1/*
  2 * Copyright (C) 2012 Freescale Semiconductor, Inc.
  3 *
  4 * Copyright (C) 2014 Linaro.
  5 * Viresh Kumar <viresh.kumar@linaro.org>
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 */
 11
 12#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
 13
 14#include <linux/clk.h>
 15#include <linux/cpu.h>
 16#include <linux/cpu_cooling.h>
 17#include <linux/cpufreq.h>
 18#include <linux/cpumask.h>
 19#include <linux/err.h>
 20#include <linux/module.h>
 21#include <linux/of.h>
 22#include <linux/pm_opp.h>
 23#include <linux/platform_device.h>
 24#include <linux/regulator/consumer.h>
 25#include <linux/slab.h>
 26#include <linux/thermal.h>
 27
 28#include "cpufreq-dt.h"
 29
 30struct private_data {
 31	struct opp_table *opp_table;
 32	struct device *cpu_dev;
 33	struct thermal_cooling_device *cdev;
 34	const char *reg_name;
 35};
 36
 37static struct freq_attr *cpufreq_dt_attr[] = {
 38	&cpufreq_freq_attr_scaling_available_freqs,
 39	NULL,   /* Extra space for boost-attr if required */
 40	NULL,
 41};
 42
 43static int set_target(struct cpufreq_policy *policy, unsigned int index)
 44{
 45	struct private_data *priv = policy->driver_data;
 46	unsigned long freq = policy->freq_table[index].frequency;
 47	int ret;
 48
 49	ret = dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000);
 50
 51	if (!ret) {
 52		arch_set_freq_scale(policy->related_cpus, freq,
 53				    policy->cpuinfo.max_freq);
 54	}
 55
 56	return ret;
 57}
 58
 59/*
 60 * An earlier version of opp-v1 bindings used to name the regulator
 61 * "cpu0-supply", we still need to handle that for backwards compatibility.
 62 */
 63static const char *find_supply_name(struct device *dev)
 64{
 65	struct device_node *np;
 66	struct property *pp;
 67	int cpu = dev->id;
 68	const char *name = NULL;
 69
 70	np = of_node_get(dev->of_node);
 71
 72	/* This must be valid for sure */
 73	if (WARN_ON(!np))
 74		return NULL;
 75
 76	/* Try "cpu0" for older DTs */
 77	if (!cpu) {
 78		pp = of_find_property(np, "cpu0-supply", NULL);
 79		if (pp) {
 80			name = "cpu0";
 81			goto node_put;
 82		}
 83	}
 84
 85	pp = of_find_property(np, "cpu-supply", NULL);
 86	if (pp) {
 87		name = "cpu";
 88		goto node_put;
 89	}
 90
 91	dev_dbg(dev, "no regulator for cpu%d\n", cpu);
 92node_put:
 93	of_node_put(np);
 94	return name;
 95}
 96
 97static int resources_available(void)
 98{
 99	struct device *cpu_dev;
100	struct regulator *cpu_reg;
101	struct clk *cpu_clk;
102	int ret = 0;
103	const char *name;
104
105	cpu_dev = get_cpu_device(0);
106	if (!cpu_dev) {
107		pr_err("failed to get cpu0 device\n");
108		return -ENODEV;
109	}
110
111	cpu_clk = clk_get(cpu_dev, NULL);
112	ret = PTR_ERR_OR_ZERO(cpu_clk);
113	if (ret) {
114		/*
115		 * If cpu's clk node is present, but clock is not yet
116		 * registered, we should try defering probe.
117		 */
118		if (ret == -EPROBE_DEFER)
119			dev_dbg(cpu_dev, "clock not ready, retry\n");
120		else
121			dev_err(cpu_dev, "failed to get clock: %d\n", ret);
122
123		return ret;
124	}
125
126	clk_put(cpu_clk);
127
128	name = find_supply_name(cpu_dev);
129	/* Platform doesn't require regulator */
130	if (!name)
131		return 0;
132
133	cpu_reg = regulator_get_optional(cpu_dev, name);
134	ret = PTR_ERR_OR_ZERO(cpu_reg);
135	if (ret) {
136		/*
137		 * If cpu's regulator supply node is present, but regulator is
138		 * not yet registered, we should try defering probe.
139		 */
140		if (ret == -EPROBE_DEFER)
141			dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n");
142		else
143			dev_dbg(cpu_dev, "no regulator for cpu0: %d\n", ret);
144
145		return ret;
146	}
147
148	regulator_put(cpu_reg);
149	return 0;
150}
151
152static int cpufreq_init(struct cpufreq_policy *policy)
153{
154	struct cpufreq_frequency_table *freq_table;
155	struct opp_table *opp_table = NULL;
156	struct private_data *priv;
157	struct device *cpu_dev;
158	struct clk *cpu_clk;
159	unsigned int transition_latency;
160	bool fallback = false;
161	const char *name;
162	int ret;
163
164	cpu_dev = get_cpu_device(policy->cpu);
165	if (!cpu_dev) {
166		pr_err("failed to get cpu%d device\n", policy->cpu);
167		return -ENODEV;
168	}
169
170	cpu_clk = clk_get(cpu_dev, NULL);
171	if (IS_ERR(cpu_clk)) {
172		ret = PTR_ERR(cpu_clk);
173		dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
174		return ret;
175	}
176
177	/* Get OPP-sharing information from "operating-points-v2" bindings */
178	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
179	if (ret) {
180		if (ret != -ENOENT)
181			goto out_put_clk;
182
183		/*
184		 * operating-points-v2 not supported, fallback to old method of
185		 * finding shared-OPPs for backward compatibility if the
186		 * platform hasn't set sharing CPUs.
