tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * System Control and Power Interface (SCPI) based CPUFreq Interface driver
3 *
4 * It provides necessary ops to arm_big_little cpufreq driver.
5 *
6 * Copyright (C) 2015 ARM Ltd.
7 * Sudeep Holla <sudeep.holla@arm.com>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
14 * kind, whether express or implied; without even the implied warranty
15 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/cpu.h>
22#include <linux/cpufreq.h>
23#include <linux/module.h>
24#include <linux/platform_device.h>
25#include <linux/pm_opp.h>
26#include <linux/scpi_protocol.h>
27#include <linux/types.h>
28
29#include "arm_big_little.h"
30
31static struct scpi_ops *scpi_ops;
32
33static struct scpi_dvfs_info *scpi_get_dvfs_info(struct device *cpu_dev)
34{
35 int domain = topology_physical_package_id(cpu_dev->id);
36
37 if (domain < 0)
38 return ERR_PTR(-EINVAL);
39 return scpi_ops->dvfs_get_info(domain);
40}
41
42static int scpi_get_transition_latency(struct device *cpu_dev)
43{
44 struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev);
45
46 if (IS_ERR(info))
47 return PTR_ERR(info);
48 return info->latency;
49}
50
51static int scpi_init_opp_table(const struct cpumask *cpumask)
52{
53 int idx, ret;
54 struct scpi_opp *opp;
55 struct device *cpu_dev = get_cpu_device(cpumask_first(cpumask));
56 struct scpi_dvfs_info *info = scpi_get_dvfs_info(cpu_dev);
57
58 if (IS_ERR(info))
59 return PTR_ERR(info);
60
61 if (!info->opps)
62 return -EIO;
63
64 for (opp = info->opps, idx = 0; idx < info->count; idx++, opp++) {
65 ret = dev_pm_opp_add(cpu_dev, opp->freq, opp->m_volt * 1000);
66 if (ret) {
67 dev_warn(cpu_dev, "failed to add opp %uHz %umV\n",
68 opp->freq, opp->m_volt);
69 while (idx-- > 0)
70 dev_pm_opp_remove(cpu_dev, (--opp)->freq);
71 return ret;
72 }
73 }
74
75 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, cpumask);
76 if (ret)
77 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
78 __func__, ret);
79 return ret;
80}
81
82static struct cpufreq_arm_bL_ops scpi_cpufreq_ops = {
83 .name = "scpi",
84 .get_transition_latency = scpi_get_transition_latency,
85 .init_opp_table = scpi_init_opp_table,
86 .free_opp_table = dev_pm_opp_cpumask_remove_table,
87};
88
89static int scpi_cpufreq_probe(struct platform_device *pdev)
90{
91 scpi_ops = get_scpi_ops();
92 if (!scpi_ops)
93 return -EIO;
94
95 return bL_cpufreq_register(&scpi_cpufreq_ops);
96}
97
98static int scpi_cpufreq_remove(struct platform_device *pdev)
99{
100 bL_cpufreq_unregister(&scpi_cpufreq_ops);
101 scpi_ops = NULL;
102 return 0;
103}
104
105static struct platform_driver scpi_cpufreq_platdrv = {
106 .driver = {
107 .name = "scpi-cpufreq",
108 },
109 .probe = scpi_cpufreq_probe,
110 .remove = scpi_cpufreq_remove,
111};
112module_platform_driver(scpi_cpufreq_platdrv);
113
114MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
115MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
116MODULE_LICENSE("GPL v2");