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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2010-2012 Broadcom. All rights reserved.
4 * Copyright (c) 2013 Lubomir Rintel
5 */
6
7#include <linux/hw_random.h>
8#include <linux/io.h>
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/printk.h>
14#include <linux/clk.h>
15#include <linux/reset.h>
16
17#define RNG_CTRL 0x0
18#define RNG_STATUS 0x4
19#define RNG_DATA 0x8
20#define RNG_INT_MASK 0x10
21
22/* enable rng */
23#define RNG_RBGEN 0x1
24
25/* the initial numbers generated are "less random" so will be discarded */
26#define RNG_WARMUP_COUNT 0x40000
27
28#define RNG_INT_OFF 0x1
29
30struct bcm2835_rng_priv {
31 struct hwrng rng;
32 void __iomem *base;
33 bool mask_interrupts;
34 struct clk *clk;
35 struct reset_control *reset;
36};
37
38static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng)
39{
40 return container_of(rng, struct bcm2835_rng_priv, rng);
41}
42
43static inline u32 rng_readl(struct bcm2835_rng_priv *priv, u32 offset)
44{
45 /* MIPS chips strapped for BE will automagically configure the
46 * peripheral registers for CPU-native byte order.
47 */
48 if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
49 return __raw_readl(priv->base + offset);
50 else
51 return readl(priv->base + offset);
52}
53
54static inline void rng_writel(struct bcm2835_rng_priv *priv, u32 val,
55 u32 offset)
56{
57 if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
58 __raw_writel(val, priv->base + offset);
59 else
60 writel(val, priv->base + offset);
61}
62
63static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
64 bool wait)
65{
66 struct bcm2835_rng_priv *priv = to_rng_priv(rng);
67 u32 max_words = max / sizeof(u32);
68 u32 num_words, count;
69
70 while ((rng_readl(priv, RNG_STATUS) >> 24) == 0) {
71 if (!wait)
72 return 0;
73 hwrng_yield(rng);
74 }
75
76 num_words = rng_readl(priv, RNG_STATUS) >> 24;
77 if (num_words > max_words)
78 num_words = max_words;
79
80 for (count = 0; count < num_words; count++)
81 ((u32 *)buf)[count] = rng_readl(priv, RNG_DATA);
82
83 return num_words * sizeof(u32);
84}
85
86static int bcm2835_rng_init(struct hwrng *rng)
87{
88 struct bcm2835_rng_priv *priv = to_rng_priv(rng);
89 int ret = 0;
90 u32 val;
91
92 ret = clk_prepare_enable(priv->clk);
93 if (ret)
94 return ret;
95
96 ret = reset_control_reset(priv->reset);
97 if (ret)
98 return ret;
99
100 if (priv->mask_interrupts) {
101 /* mask the interrupt */
102 val = rng_readl(priv, RNG_INT_MASK);
103 val |= RNG_INT_OFF;
104 rng_writel(priv, val, RNG_INT_MASK);
105 }
106
107 /* set warm-up count & enable */
108 rng_writel(priv, RNG_WARMUP_COUNT, RNG_STATUS);
109 rng_writel(priv, RNG_RBGEN, RNG_CTRL);
110
111 return ret;
112}
113
114static void bcm2835_rng_cleanup(struct hwrng *rng)
115{
116 struct bcm2835_rng_priv *priv = to_rng_priv(rng);
117
118 /* disable rng hardware */
119 rng_writel(priv, 0, RNG_CTRL);
120
121 clk_disable_unprepare(priv->clk);
122}
123
124struct bcm2835_rng_of_data {
125 bool mask_interrupts;
126};
127
128static const struct bcm2835_rng_of_data nsp_rng_of_data = {
129 .mask_interrupts = true,
130};
131
132static const struct of_device_id bcm2835_rng_of_match[] = {
133 { .compatible = "brcm,bcm2835-rng"},
134 { .compatible = "brcm,bcm-nsp-rng", .data = &nsp_rng_of_data },
135 { .compatible = "brcm,bcm5301x-rng", .data = &nsp_rng_of_data },
136 { .compatible = "brcm,bcm6368-rng"},
137 {},
138};
139
140static int bcm2835_rng_probe(struct platform_device *pdev)
141{
142 const struct bcm2835_rng_of_data *of_data;
143 struct device *dev = &pdev->dev;
144 const struct of_device_id *rng_id;
145 struct bcm2835_rng_priv *priv;
146 int err;
147
148 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
149 if (!priv)
150 return -ENOMEM;
151
152 /* map peripheral */
153 priv->base = devm_platform_ioremap_resource(pdev, 0);
154 if (IS_ERR(priv->base))
155 return PTR_ERR(priv->base);
156
157 /* Clock is optional on most platforms */
158 priv->clk = devm_clk_get_optional(dev, NULL);
159 if (IS_ERR(priv->clk))
160 return PTR_ERR(priv->clk);
161
162 priv->reset = devm_reset_control_get_optional_exclusive(dev, NULL);
163 if (IS_ERR(priv->reset))
164 return PTR_ERR(priv->reset);
165
166 priv->rng.name = pdev->name;
167 priv->rng.init = bcm2835_rng_init;
168 priv->rng.read = bcm2835_rng_read;
169 priv->rng.cleanup = bcm2835_rng_cleanup;
170
171 if (dev_of_node(dev)) {
172 rng_id = of_match_node(bcm2835_rng_of_match, dev->of_node);
173 if (!rng_id)
174 return -EINVAL;
175
176 /* Check for rng init function, execute it */
177 of_data = rng_id->data;
178 if (of_data)
179 priv->mask_interrupts = of_data->mask_interrupts;
180 }
181
182 /* register driver */
183 err = devm_hwrng_register(dev, &priv->rng);
184 if (err)
185 dev_err(dev, "hwrng registration failed\n");
186 else
187 dev_info(dev, "hwrng registered\n");
188
189 return err;
190}
191
192MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match);
193
194static const struct platform_device_id bcm2835_rng_devtype[] = {
195 { .name = "bcm2835-rng" },
196 { .name = "bcm63xx-rng" },
197 { /* sentinel */ }
198};
199MODULE_DEVICE_TABLE(platform, bcm2835_rng_devtype);
200
201static struct platform_driver bcm2835_rng_driver = {
202 .driver = {
203 .name = "bcm2835-rng",
204 .of_match_table = bcm2835_rng_of_match,
205 },
206 .probe = bcm2835_rng_probe,
207 .id_table = bcm2835_rng_devtype,
208};
209module_platform_driver(bcm2835_rng_driver);
210
211MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
212MODULE_DESCRIPTION("BCM2835 Random Number Generator (RNG) driver");
213MODULE_LICENSE("GPL v2");
1/**
2 * Copyright (c) 2010-2012 Broadcom. All rights reserved.