187		 */
188		if (dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus))
189			fallback = true;
190	}
191
192	/*
193	 * OPP layer will be taking care of regulators now, but it needs to know
194	 * the name of the regulator first.
195	 */
196	name = find_supply_name(cpu_dev);
197	if (name) {
198		opp_table = dev_pm_opp_set_regulators(cpu_dev, &name, 1);
199		if (IS_ERR(opp_table)) {
200			ret = PTR_ERR(opp_table);
201			dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
202				policy->cpu, ret);
203			goto out_put_clk;
204		}
205	}
206
207	/*
208	 * Initialize OPP tables for all policy->cpus. They will be shared by
209	 * all CPUs which have marked their CPUs shared with OPP bindings.
210	 *
211	 * For platforms not using operating-points-v2 bindings, we do this
212	 * before updating policy->cpus. Otherwise, we will end up creating
213	 * duplicate OPPs for policy->cpus.
214	 *
215	 * OPPs might be populated at runtime, don't check for error here
216	 */
217	dev_pm_opp_of_cpumask_add_table(policy->cpus);
218
219	/*
220	 * But we need OPP table to function so if it is not there let's
221	 * give platform code chance to provide it for us.
222	 */
223	ret = dev_pm_opp_get_opp_count(cpu_dev);
224	if (ret <= 0) {
225		dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
226		ret = -EPROBE_DEFER;
227		goto out_free_opp;
228	}
229
230	if (fallback) {
231		cpumask_setall(policy->cpus);
232
233		/*
234		 * OPP tables are initialized only for policy->cpu, do it for
235		 * others as well.
236		 */
237		ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
238		if (ret)
239			dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
240				__func__, ret);
241	}
242
243	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
244	if (!priv) {
245		ret = -ENOMEM;
246		goto out_free_opp;
247	}
248
249	priv->reg_name = name;
250	priv->opp_table = opp_table;
251
252	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
253	if (ret) {
254		dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
255		goto out_free_priv;
256	}
257
258	priv->cpu_dev = cpu_dev;
259	policy->driver_data = priv;
260	policy->clk = cpu_clk;
261	policy->freq_table = freq_table;
262
263	policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
264
265	/* Support turbo/boost mode */
266	if (policy_has_boost_freq(policy)) {
267		/* This gets disabled by core on driver unregister */
268		ret = cpufreq_enable_boost_support();
269		if (ret)
270			goto out_free_cpufreq_table;
271		cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
272	}
273
274	transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
275	if (!transition_latency)
276		transition_latency = CPUFREQ_ETERNAL;
277
278	policy->cpuinfo.transition_latency = transition_latency;
279	policy->dvfs_possible_from_any_cpu = true;
280
281	return 0;
282
283out_free_cpufreq_table:
284	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
285out_free_priv:
286	kfree(priv);
287out_free_opp:
288	dev_pm_opp_of_cpumask_remove_table(policy->cpus);
289	if (name)
290		dev_pm_opp_put_regulators(opp_table);
291out_put_clk:
292	clk_put(cpu_clk);
293
294	return ret;
295}
296
297static int cpufreq_exit(struct cpufreq_policy *policy)
298{
299	struct private_data *priv = policy->driver_data;
300
301	cpufreq_cooling_unregister(priv->cdev);
302	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
303	dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
304	if (priv->reg_name)
305		dev_pm_opp_put_regulators(priv->opp_table);
306
307	clk_put(policy->clk);
308	kfree(priv);
309
310	return 0;
311}
312
313static void cpufreq_ready(struct cpufreq_policy *policy)
314{
315	struct private_data *priv = policy->driver_data;
316
317	priv->cdev = of_cpufreq_cooling_register(policy);
318}
319
320static struct cpufreq_driver dt_cpufreq_driver = {
321	.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
322	.verify = cpufreq_generic_frequency_table_verify,
323	.target_index = set_target,
324	.get = cpufreq_generic_get,
325	.init = cpufreq_init,
326	.exit = cpufreq_exit,
327	.ready = cpufreq_ready,
328	.name = "cpufreq-dt",
329	.attr = cpufreq_dt_attr,
330	.suspend = cpufreq_generic_suspend,
331};
332
333static int dt_cpufreq_probe(struct platform_device *pdev)
334{
335	struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
336	int ret;
337
338	/*
339	 * All per-cluster (CPUs sharing clock/voltages) initialization is done
340	 * from ->init(). In probe(), we just need to make sure that clk and
341	 * regulators are available. Else defer probe and retry.
342	 *
343	 * FIXME: Is checking this only for CPU0 sufficient ?
344	 */
345	ret = resources_available();
346	if (ret)
347		return ret;
348
349	if (data && data->have_governor_per_policy)
350		dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
351
352	ret = cpufreq_register_driver(&dt_cpufreq_driver);
353	if (ret)
354		dev_err(&pdev->dev, "failed register driver: %d\n", ret);
355
356	return ret;
357}
358
359static int dt_cpufreq_remove(struct platform_device *pdev)
360{
361	cpufreq_unregister_driver(&dt_cpufreq_driver);
362	return 0;
363}
364
365static struct platform_driver dt_cpufreq_platdrv = {
366	.driver = {
367		.name	= "cpufreq-dt",
368	},
369	.probe		= dt_cpufreq_probe,
370	.remove		= dt_cpufreq_remove,
371};
372module_platform_driver(dt_cpufreq_platdrv);
373
374MODULE_ALIAS("platform:cpufreq-dt");
375MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
376MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
377MODULE_DESCRIPTION("Generic cpufreq driver");
378MODULE_LICENSE("GPL");