drivers/cpufreq/cppc_cpufreq.c - arm/linux - Git at Google

 /*
  * CPPC (Collaborative Processor Performance Control) driver for
  * interfacing with the CPUfreq layer and governors. See
  * cppc_acpi.c for CPPC specific methods.
  *
  * (C) Copyright 2014, 2015 Linaro Ltd.
  * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
  *
  * 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; version 2
  * of the License.
  */

 #define pr_fmt(fmt)	"CPPC Cpufreq:"	fmt

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/dmi.h>
 #include <linux/vmalloc.h>

 #include <asm/unaligned.h>

 #include <acpi/cppc_acpi.h>

 /* Minimum struct length needed for the DMI processor entry we want */
 #define DMI_ENTRY_PROCESSOR_MIN_LENGTH	48

 /* Offest in the DMI processor structure for the max frequency */
 #define DMI_PROCESSOR_MAX_SPEED  0x14

 /*
  * These structs contain information parsed from per CPU
  * ACPI _CPC structures.
  * e.g. For each CPU the highest, lowest supported
  * performance capabilities, desired performance level
  * requested etc.
  */
 static struct cppc_cpudata **all_cpu_data;

 /* Capture the max KHz from DMI */
 static u64 cppc_dmi_max_khz;

 /* Callback function used to retrieve the max frequency from DMI */
 static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
 {
 	const u8 *dmi_data = (const u8 *)dm;
 	u16 *mhz = (u16 *)private;

 	if (dm->type == DMI_ENTRY_PROCESSOR &&
 	    dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
 		u16 val = (u16)get_unaligned((const u16 *)
 				(dmi_data + DMI_PROCESSOR_MAX_SPEED));
 		*mhz = val > *mhz ? val : *mhz;
 	}
 }

 /* Look up the max frequency in DMI */
 static u64 cppc_get_dmi_max_khz(void)
 {
 	u16 mhz = 0;

 	dmi_walk(cppc_find_dmi_mhz, &mhz);

 	/*
 	 * Real stupid fallback value, just in case there is no
 	 * actual value set.
 	 */
 	mhz = mhz ? mhz : 1;

 	return (1000 * mhz);
 }

 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
 		unsigned int target_freq,
 		unsigned int relation)
 {
 	struct cppc_cpudata *cpu;
 	struct cpufreq_freqs freqs;
 	u32 desired_perf;
 	int ret = 0;

 	cpu = all_cpu_data[policy->cpu];

 	desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
 	/* Return if it is exactly the same perf */
 	if (desired_perf == cpu->perf_ctrls.desired_perf)
 		return ret;

 	cpu->perf_ctrls.desired_perf = desired_perf;
 	freqs.old = policy->cur;
 	freqs.new = target_freq;

 	cpufreq_freq_transition_begin(policy, &freqs);
 	ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
 	cpufreq_freq_transition_end(policy, &freqs, ret != 0);

 	if (ret)
 		pr_debug("Failed to set target on CPU:%d. ret:%d\n",
 				cpu->cpu, ret);

 	return ret;
 }

 static int cppc_verify_policy(struct cpufreq_policy *policy)
 {
 	cpufreq_verify_within_cpu_limits(policy);
 	return 0;
 }

 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
 {
 	int cpu_num = policy->cpu;
 	struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
 	int ret;

 	cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;

 	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
 	if (ret)
 		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
 				cpu->perf_caps.lowest_perf, cpu_num, ret);
 }

 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 {
 	struct cppc_cpudata *cpu;
 	unsigned int cpu_num = policy->cpu;
 	int ret = 0;

 	cpu = all_cpu_data[policy->cpu];

 	cpu->cpu = cpu_num;
 	ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);

 	if (ret) {
 		pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
 				cpu_num, ret);
 		return ret;
 	}

 	cppc_dmi_max_khz = cppc_get_dmi_max_khz();

 	/*
 	 * Set min to lowest nonlinear perf to avoid any efficiency penalty (see
 	 * Section 8.4.7.1.1.5 of ACPI 6.1 spec)
 	 */
 	policy->min = cpu->perf_caps.lowest_nonlinear_perf * cppc_dmi_max_khz /
 		cpu->perf_caps.highest_perf;
 	policy->max = cppc_dmi_max_khz;

 	/*
 	 * Set cpuinfo.min_freq to Lowest to make the full range of performance
 	 * available if userspace wants to use any perf between lowest & lowest
 	 * nonlinear perf
 	 */
 	policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz /
 		cpu->perf_caps.highest_perf;
 	policy->cpuinfo.max_freq = cppc_dmi_max_khz;

 	policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
 	policy->shared_type = cpu->shared_type;

 	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 		cpumask_copy(policy->cpus, cpu->shared_cpu_map);
 	else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
 		/* Support only SW_ANY for now. */
 		pr_debug("Unsupported CPU co-ord type\n");
 		return -EFAULT;
 	}

 	cpu->cur_policy = policy;

