[deliverable/linux.git] / drivers / cpufreq / kirkwood-cpufreq.c

/*
 *	kirkwood_freq.c: cpufreq driver for the Marvell kirkwood
 *
 *	Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/cpufreq.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <asm/proc-fns.h>

#define CPU_SW_INT_BLK BIT(28)

static struct priv
{
	struct clk *cpu_clk;
	struct clk *ddr_clk;
	struct clk *powersave_clk;
	struct device *dev;
	void __iomem *base;
} priv;

#define STATE_CPU_FREQ 0x01
#define STATE_DDR_FREQ 0x02

/*
 * Kirkwood can swap the clock to the CPU between two clocks:
 *
 * - cpu clk
 * - ddr clk
 *
 * The frequencies are set at runtime before registering this *
 * table.
 */
static struct cpufreq_frequency_table kirkwood_freq_table[] = {
	{STATE_CPU_FREQ,	0}, /* CPU uses cpuclk */
	{STATE_DDR_FREQ,	0}, /* CPU uses ddrclk */
	{0,			CPUFREQ_TABLE_END},
};

static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu)
{
	if (__clk_is_enabled(priv.powersave_clk))
		return kirkwood_freq_table[1].frequency;
	return kirkwood_freq_table[0].frequency;
}

static void kirkwood_cpufreq_set_cpu_state(unsigned int index)
{
	struct cpufreq_freqs freqs;
	unsigned int state = kirkwood_freq_table[index].index;
	unsigned long reg;

	freqs.old = kirkwood_cpufreq_get_cpu_frequency(0);
	freqs.new = kirkwood_freq_table[index].frequency;
	freqs.cpu = 0; /* Kirkwood is UP */

	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

	dev_dbg(priv.dev, "Attempting to set frequency to %i KHz\n",
		kirkwood_freq_table[index].frequency);
	dev_dbg(priv.dev, "old frequency was %i KHz\n",
		kirkwood_cpufreq_get_cpu_frequency(0));

	if (freqs.old != freqs.new) {
		local_irq_disable();

		/* Disable interrupts to the CPU */
		reg = readl_relaxed(priv.base);
		reg |= CPU_SW_INT_BLK;
		writel_relaxed(reg, priv.base);

		switch (state) {
		case STATE_CPU_FREQ:
			clk_disable(priv.powersave_clk);
			break;
		case STATE_DDR_FREQ:
			clk_enable(priv.powersave_clk);
			break;
		}

		/* Wait-for-Interrupt, while the hardware changes frequency */
		cpu_do_idle();

		/* Enable interrupts to the CPU */
		reg = readl_relaxed(priv.base);
		reg &= ~CPU_SW_INT_BLK;
		writel_relaxed(reg, priv.base);

		local_irq_enable();
	}
	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
};

static int kirkwood_cpufreq_verify(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, kirkwood_freq_table);
}

static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,
			    unsigned int target_freq,
			    unsigned int relation)
{
	unsigned int index = 0;

	if (cpufreq_frequency_table_target(policy, kirkwood_freq_table,
				target_freq, relation, &index))
		return -EINVAL;

	kirkwood_cpufreq_set_cpu_state(index);

	return 0;
}

/* Module init and exit code */
static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
	int result;

	/* cpuinfo and default policy values */
	policy->cpuinfo.transition_latency = 5000; /* 5uS */
	policy->cur = kirkwood_cpufreq_get_cpu_frequency(0);

	result = cpufreq_frequency_table_cpuinfo(policy, kirkwood_freq_table);
	if (result)
		return result;

	cpufreq_frequency_table_get_attr(kirkwood_freq_table, policy->cpu);

