/*
* AMD K7 Powernow driver.
* (C) 2003 Dave Jones <davej@codemonkey.org.uk> on behalf of SuSE Labs.
* (C) 2003 Dave Jones <davej@redhat.com>
*
* Licensed under the terms of the GNU GPL License version 2.
* Based upon datasheets & sample CPUs kindly provided by AMD.
*
* BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
*
* Errata 5: Processor may fail to execute a FID/VID change in presence of interrupt.
* - We cli/sti on stepping A0 CPUs around the FID/VID transition.
* Errata 15: Processors with half frequency multipliers may hang upon wakeup from disconnect.
* - We disable half multipliers if ACPI is used on A0 stepping CPUs.
*/
#include <linuxcomp.h>
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <asm/msr.h>
#include <asm/timex.h>
#include <asm/io.h>
#include <asm/system.h>
#include "powernow-k7.h"
//#define DEBUG
#ifdef DEBUG
#define dprintk(msg...) printk(msg)
#else
#define dprintk(msg...) do { } while(0)
#endif
#define PFX "powernow: "
extern struct cpuinfo_x86 new_cpu_data
;
struct psb_s
{
u8 signature
[10];
u8 tableversion
;
u8 flags
;
u16 settlingtime
;
u8 reserved1
;
u8 numpst
;
};
struct pst_s
{
u32 cpuid
;
u8 fsbspeed
;
u8 maxfid
;
u8 startvid
;
u8 numpstates
;
};
/* divide by 1000 to get VID. */
static int mobile_vid_table
[32] = {
2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
1075, 1050, 1024, 1000, 975, 950, 925, 0,
};
/* divide by 10 to get FID. */
static int fid_codes
[32] = {
110, 115, 120, 125, 50, 55, 60, 65,
70, 75, 80, 85, 90, 95, 100, 105,
30, 190, 40, 200, 130, 135, 140, 210,
150, 225, 160, 165, 170, 180, -1, -1,
};
static struct cpufreq_frequency_table
*powernow_table
;
static unsigned int can_scale_bus
;
static unsigned int can_scale_vid
;
static unsigned int minimum_speed
=-1;
static unsigned int maximum_speed
;
static unsigned int number_scales
;
static unsigned int fsb
;
static unsigned int latency
;
static char have_a0
;
static int check_powernow
(void)
{
struct cpuinfo_x86
*c
= &new_cpu_data
; /* Nino */
unsigned int maxei
, eax
, ebx
, ecx
, edx
;
if (c
->x86_vendor
!= X86_VENDOR_AMD
) {
dprintk
(KERN_INFO PFX
"AMD processor not detected.\n");
return 0;
}
if (c
->x86
!=6) {
dprintk
(KERN_INFO PFX
"This module only works with AMD K7 CPUs\n");
return 0;
}
printk
(KERN_INFO PFX
"AMD K7 CPU detected.\n");
if ((c
->x86_model
== 6) && (c
->x86_mask
== 0)) {
dprintk
(KERN_INFO PFX
"K7 660[A0] core detected, enabling errata workarounds\n");
have_a0
= 1;
}
/* Get maximum capabilities */
maxei
= cpuid_eax
(0x80000000);
if (maxei
< 0x80000007) { /* Any powernow info ? */
printk
(KERN_INFO PFX
"No powernow capabilities detected\n");
return 0;
}
cpuid
(0x80000007, &eax
, &ebx
, &ecx
, &edx
);
printk
(KERN_INFO PFX
"PowerNOW! Technology present. Can scale: ");
if (edx
& 1 << 1) {
printk
("frequency");
can_scale_bus
=1;
}
if ((edx
& (1 << 1 | 1 << 2)) == 0x6)
printk
(" and ");
if (edx
& 1 << 2) {
printk
("voltage");
can_scale_vid
=1;
}
if (!(edx
& (1 << 1 | 1 << 2))) {
printk
("nothing.\n");
return 0;
}
printk
(".\n");
return 1;
}
static int get_ranges
(unsigned char *pst
)
{
unsigned int j
, speed
;
u8 fid
, vid
;
powernow_table
= kmalloc
((sizeof(struct cpufreq_frequency_table
) * (number_scales
+ 1)), GFP_KERNEL
);
if (!powernow_table
)
return -ENOMEM
;
memset(powernow_table
, 0, (sizeof(struct cpufreq_frequency_table
) * (number_scales
+ 1)));
for (j
=0 ; j
< number_scales
; j
++) {
fid
= *pst
++;
powernow_table
[j
].
frequency = fsb
* fid_codes
[fid
] * 100;
powernow_table
[j
].
