path: root/drivers/cpufreq/powernow-k8.c

/*
 *   (c) 2003-2012 Advanced Micro Devices, Inc.
 *  Your use of this code is subject to the terms and conditions of the
 *  GNU general public license version 2. See "COPYING" or
 *  http://www.gnu.org/licenses/gpl.html
 *
 *  Maintainer:
 *  Andreas Herrmann <herrmann.der.user@googlemail.com>
 *
 *  Based on the powernow-k7.c module written by Dave Jones.
 *  (C) 2003 Dave Jones on behalf of SuSE Labs
 *  (C) 2004 Dominik Brodowski <linux@brodo.de>
 *  (C) 2004 Pavel Machek <pavel@ucw.cz>
 *  Licensed under the terms of the GNU GPL License version 2.
 *  Based upon datasheets & sample CPUs kindly provided by AMD.
 *
 *  Valuable input gratefully received from Dave Jones, Pavel Machek,
 *  Dominik Brodowski, Jacob Shin, and others.
 *  Originally developed by Paul Devriendt.
 *
 *  Processor information obtained from Chapter 9 (Power and Thermal
 *  Management) of the "BIOS and Kernel Developer's Guide (BKDG) for
 *  the AMD Athlon 64 and AMD Opteron Processors" and section "2.x
 *  Power Management" in BKDGs for newer AMD CPU families.
 *
 *  Tables for specific CPUs can be inferred from AMD's processor
 *  power and thermal data sheets, (e.g. 30417.pdf, 30430.pdf, 43375.pdf)
 */

#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/cpumask.h>
#include <linux/io.h>
#include <linux/delay.h>

#include <asm/msr.h>
#include <asm/cpu_device_id.h>

#include <linux/acpi.h>
#include <linux/mutex.h>
#include <acpi/processor.h>

#define PFX "powernow-k8: "
#define VERSION "version 2.20.00"
#include "powernow-k8.h"

/* serialize freq changes  */
static DEFINE_MUTEX(fidvid_mutex);

static DEFINE_PER_CPU(struct powernow_k8_data *, powernow_data);

static struct cpufreq_driver cpufreq_amd64_driver;

#ifndef CONFIG_SMP
static inline const struct cpumask *cpu_core_mask(int cpu)
{
	return cpumask_of(0);
}
#endif

/* Return a frequency in MHz, given an input fid */
static u32 find_freq_from_fid(u32 fid)
{
	return 800 + (fid * 100);
}

/* Return a frequency in KHz, given an input fid */
static u32 find_khz_freq_from_fid(u32 fid)
{
	return 1000 * find_freq_from_fid(fid);
}

/* Return the vco fid for an input fid
 *
 * Each "low" fid has corresponding "high" fid, and you can get to "low" fids
 * only from corresponding high fids. This returns "high" fid corresponding to
 * "low" one.
 */
static u32 convert_fid_to_vco_fid(u32 fid)
{
	if (fid < HI_FID_TABLE_BOTTOM)
		return 8 + (2 * fid);
	else
		return fid;
}

/*
 * Return 1 if the pending bit is set. Unless we just instructed the processor
 * to transition to a new state, seeing this bit set is really bad news.
 */
static int pending_bit_stuck(void)
{
	u32 lo, hi;

	rdmsr(MSR_FIDVID_STATUS, lo, hi);
	return lo & MSR_S_LO_CHANGE_PENDING ? 1 : 0;
}

/*
 * Update the global current fid / vid values from the status msr.
 * Returns 1 on error.
 */
static int query_current_values_with_pending_wait(struct powernow_k8_data *data)
{
	u32 lo, hi;
	u32 i = 0;

	do {
		if (i++ > 10000) {
			pr_debug("detected change pending stuck