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
26 struct 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
bcm63xx_rng_init(struct hwrng * rng)34 static 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
bcm63xx_rng_cleanup(struct hwrng * rng)51 static 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
bcm63xx_rng_data_present(struct hwrng * rng,int wait)63 static 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
bcm63xx_rng_data_read(struct hwrng * rng,u32 * data)70 static 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
bcm63xx_rng_probe(struct platform_device * pdev)79 static 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
135 static struct platform_driver bcm63xx_rng_driver = {
136 .probe = bcm63xx_rng_probe,
137 .driver = {
138 .name = "bcm63xx-rng",
139 },
140 };
141
142 module_platform_driver(bcm63xx_rng_driver);
143
144 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
145 MODULE_DESCRIPTION("Broadcom BCM63xx RNG driver");
146 MODULE_LICENSE("GPL");
147