processor_perflib.c

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/*
 * processor_perflib.c - ACPI Processor P-States Library ($Revision: 71 $)
 *
 *  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/cpufreq.h>

#ifdef CONFIG_X86_ACPI_CPUFREQ_PROC_INTF
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/mutex.h>

#include <asm/uaccess.h>
#endif

#include <acpi/acpi_bus.h>
#include <acpi/processor.h>

#define ACPI_PROCESSOR_COMPONENT	0x01000000
#define ACPI_PROCESSOR_CLASS		"processor"
#define ACPI_PROCESSOR_FILE_PERFORMANCE	"performance"
#define _COMPONENT		ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_perflib");

static DEFINE_MUTEX(performance_mutex);

/*
 * _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.
 */

#define PPC_REGISTERED   1
#define PPC_IN_USE       2

static int acpi_processor_ppc_status = 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;

	mutex_lock(&performance_mutex);

	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 >= pr->performance->state_count)
		goto out;

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

      out:
	mutex_unlock(&performance_mutex);

	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;


	if (!pr)
		return -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 (status != AE_NOT_FOUND)
		acpi_processor_ppc_status |= PPC_IN_USE;

	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PPC"));
		return -ENODEV;
	}

	pr->performance_platform_limit = (int)ppc;

	return 0;
}

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);
}

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

void acpi_processor_ppc_exit(void)
{
	if (acpi_processor_ppc_status & PPC_REGISTERED)
		cpufreq_unregister_notifier(&acpi_ppc_notifier_block,
					    CPUFREQ_POLICY_NOTIFIER);

	acpi_processor_ppc_status &= ~PPC_REGISTERED;
}

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 };


	status = acpi_evaluate_object(pr->handle, "_PCT", NULL, &buffer);
	if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PCT"));
		return -ENODEV;
	}

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

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

      end:
	kfree(buffer.pointer);

	return 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;


	status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
	if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PSS"));
		return -ENODEV;
	}

	pss = buffer.pointer;
	if (!pss || (pss->type != ACPI_TYPE_PACKAGE)) {
		printk(KERN_ERR PREFIX "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);
		state.pointer = px;

		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));

		status = acpi_extract_package(&(pss->package.elements[i]),
					      &format, &state);
		if (ACPI_FAILURE(status)) {
			ACPI_EXCEPTION((AE_INFO, status, "Invalid _PSS data"));
			result = -EFAULT;
			kfree(pr->performance->states);
			goto end;
		}

		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]\n",
				  i,
				  (u32) px->core_frequency,
				  (u32) px->power,
				  (u32) px->transition_latency,
				  (u32) px->bus_master_latency,
				  (u32) px->control, (u32) px->status));

		if (!px->core_frequency) {
			printk(KERN_ERR PREFIX
				    "Invalid _PSS data: freq is zero\n");
			result = -EFAULT;
			kfree(pr->performance->states);
			goto end;
		}
	}

      end:
	kfree(buffer.pointer);

	return result;
}

static int acpi_processor_get_performance_info(struct acpi_processor *pr)
{
	int result = 0;
	acpi_status status = AE_OK;
	acpi_handle handle = NULL;


	if (!pr || !pr->performance || !pr->handle)
		return -EINVAL;

	status = acpi_get_handle(pr->handle, "_PCT", &handle);
	if (ACPI_FAILURE(status)) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "ACPI-based processor performance control unavailable\n"));
		return -ENODEV;
	}

	result = acpi_processor_get_performance_control(pr);
	if (result)
		return result;

	result = acpi_processor_get_performance_states(pr);
	if (result)
		return result;

	return 0;
}

int acpi_processor_notify_smm(struct module *calling_module)
{
	acpi_status status;
	static int is_done = 0;


	if (!(acpi_processor_ppc_status & PPC_REGISTERED))
		return -EBUSY;

	if (!try_module_get(calling_module))
		return -EINVAL;

	/* is_done is set to negative if an error occured,
	 * and to postitive if _no_ error occured, but SMM
	 * was already notified. This avoids double notification
	 * which might lead to unexpected results...
	 */
	if (is_done > 0) {
		module_put(calling_module);
		return 0;
	} else if (is_done < 0) {
		module_put(calling_module);
		return is_done;
	}

	is_done = -EIO;

	/* Can't write pstate_control to smi_command if either value is zero */
	if ((!acpi_gbl_FADT.smi_command) || (!acpi_gbl_FADT.pstate_control)) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No SMI port or pstate_control\n"));
		module_put(calling_module);
		return 0;
	}

	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
			  "Writing pstate_control [0x%x] to smi_command [0x%x]\n",
			  acpi_gbl_FADT.pstate_control, acpi_gbl_FADT.smi_command));

	status = acpi_os_write_port(acpi_gbl_FADT.smi_command,
				    (u32) acpi_gbl_FADT.pstate_control, 8);
	if (ACPI_FAILURE(status)) {
		ACPI_EXCEPTION((AE_INFO, status,
				"Failed to write pstate_control [0x%x] to "
				"smi_command [0x%x]", acpi_gbl_FADT.pstate_control,
				acpi_gbl_FADT.smi_command));
		module_put(calling_module);
		return status;
	}

	/* Success. If there's no _PPC, we need to fear nothing, so
	 * we can allow the cpufreq driver to be rmmod'ed. */
	is_done = 1;

	if (!(acpi_processor_ppc_status & PPC_IN_USE))
		module_put(calling_module);

	return 0;
}

EXPORT_SYMBOL(acpi_processor_notify_smm);