3 * Copyright (c) 2013 Lubomir Rintel
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License ("GPL")
7 * version 2, as published by the Free Software Foundation.
8 */
9
10#include <linux/hw_random.h>
11#include <linux/io.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/of_address.h>
15#include <linux/of_platform.h>
16#include <linux/platform_device.h>
17#include <linux/printk.h>
18
19#define RNG_CTRL 0x0
20#define RNG_STATUS 0x4
21#define RNG_DATA 0x8
22#define RNG_INT_MASK 0x10
23
24/* enable rng */
25#define RNG_RBGEN 0x1
26
27/* the initial numbers generated are "less random" so will be discarded */
28#define RNG_WARMUP_COUNT 0x40000
29
30#define RNG_INT_OFF 0x1
31
32static void __init nsp_rng_init(void __iomem *base)
33{
34 u32 val;
35
36 /* mask the interrupt */
37 val = readl(base + RNG_INT_MASK);
38 val |= RNG_INT_OFF;
39 writel(val, base + RNG_INT_MASK);
40}
41
42static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
43 bool wait)
44{
45 void __iomem *rng_base = (void __iomem *)rng->priv;
46 u32 max_words = max / sizeof(u32);
47 u32 num_words, count;
48
49 while ((__raw_readl(rng_base + RNG_STATUS) >> 24) == 0) {
50 if (!wait)
51 return 0;
52 cpu_relax();
53 }
54
55 num_words = readl(rng_base + RNG_STATUS) >> 24;
56 if (num_words > max_words)
57 num_words = max_words;
58
59 for (count = 0; count < num_words; count++)
60 ((u32 *)buf)[count] = readl(rng_base + RNG_DATA);
61
62 return num_words * sizeof(u32);
63}
64
65static struct hwrng bcm2835_rng_ops = {
66 .name = "bcm2835",
67 .read = bcm2835_rng_read,
68};
69
70static const struct of_device_id bcm2835_rng_of_match[] = {
71 { .compatible = "brcm,bcm2835-rng"},
72 { .compatible = "brcm,bcm-nsp-rng", .data = nsp_rng_init},
73 { .compatible = "brcm,bcm5301x-rng", .data = nsp_rng_init},
74 {},
75};
76
77static int bcm2835_rng_probe(struct platform_device *pdev)
78{
79 struct device *dev = &pdev->dev;
80 struct device_node *np = dev->of_node;
81 void (*rng_setup)(void __iomem *base);
82 const struct of_device_id *rng_id;
83 void __iomem *rng_base;
84 int err;
85
86 /* map peripheral */
87 rng_base = of_iomap(np, 0);
88 if (!rng_base) {
89 dev_err(dev, "failed to remap rng regs");
90 return -ENODEV;
91 }
92 bcm2835_rng_ops.priv = (unsigned long)rng_base;
93
94 rng_id = of_match_node(bcm2835_rng_of_match, np);
95 if (!rng_id) {
96 iounmap(rng_base);
97 return -EINVAL;
98 }
99 /* Check for rng init function, execute it */
100 rng_setup = rng_id->data;
101 if (rng_setup)
102 rng_setup(rng_base);
103
104 /* set warm-up count & enable */
105 __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
106 __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
107
108 /* register driver */
109 err = hwrng_register(&bcm2835_rng_ops);
110 if (err) {
111 dev_err(dev, "hwrng registration failed\n");
112 iounmap(rng_base);
113 } else
114 dev_info(dev, "hwrng registered\n");
115
116 return err;
117}
118
119static int bcm2835_rng_remove(struct platform_device *pdev)
120{
121 void __iomem *rng_base = (void __iomem *)bcm2835_rng_ops.priv;
122
123 /* disable rng hardware */
124 __raw_writel(0, rng_base + RNG_CTRL);
125
126 /* unregister driver */
127 hwrng_unregister(&bcm2835_rng_ops);
128 iounmap(rng_base);
129
130 return 0;
131}
132
133MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match);
134
135static struct platform_driver bcm2835_rng_driver = {
136 .driver = {
137 .name = "bcm2835-rng",
138 .of_match_table = bcm2835_rng_of_match,
139 },
140 .probe = bcm2835_rng_probe,
141 .remove = bcm2835_rng_remove,
142};
143module_platform_driver(bcm2835_rng_driver);
144
145MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
146MODULE_DESCRIPTION("BCM2835 Random Number Generator (RNG) driver");
147MODULE_LICENSE("GPL v2");