text: /*
   * acpi-cpufreq.c - ACPI Processor P-States Driver
   *
   *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   *  Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
   *  Copyright (C) 2006       Denis Sadykov <denis.m.sadykov@intel.com>
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   *  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/smp.h>
  #include <linux/sched.h>
  #include <linux/cpufreq.h>
  #include <linux/compiler.h>
  #include <linux/dmi.h>
  #include <linux/slab.h>
  
  #include <linux/acpi.h>
  #include <linux/io.h>
  #include <linux/delay.h>
  #include <linux/uaccess.h>
  
  #include <acpi/processor.h>
  
  #include <asm/msr.h>
  #include <asm/processor.h>
  #include <asm/cpufeature.h>
  #include "mperf.h"
  
  #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
  		"acpi-cpufreq", msg)
  
  MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
  MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  MODULE_LICENSE("GPL");
  
  enum {
  	UNDEFINED_CAPABLE = 0,
  	SYSTEM_INTEL_MSR_CAPABLE,
  	SYSTEM_IO_CAPABLE,
  };
  
  #define INTEL_MSR_RANGE		(0xffff)
  
  struct acpi_cpufreq_data {
  	struct acpi_processor_performance *acpi_data;
  	struct cpufreq_frequency_table *freq_table;
  	unsigned int resume;
  	unsigned int cpu_feature;
  };
  
  static DEFINE_PER_CPU(struct acpi_cpufreq_data *, acfreq_data);
  
  /* acpi_perf_data is a pointer to percpu data. */
  static struct acpi_processor_performance __percpu *acpi_perf_data;
  
  static struct cpufreq_driver acpi_cpufreq_driver;
  
  static unsigned int acpi_pstate_strict;
  
  static int check_est_cpu(unsigned int cpuid)
  {
  	struct cpuinfo_x86 *cpu = &cpu_data(cpuid);
  
  	return cpu_has(cpu, X86_FEATURE_EST);
  }
  
  static unsigned extract_io(u32 value, struct acpi_cpufreq_data *data)
  {
  	struct acpi_processor_performance *perf;
  	int i;
  
  	perf = data->acpi_data;
  
  	for (i = 0; i < perf->state_count; i++) {
  		if (value == perf->states[i].status)
  			return data->freq_table[i].frequency;
  	}
  	return 0;
  }
  
  static unsigned extract_msr(u32 msr, struct acpi_cpufreq_data *data)
  {
  	int i;
  	struct acpi_processor_performance *perf;
  
  	msr &= INTEL_MSR_RANGE;
  	perf = data->acpi_data;
  
  	for (i = 0; data->freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
  		if (msr == perf->states[data->freq_table[i].index].status)
  			return data->freq_table[i].frequency;
  	}
  	return data->freq_table[0].frequency;
  }
  
  static unsigned extract_freq(u32 val, struct acpi_cpufreq_data *data)
  {
  	switch (data->cpu_feature) {
  	case SYSTEM_INTEL_MSR_CAPABLE:
  		return extract_msr(val, data);
  	case SYSTEM_IO_CAPABLE:
  		return extract_io(val, data);
  	default:
  		return 0;
  	}
  }
  
  struct msr_addr {
  	u32 reg;
  };
  
  struct io_addr {
  	u16 port;
  	u8 bit_width;
  };
  
  struct drv_cmd {
  	unsigned int type;
  	const struct cpumask *mask;
  	union {
  		struct msr_addr msr;
  		struct io_addr io;
  	} addr;
  	u32 val;
  };
  
  /* Called via smp_call_function_single(), on the target CPU */
  static void do_drv_read(void *_cmd)
  {
  	struct drv_cmd *cmd = _cmd;
  	u32 h;
  
  	switch (cmd->type) {
  	case SYSTEM_INTEL_MSR_CAPABLE:
  		rdmsr(cmd->addr.msr.reg, cmd->val, h);
  		break;
  	case SYSTEM_IO_CAPABLE:
  		acpi_os_read_port((acpi_io_address)cmd->addr.io.port,
  				&cmd->val,
  				(u32)cmd->addr.io.bit_width);
  		break;
  	default:
  		break;
  	}
  }
  
