[linux-2.6-block.git] / drivers / cpufreq / loongson1-cpufreq.c

/*
 * CPU Frequency Scaling for Loongson 1 SoC
 *
 * Copyright (C) 2014-2016 Zhang, Keguang <keguang.zhang@gmail.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.
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <cpufreq.h>
#include <loongson1.h>

struct ls1x_cpufreq {
	struct device *dev;
	struct clk *clk;	/* CPU clk */
	struct clk *mux_clk;	/* MUX of CPU clk */
	struct clk *pll_clk;	/* PLL clk */
	struct clk *osc_clk;	/* OSC clk */
	unsigned int max_freq;
	unsigned int min_freq;
};

static struct ls1x_cpufreq *cpufreq;

static int ls1x_cpufreq_notifier(struct notifier_block *nb,
				 unsigned long val, void *data)
{
	if (val == CPUFREQ_POSTCHANGE)
		current_cpu_data.udelay_val = loops_per_jiffy;

	return NOTIFY_OK;
}

static struct notifier_block ls1x_cpufreq_notifier_block = {
	.notifier_call = ls1x_cpufreq_notifier
};

static int ls1x_cpufreq_target(struct cpufreq_policy *policy,
			       unsigned int index)
{
	struct device *cpu_dev = get_cpu_device(policy->cpu);
	unsigned int old_freq, new_freq;

	old_freq = policy->cur;
	new_freq = policy->freq_table[index].frequency;

	/*
	 * The procedure of reconfiguring CPU clk is as below.
	 *
	 *  - Reparent CPU clk to OSC clk
	 *  - Reset CPU clock (very important)
	 *  - Reconfigure CPU DIV
	 *  - Reparent CPU clk back to CPU DIV clk
	 */

	clk_set_parent(policy->clk, cpufreq->osc_clk);
	__raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) | RST_CPU_EN | RST_CPU,
		     LS1X_CLK_PLL_DIV);
	__raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) & ~(RST_CPU_EN | RST_CPU),
		     LS1X_CLK_PLL_DIV);
	clk_set_rate(cpufreq->mux_clk, new_freq * 1000);
	clk_set_parent(policy->clk, cpufreq->mux_clk);
	dev_dbg(cpu_dev, "%u KHz --> %u KHz\n", old_freq, new_freq);

	return 0;
}

static int ls1x_cpufreq_init(struct cpufreq_policy *policy)
{
	struct device *cpu_dev = get_cpu_device(policy->cpu);
	struct cpufreq_frequency_table *freq_tbl;
	unsigned int pll_freq, freq;
	int steps, i, ret;

	pll_freq = clk_get_rate(cpufreq->pll_clk) / 1000;

	steps = 1 << DIV_CPU_WIDTH;
	freq_tbl = kcalloc(steps, sizeof(*freq_tbl), GFP_KERNEL);
	if (!freq_tbl)
		return -ENOMEM;

	for (i = 0; i < (steps - 1); i++) {
		freq = pll_freq / (i + 1);
		if ((freq < cpufreq->min_freq) || (freq > cpufreq->max_freq))
			freq_tbl[i].frequency = CPUFREQ_ENTRY_INVALID;
		else
			freq_tbl[i].frequency = freq;
		dev_dbg(cpu_dev,
			"cpufreq table: index %d: frequency %d\n", i,
			freq_tbl[i].frequency);
	}
	freq_tbl[i].frequency = CPUFREQ_TABLE_END;

	policy->clk = cpufreq->clk;
	ret = cpufreq_generic_init(policy, freq_tbl, 0);
	if (ret)
		kfree(freq_tbl);

	return ret;
}

static int ls1x_cpufreq_exit(struct cpufreq_policy *policy)
{
	kfree(policy->freq_table);
	return 0;
}

static struct cpufreq_driver ls1x_cpufreq_driver = {
	.name		= "cpufreq-ls1x",
	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
	.verify		= cpufreq_generic_frequency_table_verify,
	.target_index	= ls1x_cpufreq_target,
	.get		= cpufreq_generic_get,
	.init		= ls1x_cpufreq_init,
	.exit		= ls1x_cpufreq_exit,
	.attr		= cpufreq_generic_attr,
};

static int ls1x_cpufreq_remove(struct platform_device *pdev)
{
	cpufreq_unregister_notifier(&ls1x_cpufreq_notifier_block,
				    CPUFREQ_TRANSITION_NOTIFIER);
	cpufreq_unregister_driver(&ls1x_cpufreq_driver);

