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
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/*
* System Control and Power Interface (SCPI) based CPUFreq Interface driver
*
* Copyright (C) 2015 ARM Ltd.
* Sudeep Holla <sudeep.holla@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/pm_opp.h>
#include <linux/scpi_protocol.h>
#include <linux/slab.h>
#include <linux/types.h>
struct scpi_data {
struct clk *clk;
struct device *cpu_dev;
};
static struct scpi_ops *scpi_ops;
static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
{
struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
struct scpi_data *priv = policy->driver_data;
unsigned long rate = clk_get_rate(priv->clk);
return rate / 1000;
}
static int
scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
{
u64 rate = policy->freq_table[index].frequency * 1000;
struct scpi_data *priv = policy->driver_data;
int ret;
ret = clk_set_rate(priv->clk, rate);
if (ret)
return ret;
if (clk_get_rate(priv->clk) != rate)
return -EIO;
return 0;
}
static int
scpi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
{
int cpu, domain, tdomain;
struct device *tcpu_dev;
domain = scpi_ops->device_domain_id(cpu_dev);
if (domain < 0)
return domain;
for_each_possible_cpu(cpu) {
if (cpu == cpu_dev->id)
continue;
tcpu_dev = get_cpu_device(cpu);
if (!tcpu_dev)
continue;
tdomain = scpi_ops->device_domain_id(tcpu_dev);
if (tdomain == domain)
cpumask_set_cpu(cpu, cpumask);
}
return 0;
}
static int scpi_cpufreq_init(struct cpufreq_policy *policy)
{
int ret;
unsigned int latency;
struct device *cpu_dev;
struct scpi_data *priv;
struct cpufreq_frequency_table *freq_table;
cpu_dev = get_cpu_device(policy->cpu);
if (!cpu_dev) {
pr_err("failed to get cpu%d device\n", policy->cpu);
return -ENODEV;
}
ret = scpi_ops->add_opps_to_device(cpu_dev);
if (ret) {
dev_warn(cpu_dev, "failed to add opps to the device\n");
return ret;
}
ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
if (ret) {
dev_warn(cpu_dev, "failed to get sharing cpumask\n");
return ret;
}
ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
if (ret) {
dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
__func__, ret);
return ret;
}
ret = dev_pm_opp_get_opp_count(cpu_dev);
if (ret <= 0) {
dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
ret = -EPROBE_DEFER;
goto out_free_opp;
}
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv) {
ret = -ENOMEM;
goto out_free_opp;
}
ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
if (ret) {
dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
goto out_free_priv;
}
priv->cpu_dev = cpu_dev;
priv->clk = clk_get(cpu_dev, NULL);
if (IS_ERR(priv->clk)) {
dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
__func__, cpu_dev->id);
ret = PTR_ERR(priv->clk);
goto out_free_cpufreq_table;
}
policy->driver_data = priv;
policy->freq_table = freq_table;
/* scpi allows DVFS request for any domain from any CPU */
policy->dvfs_possible_from_any_cpu = true;
latency = scpi_ops->get_transition_latency(cpu_dev);
if (!latency)
latency = CPUFREQ_ETERNAL;
policy->cpuinfo.transition_latency = latency;
policy->fast_switch_possible = false;
return 0;
out_free_cpufreq_table:
dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
out_free_priv:
kfree(priv);
out_free_opp:
dev_pm_opp_remove_all_dynamic(cpu_dev);
return ret;
}
static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
{
struct scpi_data *priv = policy->driver_data;
clk_put(priv->clk);
dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
kfree(priv);
return 0;
}
static struct cpufreq_driver scpi_cpufreq_driver = {
.name = "scpi-cpufreq",
.flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
CPUFREQ_NEED_INITIAL_FREQ_CHECK |
CPUFREQ_IS_COOLING_DEV,
.verify = cpufreq_generic_frequency_table_verify,
.attr = cpufreq_generic_attr,
.get = scpi_cpufreq_get_rate,
.init = scpi_cpufreq_init,
.exit = scpi_cpufreq_exit,
.target_index = scpi_cpufreq_set_target,
.register_em = cpufreq_register_em_with_opp,
};
static int scpi_cpufreq_probe(struct platform_device *pdev)
{
int ret;
scpi_ops = get_scpi_ops();
if (!scpi_ops)
return -EIO;
ret = cpufreq_register_driver(&scpi_cpufreq_driver);
if (ret)
dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
__func__, ret);
return ret;
}
static int scpi_cpufreq_remove(struct platform_device *pdev)
{
cpufreq_unregister_driver(&scpi_cpufreq_driver);
scpi_ops = NULL;
return 0;
}
static struct platform_driver scpi_cpufreq_platdrv = {
.driver = {
.name = "scpi-cpufreq",
},
.probe = scpi_cpufreq_probe,
.remove = scpi_cpufreq_remove,
};
module_platform_driver(scpi_cpufreq_platdrv);
MODULE_ALIAS("platform:scpi-cpufreq");
MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
MODULE_LICENSE("GPL v2");
|
