summaryrefslogtreecommitdiffstats
path: root/drivers/cpufreq/armada-8k-cpufreq.c
blob: 8a5ddb93fc58d24cf7cb88639c17e81e1bb382b7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
// SPDX-License-Identifier: GPL-2.0+
/*
 * CPUFreq support for Armada 8K
 *
 * Copyright (C) 2018 Marvell
 *
 * Omri Itach <omrii@marvell.com>
 * Gregory Clement <gregory.clement@bootlin.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/slab.h>

/*
 * Setup the opps list with the divider for the max frequency, that
 * will be filled at runtime.
 */
static const int opps_div[] __initconst = {1, 2, 3, 4};

static struct platform_device *armada_8k_pdev;

struct freq_table {
	struct device *cpu_dev;
	unsigned int freq[ARRAY_SIZE(opps_div)];
};

/* If the CPUs share the same clock, then they are in the same cluster. */
static void __init armada_8k_get_sharing_cpus(struct clk *cur_clk,
					      struct cpumask *cpumask)
{
	int cpu;

	for_each_possible_cpu(cpu) {
		struct device *cpu_dev;
		struct clk *clk;

		cpu_dev = get_cpu_device(cpu);
		if (!cpu_dev) {
			pr_warn("Failed to get cpu%d device\n", cpu);
			continue;
		}

		clk = clk_get(cpu_dev, 0);
		if (IS_ERR(clk)) {
			pr_warn("Cannot get clock for CPU %d\n", cpu);
		} else {
			if (clk_is_match(clk, cur_clk))
				cpumask_set_cpu(cpu, cpumask);

			clk_put(clk);
		}
	}
}

static int __init armada_8k_add_opp(struct clk *clk, struct device *cpu_dev,
				    struct freq_table *freq_tables,
				    int opps_index)
{
	unsigned int cur_frequency;
	unsigned int freq;
	int i, ret;

	/* Get nominal (current) CPU frequency. */
	cur_frequency = clk_get_rate(clk);
	if (!cur_frequency) {
		dev_err(cpu_dev, "Failed to get clock rate for this CPU\n");
		return -EINVAL;
	}

	freq_tables[opps_index].cpu_dev = cpu_dev;

	for (i = 0; i < ARRAY_SIZE(opps_div); i++) {
		freq = cur_frequency / opps_div[i];

		ret = dev_pm_opp_add(cpu_dev, freq, 0);
		if (ret)
			return ret;

		freq_tables[opps_index].freq[i] = freq;
	}

	return 0;
}

static void armada_8k_cpufreq_free_table(struct freq_table *freq_tables)
{
	int opps_index, nb_cpus = num_possible_cpus();

	for (opps_index = 0 ; opps_index <= nb_cpus; opps_index++) {
		int i;

		/* If cpu_dev is NULL then we reached the end of the array */
		if (!freq_tables[opps_index].cpu_dev)
			break;

		for (i = 0; i < ARRAY_SIZE(opps_div); i++) {
			/*
			 * A 0Hz frequency is not valid, this meant
			 * that it was not yet initialized so there is
			 * no more opp to free
			 */
			if (freq_tables[opps_index].freq[i] == 0)
				break;

			dev_pm_opp_remove(freq_tables[opps_index].cpu_dev,
					  freq_tables[opps_index].freq[i]);
		}
	}

	kfree(freq_tables);
}

static int __init armada_8k_cpufreq_init(void)
{
	int ret = 0, opps_index = 0, cpu, nb_cpus;
	struct freq_table *freq_tables;
	struct device_node *node;
	struct cpumask cpus;

	node = of_find_compatible_node(NULL, NULL, "marvell,ap806-cpu-clock");
	if (!node || !of_device_is_available(node))
		return -ENODEV;

	nb_cpus = num_possible_cpus();
	freq_tables = kcalloc(nb_cpus, sizeof(*freq_tables), GFP_KERNEL);
	cpumask_copy(&cpus, cpu_possible_mask);

	/*
	 * For each CPU, this loop registers the operating points
	 * supported (which are the nominal CPU frequency and full integer
	 * divisions of it).
	 */
	for_each_cpu(cpu, &cpus) {
		struct cpumask shared_cpus;
		struct device *cpu_dev;
		struct clk *clk;

		cpu_dev = get_cpu_device(cpu);

		if (!cpu_dev) {
			pr_err("Cannot get CPU %d\n", cpu);
			continue;
		}

		clk = clk_get(cpu_dev, 0);

		if (IS_ERR(clk)) {
			pr_err("Cannot get clock for CPU %d\n", cpu);
			ret = PTR_ERR(clk);
			goto remove_opp;
		}

		ret = armada_8k_add_opp(clk, cpu_dev, freq_tables, opps_index);
		if (ret) {
			clk_put(clk);
			goto remove_opp;
		}

		opps_index++;
		cpumask_clear(&shared_cpus);
		armada_8k_get_sharing_cpus(clk, &shared_cpus);
		dev_pm_opp_set_sharing_cpus(cpu_dev, &shared_cpus);
		cpumask_andnot(&cpus, &cpus, &shared_cpus);
		clk_put(clk);
	}

	armada_8k_pdev = platform_device_register_simple("cpufreq-dt", -1,
							 NULL, 0);
	ret = PTR_ERR_OR_ZERO(armada_8k_pdev);
	if (ret)
		goto remove_opp;

	platform_set_drvdata(armada_8k_pdev, freq_tables);

	return 0;

remove_opp:
	armada_8k_cpufreq_free_table(freq_tables);
	return ret;
}
module_init(armada_8k_cpufreq_init);

static void __exit armada_8k_cpufreq_exit(void)
{
	struct freq_table *freq_tables = platform_get_drvdata(armada_8k_pdev);

	platform_device_unregister(armada_8k_pdev);
	armada_8k_cpufreq_free_table(freq_tables);
}
module_exit(armada_8k_cpufreq_exit);

MODULE_AUTHOR("Gregory Clement <gregory.clement@bootlin.com>");
MODULE_DESCRIPTION("Armada 8K cpufreq driver");
MODULE_LICENSE("GPL");