *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 *                - Added processor hotplug support
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

#include <asm/io.h>
#include <asm/uaccess.h>

#include <acpi/acpi_bus.h>
#include <acpi/processor.h>

#define ACPI_PROCESSOR_COMPONENT        0x01000000
#define ACPI_PROCESSOR_CLASS            "processor"
#define _COMPONENT              ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_throttling");

static int acpi_processor_get_throttling(struct acpi_processor *pr);
int acpi_processor_set_throttling(struct acpi_processor *pr, int state);

/*
 * _TPC - Throttling Present Capabilities
 */
static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
{
      acpi_status status = 0;
      unsigned long tpc = 0;

      if (!pr)
            return -EINVAL;
      status = acpi_evaluate_integer(pr->handle, "_TPC", NULL, &tpc);
      if (ACPI_FAILURE(status)) {
            if (status != AE_NOT_FOUND) {
                  ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TPC"));
            }
            return -ENODEV;
      }
      pr->throttling_platform_limit = (int)tpc;
      return 0;
}

int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
{
      int result = 0;
      int throttling_limit;
      int current_state;
      struct acpi_processor_limit *limit;
      int target_state;

      result = acpi_processor_get_platform_limit(pr);
      if (result) {
            /* Throttling Limit is unsupported */
            return result;
      }

      throttling_limit = pr->throttling_platform_limit;
      if (throttling_limit >= pr->throttling.state_count) {
            /* Uncorrect Throttling Limit */
            return -EINVAL;
      }

      current_state = pr->throttling.state;
      if (current_state > throttling_limit) {
            /*
             * The current state can meet the requirement of
             * _TPC limit. But it is reasonable that OSPM changes
             * t-states from high to low for better performance.
             * Of course the limit condition of thermal
             * and user should be considered.
             */
            limit = &pr->limit;
            target_state = throttling_limit;
            if (limit->thermal.tx > target_state)
                  target_state = limit->thermal.tx;
            if (limit->user.tx > target_state)
                  target_state = limit->user.tx;
      } else if (current_state == throttling_limit) {
            /*
             * Unnecessary to change the throttling state
             */
            return 0;
      } else {
            /*
             * If the current state is lower than the limit of _TPC, it
             * will be forced to switch to the throttling state defined
             * by throttling_platfor_limit.
             * Because the previous state meets with the limit condition
             * of thermal and user, it is unnecessary to check it again.
             */
            target_state = throttling_limit;
      }
      return acpi_processor_set_throttling(pr, target_state);
}

/*
 * _PTC - Processor Throttling Control (and status) register location
 */
static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
{
      int result = 0;
      acpi_status status = 0;
      struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
      union acpi_object *ptc = NULL;
      union acpi_object obj = { 0 };
      struct acpi_processor_throttling *throttling;

      status = acpi_evaluate_object(pr->handle, "_PTC", NULL, &buffer);
      if (ACPI_FAILURE(status)) {
            if (status != AE_NOT_FOUND) {
                  ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTC"));
            }
            return -ENODEV;
      }

      ptc = (union acpi_object *)buffer.pointer;
      if (!ptc || (ptc->type != ACPI_TYPE_PACKAGE)
          || (ptc->package.count != 2)) {
            printk(KERN_ERR PREFIX "Invalid _PTC data\n");
            result = -EFAULT;
            goto end;
      }

      /*
       * control_register
       */

      obj = ptc->package.elements[0];

      if ((obj.type != ACPI_TYPE_BUFFER)
          || (obj.buffer.length < sizeof(struct acpi_ptc_register))
          || (obj.buffer.pointer == NULL)) {
            printk(KERN_ERR PREFIX
                   "Invalid _PTC data (control_register)\n");
            result = -EFAULT;
            goto end;
      }
      memcpy(&pr->throttling.control_register, obj.buffer.pointer,
             sizeof(struct acpi_ptc_register));