	return 0;
}

static int ls1x_cpufreq_probe(struct platform_device *pdev)
{
	struct plat_ls1x_cpufreq *pdata = dev_get_platdata(&pdev->dev);
	struct clk *clk;
	int ret;

	if (!pdata || !pdata->clk_name || !pdata->osc_clk_name) {
		dev_err(&pdev->dev, "platform data missing\n");
		return -EINVAL;
	}

	cpufreq =
	    devm_kzalloc(&pdev->dev, sizeof(struct ls1x_cpufreq), GFP_KERNEL);
	if (!cpufreq)
		return -ENOMEM;

	cpufreq->dev = &pdev->dev;

	clk = devm_clk_get(&pdev->dev, pdata->clk_name);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "unable to get %s clock\n",
			pdata->clk_name);
		return PTR_ERR(clk);
	}
	cpufreq->clk = clk;

	clk = clk_get_parent(clk);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "unable to get parent of %s clock\n",
			__clk_get_name(cpufreq->clk));
		return PTR_ERR(clk);
	}
	cpufreq->mux_clk = clk;

	clk = clk_get_parent(clk);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "unable to get parent of %s clock\n",
			__clk_get_name(cpufreq->mux_clk));
		return PTR_ERR(clk);
	}
	cpufreq->pll_clk = clk;

	clk = devm_clk_get(&pdev->dev, pdata->osc_clk_name);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "unable to get %s clock\n",
			pdata->osc_clk_name);
		return PTR_ERR(clk);
	}
	cpufreq->osc_clk = clk;

	cpufreq->max_freq = pdata->max_freq;
	cpufreq->min_freq = pdata->min_freq;

	ret = cpufreq_register_driver(&ls1x_cpufreq_driver);
	if (ret) {
		dev_err(&pdev->dev,
			"failed to register CPUFreq driver: %d\n", ret);
		return ret;
	}

	ret = cpufreq_register_notifier(&ls1x_cpufreq_notifier_block,
					CPUFREQ_TRANSITION_NOTIFIER);

	if (ret) {
		dev_err(&pdev->dev,
			"failed to register CPUFreq notifier: %d\n",ret);
		cpufreq_unregister_driver(&ls1x_cpufreq_driver);
	}

	return ret;
}

static struct platform_driver ls1x_cpufreq_platdrv = {
	.probe	= ls1x_cpufreq_probe,
	.remove	= ls1x_cpufreq_remove,
	.driver	= {
		.name	= "ls1x-cpufreq",
	},
};

module_platform_driver(ls1x_cpufreq_platdrv);

MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>");
MODULE_DESCRIPTION("Loongson1 CPUFreq driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
a0a22cf1 KC	1	/*
	2	* CPU Frequency Scaling for Loongson 1 SoC
	3	*
6a1d55cc	4	* Copyright (C) 2014-2016 Zhang, Keguang <keguang.zhang@gmail.com>
a0a22cf1 KC	5	*
	6	* This file is licensed under the terms of the GNU General Public
	7	* License version 2. This program is licensed "as is" without any
	8	* warranty of any kind, whether express or implied.
	9	*/
	10
	11	#include <linux/clk.h>
	12	#include <linux/clk-provider.h>
	13	#include <linux/cpu.h>
	14	#include <linux/cpufreq.h>
	15	#include <linux/delay.h>
62e59c4e	16	#include <linux/io.h>
a0a22cf1 KC	17	#include <linux/module.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/slab.h>
	20
30ad29bb HC	21	#include <cpufreq.h>
30ad29bb HC	22	#include <loongson1.h>
a0a22cf1	23
99bf2e68	24	struct ls1x_cpufreq {
a0a22cf1 KC	25	struct device *dev;
	26	struct clk clk; / CPU clk */
	27	struct clk mux_clk; / MUX of CPU clk */
	28	struct clk pll_clk; / PLL clk */
	29	struct clk osc_clk; / OSC clk */
	30	unsigned int max_freq;
	31	unsigned int min_freq;
99bf2e68 KC	32	};
	33
	34	static struct ls1x_cpufreq *cpufreq;
a0a22cf1 KC	35
	36	static int ls1x_cpufreq_notifier(struct notifier_block *nb,
	37	unsigned long val, void *data)
	38	{
	39	if (val == CPUFREQ_POSTCHANGE)
	40	current_cpu_data.udelay_val = loops_per_jiffy;
	41
	42	return NOTIFY_OK;
	43	}
	44
	45	static struct notifier_block ls1x_cpufreq_notifier_block = {
	46	.notifier_call = ls1x_cpufreq_notifier
	47	};
	48
	49	static int ls1x_cpufreq_target(struct cpufreq_policy *policy,
	50	unsigned int index)
	51	{
99bf2e68	52	struct device *cpu_dev = get_cpu_device(policy->cpu);
a0a22cf1 KC	53	unsigned int old_freq, new_freq;
	54
	55	old_freq = policy->cur;
	56	new_freq = policy->freq_table[index].frequency;
	57
	58	/*
	59	* The procedure of reconfiguring CPU clk is as below.
	60	*
	61	* - Reparent CPU clk to OSC clk
	62	* - Reset CPU clock (very important)
	63	* - Reconfigure CPU DIV
	64	* - Reparent CPU clk back to CPU DIV clk
	65	*/
	66
99bf2e68	67	clk_set_parent(policy->clk, cpufreq->osc_clk);
a0a22cf1 KC	68	__raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) \| RST_CPU_EN \| RST_CPU,
	69	LS1X_CLK_PLL_DIV);
	70	__raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) & ~(RST_CPU_EN \| RST_CPU),
	71	LS1X_CLK_PLL_DIV);
99bf2e68 KC	72	clk_set_rate(cpufreq->mux_clk, new_freq * 1000);
	73	clk_set_parent(policy->clk, cpufreq->mux_clk);
	74	dev_dbg(cpu_dev, "%u KHz --> %u KHz\n", old_freq, new_freq);
a0a22cf1 KC	75
	76	return 0;
	77	}
	78
	79	static int ls1x_cpufreq_init(struct cpufreq_policy *policy)
	80	{
99bf2e68	81	struct device *cpu_dev = get_cpu_device(policy->cpu);
a0a22cf1 KC	82	struct cpufreq_frequency_table *freq_tbl;
	83	unsigned int pll_freq, freq;
	84	int steps, i, ret;
	85
99bf2e68	86	pll_freq = clk_get_rate(cpufreq->pll_clk) / 1000;
a0a22cf1 KC	87
a0a22cf1 KC	88	steps = 1 << DIV_CPU_WIDTH;
379e38a7 KC	89	freq_tbl = kcalloc(steps, sizeof(*freq_tbl), GFP_KERNEL);
	90	if (!freq_tbl)
	91	return -ENOMEM;
a0a22cf1 KC	92
	93	for (i = 0; i < (steps - 1); i++) {
	94	freq = pll_freq / (i + 1);
99bf2e68	95	if ((freq < cpufreq->min_freq) \|\| (freq > cpufreq->max_freq))
a0a22cf1 KC	96	freq_tbl[i].frequency = CPUFREQ_ENTRY_INVALID;
	97	else
	98	freq_tbl[i].frequency = freq;
99bf2e68	99	dev_dbg(cpu_dev,
a0a22cf1 KC	100	"cpufreq table: index %d: frequency %d\n", i,
	101	freq_tbl[i].frequency);
	102	}
	103	freq_tbl[i].frequency = CPUFREQ_TABLE_END;
	104
99bf2e68	105	policy->clk = cpufreq->clk;
a0a22cf1 KC	106	ret = cpufreq_generic_init(policy, freq_tbl, 0);
	107	if (ret)
