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LeafOS / LeafOS-Devices / android_kernel_samsung_gta4xl / c172cb73bc79fe69915b1a1a48e374aa4b1f8a59 / . / arch / x86 / kernel / cpu / cpufreq / powernow-k8.c
blob: 3e90cce3dc8bfe50fa245e8febe2aaf2625df25e [file] [log] [blame]
/*
* (c) 2003-2010 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
*
* Support : mark.langsdorf@amd.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@suse.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 for the AMD Athlon 64 and AMD
* Opteron Processors" available for download from www.amd.com
*
* Tables for specific CPUs can be inferred from
* http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/30430.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/sched.h> /* for current / set_cpus_allowed() */
#include <linux/io.h>
#include <linux/delay.h>
#include <asm/msr.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"
#include "mperf.h"
/* serialize freq changes */
static DEFINE_MUTEX(fidvid_mutex);
static DEFINE_PER_CPU(struct powernow_k8_data *, powernow_data);
static int cpu_family = CPU_OPTERON;
/* core performance boost */
static bool cpb_capable, cpb_enabled;
static struct msr __percpu *msrs;
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);
}
static u32 find_khz_freq_from_pstate(struct cpufreq_frequency_table *data,
u32 pstate)
{
return data[pstate].frequency;
}
/* 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;
if (cpu_family == CPU_HW_PSTATE)
return 0;
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;
if (cpu_family == CPU_HW_PSTATE) {
rdmsr(MSR_PSTATE_STATUS, lo, hi);
i = lo & HW_PSTATE_MASK;
data->currpstate = i;
/*
* a workaround for family 11h erratum 311 might cause
* an "out-of-range Pstate if the core is in Pstate-0
*/
if ((boot_cpu_data.x86 == 0x11) && (i >= data->numps))
data->currpstate = HW_PSTATE_0;
return 0;
}
do {
if (i++ > 10000) {
dprintk("detected change pending stuck\n");
return 1;
}
rdmsr(MSR_FIDVID_STATUS, lo, hi);
} while (lo & MSR_S_LO_CHANGE_PENDING);
data->currvid = hi & MSR_S_HI_CURRENT_VID;
data->currfid = lo & MSR_S_LO_CURRENT_FID;
return 0;
}
/* the isochronous relief time */
static void count_off_irt(struct powernow_k8_data *data)
{
udelay((1 << data->irt) * 10);
return;
}
/* the voltage stabilization time */
static void count_off_vst(struct powernow_k8_data *data)
{
udelay(data->vstable * VST_UNITS_20US);
return;
}
/* need to init the control msr to a safe value (for each cpu) */
static void fidvid_msr_init(void)
{
u32 lo, hi;
u8 fid, vid;
rdmsr(MSR_FIDVID_STATUS, lo, hi);
vid = hi & MSR_S_HI_CURRENT_VID;
fid = lo & MSR_S_LO_CURRENT_FID;
lo = fid | (vid << MSR_C_LO_VID_SHIFT);
hi = MSR_C_HI_STP_GNT_BENIGN;
dprintk("cpu%d, init lo 0x%x, hi 0x%x\n", smp_processor_id(), lo, hi);
wrmsr(MSR_FIDVID_CTL, lo, hi);
}
/* write the new fid value along with the other control fields to the msr */
static int write_new_fid(struct powernow_k8_data *data, u32 fid)
{
u32 lo;
u32 savevid = data->currvid;
u32 i = 0;
if ((fid & INVALID_FID_MASK) || (data->currvid & INVALID_VID_MASK)) {
printk(KERN_ERR PFX "internal error - overflow on fid write\n");
return 1;
}
lo = fid;
lo |= (data->currvid << MSR_C_LO_VID_SHIFT);
lo |= MSR_C_LO_INIT_FID_VID;
dprintk("writing fid 0x%x, lo 0x%x, hi 0x%x\n",
fid, lo, data->plllock * PLL_LOCK_CONVERSION);
do {
wrmsr(MSR_FIDVID_CTL, lo, data->plllock * PLL_LOCK_CONVERSION);
if (i++ > 100) {
printk(KERN_ERR PFX
"Hardware error - pending bit very stuck - "
"no further pstate changes possible\n");
return 1;
}
} while (query_current_values_with_pending_wait(data));
count_off_irt(data);
if (savevid != data->currvid) {
printk(KERN_ERR PFX
"vid change on fid trans, old 0x%x, new 0x%x\n",
savevid, data->currvid);
return 1;
}
if (fid != data->currfid) {
printk(KERN_ERR PFX
"fid trans failed, fid 0x%x, curr 0x%x\n", fid,
data->currfid);
return 1;
}
return 0;
}
/* Write a new vid to the hardware */
static int write_new_vid(struct powernow_k8_data *data, u32 vid)
{
u32 lo;
u32 savefid = data->currfid;
int i = 0;
if ((data->currfid & INVALID_FID_MASK) || (vid & INVALID_VID_MASK)) {
printk(KERN_ERR PFX "internal error - overflow on vid write\n");
return 1;
}
lo = data->currfid;
lo |= (vid << MSR_C_LO_VID_SHIFT);
lo |= MSR_C_LO_INIT_FID_VID;
dprintk("writing vid 0x%x, lo 0x%x, hi 0x%x\n",
vid, lo, STOP_GRANT_5NS);
do {
wrmsr(MSR_FIDVID_CTL, lo, STOP_GRANT_5NS);
if (i++ > 100) {
printk(KERN_ERR PFX "internal error - pending bit "
"very stuck - no further pstate "
"changes possible\n");
return 1;
}
} while (query_current_values_with_pending_wait(data));
if (savefid != data->currfid) {
printk(KERN_ERR PFX "fid changed on vid trans, old "
"0x%x new 0x%x\n",
savefid, data->currfid);
return 1;
}
if (vid != data->currvid) {
printk(KERN_ERR PFX "vid trans failed, vid 0x%x, "
"curr 0x%x\n",
vid, data->currvid);
return 1;
}
return 0;
}
/*
* Reduce the vid by the max of step or reqvid.
