/*
* This file was based upon code in Powertweak Linux (http://powertweak.sf.net)
* (C) 2000-2003 Dave Jones, Arjan van de Ven, Janne P�k�� Dominik Brodowski.
*
* Licensed under the terms of the GNU GPL License version 2.
*
* BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
*/
#include <linuxcomp.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <asm/msr.h>
#include <asm/timex.h>
#include <asm/io.h>
extern struct cpuinfo_x86 new_cpu_data
;
extern unsigned long cpu_khz
;
#define POWERNOW_IOPORT 0xfff0 /* it doesn't matter where, as long
as it is unused
*/
static unsigned int busfreq
; /* FSB, in 10 kHz */
static unsigned int max_multiplier
;
/* Clock ratio multiplied by 10 - see table 27 in AMD#23446 */
static struct cpufreq_frequency_table clock_ratio
[] = {
{45, /* 000 -> 4.5x */ 0},
{50, /* 001 -> 5.0x */ 0},
{40, /* 010 -> 4.0x */ 0},
{55, /* 011 -> 5.5x */ 0},
{20, /* 100 -> 2.0x */ 0},
{30, /* 101 -> 3.0x */ 0},
{60, /* 110 -> 6.0x */ 0},
{35, /* 111 -> 3.5x */ 0},
{0, CPUFREQ_TABLE_END
}
};
/**
* powernow_k6_get_cpu_multiplier - returns the current FSB multiplier
*
* Returns the current setting of the frequency multiplier. Core clock
* speed is frequency of the Front-Side Bus multiplied with this value.
*/
static int powernow_k6_get_cpu_multiplier
(void)
{
u64 invalue
= 0;
u32 msrval
;
msrval
= POWERNOW_IOPORT
+ 0x1;
wrmsr
(MSR_K6_EPMR
, msrval
, 0); /* enable the PowerNow port */
invalue
=inl
(POWERNOW_IOPORT
+ 0x8);
msrval
= POWERNOW_IOPORT
+ 0x0;
wrmsr
(MSR_K6_EPMR
, msrval
, 0); /* disable it again */
return clock_ratio
[(invalue
>> 5)&7].
index;
}
/**
* powernow_k6_set_state - set the PowerNow! multiplier
* @best_i: clock_ratio[best_i] is the target multiplier
*
* Tries to change the PowerNow! multiplier
*/
static void powernow_k6_set_state
(unsigned int best_i
)
{
unsigned long outvalue
=0, invalue
=0;
unsigned long msrval
;
struct cpufreq_freqs freqs
;
if (clock_ratio
[best_i
].
index > max_multiplier
) {
printk
(KERN_ERR
"cpufreq: invalid target frequency\n");
return;
}
freqs.
old = busfreq
* powernow_k6_get_cpu_multiplier
();
freqs.
new = busfreq
* clock_ratio
[best_i
].
index;
freqs.
cpu = 0; // powernow-k6.c is UP only driver
cpufreq_notify_transition
(&freqs
, CPUFREQ_PRECHANGE
);
/* we now need to transform best_i to the BVC format, see AMD#23446 */
outvalue
= (1<<12) | (1<<10) | (1<<9) | (best_i
<<5);
msrval
= POWERNOW_IOPORT
+ 0x1;
wrmsr
(MSR_K6_EPMR
, msrval
, 0); /* enable the PowerNow port */
invalue
=inl
(POWERNOW_IOPORT
+ 0x8);
invalue
= invalue
& 0xf;
outvalue
= outvalue
| invalue
;
outl
(outvalue
,(POWERNOW_IOPORT
+ 0x8));
msrval
= POWERNOW_IOPORT
+ 0x0;
wrmsr
(MSR_K6_EPMR
, msrval
, 0); /* disable it again */
cpufreq_notify_transition
(&freqs
, CPUFREQ_POSTCHANGE
);
return;
}
/**
* powernow_k6_verify - verifies a new CPUfreq policy
* @policy: new policy
*
* Policy must be within lowest and highest possible CPU Frequency,
* and at least one possible state must be within min and max.