index = fid
; /* lower 8 bits */
speed
= fsb
* (fid_codes
[fid
]/10);
if ((fid_codes
[fid
] % 10)==5) {
speed
+= fsb
/2;
#if defined(CONFIG_ACPI_PROCESSOR) || defined(CONFIG_ACPI_PROCESSOR_MODULE)
if (have_a0
== 1)
powernow_table
[j
].
frequency = CPUFREQ_ENTRY_INVALID
;
#endif
}
dprintk
(KERN_INFO PFX
" FID: 0x%x (%d.%dx [%dMHz])\t", fid
,
fid_codes
[fid
] / 10, fid_codes
[fid
] % 10, speed
);
if (speed
< minimum_speed
)
minimum_speed
= speed
;
if (speed
> maximum_speed
)
maximum_speed
= speed
;
vid
= *pst
++;
powernow_table
[j
].
index |= (vid
<< 8); /* upper 8 bits */
dprintk
("VID: 0x%x (%d.%03dV)\n", vid
, mobile_vid_table
[vid
]/1000,
mobile_vid_table
[vid
]%1000);
}
dprintk
("\n");
powernow_table
[number_scales
].
frequency = CPUFREQ_TABLE_END
;
powernow_table
[number_scales
].
index = 0;
return 0;
}
static void change_FID
(int fid
)
{
union msr_fidvidctl fidvidctl
;
rdmsrl
(MSR_K7_FID_VID_CTL
, fidvidctl.
val);
if (fidvidctl.
bits.
FID != fid
) {
fidvidctl.
bits.
SGTC = latency
;
fidvidctl.
bits.
FID = fid
;
fidvidctl.
bits.
VIDC = 0;
fidvidctl.
bits.
FIDC = 1;
wrmsrl
(MSR_K7_FID_VID_CTL
, fidvidctl.
val);
}
}
static void change_VID
(int vid
)
{
union msr_fidvidctl fidvidctl
;
rdmsrl
(MSR_K7_FID_VID_CTL
, fidvidctl.
val);
if (fidvidctl.
bits.
VID != vid
) {
fidvidctl.
bits.
SGTC = latency
;
fidvidctl.
bits.
VID = vid
;
fidvidctl.
bits.
FIDC = 0;
fidvidctl.
bits.
VIDC = 1;
wrmsrl
(MSR_K7_FID_VID_CTL
, fidvidctl.
val);
}
}
static void change_speed
(unsigned int index
)
{
u8 fid
, vid
;
struct cpufreq_freqs freqs
;
union msr_fidvidstatus fidvidstatus
;
int cfid
;
/* fid are the lower 8 bits of the index we stored into
* the cpufreq frequency table in powernow_decode_bios,
* vid are the upper 8 bits.
*/
fid
= powernow_table
[index
].
index & 0xFF;
vid
= (powernow_table
[index
].
index & 0xFF00) >> 8;
freqs.
cpu = 0;
rdmsrl
(MSR_K7_FID_VID_STATUS
, fidvidstatus.
val);
cfid
= fidvidstatus.
bits.
CFID;
freqs.
old = fsb
* fid_codes
[cfid
] * 100;
freqs.
new = powernow_table
[index
].
frequency;
cpufreq_notify_transition
(&freqs
, CPUFREQ_PRECHANGE
);
/* Now do the magic poking into the MSRs. */
if (have_a0
== 1) /* A0 errata 5 */
local_irq_disable
();
if (freqs.
old > freqs.
new) {
/* Going down, so change FID first */
change_FID
(fid
);
change_VID
(vid
);
} else {
/* Going up, so change VID first */
change_VID
(vid
);
change_FID
(fid
);
}
if (have_a0
== 1)
local_irq_enable
();
cpufreq_notify_transition
(&freqs
, CPUFREQ_POSTCHANGE
);
}
static int powernow_decode_bios
(int maxfid
, int startvid
)
{
struct psb_s
*psb
;
struct pst_s
*pst
;
struct cpuinfo_x86
*c
= &new_cpu_data
; /* Nino */
unsigned int i
, j
;
unsigned char *p
;
unsigned int etuple
;
unsigned int ret
;
etuple
= cpuid_eax
(0x80000001);
etuple
&= 0xf00;
etuple
|= (c
->x86_model
<<4)|(c
->x86_mask
);
for (i
=0xC0000; i
< 0xffff0 ; i
+=16) {
p
= phys_to_virt
(i
);
if (memcmp(p
, "AMDK7PNOW!", 10) == 0){
dprintk
(KERN_INFO PFX
"Found PSB header at %p\n", p
);
psb
= (struct psb_s
*) p
;
dprintk
(KERN_INFO PFX
"Table version: 0x%x\n", psb
->tableversion
);
if (psb
->tableversion
!= 0x12) {
printk
(KERN_INFO PFX
"Sorry, only v1.2 tables supported right now\n");
return -ENODEV
;
}
dprintk
(KERN_INFO PFX
"Flags: 0x%x (", psb
->flags
);
if ((psb
->flags
& 1)==0) {
dprintk
("Mobile");
} else {
dprintk
("Desktop");
}
dprintk
(" voltage regulator)\n");
latency
= psb
->settlingtime
;
if (latency
< 100) {
printk
(KERN_INFO PFX
"BIOS set settling time to %d microseconds."
