1/*
2 * Broadcom BCM63xx Random Number Generator support
3 *
4 * Copyright (C) 2011, Florian Fainelli <florian@openwrt.org>
5 * Copyright (C) 2009, Broadcom Corporation
6 *
7 */
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/io.h>
11#include <linux/err.h>
12#include <linux/clk.h>
13#include <linux/platform_device.h>
14#include <linux/hw_random.h>
15
16#define RNG_CTRL			0x00
17#define RNG_EN				(1 << 0)
18
19#define RNG_STAT			0x04
20#define RNG_AVAIL_MASK			(0xff000000)
21
22#define RNG_DATA			0x08
23#define RNG_THRES			0x0c
24#define RNG_MASK			0x10
25
26struct bcm63xx_rng_priv {
27	struct hwrng rng;
28	struct clk *clk;
29	void __iomem *regs;
30};
31
32#define to_rng_priv(rng)	container_of(rng, struct bcm63xx_rng_priv, rng)
33
34static int bcm63xx_rng_init(struct hwrng *rng)
35{
36	struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
37	u32 val;
38	int error;
39
40	error = clk_prepare_enable(priv->clk);
41	if (error)
42		return error;
43
44	val = __raw_readl(priv->regs + RNG_CTRL);
45	val |= RNG_EN;
46	__raw_writel(val, priv->regs + RNG_CTRL);
47
48	return 0;
49}
50
51static void bcm63xx_rng_cleanup(struct hwrng *rng)
52{
53	struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
54	u32 val;
55
56	val = __raw_readl(priv->regs + RNG_CTRL);
57	val &= ~RNG_EN;
58	__raw_writel(val, priv->regs + RNG_CTRL);
59
60	clk_disable_unprepare(priv->clk);
61}
62
63static int bcm63xx_rng_data_present(struct hwrng *rng, int wait)
64{
65	struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
66
67	return __raw_readl(priv->regs + RNG_STAT) & RNG_AVAIL_MASK;
68}
69
70static int bcm63xx_rng_data_read(struct hwrng *rng, u32 *data)
71{
72	struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
73
74	*data = __raw_readl(priv->regs + RNG_DATA);
75
76	return 4;
77}
78
79static int bcm63xx_rng_probe(struct platform_device *pdev)
80{
81	struct resource *r;
82	struct clk *clk;
83	int ret;
84	struct bcm63xx_rng_priv *priv;
85	struct hwrng *rng;
86
87	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
88	if (!r) {
89		dev_err(&pdev->dev, "no iomem resource\n");
90		return -ENXIO;
91	}
92
93	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
94	if (!priv)
95		return -ENOMEM;
96
97	priv->rng.name = pdev->name;
98	priv->rng.init = bcm63xx_rng_init;
99	priv->rng.cleanup = bcm63xx_rng_cleanup;
100	priv->rng.data_present = bcm63xx_rng_data_present;
101	priv->rng.data_read = bcm63xx_rng_data_read;
102
103	priv->clk = devm_clk_get(&pdev->dev, "ipsec");
104	if (IS_ERR(priv->clk)) {
105		ret = PTR_ERR(priv->clk);
106		dev_err(&pdev->dev, "no clock for device: %d\n", ret);
107		return ret;
108	}
109
110	if (!devm_request_mem_region(&pdev->dev, r->start,
111					resource_size(r), pdev->name)) {
112		dev_err(&pdev->dev, "request mem failed");
113		return -EBUSY;
114	}
115
116	priv->regs = devm_ioremap_nocache(&pdev->dev, r->start,
117					resource_size(r));
118	if (!priv->regs) {
119		dev_err(&pdev->dev, "ioremap failed");
120		return -ENOMEM;
121	}
122
123	ret = devm_hwrng_register(&pdev->dev, &priv->rng);
124	if (ret) {
125		dev_err(&pdev->dev, "failed to register rng device: %d\n",
126			ret);
127		return ret;
128	}
129
130	dev_info(&pdev->dev, "registered RNG driver\n");
131
132	return 0;
133}
134
135static struct platform_driver bcm63xx_rng_driver = {
136	.probe		= bcm63xx_rng_probe,
137	.driver		= {
138		.name	= "bcm63xx-rng",
139	},
140};
141
142module_platform_driver(bcm63xx_rng_driver);
143
144MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
145MODULE_DESCRIPTION("Broadcom BCM63xx RNG driver");
146MODULE_LICENSE("GPL");
147