Commit 37afb000 authored by Srinivas Pandruvada's avatar Srinivas Pandruvada Committed by Rafael J. Wysocki
Browse files

cpufreq: intel_pstate: Use ACPI perf configuration 



Use ACPI _PSS to limit the Intel P State turbo, max and min ratios.
This driver uses acpi processor perf lib calls to register performance.
The following logic is used to adjust Intel P state driver limits:
- If there is no turbo entry in _PSS, then disable Intel P state turbo
and limit to non turbo max
- If the non turbo max ratio is more than _PSS max non turbo value, then
set the max non turbo ratio to _PSS non turbo max
- If the min ratio is less than _PSS min then change the min ratio
matching _PSS min
- Scale the _PSS turbo frequency to max turbo frequency based on control
value.
This feature can be disabled by using kernel parameters:
intel_pstate=no_acpi

Signed-off-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: default avatarKristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 3bcc6fa9

drivers/cpufreq/Kconfig.x86

+1 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
config X86_INTEL_PSTATE

       bool "Intel P state control"

       depends on X86

       select ACPI_PROCESSOR if ACPI

       help

          This driver provides a P state for Intel core processors.

	  The driver implements an internal governor and will become

drivers/cpufreq/intel_pstate.c

+170 −1
Original line number Diff line number Diff line
@@ -34,6 +34,10 @@ 
#include <asm/cpu_device_id.h>

#include <asm/cpufeature.h>



#if IS_ENABLED(CONFIG_ACPI)

#include <acpi/processor.h>

#endif



#define BYT_RATIOS		0x66a

#define BYT_VIDS		0x66b

#define BYT_TURBO_RATIOS	0x66c
@@ -113,6 +117,9 @@ struct cpudata { 
	u64	prev_mperf;

	u64	prev_tsc;

	struct sample sample;

#if IS_ENABLED(CONFIG_ACPI)

	struct acpi_processor_performance acpi_perf_data;

#endif

};



static struct cpudata **all_cpu_data;
@@ -143,6 +150,7 @@ struct cpu_defaults { 
static struct pstate_adjust_policy pid_params;

static struct pstate_funcs pstate_funcs;

static int hwp_active;

static int no_acpi_perf;



struct perf_limits {

	int no_turbo;
@@ -170,6 +178,153 @@ static struct perf_limits limits = { 
	.min_sysfs_pct = 0,

};



#if IS_ENABLED(CONFIG_ACPI)

/*

 * The max target pstate ratio is a 8 bit value in both PLATFORM_INFO MSR and

 * in TURBO_RATIO_LIMIT MSR, which pstate driver stores in max_pstate and

 * max_turbo_pstate fields. The PERF_CTL MSR contains 16 bit value for P state

 * ratio, out of it only high 8 bits are used. For example 0x1700 is setting

 * target ratio 0x17. The _PSS control value stores in a format which can be

 * directly written to PERF_CTL MSR. But in intel_pstate driver this shift

 * occurs during write to PERF_CTL (E.g. for cores core_set_pstate()).

 * This function converts the _PSS control value to intel pstate driver format

 * for comparison and assignment.

 */

static int convert_to_native_pstate_format(struct cpudata *cpu, int index)

{

	return cpu->acpi_perf_data.states[index].control >> 8;

}



static int intel_pstate_init_perf_limits(struct cpufreq_policy *policy)

{

	struct cpudata *cpu;

	int ret;

	bool turbo_absent = false;

	int max_pstate_index;

	int min_pss_ctl, max_pss_ctl, turbo_pss_ctl;

	int i;



	cpu = all_cpu_data[policy->cpu];



	pr_debug("intel_pstate: default limits 0x%x 0x%x 0x%x\n",

		 cpu->pstate.min_pstate, cpu->pstate.max_pstate,

		 cpu->pstate.turbo_pstate);



	if (!cpu->acpi_perf_data.shared_cpu_map &&

	    zalloc_cpumask_var_node(&cpu->acpi_perf_data.shared_cpu_map,

				    GFP_KERNEL, cpu_to_node(policy->cpu))) {

		return -ENOMEM;

	}



	ret = acpi_processor_register_performance(&cpu->acpi_perf_data,

						  policy->cpu);

	if (ret)

		return ret;



	/*

	 * Check if the control value in _PSS is for PERF_CTL MSR, which should

	 * guarantee that the states returned by it map to the states in our

	 * list directly.

	 */

	if (cpu->acpi_perf_data.control_register.space_id !=

						ACPI_ADR_SPACE_FIXED_HARDWARE)

		return -EIO;



	pr_debug("intel_pstate: CPU%u - ACPI _PSS perf data\n", policy->cpu);

	for (i = 0; i < cpu->acpi_perf_data.state_count; i++)

		pr_debug("     %cP%d: %u MHz, %u mW, 0x%x\n",

			 (i == cpu->acpi_perf_data.state ? '*' : ' '), i,

			 (u32) cpu->acpi_perf_data.states[i].core_frequency,

			 (u32) cpu->acpi_perf_data.states[i].power,

			 (u32) cpu->acpi_perf_data.states[i].control);



