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 #include <bcm63xx_io.h>
17 #include <bcm63xx_regs.h>
18
19 struct bcm63xx_rng_priv {
20 struct clk *clk;
21 void __iomem *regs;
22 };
23
24 #define to_rng_priv(rng) ((struct bcm63xx_rng_priv *)rng->priv)
25
bcm63xx_rng_init(struct hwrng * rng)26 static int bcm63xx_rng_init(struct hwrng *rng)
27 {
28 struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
29 u32 val;
30
31 val = bcm_readl(priv->regs + RNG_CTRL);
32 val |= RNG_EN;
33 bcm_writel(val, priv->regs + RNG_CTRL);
34
35 return 0;
36 }
37
bcm63xx_rng_cleanup(struct hwrng * rng)38 static void bcm63xx_rng_cleanup(struct hwrng *rng)
39 {
40 struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
41 u32 val;
42
43 val = bcm_readl(priv->regs + RNG_CTRL);
44 val &= ~RNG_EN;
45 bcm_writel(val, priv->regs + RNG_CTRL);
46 }
47
bcm63xx_rng_data_present(struct hwrng * rng,int wait)48 static int bcm63xx_rng_data_present(struct hwrng *rng, int wait)
49 {
50 struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
51
52 return bcm_readl(priv->regs + RNG_STAT) & RNG_AVAIL_MASK;
53 }
54
bcm63xx_rng_data_read(struct hwrng * rng,u32 * data)55 static int bcm63xx_rng_data_read(struct hwrng *rng, u32 *data)
56 {
57 struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
58
59 *data = bcm_readl(priv->regs + RNG_DATA);
60
61 return 4;
62 }
63
bcm63xx_rng_probe(struct platform_device * pdev)64 static int bcm63xx_rng_probe(struct platform_device *pdev)
65 {
66 struct resource *r;
67 struct clk *clk;
68 int ret;
69 struct bcm63xx_rng_priv *priv;
70 struct hwrng *rng;
71
72 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
73 if (!r) {
74 dev_err(&pdev->dev, "no iomem resource\n");
75 ret = -ENXIO;
76 goto out;
77 }
78
79 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
80 if (!priv) {
81 dev_err(&pdev->dev, "no memory for private structure\n");
82 ret = -ENOMEM;
83 goto out;
84 }
85
86 rng = kzalloc(sizeof(*rng), GFP_KERNEL);
87 if (!rng) {
88 dev_err(&pdev->dev, "no memory for rng structure\n");
89 ret = -ENOMEM;
90 goto out_free_priv;
91 }
92
93 platform_set_drvdata(pdev, rng);
94 rng->priv = (unsigned long)priv;
95 rng->name = pdev->name;
96 rng->init = bcm63xx_rng_init;
97 rng->cleanup = bcm63xx_rng_cleanup;
98 rng->data_present = bcm63xx_rng_data_present;
99 rng->data_read = bcm63xx_rng_data_read;
100
101 clk = clk_get(&pdev->dev, "ipsec");
102 if (IS_ERR(clk)) {
103 dev_err(&pdev->dev, "no clock for device\n");
104 ret = PTR_ERR(clk);
105 goto out_free_rng;
106 }
107
108 priv->clk = clk;
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 ret = -ENOMEM;
114 goto out_free_rng;
115 }
116
117 priv->regs = devm_ioremap_nocache(&pdev->dev, r->start,
118 resource_size(r));
119 if (!priv->regs) {
120 dev_err(&pdev->dev, "ioremap failed");
121 ret = -ENOMEM;
122 goto out_free_rng;
123 }
124
125 clk_enable(clk);
126
127 ret = hwrng_register(rng);
128 if (ret) {
129 dev_err(&pdev->dev, "failed to register rng device\n");
130 goto out_clk_disable;
131 }
132
133 dev_info(&pdev->dev, "registered RNG driver\n");
134
135 return 0;
136
137 out_clk_disable:
138 clk_disable(clk);
139 out_free_rng:
140 platform_set_drvdata(pdev, NULL);
141 kfree(rng);
142 out_free_priv:
143 kfree(priv);
144 out:
145 return ret;
146 }
147
bcm63xx_rng_remove(struct platform_device * pdev)148 static int bcm63xx_rng_remove(struct platform_device *pdev)
149 {
150 struct hwrng *rng = platform_get_drvdata(pdev);
151 struct bcm63xx_rng_priv *priv = to_rng_priv(rng);
152
153 hwrng_unregister(rng);
154 clk_disable(priv->clk);
155 kfree(priv);
156 kfree(rng);
157 platform_set_drvdata(pdev, NULL);
158
159 return 0;
160 }
161
162 static struct platform_driver bcm63xx_rng_driver = {
163 .probe = bcm63xx_rng_probe,
164 .remove = bcm63xx_rng_remove,
165 .driver = {
166 .name = "bcm63xx-rng",
167 .owner = THIS_MODULE,
168 },
169 };
170
171 module_platform_driver(bcm63xx_rng_driver);
172
173 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
174 MODULE_DESCRIPTION("Broadcom BCM63xx RNG driver");
175 MODULE_LICENSE("GPL");
176