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linux/drivers/cpufreq/powernow-k7.c
Srivatsa S. Bhat 8997b18511 cpufreq: powernow-k7: Fix double invocation of cpufreq_freq_transition_begin/end 
During frequency transitions, the cpufreq core takes the responsibility of
invoking cpufreq_freq_transition_begin() and cpufreq_freq_transition_end()
for those cpufreq drivers that define the ->target_index callback but don't
set the ASYNC_NOTIFICATION flag.

The powernow-k7 cpufreq driver falls under this category, but this driver was
invoking the _begin() and _end() APIs itself around frequency transitions,
which led to double invocation of the _begin() API. The _begin API makes
contending callers wait until the previous invocation is complete. Hence,
the powernow-k7 driver ended up waiting on itself, leading to system hangs
during boot.

Fix this by removing the calls to the _begin() and _end() APIs from the
powernow-k7 driver, since they rightly belong to the cpufreq core.

Fixes: 12478cf0c5 (cpufreq: Make sure frequency transitions are serialized)
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-04-29 01:22:54 +02:00

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/*
* AMD K7 Powernow driver.
* (C) 2003 Dave Jones on behalf of SuSE Labs.
* (C) 2003-2004 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.
*
* Errata 5:
* CPU 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:
* CPU with half frequency multipliers may hang upon wakeup from disconnect.
* - We disable half multipliers if ACPI is used on A0 stepping CPUs.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/dmi.h>
#include <linux/timex.h>
#include <linux/io.h>
#include <asm/timer.h> /* Needed for recalibrate_cpu_khz() */
#include <asm/msr.h>
#include <asm/cpu_device_id.h>
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
#include <linux/acpi.h>
#include <acpi/processor.h>
#endif
#include "powernow-k7.h"
#define PFX "powernow: "
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;
};
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
union powernow_acpi_control_t {
struct {
unsigned long fid:5,
vid:5,
sgtc:20,
res1:2;
} bits;
unsigned long val;
};
#endif
/* divide by 1000 to get VCore voltage in V. */
static const 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, 1025, 1000, 975, 950, 925, 0,
};
/* divide by 10 to get FID. */
static const 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,
};
/* This parameter is used in order to force ACPI instead of legacy method for
* configuration purpose.
*/
static int acpi_force;
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_fsb(unsigned int fsbspeed)
{
int delta;
unsigned int f = fsb / 1000;
delta = (fsbspeed > f) ? fsbspeed - f : f - fsbspeed;
return delta < 5;
}
static const struct x86_cpu_id powernow_k7_cpuids[] = {
{ X86_VENDOR_AMD, 6, },
{}
};
MODULE_DEVICE_TABLE(x86cpu, powernow_k7_cpuids);
static int check_powernow(void)
{
struct cpuinfo_x86 *c = &cpu_data(0);
unsigned int maxei, eax, ebx, ecx, edx;
if (!x86_match_cpu(powernow_k7_cpuids))
return 0;
/* Get maximum capabilities */
maxei = cpuid_eax(0x80000000);
if (maxei < 0x80000007) { /* Any powernow info ? */
#ifdef MODULE
printk(KERN_INFO PFX "No powernow capabilities detected\n");
#endif
return 0;
}
if ((c->x86_model == 6) && (c->x86_mask == 0)) {
printk(KERN_INFO PFX "K7 660[A0] core detected, "
"enabling errata workarounds\n");
have_a0 = 1;
}
cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
/* Check we can actually do something before we say anything.*/
if (!(edx & (1 << 1 | 1 << 2)))
return 0;
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;
}
printk(".\n");
return 1;
}
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
static void invalidate_entry(unsigned int entry)
{