*/
static int powernow_k6_verify
(struct cpufreq_policy
*policy
)
{
return cpufreq_frequency_table_verify
(policy
, &clock_ratio
[0]);
}
/**
* powernow_k6_setpolicy - sets a new CPUFreq policy
* @policy - new policy
*
* sets a new CPUFreq policy
*/
static int powernow_k6_target
(struct cpufreq_policy
*policy
,
unsigned int target_freq
,
unsigned int relation
)
{
unsigned int newstate
= 0;
if (cpufreq_frequency_table_target
(policy
, &clock_ratio
[0], target_freq
, relation
, &newstate
))
return -EINVAL
;
powernow_k6_set_state
(newstate
);
return 0;
}
static int powernow_k6_cpu_init
(struct cpufreq_policy
*policy
)
{
unsigned int i
;
if (policy
->cpu
!= 0)
return -ENODEV
;
/* get frequencies */
max_multiplier
= powernow_k6_get_cpu_multiplier
();
busfreq
= cpu_khz
/ max_multiplier
;
/* table init */
for (i
=0; (clock_ratio
[i
].
frequency != CPUFREQ_TABLE_END
); i
++) {
if (clock_ratio
[i
].
index > max_multiplier
)
clock_ratio
[i
].
frequency = CPUFREQ_ENTRY_INVALID
;
else
clock_ratio
[i
].
frequency = busfreq
* clock_ratio
[i
].
index;
}
/* cpuinfo and default policy values */
policy
->governor
= 0; //!!!CPUFREQ_DEFAULT_GOVERNOR;
policy
->cpuinfo.
transition_latency = CPUFREQ_ETERNAL
;
policy
->cur
= busfreq
* max_multiplier
;
return cpufreq_frequency_table_cpuinfo
(policy
, &clock_ratio
[0]);
}
static int powernow_k6_cpu_exit
(struct cpufreq_policy
*policy
)
{
unsigned int i
;
for (i
=0; i
<8; i
++) {
if (i
==max_multiplier
)
powernow_k6_set_state
(i
);
}
return 0;
}
static struct cpufreq_driver powernow_k6_driver
= {
.
verify = powernow_k6_verify
,
.
target = powernow_k6_target
,
.
init = powernow_k6_cpu_init
,
.
exit = powernow_k6_cpu_exit
,
.
name = "powernow-k6",
.
owner = THIS_MODULE
,
};
/**
* powernow_k6_init - initializes the k6 PowerNow! CPUFreq driver
*
* Initializes the K6 PowerNow! support. Returns -ENODEV on unsupported
* devices, -EINVAL or -ENOMEM on problems during initiatization, and zero
* on success.
*/
/*static*/ int __init powernow_k6_init
(void)
{
struct cpuinfo_x86
*c
= &new_cpu_data
;
if ((c
->x86_vendor
!= X86_VENDOR_AMD
) || (c
->x86
!= 5) ||
((c
->x86_model
!= 12) && (c
->x86_model
!= 13)))
return -ENODEV
;
if (!request_region
(POWERNOW_IOPORT
, 16, "PowerNow!")) {
printk
("cpufreq: PowerNow IOPORT region already used.\n");
return -EIO
;
}
if (cpufreq_register_driver
(&powernow_k6_driver
)) {
release_region
(POWERNOW_IOPORT
, 16);
return -EINVAL
;
}
return 0;
}
/**
* powernow_k6_exit - unregisters AMD K6-2+/3+ PowerNow! support
*
* Unregisters AMD K6-2+ / K6-3+ PowerNow! support.
*/
/*static*/ void __exit powernow_k6_exit
(void)
{
cpufreq_unregister_driver
(&powernow_k6_driver
);
release_region
(POWERNOW_IOPORT
, 16);
}
MODULE_AUTHOR
("Arjan van de Ven <arjanv@redhat.com>, Dave Jones <davej@codemonkey.org.uk>, Dominik Brodowski <linux@brodo.de>");
MODULE_DESCRIPTION
("PowerNow! driver for AMD K6-2+ / K6-3+ processors.");
MODULE_LICENSE
("GPL");
module_init
(powernow_k6_init
);
module_exit
(powernow_k6_exit
);