	108	kfree(freq_tbl);
379e38a7	109
a0a22cf1 KC	110	return ret;
	111	}
	112
	113	static int ls1x_cpufreq_exit(struct cpufreq_policy *policy)
	114	{
	115	kfree(policy->freq_table);
	116	return 0;
	117	}
	118
	119	static struct cpufreq_driver ls1x_cpufreq_driver = {
	120	.name = "cpufreq-ls1x",
	121	.flags = CPUFREQ_STICKY \| CPUFREQ_NEED_INITIAL_FREQ_CHECK,
	122	.verify = cpufreq_generic_frequency_table_verify,
	123	.target_index = ls1x_cpufreq_target,
	124	.get = cpufreq_generic_get,
	125	.init = ls1x_cpufreq_init,
	126	.exit = ls1x_cpufreq_exit,
	127	.attr = cpufreq_generic_attr,
	128	};
	129
	130	static int ls1x_cpufreq_remove(struct platform_device *pdev)
	131	{
	132	cpufreq_unregister_notifier(&ls1x_cpufreq_notifier_block,
	133	CPUFREQ_TRANSITION_NOTIFIER);
	134	cpufreq_unregister_driver(&ls1x_cpufreq_driver);
	135
	136	return 0;
	137	}
	138
	139	static int ls1x_cpufreq_probe(struct platform_device *pdev)
	140	{
25581d2b	141	struct plat_ls1x_cpufreq *pdata = dev_get_platdata(&pdev->dev);
a0a22cf1 KC	142	struct clk *clk;
	143	int ret;
	144
65b2849a KC	145	if (!pdata \|\| !pdata->clk_name \|\| !pdata->osc_clk_name) {
65b2849a KC	146	dev_err(&pdev->dev, "platform data missing\n");
a0a22cf1	147	return -EINVAL;
65b2849a	148	}
a0a22cf1	149
99bf2e68 KC	150	cpufreq =
	151	devm_kzalloc(&pdev->dev, sizeof(struct ls1x_cpufreq), GFP_KERNEL);
	152	if (!cpufreq)
	153	return -ENOMEM;
	154
	155	cpufreq->dev = &pdev->dev;
a0a22cf1 KC	156
	157	clk = devm_clk_get(&pdev->dev, pdata->clk_name);
	158	if (IS_ERR(clk)) {
99bf2e68	159	dev_err(&pdev->dev, "unable to get %s clock\n",
a0a22cf1	160	pdata->clk_name);
65b2849a	161	return PTR_ERR(clk);
a0a22cf1	162	}
99bf2e68	163	cpufreq->clk = clk;
a0a22cf1 KC	164
	165	clk = clk_get_parent(clk);
	166	if (IS_ERR(clk)) {
99bf2e68 KC	167	dev_err(&pdev->dev, "unable to get parent of %s clock\n",
99bf2e68 KC	168	__clk_get_name(cpufreq->clk));
65b2849a	169	return PTR_ERR(clk);
a0a22cf1	170	}
99bf2e68	171	cpufreq->mux_clk = clk;
a0a22cf1 KC	172
	173	clk = clk_get_parent(clk);
	174	if (IS_ERR(clk)) {
99bf2e68 KC	175	dev_err(&pdev->dev, "unable to get parent of %s clock\n",
99bf2e68 KC	176	__clk_get_name(cpufreq->mux_clk));
65b2849a	177	return PTR_ERR(clk);
a0a22cf1	178	}
99bf2e68	179	cpufreq->pll_clk = clk;
a0a22cf1 KC	180
	181	clk = devm_clk_get(&pdev->dev, pdata->osc_clk_name);
	182	if (IS_ERR(clk)) {
99bf2e68	183	dev_err(&pdev->dev, "unable to get %s clock\n",
a0a22cf1	184	pdata->osc_clk_name);
65b2849a	185	return PTR_ERR(clk);
a0a22cf1	186	}
99bf2e68	187	cpufreq->osc_clk = clk;
a0a22cf1	188
99bf2e68 KC	189	cpufreq->max_freq = pdata->max_freq;
99bf2e68 KC	190	cpufreq->min_freq = pdata->min_freq;
a0a22cf1 KC	191
	192	ret = cpufreq_register_driver(&ls1x_cpufreq_driver);
	193	if (ret) {
99bf2e68 KC	194	dev_err(&pdev->dev,
99bf2e68 KC	195	"failed to register CPUFreq driver: %d\n", ret);
65b2849a	196	return ret;
a0a22cf1 KC	197	}
	198
	199	ret = cpufreq_register_notifier(&ls1x_cpufreq_notifier_block,
	200	CPUFREQ_TRANSITION_NOTIFIER);
	201
65b2849a KC	202	if (ret) {
	203	dev_err(&pdev->dev,
	204	"failed to register CPUFreq notifier: %d\n",ret);
	205	cpufreq_unregister_driver(&ls1x_cpufreq_driver);
	206	}
a0a22cf1	207
a0a22cf1 KC	208	return ret;
	209	}
	210
	211	static struct platform_driver ls1x_cpufreq_platdrv = {
6a1d55cc KC	212	.probe = ls1x_cpufreq_probe,
	213	.remove = ls1x_cpufreq_remove,
	214	.driver = {
a0a22cf1	215	.name = "ls1x-cpufreq",
a0a22cf1	216	},
a0a22cf1 KC	217	};
	218
	219	module_platform_driver(ls1x_cpufreq_platdrv);
	220
	221	MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>");
6a1d55cc	222	MODULE_DESCRIPTION("Loongson1 CPUFreq driver");
a0a22cf1	223	MODULE_LICENSE("GPL");