1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2012 Freescale Semiconductor, Inc.
4 *
5 * Copyright (C) 2014 Linaro.
6 * Viresh Kumar <viresh.kumar@linaro.org>
7 */
8
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11 #include <linux/clk.h>
12 #include <linux/cpu.h>
13 #include <linux/cpufreq.h>
14 #include <linux/cpumask.h>
15 #include <linux/err.h>
16 #include <linux/list.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/pm_opp.h>
20 #include <linux/platform_device.h>
21 #include <linux/regulator/consumer.h>
22 #include <linux/slab.h>
23 #include <linux/thermal.h>
24
25 #include "cpufreq-dt.h"
26
27 struct private_data {
28 struct list_head node;
29
30 cpumask_var_t cpus;
31 struct device *cpu_dev;
32 struct opp_table *opp_table;
33 struct cpufreq_frequency_table *freq_table;
34 bool have_static_opps;
35 };
36
37 static LIST_HEAD(priv_list);
38
39 static struct freq_attr *cpufreq_dt_attr[] = {
40 &cpufreq_freq_attr_scaling_available_freqs,
41 NULL, /* Extra space for boost-attr if required */
42 NULL,
43 };
44
cpufreq_dt_find_data(int cpu)45 static struct private_data *cpufreq_dt_find_data(int cpu)
46 {
47 struct private_data *priv;
48
49 list_for_each_entry(priv, &priv_list, node) {
50 if (cpumask_test_cpu(cpu, priv->cpus))
51 return priv;
52 }
53
54 return NULL;
55 }
56
set_target(struct cpufreq_policy * policy,unsigned int index)57 static int set_target(struct cpufreq_policy *policy, unsigned int index)
58 {
59 struct private_data *priv = policy->driver_data;
60 unsigned long freq = policy->freq_table[index].frequency;
61
62 return dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000);
63 }
64
65 /*
66 * An earlier version of opp-v1 bindings used to name the regulator
67 * "cpu0-supply", we still need to handle that for backwards compatibility.
68 */
find_supply_name(struct device * dev)69 static const char *find_supply_name(struct device *dev)
70 {
71 struct device_node *np;
72 struct property *pp;
73 int cpu = dev->id;
74 const char *name = NULL;
75
76 np = of_node_get(dev->of_node);
77
78 /* This must be valid for sure */
79 if (WARN_ON(!np))
80 return NULL;
81
82 /* Try "cpu0" for older DTs */
83 if (!cpu) {
84 pp = of_find_property(np, "cpu0-supply", NULL);
85 if (pp) {
86 name = "cpu0";
87 goto node_put;
88 }
89 }
90
91 pp = of_find_property(np, "cpu-supply", NULL);
92 if (pp) {
93 name = "cpu";
94 goto node_put;
95 }
96
97 dev_dbg(dev, "no regulator for cpu%d\n", cpu);
98 node_put:
99 of_node_put(np);
100 return name;
101 }
102
cpufreq_init(struct cpufreq_policy * policy)103 static int cpufreq_init(struct cpufreq_policy *policy)
104 {
105 struct private_data *priv;
106 struct device *cpu_dev;
107 struct clk *cpu_clk;
108 unsigned int transition_latency;
109 int ret;
110
111 priv = cpufreq_dt_find_data(policy->cpu);
112 if (!priv) {
113 pr_err("failed to find data for cpu%d\n", policy->cpu);
114 return -ENODEV;
115 }
116 cpu_dev = priv->cpu_dev;
117
118 cpu_clk = clk_get(cpu_dev, NULL);
119 if (IS_ERR(cpu_clk)) {
120 ret = PTR_ERR(cpu_clk);
121 dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
122 return ret;
123 }
124
125 transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
126 if (!transition_latency)
127 transition_latency = CPUFREQ_ETERNAL;
128
129 cpumask_copy(policy->cpus, priv->cpus);
130 policy->driver_data = priv;
131 policy->clk = cpu_clk;
132 policy->freq_table = priv->freq_table;
133 policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
134 policy->cpuinfo.transition_latency = transition_latency;
135 policy->dvfs_possible_from_any_cpu = true;
136
137 /* Support turbo/boost mode */
138 if (policy_has_boost_freq(policy)) {
139 /* This gets disabled by core on driver unregister */
140 ret = cpufreq_enable_boost_support();
141 if (ret)
142 goto out_clk_put;
143 cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
144 }
145
146 return 0;
147
148 out_clk_put:
149 clk_put(cpu_clk);
150
151 return ret;
152 }
153
cpufreq_online(struct cpufreq_policy * policy)154 static int cpufreq_online(struct cpufreq_policy *policy)
155 {
156 /* We did light-weight tear down earlier, nothing to do here */
157 return 0;
158 }
159
cpufreq_offline(struct cpufreq_policy * policy)160 static int cpufreq_offline(struct cpufreq_policy *policy)
161 {
162 /*
163 * Preserve policy->driver_data and don't free resources on light-weight
164 * tear down.
