processor.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,497 行 · 第 1/5 页

end:
	/*
	 * New Cx State?
	 * -------------
	 * If we're going to start using a new Cx state we must clean up
	 * from the previous and prepare to use the new.
	 */
	if (next_state != pr->power.state)
		acpi_processor_power_activate(pr, next_state);

	return;
}


static int
acpi_processor_set_power_policy (
	struct acpi_processor	*pr)
{
	ACPI_FUNCTION_TRACE("acpi_processor_set_power_policy");

	/*
	 * This function sets the default Cx state policy (OS idle handler).
	 * Our scheme is to promote quickly to C2 but more conservatively
	 * to C3.  We're favoring C2  for its characteristics of low latency
	 * (quick response), good power savings, and ability to allow bus
	 * mastering activity.  Note that the Cx state policy is completely
	 * customizable and can be altered dynamically.
	 */

	if (!pr)
		return_VALUE(-EINVAL);

	/*
	 * C0/C1
	 * -----
	 */
	pr->power.state = ACPI_STATE_C1;
	pr->power.default_state = ACPI_STATE_C1;

	/*
	 * C1/C2
	 * -----
	 * Set the default C1 promotion and C2 demotion policies, where we
	 * promote from C1 to C2 after several (10) successive C1 transitions,
	 * as we cannot (currently) measure the time spent in C1. Demote from
	 * C2 to C1 anytime we experience a 'short' (time spent in C2 is less
	 * than the C2 transtion latency).  Note the simplifying assumption 
	 * that the 'cost' of a transition is amortized when we sleep for at
	 * least as long as the transition's latency (thus the total transition
	 * time is two times the latency).
	 *
	 * TBD: Measure C1 sleep times by instrumenting the core IRQ handler.
	 * TBD: Demote to default C-State after long periods of activity.
	 * TBD: Investigate policy's use of CPU utilization -vs- sleep duration.
	 */
	if (pr->power.states[ACPI_STATE_C2].valid) {
		pr->power.states[ACPI_STATE_C1].promotion.threshold.count = 10;
		pr->power.states[ACPI_STATE_C1].promotion.threshold.ticks =
			pr->power.states[ACPI_STATE_C2].latency_ticks;
		pr->power.states[ACPI_STATE_C1].promotion.state = ACPI_STATE_C2;

		pr->power.states[ACPI_STATE_C2].demotion.threshold.count = 1;
		pr->power.states[ACPI_STATE_C2].demotion.threshold.ticks =
			pr->power.states[ACPI_STATE_C2].latency_ticks;
		pr->power.states[ACPI_STATE_C2].demotion.state = ACPI_STATE_C1;
	}

	/*
	 * C2/C3
	 * -----
	 * Set default C2 promotion and C3 demotion policies, where we promote
	 * from C2 to C3 after several (4) cycles of no bus mastering activity
	 * while maintaining sleep time criteria.  Demote immediately on a
	 * short or whenever bus mastering activity occurs.
	 */
	if ((pr->power.states[ACPI_STATE_C2].valid) &&
		(pr->power.states[ACPI_STATE_C3].valid)) {
		pr->power.states[ACPI_STATE_C2].promotion.threshold.count = 4;
		pr->power.states[ACPI_STATE_C2].promotion.threshold.ticks =
			pr->power.states[ACPI_STATE_C3].latency_ticks;
		pr->power.states[ACPI_STATE_C2].promotion.threshold.bm = 0x0F;
		pr->power.states[ACPI_STATE_C2].promotion.state = ACPI_STATE_C3;

		pr->power.states[ACPI_STATE_C3].demotion.threshold.count = 1;
		pr->power.states[ACPI_STATE_C3].demotion.threshold.ticks =
			pr->power.states[ACPI_STATE_C3].latency_ticks;
		pr->power.states[ACPI_STATE_C3].demotion.threshold.bm = 0x0F;
		pr->power.states[ACPI_STATE_C3].demotion.state = ACPI_STATE_C2;
	}

	return_VALUE(0);
}


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

	ACPI_FUNCTION_TRACE("acpi_processor_get_power_info");

	if (!pr)
		return_VALUE(-EINVAL);

	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
		"lvl2[0x%08x] lvl3[0x%08x]\n",
		pr->power.states[ACPI_STATE_C2].address,
		pr->power.states[ACPI_STATE_C3].address));

	/* TBD: Support ACPI 2.0 objects */

	/*
	 * C0
	 * --
	 * This state exists only as filler in our array.
	 */
	pr->power.states[ACPI_STATE_C0].valid = 1;

	/*
	 * C1
	 * --
	 * ACPI requires C1 support for all processors.
	 *
	 * TBD: What about PROC_C1?
	 */
	pr->power.states[ACPI_STATE_C1].valid = 1;

	/*
	 * C2
	 * --
	 * We're (currently) only supporting C2 on UP systems.
	 *
	 * TBD: Support for C2 on MP (P_LVL2_UP).
	 */
	if (pr->power.states[ACPI_STATE_C2].address) {

		pr->power.states[ACPI_STATE_C2].latency = acpi_fadt.plvl2_lat;