* Decreasing vid codes represent increasing voltages:
* vid of 0 is 1.550V, vid of 0x1e is 0.800V, vid of VID_OFF is off.
*/
static int decrease_vid_code_by_step(struct powernow_k8_data *data,
u32 reqvid, u32 step)
{
if ((data->currvid - reqvid) > step)
reqvid = data->currvid - step;
if (write_new_vid(data, reqvid))
return 1;
count_off_vst(data);
return 0;
}
/* Change hardware pstate by single MSR write */
static int transition_pstate(struct powernow_k8_data *data, u32 pstate)
{
wrmsr(MSR_PSTATE_CTRL, pstate, 0);
data->currpstate = pstate;
return 0;
}
/* Change Opteron/Athlon64 fid and vid, by the 3 phases. */
static int transition_fid_vid(struct powernow_k8_data *data,
u32 reqfid, u32 reqvid)
{
if (core_voltage_pre_transition(data, reqvid, reqfid))
return 1;
if (core_frequency_transition(data, reqfid))
return 1;
if (core_voltage_post_transition(data, reqvid))
return 1;
if (query_current_values_with_pending_wait(data))
return 1;
if ((reqfid != data->currfid) || (reqvid != data->currvid)) {
printk(KERN_ERR PFX "failed (cpu%d): req 0x%x 0x%x, "
"curr 0x%x 0x%x\n",
smp_processor_id(),
reqfid, reqvid, data->currfid, data->currvid);
return 1;
}
dprintk("transitioned (cpu%d): new fid 0x%x, vid 0x%x\n",
smp_processor_id(), data->currfid, data->currvid);
return 0;
}
/* Phase 1 - core voltage transition ... setup voltage */
static int core_voltage_pre_transition(struct powernow_k8_data *data,
u32 reqvid, u32 reqfid)
{
u32 rvosteps = data->rvo;
u32 savefid = data->currfid;
u32 maxvid, lo, rvomult = 1;
dprintk("ph1 (cpu%d): start, currfid 0x%x, currvid 0x%x, "
"reqvid 0x%x, rvo 0x%x\n",
smp_processor_id(),
data->currfid, data->currvid, reqvid, data->rvo);
if ((savefid < LO_FID_TABLE_TOP) && (reqfid < LO_FID_TABLE_TOP))
rvomult = 2;
rvosteps *= rvomult;
rdmsr(MSR_FIDVID_STATUS, lo, maxvid);
maxvid = 0x1f & (maxvid >> 16);
dprintk("ph1 maxvid=0x%x\n", maxvid);
if (reqvid < maxvid) /* lower numbers are higher voltages */
reqvid = maxvid;
while (data->currvid > reqvid) {
dprintk("ph1: curr 0x%x, req vid 0x%x\n",
data->currvid, reqvid);
if (decrease_vid_code_by_step(data, reqvid, data->vidmvs))
return 1;
}
while ((rvosteps > 0) &&
((rvomult * data->rvo + data->currvid) > reqvid)) {
if (data->currvid == maxvid) {
rvosteps = 0;
} else {
dprintk("ph1: changing vid for rvo, req 0x%x\n",
data->currvid - 1);
if (decrease_vid_code_by_step(data, data->currvid-1, 1))
return 1;
rvosteps--;
}
}
if (query_current_values_with_pending_wait(data))
return 1;
if (savefid != data->currfid) {
printk(KERN_ERR PFX "ph1 err, currfid changed 0x%x\n",
data->currfid);
return 1;
}
dprintk("ph1 complete, currfid 0x%x, currvid 0x%x\n",
data->currfid, data->currvid);
return 0;
}
/* Phase 2 - core frequency transition */
static int core_frequency_transition(struct powernow_k8_data *data, u32 reqfid)
{
u32 vcoreqfid, vcocurrfid, vcofiddiff;
u32 fid_interval, savevid = data->currvid;
if (data->currfid == reqfid) {
printk(KERN_ERR PFX "ph2 null fid transition 0x%x\n",
data->currfid);
return 0;
}
dprintk("ph2 (cpu%d): starting, currfid 0x%x, currvid 0x%x, "
"reqfid 0x%x\n",
smp_processor_id(),
data->currfid, data->currvid, reqfid);
vcoreqfid = convert_fid_to_vco_fid(reqfid);
vcocurrfid = convert_fid_to_vco_fid(data->currfid);
vcofiddiff = vcocurrfid > vcoreqfid ? vcocurrfid - vcoreqfid
: vcoreqfid - vcocurrfid;
if ((reqfid <= LO_FID_TABLE_TOP) && (data->currfid <= LO_FID_TABLE_TOP))
vcofiddiff = 0;
while (vcofiddiff > 2) {
(data->currfid & 1) ? (fid_interval = 1) : (fid_interval = 2);
if (reqfid > data->currfid) {
if (data->currfid > LO_FID_TABLE_TOP) {
if (write_new_fid(data,
data->currfid + fid_interval))
return 1;
} else {
if (write_new_fid
(data,
2 + convert_fid_to_vco_fid(data->currfid)))
return 1;
}
} else {
if (write_new_fid(data, data->currfid - fid_interval))
return 1;
}
vcocurrfid = convert_fid_to_vco_fid(data->currfid);
vcofiddiff = vcocurrfid > vcoreqfid ? vcocurrfid - vcoreqfid
: vcoreqfid - vcocurrfid;
}
if (write_new_fid(data, reqfid))
return 1;
if (query_current_values_with_pending_wait(data))
return 1;
if (data->currfid != reqfid) {
printk(KERN_ERR PFX
"ph2: mismatch, failed fid transition, "
"curr 0x%x, req 0x%x\n",
