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 opp_table *opp_table;
33	struct opp_table *reg_opp_table;
34	bool have_static_opps;
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 cpufreq_frequency_table *freq_table;
106	struct private_data *priv;
107	struct device *cpu_dev;
108	struct clk *cpu_clk;
109	unsigned int transition_latency;
110	int ret;
111
112	priv = cpufreq_dt_find_data(policy->cpu);
113	if (!priv) {
114		pr_err("failed to find data for cpu%d\n", policy->cpu);
115		return -ENODEV;
116	}
117
118	cpu_dev = priv->cpu_dev;
119	cpumask_copy(policy->cpus, priv->cpus);
120
121	cpu_clk = clk_get(cpu_dev, NULL);
122	if (IS_ERR(cpu_clk)) {
123		ret = PTR_ERR(cpu_clk);
124		dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
125		return ret;
126	}
127
128	/*
129	 * Initialize OPP tables for all policy->cpus. They will be shared by
130	 * all CPUs which have marked their CPUs shared with OPP bindings.
131	 *
132	 * For platforms not using operating-points-v2 bindings, we do this
133	 * before updating policy->cpus. Otherwise, we will end up creating
134	 * duplicate OPPs for policy->cpus.
135	 *
136	 * OPPs might be populated at runtime, don't check for error here
137	 */
138	if (!dev_pm_opp_of_cpumask_add_table(policy->cpus))
139		priv->have_static_opps = true;
140
141	/*
142	 * But we need OPP table to function so if it is not there let's
143	 * give platform code chance to provide it for us.
144	 */
145	ret = dev_pm_opp_get_opp_count(cpu_dev);
146	if (ret <= 0) {
147		dev_err(cpu_dev, "OPP table can't be empty\n");
148		ret = -ENODEV;
149		goto out_free_opp;
150	}
151
152	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
153	if (ret) {
154		dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
155		goto out_free_opp;
156	}
157
158	policy->driver_data = priv;
159	policy->clk = cpu_clk;
160	policy->freq_table = freq_table;
161
162	policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
163
164	/* Support turbo/boost mode */
165	if (policy_has_boost_freq(policy)) {
166		/* This gets disabled by core on driver unregister */
167		ret = cpufreq_enable_boost_support();
168		if (ret)
169			goto out_free_cpufreq_table;
170		cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
171	}
172
173	transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
174	if (!transition_latency)
175		transition_latency = CPUFREQ_ETERNAL;
176
177	policy->cpuinfo.transition_latency = transition_latency;
178	policy->dvfs_possible_from_any_cpu = true;
179
180	dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
181
182	return 0;
183
184out_free_cpufreq_table:
185	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
186out_free_opp:
187	if (priv->have_static_opps)
188		dev_pm_opp_of_cpumask_remove_table(policy->cpus);
189	clk_put(cpu_clk);
190
191	return ret;
192}
193
194static int cpufreq_online(struct cpufreq_policy *policy)
195{
196	/* We did light-weight tear down earlier, nothing to do here */
197	return 0;
198}
199
200static int cpufreq_offline(struct cpufreq_policy *policy)
201{
202	/*
203	 * Preserve policy->driver_data and don't free resources on light-weight
204	 * tear down.
205	 */
206	return 0;
207}
208
209static int cpufreq_exit(struct cpufreq_policy *policy)
210{
211	struct private_data *priv = policy->driver_data;
212
213	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
214	if (priv->have_static_opps)
215		dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
216	clk_put(policy->clk);
217	return 0;
218}
219
220static struct cpufreq_driver dt_cpufreq_driver = {
221	.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
222		 CPUFREQ_IS_COOLING_DEV,
223	.verify = cpufreq_generic_frequency_table_verify,
224	.target_index = set_target,
225	.get = cpufreq_generic_get,
226	.init = cpufreq_init,
227	.exit = cpufreq_exit,
228	.online = cpufreq_online,
229	.offline = cpufreq_offline,
230	.name = "cpufreq-dt",
231	.attr = cpufreq_dt_attr,
232	.suspend = cpufreq_generic_suspend,
233};
234
235static int dt_cpufreq_early_init(struct device *dev, int cpu)
236{
237	struct private_data *priv;
238	struct device *cpu_dev;
239	const char *reg_name;
240	int ret;
241
242	/* Check if this CPU is already covered by some other policy */
243	if (cpufreq_dt_find_data(cpu))
244		return 0;
245
246	cpu_dev = get_cpu_device(cpu);
247	if (!cpu_dev)
248		return -EPROBE_DEFER;
249
250	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
251	if (!priv)
252		return -ENOMEM;
253
254	if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
255		return -ENOMEM;
256
257	priv->cpu_dev = cpu_dev;
258
259	/* Try to get OPP table early to ensure resources are available */
260	priv->opp_table = dev_pm_opp_get_opp_table(cpu_dev);
261	if (IS_ERR(priv->opp_table)) {
262		ret = PTR_ERR(priv->opp_table);
263		if (ret != -EPROBE_DEFER)
264			dev_err(cpu_dev, "failed to get OPP table: %d\n", ret);
265		goto free_cpumask;
266	}
267
268	/*
269	 * OPP layer will be taking care of regulators now, but it needs to know
270	 * the name of the regulator first.