		/*
		 * C2 latency must be less than or equal to 100 microseconds.
		 */
		if (acpi_fadt.plvl2_lat > ACPI_PROCESSOR_MAX_C2_LATENCY)
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				"C2 latency too large [%d]\n",
				acpi_fadt.plvl2_lat));
		/*
		 * Only support C2 on UP systems (see TBD above).
		 */
		else if (errata.smp)
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				"C2 not supported in SMP mode\n"));
		/*
		 * Otherwise we've met all of our C2 requirements.
		 * Normalize the C2 latency to expidite policy.
		 */
		else {
			pr->power.states[ACPI_STATE_C2].valid = 1;
			pr->power.states[ACPI_STATE_C2].latency_ticks = 
				US_TO_PM_TIMER_TICKS(acpi_fadt.plvl2_lat);
		}
	}

	/*
	 * C3
	 * --
	 * TBD: Investigate use of WBINVD on UP/SMP system in absence of
	 *	bm_control.
	 */
	if (pr->power.states[ACPI_STATE_C3].address) {

		pr->power.states[ACPI_STATE_C3].latency = acpi_fadt.plvl3_lat;

		/*
		 * C3 latency must be less than or equal to 1000 microseconds.
		 */
		if (acpi_fadt.plvl3_lat > ACPI_PROCESSOR_MAX_C3_LATENCY)
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				"C3 latency too large [%d]\n", 
				acpi_fadt.plvl3_lat));
		/*
		 * Only support C3 when bus mastering arbitration control
		 * is present (able to disable bus mastering to maintain
		 * cache coherency while in C3).
		 */
		else if (!pr->flags.bm_control)
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				"C3 support requires bus mastering control\n"));
		/*
		 * Only support C3 on UP systems, as bm_control is only viable
		 * on a UP system and flushing caches (e.g. WBINVD) is simply 
		 * too costly (at this time).
		 */
		else if (errata.smp)
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				"C3 not supported in SMP mode\n"));
		/*
		 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast) 
		 * DMA transfers are used by any ISA device to avoid livelock.
		 * Note that we could disable Type-F DMA (as recommended by
		 * the erratum), but this is known to disrupt certain ISA 
		 * devices thus we take the conservative approach.
		 */
		else if (errata.piix4.fdma) {
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				"C3 not supported on PIIX4 with Type-F DMA\n"));
		}
		/*
		 * Otherwise we've met all of our C3 requirements.  
		 * Normalize the C2 latency to expidite policy.  Enable
		 * checking of bus mastering status (bm_check) so we can 
		 * use this in our C3 policy.
		 */
		else {
			pr->power.states[ACPI_STATE_C3].valid = 1;
			pr->power.states[ACPI_STATE_C3].latency_ticks = 
				US_TO_PM_TIMER_TICKS(acpi_fadt.plvl3_lat);
			pr->flags.bm_check = 1;
		}
	}

	/*
	 * Set Default Policy
	 * ------------------
	 * Now that we know which state are supported, set the default
	 * policy.  Note that this policy can be changed dynamically
	 * (e.g. encourage deeper sleeps to conserve battery life when
	 * not on AC).
	 */
	result = acpi_processor_set_power_policy(pr);
	if (result)
		return_VALUE(result);

	/*
	 * If this processor supports C2 or C3 we denote it as being 'power
	 * manageable'.  Note that there's really no policy involved for
	 * when only C1 is supported.
	 */
	if (pr->power.states[ACPI_STATE_C2].valid 
		|| pr->power.states[ACPI_STATE_C3].valid)
		pr->flags.power = 1;

	return_VALUE(0);
}


/* --------------------------------------------------------------------------
                              Performance Management
   -------------------------------------------------------------------------- */
#ifdef CONFIG_CPU_FREQ

static DECLARE_MUTEX(performance_sem);

/*
 * _PPC support is implemented as a CPUfreq policy notifier: 
 * This means each time a CPUfreq driver registered also with
 * the ACPI core is asked to change the speed policy, the maximum
 * value is adjusted so that it is within the platform limit.
 * 
 * Also, when a new platform limit value is detected, the CPUfreq
 * policy is adjusted accordingly.
 */

static int acpi_processor_ppc_is_init = 0;

static int acpi_processor_ppc_notifier(struct notifier_block *nb, 
	unsigned long event,
	void *data)
{
	struct cpufreq_policy *policy = data;
	struct acpi_processor *pr;
	unsigned int ppc = 0;

	down(&performance_sem);

	if (event != CPUFREQ_INCOMPATIBLE)
		goto out;

	pr = processors[policy->cpu];
	if (!pr || !pr->performance)
		goto out;

	ppc = (unsigned int) pr->performance_platform_limit;
	if (!ppc)
		goto out;

	if (ppc > pr->performance->state_count)
		goto out;

	cpufreq_verify_within_limits(policy, 0, 
		pr->performance->states[ppc].core_frequency * 1000);

 out:
	up(&performance_sem);

	return 0;
}


static struct notifier_block acpi_ppc_notifier_block = {
	.notifier_call = acpi_processor_ppc_notifier,
};


static int
acpi_processor_get_platform_limit (
	struct acpi_processor*	pr)
{
	acpi_status		status = 0;
	unsigned long		ppc = 0;