	return 0;
}

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

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

static struct cpufreq_driver kirkwood_cpufreq_driver = {
	.get	= kirkwood_cpufreq_get_cpu_frequency,
	.verify	= kirkwood_cpufreq_verify,
	.target	= kirkwood_cpufreq_target,
	.init	= kirkwood_cpufreq_cpu_init,
	.exit	= kirkwood_cpufreq_cpu_exit,
	.name	= "kirkwood-cpufreq",
	.owner	= THIS_MODULE,
	.attr	= kirkwood_cpufreq_attr,
};

static int kirkwood_cpufreq_probe(struct platform_device *pdev)
{
	struct device_node *np;
	struct resource *res;
	int err;

	priv.dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "Cannot get memory resource\n");
		return -ENODEV;
	}
	priv.base = devm_request_and_ioremap(&pdev->dev, res);
	if (!priv.base) {
		dev_err(&pdev->dev, "Cannot ioremap\n");
		return -EADDRNOTAVAIL;
	}

	np = of_find_node_by_path("/cpus/cpu@0");
	if (!np)
		return -ENODEV;

	priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk");
	if (IS_ERR(priv.cpu_clk)) {
		dev_err(priv.dev, "Unable to get cpuclk");
		return PTR_ERR(priv.cpu_clk);
	}

	clk_prepare_enable(priv.cpu_clk);
	kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000;

	priv.ddr_clk = of_clk_get_by_name(np, "ddrclk");
	if (IS_ERR(priv.ddr_clk)) {
		dev_err(priv.dev, "Unable to get ddrclk");
		err = PTR_ERR(priv.ddr_clk);
		goto out_cpu;
	}

	clk_prepare_enable(priv.ddr_clk);
	kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000;

	priv.powersave_clk = of_clk_get_by_name(np, "powersave");
	if (IS_ERR(priv.powersave_clk)) {
		dev_err(priv.dev, "Unable to get powersave");
		err = PTR_ERR(priv.powersave_clk);
		goto out_ddr;
	}
	clk_prepare(priv.powersave_clk);

	of_node_put(np);
	np = NULL;

	err = cpufreq_register_driver(&kirkwood_cpufreq_driver);
	if (!err)
		return 0;

	dev_err(priv.dev, "Failed to register cpufreq driver");

	clk_disable_unprepare(priv.powersave_clk);
out_ddr:
	clk_disable_unprepare(priv.ddr_clk);
out_cpu:
	clk_disable_unprepare(priv.cpu_clk);
	of_node_put(np);

	return err;
}

static int kirkwood_cpufreq_remove(struct platform_device *pdev)
{
	cpufreq_unregister_driver(&kirkwood_cpufreq_driver);

	clk_disable_unprepare(priv.powersave_clk);
	clk_disable_unprepare(priv.ddr_clk);
	clk_disable_unprepare(priv.cpu_clk);

	return 0;
}

static struct platform_driver kirkwood_cpufreq_platform_driver = {
	.probe = kirkwood_cpufreq_probe,
	.remove = kirkwood_cpufreq_remove,
	.driver = {
		.name = "kirkwood-cpufreq",
		.owner = THIS_MODULE,
	},
};