  /* Called via smp_call_function_many(), on the target CPUs */
  static void do_drv_write(void *_cmd)
  {
  	struct drv_cmd *cmd = _cmd;
  	u32 lo, hi;
  
  	switch (cmd->type) {
  	case SYSTEM_INTEL_MSR_CAPABLE:
  		rdmsr(cmd->addr.msr.reg, lo, hi);
  		lo = (lo & ~INTEL_MSR_RANGE) | (cmd->val & INTEL_MSR_RANGE);
  		wrmsr(cmd->addr.msr.reg, lo, hi);
  		break;
  	case SYSTEM_IO_CAPABLE:
  		acpi_os_write_port((acpi_io_address)cmd->addr.io.port,
  				cmd->val,
  				(u32)cmd->addr.io.bit_width);
  		break;
  	default:
  		break;
  	}
  }
  
  static void drv_read(struct drv_cmd *cmd)
  {
  	int err;
  	cmd->val = 0;
  
  	err = smp_call_function_any(cmd->mask, do_drv_read, cmd, 1);
  	WARN_ON_ONCE(err);	/* smp_call_function_any() was buggy? */
  }
  
  static void drv_write(struct drv_cmd *cmd)
  {
  	int this_cpu;
  
  	this_cpu = get_cpu();
  	if (cpumask_test_cpu(this_cpu, cmd->mask))
  		do_drv_write(cmd);
  	smp_call_function_many(cmd->mask, do_drv_write, cmd, 1);
  	put_cpu();
  }
  
  static u32 get_cur_val(const struct cpumask *mask)
  {
  	struct acpi_processor_performance *perf;
  	struct drv_cmd cmd;
  
  	if (unlikely(cpumask_empty(mask)))
  		return 0;
  
  	switch (per_cpu(acfreq_data, cpumask_first(mask))->cpu_feature) {
  	case SYSTEM_INTEL_MSR_CAPABLE:
  		cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
  		cmd.addr.msr.reg = MSR_IA32_PERF_STATUS;
  		break;
  	case SYSTEM_IO_CAPABLE:
  		cmd.type = SYSTEM_IO_CAPABLE;
  		perf = per_cpu(acfreq_data, cpumask_first(mask))->acpi_data;
  		cmd.addr.io.port = perf->control_register.address;
  		cmd.addr.io.bit_width = perf->control_register.bit_width;
  		break;
  	default:
  		return 0;
  	}
  
  	cmd.mask = mask;
  	drv_read(&cmd);
  
  	dprintk("get_cur_val = %u\n", cmd.val);
  
  	return cmd.val;
  }
  
  static unsigned int get_cur_freq_on_cpu(unsigned int cpu)
  {
  	struct acpi_cpufreq_data *data = per_cpu(acfreq_data, cpu);
  	unsigned int freq;
  	unsigned int cached_freq;
  
  	dprintk("get_cur_freq_on_cpu (%d)\n", cpu);
  
  	if (unlikely(data == NULL ||
  		     data->acpi_data == NULL || data->freq_table == NULL)) {
  		return 0;
  	}
  
  	cached_freq = data->freq_table[data->acpi_data->state].frequency;
  	freq = extract_freq(get_cur_val(cpumask_of(cpu)), data);
  	if (freq != cached_freq) {
  		/*
  		 * The dreaded BIOS frequency change behind our back.
  		 * Force set the frequency on next target call.
  		 */
  		data->resume = 1;
  	}
  
  	dprintk("cur freq = %u\n", freq);
  
  	return freq;
  }
  
  static unsigned int check_freqs(const struct cpumask *mask, unsigned int freq,
  				struct acpi_cpufreq_data *data)
  {
  	unsigned int cur_freq;
  	unsigned int i;
  
  	for (i = 0; i < 100; i++) {
  		cur_freq = extract_freq(get_cur_val(mask), data);
  		if (cur_freq == freq)
  			return 1;
  		udelay(10);
  	}
  	return 0;
  }
  
