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

/*
 * drivers/cpufreq/spear-cpufreq.c
 *
 * CPU Frequency Scaling for SPEAr platform
 *
 * Copyright (C) 2012 ST Microelectronics
 * Deepak Sikri <deepak.sikri@st.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/types.h>

/* SPEAr CPUFreq driver data structure */
static struct {
	struct clk *clk;
	unsigned int transition_latency;
	struct cpufreq_frequency_table *freq_tbl;
	u32 cnt;
} spear_cpufreq;

static int spear_cpufreq_verify(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, spear_cpufreq.freq_tbl);
}

static unsigned int spear_cpufreq_get(unsigned int cpu)
{
	return clk_get_rate(spear_cpufreq.clk) / 1000;
}

static struct clk *spear1340_cpu_get_possible_parent(unsigned long newfreq)
{
	struct clk *sys_pclk;
	int pclk;
	/*
	 * In SPEAr1340, cpu clk's parent sys clk can take input from
	 * following sources
	 */
	const char *sys_clk_src[] = {
		"sys_syn_clk",
		"pll1_clk",
		"pll2_clk",
		"pll3_clk",
	};

	/*
	 * As sys clk can have multiple source with their own range
	 * limitation so we choose possible sources accordingly
	 */
	if (newfreq <= 300000000)
		pclk = 0; /* src is sys_syn_clk */
	else if (newfreq > 300000000 && newfreq <= 500000000)
		pclk = 3; /* src is pll3_clk */
	else if (newfreq == 600000000)
		pclk = 1; /* src is pll1_clk */
	else
		return ERR_PTR(-EINVAL);

	/* Get parent to sys clock */
	sys_pclk = clk_get(NULL, sys_clk_src[pclk]);
	if (IS_ERR(sys_pclk))
		pr_err("Failed to get %s clock\n", sys_clk_src[pclk]);

	return sys_pclk;
}

/*
 * In SPEAr1340, we cannot use newfreq directly because we need to actually
 * access a source clock (clk) which might not be ancestor of cpu at present.
 * Hence in SPEAr1340 we would operate on source clock directly before switching
 * cpu clock to it.
 */
static int spear1340_set_cpu_rate(struct clk *sys_pclk, unsigned long newfreq)
{
	struct clk *sys_clk;
	int ret = 0;

	sys_clk = clk_get_parent(spear_cpufreq.clk);
	if (IS_ERR(sys_clk)) {
		pr_err("failed to get cpu's parent (sys) clock\n");
		return PTR_ERR(sys_clk);
	}

	/* Set the rate of the source clock before changing the parent */
	ret = clk_set_rate(sys_pclk, newfreq);
	if (ret) {
		pr_err("Failed to set sys clk rate to %lu\n", newfreq);
		return ret;
	}

	ret = clk_set_parent(sys_clk, sys_pclk);
	if (ret) {
		pr_err("Failed to set sys clk parent\n");
		return ret;
	}

	return 0;
}

static int spear_cpufreq_target(struct cpufreq_policy *policy,
		unsigned int target_freq, unsigned int relation)
{
	struct cpufreq_freqs freqs;
	unsigned long newfreq;
	struct clk *srcclk;
	int index, ret, mult = 1;

	if (cpufreq_frequency_table_target(policy, spear_cpufreq.freq_tbl,
				target_freq, relation, &index))
		return -EINVAL;

	freqs.cpu = policy->cpu;
	freqs.old = spear_cpufreq_get(0);

	newfreq = spear_cpufreq.freq_tbl[index].frequency * 1000;
	if (of_machine_is_compatible("st,spear1340")) {
		/*
		 * SPEAr1340 is special in the sense that due to the possibility
		 * of multiple clock sources for cpu clk's parent we can have
		 * different clock source for different frequency of cpu clk.
		 * Hence we need to choose one from amongst these possible clock
		 * sources.
		 */
		srcclk = spear1340_cpu_get_possible_parent(newfreq);
		if (IS_ERR(srcclk)) {
			pr_err("Failed to get src clk\n");
			return PTR_ERR(srcclk);
		}