	ACPI_FUNCTION_TRACE("acpi_processor_get_platform_limit");

	if (!pr)
		return_VALUE(-EINVAL);

	/*
	 * _PPC indicates the maximum state currently supported by the platform
	 * (e.g. 0 = states 0..n; 1 = states 1..n; etc.
	 */
	status = acpi_evaluate_integer(pr->handle, "_PPC", NULL, &ppc);
	if(ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PPC\n"));
		return_VALUE(-ENODEV);
	}

	pr->performance_platform_limit = (int) ppc;
	
	return_VALUE(0);
}


static int acpi_processor_ppc_has_changed(
	struct acpi_processor *pr)
{
	int ret = acpi_processor_get_platform_limit(pr);
	if (ret < 0)
		return (ret);
	else
		return cpufreq_update_policy(pr->id);
}


static void acpi_processor_ppc_init(void) {
	if (!cpufreq_register_notifier(&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER))
		acpi_processor_ppc_is_init = 1;
	else
		printk(KERN_DEBUG "Warning: Processor Platform Limit not supported.\n");
}


static void acpi_processor_ppc_exit(void) {
	if (acpi_processor_ppc_is_init)
		cpufreq_unregister_notifier(&acpi_ppc_notifier_block, CPUFREQ_POLICY_NOTIFIER);

	acpi_processor_ppc_is_init = 0;
}

/*
 * when registering a cpufreq driver with this ACPI processor driver, the
 * _PCT and _PSS structures are read out and written into struct
 * acpi_processor_performance.
 */
static int acpi_processor_set_pdc (struct acpi_processor *pr)
{
	acpi_status             status = AE_OK;
	u32			arg0_buf[3];
	union acpi_object	arg0 = {ACPI_TYPE_BUFFER};
	struct acpi_object_list no_object = {1, &arg0};
	struct acpi_object_list *pdc;

	ACPI_FUNCTION_TRACE("acpi_processor_set_pdc");
	
	arg0.buffer.length = 12;
	arg0.buffer.pointer = (u8 *) arg0_buf;
	arg0_buf[0] = ACPI_PDC_REVISION_ID;
	arg0_buf[1] = 0;
	arg0_buf[2] = 0;

	pdc = (pr->performance->pdc) ? pr->performance->pdc : &no_object;

	status = acpi_evaluate_object(pr->handle, "_PDC", pdc, NULL);

	if ((ACPI_FAILURE(status)) && (pr->performance->pdc))
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Error evaluating _PDC, using legacy perf. control...\n"));

	return_VALUE(status);
}


static int 
acpi_processor_get_performance_control (
	struct acpi_processor *pr)
{
	int			result = 0;
	acpi_status		status = 0;
	struct acpi_buffer	buffer = {ACPI_ALLOCATE_BUFFER, NULL};
	union acpi_object	*pct = NULL;
	union acpi_object	obj = {0};

	ACPI_FUNCTION_TRACE("acpi_processor_get_performance_control");

	status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
	if(ACPI_FAILURE(status)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PCT\n"));
		return_VALUE(-ENODEV);
	}

	pct = (union acpi_object *) buffer.pointer;
	if (!pct || (pct->type != ACPI_TYPE_PACKAGE) 
		|| (pct->package.count != 2)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _PCT data\n"));
		result = -EFAULT;
		goto end;
	}

	/*
	 * control_register
	 */

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

	if ((obj.type != ACPI_TYPE_BUFFER) 
		|| (obj.buffer.length < sizeof(struct acpi_pct_register)) 
		|| (obj.buffer.pointer == NULL)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 
			"Invalid _PCT data (control_register)\n"));
		result = -EFAULT;
		goto end;
	}
	memcpy(&pr->performance->control_register, obj.buffer.pointer, sizeof(struct acpi_pct_register));


	/*
	 * status_register
	 */

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

	if ((obj.type != ACPI_TYPE_BUFFER) 
		|| (obj.buffer.length < sizeof(struct acpi_pct_register)) 
		|| (obj.buffer.pointer == NULL)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, 
			"Invalid _PCT data (status_register)\n"));
		result = -EFAULT;
		goto end;
	}

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

end:
	acpi_os_free(buffer.pointer);

	return_VALUE(result);
}


static int 
acpi_processor_get_performance_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("NNNNNN"), "NNNNNN"};
	struct acpi_buffer	state = {0, NULL};
	union acpi_object 	*pss = NULL;
	int			i = 0;

	ACPI_FUNCTION_TRACE("acpi_processor_get_performance_states");

	status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
	if(ACPI_FAILURE(status)) {
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PSS\n"));
		return_VALUE(-ENODEV);
	}

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

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

	pr->performance->state_count = pss->package.count;
	pr->performance->states = kmalloc(sizeof(struct acpi_processor_px) * pss->package.count, GFP_KERNEL);
	if (!pr->performance->states) {
		result = -ENOMEM;
		goto end;
	}

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

		struct acpi_processor_px *px = &(pr->performance->states[i]);

		state.length = sizeof(struct acpi_processor_px);