/* * 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);