  static int acpi_cpufreq_target(struct cpufreq_policy *policy,
  			       unsigned int target_freq, unsigned int relation)
  {
  	struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
  	struct acpi_processor_performance *perf;
  	struct cpufreq_freqs freqs;
  	struct drv_cmd cmd;
  	unsigned int next_state = 0; /* Index into freq_table */
  	unsigned int next_perf_state = 0; /* Index into perf table */
  	unsigned int i;
  	int result = 0;
  
  	dprintk("acpi_cpufreq_target %d (%d)\n", target_freq, policy->cpu);
  
  	if (unlikely(data == NULL ||
  	     data->acpi_data == NULL || data->freq_table == NULL)) {
  		return -ENODEV;
  	}
  
  	perf = data->acpi_data;
  	result = cpufreq_frequency_table_target(policy,
  						data->freq_table,
  						target_freq,
  						relation, &next_state);
  	if (unlikely(result)) {
  		result = -ENODEV;
  		goto out;
  	}
  
  	next_perf_state = data->freq_table[next_state].index;
  	if (perf->state == next_perf_state) {
  		if (unlikely(data->resume)) {
  			dprintk("Called after resume, resetting to P%d\n",
  				next_perf_state);
  			data->resume = 0;
  		} else {
  			dprintk("Already at target state (P%d)\n",
  				next_perf_state);
  			goto out;
  		}
  	}
  
  	switch (data->cpu_feature) {
  	case SYSTEM_INTEL_MSR_CAPABLE:
  		cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
  		cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
  		cmd.val = (u32) perf->states[next_perf_state].control;
  		break;
  	case SYSTEM_IO_CAPABLE:
  		cmd.type = SYSTEM_IO_CAPABLE;
  		cmd.addr.io.port = perf->control_register.address;
  		cmd.addr.io.bit_width = perf->control_register.bit_width;
  		cmd.val = (u32) perf->states[next_perf_state].control;
  		break;
  	default:
  		result = -ENODEV;
  		goto out;
  	}
  
  	/* cpufreq holds the hotplug lock, so we are safe from here on */
  	if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
  		cmd.mask = policy->cpus;
  	else
  		cmd.mask = cpumask_of(policy->cpu);
  
  	freqs.old = perf->states[perf->state].core_frequency * 1000;
  	freqs.new = data->freq_table[next_state].frequency;
  	for_each_cpu(i, policy->cpus) {
  		freqs.cpu = i;
  		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
  	}
  
  	drv_write(&cmd);
  
  	if (acpi_pstate_strict) {
  		if (!check_freqs(cmd.mask, freqs.new, data)) {
  			dprintk("acpi_cpufreq_target failed (%d)\n",
  				policy->cpu);
  			result = -EAGAIN;
  			goto out;
  		}
  	}
  
  	for_each_cpu(i, policy->cpus) {
  		freqs.cpu = i;
  		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
  	}
  	perf->state = next_perf_state;
  
  out:
  	return result;
  }
  
  static int acpi_cpufreq_verify(struct cpufreq_policy *policy)
  {
  	struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
  
  	dprintk("acpi_cpufreq_verify\n");
  
  	return cpufreq_frequency_table_verify(policy, data->freq_table);
  }
  
  static unsigned long
  acpi_cpufreq_guess_freq(struct acpi_cpufreq_data *data, unsigned int cpu)
  {
  	struct acpi_processor_performance *perf = data->acpi_data;
  
  	if (cpu_khz) {
  		/* search the closest match to cpu_khz */
  		unsigned int i;
  		unsigned long freq;
  		unsigned long freqn = perf->states[0].core_frequency * 1000;
  
  		for (i = 0; i < (perf->state_count-1); i++) {
  			freq = freqn;
  			freqn = perf->states[i+1].core_frequency * 1000;
  			if ((2 * cpu_khz) > (freqn + freq)) {
  				perf->state = i;
  				return freq;
  			}
  		}
  		perf->state = perf->state_count-1;
  		return freqn;
  	} else {
  		/* assume CPU is at P0... */
  		perf->state = 0;
  		return perf->states[0].core_frequency * 1000;
  	}
  }
  
  static void free_acpi_perf_data(void)
  {
  	unsigned int i;
  