      /*
       * status_register
       */

      obj = ptc->package.elements[1];

      if ((obj.type != ACPI_TYPE_BUFFER)
          || (obj.buffer.length < sizeof(struct acpi_ptc_register))
          || (obj.buffer.pointer == NULL)) {
            printk(KERN_ERR PREFIX "Invalid _PTC data (status_register)\n");
            result = -EFAULT;
            goto end;
      }

      memcpy(&pr->throttling.status_register, obj.buffer.pointer,
             sizeof(struct acpi_ptc_register));

      throttling = &pr->throttling;

      if ((throttling->control_register.bit_width +
            throttling->control_register.bit_offset) > 32) {
            printk(KERN_ERR PREFIX "Invalid _PTC control register\n");
            result = -EFAULT;
            goto end;
      }

      if ((throttling->status_register.bit_width +
            throttling->status_register.bit_offset) > 32) {
            printk(KERN_ERR PREFIX "Invalid _PTC status register\n");
            result = -EFAULT;
            goto end;
      }

      end:
      kfree(buffer.pointer);

      return result;
}

/*
 * _TSS - Throttling Supported States
 */
static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
{
      int result = 0;
      acpi_status status = AE_OK;
      struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
      struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
      struct acpi_buffer state = { 0, NULL };
      union acpi_object *tss = NULL;
      int i;

      status = acpi_evaluate_object(pr->handle, "_TSS", NULL, &buffer);
      if (ACPI_FAILURE(status)) {
            if (status != AE_NOT_FOUND) {
                  ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSS"));
            }
            return -ENODEV;
      }

      tss = buffer.pointer;
      if (!tss || (tss->type != ACPI_TYPE_PACKAGE)) {
            printk(KERN_ERR PREFIX "Invalid _TSS data\n");
            result = -EFAULT;
            goto end;
      }

      ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
                    tss->package.count));

      pr->throttling.state_count = tss->package.count;
      pr->throttling.states_tss =
          kmalloc(sizeof(struct acpi_processor_tx_tss) * tss->package.count,
                GFP_KERNEL);
      if (!pr->throttling.states_tss) {
            result = -ENOMEM;
            goto end;
      }

      for (i = 0; i < pr->throttling.state_count; i++) {

            struct acpi_processor_tx_tss *tx =
                (struct acpi_processor_tx_tss *)&(pr->throttling.
                                          states_tss[i]);

            state.length = sizeof(struct acpi_processor_tx_tss);
            state.pointer = tx;

            ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));

            status = acpi_extract_package(&(tss->package.elements[i]),
                                    &format, &state);
            if (ACPI_FAILURE(status)) {
                  ACPI_EXCEPTION((AE_INFO, status, "Invalid _TSS data"));
                  result = -EFAULT;
                  kfree(pr->throttling.states_tss);
                  goto end;
            }

            if (!tx->freqpercentage) {
                  printk(KERN_ERR PREFIX
                         "Invalid _TSS data: freq is zero\n");
                  result = -EFAULT;
                  kfree(pr->throttling.states_tss);
                  goto end;
            }
      }

      end:
      kfree(buffer.pointer);

      return result;
}

/*
 * _TSD - T-State Dependencies
 */
static int acpi_processor_get_tsd(struct acpi_processor *pr)
{
      int result = 0;
      acpi_status status = AE_OK;
      struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
      struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
      struct acpi_buffer state = { 0, NULL };
      union acpi_object *tsd = NULL;
      struct acpi_tsd_package *pdomain;

      status = acpi_evaluate_object(pr->handle, "_TSD", NULL, &buffer);
      if (ACPI_FAILURE(status)) {
            if (status != AE_NOT_FOUND) {
                  ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSD"));
            }
            return -ENODEV;
      }

      tsd = buffer.pointer;
      if (!tsd || (tsd->type != ACPI_TYPE_PACKAGE)) {
            ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
            result = -EFAULT;
            goto end;
      }

      if (tsd->package.count != 1) {
            ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
            result = -EFAULT;
            goto end;
      }

      pdomain = &(pr->throttling.domain_info);

      state.length = sizeof(struct acpi_tsd_package);
      state.pointer = pdomain;

      status = acpi_extract_package(&(tsd->package.elements[0]),
                              &format, &state);
      if (ACPI_FAILURE(status)) {
            ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
            result = -EFAULT;
            goto end;
      }

