linux/drivers/cpufreq/speedstep-smi.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Intel SpeedStep SMI driver.
*
* (C) 2003 Hiroshi Miura <miura@da-cha.org>
*/
/*********************************************************************
* SPEEDSTEP - DEFINITIONS *
*********************************************************************/
#define pr_fmt(fmt) "cpufreq: " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <asm/ist.h>
#include <asm/cpu_device_id.h>
#include "speedstep-lib.h"
/* speedstep system management interface port/command.
*
* These parameters are got from IST-SMI BIOS call.
* If user gives it, these are used.
*
*/
static int smi_port;
static int smi_cmd;
static unsigned int smi_sig;
/* info about the processor */
static enum speedstep_processor speedstep_processor;
/*
* There are only two frequency states for each processor. Values
* are in kHz for the time being.
*/
static struct cpufreq_frequency_table speedstep_freqs[] = {
{0, SPEEDSTEP_HIGH, 0},
{0, SPEEDSTEP_LOW, 0},
{0, 0, CPUFREQ_TABLE_END},
};
#define GET_SPEEDSTEP_OWNER 0
#define GET_SPEEDSTEP_STATE 1
#define SET_SPEEDSTEP_STATE 2
#define GET_SPEEDSTEP_FREQS 4
/* how often shall the SMI call be tried if it failed, e.g. because
* of DMA activity going on? */
#define SMI_TRIES 5
/**
* speedstep_smi_ownership
*/
static int speedstep_smi_ownership(void)
{
u32 command, result, magic, dummy;
u32 function = GET_SPEEDSTEP_OWNER;
unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
magic = virt_to_phys(magic_data);
pr_debug("trying to obtain ownership with command %x at port %x\n",
command, smi_port);
__asm__ __volatile__(
"push %%ebp\n"
"out %%al, (%%dx)\n"
"pop %%ebp\n"
: "=D" (result),
"=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
"=S" (dummy)
: "a" (command), "b" (function), "c" (0), "d" (smi_port),
"D" (0), "S" (magic)
: "memory"
);
pr_debug("result is %x\n", result);
return result;
}
/**
* speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
* @low: the low frequency value is placed here
* @high: the high frequency value is placed here
*
* Only available on later SpeedStep-enabled systems, returns false results or
* even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
* shows that the latter occurs if !(ist_info.event & 0xFFFF).
*/
static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high)
{
u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
u32 state = 0;
u32 function = GET_SPEEDSTEP_FREQS;
if (!(ist_info.event & 0xFFFF)) {
pr_debug("bug #1422 -- can't read freqs from BIOS\n");
return -ENODEV;
}
command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
pr_debug("trying to determine frequencies with command %x at port %x\n",
command, smi_port);
__asm__ __volatile__(
"push %%ebp\n"
"out %%al, (%%dx)\n"
"pop %%ebp"
: "=a" (result),
"=b" (high_mhz),
"=c" (low_mhz),
"=d" (state), "=D" (edi), "=S" (dummy)
: "a" (command),
"b" (function),
"c" (state),
"d" (smi_port), "S" (0), "D" (0)
);
pr_debug("result %x, low_freq %u, high_freq %u\n",
result, low_mhz, high_mhz);
/* abort if results are obviously incorrect... */
if ((high_mhz + low_mhz) < 600)
return -EINVAL;
*high = high_mhz * 1000;
*low = low_mhz * 1000;
return result;
}
/**
* speedstep_set_state - set the SpeedStep state
* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
*
*/
static void speedstep_set_state(unsigned int state)
{
unsigned int result = 0, command, new_state, dummy;
unsigned long flags;
unsigned int function = SET_SPEEDSTEP_STATE;
unsigned int retry = 0;
if (state > 0x1)
return;
/* Disable IRQs */
preempt_disable();
local_irq_save(flags);
command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
pr_debug("trying to set frequency to state %u "
"with command %x at port %x\n",
state, command, smi_port);
do {
if (retry) {
/*
* We need to enable interrupts, otherwise the blockage
* won't resolve.
*
* We disable preemption so that other processes don't
* run. If other processes were running, they could
* submit more DMA requests, making the blockage worse.
*/
pr_debug("retry %u, previous result %u, waiting...\n",
retry, result);
local_irq_enable();
mdelay(retry * 50);
local_irq_disable();
}
retry++;
__asm__ __volatile__(
"push %%ebp\n"
"out %%al, (%%dx)\n"
"pop %%ebp"
: "=b" (new_state), "=D" (result),
"=c" (dummy), "=a" (dummy),
"=d" (dummy), "=S" (dummy)
: "a" (command), "b" (function), "c" (state),
"d" (smi_port), "S" (0), "D" (0)
);
} while ((new_state != state) && (retry <= SMI_TRIES));
/* enable IRQs */
local_irq_restore(flags);
preempt_enable();
if (new_state == state)
pr_debug("change to %u MHz succeeded after %u tries "
"with result %u\n",
(speedstep_freqs[new_state].frequency / 1000),
retry, result);
else
pr_err("change to state %u failed with new_state %u and result %u\n",
state, new_state, result);
return;
}
/**
* speedstep_target - set a new CPUFreq policy
* @policy: new policy
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:15:48 +08:00
* @index: index of new freq
*
* Sets a new CPUFreq policy/freq.
