Commit | Line | Data |
---|---|---|
d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
afc39d6e KW |
2 | /* |
3 | * Copyright (C) 2016 HiSilicon Co., Ltd. | |
afc39d6e KW |
4 | */ |
5 | ||
6 | #include <linux/err.h> | |
7 | #include <linux/kernel.h> | |
8 | #include <linux/hw_random.h> | |
9 | #include <linux/io.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/of.h> | |
12 | #include <linux/platform_device.h> | |
13 | #include <linux/random.h> | |
14 | ||
15 | #define RNG_SEED 0x0 | |
16 | #define RNG_CTRL 0x4 | |
17 | #define RNG_SEED_SEL BIT(2) | |
18 | #define RNG_RING_EN BIT(1) | |
19 | #define RNG_EN BIT(0) | |
20 | #define RNG_RAN_NUM 0x10 | |
21 | #define RNG_PHY_SEED 0x14 | |
22 | ||
23 | #define to_hisi_rng(p) container_of(p, struct hisi_rng, rng) | |
24 | ||
25 | static int seed_sel; | |
26 | module_param(seed_sel, int, S_IRUGO); | |
27 | MODULE_PARM_DESC(seed_sel, "Auto reload seed. 0, use LFSR(default); 1, use ring oscillator."); | |
28 | ||
29 | struct hisi_rng { | |
30 | void __iomem *base; | |
31 | struct hwrng rng; | |
32 | }; | |
33 | ||
34 | static int hisi_rng_init(struct hwrng *rng) | |
35 | { | |
36 | struct hisi_rng *hrng = to_hisi_rng(rng); | |
37 | int val = RNG_EN; | |
38 | u32 seed; | |
39 | ||
40 | /* get a random number as initial seed */ | |
41 | get_random_bytes(&seed, sizeof(seed)); | |
42 | ||
43 | writel_relaxed(seed, hrng->base + RNG_SEED); | |
44 | ||
45 | /** | |
46 | * The seed is reload periodically, there are two choice | |
47 | * of seeds, default seed using the value from LFSR, or | |
48 | * will use seed generated by ring oscillator. | |
49 | */ | |
50 | if (seed_sel == 1) | |
51 | val |= RNG_RING_EN | RNG_SEED_SEL; | |
52 | ||
53 | writel_relaxed(val, hrng->base + RNG_CTRL); | |
54 | return 0; | |
55 | } | |
56 | ||
57 | static void hisi_rng_cleanup(struct hwrng *rng) | |
58 | { | |
59 | struct hisi_rng *hrng = to_hisi_rng(rng); | |
60 | ||
61 | writel_relaxed(0, hrng->base + RNG_CTRL); | |
62 | } | |
63 | ||
64 | static int hisi_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) | |
65 | { | |
66 | struct hisi_rng *hrng = to_hisi_rng(rng); | |
67 | u32 *data = buf; | |
68 | ||
69 | *data = readl_relaxed(hrng->base + RNG_RAN_NUM); | |
70 | return 4; | |
71 | } | |
72 | ||
73 | static int hisi_rng_probe(struct platform_device *pdev) | |
74 | { | |
75 | struct hisi_rng *rng; | |
afc39d6e KW |
76 | int ret; |
77 | ||
78 | rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); | |
79 | if (!rng) | |
80 | return -ENOMEM; | |
81 | ||
82 | platform_set_drvdata(pdev, rng); | |
83 | ||
10304c76 | 84 | rng->base = devm_platform_ioremap_resource(pdev, 0); |
afc39d6e KW |
85 | if (IS_ERR(rng->base)) |
86 | return PTR_ERR(rng->base); | |
87 | ||
88 | rng->rng.name = pdev->name; | |
89 | rng->rng.init = hisi_rng_init; | |
90 | rng->rng.cleanup = hisi_rng_cleanup; | |
91 | rng->rng.read = hisi_rng_read; | |
92 | ||
93 | ret = devm_hwrng_register(&pdev->dev, &rng->rng); | |
94 | if (ret) { | |
95 | dev_err(&pdev->dev, "failed to register hwrng\n"); | |
96 | return ret; | |
97 | } | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
eb515c60 | 102 | static const struct of_device_id hisi_rng_dt_ids[] __maybe_unused = { |
afc39d6e KW |
103 | { .compatible = "hisilicon,hip04-rng" }, |
104 | { .compatible = "hisilicon,hip05-rng" }, | |
105 | { } | |
106 | }; | |
107 | MODULE_DEVICE_TABLE(of, hisi_rng_dt_ids); | |
108 | ||
109 | static struct platform_driver hisi_rng_driver = { | |
110 | .probe = hisi_rng_probe, | |
111 | .driver = { | |
112 | .name = "hisi-rng", | |
113 | .of_match_table = of_match_ptr(hisi_rng_dt_ids), | |
114 | }, | |
115 | }; | |
116 | ||
117 | module_platform_driver(hisi_rng_driver); | |
118 | ||
119 | MODULE_LICENSE("GPL"); | |
120 | MODULE_AUTHOR("Kefeng Wang <wangkefeng.wang@huawei>"); | |
121 | MODULE_DESCRIPTION("Hisilicon random number generator driver"); |