      if (pdomain->num_entries != ACPI_TSD_REV0_ENTRIES) {
            ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:num_entries\n"));
            result = -EFAULT;
            goto end;
      }

      if (pdomain->revision != ACPI_TSD_REV0_REVISION) {
            ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:revision\n"));
            result = -EFAULT;
            goto end;
      }

      end:
      kfree(buffer.pointer);
      return result;
}

/* --------------------------------------------------------------------------
                              Throttling Control
   -------------------------------------------------------------------------- */
static int acpi_processor_get_throttling_fadt(struct acpi_processor *pr)
{
      int state = 0;
      u32 value = 0;
      u32 duty_mask = 0;
      u32 duty_value = 0;

      if (!pr)
            return -EINVAL;

      if (!pr->flags.throttling)
            return -ENODEV;

      pr->throttling.state = 0;

      duty_mask = pr->throttling.state_count - 1;

      duty_mask <<= pr->throttling.duty_offset;

      local_irq_disable();

      value = inl(pr->throttling.address);

      /*
       * Compute the current throttling state when throttling is enabled
       * (bit 4 is on).
       */
      if (value & 0x10) {
            duty_value = value & duty_mask;
            duty_value >>= pr->throttling.duty_offset;

            if (duty_value)
                  state = pr->throttling.state_count - duty_value;
      }

      pr->throttling.state = state;

      local_irq_enable();

      ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                    "Throttling state is T%d (%d%% throttling applied)\n",
                    state, pr->throttling.states[state].performance));

      return 0;
}

#ifdef CONFIG_X86
static int acpi_throttling_rdmsr(struct acpi_processor *pr,
                              acpi_integer * value)
{
      struct cpuinfo_x86 *c;
      u64 msr_high, msr_low;
      unsigned int cpu;
      u64 msr = 0;
      int ret = -1;

      cpu = pr->id;
      c = &cpu_data(cpu);

      if ((c->x86_vendor != X86_VENDOR_INTEL) ||
            !cpu_has(c, X86_FEATURE_ACPI)) {
            printk(KERN_ERR PREFIX
                  "HARDWARE addr space,NOT supported yet\n");
      } else {
            msr_low = 0;
            msr_high = 0;
            rdmsr_safe(MSR_IA32_THERM_CONTROL,
                  (u32 *)&msr_low , (u32 *) &msr_high);
            msr = (msr_high << 32) | msr_low;
            *value = (acpi_integer) msr;
            ret = 0;
      }
      return ret;
}

static int acpi_throttling_wrmsr(struct acpi_processor *pr, acpi_integer value)
{
      struct cpuinfo_x86 *c;
      unsigned int cpu;
      int ret = -1;
      u64 msr;

      cpu = pr->id;
      c = &cpu_data(cpu);

      if ((c->x86_vendor != X86_VENDOR_INTEL) ||
            !cpu_has(c, X86_FEATURE_ACPI)) {
            printk(KERN_ERR PREFIX
                  "HARDWARE addr space,NOT supported yet\n");
      } else {
            msr = value;
            wrmsr_safe(MSR_IA32_THERM_CONTROL,
                  msr & 0xffffffff, msr >> 32);
            ret = 0;
      }
      return ret;
}
#else
static int acpi_throttling_rdmsr(struct acpi_processor *pr,
                        acpi_integer * value)
{
      printk(KERN_ERR PREFIX
            "HARDWARE addr space,NOT supported yet\n");
      return -1;
}

static int acpi_throttling_wrmsr(struct acpi_processor *pr, acpi_integer value)
{
      printk(KERN_ERR PREFIX
            "HARDWARE addr space,NOT supported yet\n");
      return -1;
}
#endif

static int acpi_read_throttling_status(struct acpi_processor *pr,
                              acpi_integer *value)
{
      u32 bit_width, bit_offset;
      u64 ptc_value;
      u64 ptc_mask;
      struct acpi_processor_throttling *throttling;
      int ret = -1;

      throttling = &pr->throttling;
      switch (throttling->status_register.space_id) {
      case ACPI_ADR_SPACE_SYSTEM_IO:
            ptc_value = 0;
            bit_width = throttling->status_register.bit_width;
            bit_offset = throttling->status_register.bit_offset;