 	/* Set policy->cur to max now. The governors will adjust later. */
 	policy->cur = cppc_dmi_max_khz;
 	cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;

 	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
 	if (ret)
 		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
 				cpu->perf_caps.highest_perf, cpu_num, ret);

 	return ret;
 }

 static struct cpufreq_driver cppc_cpufreq_driver = {
 	.flags = CPUFREQ_CONST_LOOPS,
 	.verify = cppc_verify_policy,
 	.target = cppc_cpufreq_set_target,
 	.init = cppc_cpufreq_cpu_init,
 	.stop_cpu = cppc_cpufreq_stop_cpu,
 	.name = "cppc_cpufreq",
 };

 static int __init cppc_cpufreq_init(void)
 {
 	int i, ret = 0;
 	struct cppc_cpudata *cpu;

 	if (acpi_disabled)
 		return -ENODEV;

 	all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
 	if (!all_cpu_data)
 		return -ENOMEM;

 	for_each_possible_cpu(i) {
 		all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
 		if (!all_cpu_data[i])
 			goto out;

 		cpu = all_cpu_data[i];
 		if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
 			goto out;
 	}

 	ret = acpi_get_psd_map(all_cpu_data);
 	if (ret) {
 		pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
 		goto out;
 	}

 	ret = cpufreq_register_driver(&cppc_cpufreq_driver);
 	if (ret)
 		goto out;

 	return ret;

 out:
 	for_each_possible_cpu(i)
 		kfree(all_cpu_data[i]);

 	kfree(all_cpu_data);
 	return -ENODEV;
 }

 static void __exit cppc_cpufreq_exit(void)
 {
 	struct cppc_cpudata *cpu;
 	int i;

 	cpufreq_unregister_driver(&cppc_cpufreq_driver);

 	for_each_possible_cpu(i) {
 		cpu = all_cpu_data[i];
 		free_cpumask_var(cpu->shared_cpu_map);
 		kfree(cpu);
 	}

 	kfree(all_cpu_data);
 }

 module_exit(cppc_cpufreq_exit);
 MODULE_AUTHOR("Ashwin Chaugule");
 MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
 MODULE_LICENSE("GPL");

 late_initcall(cppc_cpufreq_init);

 static const struct acpi_device_id cppc_acpi_ids[] = {
 	{ACPI_PROCESSOR_DEVICE_HID, },
 	{}
 };

 MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);
	/*
	* CPPC (Collaborative Processor Performance Control) driver for
	* interfacing with the CPUfreq layer and governors. See
	* cppc_acpi.c for CPPC specific methods.
	*
	* (C) Copyright 2014, 2015 Linaro Ltd.
	* Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
	*
	* 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; version 2
	* of the License.
	*/

	#define pr_fmt(fmt) "CPPC Cpufreq:" fmt

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/delay.h>
	#include <linux/cpu.h>
	#include <linux/cpufreq.h>
	#include <linux/dmi.h>
	#include <linux/vmalloc.h>

	#include <asm/unaligned.h>

	#include <acpi/cppc_acpi.h>

	/* Minimum struct length needed for the DMI processor entry we want */
	#define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48

	/* Offest in the DMI processor structure for the max frequency */
	#define DMI_PROCESSOR_MAX_SPEED 0x14

	/*
	* These structs contain information parsed from per CPU
	* ACPI _CPC structures.
	* e.g. For each CPU the highest, lowest supported
	* performance capabilities, desired performance level
	* requested etc.
	*/
	static struct cppc_cpudata **all_cpu_data;

	/* Capture the max KHz from DMI */
	static u64 cppc_dmi_max_khz;

	/* Callback function used to retrieve the max frequency from DMI */
	static void cppc_find_dmi_mhz(const struct dmi_header dm, void private)
	{
	const u8 dmi_data = (const u8 )dm;
	u16 mhz = (u16 )private;

	if (dm->type == DMI_ENTRY_PROCESSOR &&
	dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
	u16 val = (u16)get_unaligned((const u16 *)
	(dmi_data + DMI_PROCESSOR_MAX_SPEED));
	mhz = val > mhz ? val : *mhz;
	}
	}

	/* Look up the max frequency in DMI */
	static u64 cppc_get_dmi_max_khz(void)
	{
	u16 mhz = 0;

	dmi_walk(cppc_find_dmi_mhz, &mhz);

