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 | #include <linux/iopoll.h> |
17 | |
18 | #define RNG_DATA 0x00 |
19 | #define RNG_S4_DATA 0x08 |
20 | #define RNG_S4_CFG 0x00 |
21 | |
22 | #define RUN_BIT BIT(0) |
23 | #define SEED_READY_STS_BIT BIT(31) |
24 | |
25 | struct meson_rng_priv { |
26 | int (*read)(struct hwrng *rng, void *buf, size_t max, bool wait); |
27 | }; |
28 | |
29 | struct meson_rng_data { |
30 | void __iomem *base; |
31 | struct hwrng rng; |
32 | struct device *dev; |
33 | }; |
34 | |
35 | static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
36 | { |
37 | struct meson_rng_data *data = |
38 | container_of(rng, struct meson_rng_data, rng); |
39 | |
40 | *(u32 *)buf = readl_relaxed(data->base + RNG_DATA); |
41 | |
42 | return sizeof(u32); |
43 | } |
44 | |
45 | static int meson_rng_wait_status(void __iomem *cfg_addr, int bit) |
46 | { |
47 | u32 status = 0; |
48 | int ret; |
49 | |
50 | ret = readl_relaxed_poll_timeout_atomic(cfg_addr, |
51 | status, !(status & bit), |
52 | 10, 10000); |
53 | if (ret) |
54 | return -EBUSY; |
55 | |
56 | return 0; |
57 | } |
58 | |
59 | static int meson_s4_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) |
60 | { |
61 | struct meson_rng_data *data = |
62 | container_of(rng, struct meson_rng_data, rng); |
63 | |
64 | void __iomem *cfg_addr = data->base + RNG_S4_CFG; |
65 | int err; |
66 | |
67 | writel_relaxed(readl_relaxed(cfg_addr) | SEED_READY_STS_BIT, cfg_addr); |
68 | |
69 | err = meson_rng_wait_status(cfg_addr, SEED_READY_STS_BIT); |
70 | if (err) { |
71 | dev_err(data->dev, "Seed isn't ready, try again\n" ); |
72 | return err; |
73 | } |
74 | |
75 | err = meson_rng_wait_status(cfg_addr, RUN_BIT); |
76 | if (err) { |
77 | dev_err(data->dev, "Can't get random number, try again\n" ); |
78 | return err; |
79 | } |
80 | |
81 | *(u32 *)buf = readl_relaxed(data->base + RNG_S4_DATA); |
82 | |
83 | return sizeof(u32); |
84 | } |
85 | |
86 | static int meson_rng_probe(struct platform_device *pdev) |
87 | { |
88 | struct device *dev = &pdev->dev; |
89 | struct meson_rng_data *data; |
90 | struct clk *core_clk; |
91 | const struct meson_rng_priv *priv; |
92 | |
93 | data = devm_kzalloc(dev, size: sizeof(*data), GFP_KERNEL); |
94 | if (!data) |
95 | return -ENOMEM; |
96 | |
97 | priv = device_get_match_data(dev: &pdev->dev); |
98 | if (!priv) |
99 | return -ENODEV; |
100 | |
101 | data->base = devm_platform_ioremap_resource(pdev, index: 0); |
102 | if (IS_ERR(ptr: data->base)) |
103 | return PTR_ERR(ptr: data->base); |
104 | |
105 | core_clk = devm_clk_get_optional_enabled(dev, id: "core" ); |
106 | if (IS_ERR(ptr: core_clk)) |
107 | return dev_err_probe(dev, err: PTR_ERR(ptr: core_clk), |
108 | fmt: "Failed to get core clock\n" ); |
109 | |
110 | data->rng.name = pdev->name; |
111 | data->rng.read = priv->read; |
112 | |
113 | data->dev = &pdev->dev; |
114 | |
115 | return devm_hwrng_register(dev, rng: &data->rng); |
116 | } |
117 | |
118 | static const struct meson_rng_priv meson_rng_priv = { |
119 | .read = meson_rng_read, |
120 | }; |
121 | |
122 | static const struct meson_rng_priv meson_rng_priv_s4 = { |
123 | .read = meson_s4_rng_read, |
124 | }; |
125 | |
126 | static const struct of_device_id meson_rng_of_match[] = { |
127 | { |
128 | .compatible = "amlogic,meson-rng" , |
129 | .data = (void *)&meson_rng_priv, |
130 | }, |
131 | { |
132 | .compatible = "amlogic,meson-s4-rng" , |
133 | .data = (void *)&meson_rng_priv_s4, |
134 | }, |
135 | {}, |
136 | }; |
137 | MODULE_DEVICE_TABLE(of, meson_rng_of_match); |
138 | |
139 | static struct platform_driver meson_rng_driver = { |
140 | .probe = meson_rng_probe, |
141 | .driver = { |
142 | .name = "meson-rng" , |
143 | .of_match_table = meson_rng_of_match, |
144 | }, |
145 | }; |
146 | |
147 | module_platform_driver(meson_rng_driver); |
148 | |
149 | MODULE_DESCRIPTION("Meson H/W Random Number Generator driver" ); |
150 | MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>" ); |
151 | MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>" ); |
152 | MODULE_LICENSE("Dual BSD/GPL" ); |
153 | |