            acpi_os_read_port((acpi_io_address) throttling->status_register.
                          address, (u32 *) &ptc_value,
                          (u32) (bit_width + bit_offset));
            ptc_mask = (1 << bit_width) - 1;
            *value = (acpi_integer) ((ptc_value >> bit_offset) & ptc_mask);
            ret = 0;
            break;
      case ACPI_ADR_SPACE_FIXED_HARDWARE:
            ret = acpi_throttling_rdmsr(pr, value);
            break;
      default:
            printk(KERN_ERR PREFIX "Unknown addr space %d\n",
                   (u32) (throttling->status_register.space_id));
      }
      return ret;
}

static int acpi_write_throttling_state(struct acpi_processor *pr,
                        acpi_integer value)
{
      u32 bit_width, bit_offset;
      u64 ptc_value;
      u64 ptc_mask;
      struct acpi_processor_throttling *throttling;
      int ret = -1;

      throttling = &pr->throttling;
      switch (throttling->control_register.space_id) {
      case ACPI_ADR_SPACE_SYSTEM_IO:
            bit_width = throttling->control_register.bit_width;
            bit_offset = throttling->control_register.bit_offset;
            ptc_mask = (1 << bit_width) - 1;
            ptc_value = value & ptc_mask;

            acpi_os_write_port((acpi_io_address) throttling->
                              control_register.address,
                              (u32) (ptc_value << bit_offset),
                              (u32) (bit_width + bit_offset));
            ret = 0;
            break;
      case ACPI_ADR_SPACE_FIXED_HARDWARE:
            ret = acpi_throttling_wrmsr(pr, value);
            break;
      default:
            printk(KERN_ERR PREFIX "Unknown addr space %d\n",
                   (u32) (throttling->control_register.space_id));
      }
      return ret;
}

static int acpi_get_throttling_state(struct acpi_processor *pr,
                        acpi_integer value)
{
      int i;

      for (i = 0; i < pr->throttling.state_count; i++) {
            struct acpi_processor_tx_tss *tx =
                (struct acpi_processor_tx_tss *)&(pr->throttling.
                                          states_tss[i]);
            if (tx->control == value)
                  break;
      }
      if (i > pr->throttling.state_count)
            i = -1;
      return i;
}

static int acpi_get_throttling_value(struct acpi_processor *pr,
                  int state, acpi_integer *value)
{
      int ret = -1;

      if (state >= 0 && state <= pr->throttling.state_count) {
            struct acpi_processor_tx_tss *tx =
                (struct acpi_processor_tx_tss *)&(pr->throttling.
                                          states_tss[state]);
            *value = tx->control;
            ret = 0;
      }
      return ret;
}

static int acpi_processor_get_throttling_ptc(struct acpi_processor *pr)
{
      int state = 0;
      int ret;
      acpi_integer value;

      if (!pr)
            return -EINVAL;

      if (!pr->flags.throttling)
            return -ENODEV;

      pr->throttling.state = 0;

      value = 0;
      ret = acpi_read_throttling_status(pr, &value);
      if (ret >= 0) {
            state = acpi_get_throttling_state(pr, value);
            pr->throttling.state = state;
      }

      return 0;
}

static int acpi_processor_get_throttling(struct acpi_processor *pr)
{
      cpumask_t saved_mask;
      int ret;

      /*
       * Migrate task to the cpu pointed by pr.
       */
      saved_mask = current->cpus_allowed;
      set_cpus_allowed(current, cpumask_of_cpu(pr->id));
      ret = pr->throttling.acpi_processor_get_throttling(pr);
      /* restore the previous state */
      set_cpus_allowed(current, saved_mask);

      return ret;
}

static int acpi_processor_get_fadt_info(struct acpi_processor *pr)
{
      int i, step;

      if (!pr->throttling.address) {
            ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n"));
            return -EINVAL;
      } else if (!pr->throttling.duty_width) {
            ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n"));
            return -EINVAL;
      }
      /* TBD: Support duty_cycle values that span bit 4. */
      else if ((pr->throttling.duty_offset + pr->throttling.duty_width) > 4) {
            printk(KERN_WARNING PREFIX "duty_cycle spans bit 4\n");
            return -EINVAL;
      }

      pr->throttling.state_count = 1 << acpi_gbl_FADT.duty_width;