module_platform_driver(kirkwood_cpufreq_platform_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");
MODULE_ALIAS("platform:kirkwood-cpufreq");
Commit	Line	Data
2a4bd9f0 AL	1	/*
	2	* kirkwood_freq.c: cpufreq driver for the Marvell kirkwood
	3	*
	4	* Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/clk.h>
	15	#include <linux/clk-provider.h>
	16	#include <linux/cpufreq.h>
	17	#include <linux/of.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/io.h>
	20	#include <asm/proc-fns.h>
	21
	22	#define CPU_SW_INT_BLK BIT(28)
	23
	24	static struct priv
	25	{
	26	struct clk *cpu_clk;
	27	struct clk *ddr_clk;
	28	struct clk *powersave_clk;
	29	struct device *dev;
	30	void __iomem *base;
	31	} priv;
	32
	33	#define STATE_CPU_FREQ 0x01
	34	#define STATE_DDR_FREQ 0x02
	35
	36	/*
	37	* Kirkwood can swap the clock to the CPU between two clocks:
	38	*
	39	* - cpu clk
	40	* - ddr clk
	41	*
	42	* The frequencies are set at runtime before registering this *
	43	* table.
	44	*/
	45	static struct cpufreq_frequency_table kirkwood_freq_table[] = {
	46	{STATE_CPU_FREQ, 0}, /* CPU uses cpuclk */
	47	{STATE_DDR_FREQ, 0}, /* CPU uses ddrclk */
	48	{0, CPUFREQ_TABLE_END},
	49	};
	50
	51	static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu)
	52	{
	53	if (__clk_is_enabled(priv.powersave_clk))
	54	return kirkwood_freq_table[1].frequency;
	55	return kirkwood_freq_table[0].frequency;
	56	}
	57
	58	static void kirkwood_cpufreq_set_cpu_state(unsigned int index)
	59	{
	60	struct cpufreq_freqs freqs;
	61	unsigned int state = kirkwood_freq_table[index].index;
	62	unsigned long reg;
	63
	64	freqs.old = kirkwood_cpufreq_get_cpu_frequency(0);
65	freqs.new = kirkwood_freq_table[index].frequency;
66	freqs.cpu = 0; /* Kirkwood is UP */
67
68	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
69
70	dev_dbg(priv.dev, "Attempting to set frequency to %i KHz\n",
71	kirkwood_freq_table[index].frequency);
72	dev_dbg(priv.dev, "old frequency was %i KHz\n",
73	kirkwood_cpufreq_get_cpu_frequency(0));
74
75	if (freqs.old != freqs.new) {
76	local_irq_disable();
77
78	/* Disable interrupts to the CPU */
79	reg = readl_relaxed(priv.base);
80	reg \|= CPU_SW_INT_BLK;
81	writel_relaxed(reg, priv.base);
82
83	switch (state) {
84	case STATE_CPU_FREQ:
85	clk_disable(priv.powersave_clk);
86	break;
87	case STATE_DDR_FREQ:
88	clk_enable(priv.powersave_clk);
89	break;
90	}
91
92	/* Wait-for-Interrupt, while the hardware changes frequency */
93	cpu_do_idle();
94
95	/* Enable interrupts to the CPU */
96	reg = readl_relaxed(priv.base);
97	reg &= ~CPU_SW_INT_BLK;
98	writel_relaxed(reg, priv.base);
99
100	local_irq_enable();
101	}
102	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
103	};
104
105	static int kirkwood_cpufreq_verify(struct cpufreq_policy *policy)
106	{
107	return cpufreq_frequency_table_verify(policy, kirkwood_freq_table);
108	}
109
110	static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,
111	unsigned int target_freq,
112	unsigned int relation)
113	{
114	unsigned int index = 0;
115
116	if (cpufreq_frequency_table_target(policy, kirkwood_freq_table,
117	target_freq, relation, &index))
118	return -EINVAL;
119
120	kirkwood_cpufreq_set_cpu_state(index);
121
122	return 0;
123	}
124
125	/* Module init and exit code */
126	static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
127	{
128	int result;
129
130	/* cpuinfo and default policy values */
131	policy->cpuinfo.transition_latency = 5000; /* 5uS */
132	policy->cur = kirkwood_cpufreq_get_cpu_frequency(0);
