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linux/drivers/acpi/processor_throttling.c

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/*
* processor_throttling.c - Throttling submodule of the ACPI processor driver
*
* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
* - Added processor hotplug support
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* 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.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <acpi/acpi_bus.h>
#include <acpi/processor.h>
#define ACPI_PROCESSOR_COMPONENT 0x01000000
#define ACPI_PROCESSOR_CLASS "processor"
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_throttling");
static int acpi_processor_get_throttling(struct acpi_processor *pr);
int acpi_processor_set_throttling(struct acpi_processor *pr, int state);
/*
* _TPC - Throttling Present Capabilities
*/
static int acpi_processor_get_platform_limit(struct acpi_processor *pr)
{
acpi_status status = 0;
unsigned long tpc = 0;
if (!pr)
return -EINVAL;
status = acpi_evaluate_integer(pr->handle, "_TPC", NULL, &tpc);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TPC"));
}
return -ENODEV;
}
pr->throttling_platform_limit = (int)tpc;
return 0;
}
int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
{
return acpi_processor_get_platform_limit(pr);
}
/*
* _PTC - Processor Throttling Control (and status) register location
*/
static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
{
int result = 0;
acpi_status status = 0;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *ptc = NULL;
union acpi_object obj = { 0 };
status = acpi_evaluate_object(pr->handle, "_PTC", NULL, &buffer);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTC"));
}
return -ENODEV;
}
ptc = (union acpi_object *)buffer.pointer;
if (!ptc || (ptc->type != ACPI_TYPE_PACKAGE)
|| (ptc->package.count != 2)) {
printk(KERN_ERR PREFIX "Invalid _PTC data\n");
result = -EFAULT;
goto end;
}
/*
* control_register
*/
obj = ptc->package.elements[0];
if ((obj.type != ACPI_TYPE_BUFFER)
|| (obj.buffer.length < sizeof(struct acpi_ptc_register))
|| (obj.buffer.pointer == NULL)) {
printk(KERN_ERR PREFIX
"Invalid _PTC data (control_register)\n");
result = -EFAULT;
goto end;
}
memcpy(&pr->throttling.control_register, obj.buffer.pointer,
sizeof(struct acpi_ptc_register));
/*
* status_register
*/
obj = ptc->package.elements[1];
if ((obj.type != ACPI_TYPE_BUFFER)
|| (obj.buffer.length < sizeof(struct acpi_ptc_register))
|| (obj.buffer.pointer == NULL)) {
printk(KERN_ERR PREFIX "Invalid _PTC data (status_register)\n");
result = -EFAULT;
goto end;
}
memcpy(&pr->throttling.status_register, obj.buffer.pointer,
sizeof(struct acpi_ptc_register));
end:
kfree(buffer.pointer);
return result;
}
/*
* _TSS - Throttling Supported States
*/
static int acpi_processor_get_throttling_states(struct acpi_processor *pr)
{
int result = 0;
acpi_status status = AE_OK;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
struct acpi_buffer state = { 0, NULL };
union acpi_object *tss = NULL;
int i;
status = acpi_evaluate_object(pr->handle, "_TSS", NULL, &buffer);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSS"));
}
return -ENODEV;
}
tss = buffer.pointer;
if (!tss || (tss->type != ACPI_TYPE_PACKAGE)) {
printk(KERN_ERR PREFIX "Invalid _TSS data\n");
result = -EFAULT;
goto end;
}
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
tss->package.count));
pr->throttling.state_count = tss->package.count;
pr->throttling.states_tss =
kmalloc(sizeof(struct acpi_processor_tx_tss) * tss->package.count,
GFP_KERNEL);
if (!pr->throttling.states_tss) {
result = -ENOMEM;
goto end;
}
for (i = 0; i < pr->throttling.state_count; i++) {
struct acpi_processor_tx_tss *tx =
(struct acpi_processor_tx_tss *)&(pr->throttling.
