[thirdparty/linux.git] / drivers / cpufreq / sun50i-cpufreq-nvmem.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Allwinner CPUFreq nvmem based driver
 *
 * The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to
 * provide the OPP framework with required information.
 *
 * Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/slab.h>

#define MAX_NAME_LEN	7

#define NVMEM_MASK	0x7
#define NVMEM_SHIFT	5

static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev;

/**
 * sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value
 * @versions: Set to the value parsed from efuse
 *
 * Returns 0 if success.
 */
static int sun50i_cpufreq_get_efuse(u32 *versions)
{
	struct nvmem_cell *speedbin_nvmem;
	struct device_node *np;
	struct device *cpu_dev;
	u32 *speedbin, efuse_value;
	size_t len;
	int ret;

	cpu_dev = get_cpu_device(0);
	if (!cpu_dev)
		return -ENODEV;

	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
	if (!np)
		return -ENOENT;

	ret = of_device_is_compatible(np,
				      "allwinner,sun50i-h6-operating-points");
	if (!ret) {
		of_node_put(np);
		return -ENOENT;
	}

	speedbin_nvmem = of_nvmem_cell_get(np, NULL);
	of_node_put(np);
	if (IS_ERR(speedbin_nvmem)) {
		if (PTR_ERR(speedbin_nvmem) != -EPROBE_DEFER)
			pr_err("Could not get nvmem cell: %ld\n",
			       PTR_ERR(speedbin_nvmem));
		return PTR_ERR(speedbin_nvmem);
	}

	speedbin = nvmem_cell_read(speedbin_nvmem, &len);
	nvmem_cell_put(speedbin_nvmem);
	if (IS_ERR(speedbin))
		return PTR_ERR(speedbin);

	efuse_value = (*speedbin >> NVMEM_SHIFT) & NVMEM_MASK;

	/*
	 * We treat unexpected efuse values as if the SoC was from
	 * the slowest bin. Expected efuse values are 1-3, slowest
	 * to fastest.
	 */
	if (efuse_value >= 1 && efuse_value <= 3)
		*versions = efuse_value - 1;
	else
		*versions = 0;

	kfree(speedbin);
	return 0;
};

static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
{
	struct opp_table **opp_tables;
	char name[MAX_NAME_LEN];
	unsigned int cpu;
	u32 speed = 0;
	int ret;

	opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
			     GFP_KERNEL);
	if (!opp_tables)
		return -ENOMEM;

	ret = sun50i_cpufreq_get_efuse(&speed);
	if (ret)
		return ret;

	snprintf(name, MAX_NAME_LEN, "speed%d", speed);

	for_each_possible_cpu(cpu) {
		struct device *cpu_dev = get_cpu_device(cpu);

		if (!cpu_dev) {
			ret = -ENODEV;
			goto free_opp;
		}

		opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
		if (IS_ERR(opp_tables[cpu])) {
			ret = PTR_ERR(opp_tables[cpu]);
			pr_err("Failed to set prop name\n");
			goto free_opp;
		}
	}

	cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
							  NULL, 0);
	if (!IS_ERR(cpufreq_dt_pdev)) {
		platform_set_drvdata(pdev, opp_tables);
		return 0;
	}

	ret = PTR_ERR(cpufreq_dt_pdev);
	pr_err("Failed to register platform device\n");

free_opp:
	for_each_possible_cpu(cpu) {
		if (IS_ERR_OR_NULL(opp_tables[cpu]))
			break;
		dev_pm_opp_put_prop_name(opp_tables[cpu]);
	}
	kfree(opp_tables);

	return ret;
}

static int sun50i_cpufreq_nvmem_remove(struct platform_device *pdev)
{
	struct opp_table **opp_tables = platform_get_drvdata(pdev);
	unsigned int cpu;

	platform_device_unregister(cpufreq_dt_pdev);

	for_each_possible_cpu(cpu)
		dev_pm_opp_put_prop_name(opp_tables[cpu]);

	kfree(opp_tables);

	return 0;
}

static struct platform_driver sun50i_cpufreq_driver = {
	.probe = sun50i_cpufreq_nvmem_probe,
	.remove = sun50i_cpufreq_nvmem_remove,
	.driver = {
		.name = "sun50i-cpufreq-nvmem",
	},
};