	/*

	 * If there is only one entry _PSS, simply ignore _PSS and continue as

	 * usual without taking _PSS into account

	 */

	if (cpu->acpi_perf_data.state_count < 2)

		return 0;



	turbo_pss_ctl = convert_to_native_pstate_format(cpu, 0);

	min_pss_ctl = convert_to_native_pstate_format(cpu,

					cpu->acpi_perf_data.state_count - 1);

	/* Check if there is a turbo freq in _PSS */

	if (turbo_pss_ctl <= cpu->pstate.max_pstate &&

	    turbo_pss_ctl > cpu->pstate.min_pstate) {

		pr_debug("intel_pstate: no turbo range exists in _PSS\n");

		limits.no_turbo = limits.turbo_disabled = 1;

		cpu->pstate.turbo_pstate = cpu->pstate.max_pstate;

		turbo_absent = true;

	}



	/* Check if the max non turbo p state < Intel P state max */

	max_pstate_index = turbo_absent ? 0 : 1;

	max_pss_ctl = convert_to_native_pstate_format(cpu, max_pstate_index);

	if (max_pss_ctl < cpu->pstate.max_pstate &&

	    max_pss_ctl > cpu->pstate.min_pstate)

		cpu->pstate.max_pstate = max_pss_ctl;



	/* check If min perf > Intel P State min */

	if (min_pss_ctl > cpu->pstate.min_pstate &&

	    min_pss_ctl < cpu->pstate.max_pstate) {

		cpu->pstate.min_pstate = min_pss_ctl;

		policy->cpuinfo.min_freq = min_pss_ctl * cpu->pstate.scaling;

	}



	if (turbo_absent)

		policy->cpuinfo.max_freq = cpu->pstate.max_pstate *

						cpu->pstate.scaling;

	else {

		policy->cpuinfo.max_freq = cpu->pstate.turbo_pstate *

						cpu->pstate.scaling;

		/*

		 * The _PSS table doesn't contain whole turbo frequency range.

		 * This just contains +1 MHZ above the max non turbo frequency,

		 * with control value corresponding to max turbo ratio. But

		 * when cpufreq set policy is called, it will call with this

		 * max frequency, which will cause a reduced performance as

		 * this driver uses real max turbo frequency as the max

		 * frequeny. So correct this frequency in _PSS table to

		 * correct max turbo frequency based on the turbo ratio.

		 * Also need to convert to MHz as _PSS freq is in MHz.

		 */

		cpu->acpi_perf_data.states[0].core_frequency =

						turbo_pss_ctl * 100;

	}



	pr_debug("intel_pstate: Updated limits using _PSS 0x%x 0x%x 0x%x\n",

		 cpu->pstate.min_pstate, cpu->pstate.max_pstate,

		 cpu->pstate.turbo_pstate);

	pr_debug("intel_pstate: policy max_freq=%d Khz min_freq = %d KHz\n",

		 policy->cpuinfo.max_freq, policy->cpuinfo.min_freq);



	return 0;

}



static int intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)

{

	struct cpudata *cpu;



	if (!no_acpi_perf)

		return 0;



	cpu = all_cpu_data[policy->cpu];

	acpi_processor_unregister_performance(policy->cpu);

	return 0;

}



#else

static int intel_pstate_init_perf_limits(struct cpufreq_policy *policy)

{

	return 0;

}



static int intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)

{

	return 0;

}

#endif



static inline void pid_reset(struct _pid *pid, int setpoint, int busy,

			     int deadband, int integral) {

	pid->setpoint = setpoint;
@@ -1115,18 +1270,30 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy) 
	policy->cpuinfo.min_freq = cpu->pstate.min_pstate * cpu->pstate.scaling;

	policy->cpuinfo.max_freq =

		cpu->pstate.turbo_pstate * cpu->pstate.scaling;

	if (!no_acpi_perf)

		intel_pstate_init_perf_limits(policy);

	/*

	 * If there is no acpi perf data or error, we ignore and use Intel P

	 * state calculated limits, So this is not fatal error.

	 */

	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;

	cpumask_set_cpu(policy->cpu, policy->cpus);



	return 0;

}



static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)

{

	return intel_pstate_exit_perf_limits(policy);

}



static struct cpufreq_driver intel_pstate_driver = {

	.flags		= CPUFREQ_CONST_LOOPS,

	.verify		= intel_pstate_verify_policy,

	.setpolicy	= intel_pstate_set_policy,

	.get		= intel_pstate_get,

	.init		= intel_pstate_cpu_init,

	.exit		= intel_pstate_cpu_exit,

	.stop_cpu	= intel_pstate_stop_cpu,

	.name		= "intel_pstate",

};
@@ -1168,7 +1335,6 @@ static void copy_cpu_funcs(struct pstate_funcs *funcs) 
}



#if IS_ENABLED(CONFIG_ACPI)

#include <acpi/processor.h>



static bool intel_pstate_no_acpi_pss(void)

{
@@ -1360,6 +1526,9 @@ static int __init intel_pstate_setup(char *str) 
		force_load = 1;

	if (!strcmp(str, "hwp_only"))

		hwp_only = 1;

	if (!strcmp(str, "no_acpi"))

		no_acpi_perf = 1;



	return 0;

}

early_param("intel_pstate", intel_pstate_setup);

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