speedstep-centrino.c

LINUX 2.6.17.4的源码

/*
 * centrino_cpu_init_acpi - register with ACPI P-States library
 *
 * Register with the ACPI P-States library (part of drivers/acpi/processor.c)
 * in order to determine correct frequency and voltage pairings by reading
 * the _PSS of the ACPI DSDT or SSDT tables.
 */
static int centrino_cpu_init_acpi(struct cpufreq_policy *policy)
{
	unsigned long			cur_freq;
	int				result = 0, i;
	unsigned int			cpu = policy->cpu;

	/* register with ACPI core */
	if (acpi_processor_register_performance(&p, cpu)) {
		dprintk(KERN_INFO PFX "obtaining ACPI data failed\n");
		return -EIO;
	}

	/* verify the acpi_data */
	if (p.state_count <= 1) {
		dprintk("No P-States\n");
		result = -ENODEV;
		goto err_unreg;
	}

	if ((p.control_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) ||
	    (p.status_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) {
		dprintk("Invalid control/status registers (%x - %x)\n",
			p.control_register.space_id, p.status_register.space_id);
		result = -EIO;
		goto err_unreg;
	}

	for (i=0; i<p.state_count; i++) {
		if (p.states[i].control != p.states[i].status) {
			dprintk("Different control (%llu) and status values (%llu)\n",
				p.states[i].control, p.states[i].status);
			result = -EINVAL;
			goto err_unreg;
		}

		if (!p.states[i].core_frequency) {
			dprintk("Zero core frequency for state %u\n", i);
			result = -EINVAL;
			goto err_unreg;
		}

		if (p.states[i].core_frequency > p.states[0].core_frequency) {
			dprintk("P%u has larger frequency (%llu) than P0 (%llu), skipping\n", i,
				p.states[i].core_frequency, p.states[0].core_frequency);
			p.states[i].core_frequency = 0;
			continue;
		}
	}

	centrino_model[cpu] = kzalloc(sizeof(struct cpu_model), GFP_KERNEL);
	if (!centrino_model[cpu]) {
		result = -ENOMEM;
		goto err_unreg;
	}

	centrino_model[cpu]->model_name=NULL;
	centrino_model[cpu]->max_freq = p.states[0].core_frequency * 1000;
	centrino_model[cpu]->op_points =  kmalloc(sizeof(struct cpufreq_frequency_table) *
					     (p.state_count + 1), GFP_KERNEL);
        if (!centrino_model[cpu]->op_points) {
                result = -ENOMEM;
                goto err_kfree;
        }

        for (i=0; i<p.state_count; i++) {
		centrino_model[cpu]->op_points[i].index = p.states[i].control;
		centrino_model[cpu]->op_points[i].frequency = p.states[i].core_frequency * 1000;
		dprintk("adding state %i with frequency %u and control value %04x\n", 
			i, centrino_model[cpu]->op_points[i].frequency, centrino_model[cpu]->op_points[i].index);
	}
	centrino_model[cpu]->op_points[p.state_count].frequency = CPUFREQ_TABLE_END;

	cur_freq = get_cur_freq(cpu);

	for (i=0; i<p.state_count; i++) {
		if (!p.states[i].core_frequency) {
			dprintk("skipping state %u\n", i);
			centrino_model[cpu]->op_points[i].frequency = CPUFREQ_ENTRY_INVALID;
			continue;
		}
		
		if (extract_clock(centrino_model[cpu]->op_points[i].index, cpu, 0) !=
		    (centrino_model[cpu]->op_points[i].frequency)) {
			dprintk("Invalid encoded frequency (%u vs. %u)\n",
				extract_clock(centrino_model[cpu]->op_points[i].index, cpu, 0),
				centrino_model[cpu]->op_points[i].frequency);
			result = -EINVAL;
			goto err_kfree_all;
		}

		if (cur_freq == centrino_model[cpu]->op_points[i].frequency)
			p.state = i;
	}

	/* notify BIOS that we exist */
	acpi_processor_notify_smm(THIS_MODULE);