165 */
166 return 0;
167 }
168
cpufreq_exit(struct cpufreq_policy * policy)169 static int cpufreq_exit(struct cpufreq_policy *policy)
170 {
171 clk_put(policy->clk);
172 return 0;
173 }
174
175 static struct cpufreq_driver dt_cpufreq_driver = {
176 .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
177 CPUFREQ_IS_COOLING_DEV,
178 .verify = cpufreq_generic_frequency_table_verify,
179 .target_index = set_target,
180 .get = cpufreq_generic_get,
181 .init = cpufreq_init,
182 .exit = cpufreq_exit,
183 .online = cpufreq_online,
184 .offline = cpufreq_offline,
185 .register_em = cpufreq_register_em_with_opp,
186 .name = "cpufreq-dt",
187 .attr = cpufreq_dt_attr,
188 .suspend = cpufreq_generic_suspend,
189 };
190
dt_cpufreq_early_init(struct device * dev,int cpu)191 static int dt_cpufreq_early_init(struct device *dev, int cpu)
192 {
193 struct private_data *priv;
194 struct device *cpu_dev;
195 bool fallback = false;
196 const char *reg_name;
197 int ret;
198
199 /* Check if this CPU is already covered by some other policy */
200 if (cpufreq_dt_find_data(cpu))
201 return 0;
202
203 cpu_dev = get_cpu_device(cpu);
204 if (!cpu_dev)
205 return -EPROBE_DEFER;
206
207 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
208 if (!priv)
209 return -ENOMEM;
210
211 if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
212 return -ENOMEM;
213
214 cpumask_set_cpu(cpu, priv->cpus);
215 priv->cpu_dev = cpu_dev;
216
217 /*
218 * OPP layer will be taking care of regulators now, but it needs to know
219 * the name of the regulator first.
220 */
221 reg_name = find_supply_name(cpu_dev);
222 if (reg_name) {
223 priv->opp_table = dev_pm_opp_set_regulators(cpu_dev, ®_name,
224 1);
225 if (IS_ERR(priv->opp_table)) {
226 ret = PTR_ERR(priv->opp_table);
227 if (ret != -EPROBE_DEFER)
228 dev_err(cpu_dev, "failed to set regulators: %d\n",
229 ret);
230 goto free_cpumask;
231 }
232 }
233
234 /* Get OPP-sharing information from "operating-points-v2" bindings */
235 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
236 if (ret) {
237 if (ret != -ENOENT)
238 goto out;
239
240 /*
241 * operating-points-v2 not supported, fallback to all CPUs share
242 * OPP for backward compatibility if the platform hasn't set
243 * sharing CPUs.
244 */
245 if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus))
246 fallback = true;
247 }
248
249 /*
250 * Initialize OPP tables for all priv->cpus. They will be shared by
251 * all CPUs which have marked their CPUs shared with OPP bindings.
