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
27struct 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
37static LIST_HEAD(priv_list);
38
39static 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
45static 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
57static 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 */
69static 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);
98node_put:
99	of_node_put(np);
100	return name;
101}
102
103static 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
148out_clk_put:
149	clk_put(cpu_clk);
150
151	return ret;
152}
153
154static 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
160static 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
169static int cpufreq_exit(struct cpufreq_policy *policy)
170{
171	clk_put(policy->clk);
172	return 0;
173}
174
175static 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
191static 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
292out:
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);
296free_cpumask:
297	free_cpumask_var(priv->cpus);
298	return ret;
299}
300
301static 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
315static 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;
347err:
348	dt_cpufreq_release();
349	return ret;
350}
351
352static void dt_cpufreq_remove(struct platform_device *pdev)
353{
354	cpufreq_unregister_driver(&dt_cpufreq_driver);
355	dt_cpufreq_release();
356}
357
358static 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};
365module_platform_driver(dt_cpufreq_platdrv);
366
367MODULE_ALIAS("platform:cpufreq-dt");
368MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
369MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
370MODULE_DESCRIPTION("Generic cpufreq driver");
371MODULE_LICENSE("GPL");
372