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5a729246 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
8def3103 SH |
2 | /* |
3 | * System Control and Power Interface (SCPI) based CPUFreq Interface driver | |
4 | * | |
8def3103 SH |
5 | * Copyright (C) 2015 ARM Ltd. |
6 | * Sudeep Holla <sudeep.holla@arm.com> | |
8def3103 SH |
7 | */ |
8 | ||
9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
10 | ||
343a8d17 | 11 | #include <linux/clk.h> |
d9975b0b | 12 | #include <linux/cpu.h> |
8def3103 | 13 | #include <linux/cpufreq.h> |
343a8d17 | 14 | #include <linux/cpumask.h> |
343a8d17 | 15 | #include <linux/export.h> |
8def3103 | 16 | #include <linux/module.h> |
343a8d17 | 17 | #include <linux/of_platform.h> |
8def3103 SH |
18 | #include <linux/pm_opp.h> |
19 | #include <linux/scpi_protocol.h> | |
343a8d17 | 20 | #include <linux/slab.h> |
8def3103 SH |
21 | #include <linux/types.h> |
22 | ||
343a8d17 SH |
23 | struct scpi_data { |
24 | struct clk *clk; | |
25 | struct device *cpu_dev; | |
343a8d17 | 26 | }; |
8def3103 SH |
27 | |
28 | static struct scpi_ops *scpi_ops; | |
29 | ||
343a8d17 SH |
30 | static unsigned int scpi_cpufreq_get_rate(unsigned int cpu) |
31 | { | |
32 | struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); | |
33 | struct scpi_data *priv = policy->driver_data; | |
34 | unsigned long rate = clk_get_rate(priv->clk); | |
35 | ||
36 | return rate / 1000; | |
37 | } | |
38 | ||
39 | static int | |
40 | scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) | |
41 | { | |
1a0419b0 | 42 | u64 rate = policy->freq_table[index].frequency * 1000; |
343a8d17 | 43 | struct scpi_data *priv = policy->driver_data; |
343a8d17 SH |
44 | int ret; |
45 | ||
46 | ret = clk_set_rate(priv->clk, rate); | |
343a8d17 | 47 | |
9326fdf3 DE |
48 | if (ret) |
49 | return ret; | |
50 | ||
51 | if (clk_get_rate(priv->clk) != rate) | |
52 | return -EIO; | |
53 | ||
9326fdf3 | 54 | return 0; |
343a8d17 SH |
55 | } |
56 | ||
57 | static int | |
58 | scpi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) | |
8def3103 | 59 | { |
343a8d17 SH |
60 | int cpu, domain, tdomain; |
61 | struct device *tcpu_dev; | |
62 | ||
63 | domain = scpi_ops->device_domain_id(cpu_dev); | |
64 | if (domain < 0) | |
65 | return domain; | |
66 | ||
67 | for_each_possible_cpu(cpu) { | |
68 | if (cpu == cpu_dev->id) | |
69 | continue; | |
70 | ||
71 | tcpu_dev = get_cpu_device(cpu); | |
72 | if (!tcpu_dev) | |
73 | continue; | |
74 | ||
75 | tdomain = scpi_ops->device_domain_id(tcpu_dev); | |
76 | if (tdomain == domain) | |
77 | cpumask_set_cpu(cpu, cpumask); | |
78 | } | |
79 | ||
80 | return 0; | |
d9975b0b SH |
81 | } |
82 | ||
343a8d17 | 83 | static int scpi_cpufreq_init(struct cpufreq_policy *policy) |
d9975b0b | 84 | { |
c0f2e219 | 85 | int ret; |
343a8d17 SH |
86 | unsigned int latency; |
87 | struct device *cpu_dev; | |
88 | struct scpi_data *priv; | |
89 | struct cpufreq_frequency_table *freq_table; | |
90 | ||
91 | cpu_dev = get_cpu_device(policy->cpu); | |
92 | if (!cpu_dev) { | |
93 | pr_err("failed to get cpu%d device\n", policy->cpu); | |
94 | return -ENODEV; | |
95 | } | |
8def3103 | 96 | |
c0f2e219 SH |
97 | ret = scpi_ops->add_opps_to_device(cpu_dev); |
98 | if (ret) { | |
99 | dev_warn(cpu_dev, "failed to add opps to the device\n"); | |
100 | return ret; | |
8def3103 | 101 | } |
8def3103 | 102 | |
343a8d17 SH |
103 | ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus); |
104 | if (ret) { | |
105 | dev_warn(cpu_dev, "failed to get sharing cpumask\n"); | |
106 | return ret; | |
107 | } | |
108 | ||
109 | ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); | |
110 | if (ret) { | |
d9975b0b SH |
111 | dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", |
112 | __func__, ret); | |
343a8d17 SH |
113 | return ret; |
114 | } | |
115 | ||
116 | ret = dev_pm_opp_get_opp_count(cpu_dev); | |
117 | if (ret <= 0) { | |
118 | dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); | |
