1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Ingenic Random Number Generator driver |
4 | * Copyright (c) 2017 PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> |
5 | * Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com> |
6 | */ |
7 | |
8 | #include <linux/err.h> |
9 | #include <linux/kernel.h> |
10 | #include <linux/hw_random.h> |
11 | #include <linux/io.h> |
12 | #include <linux/iopoll.h> |
13 | #include <linux/module.h> |
14 | #include <linux/of.h> |
15 | #include <linux/platform_device.h> |
16 | #include <linux/slab.h> |
17 | |
18 | /* RNG register offsets */ |
19 | #define RNG_REG_ERNG_OFFSET 0x0 |
20 | #define RNG_REG_RNG_OFFSET 0x4 |
21 | |
22 | /* bits within the ERND register */ |
23 | #define ERNG_READY BIT(31) |
24 | #define ERNG_ENABLE BIT(0) |
25 | |
26 | enum ingenic_rng_version { |
27 | ID_JZ4780, |
28 | ID_X1000, |
29 | }; |
30 | |
31 | /* Device associated memory */ |
32 | struct ingenic_rng { |
33 | enum ingenic_rng_version version; |
34 | |
35 | void __iomem *base; |
36 | struct hwrng rng; |
37 | }; |
38 | |
39 | static int ingenic_rng_init(struct hwrng *rng) |
40 | { |
41 | struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng); |
42 | |
43 | writel(ERNG_ENABLE, addr: priv->base + RNG_REG_ERNG_OFFSET); |
44 | |
45 | return 0; |
46 | } |
47 | |
48 | static void ingenic_rng_cleanup(struct hwrng *rng) |
49 | { |
50 | struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng); |
51 | |
52 | writel(val: 0, addr: priv->base + RNG_REG_ERNG_OFFSET); |
53 | } |
54 | |
55 | static int ingenic_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
56 | { |
57 | struct ingenic_rng *priv = container_of(rng, struct ingenic_rng, rng); |
58 | u32 *data = buf; |
59 | u32 status; |
60 | int ret; |
61 | |
62 | if (priv->version >= ID_X1000) { |
63 | ret = readl_poll_timeout(priv->base + RNG_REG_ERNG_OFFSET, status, |
64 | status & ERNG_READY, 10, 1000); |
65 | if (ret == -ETIMEDOUT) { |
66 | pr_err("%s: Wait for RNG data ready timeout\n" , __func__); |
67 | return ret; |
68 | } |
69 | } else { |
70 | /* |
71 | * A delay is required so that the current RNG data is not bit shifted |
72 | * version of previous RNG data which could happen if random data is |
73 | * read continuously from this device. |
74 | */ |
75 | udelay(20); |
76 | } |
77 | |
78 | *data = readl(addr: priv->base + RNG_REG_RNG_OFFSET); |
79 | |
80 | return 4; |
81 | } |
82 | |
83 | static int ingenic_rng_probe(struct platform_device *pdev) |
84 | { |
85 | struct ingenic_rng *priv; |
86 | int ret; |
87 | |
88 | priv = devm_kzalloc(dev: &pdev->dev, size: sizeof(*priv), GFP_KERNEL); |
89 | if (!priv) |
90 | return -ENOMEM; |
91 | |
92 | priv->base = devm_platform_ioremap_resource(pdev, index: 0); |
93 | if (IS_ERR(ptr: priv->base)) { |
94 | pr_err("%s: Failed to map RNG registers\n" , __func__); |
95 | return PTR_ERR(ptr: priv->base); |
96 | } |
97 | |
98 | priv->version = (enum ingenic_rng_version)(uintptr_t)of_device_get_match_data(dev: &pdev->dev); |
99 | |
100 | priv->rng.name = pdev->name; |
101 | priv->rng.init = ingenic_rng_init; |
102 | priv->rng.cleanup = ingenic_rng_cleanup; |
103 | priv->rng.read = ingenic_rng_read; |
104 | |
105 | ret = hwrng_register(rng: &priv->rng); |
106 | if (ret) { |
107 | dev_err(&pdev->dev, "Failed to register hwrng\n" ); |
108 | return ret; |
109 | } |
110 | |
111 | platform_set_drvdata(pdev, data: priv); |
112 | |
113 | dev_info(&pdev->dev, "Ingenic RNG driver registered\n" ); |
114 | return 0; |
115 | } |
116 | |
117 | static void ingenic_rng_remove(struct platform_device *pdev) |
118 | { |
119 | struct ingenic_rng *priv = platform_get_drvdata(pdev); |
120 | |
121 | hwrng_unregister(rng: &priv->rng); |
122 | |
123 | writel(val: 0, addr: priv->base + RNG_REG_ERNG_OFFSET); |
124 | } |
125 | |
126 | static const struct of_device_id ingenic_rng_of_match[] = { |
127 | { .compatible = "ingenic,jz4780-rng" , .data = (void *) ID_JZ4780 }, |
128 | { .compatible = "ingenic,x1000-rng" , .data = (void *) ID_X1000 }, |
129 | { /* sentinel */ } |
130 | }; |
131 | MODULE_DEVICE_TABLE(of, ingenic_rng_of_match); |
132 | |
133 | static struct platform_driver ingenic_rng_driver = { |
134 | .probe = ingenic_rng_probe, |
135 | .remove_new = ingenic_rng_remove, |
136 | .driver = { |
137 | .name = "ingenic-rng" , |
138 | .of_match_table = ingenic_rng_of_match, |
139 | }, |
140 | }; |
141 | |
142 | module_platform_driver(ingenic_rng_driver); |
143 | |
144 | MODULE_LICENSE("GPL" ); |
145 | MODULE_AUTHOR("PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>" ); |
146 | MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>" ); |
147 | MODULE_DESCRIPTION("Ingenic Random Number Generator driver" ); |
148 | |