"Should be at least 100. Correcting.\n", latency
);
latency
= 100;
}
dprintk
(KERN_INFO PFX
"Settling Time: %d microseconds.\n", psb
->settlingtime
);
dprintk
(KERN_INFO PFX
"Has %d PST tables. (Only dumping ones relevant to this CPU).\n", psb
->numpst
);
latency
*= 100; /* SGTC needs to be in units of 10ns */
p
+= sizeof (struct psb_s
);
pst
= (struct pst_s
*) p
;
for (i
= 0 ; i
<psb
->numpst
; i
++) {
pst
= (struct pst_s
*) p
;
number_scales
= pst
->numpstates
;
if ((etuple
== pst
->cpuid
) && (maxfid
==pst
->maxfid
) && (startvid
==pst
->startvid
))
{
dprintk
(KERN_INFO PFX
"PST:%d (@%p)\n", i
, pst
);
dprintk
(KERN_INFO PFX
" cpuid: 0x%x\t", pst
->cpuid
);
dprintk
("fsb: %d\t", pst
->fsbspeed
);
dprintk
("maxFID: 0x%x\t", pst
->maxfid
);
dprintk
("startvid: 0x%x\n", pst
->startvid
);
fsb
= pst
->fsbspeed
;
ret
= get_ranges
((char *) pst
+ sizeof (struct pst_s
));
return ret
;
} else {
p
= (char *) pst
+ sizeof (struct pst_s
);
for (j
=0 ; j
< number_scales
; j
++)
p
+=2;
}
}
printk
(KERN_INFO PFX
"No PST tables match this cpuid (0x%x)\n", etuple
);
printk
("This is indicative of a broken BIOS. Email davej@redhat.com\n");
return -EINVAL
;
}
p
++;
}
return -ENODEV
;
}
static int powernow_target
(struct cpufreq_policy
*policy
,
unsigned int target_freq
,
unsigned int relation
)
{
unsigned int newstate
;
if (cpufreq_frequency_table_target
(policy
, powernow_table
, target_freq
, relation
, &newstate
))
return -EINVAL
;
change_speed
(newstate
);
return 0;
}
static int powernow_verify
(struct cpufreq_policy
*policy
)
{
return cpufreq_frequency_table_verify
(policy
, powernow_table
);
}
static int __init powernow_cpu_init
(struct cpufreq_policy
*policy
)
{
union msr_fidvidstatus fidvidstatus
;
int result
;
if (policy
->cpu
!= 0)
return -ENODEV
;
rdmsrl
(MSR_K7_FID_VID_STATUS
, fidvidstatus.
val);
result
= powernow_decode_bios
(fidvidstatus.
bits.
MFID, fidvidstatus.
bits.
SVID);
if (result
)
return result
;
printk
(KERN_INFO PFX
"Minimum speed %d MHz. Maximum speed %d MHz.\n",
minimum_speed
, maximum_speed
);
policy
->governor
= 0; //!!!CPUFREQ_DEFAULT_GOVERNOR;
policy
->cpuinfo.
transition_latency = latency
;
policy
->cur
= maximum_speed
;
return cpufreq_frequency_table_cpuinfo
(policy
, powernow_table
);
}
static struct cpufreq_driver powernow_driver
= {
.
verify = powernow_verify
,
.
target = powernow_target
,
.
init = powernow_cpu_init
,
.
name = "powernow-k7",
.
owner = THIS_MODULE
,
};
/*static*/ int __init powernow_init
(void)
{
/*!!!if (dmi_broken & BROKEN_CPUFREQ) {
printk (KERN_INFO PFX "Disabled at boot time by DMI,\n");
return -ENODEV;
}*/
if (check_powernow
()==0)
return -ENODEV
;
return cpufreq_register_driver
(&powernow_driver
);
}
/*static*/ void __exit powernow_exit
(void)
{
cpufreq_unregister_driver
(&powernow_driver
);
if (powernow_table
)
kfree
(powernow_table
);
}
MODULE_AUTHOR
("Dave Jones <davej@codemonkey.org.uk>");
MODULE_DESCRIPTION
("Powernow driver for AMD K7 processors.");
MODULE_LICENSE
("GPL");
module_init
(powernow_init
);
module_exit
(powernow_exit
);