119 | ret = -EPROBE_DEFER; | |
120 | goto out_free_opp; | |
121 | } | |
122 | ||
123 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
124 | if (!priv) { | |
125 | ret = -ENOMEM; | |
126 | goto out_free_opp; | |
127 | } | |
128 | ||
129 | ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); | |
130 | if (ret) { | |
131 | dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); | |
132 | goto out_free_priv; | |
133 | } | |
134 | ||
135 | priv->cpu_dev = cpu_dev; | |
136 | priv->clk = clk_get(cpu_dev, NULL); | |
137 | if (IS_ERR(priv->clk)) { | |
138 | dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n", | |
139 | __func__, cpu_dev->id); | |
0725390d | 140 | ret = PTR_ERR(priv->clk); |
343a8d17 SH |
141 | goto out_free_cpufreq_table; |
142 | } | |
143 | ||
144 | policy->driver_data = priv; | |
472ada60 | 145 | policy->freq_table = freq_table; |
343a8d17 SH |
146 | |
147 | /* scpi allows DVFS request for any domain from any CPU */ | |
148 | policy->dvfs_possible_from_any_cpu = true; | |
149 | ||
150 | latency = scpi_ops->get_transition_latency(cpu_dev); | |
151 | if (!latency) | |
152 | latency = CPUFREQ_ETERNAL; | |
153 | ||
154 | policy->cpuinfo.transition_latency = latency; | |
155 | ||
156 | policy->fast_switch_possible = false; | |
6915d7ad | 157 | |
343a8d17 SH |
158 | return 0; |
159 | ||
343a8d17 SH |
160 | out_free_cpufreq_table: |
161 | dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); | |
162 | out_free_priv: | |
163 | kfree(priv); | |
164 | out_free_opp: | |
1690d8bb | 165 | dev_pm_opp_remove_all_dynamic(cpu_dev); |
343a8d17 | 166 | |
d9975b0b | 167 | return ret; |
8def3103 SH |
168 | } |
169 | ||
343a8d17 SH |
170 | static int scpi_cpufreq_exit(struct cpufreq_policy *policy) |
171 | { | |
172 | struct scpi_data *priv = policy->driver_data; | |
173 | ||
343a8d17 SH |
174 | clk_put(priv->clk); |
175 | dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); | |
1690d8bb | 176 | dev_pm_opp_remove_all_dynamic(priv->cpu_dev); |
31d4c528 | 177 | kfree(priv); |
343a8d17 SH |
178 | |
179 | return 0; | |
180 | } | |
181 | ||
343a8d17 SH |
182 | static struct cpufreq_driver scpi_cpufreq_driver = { |
183 | .name = "scpi-cpufreq", | |
5ae4a4b4 | 184 | .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY | |
cb772b8c AK |
185 | CPUFREQ_NEED_INITIAL_FREQ_CHECK | |
186 | CPUFREQ_IS_COOLING_DEV, | |
343a8d17 SH |
187 | .verify = cpufreq_generic_frequency_table_verify, |
188 | .attr = cpufreq_generic_attr, | |
189 | .get = scpi_cpufreq_get_rate, | |
190 | .init = scpi_cpufreq_init, | |
191 | .exit = scpi_cpufreq_exit, | |
343a8d17 | 192 | .target_index = scpi_cpufreq_set_target, |
4d584efa | 193 | .register_em = cpufreq_register_em_with_opp, |
8def3103 SH |
194 | }; |
195 | ||
196 | static int scpi_cpufreq_probe(struct platform_device *pdev) | |
197 | { | |
343a8d17 SH |
198 | int ret; |
199 | ||
8def3103 SH |
200 | scpi_ops = get_scpi_ops(); |
201 | if (!scpi_ops) | |
202 | return -EIO; | |
203 | ||
343a8d17 SH |
204 | ret = cpufreq_register_driver(&scpi_cpufreq_driver); |
205 | if (ret) | |
206 | dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n", | |
207 | __func__, ret); | |
208 | return ret; | |
8def3103 SH |
209 | } |
210 | ||
211 | static int scpi_cpufreq_remove(struct platform_device *pdev) | |
212 | { | |
343a8d17 | 213 | cpufreq_unregister_driver(&scpi_cpufreq_driver); |
8def3103 SH |
214 | scpi_ops = NULL; |
215 | return 0; | |
216 | } | |
217 | ||
218 | static struct platform_driver scpi_cpufreq_platdrv = { | |
219 | .driver = { | |
220 | .name = "scpi-cpufreq", | |
8def3103 SH |
221 | }, |
222 | .probe = scpi_cpufreq_probe, | |
223 | .remove = scpi_cpufreq_remove, | |
224 | }; | |
225 | module_platform_driver(scpi_cpufreq_platdrv); | |
226 | ||
c0382d04 | 227 | MODULE_ALIAS("platform:scpi-cpufreq"); |
8def3103 SH |
228 | MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); |
229 | MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver"); | |
230 | MODULE_LICENSE("GPL v2"); |