static const struct of_device_id sun50i_cpufreq_match_list[] = {
	{ .compatible = "allwinner,sun50i-h6" },
	{}
};

static const struct of_device_id *sun50i_cpufreq_match_node(void)
{
	const struct of_device_id *match;
	struct device_node *np;

	np = of_find_node_by_path("/");
	match = of_match_node(sun50i_cpufreq_match_list, np);
	of_node_put(np);

	return match;
}

/*
 * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
 * all the real activity is done in the probe, which may be defered as well.
 * The init here is only registering the driver and the platform device.
 */
static int __init sun50i_cpufreq_init(void)
{
	const struct of_device_id *match;
	int ret;

	match = sun50i_cpufreq_match_node();
	if (!match)
		return -ENODEV;

	ret = platform_driver_register(&sun50i_cpufreq_driver);
	if (unlikely(ret < 0))
		return ret;

	sun50i_cpufreq_pdev =
		platform_device_register_simple("sun50i-cpufreq-nvmem",
						-1, NULL, 0);
	ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev);
	if (ret == 0)
		return 0;

	platform_driver_unregister(&sun50i_cpufreq_driver);
	return ret;
}
module_init(sun50i_cpufreq_init);

static void __exit sun50i_cpufreq_exit(void)
{
	platform_device_unregister(sun50i_cpufreq_pdev);
	platform_driver_unregister(&sun50i_cpufreq_driver);
}
module_exit(sun50i_cpufreq_exit);

MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
f328584f YL	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Allwinner CPUFreq nvmem based driver
	4	*
	5	* The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to
	6	* provide the OPP framework with required information.
	7	*
	8	* Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com>
	9	*/
	10
	11	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	12
	13	#include <linux/module.h>
	14	#include <linux/nvmem-consumer.h>
	15	#include <linux/of_device.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/pm_opp.h>
	18	#include <linux/slab.h>
	19
	20	#define MAX_NAME_LEN 7
	21
	22	#define NVMEM_MASK 0x7
	23	#define NVMEM_SHIFT 5
	24
	25	static struct platform_device cpufreq_dt_pdev, sun50i_cpufreq_pdev;
	26
	27	/**
c2373448	28	* sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value
f328584f YL	29	* @versions: Set to the value parsed from efuse
	30	*
	31	* Returns 0 if success.
	32	*/
	33	static int sun50i_cpufreq_get_efuse(u32 *versions)
	34	{
	35	struct nvmem_cell *speedbin_nvmem;
	36	struct device_node *np;
	37	struct device *cpu_dev;
	38	u32 *speedbin, efuse_value;
	39	size_t len;
	40	int ret;
	41
	42	cpu_dev = get_cpu_device(0);
	43	if (!cpu_dev)
	44	return -ENODEV;
	45
	46	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
	47	if (!np)
	48	return -ENOENT;
	49
	50	ret = of_device_is_compatible(np,
	51	"allwinner,sun50i-h6-operating-points");
	52	if (!ret) {
	53	of_node_put(np);
	54	return -ENOENT;
	55	}
	56
	57	speedbin_nvmem = of_nvmem_cell_get(np, NULL);
	58	of_node_put(np);
	59	if (IS_ERR(speedbin_nvmem)) {
	60	if (PTR_ERR(speedbin_nvmem) != -EPROBE_DEFER)
	61	pr_err("Could not get nvmem cell: %ld\n",
	62	PTR_ERR(speedbin_nvmem));
	63	return PTR_ERR(speedbin_nvmem);
	64	}
	65
	66	speedbin = nvmem_cell_read(speedbin_nvmem, &len);
	67	nvmem_cell_put(speedbin_nvmem);
	68	if (IS_ERR(speedbin))
	69	return PTR_ERR(speedbin);
	70
	71	efuse_value = (*speedbin >> NVMEM_SHIFT) & NVMEM_MASK;
c2373448 OJ	72
	73	/*
	74	* We treat unexpected efuse values as if the SoC was from
	75	* the slowest bin. Expected efuse values are 1-3, slowest
	76	* to fastest.
	77	*/
	78	if (efuse_value >= 1 && efuse_value <= 3)
	79	*versions = efuse_value - 1;
	80	else
f328584f	81	*versions = 0;
f328584f YL	82
	83	kfree(speedbin);
	84	return 0;
	85	};
	86
	87	static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
	88	{
	89	struct opp_table **opp_tables;
	90	char name[MAX_NAME_LEN];
	91	unsigned int cpu;
	92	u32 speed = 0;
	93	int ret;
	94
	95	opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
	96	GFP_KERNEL);
	97	if (!opp_tables)
	98	return -ENOMEM;
	99
	100	ret = sun50i_cpufreq_get_efuse(&speed);
	101	if (ret)
	102	return ret;
	103
	104	snprintf(name, MAX_NAME_LEN, "speed%d", speed);
	105
	106	for_each_possible_cpu(cpu) {
	107	struct device *cpu_dev = get_cpu_device(cpu);
	108
	109	if (!cpu_dev) {
	110	ret = -ENODEV;
	111	goto free_opp;
	112	}
	113
	114	opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
	115	if (IS_ERR(opp_tables[cpu])) {
	116	ret = PTR_ERR(opp_tables[cpu]);
	117	pr_err("Failed to set prop name\n");
	118	goto free_opp;
	119	}
	120	}
	121
	122	cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
	123	NULL, 0);
	124	if (!IS_ERR(cpufreq_dt_pdev)) {
	125	platform_set_drvdata(pdev, opp_tables);
	126	return 0;
	127	}
	128
	129	ret = PTR_ERR(cpufreq_dt_pdev);
	130	pr_err("Failed to register platform device\n");
	131
	132	free_opp:
	133	for_each_possible_cpu(cpu) {
	134	if (IS_ERR_OR_NULL(opp_tables[cpu]))
	135	break;
	136	dev_pm_opp_put_prop_name(opp_tables[cpu]);
	137	}
	138	kfree(opp_tables);
	139
	140	return ret;
	141	}
	142
	143	static int sun50i_cpufreq_nvmem_remove(struct platform_device *pdev)
	144	{
	145	struct opp_table **opp_tables = platform_get_drvdata(pdev);
146	unsigned int cpu;
147
148	platform_device_unregister(cpufreq_dt_pdev);
149
150	for_each_possible_cpu(cpu)
151	dev_pm_opp_put_prop_name(opp_tables[cpu]);
152
153	kfree(opp_tables);
154
155	return 0;
156	}
157
158	static struct platform_driver sun50i_cpufreq_driver = {
159	.probe = sun50i_cpufreq_nvmem_probe,
160	.remove = sun50i_cpufreq_nvmem_remove,
161	.driver = {
162	.name = "sun50i-cpufreq-nvmem",
163	},
164	};
165
166	static const struct of_device_id sun50i_cpufreq_match_list[] = {
167	{ .compatible = "allwinner,sun50i-h6" },
168	{}
169	};
170
171	static const struct of_device_id *sun50i_cpufreq_match_node(void)
172	{
173	const struct of_device_id *match;
174	struct device_node *np;
175
176	np = of_find_node_by_path("/");
177	match = of_match_node(sun50i_cpufreq_match_list, np);
178	of_node_put(np);
179
180	return match;
181	}
182
183	/*
184	* Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
185	* all the real activity is done in the probe, which may be defered as well.
186	* The init here is only registering the driver and the platform device.
187	*/
188	static int __init sun50i_cpufreq_init(void)
189	{
190	const struct of_device_id *match;
191	int ret;
192
193	match = sun50i_cpufreq_match_node();
194	if (!match)
195	return -ENODEV;
196
197	ret = platform_driver_register(&sun50i_cpufreq_driver);
198	if (unlikely(ret < 0))
199	return ret;
200
201	sun50i_cpufreq_pdev =
202	platform_device_register_simple("sun50i-cpufreq-nvmem",
203	-1, NULL, 0);
204	ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev);
205	if (ret == 0)
206	return 0;
207
208	platform_driver_unregister(&sun50i_cpufreq_driver);
209	return ret;
210	}
211	module_init(sun50i_cpufreq_init);
212
213	static void __exit sun50i_cpufreq_exit(void)
214	{
215	platform_device_unregister(sun50i_cpufreq_pdev);
216	platform_driver_unregister(&sun50i_cpufreq_driver);
217	}
218	module_exit(sun50i_cpufreq_exit);
219
220	MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
221	MODULE_LICENSE("GPL v2");