	/*
	* Real stupid fallback value, just in case there is no
	* actual value set.
	*/
	mhz = mhz ? mhz : 1;

	return (1000 * mhz);
	}

	static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
	unsigned int target_freq,
	unsigned int relation)
	{
	struct cppc_cpudata *cpu;
	struct cpufreq_freqs freqs;
	u32 desired_perf;
	int ret = 0;

	cpu = all_cpu_data[policy->cpu];

	desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
	/* Return if it is exactly the same perf */
	if (desired_perf == cpu->perf_ctrls.desired_perf)
	return ret;

	cpu->perf_ctrls.desired_perf = desired_perf;
	freqs.old = policy->cur;
	freqs.new = target_freq;

	cpufreq_freq_transition_begin(policy, &freqs);
	ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
	cpufreq_freq_transition_end(policy, &freqs, ret != 0);

	if (ret)
	pr_debug("Failed to set target on CPU:%d. ret:%d\n",
	cpu->cpu, ret);

	return ret;
	}

	static int cppc_verify_policy(struct cpufreq_policy *policy)
	{
	cpufreq_verify_within_cpu_limits(policy);
	return 0;
	}

	static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
	{
	int cpu_num = policy->cpu;
	struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
	int ret;

	cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;

	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
	if (ret)
	pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
	cpu->perf_caps.lowest_perf, cpu_num, ret);
	}

	static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
	{
	struct cppc_cpudata *cpu;
	unsigned int cpu_num = policy->cpu;
	int ret = 0;

	cpu = all_cpu_data[policy->cpu];

	cpu->cpu = cpu_num;
	ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);

	if (ret) {
	pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
	cpu_num, ret);
	return ret;
	}

	cppc_dmi_max_khz = cppc_get_dmi_max_khz();

	/*
	* Set min to lowest nonlinear perf to avoid any efficiency penalty (see
	* Section 8.4.7.1.1.5 of ACPI 6.1 spec)
	*/
	policy->min = cpu->perf_caps.lowest_nonlinear_perf * cppc_dmi_max_khz /
	cpu->perf_caps.highest_perf;
	policy->max = cppc_dmi_max_khz;

	/*
	* Set cpuinfo.min_freq to Lowest to make the full range of performance
	* available if userspace wants to use any perf between lowest & lowest
	* nonlinear perf
	*/
	policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz /
	cpu->perf_caps.highest_perf;
	policy->cpuinfo.max_freq = cppc_dmi_max_khz;

	policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
	policy->shared_type = cpu->shared_type;

	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
	cpumask_copy(policy->cpus, cpu->shared_cpu_map);
	else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
	/* Support only SW_ANY for now. */
	pr_debug("Unsupported CPU co-ord type\n");
	return -EFAULT;
	}

	cpu->cur_policy = policy;

	/* Set policy->cur to max now. The governors will adjust later. */
	policy->cur = cppc_dmi_max_khz;
	cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;

	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
	if (ret)
	pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
	cpu->perf_caps.highest_perf, cpu_num, ret);

	return ret;
	}

	static struct cpufreq_driver cppc_cpufreq_driver = {
	.flags = CPUFREQ_CONST_LOOPS,
	.verify = cppc_verify_policy,
	.target = cppc_cpufreq_set_target,
	.init = cppc_cpufreq_cpu_init,
	.stop_cpu = cppc_cpufreq_stop_cpu,
	.name = "cppc_cpufreq",
	};

	static int __init cppc_cpufreq_init(void)
	{
	int i, ret = 0;
	struct cppc_cpudata *cpu;

	if (acpi_disabled)
	return -ENODEV;

	all_cpu_data = kzalloc(sizeof(void ) num_possible_cpus(), GFP_KERNEL);
	if (!all_cpu_data)
	return -ENOMEM;

	for_each_possible_cpu(i) {
	all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
	if (!all_cpu_data[i])
	goto out;

	cpu = all_cpu_data[i];
	if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
	goto out;
	}

	ret = acpi_get_psd_map(all_cpu_data);
	if (ret) {
	pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
	goto out;
	}

	ret = cpufreq_register_driver(&cppc_cpufreq_driver);
	if (ret)
	goto out;

	return ret;

	out:
	for_each_possible_cpu(i)
	kfree(all_cpu_data[i]);

	kfree(all_cpu_data);
	return -ENODEV;
	}

	static void __exit cppc_cpufreq_exit(void)
	{
	struct cppc_cpudata *cpu;
	int i;

	cpufreq_unregister_driver(&cppc_cpufreq_driver);

	for_each_possible_cpu(i) {
	cpu = all_cpu_data[i];
	free_cpumask_var(cpu->shared_cpu_map);
	kfree(cpu);
	}

	kfree(all_cpu_data);
	}

	module_exit(cppc_cpufreq_exit);
	MODULE_AUTHOR("Ashwin Chaugule");
	MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
	MODULE_LICENSE("GPL");

	late_initcall(cppc_cpufreq_init);

	static const struct acpi_device_id cppc_acpi_ids[] = {
	{ACPI_PROCESSOR_DEVICE_HID, },
	{}
	};

	MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);