data->currfid, reqfid);
return 1;
}
if (savevid != data->currvid) {
printk(KERN_ERR PFX "ph2: vid changed, save 0x%x, curr 0x%x\n",
savevid, data->currvid);
return 1;
}
dprintk("ph2 complete, currfid 0x%x, currvid 0x%x\n",
data->currfid, data->currvid);
return 0;
}
/* Phase 3 - core voltage transition flow ... jump to the final vid. */
static int core_voltage_post_transition(struct powernow_k8_data *data,
u32 reqvid)
{
u32 savefid = data->currfid;
u32 savereqvid = reqvid;
dprintk("ph3 (cpu%d): starting, currfid 0x%x, currvid 0x%x\n",
smp_processor_id(),
data->currfid, data->currvid);
if (reqvid != data->currvid) {
if (write_new_vid(data, reqvid))
return 1;
if (savefid != data->currfid) {
printk(KERN_ERR PFX
"ph3: bad fid change, save 0x%x, curr 0x%x\n",
savefid, data->currfid);
return 1;
}
if (data->currvid != reqvid) {
printk(KERN_ERR PFX
"ph3: failed vid transition\n, "
"req 0x%x, curr 0x%x",
reqvid, data->currvid);
return 1;
}
}
if (query_current_values_with_pending_wait(data))
return 1;
if (savereqvid != data->currvid) {
dprintk("ph3 failed, currvid 0x%x\n", data->currvid);
return 1;
}
if (savefid != data->currfid) {
dprintk("ph3 failed, currfid changed 0x%x\n",
data->currfid);
return 1;
}
dprintk("ph3 complete, currfid 0x%x, currvid 0x%x\n",
data->currfid, data->currvid);
return 0;
}
static void check_supported_cpu(void *_rc)
{
u32 eax, ebx, ecx, edx;
int *rc = _rc;
*rc = -ENODEV;
if (current_cpu_data.x86_vendor != X86_VENDOR_AMD)
return;
eax = cpuid_eax(CPUID_PROCESSOR_SIGNATURE);
if (((eax & CPUID_XFAM) != CPUID_XFAM_K8) &&
((eax & CPUID_XFAM) < CPUID_XFAM_10H))
return;
if ((eax & CPUID_XFAM) == CPUID_XFAM_K8) {
if (((eax & CPUID_USE_XFAM_XMOD) != CPUID_USE_XFAM_XMOD) ||
((eax & CPUID_XMOD) > CPUID_XMOD_REV_MASK)) {
printk(KERN_INFO PFX
"Processor cpuid %x not supported\n", eax);
return;
}
eax = cpuid_eax(CPUID_GET_MAX_CAPABILITIES);
if (eax < CPUID_FREQ_VOLT_CAPABILITIES) {
printk(KERN_INFO PFX
"No frequency change capabilities detected\n");
return;
}
cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);
if ((edx & P_STATE_TRANSITION_CAPABLE)
!= P_STATE_TRANSITION_CAPABLE) {
printk(KERN_INFO PFX
"Power state transitions not supported\n");
return;
}
} else { /* must be a HW Pstate capable processor */
cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);
if ((edx & USE_HW_PSTATE) == USE_HW_PSTATE)
cpu_family = CPU_HW_PSTATE;
else
return;
}
*rc = 0;
}
static int check_pst_table(struct powernow_k8_data *data, struct pst_s *pst,
u8 maxvid)
{
unsigned int j;
u8 lastfid = 0xff;
for (j = 0; j < data->numps; j++) {
if (pst[j].vid > LEAST_VID) {
printk(KERN_ERR FW_BUG PFX "vid %d invalid : 0x%x\n",
j, pst[j].vid);
return -EINVAL;
}
if (pst[j].vid < data->rvo) {
/* vid + rvo >= 0 */
printk(KERN_ERR FW_BUG PFX "0 vid exceeded with pstate"
" %d\n", j);
return -ENODEV;
}
if (pst[j].vid < maxvid + data->rvo) {
/* vid + rvo >= maxvid */
printk(KERN_ERR FW_BUG PFX "maxvid exceeded with pstate"
" %d\n", j);
return -ENODEV;
}
if (pst[j].fid > MAX_FID) {
printk(KERN_ERR FW_BUG PFX "maxfid exceeded with pstate"
" %d\n", j);
return -ENODEV;
}
if (j && (pst[j].fid < HI_FID_TABLE_BOTTOM)) {
/* Only first fid is allowed to be in "low" range */
printk(KERN_ERR FW_BUG PFX "two low fids - %d : "
"0x%x\n", j, pst[j].fid);
return -EINVAL;
}
if (pst[j].fid < lastfid)
lastfid = pst[j].fid;
}
if (lastfid & 1) {
printk(KERN_ERR FW_BUG PFX "lastfid invalid\n");
return -EINVAL;
}
if (lastfid > LO_FID_TABLE_TOP)
printk(KERN_INFO FW_BUG PFX
"first fid not from lo freq table\n");
return 0;
}
static void invalidate_entry(struct cpufreq_frequency_table *powernow_table,
unsigned int entry)
{
powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
}
static void print_basics(struct powernow_k8_data *data)
{
int j;
for (j = 0; j < data->numps; j++) {
if (data->powernow_table[j].frequency !=
CPUFREQ_ENTRY_INVALID) {
if (cpu_family == CPU_HW_PSTATE) {
printk(KERN_INFO PFX
" %d : pstate %d (%d MHz)\n", j,
data->powernow_table[j].index,
data->powernow_table[j].frequency/1000);
} else {
printk(KERN_INFO PFX
" %d : fid 0x%x (%d MHz), vid 0x%x\n",
j,
data->powernow_table[j].index & 0xff,
data->powernow_table[j].frequency/1000,