  	/* Freeing a NULL pointer is OK, and alloc_percpu zeroes. */
  	for_each_possible_cpu(i)
  		free_cpumask_var(per_cpu_ptr(acpi_perf_data, i)
  				 ->shared_cpu_map);
  	free_percpu(acpi_perf_data);
  }
  
  /*
   * acpi_cpufreq_early_init - initialize ACPI P-States library
   *
   * Initialize the ACPI P-States library (drivers/acpi/processor_perflib.c)
   * in order to determine correct frequency and voltage pairings. We can
   * do _PDC and _PSD and find out the processor dependency for the
   * actual init that will happen later...
   */
  static int __init acpi_cpufreq_early_init(void)
  {
  	unsigned int i;
  	dprintk("acpi_cpufreq_early_init\n");
  
  	acpi_perf_data = alloc_percpu(struct acpi_processor_performance);
  	if (!acpi_perf_data) {
  		dprintk("Memory allocation error for acpi_perf_data.\n");
  		return -ENOMEM;
  	}
  	for_each_possible_cpu(i) {
  		if (!zalloc_cpumask_var_node(
  			&per_cpu_ptr(acpi_perf_data, i)->shared_cpu_map,
  			GFP_KERNEL, cpu_to_node(i))) {
  
  			/* Freeing a NULL pointer is OK: alloc_percpu zeroes. */
  			free_acpi_perf_data();
  			return -ENOMEM;
  		}
  	}
  
  	/* Do initialization in ACPI core */
  	acpi_processor_preregister_performance(acpi_perf_data);
  	return 0;
  }
  
  #ifdef CONFIG_SMP
  /*
   * Some BIOSes do SW_ANY coordination internally, either set it up in hw
   * or do it in BIOS firmware and won't inform about it to OS. If not
   * detected, this has a side effect of making CPU run at a different speed
   * than OS intended it to run at. Detect it and handle it cleanly.
   */
  static int bios_with_sw_any_bug;
  
  static int sw_any_bug_found(const struct dmi_system_id *d)
  {
  	bios_with_sw_any_bug = 1;
  	return 0;
  }
  
  static const struct dmi_system_id sw_any_bug_dmi_table[] = {
  	{
  		.callback = sw_any_bug_found,
  		.ident = "Supermicro Server X6DLP",
  		.matches = {
  			DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
  			DMI_MATCH(DMI_BIOS_VERSION, "080010"),
  			DMI_MATCH(DMI_PRODUCT_NAME, "X6DLP"),
  		},
  	},
  	{ }
  };
  
  static int acpi_cpufreq_blacklist(struct cpuinfo_x86 *c)
  {
  	/* Intel Xeon Processor 7100 Series Specification Update
  	 * http://www.intel.com/Assets/PDF/specupdate/314554.pdf
  	 * AL30: A Machine Check Exception (MCE) Occurring during an
  	 * Enhanced Intel SpeedStep Technology Ratio Change May Cause
  	 * Both Processor Cores to Lock Up. */
  	if (c->x86_vendor == X86_VENDOR_INTEL) {
  		if ((c->x86 == 15) &&
  		    (c->x86_model == 6) &&
  		    (c->x86_mask == 8)) {
  			printk(KERN_INFO "acpi-cpufreq: Intel(R) "
  			    "Xeon(R) 7100 Errata AL30, processors may "
  			    "lock up on frequency changes: disabling "
  			    "acpi-cpufreq.\n");
  			return -ENODEV;
  		    }
  		}
  	return 0;
  }
  #endif
  
  static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
  {
  	unsigned int i;
  	unsigned int valid_states = 0;
  	unsigned int cpu = policy->cpu;
  	struct acpi_cpufreq_data *data;
  	unsigned int result = 0;
  	struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
  	struct acpi_processor_performance *perf;
  #ifdef CONFIG_SMP
  	static int blacklisted;
  #endif
  
  	dprintk("acpi_cpufreq_cpu_init\n");
  