*/
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:15:48 +08:00
static int speedstep_target(struct cpufreq_policy *policy, unsigned int index)
{
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:15:48 +08:00
speedstep_set_state(index);
return 0;
}
static int speedstep_cpu_init(struct cpufreq_policy *policy)
{
int result;
unsigned int *low, *high;
/* capability check */
if (policy->cpu != 0)
return -ENODEV;
result = speedstep_smi_ownership();
if (result) {
pr_debug("fails in acquiring ownership of a SMI interface.\n");
return -EINVAL;
}
/* detect low and high frequency */
low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
result = speedstep_smi_get_freqs(low, high);
if (result) {
/* fall back to speedstep_lib.c dection mechanism:
* try both states out */
pr_debug("could not detect low and high frequencies "
"by SMI call.\n");
result = speedstep_get_freqs(speedstep_processor,
low, high,
NULL,
&speedstep_set_state);
if (result) {
pr_debug("could not detect two different speeds"
" -- aborting.\n");
return result;
} else
pr_debug("workaround worked.\n");
}
policy->freq_table = speedstep_freqs;
return 0;
}
static unsigned int speedstep_get(unsigned int cpu)
{
if (cpu)
return -ENODEV;
return speedstep_get_frequency(speedstep_processor);
}
static int speedstep_resume(struct cpufreq_policy *policy)
{
int result = speedstep_smi_ownership();
if (result)
pr_debug("fails in re-acquiring ownership of a SMI interface.\n");
return result;
}
static struct cpufreq_driver speedstep_driver = {
.name = "speedstep-smi",
.flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
.verify = cpufreq_generic_frequency_table_verify,
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:15:48 +08:00
.target_index = speedstep_target,
.init = speedstep_cpu_init,
.get = speedstep_get,
.resume = speedstep_resume,
.attr = cpufreq_generic_attr,
};
static const struct x86_cpu_id ss_smi_ids[] = {
{ X86_VENDOR_INTEL, 6, 0xb, },
{ X86_VENDOR_INTEL, 6, 0x8, },
{ X86_VENDOR_INTEL, 15, 2 },
{}
};
#if 0
/* Not auto loaded currently */
MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
#endif
/**
* speedstep_init - initializes the SpeedStep CPUFreq driver
*
* Initializes the SpeedStep support. Returns -ENODEV on unsupported
* BIOS, -EINVAL on problems during initiatization, and zero on
* success.
*/
static int __init speedstep_init(void)
{
if (!x86_match_cpu(ss_smi_ids))
return -ENODEV;
speedstep_processor = speedstep_detect_processor();
switch (speedstep_processor) {
case SPEEDSTEP_CPU_PIII_T:
case SPEEDSTEP_CPU_PIII_C:
case SPEEDSTEP_CPU_PIII_C_EARLY:
break;
default:
speedstep_processor = 0;
}
if (!speedstep_processor) {
pr_debug("No supported Intel CPU detected.\n");
return -ENODEV;
}
pr_debug("signature:0x%.8x, command:0x%.8x, "
"event:0x%.8x, perf_level:0x%.8x.\n",
ist_info.signature, ist_info.command,
ist_info.event, ist_info.perf_level);
/* Error if no IST-SMI BIOS or no PARM
sig= 'ISGE' aka 'Intel Speedstep Gate E' */
if ((ist_info.signature != 0x47534943) && (
(smi_port == 0) || (smi_cmd == 0)))
return -ENODEV;
if (smi_sig == 1)
smi_sig = 0x47534943;
else
smi_sig = ist_info.signature;
/* setup smi_port from MODLULE_PARM or BIOS */
if ((smi_port > 0xff) || (smi_port < 0))
return -EINVAL;
else if (smi_port == 0)
smi_port = ist_info.command & 0xff;
if ((smi_cmd > 0xff) || (smi_cmd < 0))
return -EINVAL;
else if (smi_cmd == 0)
smi_cmd = (ist_info.command >> 16) & 0xff;
return cpufreq_register_driver(&speedstep_driver);
}
/**
* speedstep_exit - unregisters SpeedStep support
*
* Unregisters SpeedStep support.
*/
static void __exit speedstep_exit(void)
{
cpufreq_unregister_driver(&speedstep_driver);
}
module_param_hw(smi_port, int, ioport, 0444);
module_param(smi_cmd, int, 0444);
module_param(smi_sig, uint, 0444);
MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
"-- Intel's default setting is 0xb2");
MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
"-- Intel's default setting is 0x82");
MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
"SMI interface.");
MODULE_AUTHOR("Hiroshi Miura");
MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
MODULE_LICENSE("GPL");
module_init(speedstep_init);
module_exit(speedstep_exit);