		/* SPEAr1340: src clk is always 2 * intended cpu clk */
		mult = 2;
	} else {
		/*
		 * src clock to be altered is ancestor of cpu clock. Hence we
		 * can directly work on cpu clk
		 */
		srcclk = spear_cpufreq.clk;
	}

	newfreq = clk_round_rate(srcclk, newfreq * mult);
	if (newfreq < 0) {
		pr_err("clk_round_rate failed for cpu src clock\n");
		return newfreq;
	}

	freqs.new = newfreq / 1000;
	freqs.new /= mult;

	for_each_cpu(freqs.cpu, policy->cpus)
		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

	if (mult == 2)
		ret = spear1340_set_cpu_rate(srcclk, newfreq);
	else
		ret = clk_set_rate(spear_cpufreq.clk, newfreq);

	/* Get current rate after clk_set_rate, in case of failure */
	if (ret) {
		pr_err("CPU Freq: cpu clk_set_rate failed: %d\n", ret);
		freqs.new = clk_get_rate(spear_cpufreq.clk) / 1000;
	}

	for_each_cpu(freqs.cpu, policy->cpus)
		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	return ret;
}

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

	ret = cpufreq_frequency_table_cpuinfo(policy, spear_cpufreq.freq_tbl);
	if (ret) {
		pr_err("cpufreq_frequency_table_cpuinfo() failed");
		return ret;
	}

	cpufreq_frequency_table_get_attr(spear_cpufreq.freq_tbl, policy->cpu);
	policy->cpuinfo.transition_latency = spear_cpufreq.transition_latency;
	policy->cur = spear_cpufreq_get(0);

	cpumask_setall(policy->cpus);

	return 0;
}

static int spear_cpufreq_exit(struct cpufreq_policy *policy)
{
	cpufreq_frequency_table_put_attr(policy->cpu);
	return 0;
}

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

static struct cpufreq_driver spear_cpufreq_driver = {
	.name		= "cpufreq-spear",
	.flags		= CPUFREQ_STICKY,
	.verify		= spear_cpufreq_verify,
	.target		= spear_cpufreq_target,
	.get		= spear_cpufreq_get,
	.init		= spear_cpufreq_init,
	.exit		= spear_cpufreq_exit,
	.attr		= spear_cpufreq_attr,
};

static int spear_cpufreq_driver_init(void)
{
	struct device_node *np;
	const struct property *prop;
	struct cpufreq_frequency_table *freq_tbl;
	const __be32 *val;
	int cnt, i, ret;

	np = of_find_node_by_path("/cpus/cpu@0");
	if (!np) {
		pr_err("No cpu node found");
		return -ENODEV;
	}

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

	prop = of_find_property(np, "cpufreq_tbl", NULL);
	if (!prop || !prop->value) {
		pr_err("Invalid cpufreq_tbl");
		ret = -ENODEV;
		goto out_put_node;
	}

	cnt = prop->length / sizeof(u32);
	val = prop->value;

	freq_tbl = kmalloc(sizeof(*freq_tbl) * (cnt + 1), GFP_KERNEL);
	if (!freq_tbl) {
		ret = -ENOMEM;
		goto out_put_node;
	}

	for (i = 0; i < cnt; i++) {
		freq_tbl[i].index = i;
		freq_tbl[i].frequency = be32_to_cpup(val++);
	}

	freq_tbl[i].index = i;
	freq_tbl[i].frequency = CPUFREQ_TABLE_END;

	spear_cpufreq.freq_tbl = freq_tbl;

	of_node_put(np);

	spear_cpufreq.clk = clk_get(NULL, "cpu_clk");
	if (IS_ERR(spear_cpufreq.clk)) {
		pr_err("Unable to get CPU clock\n");
		ret = PTR_ERR(spear_cpufreq.clk);
		goto out_put_mem;
	}

	ret = cpufreq_register_driver(&spear_cpufreq_driver);
	if (!ret)
		return 0;

	pr_err("failed register driver: %d\n", ret);
	clk_put(spear_cpufreq.clk);

out_put_mem:
	kfree(freq_tbl);
	return ret;

out_put_node:
	of_node_put(np);
	return ret;
}
late_initcall(spear_cpufreq_driver_init);

