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 #include <linux/of.h>
16
17 #define RNG_CTRL 0x00
18 #define RNG_EN (1 << 0)
19
20 #define RNG_STAT 0x04
21 #define RNG_AVAIL_MASK (0xff000000)
22
23 #define RNG_DATA 0x08
24 #define RNG_THRES 0x0c
25 #define RNG_MASK 0x10
26
27 struct bcm63xx_rng_priv {
28 struct hwrng rng;
29 struct clk *clk;
30 void __iomem *regs;
31 };
32
33 #define to_rng_priv(rng) container_of(rng, struct bcm63xx_rng_priv, rng)
34
bcm63xx_rng_init(struct hwrng * rng)35 static int bcm63xx_rng_init(struct hwrng *rng)
36 {
37 struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
38 u32 val;
39 int error;
40
41 error = clk_prepare_enable(priv->clk);
42 if (error)
43 return error;
44
45 val = __raw_readl(priv->regs + RNG_CTRL);
46 val |= RNG_EN;
47 __raw_writel(val, priv->regs + RNG_CTRL);
48
49 return 0;
50 }
51
bcm63xx_rng_cleanup(struct hwrng * rng)52 static void bcm63xx_rng_cleanup(struct hwrng *rng)
53 {
54 struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
55 u32 val;
56
57 val = __raw_readl(priv->regs + RNG_CTRL);
58 val &= ~RNG_EN;
59 __raw_writel(val, priv->regs + RNG_CTRL);
60
61 clk_disable_unprepare(priv->clk);
62 }
63
bcm63xx_rng_data_present(struct hwrng * rng,int wait)64 static int bcm63xx_rng_data_present(struct hwrng *rng, int wait)
65 {
66 struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
67
68 return __raw_readl(priv->regs + RNG_STAT) & RNG_AVAIL_MASK;
69 }
70
bcm63xx_rng_data_read(struct hwrng * rng,u32 * data)71 static int bcm63xx_rng_data_read(struct hwrng *rng, u32 *data)
72 {
73 struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
74
75 *data = __raw_readl(priv->regs + RNG_DATA);
76
77 return 4;
78 }
79
bcm63xx_rng_probe(struct platform_device * pdev)80 static int bcm63xx_rng_probe(struct platform_device *pdev)
81 {
82 struct resource *r;
83 int ret;
84 struct bcm63xx_rng_priv *priv;
85
86 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
87 if (!r) {
88 dev_err(&pdev->dev, "no iomem resource\n");
89 return -ENXIO;
90 }
91
92 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
93 if (!priv)
94 return -ENOMEM;
95
96 priv->rng.name = pdev->name;
97 priv->rng.init = bcm63xx_rng_init;
98 priv->rng.cleanup = bcm63xx_rng_cleanup;
99 priv->rng.data_present = bcm63xx_rng_data_present;
100 priv->rng.data_read = bcm63xx_rng_data_read;
101
102 priv->clk = devm_clk_get(&pdev->dev, "ipsec");
103 if (IS_ERR(priv->clk)) {
104 ret = PTR_ERR(priv->clk);
105 dev_err(&pdev->dev, "no clock for device: %d\n", ret);
106 return ret;
107 }
108
109 if (!devm_request_mem_region(&pdev->dev, r->start,
110 resource_size(r), pdev->name)) {
111 dev_err(&pdev->dev, "request mem failed");
112 return -EBUSY;
113 }
114
115 priv->regs = devm_ioremap_nocache(&pdev->dev, r->start,
116 resource_size(r));
117 if (!priv->regs) {
118 dev_err(&pdev->dev, "ioremap failed");
119 return -ENOMEM;
120 }
121
122 ret = devm_hwrng_register(&pdev->dev, &priv->rng);
123 if (ret) {
124 dev_err(&pdev->dev, "failed to register rng device: %d\n",
125 ret);
126 return ret;
127 }
128
129 dev_info(&pdev->dev, "registered RNG driver\n");
130
131 return 0;
132 }
133
134 #ifdef CONFIG_OF
135 static const struct of_device_id bcm63xx_rng_of_match[] = {
136 { .compatible = "brcm,bcm6368-rng", },
137 {},
138 };
139 MODULE_DEVICE_TABLE(of, bcm63xx_rng_of_match);
140 #endif
141
142 static struct platform_driver bcm63xx_rng_driver = {
143 .probe = bcm63xx_rng_probe,
144 .driver = {
145 .name = "bcm63xx-rng",
146 .of_match_table = of_match_ptr(bcm63xx_rng_of_match),
147 },
148 };
149
150 module_platform_driver(bcm63xx_rng_driver);
151
152 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
153 MODULE_DESCRIPTION("Broadcom BCM63xx RNG driver");
154 MODULE_LICENSE("GPL");
155