252 *
253 * For platforms not using operating-points-v2 bindings, we do this
254 * before updating priv->cpus. Otherwise, we will end up creating
255 * duplicate OPPs for the CPUs.
256 *
257 * OPPs might be populated at runtime, don't fail for error here unless
258 * it is -EPROBE_DEFER.
259 */
260 ret = dev_pm_opp_of_cpumask_add_table(priv->cpus);
261 if (!ret) {
262 priv->have_static_opps = true;
263 } else if (ret == -EPROBE_DEFER) {
264 goto out;
265 }
266
267 /*
268 * The OPP table must be initialized, statically or dynamically, by this
269 * point.
270 */
271 ret = dev_pm_opp_get_opp_count(cpu_dev);
272 if (ret <= 0) {
273 dev_err(cpu_dev, "OPP table can't be empty\n");
274 ret = -ENODEV;
275 goto out;
276 }
277
278 if (fallback) {
279 cpumask_setall(priv->cpus);
280 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
281 if (ret)
282 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
283 __func__, ret);
284 }
285
286 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &priv->freq_table);
287 if (ret) {
288 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
289 goto out;
290 }
291
292 list_add(&priv->node, &priv_list);
293 return 0;
294
295 out:
296 if (priv->have_static_opps)
297 dev_pm_opp_of_cpumask_remove_table(priv->cpus);
298 dev_pm_opp_put_regulators(priv->opp_table);
299 free_cpumask:
300 free_cpumask_var(priv->cpus);
301 return ret;
302 }
303
dt_cpufreq_release(void)304 static void dt_cpufreq_release(void)
305 {
306 struct private_data *priv, *tmp;
307
308 list_for_each_entry_safe(priv, tmp, &priv_list, node) {
309 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &priv->freq_table);
310 if (priv->have_static_opps)
311 dev_pm_opp_of_cpumask_remove_table(priv->cpus);
312 dev_pm_opp_put_regulators(priv->opp_table);
313 free_cpumask_var(priv->cpus);
314 list_del(&priv->node);
315 }
316 }
317
dt_cpufreq_probe(struct platform_device * pdev)318 static int dt_cpufreq_probe(struct platform_device *pdev)
319 {
320 struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
321 int ret, cpu;
322
323 /* Request resources early so we can return in case of -EPROBE_DEFER */
324 for_each_possible_cpu(cpu) {
325 ret = dt_cpufreq_early_init(&pdev->dev, cpu);
326 if (ret)
327 goto err;
328 }
329
330 if (data) {
331 if (data->have_governor_per_policy)
332 dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
333
334 dt_cpufreq_driver.resume = data->resume;
335 if (data->suspend)
336 dt_cpufreq_driver.suspend = data->suspend;
337 if (data->get_intermediate) {
338 dt_cpufreq_driver.target_intermediate = data->target_intermediate;
339 dt_cpufreq_driver.get_intermediate = data->get_intermediate;
340 }
341 }
342
343 ret = cpufreq_register_driver(&dt_cpufreq_driver);
344 if (ret) {
345 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
346 goto err;
347 }
348
349 return 0;
350 err:
351 dt_cpufreq_release();
352 return ret;
353 }
354
dt_cpufreq_remove(struct platform_device * pdev)355 static int dt_cpufreq_remove(struct platform_device *pdev)
356 {
357 cpufreq_unregister_driver(&dt_cpufreq_driver);
358 dt_cpufreq_release();
359 return 0;
360 }
361
362 static struct platform_driver dt_cpufreq_platdrv = {
363 .driver = {
364 .name = "cpufreq-dt",
365 },
366 .probe = dt_cpufreq_probe,
367 .remove = dt_cpufreq_remove,
368 };
369 module_platform_driver(dt_cpufreq_platdrv);
370
371 MODULE_ALIAS("platform:cpufreq-dt");
372 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
373 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
374 MODULE_DESCRIPTION("Generic cpufreq driver");
375 MODULE_LICENSE("GPL");
376