MODULE_AUTHOR("Deepak Sikri <deepak.sikri@st.com>");
MODULE_DESCRIPTION("SPEAr CPUFreq driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
42099322 DS	1	/*
	2	* drivers/cpufreq/spear-cpufreq.c
	3	*
	4	* CPU Frequency Scaling for SPEAr platform
	5	*
	6	* Copyright (C) 2012 ST Microelectronics
	7	* Deepak Sikri <deepak.sikri@st.com>
	8	*
	9	* This file is licensed under the terms of the GNU General Public
	10	* License version 2. This program is licensed "as is" without any
	11	* warranty of any kind, whether express or implied.
	12	*/
	13
	14	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	15
	16	#include <linux/clk.h>
	17	#include <linux/cpufreq.h>
	18	#include <linux/err.h>
	19	#include <linux/init.h>
	20	#include <linux/module.h>
	21	#include <linux/of.h>
	22	#include <linux/slab.h>
	23	#include <linux/types.h>
	24
	25	/* SPEAr CPUFreq driver data structure */
	26	static struct {
	27	struct clk *clk;
	28	unsigned int transition_latency;
	29	struct cpufreq_frequency_table *freq_tbl;
	30	u32 cnt;
	31	} spear_cpufreq;
	32
f8517804	33	static int spear_cpufreq_verify(struct cpufreq_policy *policy)
42099322 DS	34	{
	35	return cpufreq_frequency_table_verify(policy, spear_cpufreq.freq_tbl);
	36	}
	37
	38	static unsigned int spear_cpufreq_get(unsigned int cpu)
	39	{
	40	return clk_get_rate(spear_cpufreq.clk) / 1000;
	41	}
	42
	43	static struct clk *spear1340_cpu_get_possible_parent(unsigned long newfreq)
	44	{
	45	struct clk *sys_pclk;
	46	int pclk;
	47	/*
	48	* In SPEAr1340, cpu clk's parent sys clk can take input from
	49	* following sources
	50	*/
	51	const char *sys_clk_src[] = {
	52	"sys_syn_clk",
	53	"pll1_clk",
	54	"pll2_clk",
	55	"pll3_clk",
	56	};
	57
	58	/*
	59	* As sys clk can have multiple source with their own range
	60	* limitation so we choose possible sources accordingly
	61	*/
	62	if (newfreq <= 300000000)
	63	pclk = 0; /* src is sys_syn_clk */
	64	else if (newfreq > 300000000 && newfreq <= 500000000)
	65	pclk = 3; /* src is pll3_clk */
	66	else if (newfreq == 600000000)
	67	pclk = 1; /* src is pll1_clk */
	68	else
	69	return ERR_PTR(-EINVAL);
	70
	71	/* Get parent to sys clock */
	72	sys_pclk = clk_get(NULL, sys_clk_src[pclk]);
	73	if (IS_ERR(sys_pclk))
	74	pr_err("Failed to get %s clock\n", sys_clk_src[pclk]);
	75
	76	return sys_pclk;
	77	}
	78
	79	/*
	80	* In SPEAr1340, we cannot use newfreq directly because we need to actually
	81	* access a source clock (clk) which might not be ancestor of cpu at present.
	82	* Hence in SPEAr1340 we would operate on source clock directly before switching
	83	* cpu clock to it.
	84	*/
	85	static int spear1340_set_cpu_rate(struct clk *sys_pclk, unsigned long newfreq)
	86	{
	87	struct clk *sys_clk;
	88	int ret = 0;
	89
	90	sys_clk = clk_get_parent(spear_cpufreq.clk);
	91	if (IS_ERR(sys_clk)) {