  #ifdef CONFIG_SMP
  	if (blacklisted)
  		return blacklisted;
  	blacklisted = acpi_cpufreq_blacklist(c);
  	if (blacklisted)
  		return blacklisted;
  #endif
  
  	data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	data->acpi_data = per_cpu_ptr(acpi_perf_data, cpu);
  	per_cpu(acfreq_data, cpu) = data;
  
  	if (cpu_has(c, X86_FEATURE_CONSTANT_TSC))
  		acpi_cpufreq_driver.flags |= CPUFREQ_CONST_LOOPS;
  
  	result = acpi_processor_register_performance(data->acpi_data, cpu);
  	if (result)
  		goto err_free;
  
  	perf = data->acpi_data;
  	policy->shared_type = perf->shared_type;
  
  	/*
  	 * Will let policy->cpus know about dependency only when software
  	 * coordination is required.
  	 */
  	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL ||
  	    policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
  		cpumask_copy(policy->cpus, perf->shared_cpu_map);
  	}
  	cpumask_copy(policy->related_cpus, perf->shared_cpu_map);
  
  #ifdef CONFIG_SMP
  	dmi_check_system(sw_any_bug_dmi_table);
  	if (bios_with_sw_any_bug && cpumask_weight(policy->cpus) == 1) {
  		policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
  		cpumask_copy(policy->cpus, cpu_core_mask(cpu));
  	}
  #endif
  
  	/* capability check */
  	if (perf->state_count <= 1) {
  		dprintk("No P-States\n");
  		result = -ENODEV;
  		goto err_unreg;
  	}
  
  	if (perf->control_register.space_id != perf->status_register.space_id) {
  		result = -ENODEV;
  		goto err_unreg;
  	}
  
  	switch (perf->control_register.space_id) {
  	case ACPI_ADR_SPACE_SYSTEM_IO:
  		dprintk("SYSTEM IO addr space\n");
  		data->cpu_feature = SYSTEM_IO_CAPABLE;
  		break;
  	case ACPI_ADR_SPACE_FIXED_HARDWARE:
  		dprintk("HARDWARE addr space\n");
  		if (!check_est_cpu(cpu)) {
  			result = -ENODEV;
  			goto err_unreg;
  		}
  		data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
  		break;
  	default:
  		dprintk("Unknown addr space %d\n",
  			(u32) (perf->control_register.space_id));
  		result = -ENODEV;
  		goto err_unreg;
  	}
  
  	data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
  		    (perf->state_count+1), GFP_KERNEL);
  	if (!data->freq_table) {
  		result = -ENOMEM;
  		goto err_unreg;
  	}
  
  	/* detect transition latency */
  	policy->cpuinfo.transition_latency = 0;
  	for (i = 0; i < perf->state_count; i++) {
  		if ((perf->states[i].transition_latency * 1000) >
  		    policy->cpuinfo.transition_latency)
  			policy->cpuinfo.transition_latency =
  			    perf->states[i].transition_latency * 1000;
  	}
  
  	/* Check for high latency (>20uS) from buggy BIOSes, like on T42 */
  	if (perf->control_register.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
  	    policy->cpuinfo.transition_latency > 20 * 1000) {
  		policy->cpuinfo.transition_latency = 20 * 1000;
  		printk_once(KERN_INFO
  			    "P-state transition latency capped at 20 uS\n");
  	}
  
  	/* table init */
  	for (i = 0; i < perf->state_count; i++) {
  		if (i > 0 && perf->states[i].core_frequency >=
  		    data->freq_table[valid_states-1].frequency / 1000)
  			continue;
  
  		data->freq_table[valid_states].index = i;
  		data->freq_table[valid_states].frequency =
  		    perf->states[i].core_frequency * 1000;
  		valid_states++;
  	}
  	data->freq_table[valid_states].frequency = CPUFREQ_TABLE_END;
  	perf->state = 0;
  
  	result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
  	if (result)
  		goto err_freqfree;
  
  	if (perf->states[0].core_frequency * 1000 != policy->cpuinfo.max_freq)
  		printk(KERN_WARNING FW_WARN "P-state 0 is not max freq\n");
  
  	switch (perf->control_register.space_id) {
  	case ACPI_ADR_SPACE_SYSTEM_IO:
  		/* Current speed is unknown and not detectable by IO port */
  		policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
  		break;
  	case ACPI_ADR_SPACE_FIXED_HARDWARE:
  		acpi_cpufreq_driver.get = get_cur_freq_on_cpu;
  		policy->cur = get_cur_freq_on_cpu(cpu);
  		break;
  	default:
  		break;
  	}
  
