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