states_tss[i]);
state.length = sizeof(struct acpi_processor_tx_tss);
state.pointer = tx;
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Extracting state %d\n", i));
status = acpi_extract_package(&(tss->package.elements[i]),
&format, &state);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status, "Invalid _TSS data"));
result = -EFAULT;
kfree(pr->throttling.states_tss);
goto end;
}
if (!tx->freqpercentage) {
printk(KERN_ERR PREFIX
"Invalid _TSS data: freq is zero\n");
result = -EFAULT;
kfree(pr->throttling.states_tss);
goto end;
}
}
end:
kfree(buffer.pointer);
return result;
}
/*
* _TSD - T-State Dependencies
*/
static int acpi_processor_get_tsd(struct acpi_processor *pr)
{
int result = 0;
acpi_status status = AE_OK;
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
struct acpi_buffer format = { sizeof("NNNNN"), "NNNNN" };
struct acpi_buffer state = { 0, NULL };
union acpi_object *tsd = NULL;
struct acpi_tsd_package *pdomain;
status = acpi_evaluate_object(pr->handle, "_TSD", NULL, &buffer);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
ACPI_EXCEPTION((AE_INFO, status, "Evaluating _TSD"));
}
return -ENODEV;
}
tsd = buffer.pointer;
if (!tsd || (tsd->type != ACPI_TYPE_PACKAGE)) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
result = -EFAULT;
goto end;
}
if (tsd->package.count != 1) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
result = -EFAULT;
goto end;
}
pdomain = &(pr->throttling.domain_info);
state.length = sizeof(struct acpi_tsd_package);
state.pointer = pdomain;
status = acpi_extract_package(&(tsd->package.elements[0]),
&format, &state);
if (ACPI_FAILURE(status)) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid _TSD data\n"));
result = -EFAULT;
goto end;
}
if (pdomain->num_entries != ACPI_TSD_REV0_ENTRIES) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:num_entries\n"));
result = -EFAULT;
goto end;
}
if (pdomain->revision != ACPI_TSD_REV0_REVISION) {
ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unknown _TSD:revision\n"));
result = -EFAULT;
goto end;
}
end:
kfree(buffer.pointer);
return result;
}
/* --------------------------------------------------------------------------
Throttling Control
-------------------------------------------------------------------------- */
static int acpi_processor_get_throttling_fadt(struct acpi_processor *pr)
{
int state = 0;
u32 value = 0;
u32 duty_mask = 0;
u32 duty_value = 0;
if (!pr)
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
pr->throttling.state = 0;
duty_mask = pr->throttling.state_count - 1;
duty_mask <<= pr->throttling.duty_offset;
local_irq_disable();
value = inl(pr->throttling.address);
/*
* Compute the current throttling state when throttling is enabled
* (bit 4 is on).
*/
if (value & 0x10) {
duty_value = value & duty_mask;
duty_value >>= pr->throttling.duty_offset;
if (duty_value)
state = pr->throttling.state_count - duty_value;
}
pr->throttling.state = state;
local_irq_enable();
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Throttling state is T%d (%d%% throttling applied)\n",
state, pr->throttling.states[state].performance));
return 0;
}
static int acpi_read_throttling_status(struct acpi_processor_throttling
*throttling)
{
int value = -1;
switch (throttling->status_register.space_id) {
case ACPI_ADR_SPACE_SYSTEM_IO:
acpi_os_read_port((acpi_io_address) throttling->status_register.
address, &value,
(u32) throttling->status_register.bit_width *
8);
break;
case ACPI_ADR_SPACE_FIXED_HARDWARE:
printk(KERN_ERR PREFIX
"HARDWARE addr space,NOT supported yet\n");
break;
default:
printk(KERN_ERR PREFIX "Unknown addr space %d\n",
(u32) (throttling->status_register.space_id));
}
return value;
}
static int acpi_write_throttling_state(struct acpi_processor_throttling
*throttling, int value)
{
int ret = -1;
switch (throttling->control_register.space_id) {
case ACPI_ADR_SPACE_SYSTEM_IO:
acpi_os_write_port((acpi_io_address) throttling->
control_register.address, value,
(u32) throttling->control_register.
bit_width * 8);
ret = 0;
break;
case ACPI_ADR_SPACE_FIXED_HARDWARE:
printk(KERN_ERR PREFIX
"HARDWARE addr space,NOT supported yet\n");
break;
default:
printk(KERN_ERR PREFIX "Unknown addr space %d\n",
(u32) (throttling->control_register.space_id));
}
return ret;
}
static int acpi_get_throttling_state(struct acpi_processor *pr, int value)
{
int i;
for (i = 0; i < pr->throttling.state_count; i++) {
struct acpi_processor_tx_tss *tx =
(struct acpi_processor_tx_tss *)&(pr->throttling.
