processor_throttling.c

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/*
 * processor_throttling.c - Throttling submodule of the ACPI processor driver
 *
 *  Copyright (C) 2001, 2002 Andy Grover <[e-mail]>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[e-mail]>
 *  Copyright (C) 2004       Dominik Brodowski <[e-mail]>
 *  Copyright (C) 2004  Anil S Keshavamurthy <[e-mail]>
 *  			- 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