1/*
  2 * CPPC (Collaborative Processor Performance Control) driver for
  3 * interfacing with the CPUfreq layer and governors. See
  4 * cppc_acpi.c for CPPC specific methods.
  5 *
  6 * (C) Copyright 2014, 2015 Linaro Ltd.
  7 * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
  8 *
  9 * This program is free software; you can redistribute it and/or
 10 * modify it under the terms of the GNU General Public License
 11 * as published by the Free Software Foundation; version 2
 12 * of the License.
 13 */
 14
 15#define pr_fmt(fmt)	"CPPC Cpufreq:"	fmt
 16
 17#include <linux/kernel.h>
 18#include <linux/module.h>
 19#include <linux/delay.h>
 20#include <linux/cpu.h>
 21#include <linux/cpufreq.h>
 22#include <linux/vmalloc.h>
 23
 24#include <acpi/cppc_acpi.h>
 25
 26/*
 27 * These structs contain information parsed from per CPU
 28 * ACPI _CPC structures.
 29 * e.g. For each CPU the highest, lowest supported
 30 * performance capabilities, desired performance level
 31 * requested etc.
 32 */
 33static struct cpudata **all_cpu_data;
 34
 35static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
 36		unsigned int target_freq,
 37		unsigned int relation)
 38{
 39	struct cpudata *cpu;
 40	struct cpufreq_freqs freqs;
 41	int ret = 0;
 42
 43	cpu = all_cpu_data[policy->cpu];
 44
 45	cpu->perf_ctrls.desired_perf = target_freq;
 46	freqs.old = policy->cur;
 47	freqs.new = target_freq;
 48
 49	cpufreq_freq_transition_begin(policy, &freqs);
 50	ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
 51	cpufreq_freq_transition_end(policy, &freqs, ret != 0);
 52
 53	if (ret)
 54		pr_debug("Failed to set target on CPU:%d. ret:%d\n",
 55				cpu->cpu, ret);
 56
 57	return ret;
 58}
 59
 60static int cppc_verify_policy(struct cpufreq_policy *policy)
 61{
 62	cpufreq_verify_within_cpu_limits(policy);
 63	return 0;
 64}
 65
 66static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
 67{
 68	int cpu_num = policy->cpu;
 69	struct cpudata *cpu = all_cpu_data[cpu_num];
 70	int ret;
 71
 72	cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
 73
 74	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
 75	if (ret)
 76		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
 77				cpu->perf_caps.lowest_perf, cpu_num, ret);
 78}
 79
 80static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 81{
 82	struct cpudata *cpu;
 83	unsigned int cpu_num = policy->cpu;
 84	int ret = 0;
 85
 86	cpu = all_cpu_data[policy->cpu];
 87
 88	cpu->cpu = cpu_num;
 89	ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
 90
 91	if (ret) {
 92		pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
 93				cpu_num, ret);
 94		return ret;
 95	}
 96
 97	policy->min = cpu->perf_caps.lowest_perf;
 98	policy->max = cpu->perf_caps.highest_perf;
 99	policy->cpuinfo.min_freq = policy->min;
100	policy->cpuinfo.max_freq = policy->max;
101	policy->shared_type = cpu->shared_type;
102
103	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
104		cpumask_copy(policy->cpus, cpu->shared_cpu_map);
105	else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
106		/* Support only SW_ANY for now. */
107		pr_debug("Unsupported CPU co-ord type\n");
108		return -EFAULT;
109	}
110
111	cpumask_set_cpu(policy->cpu, policy->cpus);
112	cpu->cur_policy = policy;
113
114	/* Set policy->cur to max now. The governors will adjust later. */
115	policy->cur = cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
116
117	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
118	if (ret)
119		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
120				cpu->perf_caps.highest_perf, cpu_num, ret);
121
122	return ret;
123}
124
125static struct cpufreq_driver cppc_cpufreq_driver = {
126	.flags = CPUFREQ_CONST_LOOPS,
127	.verify = cppc_verify_policy,
128	.target = cppc_cpufreq_set_target,
129	.init = cppc_cpufreq_cpu_init,
130	.stop_cpu = cppc_cpufreq_stop_cpu,
131	.name = "cppc_cpufreq",
132};
133
134static int __init cppc_cpufreq_init(void)
135{
136	int i, ret = 0;
137	struct cpudata *cpu;
138
139	if (acpi_disabled)
140		return -ENODEV;
141
142	all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
143	if (!all_cpu_data)
144		return -ENOMEM;
145
146	for_each_possible_cpu(i) {
147		all_cpu_data[i] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
148		if (!all_cpu_data[i])
149			goto out;
150
151		cpu = all_cpu_data[i];
152		if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
153			goto out;
154	}
155
156	ret = acpi_get_psd_map(all_cpu_data);
157	if (ret) {
158		pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
159		goto out;
160	}
161
162	ret = cpufreq_register_driver(&cppc_cpufreq_driver);
163	if (ret)
164		goto out;
165
166	return ret;
167
168out:
169	for_each_possible_cpu(i)
170		kfree(all_cpu_data[i]);
171
172	kfree(all_cpu_data);
173	return -ENODEV;
174}
175
176late_initcall(cppc_cpufreq_init);