[linux-2.6-block.git] / drivers / cpufreq / cpufreq-cpu0.c

/*
 * Copyright (C) 2012 Freescale Semiconductor, Inc.
 *
 * The OPP code in function cpu0_set_target() is reused from
 * drivers/cpufreq/omap-cpufreq.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/opp.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

static unsigned int transition_latency;
static unsigned int voltage_tolerance; /* in percentage */

static struct device *cpu_dev;
static struct clk *cpu_clk;
static struct regulator *cpu_reg;
static struct cpufreq_frequency_table *freq_table;

static int cpu0_verify_speed(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, freq_table);
}

static unsigned int cpu0_get_speed(unsigned int cpu)
{
	return clk_get_rate(cpu_clk) / 1000;
}

static int cpu0_set_target(struct cpufreq_policy *policy,
			   unsigned int target_freq, unsigned int relation)
{
	struct cpufreq_freqs freqs;
	struct opp *opp;
	unsigned long freq_Hz, volt = 0, volt_old = 0, tol = 0;
	unsigned int index, cpu;
	int ret;

	ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
					     relation, &index);
	if (ret) {
		pr_err("failed to match target freqency %d: %d\n",
		       target_freq, ret);
		return ret;
	}

	freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
	if (freq_Hz < 0)
		freq_Hz = freq_table[index].frequency * 1000;
	freqs.new = freq_Hz / 1000;
	freqs.old = clk_get_rate(cpu_clk) / 1000;

	if (freqs.old == freqs.new)
		return 0;

	for_each_online_cpu(cpu) {
		freqs.cpu = cpu;
		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	}

	if (cpu_reg) {
		opp = opp_find_freq_ceil(cpu_dev, &freq_Hz);
		if (IS_ERR(opp)) {
			pr_err("failed to find OPP for %ld\n", freq_Hz);
			return PTR_ERR(opp);
		}
		volt = opp_get_voltage(opp);
		tol = volt * voltage_tolerance / 100;
		volt_old = regulator_get_voltage(cpu_reg);
	}

	pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
		 freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
		 freqs.new / 1000, volt ? volt / 1000 : -1);

	/* scaling up?  scale voltage before frequency */
	if (cpu_reg && freqs.new > freqs.old) {
		ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
		if (ret) {
			pr_err("failed to scale voltage up: %d\n", ret);
			freqs.new = freqs.old;
			return ret;
		}
	}

	ret = clk_set_rate(cpu_clk, freqs.new * 1000);
	if (ret) {
		pr_err("failed to set clock rate: %d\n", ret);
		if (cpu_reg)
			regulator_set_voltage_tol(cpu_reg, volt_old, tol);
		return ret;
	}

	/* scaling down?  scale voltage after frequency */
	if (cpu_reg && freqs.new < freqs.old) {
		ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
		if (ret) {
			pr_err("failed to scale voltage down: %d\n", ret);
			clk_set_rate(cpu_clk, freqs.old * 1000);
			freqs.new = freqs.old;
			return ret;
		}
	}

	for_each_online_cpu(cpu) {
		freqs.cpu = cpu;
		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	}

	return 0;
}

static int cpu0_cpufreq_init(struct cpufreq_policy *policy)
{
	int ret;

	if (policy->cpu != 0)
		return -EINVAL;

	ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
	if (ret) {
		pr_err("invalid frequency table: %d\n", ret);
		return ret;
	}

	policy->cpuinfo.transition_latency = transition_latency;
	policy->cur = clk_get_rate(cpu_clk) / 1000;

