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8def3103 SH |
1 | /* |
2 | * System Control and Power Interface (SCPI) based CPUFreq Interface driver | |
3 | * | |
8def3103 SH |
4 | * Copyright (C) 2015 ARM Ltd. |
5 | * Sudeep Holla <sudeep.holla@arm.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed "as is" WITHOUT ANY WARRANTY of any | |
12 | * kind, whether express or implied; without even the implied warranty | |
13 | * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | */ | |
16 | ||
17 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
18 | ||
343a8d17 | 19 | #include <linux/clk.h> |
d9975b0b | 20 | #include <linux/cpu.h> |
8def3103 | 21 | #include <linux/cpufreq.h> |
343a8d17 | 22 | #include <linux/cpumask.h> |
343a8d17 | 23 | #include <linux/export.h> |
8def3103 | 24 | #include <linux/module.h> |
343a8d17 | 25 | #include <linux/of_platform.h> |
8def3103 SH |
26 | #include <linux/pm_opp.h> |
27 | #include <linux/scpi_protocol.h> | |
343a8d17 | 28 | #include <linux/slab.h> |
8def3103 SH |
29 | #include <linux/types.h> |
30 | ||
343a8d17 SH |
31 | struct scpi_data { |
32 | struct clk *clk; | |
33 | struct device *cpu_dev; | |
343a8d17 | 34 | }; |
8def3103 SH |
35 | |
36 | static struct scpi_ops *scpi_ops; | |
37 | ||
343a8d17 SH |
38 | static unsigned int scpi_cpufreq_get_rate(unsigned int cpu) |
39 | { | |
40 | struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); | |
41 | struct scpi_data *priv = policy->driver_data; | |
42 | unsigned long rate = clk_get_rate(priv->clk); | |
43 | ||
44 | return rate / 1000; | |
45 | } | |
46 | ||
47 | static int | |
48 | scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) | |
49 | { | |
1a0419b0 | 50 | u64 rate = policy->freq_table[index].frequency * 1000; |
343a8d17 | 51 | struct scpi_data *priv = policy->driver_data; |
343a8d17 SH |
52 | int ret; |
53 | ||
54 | ret = clk_set_rate(priv->clk, rate); | |
343a8d17 | 55 | |
9326fdf3 DE |
56 | if (ret) |
57 | return ret; | |
58 | ||
59 | if (clk_get_rate(priv->clk) != rate) | |
60 | return -EIO; | |
61 | ||
9326fdf3 | 62 | return 0; |
343a8d17 SH |
63 | } |
64 | ||
65 | static int | |
66 | scpi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) | |
8def3103 | 67 | { |
343a8d17 SH |
68 | int cpu, domain, tdomain; |
69 | struct device *tcpu_dev; | |
70 | ||
71 | domain = scpi_ops->device_domain_id(cpu_dev); | |
72 | if (domain < 0) | |
73 | return domain; | |
74 | ||
75 | for_each_possible_cpu(cpu) { | |
76 | if (cpu == cpu_dev->id) | |
77 | continue; | |
78 | ||
79 | tcpu_dev = get_cpu_device(cpu); | |
80 | if (!tcpu_dev) | |
81 | continue; | |
82 | ||
83 | tdomain = scpi_ops->device_domain_id(tcpu_dev); | |
84 | if (tdomain == domain) | |
85 | cpumask_set_cpu(cpu, cpumask); | |
86 | } | |
87 | ||
88 | return 0; | |
d9975b0b SH |
89 | } |
90 | ||
343a8d17 | 91 | static int scpi_cpufreq_init(struct cpufreq_policy *policy) |
d9975b0b | 92 | { |
c0f2e219 | 93 | int ret; |
343a8d17 SH |
94 | unsigned int latency; |
95 | struct device *cpu_dev; | |
96 | struct scpi_data *priv; | |
97 | struct cpufreq_frequency_table *freq_table; | |
98 | ||
99 | cpu_dev = get_cpu_device(policy->cpu); | |
100 | if (!cpu_dev) { | |
101 | pr_err("failed to get cpu%d device\n", policy->cpu); | |
102 | return -ENODEV; | |
103 | } | |
8def3103 | 104 | |
c0f2e219 SH |
105 | ret = scpi_ops->add_opps_to_device(cpu_dev); |
106 | if (ret) { | |
107 | dev_warn(cpu_dev, "failed to add opps to the device\n"); | |
108 | return ret; | |
8def3103 | 109 | } |
8def3103 | 110 | |
343a8d17 SH |
111 | ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus); |
112 | if (ret) { | |
113 | dev_warn(cpu_dev, "failed to get sharing cpumask\n"); | |
114 | return ret; | |
115 | } | |
116 | ||
117 | ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); | |
118 | if (ret) { | |
d9975b0b SH |
119 | dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", |
120 | __func__, ret); | |
343a8d17 SH |
121 | return ret; |
122 | } | |
123 | ||
124 | ret = dev_pm_opp_get_opp_count(cpu_dev); | |
125 | if (ret <= 0) { | |