	92	pr_err("failed to get cpu's parent (sys) clock\n");
	93	return PTR_ERR(sys_clk);
	94	}
	95
	96	/* Set the rate of the source clock before changing the parent */
	97	ret = clk_set_rate(sys_pclk, newfreq);
98	if (ret) {
99	pr_err("Failed to set sys clk rate to %lu\n", newfreq);
100	return ret;
101	}
102
103	ret = clk_set_parent(sys_clk, sys_pclk);
104	if (ret) {
105	pr_err("Failed to set sys clk parent\n");
106	return ret;
107	}
108
109	return 0;
110	}
111
112	static int spear_cpufreq_target(struct cpufreq_policy *policy,
113	unsigned int target_freq, unsigned int relation)
114	{
115	struct cpufreq_freqs freqs;
116	unsigned long newfreq;
117	struct clk *srcclk;
118	int index, ret, mult = 1;
119
120	if (cpufreq_frequency_table_target(policy, spear_cpufreq.freq_tbl,
121	target_freq, relation, &index))
122	return -EINVAL;
123
124	freqs.cpu = policy->cpu;
125	freqs.old = spear_cpufreq_get(0);
126
127	newfreq = spear_cpufreq.freq_tbl[index].frequency * 1000;
128	if (of_machine_is_compatible("st,spear1340")) {
129	/*
130	* SPEAr1340 is special in the sense that due to the possibility
131	* of multiple clock sources for cpu clk's parent we can have
132	* different clock source for different frequency of cpu clk.
133	* Hence we need to choose one from amongst these possible clock
134	* sources.
135	*/
136	srcclk = spear1340_cpu_get_possible_parent(newfreq);
137	if (IS_ERR(srcclk)) {
138	pr_err("Failed to get src clk\n");
139	return PTR_ERR(srcclk);
140	}
141
142	/* SPEAr1340: src clk is always 2 * intended cpu clk */
143	mult = 2;
144	} else {
145	/*
146	* src clock to be altered is ancestor of cpu clock. Hence we
147	* can directly work on cpu clk
148	*/
149	srcclk = spear_cpufreq.clk;
150	}
151
152	newfreq = clk_round_rate(srcclk, newfreq * mult);
153	if (newfreq < 0) {
154	pr_err("clk_round_rate failed for cpu src clock\n");
155	return newfreq;
156	}
157
158	freqs.new = newfreq / 1000;
159	freqs.new /= mult;
6f35a65f VK	160
	161	for_each_cpu(freqs.cpu, policy->cpus)
	162	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
42099322 DS	163
	164	if (mult == 2)
	165	ret = spear1340_set_cpu_rate(srcclk, newfreq);
	166	else
	167	ret = clk_set_rate(spear_cpufreq.clk, newfreq);
	168
	169	/* Get current rate after clk_set_rate, in case of failure */
	170	if (ret) {
	171	pr_err("CPU Freq: cpu clk_set_rate failed: %d\n", ret);
	172	freqs.new = clk_get_rate(spear_cpufreq.clk) / 1000;
	173	}
	174
6f35a65f VK	175	for_each_cpu(freqs.cpu, policy->cpus)
6f35a65f VK	176	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
42099322 DS	177	return ret;
	178	}
	179
	180	static int spear_cpufreq_init(struct cpufreq_policy *policy)
	181	{
	182	int ret;
	183
	184	ret = cpufreq_frequency_table_cpuinfo(policy, spear_cpufreq.freq_tbl);
	185	if (ret) {