powernow_table[entry].frequency = CPUFREQ_ENTRY_INVALID;
}
#endif
static int get_ranges(unsigned char *pst)
{
unsigned int j;
unsigned int speed;
u8 fid, vid;
powernow_table = kzalloc((sizeof(*powernow_table) *
(number_scales + 1)), GFP_KERNEL);
if (!powernow_table)
return -ENOMEM;
for (j = 0 ; j < number_scales; j++) {
fid = *pst++;
powernow_table[j].frequency = (fsb * fid_codes[fid]) / 10;
powernow_table[j].driver_data = fid; /* lower 8 bits */
speed = powernow_table[j].frequency;
if ((fid_codes[fid] % 10) == 5) {
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
if (have_a0 == 1)
invalidate_entry(j);
#endif
}
if (speed < minimum_speed)
minimum_speed = speed;
if (speed > maximum_speed)
maximum_speed = speed;
vid = *pst++;
powernow_table[j].driver_data |= (vid << 8); /* upper 8 bits */
pr_debug(" FID: 0x%x (%d.%dx [%dMHz]) "
"VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
fid_codes[fid] % 10, speed/1000, vid,
mobile_vid_table[vid]/1000,
mobile_vid_table[vid]%1000);
}
powernow_table[number_scales].frequency = CPUFREQ_TABLE_END;
powernow_table[number_scales].driver_data = 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 int powernow_target(struct cpufreq_policy *policy, 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].driver_data & 0xFF;
vid = (powernow_table[index].driver_data & 0xFF00) >> 8;
rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
cfid = fidvidstatus.bits.CFID;
freqs.old = fsb * fid_codes[cfid] / 10;
freqs.new = powernow_table[index].frequency;
/* 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();
return 0;
}
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
static struct acpi_processor_performance *acpi_processor_perf;
static int powernow_acpi_init(void)
{
int i;
int retval = 0;
union powernow_acpi_control_t pc;
if (acpi_processor_perf != NULL && powernow_table != NULL) {
retval = -EINVAL;
goto err0;
}
acpi_processor_perf = kzalloc(sizeof(*acpi_processor_perf), GFP_KERNEL);
if (!acpi_processor_perf) {
retval = -ENOMEM;
goto err0;
}
if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
GFP_KERNEL)) {
retval = -ENOMEM;
goto err05;
}
if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
retval = -EIO;
goto err1;
}
if (acpi_processor_perf->control_register.space_id !=
ACPI_ADR_SPACE_FIXED_HARDWARE) {
retval = -ENODEV;
goto err2;
}
if (acpi_processor_perf->status_register.space_id !=
ACPI_ADR_SPACE_FIXED_HARDWARE) {
retval = -ENODEV;
goto err2;
}
number_scales = acpi_processor_perf->state_count;
if (number_scales < 2) {
retval = -ENODEV;
goto err2;
}
powernow_table = kzalloc((sizeof(*powernow_table) *
(number_scales + 1)), GFP_KERNEL);
if (!powernow_table) {
retval = -ENOMEM;
goto err2;
}
pc.val = (unsigned long) acpi_processor_perf->states[0].control;
for (i = 0; i < number_scales; i++) {
u8 fid, vid;
struct acpi_processor_px *state =
&acpi_processor_perf->states[i];
unsigned int speed, speed_mhz;
pc.val = (unsigned long) state->control;
pr_debug("acpi: P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
i,
(u32) state->core_frequency,
(u32) state->power,
(u32) state->transition_latency,
(u32) state->control,
pc.bits.sgtc);
vid = pc.bits.vid;
fid = pc.bits.fid;
powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
powernow_table[i].driver_data = fid; /* lower 8 bits */
powernow_table[i].driver_data |= (vid << 8); /* upper 8 bits */
speed = powernow_table[i].frequency;
speed_mhz = speed / 1000;
/* processor_perflib will multiply the MHz value by 1000 to
* get a KHz value (e.g. 1266000). However, powernow-k7 works
* with true KHz values (e.g. 1266768). To ensure that all
* powernow frequencies are available, we must ensure that
* ACPI doesn't restrict them, so we round up the MHz value
* to ensure that perflib's computed KHz value is greater than
* or equal to powernow's KHz value.
