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8def3103 SH |
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 | ||
343a8d17 | 21 | #include <linux/clk.h> |
d9975b0b | 22 | #include <linux/cpu.h> |
8def3103 | 23 | #include <linux/cpufreq.h> |
343a8d17 SH |
24 | #include <linux/cpumask.h> |
25 | #include <linux/cpu_cooling.h> | |
26 | #include <linux/export.h> | |
8def3103 | 27 | #include <linux/module.h> |
343a8d17 | 28 | #include <linux/of_platform.h> |
8def3103 SH |
29 | #include <linux/pm_opp.h> |
30 | #include <linux/scpi_protocol.h> | |
343a8d17 | 31 | #include <linux/slab.h> |
8def3103 SH |
32 | #include <linux/types.h> |
33 | ||
343a8d17 SH |
34 | struct scpi_data { |
35 | struct clk *clk; | |
36 | struct device *cpu_dev; | |
37 | struct thermal_cooling_device *cdev; | |
38 | }; | |
8def3103 SH |
39 | |
40 | static struct scpi_ops *scpi_ops; | |
41 | ||
343a8d17 SH |
42 | static unsigned int scpi_cpufreq_get_rate(unsigned int cpu) |
43 | { | |
44 | struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); | |
45 | struct scpi_data *priv = policy->driver_data; | |
46 | unsigned long rate = clk_get_rate(priv->clk); | |
47 | ||
48 | return rate / 1000; | |
49 | } | |
50 | ||
51 | static int | |
52 | scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) | |
53 | { | |
9326fdf3 | 54 | unsigned long freq = policy->freq_table[index].frequency; |
343a8d17 | 55 | struct scpi_data *priv = policy->driver_data; |
9326fdf3 | 56 | u64 rate = freq * 1000; |
343a8d17 SH |
57 | int ret; |
58 | ||
59 | ret = clk_set_rate(priv->clk, rate); | |
343a8d17 | 60 | |
9326fdf3 DE |
61 | if (ret) |
62 | return ret; | |
63 | ||
64 | if (clk_get_rate(priv->clk) != rate) | |
65 | return -EIO; | |
66 | ||
67 | arch_set_freq_scale(policy->related_cpus, freq, | |
68 | policy->cpuinfo.max_freq); | |
69 | ||
70 | return 0; | |
343a8d17 SH |
71 | } |
72 | ||
73 | static int | |
74 | scpi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) | |
8def3103 | 75 | { |
343a8d17 SH |
76 | int cpu, domain, tdomain; |
77 | struct device *tcpu_dev; | |
78 | ||
79 | domain = scpi_ops->device_domain_id(cpu_dev); | |
80 | if (domain < 0) | |
81 | return domain; | |
82 | ||
83 | for_each_possible_cpu(cpu) { | |
84 | if (cpu == cpu_dev->id) | |
85 | continue; | |
86 | ||
87 | tcpu_dev = get_cpu_device(cpu); | |
88 | if (!tcpu_dev) | |
89 | continue; | |
90 | ||
91 | tdomain = scpi_ops->device_domain_id(tcpu_dev); | |
92 | if (tdomain == domain) | |
93 | cpumask_set_cpu(cpu, cpumask); | |
94 | } | |
95 | ||
96 | return 0; | |
d9975b0b SH |
97 | } |
98 | ||
343a8d17 | 99 | static int scpi_cpufreq_init(struct cpufreq_policy *policy) |
d9975b0b | 100 | { |
c0f2e219 | 101 | int ret; |
343a8d17 SH |
102 | unsigned int latency; |
103 | struct device *cpu_dev; | |
104 | struct scpi_data *priv; | |
105 | struct cpufreq_frequency_table *freq_table; | |
106 | ||
107 | cpu_dev = get_cpu_device(policy->cpu); | |
108 | if (!cpu_dev) { | |
109 | pr_err("failed to get cpu%d device\n", policy->cpu); | |
110 | return -ENODEV; | |
111 | } | |
8def3103 | 112 | |
c0f2e219 SH |
113 | ret = scpi_ops->add_opps_to_device(cpu_dev); |
114 | if (ret) { | |
115 | dev_warn(cpu_dev, "failed to add opps to the device\n"); | |
116 | return ret; | |
8def3103 | 117 | } |
8def3103 | 118 | |
343a8d17 SH |
119 | ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus); |
120 | if (ret) { | |
121 | dev_warn(cpu_dev, "failed to get sharing cpumask\n"); | |
122 | return ret; | |
123 | } | |
124 | ||
125 | ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus); | |
126 | if (ret) { | |
d9975b0b SH |
127 | dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n", |
128 | __func__, ret); | |
343a8d17 SH |
129 | return ret; |
130 | } | |
131 | ||
132 | ret = dev_pm_opp_get_opp_count(cpu_dev); | |
133 | if (ret <= 0) { | |
134 | dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n"); | |
135 | ret = -EPROBE_DEFER; | |
136 | goto out_free_opp; | |
137 | } | |
138 | ||