      /*
       * Compute state values. Note that throttling displays a linear power
       * performance relationship (at 50% performance the CPU will consume
       * 50% power).  Values are in 1/10th of a percent to preserve accuracy.
       */

      step = (1000 / pr->throttling.state_count);

      for (i = 0; i < pr->throttling.state_count; i++) {
            pr->throttling.states[i].performance = 1000 - step * i;
            pr->throttling.states[i].power = 1000 - step * i;
      }
      return 0;
}

static int acpi_processor_set_throttling_fadt(struct acpi_processor *pr,
                                    int state)
{
      u32 value = 0;
      u32 duty_mask = 0;
      u32 duty_value = 0;

      if (!pr)
            return -EINVAL;

      if ((state < 0) || (state > (pr->throttling.state_count - 1)))
            return -EINVAL;

      if (!pr->flags.throttling)
            return -ENODEV;

      if (state == pr->throttling.state)
            return 0;

      if (state < pr->throttling_platform_limit)
            return -EPERM;
      /*
       * Calculate the duty_value and duty_mask.
       */
      if (state) {
            duty_value = pr->throttling.state_count - state;

            duty_value <<= pr->throttling.duty_offset;

            /* Used to clear all duty_value bits */
            duty_mask = pr->throttling.state_count - 1;

            duty_mask <<= acpi_gbl_FADT.duty_offset;
            duty_mask = ~duty_mask;
      }

      local_irq_disable();

      /*
       * Disable throttling by writing a 0 to bit 4.  Note that we must
       * turn it off before you can change the duty_value.
       */
      value = inl(pr->throttling.address);
      if (value & 0x10) {
            value &= 0xFFFFFFEF;
            outl(value, pr->throttling.address);
      }

      /*
       * Write the new duty_value and then enable throttling.  Note
       * that a state value of 0 leaves throttling disabled.
       */
      if (state) {
            value &= duty_mask;
            value |= duty_value;
            outl(value, pr->throttling.address);

            value |= 0x00000010;
            outl(value, pr->throttling.address);
      }

      pr->throttling.state = state;

      local_irq_enable();

      ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                    "Throttling state set to T%d (%d%%)\n", state,
                    (pr->throttling.states[state].performance ? pr->
                     throttling.states[state].performance / 10 : 0)));

      return 0;
}

static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
                                   int state)
{
      int ret;
      acpi_integer value;

      if (!pr)
            return -EINVAL;

      if ((state < 0) || (state > (pr->throttling.state_count - 1)))
            return -EINVAL;

      if (!pr->flags.throttling)
            return -ENODEV;

      if (state == pr->throttling.state)
            return 0;

      if (state < pr->throttling_platform_limit)
            return -EPERM;

      value = 0;
      ret = acpi_get_throttling_value(pr, state, &value);
      if (ret >= 0) {
            acpi_write_throttling_state(pr, value);
            pr->throttling.state = state;
      }

      return 0;
}

int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
{
      cpumask_t saved_mask;
      int ret;
      /*
       * Migrate task to the cpu pointed by pr.
       */
      saved_mask = current->cpus_allowed;
      set_cpus_allowed(current, cpumask_of_cpu(pr->id));
      ret = pr->throttling.acpi_processor_set_throttling(pr, state);
      /* restore the previous state */
      set_cpus_allowed(current, saved_mask);
      return ret;
}

int acpi_processor_get_throttling_info(struct acpi_processor *pr)
{
      int result = 0;

      ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                    "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
                    pr->throttling.address,
                    pr->throttling.duty_offset,
                    pr->throttling.duty_width));

      if (!pr)
            return -EINVAL;