*/
if (speed % 1000 > 0)
speed_mhz++;
if ((fid_codes[fid] % 10) == 5) {
if (have_a0 == 1)
invalidate_entry(i);
}
pr_debug(" FID: 0x%x (%d.%dx [%dMHz]) "
"VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
fid_codes[fid] % 10, speed_mhz, vid,
mobile_vid_table[vid]/1000,
mobile_vid_table[vid]%1000);
if (state->core_frequency != speed_mhz) {
state->core_frequency = speed_mhz;
pr_debug(" Corrected ACPI frequency to %d\n",
speed_mhz);
}
if (latency < pc.bits.sgtc)
latency = pc.bits.sgtc;
if (speed < minimum_speed)
minimum_speed = speed;
if (speed > maximum_speed)
maximum_speed = speed;
}
powernow_table[i].frequency = CPUFREQ_TABLE_END;
powernow_table[i].driver_data = 0;
/* notify BIOS that we exist */
acpi_processor_notify_smm(THIS_MODULE);
return 0;
err2:
acpi_processor_unregister_performance(acpi_processor_perf, 0);
err1:
free_cpumask_var(acpi_processor_perf->shared_cpu_map);
err05:
kfree(acpi_processor_perf);
err0:
printk(KERN_WARNING PFX "ACPI perflib can not be used on "
"this platform\n");
acpi_processor_perf = NULL;
return retval;
}
#else
static int powernow_acpi_init(void)
{
printk(KERN_INFO PFX "no support for ACPI processor found."
" Please recompile your kernel with ACPI processor\n");
return -EINVAL;
}
#endif
static void print_pst_entry(struct pst_s *pst, unsigned int j)
{
pr_debug("PST:%d (@%p)\n", j, pst);
pr_debug(" cpuid: 0x%x fsb: %d maxFID: 0x%x startvid: 0x%x\n",
pst->cpuid, pst->fsbspeed, pst->maxfid, pst->startvid);
}
static int powernow_decode_bios(int maxfid, int startvid)
{
struct psb_s *psb;
struct pst_s *pst;
unsigned int i, j;
unsigned char *p;
unsigned int etuple;
unsigned int ret;
etuple = cpuid_eax(0x80000001);
for (i = 0xC0000; i < 0xffff0 ; i += 16) {
p = phys_to_virt(i);
if (memcmp(p, "AMDK7PNOW!", 10) == 0) {
pr_debug("Found PSB header at %p\n", p);
psb = (struct psb_s *) p;
pr_debug("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;
}
pr_debug("Flags: 0x%x\n", psb->flags);
if ((psb->flags & 1) == 0)
pr_debug("Mobile voltage regulator\n");
else
pr_debug("Desktop 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;
}
pr_debug("Settling Time: %d microseconds.\n",
psb->settlingtime);
pr_debug("Has %d PST tables. (Only dumping ones "
"relevant to this CPU).\n",
psb->numpst);
p += sizeof(*psb);
pst = (struct pst_s *) p;
for (j = 0; j < psb->numpst; j++) {
pst = (struct pst_s *) p;
number_scales = pst->numpstates;
if ((etuple == pst->cpuid) &&
check_fsb(pst->fsbspeed) &&
(maxfid == pst->maxfid) &&
(startvid == pst->startvid)) {
print_pst_entry(pst, j);
p = (char *)pst + sizeof(*pst);
ret = get_ranges(p);
return ret;
} else {
unsigned int k;
p = (char *)pst + sizeof(*pst);
for (k = 0; k < number_scales; k++)
p += 2;
}
}
printk(KERN_INFO PFX "No PST tables match this cpuid "
"(0x%x)\n", etuple);
printk(KERN_INFO PFX "This is indicative of a broken "
"BIOS.\n");
return -EINVAL;
}
p++;
}
return -ENODEV;
}
/*
* We use the fact that the bus frequency is somehow
* a multiple of 100000/3 khz, then we compute sgtc according
* to this multiple.
* That way, we match more how AMD thinks all of that work.
* We will then get the same kind of behaviour already tested under
* the "well-known" other OS.