	/*
	 * The driver only supports the SMP configuartion where all processors
	 * share the clock and voltage and clock.  Use cpufreq affected_cpus
	 * interface to have all CPUs scaled together.
	 */
	policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
	cpumask_setall(policy->cpus);

	cpufreq_frequency_table_get_attr(freq_table, policy->cpu);

	return 0;
}

static int cpu0_cpufreq_exit(struct cpufreq_policy *policy)
{
	cpufreq_frequency_table_put_attr(policy->cpu);

	return 0;
}

static struct freq_attr *cpu0_cpufreq_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver cpu0_cpufreq_driver = {
	.flags = CPUFREQ_STICKY,
	.verify = cpu0_verify_speed,
	.target = cpu0_set_target,
	.get = cpu0_get_speed,
	.init = cpu0_cpufreq_init,
	.exit = cpu0_cpufreq_exit,
	.name = "generic_cpu0",
	.attr = cpu0_cpufreq_attr,
};

static int __devinit cpu0_cpufreq_driver_init(void)
{
	struct device_node *np;
	int ret;

	np = of_find_node_by_path("/cpus/cpu@0");
	if (!np) {
		pr_err("failed to find cpu0 node\n");
		return -ENOENT;
	}

	cpu_dev = get_cpu_device(0);
	if (!cpu_dev) {
		pr_err("failed to get cpu0 device\n");
		ret = -ENODEV;
		goto out_put_node;
	}

	cpu_dev->of_node = np;

	cpu_clk = clk_get(cpu_dev, NULL);
	if (IS_ERR(cpu_clk)) {
		ret = PTR_ERR(cpu_clk);
		pr_err("failed to get cpu0 clock: %d\n", ret);
		goto out_put_node;
	}

	cpu_reg = regulator_get(cpu_dev, "cpu0");
	if (IS_ERR(cpu_reg)) {
		pr_warn("failed to get cpu0 regulator\n");
		cpu_reg = NULL;
	}

	ret = of_init_opp_table(cpu_dev);
	if (ret) {
		pr_err("failed to init OPP table: %d\n", ret);
		goto out_put_node;
	}

	ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
	if (ret) {
		pr_err("failed to init cpufreq table: %d\n", ret);
		goto out_put_node;
	}

	of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);

	if (of_property_read_u32(np, "clock-latency", &transition_latency))
		transition_latency = CPUFREQ_ETERNAL;

	if (cpu_reg) {
		struct opp *opp;
		unsigned long min_uV, max_uV;
		int i;

		/*
		 * OPP is maintained in order of increasing frequency, and
		 * freq_table initialised from OPP is therefore sorted in the
		 * same order.
		 */
		for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
			;
		opp = opp_find_freq_exact(cpu_dev,
				freq_table[0].frequency * 1000, true);
		min_uV = opp_get_voltage(opp);
		opp = opp_find_freq_exact(cpu_dev,
				freq_table[i-1].frequency * 1000, true);
		max_uV = opp_get_voltage(opp);
		ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
		if (ret > 0)
			transition_latency += ret * 1000;
	}

	ret = cpufreq_register_driver(&cpu0_cpufreq_driver);
	if (ret) {
		pr_err("failed register driver: %d\n", ret);
		goto out_free_table;
	}

	of_node_put(np);
	return 0;

out_free_table:
	opp_free_cpufreq_table(cpu_dev, &freq_table);
out_put_node:
	of_node_put(np);
	return ret;
}
late_initcall(cpu0_cpufreq_driver_init);

MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
MODULE_DESCRIPTION("Generic CPU0 cpufreq driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
95ceafd4 SG	1	/*
	2	* Copyright (C) 2012 Freescale Semiconductor, Inc.
	3	*
	4	* The OPP code in function cpu0_set_target() is reused from
	5	* drivers/cpufreq/omap-cpufreq.c
	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/cpufreq.h>
	17	#include <linux/err.h>
	18	#include <linux/module.h>
	19	#include <linux/of.h>
	20	#include <linux/opp.h>
	21	#include <linux/regulator/consumer.h>
	22	#include <linux/slab.h>
	23
	24	static unsigned int transition_latency;
	25	static unsigned int voltage_tolerance; /* in percentage */
	26
	27	static struct device *cpu_dev;
	28	static struct clk *cpu_clk;
	29	static struct regulator *cpu_reg;
	30	static struct cpufreq_frequency_table *freq_table;
	31
	32	static int cpu0_verify_speed(struct cpufreq_policy *policy)
	33	{
	34	return cpufreq_frequency_table_verify(policy, freq_table);
	35	}
	36
	37	static unsigned int cpu0_get_speed(unsigned int cpu)
	38	{
	39	return clk_get_rate(cpu_clk) / 1000;
	40	}
	41
	42	static int cpu0_set_target(struct cpufreq_policy *policy,
	43	unsigned int target_freq, unsigned int relation)
	44	{
	45	struct cpufreq_freqs freqs;
	46	struct opp *opp;
	47	unsigned long freq_Hz, volt = 0, volt_old = 0, tol = 0;
	48	unsigned int index, cpu;
	49	int ret;
	50
	51	ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
	52	relation, &index);
	53	if (ret) {
	54	pr_err("failed to match target freqency %d: %d\n",
	55	target_freq, ret);
	56	return ret;
	57	}
	58
	59	freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
	60	if (freq_Hz < 0)
	61	freq_Hz = freq_table[index].frequency * 1000;
	62	freqs.new = freq_Hz / 1000;
	63	freqs.old = clk_get_rate(cpu_clk) / 1000;
	64
65	if (freqs.old == freqs.new)
66	return 0;
67
68	for_each_online_cpu(cpu) {
69	freqs.cpu = cpu;
70	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
71	}
72
73	if (cpu_reg) {
74	opp = opp_find_freq_ceil(cpu_dev, &freq_Hz);
75	if (IS_ERR(opp)) {
76	pr_err("failed to find OPP for %ld\n", freq_Hz);
77	return PTR_ERR(opp);
78	}
79	volt = opp_get_voltage(opp);
80	tol = volt * voltage_tolerance / 100;
81	volt_old = regulator_get_voltage(cpu_reg);
82	}
83
84	pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
85	freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
86	freqs.new / 1000, volt ? volt / 1000 : -1);
87
88	/* scaling up? scale voltage before frequency */
89	if (cpu_reg && freqs.new > freqs.old) {
90	ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
91	if (ret) {
92	pr_err("failed to scale voltage up: %d\n", ret);
93	freqs.new = freqs.old;
94	return ret;
95	}
96	}
97
98	ret = clk_set_rate(cpu_clk, freqs.new * 1000);
99	if (ret) {
100	pr_err("failed to set clock rate: %d\n", ret);
101	if (cpu_reg)
102	regulator_set_voltage_tol(cpu_reg, volt_old, tol);
103	return ret;
104	}
105
106	/* scaling down? scale voltage after frequency */
107	if (cpu_reg && freqs.new < freqs.old) {
108	ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
109	if (ret) {
110	pr_err("failed to scale voltage down: %d\n", ret);
111	clk_set_rate(cpu_clk, freqs.old * 1000);
112	freqs.new = freqs.old;
113	return ret;
114	}
115	}
116
117	for_each_online_cpu(cpu) {
118	freqs.cpu = cpu;
119	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
120	}
121
122	return 0;
123	}
124
125	static int cpu0_cpufreq_init(struct cpufreq_policy *policy)
126	{
127	int ret;
128
129	if (policy->cpu != 0)
130	return -EINVAL;
131
132	ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