states_tss[i]);
if (tx->control == value)
break;
}
if (i > pr->throttling.state_count)
i = -1;
return i;
}
static int acpi_get_throttling_value(struct acpi_processor *pr, int state)
{
int value = -1;
if (state >= 0 && state <= pr->throttling.state_count) {
struct acpi_processor_tx_tss *tx =
(struct acpi_processor_tx_tss *)&(pr->throttling.
states_tss[state]);
value = tx->control;
}
return value;
}
static int acpi_processor_get_throttling_ptc(struct acpi_processor *pr)
{
int state = 0;
u32 value = 0;
if (!pr)
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
pr->throttling.state = 0;
local_irq_disable();
value = acpi_read_throttling_status(&pr->throttling);
if (value >= 0) {
state = acpi_get_throttling_state(pr, value);
pr->throttling.state = state;
}
local_irq_enable();
return 0;
}
static int acpi_processor_get_throttling(struct acpi_processor *pr)
{
return pr->throttling.acpi_processor_get_throttling(pr);
}
static int acpi_processor_set_throttling_fadt(struct acpi_processor *pr,
int state)
{
u32 value = 0;
u32 duty_mask = 0;
u32 duty_value = 0;
if (!pr)
return -EINVAL;
if ((state < 0) || (state > (pr->throttling.state_count - 1)))
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
if (state == pr->throttling.state)
return 0;
if (state < pr->throttling_platform_limit)
return -EPERM;
/*
* Calculate the duty_value and duty_mask.
*/
if (state) {
duty_value = pr->throttling.state_count - state;
duty_value <<= pr->throttling.duty_offset;
/* Used to clear all duty_value bits */
duty_mask = pr->throttling.state_count - 1;
duty_mask <<= acpi_gbl_FADT.duty_offset;
duty_mask = ~duty_mask;
}
local_irq_disable();
/*
* Disable throttling by writing a 0 to bit 4. Note that we must
* turn it off before you can change the duty_value.
*/
value = inl(pr->throttling.address);
if (value & 0x10) {
value &= 0xFFFFFFEF;
outl(value, pr->throttling.address);
}
/*
* Write the new duty_value and then enable throttling. Note
* that a state value of 0 leaves throttling disabled.
*/
if (state) {
value &= duty_mask;
value |= duty_value;
outl(value, pr->throttling.address);
value |= 0x00000010;
outl(value, pr->throttling.address);
}
pr->throttling.state = state;
local_irq_enable();
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Throttling state set to T%d (%d%%)\n", state,
(pr->throttling.states[state].performance ? pr->
throttling.states[state].performance / 10 : 0)));
return 0;
}
static int acpi_processor_set_throttling_ptc(struct acpi_processor *pr,
int state)
{
u32 value = 0;
if (!pr)
return -EINVAL;
if ((state < 0) || (state > (pr->throttling.state_count - 1)))
return -EINVAL;
if (!pr->flags.throttling)
return -ENODEV;
if (state == pr->throttling.state)
return 0;
if (state < pr->throttling_platform_limit)
return -EPERM;
local_irq_disable();
value = acpi_get_throttling_value(pr, state);
if (value >= 0) {
acpi_write_throttling_state(&pr->throttling, value);
pr->throttling.state = state;
}
local_irq_enable();
return 0;
}
int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
{
return pr->throttling.acpi_processor_set_throttling(pr, state);
}
int acpi_processor_get_throttling_info(struct acpi_processor *pr)
{
int result = 0;
int step = 0;
int i = 0;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n",
pr->throttling.address,
pr->throttling.duty_offset,
pr->throttling.duty_width));
if (!pr)
return -EINVAL;
/*
* Evaluate _PTC, _TSS and _TPC
* They must all be present or none of them can be used.
