[linux-block.git] / drivers / char / hw_random / ingenic-trng.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Ingenic True Random Number Generator driver
 * Copyright (c) 2019 漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>
 * Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
 */

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/hw_random.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

/* DTRNG register offsets */
#define TRNG_REG_CFG_OFFSET			0x00
#define TRNG_REG_RANDOMNUM_OFFSET	0x04
#define TRNG_REG_STATUS_OFFSET		0x08

/* bits within the CFG register */
#define CFG_RDY_CLR					BIT(12)
#define CFG_INT_MASK				BIT(11)
#define CFG_GEN_EN					BIT(0)

/* bits within the STATUS register */
#define STATUS_RANDOM_RDY			BIT(0)

struct ingenic_trng {
	void __iomem *base;
	struct clk *clk;
	struct hwrng rng;
};

static int ingenic_trng_init(struct hwrng *rng)
{
	struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
	unsigned int ctrl;

	ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
	ctrl |= CFG_GEN_EN;
	writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);

	return 0;
}

static void ingenic_trng_cleanup(struct hwrng *rng)
{
	struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
	unsigned int ctrl;

	ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
	ctrl &= ~CFG_GEN_EN;
	writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
}

static int ingenic_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
{
	struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
	u32 *data = buf;
	u32 status;
	int ret;

	ret = readl_poll_timeout(trng->base + TRNG_REG_STATUS_OFFSET, status,
				 status & STATUS_RANDOM_RDY, 10, 1000);
	if (ret == -ETIMEDOUT) {
		pr_err("%s: Wait for DTRNG data ready timeout\n", __func__);
		return ret;
	}

	*data = readl(trng->base + TRNG_REG_RANDOMNUM_OFFSET);

	return 4;
}

static int ingenic_trng_probe(struct platform_device *pdev)
{
	struct ingenic_trng *trng;
	int ret;

	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
	if (!trng)
		return -ENOMEM;

	trng->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(trng->base)) {
		pr_err("%s: Failed to map DTRNG registers\n", __func__);
		ret = PTR_ERR(trng->base);
		return PTR_ERR(trng->base);
	}

	trng->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(trng->clk)) {
		ret = PTR_ERR(trng->clk);
		pr_crit("%s: Cannot get DTRNG clock\n", __func__);
		return PTR_ERR(trng->clk);
	}

	ret = clk_prepare_enable(trng->clk);
	if (ret) {
		pr_crit("%s: Unable to enable DTRNG clock\n", __func__);
		return ret;
	}

	trng->rng.name = pdev->name;
	trng->rng.init = ingenic_trng_init;
	trng->rng.cleanup = ingenic_trng_cleanup;
	trng->rng.read = ingenic_trng_read;

	ret = hwrng_register(&trng->rng);
	if (ret) {
		dev_err(&pdev->dev, "Failed to register hwrng\n");
		return ret;
	}

	platform_set_drvdata(pdev, trng);

	dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n");
	return 0;
}

static int ingenic_trng_remove(struct platform_device *pdev)
{
	struct ingenic_trng *trng = platform_get_drvdata(pdev);
	unsigned int ctrl;

	hwrng_unregister(&trng->rng);

	ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
	ctrl &= ~CFG_GEN_EN;
	writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);

	clk_disable_unprepare(trng->clk);

	return 0;
}

static const struct of_device_id ingenic_trng_of_match[] = {
	{ .compatible = "ingenic,x1830-dtrng" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, ingenic_trng_of_match);

static struct platform_driver ingenic_trng_driver = {
	.probe		= ingenic_trng_probe,
	.remove		= ingenic_trng_remove,
	.driver		= {
		.name	= "ingenic-trng",
		.of_match_table = ingenic_trng_of_match,
	},
};

