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 cpufreq_frequency_table *freq_table;
33 bool have_static_opps;
34 int opp_token;
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[] = { NULL, NULL };
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 (!zalloc_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[0] = find_supply_name(cpu_dev);
222 if (reg_name[0]) {
223 priv->opp_token = dev_pm_opp_set_regulators(cpu_dev, reg_name);
224 if (priv->opp_token < 0) {
225 ret = dev_err_probe(cpu_dev, priv->opp_token,
226 "failed to set regulators\n");
227 goto free_cpumask;
228 }
229 }
230
231 /* Get OPP-sharing information from "operating-points-v2" bindings */
232 ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
233 if (ret) {
234 if (ret != -ENOENT)
235 goto out;
236
237 /*
238 * operating-points-v2 not supported, fallback to all CPUs share
239 * OPP for backward compatibility if the platform hasn't set
240 * sharing CPUs.
241 */
242 if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus))
243 fallback = true;
244 }
245
246 /*
247 * Initialize OPP tables for all priv->cpus. They will be shared by
248 * all CPUs which have marked their CPUs shared with OPP bindings.
249 *
250 * For platforms not using operating-points-v2 bindings, we do this
251 * before updating priv->cpus. Otherwise, we will end up creating
252 * duplicate OPPs for the CPUs.
253 *
254 * OPPs might be populated at runtime, don't fail for error here unless
255 * it is -EPROBE_DEFER.
256 */
257 ret = dev_pm_opp_of_cpumask_add_table(priv->cpus);
258 if (!ret) {
259 priv->have_static_opps = true;
260 } else if (ret == -EPROBE_DEFER) {
261 goto out;
262 }
263
264 /*
265 * The OPP table must be initialized, statically or dynamically, by this
266 * point.
267 */
268 ret = dev_pm_opp_get_opp_count(cpu_dev);
269 if (ret <= 0) {
270 dev_err(cpu_dev, "OPP table can't be empty\n");
271 ret = -ENODEV;
272 goto out;
273 }
274
275 if (fallback) {
276 cpumask_setall(priv->cpus);
277 ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
278 if (ret)
279 dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
280 __func__, ret);
281 }
282
283 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &priv->freq_table);
284 if (ret) {
285 dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
286 goto out;
287 }
288
289 list_add(&priv->node, &priv_list);
290 return 0;
291
292 out:
293 if (priv->have_static_opps)
294 dev_pm_opp_of_cpumask_remove_table(priv->cpus);
295 dev_pm_opp_put_regulators(priv->opp_token);
296 free_cpumask:
297 free_cpumask_var(priv->cpus);
298 return ret;
299 }
300
dt_cpufreq_release(void)301 static void dt_cpufreq_release(void)
302 {
303 struct private_data *priv, *tmp;
304
305 list_for_each_entry_safe(priv, tmp, &priv_list, node) {
306 dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &priv->freq_table);
307 if (priv->have_static_opps)
308 dev_pm_opp_of_cpumask_remove_table(priv->cpus);
309 dev_pm_opp_put_regulators(priv->opp_token);
310 free_cpumask_var(priv->cpus);
311 list_del(&priv->node);
312 }
313 }
314
dt_cpufreq_probe(struct platform_device * pdev)315 static int dt_cpufreq_probe(struct platform_device *pdev)
316 {
317 struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
318 int ret, cpu;
319
320 /* Request resources early so we can return in case of -EPROBE_DEFER */
321 for_each_possible_cpu(cpu) {
322 ret = dt_cpufreq_early_init(&pdev->dev, cpu);
323 if (ret)
324 goto err;
325 }
326
327 if (data) {
328 if (data->have_governor_per_policy)
329 dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
330
331 dt_cpufreq_driver.resume = data->resume;
332 if (data->suspend)
333 dt_cpufreq_driver.suspend = data->suspend;
334 if (data->get_intermediate) {
335 dt_cpufreq_driver.target_intermediate = data->target_intermediate;
336 dt_cpufreq_driver.get_intermediate = data->get_intermediate;
337 }
338 }
339
340 ret = cpufreq_register_driver(&dt_cpufreq_driver);
341 if (ret) {
342 dev_err(&pdev->dev, "failed register driver: %d\n", ret);
343 goto err;
344 }
345
346 return 0;
347 err:
348 dt_cpufreq_release();
349 return ret;
350 }
351
dt_cpufreq_remove(struct platform_device * pdev)352 static void dt_cpufreq_remove(struct platform_device *pdev)
353 {
354 cpufreq_unregister_driver(&dt_cpufreq_driver);
355 dt_cpufreq_release();
356 }
357
358 static struct platform_driver dt_cpufreq_platdrv = {
359 .driver = {
360 .name = "cpufreq-dt",
361 },
362 .probe = dt_cpufreq_probe,
363 .remove_new = dt_cpufreq_remove,
364 };
365 module_platform_driver(dt_cpufreq_platdrv);
366
367 MODULE_ALIAS("platform:cpufreq-dt");
368 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
369 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
370 MODULE_DESCRIPTION("Generic cpufreq driver");
371 MODULE_LICENSE("GPL");
372