1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (c) 2016 BayLibre, SAS.
4*4882a593Smuzhiyun * Author: Neil Armstrong <narmstrong@baylibre.com>
5*4882a593Smuzhiyun * Copyright (C) 2014 Amlogic, Inc.
6*4882a593Smuzhiyun */
7*4882a593Smuzhiyun #include <linux/err.h>
8*4882a593Smuzhiyun #include <linux/module.h>
9*4882a593Smuzhiyun #include <linux/io.h>
10*4882a593Smuzhiyun #include <linux/platform_device.h>
11*4882a593Smuzhiyun #include <linux/hw_random.h>
12*4882a593Smuzhiyun #include <linux/slab.h>
13*4882a593Smuzhiyun #include <linux/types.h>
14*4882a593Smuzhiyun #include <linux/of.h>
15*4882a593Smuzhiyun #include <linux/clk.h>
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun #define RNG_DATA 0x00
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun struct meson_rng_data {
20*4882a593Smuzhiyun void __iomem *base;
21*4882a593Smuzhiyun struct platform_device *pdev;
22*4882a593Smuzhiyun struct hwrng rng;
23*4882a593Smuzhiyun struct clk *core_clk;
24*4882a593Smuzhiyun };
25*4882a593Smuzhiyun
meson_rng_read(struct hwrng * rng,void * buf,size_t max,bool wait)26*4882a593Smuzhiyun static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
27*4882a593Smuzhiyun {
28*4882a593Smuzhiyun struct meson_rng_data *data =
29*4882a593Smuzhiyun container_of(rng, struct meson_rng_data, rng);
30*4882a593Smuzhiyun
31*4882a593Smuzhiyun *(u32 *)buf = readl_relaxed(data->base + RNG_DATA);
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun return sizeof(u32);
34*4882a593Smuzhiyun }
35*4882a593Smuzhiyun
meson_rng_clk_disable(void * data)36*4882a593Smuzhiyun static void meson_rng_clk_disable(void *data)
37*4882a593Smuzhiyun {
38*4882a593Smuzhiyun clk_disable_unprepare(data);
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun
meson_rng_probe(struct platform_device * pdev)41*4882a593Smuzhiyun static int meson_rng_probe(struct platform_device *pdev)
42*4882a593Smuzhiyun {
43*4882a593Smuzhiyun struct device *dev = &pdev->dev;
44*4882a593Smuzhiyun struct meson_rng_data *data;
45*4882a593Smuzhiyun int ret;
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
48*4882a593Smuzhiyun if (!data)
49*4882a593Smuzhiyun return -ENOMEM;
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun data->pdev = pdev;
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun data->base = devm_platform_ioremap_resource(pdev, 0);
54*4882a593Smuzhiyun if (IS_ERR(data->base))
55*4882a593Smuzhiyun return PTR_ERR(data->base);
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun data->core_clk = devm_clk_get(dev, "core");
58*4882a593Smuzhiyun if (IS_ERR(data->core_clk))
59*4882a593Smuzhiyun data->core_clk = NULL;
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun if (data->core_clk) {
62*4882a593Smuzhiyun ret = clk_prepare_enable(data->core_clk);
63*4882a593Smuzhiyun if (ret)
64*4882a593Smuzhiyun return ret;
65*4882a593Smuzhiyun ret = devm_add_action_or_reset(dev, meson_rng_clk_disable,
66*4882a593Smuzhiyun data->core_clk);
67*4882a593Smuzhiyun if (ret)
68*4882a593Smuzhiyun return ret;
69*4882a593Smuzhiyun }
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun data->rng.name = pdev->name;
72*4882a593Smuzhiyun data->rng.read = meson_rng_read;
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun platform_set_drvdata(pdev, data);
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun return devm_hwrng_register(dev, &data->rng);
77*4882a593Smuzhiyun }
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun static const struct of_device_id meson_rng_of_match[] = {
80*4882a593Smuzhiyun { .compatible = "amlogic,meson-rng", },
81*4882a593Smuzhiyun {},
82*4882a593Smuzhiyun };
83*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, meson_rng_of_match);
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun static struct platform_driver meson_rng_driver = {
86*4882a593Smuzhiyun .probe = meson_rng_probe,
87*4882a593Smuzhiyun .driver = {
88*4882a593Smuzhiyun .name = "meson-rng",
89*4882a593Smuzhiyun .of_match_table = meson_rng_of_match,
90*4882a593Smuzhiyun },
91*4882a593Smuzhiyun };
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun module_platform_driver(meson_rng_driver);
94*4882a593Smuzhiyun
95*4882a593Smuzhiyun MODULE_DESCRIPTION("Meson H/W Random Number Generator driver");
96*4882a593Smuzhiyun MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>");
97*4882a593Smuzhiyun MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
98*4882a593Smuzhiyun MODULE_LICENSE("Dual BSD/GPL");
99