data->powernow_table[j].index >> 8);
}
}
}
if (data->batps)
printk(KERN_INFO PFX "Only %d pstates on battery\n",
data->batps);
}
static u32 freq_from_fid_did(u32 fid, u32 did)
{
u32 mhz = 0;
if (boot_cpu_data.x86 == 0x10)
mhz = (100 * (fid + 0x10)) >> did;
else if (boot_cpu_data.x86 == 0x11)
mhz = (100 * (fid + 8)) >> did;
else
BUG();
return mhz * 1000;
}
static int fill_powernow_table(struct powernow_k8_data *data,
struct pst_s *pst, u8 maxvid)
{
struct cpufreq_frequency_table *powernow_table;
unsigned int j;
if (data->batps) {
/* use ACPI support to get full speed on mains power */
printk(KERN_WARNING PFX
"Only %d pstates usable (use ACPI driver for full "
"range\n", data->batps);
data->numps = data->batps;
}
for (j = 1; j < data->numps; j++) {
if (pst[j-1].fid >= pst[j].fid) {
printk(KERN_ERR PFX "PST out of sequence\n");
return -EINVAL;
}
}
if (data->numps < 2) {
printk(KERN_ERR PFX "no p states to transition\n");
return -ENODEV;
}
if (check_pst_table(data, pst, maxvid))
return -EINVAL;
powernow_table = kmalloc((sizeof(struct cpufreq_frequency_table)
* (data->numps + 1)), GFP_KERNEL);
if (!powernow_table) {
printk(KERN_ERR PFX "powernow_table memory alloc failure\n");
return -ENOMEM;
}
for (j = 0; j < data->numps; j++) {
int freq;
powernow_table[j].index = pst[j].fid; /* lower 8 bits */
powernow_table[j].index |= (pst[j].vid << 8); /* upper 8 bits */
freq = find_khz_freq_from_fid(pst[j].fid);
powernow_table[j].frequency = freq;
}
powernow_table[data->numps].frequency = CPUFREQ_TABLE_END;
powernow_table[data->numps].index = 0;
if (query_current_values_with_pending_wait(data)) {
kfree(powernow_table);
return -EIO;
}
dprintk("cfid 0x%x, cvid 0x%x\n", data->currfid, data->currvid);
data->powernow_table = powernow_table;
if (cpumask_first(cpu_core_mask(data->cpu)) == data->cpu)
print_basics(data);
for (j = 0; j < data->numps; j++)
if ((pst[j].fid == data->currfid) &&
(pst[j].vid == data->currvid))
return 0;
dprintk("currfid/vid do not match PST, ignoring\n");
return 0;
}
/* Find and validate the PSB/PST table in BIOS. */
static int find_psb_table(struct powernow_k8_data *data)
{
struct psb_s *psb;
unsigned int i;
u32 mvs;
u8 maxvid;
u32 cpst = 0;
u32 thiscpuid;
for (i = 0xc0000; i < 0xffff0; i += 0x10) {
/* Scan BIOS looking for the signature. */
/* It can not be at ffff0 - it is too big. */
psb = phys_to_virt(i);
if (memcmp(psb, PSB_ID_STRING, PSB_ID_STRING_LEN) != 0)
continue;
dprintk("found PSB header at 0x%p\n", psb);
dprintk("table vers: 0x%x\n", psb->tableversion);
if (psb->tableversion != PSB_VERSION_1_4) {
printk(KERN_ERR FW_BUG PFX "PSB table is not v1.4\n");
return -ENODEV;
}
dprintk("flags: 0x%x\n", psb->flags1);
if (psb->flags1) {
printk(KERN_ERR FW_BUG PFX "unknown flags\n");
return -ENODEV;
}
data->vstable = psb->vstable;
dprintk("voltage stabilization time: %d(*20us)\n",
data->vstable);
dprintk("flags2: 0x%x\n", psb->flags2);
data->rvo = psb->flags2 & 3;
data->irt = ((psb->flags2) >> 2) & 3;
mvs = ((psb->flags2) >> 4) & 3;
data->vidmvs = 1 << mvs;
data->batps = ((psb->flags2) >> 6) & 3;
dprintk("ramp voltage offset: %d\n", data->rvo);
dprintk("isochronous relief time: %d\n", data->irt);
dprintk("maximum voltage step: %d - 0x%x\n", mvs, data->vidmvs);
dprintk("numpst: 0x%x\n", psb->num_tables);
cpst = psb->num_tables;
if ((psb->cpuid == 0x00000fc0) ||
(psb->cpuid == 0x00000fe0)) {
thiscpuid = cpuid_eax(CPUID_PROCESSOR_SIGNATURE);
if ((thiscpuid == 0x00000fc0) ||
(thiscpuid == 0x00000fe0))
cpst = 1;
}
if (cpst != 1) {
printk(KERN_ERR FW_BUG PFX "numpst must be 1\n");
return -ENODEV;
}
data->plllock = psb->plllocktime;
dprintk("plllocktime: 0x%x (units 1us)\n", psb->plllocktime);
dprintk("maxfid: 0x%x\n", psb->maxfid);
dprintk("maxvid: 0x%x\n", psb->maxvid);
maxvid = psb->maxvid;
data->numps = psb->numps;
dprintk("numpstates: 0x%x\n", data->numps);
return fill_powernow_table(data,
(struct pst_s *)(psb+1), maxvid);
}
/*
* If you see this message, complain to BIOS manufacturer. If
* he tells you "we do not support Linux" or some similar
* nonsense, remember that Windows 2000 uses the same legacy
* mechanism that the old Linux PSB driver uses. Tell them it
* is broken with Windows 2000.
