[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_device.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(struct cpufreq_policy *policy,
		unsigned int index)
{
	struct cpufreq_freqs freqs;
	unsigned int state = kirkwood_freq_table[index].driver_data;
	unsigned long reg;

	freqs.old = kirkwood_cpufreq_get_cpu_frequency(0);
	freqs.new = kirkwood_freq_table[index].frequency;

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

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(policy, index);

	return 0;
}

/* Module init and exit code */
static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
	/* cpuinfo and default policy values */
	policy->cpuinfo.transition_latency = 5000; /* 5uS */

	return cpufreq_table_validate_and_show(policy, kirkwood_freq_table);
}

static struct cpufreq_driver kirkwood_cpufreq_driver = {
	.get	= kirkwood_cpufreq_get_cpu_frequency,
	.verify	= cpufreq_generic_frequency_table_verify,
	.target	= kirkwood_cpufreq_target,
	.init	= kirkwood_cpufreq_cpu_init,
	.exit	= cpufreq_generic_exit,
	.name	= "kirkwood-cpufreq",
	.attr	= cpufreq_generic_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);
	priv.base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(priv.base))
		return PTR_ERR(priv.base);

	np = of_cpu_device_node_get(0);
	if (!np) {
		dev_err(&pdev->dev, "failed to get cpu device node\n");
		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>
e768f350	17	#include <linux/of_device.h>
2a4bd9f0 AL	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
b43a7ffb VK	58	static void kirkwood_cpufreq_set_cpu_state(struct cpufreq_policy *policy,
b43a7ffb VK	59	unsigned int index)
2a4bd9f0 AL	60	{
2a4bd9f0 AL	61	struct cpufreq_freqs freqs;
50701588	62	unsigned int state = kirkwood_freq_table[index].driver_data;
2a4bd9f0 AL	63	unsigned long reg;
	64
	65	freqs.old = kirkwood_cpufreq_get_cpu_frequency(0);
	66	freqs.new = kirkwood_freq_table[index].frequency;
2a4bd9f0	67
b43a7ffb	68	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
2a4bd9f0 AL	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	}
b43a7ffb	102	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
2a4bd9f0 AL	103	};
2a4bd9f0 AL	104
2a4bd9f0 AL	105	static int kirkwood_cpufreq_target(struct cpufreq_policy *policy,
	106	unsigned int target_freq,
	107	unsigned int relation)
	108	{
	109	unsigned int index = 0;
	110
	111	if (cpufreq_frequency_table_target(policy, kirkwood_freq_table,
	112	target_freq, relation, &index))
	113	return -EINVAL;
	114
b43a7ffb	115	kirkwood_cpufreq_set_cpu_state(policy, index);
2a4bd9f0 AL	116
	117	return 0;
	118	}
	119
	120	/* Module init and exit code */
	121	static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy)
	122	{
2a4bd9f0 AL	123	/* cpuinfo and default policy values */
2a4bd9f0 AL	124	policy->cpuinfo.transition_latency = 5000; /* 5uS */
2a4bd9f0	125
6efbc777	126	return cpufreq_table_validate_and_show(policy, kirkwood_freq_table);
2a4bd9f0 AL	127	}
2a4bd9f0 AL	128
2a4bd9f0 AL	129	static struct cpufreq_driver kirkwood_cpufreq_driver = {
2a4bd9f0 AL	130	.get = kirkwood_cpufreq_get_cpu_frequency,
a86a41a1	131	.verify = cpufreq_generic_frequency_table_verify,
2a4bd9f0 AL	132	.target = kirkwood_cpufreq_target,
2a4bd9f0 AL	133	.init = kirkwood_cpufreq_cpu_init,
a86a41a1	134	.exit = cpufreq_generic_exit,
2a4bd9f0	135	.name = "kirkwood-cpufreq",
a86a41a1	136	.attr = cpufreq_generic_attr,
2a4bd9f0 AL	137	};
	138
	139	static int kirkwood_cpufreq_probe(struct platform_device *pdev)
	140	{
	141	struct device_node *np;
	142	struct resource *res;
	143	int err;
	144
	145	priv.dev = &pdev->dev;
	146
	147	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
cc721c4f SMP	148	priv.base = devm_ioremap_resource(&pdev->dev, res);
	149	if (IS_ERR(priv.base))
	150	return PTR_ERR(priv.base);
2a4bd9f0	151
e768f350 SK	152	np = of_cpu_device_node_get(0);
	153	if (!np) {
	154	dev_err(&pdev->dev, "failed to get cpu device node\n");
2a4bd9f0	155	return -ENODEV;
e768f350	156	}
2a4bd9f0 AL	157
	158	priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk");
	159	if (IS_ERR(priv.cpu_clk)) {
	160	dev_err(priv.dev, "Unable to get cpuclk");
	161	return PTR_ERR(priv.cpu_clk);
	162	}
	163
	164	clk_prepare_enable(priv.cpu_clk);
	165	kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000;
	166
	167	priv.ddr_clk = of_clk_get_by_name(np, "ddrclk");
	168	if (IS_ERR(priv.ddr_clk)) {
	169	dev_err(priv.dev, "Unable to get ddrclk");
	170	err = PTR_ERR(priv.ddr_clk);
	171	goto out_cpu;
	172	}
	173
	174	clk_prepare_enable(priv.ddr_clk);
	175	kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000;
	176
	177	priv.powersave_clk = of_clk_get_by_name(np, "powersave");
	178	if (IS_ERR(priv.powersave_clk)) {
	179	dev_err(priv.dev, "Unable to get powersave");
	180	err = PTR_ERR(priv.powersave_clk);
	181	goto out_ddr;
	182	}
	183	clk_prepare(priv.powersave_clk);
	184
	185	of_node_put(np);
	186	np = NULL;
	187
	188	err = cpufreq_register_driver(&kirkwood_cpufreq_driver);
	189	if (!err)
	190	return 0;
	191
	192	dev_err(priv.dev, "Failed to register cpufreq driver");
	193
	194	clk_disable_unprepare(priv.powersave_clk);
	195	out_ddr:
	196	clk_disable_unprepare(priv.ddr_clk);
	197	out_cpu:
	198	clk_disable_unprepare(priv.cpu_clk);
	199	of_node_put(np);
	200
	201	return err;
	202	}
	203
	204	static int kirkwood_cpufreq_remove(struct platform_device *pdev)
	205	{
	206	cpufreq_unregister_driver(&kirkwood_cpufreq_driver);
	207
	208	clk_disable_unprepare(priv.powersave_clk);
	209	clk_disable_unprepare(priv.ddr_clk);
	210	clk_disable_unprepare(priv.cpu_clk);
	211
	212	return 0;
	213	}
	214
	215	static struct platform_driver kirkwood_cpufreq_platform_driver = {
	216	.probe = kirkwood_cpufreq_probe,
	217	.remove = kirkwood_cpufreq_remove,
	218	.driver = {
	219	.name = "kirkwood-cpufreq",
	220	.owner = THIS_MODULE,
221	},
222	};
223
224	module_platform_driver(kirkwood_cpufreq_platform_driver);
225
226	MODULE_LICENSE("GPL v2");
227	MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
228	MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU");
229	MODULE_ALIAS("platform:kirkwood-cpufreq");