module_platform_driver(ingenic_trng_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>");
MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>");
MODULE_DESCRIPTION("Ingenic True Random Number Generator driver");
Commit	Line	Data
406346d2 ZY	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Ingenic True Random Number Generator driver
	4	* Copyright (c) 2019 漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>
	5	* Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
	6	*/
	7
	8	#include <linux/clk.h>
	9	#include <linux/err.h>
	10	#include <linux/kernel.h>
	11	#include <linux/hw_random.h>
	12	#include <linux/io.h>
	13	#include <linux/iopoll.h>
	14	#include <linux/module.h>
	15	#include <linux/of_device.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/slab.h>
	18
	19	/* DTRNG register offsets */
	20	#define TRNG_REG_CFG_OFFSET 0x00
	21	#define TRNG_REG_RANDOMNUM_OFFSET 0x04
	22	#define TRNG_REG_STATUS_OFFSET 0x08
	23
	24	/* bits within the CFG register */
	25	#define CFG_RDY_CLR BIT(12)
	26	#define CFG_INT_MASK BIT(11)
	27	#define CFG_GEN_EN BIT(0)
	28
	29	/* bits within the STATUS register */
	30	#define STATUS_RANDOM_RDY BIT(0)
	31
	32	struct ingenic_trng {
	33	void __iomem *base;
	34	struct clk *clk;
	35	struct hwrng rng;
	36	};
	37
	38	static int ingenic_trng_init(struct hwrng *rng)
	39	{
	40	struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
	41	unsigned int ctrl;
	42
	43	ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
	44	ctrl \|= CFG_GEN_EN;
	45	writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
	46
	47	return 0;
	48	}
	49
	50	static void ingenic_trng_cleanup(struct hwrng *rng)
	51	{
	52	struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
	53	unsigned int ctrl;
	54
	55	ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
	56	ctrl &= ~CFG_GEN_EN;
	57	writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
	58	}
	59
	60	static int ingenic_trng_read(struct hwrng rng, void buf, size_t max, bool wait)
	61	{
	62	struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng);
	63	u32 *data = buf;
	64	u32 status;
65	int ret;
66
67	ret = readl_poll_timeout(trng->base + TRNG_REG_STATUS_OFFSET, status,
68	status & STATUS_RANDOM_RDY, 10, 1000);
69	if (ret == -ETIMEDOUT) {
70	pr_err("%s: Wait for DTRNG data ready timeout\n", __func__);
71	return ret;
72	}
73
74	*data = readl(trng->base + TRNG_REG_RANDOMNUM_OFFSET);
75
76	return 4;
77	}
78
79	static int ingenic_trng_probe(struct platform_device *pdev)
80	{
81	struct ingenic_trng *trng;
82	int ret;
83
84	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
85	if (!trng)
86	return -ENOMEM;
87
88	trng->base = devm_platform_ioremap_resource(pdev, 0);
89	if (IS_ERR(trng->base)) {
90	pr_err("%s: Failed to map DTRNG registers\n", __func__);
91	ret = PTR_ERR(trng->base);
92	return PTR_ERR(trng->base);
93	}
94
95	trng->clk = devm_clk_get(&pdev->dev, NULL);
96	if (IS_ERR(trng->clk)) {
97	ret = PTR_ERR(trng->clk);
98	pr_crit("%s: Cannot get DTRNG clock\n", __func__);
99	return PTR_ERR(trng->clk);
100	}
101
102	ret = clk_prepare_enable(trng->clk);
103	if (ret) {
104	pr_crit("%s: Unable to enable DTRNG clock\n", __func__);
105	return ret;
106	}
107
108	trng->rng.name = pdev->name;
109	trng->rng.init = ingenic_trng_init;
110	trng->rng.cleanup = ingenic_trng_cleanup;
111	trng->rng.read = ingenic_trng_read;
112
113	ret = hwrng_register(&trng->rng);
114	if (ret) {
115	dev_err(&pdev->dev, "Failed to register hwrng\n");
116	return ret;
117	}
118
119	platform_set_drvdata(pdev, trng);
120
121	dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n");
122	return 0;
123	}
124
125	static int ingenic_trng_remove(struct platform_device *pdev)
126	{
127	struct ingenic_trng *trng = platform_get_drvdata(pdev);
128	unsigned int ctrl;
129
130	hwrng_unregister(&trng->rng);
131
132	ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET);
133	ctrl &= ~CFG_GEN_EN;
134	writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET);
135
136	clk_disable_unprepare(trng->clk);
137
138	return 0;
139	}
140
141	static const struct of_device_id ingenic_trng_of_match[] = {
142	{ .compatible = "ingenic,x1830-dtrng" },
143	{ /* sentinel */ }
144	};
145	MODULE_DEVICE_TABLE(of, ingenic_trng_of_match);
146
147	static struct platform_driver ingenic_trng_driver = {
148	.probe = ingenic_trng_probe,
149	.remove = ingenic_trng_remove,
150	.driver = {
151	.name = "ingenic-trng",
152	.of_match_table = ingenic_trng_of_match,
153	},
154	};
155
156	module_platform_driver(ingenic_trng_driver);
157
158	MODULE_LICENSE("GPL");
159	MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>");
160	MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>");
161	MODULE_DESCRIPTION("Ingenic True Random Number Generator driver");