/*
hwmon-vid.c - VID/VRM/VRD voltage conversions
Copyright (c) 2004 Rudolf Marek <r.marek@sh.cvut.cz>
Partly imported from i2c-vid.h of the lm_sensors project
Copyright (c) 2002 Mark D. Studebaker <mdsxyz123@yahoo.com>
With assistance from Trent Piepho <xyzzy@speakeasy.org>
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/hwmon-vid.h>
/*
Common code for decoding VID pins.
References:
For VRM 8.4 to 9.1, "VRM x.y DC-DC Converter Design Guidelines",
available at http://developer.intel.com/.
For VRD 10.0 and up, "VRD x.y Design Guide",
available at http://developer.intel.com/.
AMD Opteron processors don't follow the Intel specifications.
I'm going to "make up" 2.4 as the spec number for the Opterons.
No good reason just a mnemonic for the 24x Opteron processor
series.
Opteron VID encoding is:
00000 = 1.550 V
00001 = 1.525 V
. . . .
11110 = 0.800 V
11111 = 0.000 V (off)
The 17 specification is in fact Intel Mobile Voltage Positioning -
(IMVP-II). You can find more information in the datasheet of Max1718
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2452
The 13 specification corresponds to the Intel Pentium M series. There
doesn't seem to be any named specification for these. The conversion
tables are detailed directly in the various Pentium M datasheets:
http://www.intel.com/design/intarch/pentiumm/docs_pentiumm.htm
*/
/* vrm is the VRM/VRD document version multiplied by 10.
val is the 4-, 5- or 6-bit VID code.
Returned value is in mV to avoid floating point in the kernel. */
int vid_from_reg(int val, u8 vrm)
{
int vid;
switch(vrm) {
case 100: /* VRD 10.0 */
if((val & 0x1f) == 0x1f)
return 0;
if((val & 0x1f) <= 0x09 || val == 0x0a)
vid = 10875 - (val & 0x1f) * 250;
else
vid = 18625 - (val & 0x1f) * 250;
if(val & 0x20)
vid -= 125;
vid /= 10; /* only return 3 dec. places for now */
return vid;
case 24: /* Opteron processor */
return(val == 0x1f ? 0 : 1550 - val * 25);
case 91: /* VRM 9.1 */
case 90: /* VRM 9.0 */
return(val == 0x1f ? 0 :
1850 - val * 25);
case 85: /* VRM 8.5 */
return((val & 0x10 ? 25 : 0) +
((val & 0x0f) > 0x04 ? 2050 : 1250) -
((val & 0x0f) * 50));
case 84: /* VRM 8.4 */
val &= 0x0f;
/* fall through */
case 82: /* VRM 8.2 */
return(val == 0x1f ? 0 :
val & 0x10 ? 5100 - (val) * 100 :
2050 - (val) * 50);
case 17: /* Intel IMVP-II */
return(val & 0x10 ? 975 - (val & 0xF) * 25 :
1750 - val * 50);
case 13:
return(1708 - (val & 0x3f) * 16);
default: /* report 0 for unknown */
printk(KERN_INFO "hwmon-vid: requested unknown VRM version\n");
return 0;
}
}
/*
After this point is the code to automatically determine which
VRM/VRD specification should be used depending on the CPU.
*/
struct vrm_model {
u8 vendor;
u8 eff_family;
u8 eff_model;
u8 eff_stepping;
u8 vrm_type;
};
#define ANY 0xFF
#ifdef CONFIG_X86
/* the stepping parameter is highest acceptable stepping for current line */
static struct vrm_model vrm_models[] = {
{X86_VENDOR_AMD, 0x6, ANY, ANY, 90}, /* Athlon Duron etc */
{X86_VENDOR_AMD, 0xF, ANY, ANY, 24}, /* Athlon 64, Opteron and above VRM 24 */
{X86_VENDOR_INTEL, 0x6, 0x9, ANY, 13}, /* Pentium M (130 nm) */
{X86_VENDOR_INTEL, 0x6, 0xB, ANY, 85}, /* Tualatin */
{X86_VENDOR_INTEL, 0x6, 0xD, ANY, 13}, /* Pentium M (90 nm) */
{X86_VENDOR_INTEL, 0x6, ANY, ANY, 82}, /* any P6 */
{X86_VENDOR_INTEL, 0x7, ANY, ANY, 0}, /* Itanium */
{X86_VENDOR_INTEL, 0xF, 0x0, ANY, 90}, /* P4 */
{X86_VENDOR_INTEL, 0xF, 0x1, ANY, 90}, /* P4 Willamette */
{X86_VENDOR_INTEL, 0xF, 0x2, ANY, 90}, /* P4 Northwood */
{X86_VENDOR_INTEL, 0xF, ANY, ANY, 100}, /* Prescott and above assume VRD 10 */
{X86_VENDOR_INTEL, 0x10, ANY, ANY, 0}, /* Itanium 2 */
{X86_VENDOR_CENTAUR, 0x6, 0x7, ANY, 85}, /* Eden ESP/Ezra */
{X86_VENDOR_CENTAUR, 0x6, 0x8, 0x7, 85}, /* Ezra T */
{X86_VENDOR_CENTAUR, 0x6, 0x9, 0x7, 85}, /* Nemiah */
{X86_VENDOR_CENTAUR, 0x6, 0x9, ANY, 17}, /* C3-M */
{X86_VENDOR_UNKNOWN, ANY, ANY, ANY, 0} /* stop here */
};
static u8 find_vrm(u8 eff_family, u8 eff_model, u8 eff_stepping, u8 vendor)
{
int i = 0;
while (vrm_models[i].vendor!=X86_VENDOR_UNKNOWN) {
if (vrm_models[i].vendor==vendor)
if ((vrm_models[i].eff_family==eff_family)
&& ((vrm_models[i].eff_model==eff_model) ||
(vrm_models[i].eff_model==ANY)) &&
(eff_stepping <= vrm_models[i].eff_stepping))
return vrm_models[i].vrm_type;
i++;
}
return 0;
}
u8 vid_which_vrm(void)
{
struct cpuinfo_x86 *c = cpu_data;
u32 eax;
u8 eff_family, eff_model, eff_stepping, vrm_ret;
if (c->x86 < 6) /* Any CPU with family lower than 6 */
return 0; /* doesn't have VID and/or CPUID */
eax = cpuid_eax(1);
eff_family = ((eax & 0x00000F00)>>8);
eff_model = ((eax & 0x000000F0)>>4);
eff_stepping = eax & 0xF;
if (eff_family == 0xF) { /* use extended model & family */
eff_family += ((eax & 0x00F00000)>>20);
eff_model += ((eax & 0x000F0000)>>16)<<4;
}
vrm_ret = find_vrm(eff_family, eff_model, eff_stepping, c->x86_vendor);
if (vrm_ret == 0)
printk(KERN_INFO "hwmon-vid: Unknown VRM version of your "
"x86 CPU\n");
return vrm_ret;
}
/* and now for something completely different for the non-x86 world */
#else
u8 vid_which_vrm(void)
{
printk(KERN_INFO "hwmon-vid: Unknown VRM version of your CPU\n");
return 0;
}
#endif
EXPORT_SYMBOL(vid_from_reg);
EXPORT_SYMBOL(vid_which_vrm);
MODULE_AUTHOR("Rudolf Marek <r.marek@sh.cvut.cz>");
MODULE_DESCRIPTION("hwmon-vid driver");
MODULE_LICENSE("GPL");