271	 */
272	reg_name = find_supply_name(cpu_dev);
273	if (reg_name) {
274		priv->reg_opp_table = dev_pm_opp_set_regulators(cpu_dev,
275								&reg_name, 1);
276		if (IS_ERR(priv->reg_opp_table)) {
277			ret = PTR_ERR(priv->reg_opp_table);
278			if (ret != -EPROBE_DEFER)
279				dev_err(cpu_dev, "failed to set regulators: %d\n",
280					ret);
281			goto put_table;
282		}
283	}
284
285	/* Find OPP sharing information so we can fill pri->cpus here */
286	/* Get OPP-sharing information from "operating-points-v2" bindings */
287	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
288	if (ret) {
289		if (ret != -ENOENT)
290			goto put_reg;
291
292		/*
293		 * operating-points-v2 not supported, fallback to all CPUs share
294		 * OPP for backward compatibility if the platform hasn't set
295		 * sharing CPUs.
296		 */
297		if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus)) {
298			cpumask_setall(priv->cpus);
299
300			/*
301			 * OPP tables are initialized only for cpu, do it for
302			 * others as well.
303			 */
304			ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
305			if (ret)
306				dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
307					__func__, ret);
308		}
309	}
310
311	list_add(&priv->node, &priv_list);
312	return 0;
313
314put_reg:
315	if (priv->reg_opp_table)
316		dev_pm_opp_put_regulators(priv->reg_opp_table);
317put_table:
318	dev_pm_opp_put_opp_table(priv->opp_table);
319free_cpumask:
320	free_cpumask_var(priv->cpus);
321	return ret;
322}
323
324static void dt_cpufreq_release(void)
325{
326	struct private_data *priv, *tmp;
327
328	list_for_each_entry_safe(priv, tmp, &priv_list, node) {
329		if (priv->reg_opp_table)
330			dev_pm_opp_put_regulators(priv->reg_opp_table);
331		dev_pm_opp_put_opp_table(priv->opp_table);
332		free_cpumask_var(priv->cpus);
333		list_del(&priv->node);
334	}
335}
336
337static int dt_cpufreq_probe(struct platform_device *pdev)
338{
339	struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
340	int ret, cpu;
341
342	/* Request resources early so we can return in case of -EPROBE_DEFER */
343	for_each_possible_cpu(cpu) {
344		ret = dt_cpufreq_early_init(&pdev->dev, cpu);
345		if (ret)
346			goto err;
347	}
348
349	if (data) {
350		if (data->have_governor_per_policy)
351			dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
352
353		dt_cpufreq_driver.resume = data->resume;
354		if (data->suspend)
355			dt_cpufreq_driver.suspend = data->suspend;
356		if (data->get_intermediate) {
357			dt_cpufreq_driver.target_intermediate = data->target_intermediate;
358			dt_cpufreq_driver.get_intermediate = data->get_intermediate;
359		}
360	}
361
362	ret = cpufreq_register_driver(&dt_cpufreq_driver);
363	if (ret) {
364		dev_err(&pdev->dev, "failed register driver: %d\n", ret);
365		goto err;
366	}
367
368	return 0;
369err:
370	dt_cpufreq_release();
371	return ret;
372}
373
374static int dt_cpufreq_remove(struct platform_device *pdev)
375{
376	cpufreq_unregister_driver(&dt_cpufreq_driver);
377	dt_cpufreq_release();
378	return 0;
379}
380
381static struct platform_driver dt_cpufreq_platdrv = {
382	.driver = {
383		.name	= "cpufreq-dt",
384	},
385	.probe		= dt_cpufreq_probe,
386	.remove		= dt_cpufreq_remove,
387};
388module_platform_driver(dt_cpufreq_platdrv);
389
390MODULE_ALIAS("platform:cpufreq-dt");
391MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
392MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
393MODULE_DESCRIPTION("Generic cpufreq driver");
394MODULE_LICENSE("GPL");
395