*
* The reference to the AMD documentation is chapter 9 in the
* BIOS and Kernel Developer's Guide, which is available on
* www.amd.com
*/
printk(KERN_ERR FW_BUG PFX "No PSB or ACPI _PSS objects\n");
return -ENODEV;
}
static void powernow_k8_acpi_pst_values(struct powernow_k8_data *data,
unsigned int index)
{
u64 control;
if (!data->acpi_data.state_count || (cpu_family == CPU_HW_PSTATE))
return;
control = data->acpi_data.states[index].control;
data->irt = (control >> IRT_SHIFT) & IRT_MASK;
data->rvo = (control >> RVO_SHIFT) & RVO_MASK;
data->exttype = (control >> EXT_TYPE_SHIFT) & EXT_TYPE_MASK;
data->plllock = (control >> PLL_L_SHIFT) & PLL_L_MASK;
data->vidmvs = 1 << ((control >> MVS_SHIFT) & MVS_MASK);
data->vstable = (control >> VST_SHIFT) & VST_MASK;
}
static int powernow_k8_cpu_init_acpi(struct powernow_k8_data *data)
{
struct cpufreq_frequency_table *powernow_table;
int ret_val = -ENODEV;
u64 control, status;
if (acpi_processor_register_performance(&data->acpi_data, data->cpu)) {
dprintk("register performance failed: bad ACPI data\n");
return -EIO;
}
/* verify the data contained in the ACPI structures */
if (data->acpi_data.state_count <= 1) {
dprintk("No ACPI P-States\n");
goto err_out;
}
control = data->acpi_data.control_register.space_id;
status = data->acpi_data.status_register.space_id;
if ((control != ACPI_ADR_SPACE_FIXED_HARDWARE) ||
(status != ACPI_ADR_SPACE_FIXED_HARDWARE)) {
dprintk("Invalid control/status registers (%x - %x)\n",
control, status);
goto err_out;
}
/* fill in data->powernow_table */
powernow_table = kmalloc((sizeof(struct cpufreq_frequency_table)
* (data->acpi_data.state_count + 1)), GFP_KERNEL);
if (!powernow_table) {
dprintk("powernow_table memory alloc failure\n");
goto err_out;
}
/* fill in data */
data->numps = data->acpi_data.state_count;
powernow_k8_acpi_pst_values(data, 0);
if (cpu_family == CPU_HW_PSTATE)
ret_val = fill_powernow_table_pstate(data, powernow_table);
else
ret_val = fill_powernow_table_fidvid(data, powernow_table);
if (ret_val)
goto err_out_mem;
powernow_table[data->acpi_data.state_count].frequency =
CPUFREQ_TABLE_END;
powernow_table[data->acpi_data.state_count].index = 0;
data->powernow_table = powernow_table;
if (cpumask_first(cpu_core_mask(data->cpu)) == data->cpu)
print_basics(data);
/* notify BIOS that we exist */
acpi_processor_notify_smm(THIS_MODULE);
if (!zalloc_cpumask_var(&data->acpi_data.shared_cpu_map, GFP_KERNEL)) {
printk(KERN_ERR PFX
"unable to alloc powernow_k8_data cpumask\n");
ret_val = -ENOMEM;
goto err_out_mem;
}
return 0;
err_out_mem:
kfree(powernow_table);
err_out:
acpi_processor_unregister_performance(&data->acpi_data, data->cpu);
/* data->acpi_data.state_count informs us at ->exit()
* whether ACPI was used */
data->acpi_data.state_count = 0;
return ret_val;
}
static int fill_powernow_table_pstate(struct powernow_k8_data *data,
struct cpufreq_frequency_table *powernow_table)
{
int i;
u32 hi = 0, lo = 0;
rdmsr(MSR_PSTATE_CUR_LIMIT, hi, lo);
data->max_hw_pstate = (hi & HW_PSTATE_MAX_MASK) >> HW_PSTATE_MAX_SHIFT;
for (i = 0; i < data->acpi_data.state_count; i++) {
u32 index;
index = data->acpi_data.states[i].control & HW_PSTATE_MASK;
if (index > data->max_hw_pstate) {
printk(KERN_ERR PFX "invalid pstate %d - "
"bad value %d.\n", i, index);
printk(KERN_ERR PFX "Please report to BIOS "
"manufacturer\n");
invalidate_entry(powernow_table, i);
continue;
}
rdmsr(MSR_PSTATE_DEF_BASE + index, lo, hi);
if (!(hi & HW_PSTATE_VALID_MASK)) {
dprintk("invalid pstate %d, ignoring\n", index);
invalidate_entry(powernow_table, i);
continue;
}
powernow_table[i].index = index;
/* Frequency may be rounded for these */
if ((boot_cpu_data.x86 == 0x10 && boot_cpu_data.x86_model < 10)
|| boot_cpu_data.x86 == 0x11) {
powernow_table[i].frequency =
freq_from_fid_did(lo & 0x3f, (lo >> 6) & 7);
} else
powernow_table[i].frequency =
data->acpi_data.states[i].core_frequency * 1000;
}
return 0;
}
static int fill_powernow_table_fidvid(struct powernow_k8_data *data,
struct cpufreq_frequency_table *powernow_table)
{
int i;
for (i = 0; i < data->acpi_data.state_count; i++) {
u32 fid;
u32 vid;
u32 freq, index;
u64 status, control;
if (data->exttype) {
status = data->acpi_data.states[i].status;
fid = status & EXT_FID_MASK;
vid = (status >> VID_SHIFT) & EXT_VID_MASK;
} else {
control = data->acpi_data.states[i].control;
fid = control & FID_MASK;
vid = (control >> VID_SHIFT) & VID_MASK;
}
dprintk(" %d : fid 0x%x, vid 0x%x\n", i, fid, vid);
index = fid | (vid<<8);
powernow_table[i].index = index;
freq = find_khz_freq_from_fid(fid);
powernow_table[i].frequency = freq;
/* verify frequency is OK */
if ((freq > (MAX_FREQ * 1000)) || (freq < (MIN_FREQ * 1000))) {
dprintk("invalid freq %u kHz, ignoring\n", freq);
invalidate_entry(powernow_table, i);
continue;
}
/* verify voltage is OK -
* BIOSs are using "off" to indicate invalid */
if (vid == VID_OFF) {
dprintk("invalid vid %u, ignoring\n", vid);
invalidate_entry(powernow_table, i);
continue;
}
if (freq != (data->acpi_data.states[i].core_frequency * 1000)) {
printk(KERN_INFO PFX "invalid freq entries "
"%u kHz vs. %u kHz\n", freq,
(unsigned int)
(data->acpi_data.states[i].core_frequency
* 1000));
invalidate_entry(powernow_table, i);
continue;
}
}
return 0;
}
static void powernow_k8_cpu_exit_acpi(struct powernow_k8_data *data)
{
if (data->acpi_data.state_count)
acpi_processor_unregister_performance(&data->acpi_data,
data->cpu);
free_cpumask_var(data->acpi_data.shared_cpu_map);
}
static int get_transition_latency(struct powernow_k8_data *data)
{
int max_latency = 0;
int i;
for (i = 0; i < data->acpi_data.state_count; i++) {
int cur_latency = data->acpi_data.states[i].transition_latency
+ data->acpi_data.states[i].bus_master_latency;
if (cur_latency > max_latency)
max_latency = cur_latency;
}
if (max_latency == 0) {
/*
* Fam 11h and later may return 0 as transition latency. This
* is intended and means "very fast". While cpufreq core and
* governors currently can handle that gracefully, better set it
* to 1 to avoid problems in the future.
