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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 | ||
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 | ||
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 | ||
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 | ||
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 | ||
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"); |