This source file includes following definitions.
- pic32_rng_read
- pic32_rng_probe
- pic32_rng_remove
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8
9 #include <linux/clk.h>
10 #include <linux/clkdev.h>
11 #include <linux/err.h>
12 #include <linux/hw_random.h>
13 #include <linux/io.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20
21 #define RNGCON 0x04
22 #define TRNGEN BIT(8)
23 #define PRNGEN BIT(9)
24 #define PRNGCONT BIT(10)
25 #define TRNGMOD BIT(11)
26 #define SEEDLOAD BIT(12)
27 #define RNGPOLY1 0x08
28 #define RNGPOLY2 0x0C
29 #define RNGNUMGEN1 0x10
30 #define RNGNUMGEN2 0x14
31 #define RNGSEED1 0x18
32 #define RNGSEED2 0x1C
33 #define RNGRCNT 0x20
34 #define RCNT_MASK 0x7F
35
36 struct pic32_rng {
37 void __iomem *base;
38 struct hwrng rng;
39 struct clk *clk;
40 };
41
42
43
44
45
46
47 #define RNG_TIMEOUT 500
48
49 static int pic32_rng_read(struct hwrng *rng, void *buf, size_t max,
50 bool wait)
51 {
52 struct pic32_rng *priv = container_of(rng, struct pic32_rng, rng);
53 u64 *data = buf;
54 u32 t;
55 unsigned int timeout = RNG_TIMEOUT;
56
57 do {
58 t = readl(priv->base + RNGRCNT) & RCNT_MASK;
59 if (t == 64) {
60
61 *data = ((u64)readl(priv->base + RNGSEED2) << 32) +
62 readl(priv->base + RNGSEED1);
63 return 8;
64 }
65 } while (wait && --timeout);
66
67 return -EIO;
68 }
69
70 static int pic32_rng_probe(struct platform_device *pdev)
71 {
72 struct pic32_rng *priv;
73 struct resource *res;
74 u32 v;
75 int ret;
76
77 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
78 if (!priv)
79 return -ENOMEM;
80
81 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
82 priv->base = devm_ioremap_resource(&pdev->dev, res);
83 if (IS_ERR(priv->base))
84 return PTR_ERR(priv->base);
85
86 priv->clk = devm_clk_get(&pdev->dev, NULL);
87 if (IS_ERR(priv->clk))
88 return PTR_ERR(priv->clk);
89
90 ret = clk_prepare_enable(priv->clk);
91 if (ret)
92 return ret;
93
94
95 v = TRNGEN | TRNGMOD;
96 writel(v, priv->base + RNGCON);
97
98 priv->rng.name = pdev->name;
99 priv->rng.read = pic32_rng_read;
100
101 ret = hwrng_register(&priv->rng);
102 if (ret)
103 goto err_register;
104
105 platform_set_drvdata(pdev, priv);
106
107 return 0;
108
109 err_register:
110 clk_disable_unprepare(priv->clk);
111 return ret;
112 }
113
114 static int pic32_rng_remove(struct platform_device *pdev)
115 {
116 struct pic32_rng *rng = platform_get_drvdata(pdev);
117
118 hwrng_unregister(&rng->rng);
119 writel(0, rng->base + RNGCON);
120 clk_disable_unprepare(rng->clk);
121 return 0;
122 }
123
124 static const struct of_device_id pic32_rng_of_match[] = {
125 { .compatible = "microchip,pic32mzda-rng", },
126 { }
127 };
128 MODULE_DEVICE_TABLE(of, pic32_rng_of_match);
129
130 static struct platform_driver pic32_rng_driver = {
131 .probe = pic32_rng_probe,
132 .remove = pic32_rng_remove,
133 .driver = {
134 .name = "pic32-rng",
135 .of_match_table = of_match_ptr(pic32_rng_of_match),
136 },
137 };
138
139 module_platform_driver(pic32_rng_driver);
140
141 MODULE_LICENSE("GPL");
142 MODULE_AUTHOR("Joshua Henderson <joshua.henderson@microchip.com>");
143 MODULE_DESCRIPTION("Microchip PIC32 RNG Driver");