*/
if (acpi_processor_get_throttling_control(pr) ||
acpi_processor_get_throttling_states(pr) ||
acpi_processor_get_platform_limit(pr))
{
pr->throttling.acpi_processor_get_throttling =
&acpi_processor_get_throttling_fadt;
pr->throttling.acpi_processor_set_throttling =
&acpi_processor_set_throttling_fadt;
} else {
pr->throttling.acpi_processor_get_throttling =
&acpi_processor_get_throttling_ptc;
pr->throttling.acpi_processor_set_throttling =
&acpi_processor_set_throttling_ptc;
}
acpi_processor_get_tsd(pr);
if (!pr->throttling.address) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n"));
return 0;
} else if (!pr->throttling.duty_width) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n"));
return 0;
}
/* TBD: Support duty_cycle values that span bit 4. */
else if ((pr->throttling.duty_offset + pr->throttling.duty_width) > 4) {
printk(KERN_WARNING PREFIX "duty_cycle spans bit 4\n");
return 0;
}
/*
* PIIX4 Errata: We don't support throttling on the original PIIX4.
* This shouldn't be an issue as few (if any) mobile systems ever
* used this part.
*/
if (errata.piix4.throttle) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Throttling not supported on PIIX4 A- or B-step\n"));
return 0;
}
pr->throttling.state_count = 1 << acpi_gbl_FADT.duty_width;
/*
* Compute state values. Note that throttling displays a linear power/
* performance relationship (at 50% performance the CPU will consume
* 50% power). Values are in 1/10th of a percent to preserve accuracy.
*/
step = (1000 / pr->throttling.state_count);
for (i = 0; i < pr->throttling.state_count; i++) {
pr->throttling.states[i].performance = step * i;
pr->throttling.states[i].power = step * i;
}
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n",
pr->throttling.state_count));
pr->flags.throttling = 1;
/*
* Disable throttling (if enabled). We'll let subsequent policy (e.g.
* thermal) decide to lower performance if it so chooses, but for now
* we'll crank up the speed.
*/
result = acpi_processor_get_throttling(pr);
if (result)
goto end;
if (pr->throttling.state) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Disabling throttling (was T%d)\n",
pr->throttling.state));
result = acpi_processor_set_throttling(pr, 0);
if (result)
goto end;
}
end:
if (result)
pr->flags.throttling = 0;
return result;
}
/* proc interface */
static int acpi_processor_throttling_seq_show(struct seq_file *seq,
void *offset)
{
struct acpi_processor *pr = seq->private;
int i = 0;
int result = 0;
if (!pr)
goto end;
if (!(pr->throttling.state_count > 0)) {
seq_puts(seq, "<not supported>\n");
goto end;
}
result = acpi_processor_get_throttling(pr);
if (result) {
seq_puts(seq,
"Could not determine current throttling state.\n");
goto end;
}
seq_printf(seq, "state count: %d\n"
"active state: T%d\n"
"state available: T%d to T%d\n",
pr->throttling.state_count, pr->throttling.state,
pr->throttling_platform_limit,
pr->throttling.state_count - 1);
seq_puts(seq, "states:\n");
if (pr->throttling.acpi_processor_get_throttling ==
acpi_processor_get_throttling_fadt) {
for (i = 0; i < pr->throttling.state_count; i++)
seq_printf(seq, " %cT%d: %02d%%\n",
(i == pr->throttling.state ? '*' : ' '), i,
(pr->throttling.states[i].performance ? pr->
throttling.states[i].performance / 10 : 0));
} else {
for (i = 0; i < pr->throttling.state_count; i++)
seq_printf(seq, " %cT%d: %02d%%\n",
(i == pr->throttling.state ? '*' : ' '), i,
(int)pr->throttling.states_tss[i].
freqpercentage);
}
end:
return 0;
}
static int acpi_processor_throttling_open_fs(struct inode *inode,
struct file *file)
{
return single_open(file, acpi_processor_throttling_seq_show,
PDE(inode)->data);
}
static ssize_t acpi_processor_write_throttling(struct file *file,
const char __user * buffer,
size_t count, loff_t * data)
{
int result = 0;
struct seq_file *m = file->private_data;
struct acpi_processor *pr = m->private;
char state_string[12] = { '\0' };
if (!pr || (count > sizeof(state_string) - 1))
return -EINVAL;
if (copy_from_user(state_string, buffer, count))
return -EFAULT;
state_string[count] = '\0';
result = acpi_processor_set_throttling(pr,
simple_strtoul(state_string,
NULL, 0));
if (result)
return result;
return count;
}
struct file_operations acpi_processor_throttling_fops = {
.open = acpi_processor_throttling_open_fs,
.read = seq_read,
.write = acpi_processor_write_throttling,
.llseek = seq_lseek,
.release = single_release,
};
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