*/
static int fixup_sgtc(void)
{
unsigned int sgtc;
unsigned int m;
m = fsb / 3333;
if ((m % 10) >= 5)
m += 5;
m /= 10;
sgtc = 100 * m * latency;
sgtc = sgtc / 3;
if (sgtc > 0xfffff) {
printk(KERN_WARNING PFX "SGTC too large %d\n", sgtc);
sgtc = 0xfffff;
}
return sgtc;
}
static unsigned int powernow_get(unsigned int cpu)
{
union msr_fidvidstatus fidvidstatus;
unsigned int cfid;
if (cpu)
return 0;
rdmsrl(MSR_K7_FID_VID_STATUS, fidvidstatus.val);
cfid = fidvidstatus.bits.CFID;
return fsb * fid_codes[cfid] / 10;
}
static int acer_cpufreq_pst(const struct dmi_system_id *d)
{
printk(KERN_WARNING PFX
"%s laptop with broken PST tables in BIOS detected.\n",
d->ident);
printk(KERN_WARNING PFX
"You need to downgrade to 3A21 (09/09/2002), or try a newer "
"BIOS than 3A71 (01/20/2003)\n");
printk(KERN_WARNING PFX
"cpufreq scaling has been disabled as a result of this.\n");
return 0;
}
/*
* Some Athlon laptops have really fucked PST tables.
* A BIOS update is all that can save them.
* Mention this, and disable cpufreq.
*/
static struct dmi_system_id powernow_dmi_table[] = {
{
.callback = acer_cpufreq_pst,
.ident = "Acer Aspire",
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Insyde Software"),
DMI_MATCH(DMI_BIOS_VERSION, "3A71"),
},
},
{ }
};
static int 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);
recalibrate_cpu_khz();
fsb = (10 * cpu_khz) / fid_codes[fidvidstatus.bits.CFID];
if (!fsb) {
printk(KERN_WARNING PFX "can not determine bus frequency\n");
return -EINVAL;
}
pr_debug("FSB: %3dMHz\n", fsb/1000);
if (dmi_check_system(powernow_dmi_table) || acpi_force) {
printk(KERN_INFO PFX "PSB/PST known to be broken. "
"Trying ACPI instead\n");
result = powernow_acpi_init();
} else {
result = powernow_decode_bios(fidvidstatus.bits.MFID,
fidvidstatus.bits.SVID);
if (result) {
printk(KERN_INFO PFX "Trying ACPI perflib\n");
maximum_speed = 0;
minimum_speed = -1;
latency = 0;
result = powernow_acpi_init();
if (result) {
printk(KERN_INFO PFX
"ACPI and legacy methods failed\n");
}
} else {
/* SGTC use the bus clock as timer */
latency = fixup_sgtc();
printk(KERN_INFO PFX "SGTC: %d\n", latency);
}
}
if (result)
return result;
printk(KERN_INFO PFX "Minimum speed %d MHz. Maximum speed %d MHz.\n",
minimum_speed/1000, maximum_speed/1000);
policy->cpuinfo.transition_latency =
cpufreq_scale(2000000UL, fsb, latency);
return cpufreq_table_validate_and_show(policy, powernow_table);
}
static int powernow_cpu_exit(struct cpufreq_policy *policy)
{
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
if (acpi_processor_perf) {
acpi_processor_unregister_performance(acpi_processor_perf, 0);
free_cpumask_var(acpi_processor_perf->shared_cpu_map);
kfree(acpi_processor_perf);
}
#endif
kfree(powernow_table);
return 0;
}
static struct cpufreq_driver powernow_driver = {
.verify = cpufreq_generic_frequency_table_verify,
.target_index = powernow_target,
.get = powernow_get,
#ifdef CONFIG_X86_POWERNOW_K7_ACPI
.bios_limit = acpi_processor_get_bios_limit,
#endif
.init = powernow_cpu_init,
.exit = powernow_cpu_exit,
.name = "powernow-k7",
.attr = cpufreq_generic_attr,
};
static int __init powernow_init(void)
{
if (check_powernow() == 0)
return -ENODEV;
return cpufreq_register_driver(&powernow_driver);
}
static void __exit powernow_exit(void)
{
cpufreq_unregister_driver(&powernow_driver);
}
module_param(acpi_force, int, 0444);
MODULE_PARM_DESC(acpi_force, "Force ACPI to be used.");
MODULE_AUTHOR("Dave Jones <davej@redhat.com>");
MODULE_DESCRIPTION("Powernow driver for AMD K7 processors.");
MODULE_LICENSE("GPL");
late_initcall(powernow_init);
module_exit(powernow_exit);
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