*/
if (boot_cpu_data.x86 < 0x11)
printk(KERN_ERR FW_WARN PFX "Invalid zero transition "
"latency\n");
max_latency = 1;
}
/* value in usecs, needs to be in nanoseconds */
return 1000 * max_latency;
}
/* Take a frequency, and issue the fid/vid transition command */
static int transition_frequency_fidvid(struct powernow_k8_data *data,
unsigned int index)
{
u32 fid = 0;
u32 vid = 0;
int res, i;
struct cpufreq_freqs freqs;
dprintk("cpu %d transition to index %u\n", smp_processor_id(), index);
/* fid/vid correctness check for k8 */
/* fid are the lower 8 bits of the index we stored into
* the cpufreq frequency table in find_psb_table, vid
* are the upper 8 bits.
*/
fid = data->powernow_table[index].index & 0xFF;
vid = (data->powernow_table[index].index & 0xFF00) >> 8;
dprintk("table matched fid 0x%x, giving vid 0x%x\n", fid, vid);
if (query_current_values_with_pending_wait(data))
return 1;
if ((data->currvid == vid) && (data->currfid == fid)) {
dprintk("target matches current values (fid 0x%x, vid 0x%x)\n",
fid, vid);
return 0;
}
dprintk("cpu %d, changing to fid 0x%x, vid 0x%x\n",
smp_processor_id(), fid, vid);
freqs.old = find_khz_freq_from_fid(data->currfid);
freqs.new = find_khz_freq_from_fid(fid);
for_each_cpu(i, data->available_cores) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
res = transition_fid_vid(data, fid, vid);
freqs.new = find_khz_freq_from_fid(data->currfid);
for_each_cpu(i, data->available_cores) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
return res;
}
/* Take a frequency, and issue the hardware pstate transition command */
static int transition_frequency_pstate(struct powernow_k8_data *data,
unsigned int index)
{
u32 pstate = 0;
int res, i;
struct cpufreq_freqs freqs;
dprintk("cpu %d transition to index %u\n", smp_processor_id(), index);
/* get MSR index for hardware pstate transition */
pstate = index & HW_PSTATE_MASK;
if (pstate > data->max_hw_pstate)
return 0;
freqs.old = find_khz_freq_from_pstate(data->powernow_table,
data->currpstate);
freqs.new = find_khz_freq_from_pstate(data->powernow_table, pstate);
for_each_cpu(i, data->available_cores) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
res = transition_pstate(data, pstate);
freqs.new = find_khz_freq_from_pstate(data->powernow_table, pstate);
for_each_cpu(i, data->available_cores) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
return res;
}
/* Driver entry point to switch to the target frequency */
static int powernowk8_target(struct cpufreq_policy *pol,
unsigned targfreq, unsigned relation)
{
cpumask_var_t oldmask;
struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);
u32 checkfid;
u32 checkvid;
unsigned int newstate;
int ret = -EIO;
if (!data)
return -EINVAL;
checkfid = data->currfid;
checkvid = data->currvid;
/* only run on specific CPU from here on. */
/* This is poor form: use a workqueue or smp_call_function_single */
if (!alloc_cpumask_var(&oldmask, GFP_KERNEL))
return -ENOMEM;
cpumask_copy(oldmask, tsk_cpus_allowed(current));
set_cpus_allowed_ptr(current, cpumask_of(pol->cpu));
if (smp_processor_id() != pol->cpu) {
printk(KERN_ERR PFX "limiting to cpu %u failed\n", pol->cpu);
goto err_out;
}
if (pending_bit_stuck()) {
printk(KERN_ERR PFX "failing targ, change pending bit set\n");
goto err_out;
}
dprintk("targ: cpu %d, %d kHz, min %d, max %d, relation %d\n",
pol->cpu, targfreq, pol->min, pol->max, relation);
if (query_current_values_with_pending_wait(data))
goto err_out;
if (cpu_family != CPU_HW_PSTATE) {
dprintk("targ: curr fid 0x%x, vid 0x%x\n",
data->currfid, data->currvid);
if ((checkvid != data->currvid) ||
(checkfid != data->currfid)) {
printk(KERN_INFO PFX
"error - out of sync, fix 0x%x 0x%x, "
"vid 0x%x 0x%x\n",
checkfid, data->currfid,
checkvid, data->currvid);
}
}
if (cpufreq_frequency_table_target(pol, data->powernow_table,
targfreq, relation, &newstate))
goto err_out;
mutex_lock(&fidvid_mutex);
powernow_k8_acpi_pst_values(data, newstate);
if (cpu_family == CPU_HW_PSTATE)
ret = transition_frequency_pstate(data, newstate);
else
ret = transition_frequency_fidvid(data, newstate);
if (ret) {
printk(KERN_ERR PFX "transition frequency failed\n");
ret = 1;
mutex_unlock(&fidvid_mutex);
goto err_out;
}
mutex_unlock(&fidvid_mutex);
if (cpu_family == CPU_HW_PSTATE)
pol->cur = find_khz_freq_from_pstate(data->powernow_table,
newstate);
else
pol->cur = find_khz_freq_from_fid(data->currfid);
ret = 0;
err_out:
set_cpus_allowed_ptr(current, oldmask);
free_cpumask_var(oldmask);
return ret;
}
/* Driver entry point to verify the policy and range of frequencies */
static int powernowk8_verify(struct cpufreq_policy *pol)
{
struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);
if (!data)
return -EINVAL;
