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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
25struct meson_rng_priv {
26 int (*read)(struct hwrng *rng, void *buf, size_t max, bool wait);
27};
28
29struct meson_rng_data {
30 void __iomem *base;
31 struct hwrng rng;
32 struct device *dev;
33};
34
35static 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
45static 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
59static 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
86static 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, sizeof(*data), GFP_KERNEL);
94 if (!data)
95 return -ENOMEM;
96
97 priv = device_get_match_data(&pdev->dev);
98 if (!priv)
99 return -ENODEV;
100
101 data->base = devm_platform_ioremap_resource(pdev, 0);
102 if (IS_ERR(data->base))
103 return PTR_ERR(data->base);
104
105 core_clk = devm_clk_get_optional_enabled(dev, "core");
106 if (IS_ERR(core_clk))
107 return dev_err_probe(dev, PTR_ERR(core_clk),
108 "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, &data->rng);
116}
117
118static const struct meson_rng_priv meson_rng_priv = {
119 .read = meson_rng_read,
120};
121
122static const struct meson_rng_priv meson_rng_priv_s4 = {
123 .read = meson_s4_rng_read,
124};
125
126static 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};
137MODULE_DEVICE_TABLE(of, meson_rng_of_match);
138
139static 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
147module_platform_driver(meson_rng_driver);
148
149MODULE_DESCRIPTION("Meson H/W Random Number Generator driver");
150MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>");
151MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
152MODULE_LICENSE("Dual BSD/GPL");
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
19struct meson_rng_data {
20 void __iomem *base;
21 struct platform_device *pdev;
22 struct hwrng rng;
23 struct clk *core_clk;
24};
25
26static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
27{
28 struct meson_rng_data *data =
29 container_of(rng, struct meson_rng_data, rng);
30
31 *(u32 *)buf = readl_relaxed(data->base + RNG_DATA);
32
33 return sizeof(u32);
34}
35
36static void meson_rng_clk_disable(void *data)
37{
38 clk_disable_unprepare(data);
39}
40
41static int meson_rng_probe(struct platform_device *pdev)
42{
43 struct device *dev = &pdev->dev;
44 struct meson_rng_data *data;
45 int ret;
46
47 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
48 if (!data)
49 return -ENOMEM;
50
51 data->pdev = pdev;
52
53 data->base = devm_platform_ioremap_resource(pdev, 0);
54 if (IS_ERR(data->base))
55 return PTR_ERR(data->base);
56
57 data->core_clk = devm_clk_get_optional(dev, "core");
58 if (IS_ERR(data->core_clk))
59 return dev_err_probe(dev, PTR_ERR(data->core_clk),
60 "Failed to get core clock\n");
61
62 if (data->core_clk) {
63 ret = clk_prepare_enable(data->core_clk);
64 if (ret)
65 return ret;
66 ret = devm_add_action_or_reset(dev, meson_rng_clk_disable,
67 data->core_clk);
68 if (ret)
69 return ret;
70 }
71
72 data->rng.name = pdev->name;
73 data->rng.read = meson_rng_read;
74
75 platform_set_drvdata(pdev, data);
76
77 return devm_hwrng_register(dev, &data->rng);
78}
79
80static const struct of_device_id meson_rng_of_match[] = {
81 { .compatible = "amlogic,meson-rng", },
82 {},
83};
84MODULE_DEVICE_TABLE(of, meson_rng_of_match);
85
86static struct platform_driver meson_rng_driver = {
87 .probe = meson_rng_probe,
88 .driver = {
89 .name = "meson-rng",
90 .of_match_table = meson_rng_of_match,
91 },
92};
93
94module_platform_driver(meson_rng_driver);
95
96MODULE_DESCRIPTION("Meson H/W Random Number Generator driver");
97MODULE_AUTHOR("Lawrence Mok <lawrence.mok@amlogic.com>");
98MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
99MODULE_LICENSE("Dual BSD/GPL");