133	if (ret) {
134	pr_err("invalid frequency table: %d\n", ret);
135	return ret;
136	}
137
138	policy->cpuinfo.transition_latency = transition_latency;
139	policy->cur = clk_get_rate(cpu_clk) / 1000;
140
141	/*
142	* The driver only supports the SMP configuartion where all processors
143	* share the clock and voltage and clock. Use cpufreq affected_cpus
144	* interface to have all CPUs scaled together.
145	*/
146	policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
147	cpumask_setall(policy->cpus);
148
149	cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
150
151	return 0;
152	}
153
154	static int cpu0_cpufreq_exit(struct cpufreq_policy *policy)
155	{
156	cpufreq_frequency_table_put_attr(policy->cpu);
157
158	return 0;
159	}
160
161	static struct freq_attr *cpu0_cpufreq_attr[] = {
162	&cpufreq_freq_attr_scaling_available_freqs,
163	NULL,
164	};
165
166	static struct cpufreq_driver cpu0_cpufreq_driver = {
167	.flags = CPUFREQ_STICKY,
168	.verify = cpu0_verify_speed,
169	.target = cpu0_set_target,
170	.get = cpu0_get_speed,
171	.init = cpu0_cpufreq_init,
172	.exit = cpu0_cpufreq_exit,
173	.name = "generic_cpu0",
174	.attr = cpu0_cpufreq_attr,
175	};
176
177	static int __devinit cpu0_cpufreq_driver_init(void)
178	{
179	struct device_node *np;
180	int ret;
181
182	np = of_find_node_by_path("/cpus/cpu@0");
183	if (!np) {
184	pr_err("failed to find cpu0 node\n");
185	return -ENOENT;
186	}
187
188	cpu_dev = get_cpu_device(0);
189	if (!cpu_dev) {
190	pr_err("failed to get cpu0 device\n");
191	ret = -ENODEV;
192	goto out_put_node;
193	}
194
195	cpu_dev->of_node = np;
196
197	cpu_clk = clk_get(cpu_dev, NULL);
198	if (IS_ERR(cpu_clk)) {
199	ret = PTR_ERR(cpu_clk);
200	pr_err("failed to get cpu0 clock: %d\n", ret);
201	goto out_put_node;
202	}
203
204	cpu_reg = regulator_get(cpu_dev, "cpu0");
205	if (IS_ERR(cpu_reg)) {
206	pr_warn("failed to get cpu0 regulator\n");
207	cpu_reg = NULL;
208	}
209
210	ret = of_init_opp_table(cpu_dev);
211	if (ret) {
212	pr_err("failed to init OPP table: %d\n", ret);
213	goto out_put_node;
214	}
215
216	ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
217	if (ret) {
218	pr_err("failed to init cpufreq table: %d\n", ret);
219	goto out_put_node;
220	}
221
222	of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);
223
224	if (of_property_read_u32(np, "clock-latency", &transition_latency))
225	transition_latency = CPUFREQ_ETERNAL;
226
227	if (cpu_reg) {
228	struct opp *opp;
229	unsigned long min_uV, max_uV;
230	int i;
231
232	/*
233	* OPP is maintained in order of increasing frequency, and
234	* freq_table initialised from OPP is therefore sorted in the
235	* same order.
236	*/
237	for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
238	;
239	opp = opp_find_freq_exact(cpu_dev,
240	freq_table[0].frequency * 1000, true);
241	min_uV = opp_get_voltage(opp);
242	opp = opp_find_freq_exact(cpu_dev,
243	freq_table[i-1].frequency * 1000, true);
244	max_uV = opp_get_voltage(opp);
245	ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
246	if (ret > 0)
247	transition_latency += ret * 1000;
248	}
249
250	ret = cpufreq_register_driver(&cpu0_cpufreq_driver);
251	if (ret) {
252	pr_err("failed register driver: %d\n", ret);
253	goto out_free_table;
254	}
255
256	of_node_put(np);
257	return 0;
258
259	out_free_table:
260	opp_free_cpufreq_table(cpu_dev, &freq_table);
261	out_put_node:
262	of_node_put(np);
263	return ret;
264	}
265	late_initcall(cpu0_cpufreq_driver_init);
266
267	MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
268	MODULE_DESCRIPTION("Generic CPU0 cpufreq driver");
269	MODULE_LICENSE("GPL");