return cpufreq_frequency_table_verify(pol, data->powernow_table);
}
struct init_on_cpu {
struct powernow_k8_data *data;
int rc;
};
static void __cpuinit powernowk8_cpu_init_on_cpu(void *_init_on_cpu)
{
struct init_on_cpu *init_on_cpu = _init_on_cpu;
if (pending_bit_stuck()) {
printk(KERN_ERR PFX "failing init, change pending bit set\n");
init_on_cpu->rc = -ENODEV;
return;
}
if (query_current_values_with_pending_wait(init_on_cpu->data)) {
init_on_cpu->rc = -ENODEV;
return;
}
if (cpu_family == CPU_OPTERON)
fidvid_msr_init();
init_on_cpu->rc = 0;
}
/* per CPU init entry point to the driver */
static int __cpuinit powernowk8_cpu_init(struct cpufreq_policy *pol)
{
static const char ACPI_PSS_BIOS_BUG_MSG[] =
KERN_ERR FW_BUG PFX "No compatible ACPI _PSS objects found.\n"
FW_BUG PFX "Try again with latest BIOS.\n";
struct powernow_k8_data *data;
struct init_on_cpu init_on_cpu;
int rc;
struct cpuinfo_x86 *c = &cpu_data(pol->cpu);
if (!cpu_online(pol->cpu))
return -ENODEV;
smp_call_function_single(pol->cpu, check_supported_cpu, &rc, 1);
if (rc)
return -ENODEV;
data = kzalloc(sizeof(struct powernow_k8_data), GFP_KERNEL);
if (!data) {
printk(KERN_ERR PFX "unable to alloc powernow_k8_data");
return -ENOMEM;
}
data->cpu = pol->cpu;
data->currpstate = HW_PSTATE_INVALID;
if (powernow_k8_cpu_init_acpi(data)) {
/*
* Use the PSB BIOS structure. This is only availabe on
* an UP version, and is deprecated by AMD.
*/
if (num_online_cpus() != 1) {
printk_once(ACPI_PSS_BIOS_BUG_MSG);
goto err_out;
}
if (pol->cpu != 0) {
printk(KERN_ERR FW_BUG PFX "No ACPI _PSS objects for "
"CPU other than CPU0. Complain to your BIOS "
"vendor.\n");
goto err_out;
}
rc = find_psb_table(data);
if (rc)
goto err_out;
/* Take a crude guess here.
* That guess was in microseconds, so multiply with 1000 */
pol->cpuinfo.transition_latency = (
((data->rvo + 8) * data->vstable * VST_UNITS_20US) +
((1 << data->irt) * 30)) * 1000;
} else /* ACPI _PSS objects available */
pol->cpuinfo.transition_latency = get_transition_latency(data);
/* only run on specific CPU from here on */
init_on_cpu.data = data;
smp_call_function_single(data->cpu, powernowk8_cpu_init_on_cpu,
&init_on_cpu, 1);
rc = init_on_cpu.rc;
if (rc != 0)
goto err_out_exit_acpi;
if (cpu_family == CPU_HW_PSTATE)
cpumask_copy(pol->cpus, cpumask_of(pol->cpu));
else
cpumask_copy(pol->cpus, cpu_core_mask(pol->cpu));
data->available_cores = pol->cpus;
if (cpu_family == CPU_HW_PSTATE)
pol->cur = find_khz_freq_from_pstate(data->powernow_table,
data->currpstate);
else
pol->cur = find_khz_freq_from_fid(data->currfid);
dprintk("policy current frequency %d kHz\n", pol->cur);
/* min/max the cpu is capable of */
if (cpufreq_frequency_table_cpuinfo(pol, data->powernow_table)) {
printk(KERN_ERR FW_BUG PFX "invalid powernow_table\n");
powernow_k8_cpu_exit_acpi(data);
kfree(data->powernow_table);
kfree(data);
return -EINVAL;
}
/* Check for APERF/MPERF support in hardware */
if (cpu_has(c, X86_FEATURE_APERFMPERF))
cpufreq_amd64_driver.getavg = cpufreq_get_measured_perf;
cpufreq_frequency_table_get_attr(data->powernow_table, pol->cpu);
if (cpu_family == CPU_HW_PSTATE)
dprintk("cpu_init done, current pstate 0x%x\n",
data->currpstate);
else
dprintk("cpu_init done, current fid 0x%x, vid 0x%x\n",
data->currfid, data->currvid);
per_cpu(powernow_data, pol->cpu) = data;
return 0;
err_out_exit_acpi:
powernow_k8_cpu_exit_acpi(data);
err_out:
kfree(data);
return -ENODEV;
}
static int __devexit powernowk8_cpu_exit(struct cpufreq_policy *pol)
{
struct powernow_k8_data *data = per_cpu(powernow_data, pol->cpu);
if (!data)
return -EINVAL;
powernow_k8_cpu_exit_acpi(data);
cpufreq_frequency_table_put_attr(pol->cpu);
kfree(data->powernow_table);
kfree(data);
per_cpu(powernow_data, pol->cpu) = NULL;
return 0;
}
static void query_values_on_cpu(void *_err)
{
int *err = _err;
struct powernow_k8_data *data = __get_cpu_var(powernow_data);
*err = query_current_values_with_pending_wait(data);
}
static unsigned int powernowk8_get(unsigned int cpu)
{
struct powernow_k8_data *data = per_cpu(powernow_data, cpu);
unsigned int khz = 0;
int err;
if (!data)
return 0;
smp_call_function_single(cpu, query_values_on_cpu, &err, true);
if (err)
goto out;
if (cpu_family == CPU_HW_PSTATE)
khz = find_khz_freq_from_pstate(data->powernow_table,
data->currpstate);
else
khz = find_khz_freq_from_fid(data->currfid);
out:
return khz;
}
static void _cpb_toggle_msrs(bool t)
{
int cpu;
get_online_cpus();
rdmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
for_each_cpu(cpu, cpu_online_mask) {
struct msr *reg = per_cpu_ptr(msrs, cpu);
if (t)
reg->l &= ~BIT(25);
else
reg->l |= BIT(25);
}
wrmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
put_online_cpus();
}
/*
* Switch on/off core performance boosting.