126 | dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); | |
127 | ret = -EPROBE_DEFER; | |
128 | goto out_free_opp; | |
129 | } | |
130 | ||
131 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
132 | if (!priv) { | |
133 | ret = -ENOMEM; | |
134 | goto out_free_opp; | |
135 | } | |
136 | ||
137 | ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); | |
138 | if (ret) { | |
139 | dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); | |
140 | goto out_free_priv; | |
141 | } | |
142 | ||
143 | priv->cpu_dev = cpu_dev; | |
144 | priv->clk = clk_get(cpu_dev, NULL); | |
145 | if (IS_ERR(priv->clk)) { | |
146 | dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n", | |
147 | __func__, cpu_dev->id); | |
0725390d | 148 | ret = PTR_ERR(priv->clk); |
343a8d17 SH |
149 | goto out_free_cpufreq_table; |
150 | } | |
151 | ||
152 | policy->driver_data = priv; | |
472ada60 | 153 | policy->freq_table = freq_table; |
343a8d17 SH |
154 | |
155 | /* scpi allows DVFS request for any domain from any CPU */ | |
156 | policy->dvfs_possible_from_any_cpu = true; | |
157 | ||
158 | latency = scpi_ops->get_transition_latency(cpu_dev); | |
159 | if (!latency) | |
160 | latency = CPUFREQ_ETERNAL; | |
161 | ||
162 | policy->cpuinfo.transition_latency = latency; | |
163 | ||
164 | policy->fast_switch_possible = false; | |
6915d7ad | 165 | |
0e0ffa85 | 166 | dev_pm_opp_of_register_em(cpu_dev, policy->cpus); |
6915d7ad | 167 | |
343a8d17 SH |
168 | return 0; |
169 | ||
343a8d17 SH |
170 | out_free_cpufreq_table: |
171 | dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); | |
172 | out_free_priv: | |
173 | kfree(priv); | |
174 | out_free_opp: | |
1690d8bb | 175 | dev_pm_opp_remove_all_dynamic(cpu_dev); |
343a8d17 | 176 | |
d9975b0b | 177 | return ret; |
8def3103 SH |
178 | } |
179 | ||
343a8d17 SH |
180 | static int scpi_cpufreq_exit(struct cpufreq_policy *policy) |
181 | { | |
182 | struct scpi_data *priv = policy->driver_data; | |
183 | ||
343a8d17 SH |
184 | clk_put(priv->clk); |
185 | dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); | |
1690d8bb | 186 | dev_pm_opp_remove_all_dynamic(priv->cpu_dev); |
31d4c528 | 187 | kfree(priv); |
343a8d17 SH |
188 | |
189 | return 0; | |
190 | } | |
191 | ||
343a8d17 SH |
192 | static struct cpufreq_driver scpi_cpufreq_driver = { |
193 | .name = "scpi-cpufreq", | |
5ae4a4b4 | 194 | .flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY | |
cb772b8c AK |
195 | CPUFREQ_NEED_INITIAL_FREQ_CHECK | |
196 | CPUFREQ_IS_COOLING_DEV, | |
343a8d17 SH |
197 | .verify = cpufreq_generic_frequency_table_verify, |
198 | .attr = cpufreq_generic_attr, | |
199 | .get = scpi_cpufreq_get_rate, | |
200 | .init = scpi_cpufreq_init, | |
201 | .exit = scpi_cpufreq_exit, | |
343a8d17 | 202 | .target_index = scpi_cpufreq_set_target, |
8def3103 SH |
203 | }; |
204 | ||
205 | static int scpi_cpufreq_probe(struct platform_device *pdev) | |
206 | { | |
343a8d17 SH |
207 | int ret; |
208 | ||
8def3103 SH |
209 | scpi_ops = get_scpi_ops(); |
210 | if (!scpi_ops) | |
211 | return -EIO; | |
212 | ||
343a8d17 SH |
213 | ret = cpufreq_register_driver(&scpi_cpufreq_driver); |
214 | if (ret) | |
215 | dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n", | |
216 | __func__, ret); | |
217 | return ret; | |
8def3103 SH |
218 | } |
219 | ||
220 | static int scpi_cpufreq_remove(struct platform_device *pdev) | |
221 | { | |
343a8d17 | 222 | cpufreq_unregister_driver(&scpi_cpufreq_driver); |
8def3103 SH |
223 | scpi_ops = NULL; |
224 | return 0; | |
225 | } | |
226 | ||
227 | static struct platform_driver scpi_cpufreq_platdrv = { | |
228 | .driver = { | |
229 | .name = "scpi-cpufreq", | |
8def3103 SH |
230 | }, |
231 | .probe = scpi_cpufreq_probe, | |
232 | .remove = scpi_cpufreq_remove, | |
233 | }; | |
234 | module_platform_driver(scpi_cpufreq_platdrv); | |
235 | ||
c0382d04 | 236 | MODULE_ALIAS("platform:scpi-cpufreq"); |
8def3103 SH |
237 | MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); |
238 | MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver"); | |
239 | MODULE_LICENSE("GPL v2"); |