  	/* notify BIOS that we exist */
  	acpi_processor_notify_smm(THIS_MODULE);
  
  	/* Check for APERF/MPERF support in hardware */
  	if (cpu_has(c, X86_FEATURE_APERFMPERF))
  		acpi_cpufreq_driver.getavg = cpufreq_get_measured_perf;
  
  	dprintk("CPU%u - ACPI performance management activated.\n", cpu);
  	for (i = 0; i < perf->state_count; i++)
  		dprintk("     %cP%d: %d MHz, %d mW, %d uS\n",
  			(i == perf->state ? '*' : ' '), i,
  			(u32) perf->states[i].core_frequency,
  			(u32) perf->states[i].power,
  			(u32) perf->states[i].transition_latency);
  
  	cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
  
  	/*
  	 * the first call to ->target() should result in us actually
  	 * writing something to the appropriate registers.
  	 */
  	data->resume = 1;
  
  	return result;
  
  err_freqfree:
  	kfree(data->freq_table);
  err_unreg:
  	acpi_processor_unregister_performance(perf, cpu);
  err_free:
  	kfree(data);
  	per_cpu(acfreq_data, cpu) = NULL;
  
  	return result;
  }
  
  static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
  {
  	struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
  
  	dprintk("acpi_cpufreq_cpu_exit\n");
  
  	if (data) {
  		cpufreq_frequency_table_put_attr(policy->cpu);
  		per_cpu(acfreq_data, policy->cpu) = NULL;
  		acpi_processor_unregister_performance(data->acpi_data,
  						      policy->cpu);
  		kfree(data);
  	}
  
  	return 0;
  }
  
  static int acpi_cpufreq_resume(struct cpufreq_policy *policy)
  {
  	struct acpi_cpufreq_data *data = per_cpu(acfreq_data, policy->cpu);
  
  	dprintk("acpi_cpufreq_resume\n");
  
  	data->resume = 1;
  
  	return 0;
  }
  
  static struct freq_attr *acpi_cpufreq_attr[] = {
  	&cpufreq_freq_attr_scaling_available_freqs,
  	NULL,
  };
  
  static struct cpufreq_driver acpi_cpufreq_driver = {
  	.verify		= acpi_cpufreq_verify,
  	.target		= acpi_cpufreq_target,
  	.bios_limit	= acpi_processor_get_bios_limit,
  	.init		= acpi_cpufreq_cpu_init,
  	.exit		= acpi_cpufreq_cpu_exit,
  	.resume		= acpi_cpufreq_resume,
  	.name		= "acpi-cpufreq",
  	.owner		= THIS_MODULE,
  	.attr		= acpi_cpufreq_attr,
  };
  
  static int __init acpi_cpufreq_init(void)
  {
  	int ret;
  
  	if (acpi_disabled)
  		return 0;
  
  	dprintk("acpi_cpufreq_init\n");
  
  	ret = acpi_cpufreq_early_init();
  	if (ret)
  		return ret;
  
  	ret = cpufreq_register_driver(&acpi_cpufreq_driver);
  	if (ret)
  		free_acpi_perf_data();
  
  	return ret;
  }
  
  static void __exit acpi_cpufreq_exit(void)
  {
  	dprintk("acpi_cpufreq_exit\n");
  
  	cpufreq_unregister_driver(&acpi_cpufreq_driver);
  
  	free_percpu(acpi_perf_data);
  }
  
  module_param(acpi_pstate_strict, uint, 0644);
  MODULE_PARM_DESC(acpi_pstate_strict,
  	"value 0 or non-zero. non-zero -> strict ACPI checks are "
  	"performed during frequency changes.");
  
  late_initcall(acpi_cpufreq_init);
  module_exit(acpi_cpufreq_exit);
  
  MODULE_ALIAS("acpi");
  