*
* 0=disable
* 1=enable.
*/
static void cpb_toggle(bool t)
{
if (!cpb_capable)
return;
if (t && !cpb_enabled) {
cpb_enabled = true;
_cpb_toggle_msrs(t);
printk(KERN_INFO PFX "Core Boosting enabled.\n");
} else if (!t && cpb_enabled) {
cpb_enabled = false;
_cpb_toggle_msrs(t);
printk(KERN_INFO PFX "Core Boosting disabled.\n");
}
}
static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf,
size_t count)
{
int ret = -EINVAL;
unsigned long val = 0;
ret = strict_strtoul(buf, 10, &val);
if (!ret && (val == 0 || val == 1) && cpb_capable)
cpb_toggle(val);
else
return -EINVAL;
return count;
}
static ssize_t show_cpb(struct cpufreq_policy *policy, char *buf)
{
return sprintf(buf, "%u\n", cpb_enabled);
}
#define define_one_rw(_name) \
static struct freq_attr _name = \
__ATTR(_name, 0644, show_##_name, store_##_name)
define_one_rw(cpb);
static struct freq_attr *powernow_k8_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
&cpb,
NULL,
};
static struct cpufreq_driver cpufreq_amd64_driver = {
.verify = powernowk8_verify,
.target = powernowk8_target,
.bios_limit = acpi_processor_get_bios_limit,
.init = powernowk8_cpu_init,
.exit = __devexit_p(powernowk8_cpu_exit),
.get = powernowk8_get,
.name = "powernow-k8",
.owner = THIS_MODULE,
.attr = powernow_k8_attr,
};
/*
* Clear the boost-disable flag on the CPU_DOWN path so that this cpu
* cannot block the remaining ones from boosting. On the CPU_UP path we
* simply keep the boost-disable flag in sync with the current global
* state.
*/
static int cpb_notify(struct notifier_block *nb, unsigned long action,
void *hcpu)
{
unsigned cpu = (long)hcpu;
u32 lo, hi;
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
if (!cpb_enabled) {
rdmsr_on_cpu(cpu, MSR_K7_HWCR, &lo, &hi);
lo |= BIT(25);
wrmsr_on_cpu(cpu, MSR_K7_HWCR, lo, hi);
}
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
rdmsr_on_cpu(cpu, MSR_K7_HWCR, &lo, &hi);
lo &= ~BIT(25);
wrmsr_on_cpu(cpu, MSR_K7_HWCR, lo, hi);
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block cpb_nb = {
.notifier_call = cpb_notify,
};
/* driver entry point for init */
static int __cpuinit powernowk8_init(void)
{
unsigned int i, supported_cpus = 0, cpu;
for_each_online_cpu(i) {
int rc;
smp_call_function_single(i, check_supported_cpu, &rc, 1);
if (rc == 0)
supported_cpus++;
}
if (supported_cpus != num_online_cpus())
return -ENODEV;
printk(KERN_INFO PFX "Found %d %s (%d cpu cores) (" VERSION ")\n",
num_online_nodes(), boot_cpu_data.x86_model_id, supported_cpus);
if (boot_cpu_has(X86_FEATURE_CPB)) {
cpb_capable = true;
register_cpu_notifier(&cpb_nb);
msrs = msrs_alloc();
if (!msrs) {
printk(KERN_ERR "%s: Error allocating msrs!\n", __func__);
return -ENOMEM;
}
rdmsr_on_cpus(cpu_online_mask, MSR_K7_HWCR, msrs);
for_each_cpu(cpu, cpu_online_mask) {
struct msr *reg = per_cpu_ptr(msrs, cpu);
cpb_enabled |= !(!!(reg->l & BIT(25)));
}
printk(KERN_INFO PFX "Core Performance Boosting: %s.\n",
(cpb_enabled ? "on" : "off"));
}
return cpufreq_register_driver(&cpufreq_amd64_driver);
}
/* driver entry point for term */
static void __exit powernowk8_exit(void)
{
dprintk("exit\n");
if (boot_cpu_has(X86_FEATURE_CPB)) {
msrs_free(msrs);
msrs = NULL;
unregister_cpu_notifier(&cpb_nb);
}
cpufreq_unregister_driver(&cpufreq_amd64_driver);
}
MODULE_AUTHOR("Paul Devriendt <paul.devriendt@amd.com> and "
"Mark Langsdorf <mark.langsdorf@amd.com>");
MODULE_DESCRIPTION("AMD Athlon 64 and Opteron processor frequency driver.");
MODULE_LICENSE("GPL");
late_initcall(powernowk8_init);
module_exit(powernowk8_exit);