acpi-cpufreq.c

linux 内核源代码

#else
	online_policy_cpus = policy->cpus;
#endif

	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);
			return 0;
		}
	}

	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:
		return -ENODEV;
	}

	cpus_clear(cmd.mask);

	if (policy->shared_type != CPUFREQ_SHARED_TYPE_ANY)
		cmd.mask = online_policy_cpus;
	else
		cpu_set(policy->cpu, cmd.mask);

	freqs.old = perf->states[perf->state].core_frequency * 1000;
	freqs.new = data->freq_table[next_state].frequency;
	for_each_cpu_mask(i, cmd.mask) {
		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);
			return -EAGAIN;
		}
	}

	for_each_cpu_mask(i, cmd.mask) {
		freqs.cpu = i;
		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	}
	perf->state = next_perf_state;

	return result;
}

static int acpi_cpufreq_verify(struct cpufreq_policy *policy)
{
	struct acpi_cpufreq_data *data = drv_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;
	}
}

/*
 * 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)
{
	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;
	}

	/* 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"),
		},
	},
	{ }
};
#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;

	dprintk("acpi_cpufreq_cpu_init\n");

	data = kzalloc(sizeof(struct acpi_cpufreq_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->acpi_data = percpu_ptr(acpi_perf_data, cpu);
	drv_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) {
		policy->cpus = perf->shared_cpu_map;
	}

#ifdef CONFIG_SMP
	dmi_check_system(sw_any_bug_dmi_table);
	if (bios_with_sw_any_bug && cpus_weight(policy->cpus) == 1) {
		policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
		policy->cpus = per_cpu(cpu_core_map, 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;
	}

	data->max_freq = perf->states[0].core_frequency * 1000;
	/* 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;

	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 (c->x86_vendor == X86_VENDOR_INTEL && c->cpuid_level >= 6) {
		unsigned int ecx;
		ecx = cpuid_ecx(6);
		if (ecx & CPUID_6_ECX_APERFMPERF_CAPABILITY)
			acpi_cpufreq_driver.getavg = 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);
	drv_data[cpu] = NULL;

	return result;
}

static int acpi_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
	struct acpi_cpufreq_data *data = drv_data[policy->cpu];

	dprintk("acpi_cpufreq_cpu_exit\n");

	if (data) {
		cpufreq_frequency_table_put_attr(policy->cpu);
		drv_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 = drv_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,
	.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;

	dprintk("acpi_cpufreq_init\n");

	ret = acpi_cpufreq_early_init();
	if (ret)
		return ret;

	return cpufreq_register_driver(&acpi_cpufreq_driver);
}

static void __exit acpi_cpufreq_exit(void)
{
	dprintk("acpi_cpufreq_exit\n");

	cpufreq_unregister_driver(&acpi_cpufreq_driver);

	free_percpu(acpi_perf_data);

	return;
}

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");