	return 0;

 err_kfree_all:
	kfree(centrino_model[cpu]->op_points);
 err_kfree:
	kfree(centrino_model[cpu]);
 err_unreg:
	acpi_processor_unregister_performance(&p, cpu);
	dprintk(KERN_INFO PFX "invalid ACPI data\n");
	return (result);
}
#else
static inline int centrino_cpu_init_acpi(struct cpufreq_policy *policy) { return -ENODEV; }
#endif

static int centrino_cpu_init(struct cpufreq_policy *policy)
{
	struct cpuinfo_x86 *cpu = &cpu_data[policy->cpu];
	unsigned freq;
	unsigned l, h;
	int ret;
	int i;

	/* Only Intel makes Enhanced Speedstep-capable CPUs */
	if (cpu->x86_vendor != X86_VENDOR_INTEL || !cpu_has(cpu, X86_FEATURE_EST))
		return -ENODEV;

	if (cpu_has(cpu, X86_FEATURE_CONSTANT_TSC))
		centrino_driver.flags |= CPUFREQ_CONST_LOOPS;

	if (centrino_cpu_init_acpi(policy)) {
		if (policy->cpu != 0)
			return -ENODEV;

		for (i = 0; i < N_IDS; i++)
			if (centrino_verify_cpu_id(cpu, &cpu_ids[i]))
				break;

		if (i != N_IDS)
			centrino_cpu[policy->cpu] = &cpu_ids[i];

		if (!centrino_cpu[policy->cpu]) {
			dprintk(KERN_INFO PFX "found unsupported CPU with "
			"Enhanced SpeedStep: send /proc/cpuinfo to "
			MAINTAINER "\n");
			return -ENODEV;
		}

		if (centrino_cpu_init_table(policy)) {
			return -ENODEV;
		}
	}

	/* Check to see if Enhanced SpeedStep is enabled, and try to
	   enable it if not. */
	rdmsr(MSR_IA32_MISC_ENABLE, l, h);

	if (!(l & (1<<16))) {
		l |= (1<<16);
		dprintk("trying to enable Enhanced SpeedStep (%x)\n", l);
		wrmsr(MSR_IA32_MISC_ENABLE, l, h);

		/* check to see if it stuck */
		rdmsr(MSR_IA32_MISC_ENABLE, l, h);
		if (!(l & (1<<16))) {
			printk(KERN_INFO PFX "couldn't enable Enhanced SpeedStep\n");
			return -ENODEV;
		}
	}

	freq = get_cur_freq(policy->cpu);

	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
	policy->cpuinfo.transition_latency = 10000; /* 10uS transition latency */
	policy->cur = freq;

	dprintk("centrino_cpu_init: cur=%dkHz\n", policy->cur);

	ret = cpufreq_frequency_table_cpuinfo(policy, centrino_model[policy->cpu]->op_points);
	if (ret)
		return (ret);

	cpufreq_frequency_table_get_attr(centrino_model[policy->cpu]->op_points, policy->cpu);

	return 0;
}

static int centrino_cpu_exit(struct cpufreq_policy *policy)
{
	unsigned int cpu = policy->cpu;

	if (!centrino_model[cpu])
		return -ENODEV;

	cpufreq_frequency_table_put_attr(cpu);

#ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI
	if (!centrino_model[cpu]->model_name) {
		dprintk("unregistering and freeing ACPI data\n");
		acpi_processor_unregister_performance(&p, cpu);
		kfree(centrino_model[cpu]->op_points);
		kfree(centrino_model[cpu]);
	}
#endif

	centrino_model[cpu] = NULL;

	return 0;
}

/**
 * centrino_verify - verifies a new CPUFreq policy
 * @policy: new policy
 *
 * Limit must be within this model's frequency range at least one
 * border included.
 */
static int centrino_verify (struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, centrino_model[policy->cpu]->op_points);
}