      /*
       * Evaluate _PTC, _TSS and _TPC
       * They must all be present or none of them can be used.
       */
      if (acpi_processor_get_throttling_control(pr) ||
            acpi_processor_get_throttling_states(pr) ||
            acpi_processor_get_platform_limit(pr))
      {
            pr->throttling.acpi_processor_get_throttling =
                &acpi_processor_get_throttling_fadt;
            pr->throttling.acpi_processor_set_throttling =
                &acpi_processor_set_throttling_fadt;
            if (acpi_processor_get_fadt_info(pr))
                  return 0;
      } else {
            pr->throttling.acpi_processor_get_throttling =
                &acpi_processor_get_throttling_ptc;
            pr->throttling.acpi_processor_set_throttling =
                &acpi_processor_set_throttling_ptc;
      }

      acpi_processor_get_tsd(pr);

      /*
       * PIIX4 Errata: We don't support throttling on the original PIIX4.
       * This shouldn't be an issue as few (if any) mobile systems ever
       * used this part.
       */
      if (errata.piix4.throttle) {
            ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "Throttling not supported on PIIX4 A- or B-step\n"));
            return 0;
      }

      ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
                    pr->throttling.state_count));

      pr->flags.throttling = 1;

      /*
       * Disable throttling (if enabled).  We'll let subsequent policy (e.g.
       * thermal) decide to lower performance if it so chooses, but for now
       * we'll crank up the speed.
       */

      result = acpi_processor_get_throttling(pr);
      if (result)
            goto end;

      if (pr->throttling.state) {
            ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                          "Disabling throttling (was T%d)\n",
                          pr->throttling.state));
            result = acpi_processor_set_throttling(pr, 0);
            if (result)
                  goto end;
      }

      end:
      if (result)
            pr->flags.throttling = 0;

      return result;
}

/* proc interface */

static int acpi_processor_throttling_seq_show(struct seq_file *seq,
                                    void *offset)
{
      struct acpi_processor *pr = seq->private;
      int i = 0;
      int result = 0;

      if (!pr)
            goto end;

      if (!(pr->throttling.state_count > 0)) {
            seq_puts(seq, "<not supported>\n");
            goto end;
      }

      result = acpi_processor_get_throttling(pr);

      if (result) {
            seq_puts(seq,
                   "Could not determine current throttling state.\n");
            goto end;
      }

      seq_printf(seq, "state count:             %d\n"
               "active state:            T%d\n"
               "state available: T%d to T%d\n",
               pr->throttling.state_count, pr->throttling.state,
               pr->throttling_platform_limit,
               pr->throttling.state_count - 1);

      seq_puts(seq, "states:\n");
      if (pr->throttling.acpi_processor_get_throttling ==
                  acpi_processor_get_throttling_fadt) {
            for (i = 0; i < pr->throttling.state_count; i++)
                  seq_printf(seq, "   %cT%d:                  %02d%%\n",
                           (i == pr->throttling.state ? '*' : ' '), i,
                           (pr->throttling.states[i].performance ? pr->
                            throttling.states[i].performance / 10 : 0));
      } else {
            for (i = 0; i < pr->throttling.state_count; i++)
                  seq_printf(seq, "   %cT%d:                  %02d%%\n",
                           (i == pr->throttling.state ? '*' : ' '), i,
                           (int)pr->throttling.states_tss[i].
                           freqpercentage);
      }

      end:
      return 0;
}

static int acpi_processor_throttling_open_fs(struct inode *inode,
                                   struct file *file)
{
      return single_open(file, acpi_processor_throttling_seq_show,
                     PDE(inode)->data);
}

static ssize_t acpi_processor_write_throttling(struct file *file,
                                     const char __user * buffer,
                                     size_t count, loff_t * data)
{
      int result = 0;
      struct seq_file *m = file->private_data;
      struct acpi_processor *pr = m->private;
      char state_string[12] = { '\0' };

      if (!pr || (count > sizeof(state_string) - 1))
            return -EINVAL;

      if (copy_from_user(state_string, buffer, count))
            return -EFAULT;

      state_string[count] = '\0';

      result = acpi_processor_set_throttling(pr,
                                     simple_strtoul(state_string,
                                                NULL, 0));
      if (result)
            return result;

      return count;
}

struct file_operations acpi_processor_throttling_fops = {
      .open = acpi_processor_throttling_open_fs,
      .read = seq_read,
      .write = acpi_processor_write_throttling,
      .llseek = seq_lseek,
      .release = single_release,
};

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