	186	pr_err("cpufreq_frequency_table_cpuinfo() failed");
	187	return ret;
	188	}
	189
	190	cpufreq_frequency_table_get_attr(spear_cpufreq.freq_tbl, policy->cpu);
	191	policy->cpuinfo.transition_latency = spear_cpufreq.transition_latency;
	192	policy->cur = spear_cpufreq_get(0);
	193
4c738d00	194	cpumask_setall(policy->cpus);
42099322 DS	195
	196	return 0;
	197	}
	198
	199	static int spear_cpufreq_exit(struct cpufreq_policy *policy)
	200	{
	201	cpufreq_frequency_table_put_attr(policy->cpu);
	202	return 0;
	203	}
	204
	205	static struct freq_attr *spear_cpufreq_attr[] = {
	206	&cpufreq_freq_attr_scaling_available_freqs,
	207	NULL,
	208	};
	209
	210	static struct cpufreq_driver spear_cpufreq_driver = {
	211	.name = "cpufreq-spear",
	212	.flags = CPUFREQ_STICKY,
	213	.verify = spear_cpufreq_verify,
	214	.target = spear_cpufreq_target,
	215	.get = spear_cpufreq_get,
	216	.init = spear_cpufreq_init,
	217	.exit = spear_cpufreq_exit,
	218	.attr = spear_cpufreq_attr,
	219	};
	220
	221	static int spear_cpufreq_driver_init(void)
	222	{
	223	struct device_node *np;
	224	const struct property *prop;
	225	struct cpufreq_frequency_table *freq_tbl;
	226	const __be32 *val;
	227	int cnt, i, ret;
	228
	229	np = of_find_node_by_path("/cpus/cpu@0");
	230	if (!np) {
	231	pr_err("No cpu node found");
	232	return -ENODEV;
	233	}
	234
	235	if (of_property_read_u32(np, "clock-latency",
	236	&spear_cpufreq.transition_latency))
	237	spear_cpufreq.transition_latency = CPUFREQ_ETERNAL;
	238
	239	prop = of_find_property(np, "cpufreq_tbl", NULL);
	240	if (!prop \|\| !prop->value) {
	241	pr_err("Invalid cpufreq_tbl");
	242	ret = -ENODEV;
	243	goto out_put_node;
	244	}
	245
	246	cnt = prop->length / sizeof(u32);
	247	val = prop->value;
	248
	249	freq_tbl = kmalloc(sizeof(freq_tbl) (cnt + 1), GFP_KERNEL);
	250	if (!freq_tbl) {
	251	ret = -ENOMEM;
	252	goto out_put_node;
	253	}
	254
	255	for (i = 0; i < cnt; i++) {
	256	freq_tbl[i].index = i;
	257	freq_tbl[i].frequency = be32_to_cpup(val++);
	258	}
259
260	freq_tbl[i].index = i;
261	freq_tbl[i].frequency = CPUFREQ_TABLE_END;
262
263	spear_cpufreq.freq_tbl = freq_tbl;
264
265	of_node_put(np);
266
267	spear_cpufreq.clk = clk_get(NULL, "cpu_clk");
268	if (IS_ERR(spear_cpufreq.clk)) {
269	pr_err("Unable to get CPU clock\n");
270	ret = PTR_ERR(spear_cpufreq.clk);
271	goto out_put_mem;
272	}
273
274	ret = cpufreq_register_driver(&spear_cpufreq_driver);
275	if (!ret)
276	return 0;
277
278	pr_err("failed register driver: %d\n", ret);
279	clk_put(spear_cpufreq.clk);
280
281	out_put_mem:
282	kfree(freq_tbl);
283	return ret;
284
285	out_put_node:
286	of_node_put(np);
287	return ret;
288	}
289	late_initcall(spear_cpufreq_driver_init);
290
291	MODULE_AUTHOR("Deepak Sikri <deepak.sikri@st.com>");
292	MODULE_DESCRIPTION("SPEAr CPUFreq driver");
293	MODULE_LICENSE("GPL");