/**
 * centrino_setpolicy - set a new CPUFreq policy
 * @policy: new policy
 * @target_freq: the target frequency
 * @relation: how that frequency relates to achieved frequency (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
 *
 * Sets a new CPUFreq policy.
 */
static int centrino_target (struct cpufreq_policy *policy,
			    unsigned int target_freq,
			    unsigned int relation)
{
	unsigned int    newstate = 0;
	unsigned int	msr, oldmsr, h, cpu = policy->cpu;
	struct cpufreq_freqs	freqs;
	cpumask_t		saved_mask;
	int			retval;

	if (centrino_model[cpu] == NULL)
		return -ENODEV;

	/*
	 * Support for SMP systems.
	 * Make sure we are running on the CPU that wants to change frequency
	 */
	saved_mask = current->cpus_allowed;
	set_cpus_allowed(current, policy->cpus);
	if (!cpu_isset(smp_processor_id(), policy->cpus)) {
		dprintk("couldn't limit to CPUs in this domain\n");
		return(-EAGAIN);
	}

	if (cpufreq_frequency_table_target(policy, centrino_model[cpu]->op_points, target_freq,
					   relation, &newstate)) {
		retval = -EINVAL;
		goto migrate_end;
	}

	msr = centrino_model[cpu]->op_points[newstate].index;
	rdmsr(MSR_IA32_PERF_CTL, oldmsr, h);

	if (msr == (oldmsr & 0xffff)) {
		retval = 0;
		dprintk("no change needed - msr was and needs to be %x\n", oldmsr);
		goto migrate_end;
	}

	freqs.cpu = cpu;
	freqs.old = extract_clock(oldmsr, cpu, 0);
	freqs.new = extract_clock(msr, cpu, 0);

	dprintk("target=%dkHz old=%d new=%d msr=%04x\n",
		target_freq, freqs.old, freqs.new, msr);

	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

	/* all but 16 LSB are "reserved", so treat them with
	   care */
	oldmsr &= ~0xffff;
	msr &= 0xffff;
	oldmsr |= msr;

	wrmsr(MSR_IA32_PERF_CTL, oldmsr, h);

	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

	retval = 0;
migrate_end:
	set_cpus_allowed(current, saved_mask);
	return (retval);
}

static struct freq_attr* centrino_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver centrino_driver = {
	.name		= "centrino", /* should be speedstep-centrino,
					 but there's a 16 char limit */
	.init		= centrino_cpu_init,
	.exit		= centrino_cpu_exit,
	.verify		= centrino_verify,
	.target		= centrino_target,
	.get		= get_cur_freq,
	.attr           = centrino_attr,
	.owner		= THIS_MODULE,
};


/**
 * centrino_init - initializes the Enhanced SpeedStep CPUFreq driver
 *
 * Initializes the Enhanced SpeedStep support. Returns -ENODEV on
 * unsupported devices, -ENOENT if there's no voltage table for this
 * particular CPU model, -EINVAL on problems during initiatization,
 * and zero on success.
 *
 * This is quite picky.  Not only does the CPU have to advertise the
 * "est" flag in the cpuid capability flags, we look for a specific
 * CPU model and stepping, and we need to have the exact model name in
 * our voltage tables.  That is, be paranoid about not releasing
 * someone's valuable magic smoke.
 */
static int __init centrino_init(void)
{
	struct cpuinfo_x86 *cpu = cpu_data;

	if (!cpu_has(cpu, X86_FEATURE_EST))
		return -ENODEV;

	return cpufreq_register_driver(&centrino_driver);
}

static void __exit centrino_exit(void)
{
	cpufreq_unregister_driver(&centrino_driver);
}

MODULE_AUTHOR ("Jeremy Fitzhardinge <[e-mail]>");
MODULE_DESCRIPTION ("Enhanced SpeedStep driver for Intel Pentium M processors.");
MODULE_LICENSE ("GPL");

late_initcall(centrino_init);
module_exit(centrino_exit);