1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (C) 2016 HiSilicon Co., Ltd.
4*4882a593Smuzhiyun */
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun #include <linux/err.h>
7*4882a593Smuzhiyun #include <linux/kernel.h>
8*4882a593Smuzhiyun #include <linux/hw_random.h>
9*4882a593Smuzhiyun #include <linux/io.h>
10*4882a593Smuzhiyun #include <linux/module.h>
11*4882a593Smuzhiyun #include <linux/of.h>
12*4882a593Smuzhiyun #include <linux/platform_device.h>
13*4882a593Smuzhiyun #include <linux/random.h>
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun #define RNG_SEED 0x0
16*4882a593Smuzhiyun #define RNG_CTRL 0x4
17*4882a593Smuzhiyun #define RNG_SEED_SEL BIT(2)
18*4882a593Smuzhiyun #define RNG_RING_EN BIT(1)
19*4882a593Smuzhiyun #define RNG_EN BIT(0)
20*4882a593Smuzhiyun #define RNG_RAN_NUM 0x10
21*4882a593Smuzhiyun #define RNG_PHY_SEED 0x14
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun #define to_hisi_rng(p) container_of(p, struct hisi_rng, rng)
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun static int seed_sel;
26*4882a593Smuzhiyun module_param(seed_sel, int, S_IRUGO);
27*4882a593Smuzhiyun MODULE_PARM_DESC(seed_sel, "Auto reload seed. 0, use LFSR(default); 1, use ring oscillator.");
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun struct hisi_rng {
30*4882a593Smuzhiyun void __iomem *base;
31*4882a593Smuzhiyun struct hwrng rng;
32*4882a593Smuzhiyun };
33*4882a593Smuzhiyun
hisi_rng_init(struct hwrng * rng)34*4882a593Smuzhiyun static int hisi_rng_init(struct hwrng *rng)
35*4882a593Smuzhiyun {
36*4882a593Smuzhiyun struct hisi_rng *hrng = to_hisi_rng(rng);
37*4882a593Smuzhiyun int val = RNG_EN;
38*4882a593Smuzhiyun u32 seed;
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun /* get a random number as initial seed */
41*4882a593Smuzhiyun get_random_bytes(&seed, sizeof(seed));
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun writel_relaxed(seed, hrng->base + RNG_SEED);
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun /**
46*4882a593Smuzhiyun * The seed is reload periodically, there are two choice
47*4882a593Smuzhiyun * of seeds, default seed using the value from LFSR, or
48*4882a593Smuzhiyun * will use seed generated by ring oscillator.
49*4882a593Smuzhiyun */
50*4882a593Smuzhiyun if (seed_sel == 1)
51*4882a593Smuzhiyun val |= RNG_RING_EN | RNG_SEED_SEL;
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun writel_relaxed(val, hrng->base + RNG_CTRL);
54*4882a593Smuzhiyun return 0;
55*4882a593Smuzhiyun }
56*4882a593Smuzhiyun
hisi_rng_cleanup(struct hwrng * rng)57*4882a593Smuzhiyun static void hisi_rng_cleanup(struct hwrng *rng)
58*4882a593Smuzhiyun {
59*4882a593Smuzhiyun struct hisi_rng *hrng = to_hisi_rng(rng);
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun writel_relaxed(0, hrng->base + RNG_CTRL);
62*4882a593Smuzhiyun }
63*4882a593Smuzhiyun
hisi_rng_read(struct hwrng * rng,void * buf,size_t max,bool wait)64*4882a593Smuzhiyun static int hisi_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
65*4882a593Smuzhiyun {
66*4882a593Smuzhiyun struct hisi_rng *hrng = to_hisi_rng(rng);
67*4882a593Smuzhiyun u32 *data = buf;
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun *data = readl_relaxed(hrng->base + RNG_RAN_NUM);
70*4882a593Smuzhiyun return 4;
71*4882a593Smuzhiyun }
72*4882a593Smuzhiyun
hisi_rng_probe(struct platform_device * pdev)73*4882a593Smuzhiyun static int hisi_rng_probe(struct platform_device *pdev)
74*4882a593Smuzhiyun {
75*4882a593Smuzhiyun struct hisi_rng *rng;
76*4882a593Smuzhiyun int ret;
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
79*4882a593Smuzhiyun if (!rng)
80*4882a593Smuzhiyun return -ENOMEM;
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun platform_set_drvdata(pdev, rng);
83*4882a593Smuzhiyun
84*4882a593Smuzhiyun rng->base = devm_platform_ioremap_resource(pdev, 0);
85*4882a593Smuzhiyun if (IS_ERR(rng->base))
86*4882a593Smuzhiyun return PTR_ERR(rng->base);
87*4882a593Smuzhiyun
88*4882a593Smuzhiyun rng->rng.name = pdev->name;
89*4882a593Smuzhiyun rng->rng.init = hisi_rng_init;
90*4882a593Smuzhiyun rng->rng.cleanup = hisi_rng_cleanup;
91*4882a593Smuzhiyun rng->rng.read = hisi_rng_read;
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun ret = devm_hwrng_register(&pdev->dev, &rng->rng);
94*4882a593Smuzhiyun if (ret) {
95*4882a593Smuzhiyun dev_err(&pdev->dev, "failed to register hwrng\n");
96*4882a593Smuzhiyun return ret;
97*4882a593Smuzhiyun }
98*4882a593Smuzhiyun
99*4882a593Smuzhiyun return 0;
100*4882a593Smuzhiyun }
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun static const struct of_device_id hisi_rng_dt_ids[] __maybe_unused = {
103*4882a593Smuzhiyun { .compatible = "hisilicon,hip04-rng" },
104*4882a593Smuzhiyun { .compatible = "hisilicon,hip05-rng" },
105*4882a593Smuzhiyun { }
106*4882a593Smuzhiyun };
107*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, hisi_rng_dt_ids);
108*4882a593Smuzhiyun
109*4882a593Smuzhiyun static struct platform_driver hisi_rng_driver = {
110*4882a593Smuzhiyun .probe = hisi_rng_probe,
111*4882a593Smuzhiyun .driver = {
112*4882a593Smuzhiyun .name = "hisi-rng",
113*4882a593Smuzhiyun .of_match_table = of_match_ptr(hisi_rng_dt_ids),
114*4882a593Smuzhiyun },
115*4882a593Smuzhiyun };
116*4882a593Smuzhiyun
117*4882a593Smuzhiyun module_platform_driver(hisi_rng_driver);
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun MODULE_LICENSE("GPL");
120*4882a593Smuzhiyun MODULE_AUTHOR("Kefeng Wang <wangkefeng.wang@huawei>");
121*4882a593Smuzhiyun MODULE_DESCRIPTION("Hisilicon random number generator driver");
122