139 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
140 | if (!priv) { | |
141 | ret = -ENOMEM; | |
142 | goto out_free_opp; | |
143 | } | |
144 | ||
145 | ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table); | |
146 | if (ret) { | |
147 | dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret); | |
148 | goto out_free_priv; | |
149 | } | |
150 | ||
151 | priv->cpu_dev = cpu_dev; | |
152 | priv->clk = clk_get(cpu_dev, NULL); | |
153 | if (IS_ERR(priv->clk)) { | |
154 | dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n", | |
155 | __func__, cpu_dev->id); | |
0725390d | 156 | ret = PTR_ERR(priv->clk); |
343a8d17 SH |
157 | goto out_free_cpufreq_table; |
158 | } | |
159 | ||
160 | policy->driver_data = priv; | |
472ada60 | 161 | policy->freq_table = freq_table; |
343a8d17 SH |
162 | |
163 | /* scpi allows DVFS request for any domain from any CPU */ | |
164 | policy->dvfs_possible_from_any_cpu = true; | |
165 | ||
166 | latency = scpi_ops->get_transition_latency(cpu_dev); | |
167 | if (!latency) | |
168 | latency = CPUFREQ_ETERNAL; | |
169 | ||
170 | policy->cpuinfo.transition_latency = latency; | |
171 | ||
172 | policy->fast_switch_possible = false; | |
173 | return 0; | |
174 | ||
343a8d17 SH |
175 | out_free_cpufreq_table: |
176 | dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); | |
177 | out_free_priv: | |
178 | kfree(priv); | |
179 | out_free_opp: | |
180 | dev_pm_opp_cpumask_remove_table(policy->cpus); | |
181 | ||
d9975b0b | 182 | return ret; |
8def3103 SH |
183 | } |
184 | ||
343a8d17 SH |
185 | static int scpi_cpufreq_exit(struct cpufreq_policy *policy) |
186 | { | |
187 | struct scpi_data *priv = policy->driver_data; | |
188 | ||
189 | cpufreq_cooling_unregister(priv->cdev); | |
190 | clk_put(priv->clk); | |
191 | dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table); | |
192 | kfree(priv); | |
193 | dev_pm_opp_cpumask_remove_table(policy->related_cpus); | |
194 | ||
195 | return 0; | |
196 | } | |
197 | ||
198 | static void scpi_cpufreq_ready(struct cpufreq_policy *policy) | |
199 | { | |
200 | struct scpi_data *priv = policy->driver_data; | |
343a8d17 | 201 | |
eb85c50c | 202 | priv->cdev = of_cpufreq_cooling_register(policy); |
343a8d17 SH |
203 | } |
204 | ||
205 | static struct cpufreq_driver scpi_cpufreq_driver = { | |
206 | .name = "scpi-cpufreq", | |
207 | .flags = CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY | | |
208 | CPUFREQ_NEED_INITIAL_FREQ_CHECK, | |
209 | .verify = cpufreq_generic_frequency_table_verify, | |
210 | .attr = cpufreq_generic_attr, | |
211 | .get = scpi_cpufreq_get_rate, | |
212 | .init = scpi_cpufreq_init, | |
213 | .exit = scpi_cpufreq_exit, | |
214 | .ready = scpi_cpufreq_ready, | |
215 | .target_index = scpi_cpufreq_set_target, | |
8def3103 SH |
216 | }; |
217 | ||
218 | static int scpi_cpufreq_probe(struct platform_device *pdev) | |
219 | { | |
343a8d17 SH |
220 | int ret; |
221 | ||
8def3103 SH |
222 | scpi_ops = get_scpi_ops(); |
223 | if (!scpi_ops) | |
224 | return -EIO; | |
225 | ||
343a8d17 SH |
226 | ret = cpufreq_register_driver(&scpi_cpufreq_driver); |
227 | if (ret) | |
228 | dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n", | |
229 | __func__, ret); | |
230 | return ret; | |
8def3103 SH |
231 | } |
232 | ||
233 | static int scpi_cpufreq_remove(struct platform_device *pdev) | |
234 | { | |
343a8d17 | 235 | cpufreq_unregister_driver(&scpi_cpufreq_driver); |
8def3103 SH |
236 | scpi_ops = NULL; |
237 | return 0; | |
238 | } | |
239 | ||
240 | static struct platform_driver scpi_cpufreq_platdrv = { | |
241 | .driver = { | |
242 | .name = "scpi-cpufreq", | |
8def3103 SH |
243 | }, |
244 | .probe = scpi_cpufreq_probe, | |
245 | .remove = scpi_cpufreq_remove, | |
246 | }; | |
247 | module_platform_driver(scpi_cpufreq_platdrv); | |
248 | ||
249 | MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); | |
250 | MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver"); | |
251 | MODULE_LICENSE("GPL v2"); |