133
134	result = cpufreq_frequency_table_cpuinfo(policy, kirkwood_freq_table);
135	if (result)
136	return result;
137
138	cpufreq_frequency_table_get_attr(kirkwood_freq_table, policy->cpu);
139
140	return 0;
141	}
142
143	static int kirkwood_cpufreq_cpu_exit(struct cpufreq_policy *policy)
144	{
145	cpufreq_frequency_table_put_attr(policy->cpu);
146	return 0;
147	}
148
149	static struct freq_attr *kirkwood_cpufreq_attr[] = {
150	&cpufreq_freq_attr_scaling_available_freqs,
151	NULL,
152	};
153
154	static struct cpufreq_driver kirkwood_cpufreq_driver = {
155	.get = kirkwood_cpufreq_get_cpu_frequency,
156	.verify = kirkwood_cpufreq_verify,
157	.target = kirkwood_cpufreq_target,
158	.init = kirkwood_cpufreq_cpu_init,
159	.exit = kirkwood_cpufreq_cpu_exit,
160	.name = "kirkwood-cpufreq",
161	.owner = THIS_MODULE,
162	.attr = kirkwood_cpufreq_attr,
163	};
164
165	static int kirkwood_cpufreq_probe(struct platform_device *pdev)
166	{
167	struct device_node *np;
168	struct resource *res;
169	int err;
170
171	priv.dev = &pdev->dev;
172
173	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
174	if (!res) {
175	dev_err(&pdev->dev, "Cannot get memory resource\n");
176	return -ENODEV;
177	}
178	priv.base = devm_request_and_ioremap(&pdev->dev, res);
179	if (!priv.base) {
180	dev_err(&pdev->dev, "Cannot ioremap\n");
181	return -EADDRNOTAVAIL;
182	}
183
184	np = of_find_node_by_path("/cpus/cpu@0");
185	if (!np)
186	return -ENODEV;
187
188	priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk");
189	if (IS_ERR(priv.cpu_clk)) {
190	dev_err(priv.dev, "Unable to get cpuclk");
191	return PTR_ERR(priv.cpu_clk);
192	}
193
194	clk_prepare_enable(priv.cpu_clk);
195	kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000;
196
197	priv.ddr_clk = of_clk_get_by_name(np, "ddrclk");
198	if (IS_ERR(priv.ddr_clk)) {
199	dev_err(priv.dev, "Unable to get ddrclk");
200	err = PTR_ERR(priv.ddr_clk);
201	goto out_cpu;
202	}
203
204	clk_prepare_enable(priv.ddr_clk);
205	kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000;
206
207	priv.powersave_clk = of_clk_get_by_name(np, "powersave");
208	if (IS_ERR(priv.powersave_clk)) {
209	dev_err(priv.dev, "Unable to get powersave");
210	err = PTR_ERR(priv.powersave_clk);
211	goto out_ddr;
212	}
213	clk_prepare(priv.powersave_clk);
214
215	of_node_put(np);
216	np = NULL;
217
218	err = cpufreq_register_driver(&kirkwood_cpufreq_driver);
219	if (!err)
220	return 0;
221
222	dev_err(priv.dev, "Failed to register cpufreq driver");
223
224	clk_disable_unprepare(priv.powersave_clk);
225	out_ddr:
226	clk_disable_unprepare(priv.ddr_clk);
227	out_cpu:
228	clk_disable_unprepare(priv.cpu_clk);
229	of_node_put(np);
230
231	return err;
232	}
233
234	static int kirkwood_cpufreq_remove(struct platform_device *pdev)
235	{
236	cpufreq_unregister_driver(&kirkwood_cpufreq_driver);
237
238	clk_disable_unprepare(priv.powersave_clk);
239	clk_disable_unprepare(priv.ddr_clk);
240	clk_disable_unprepare(priv.cpu_clk);
241
242	return 0;
243	}
244
245	static struct platform_driver kirkwood_cpufreq_platform_driver = {
246	.probe = kirkwood_cpufreq_probe,
247	.remove = kirkwood_cpufreq_remove,
248	.driver = {
249	.name = "kirkwood-cpufreq",
250	.owner = THIS_MODULE,
251	},
252	};
253
254	module_platform_driver(kirkwood_cpufreq_platform_driver);
255
256	MODULE_LICENSE("GPL v2");
257	MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
258	MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");
259	MODULE_ALIAS("platform:kirkwood-cpufreq");