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406346d2 ZY |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Ingenic True Random Number Generator driver | |
4 | * Copyright (c) 2019 漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com> | |
5 | * Copyright (c) 2020 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com> | |
6 | */ | |
7 | ||
8 | #include <linux/clk.h> | |
9 | #include <linux/err.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/hw_random.h> | |
12 | #include <linux/io.h> | |
13 | #include <linux/iopoll.h> | |
0788257a | 14 | #include <linux/mod_devicetable.h> |
406346d2 | 15 | #include <linux/module.h> |
406346d2 ZY |
16 | #include <linux/platform_device.h> |
17 | #include <linux/slab.h> | |
18 | ||
19 | /* DTRNG register offsets */ | |
20 | #define TRNG_REG_CFG_OFFSET 0x00 | |
21 | #define TRNG_REG_RANDOMNUM_OFFSET 0x04 | |
22 | #define TRNG_REG_STATUS_OFFSET 0x08 | |
23 | ||
24 | /* bits within the CFG register */ | |
406346d2 ZY |
25 | #define CFG_GEN_EN BIT(0) |
26 | ||
27 | /* bits within the STATUS register */ | |
28 | #define STATUS_RANDOM_RDY BIT(0) | |
29 | ||
30 | struct ingenic_trng { | |
31 | void __iomem *base; | |
406346d2 ZY |
32 | struct hwrng rng; |
33 | }; | |
34 | ||
35 | static int ingenic_trng_init(struct hwrng *rng) | |
36 | { | |
37 | struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); | |
38 | unsigned int ctrl; | |
39 | ||
40 | ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); | |
41 | ctrl |= CFG_GEN_EN; | |
42 | writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); | |
43 | ||
44 | return 0; | |
45 | } | |
46 | ||
47 | static void ingenic_trng_cleanup(struct hwrng *rng) | |
48 | { | |
49 | struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); | |
50 | unsigned int ctrl; | |
51 | ||
52 | ctrl = readl(trng->base + TRNG_REG_CFG_OFFSET); | |
53 | ctrl &= ~CFG_GEN_EN; | |
54 | writel(ctrl, trng->base + TRNG_REG_CFG_OFFSET); | |
55 | } | |
56 | ||
57 | static int ingenic_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait) | |
58 | { | |
59 | struct ingenic_trng *trng = container_of(rng, struct ingenic_trng, rng); | |
60 | u32 *data = buf; | |
61 | u32 status; | |
62 | int ret; | |
63 | ||
64 | ret = readl_poll_timeout(trng->base + TRNG_REG_STATUS_OFFSET, status, | |
65 | status & STATUS_RANDOM_RDY, 10, 1000); | |
66 | if (ret == -ETIMEDOUT) { | |
67 | pr_err("%s: Wait for DTRNG data ready timeout\n", __func__); | |
68 | return ret; | |
69 | } | |
70 | ||
71 | *data = readl(trng->base + TRNG_REG_RANDOMNUM_OFFSET); | |
72 | ||
73 | return 4; | |
74 | } | |
75 | ||
76 | static int ingenic_trng_probe(struct platform_device *pdev) | |
77 | { | |
78 | struct ingenic_trng *trng; | |
e4ab6e72 | 79 | struct clk *clk; |
406346d2 ZY |
80 | int ret; |
81 | ||
82 | trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL); | |
83 | if (!trng) | |
84 | return -ENOMEM; | |
85 | ||
86 | trng->base = devm_platform_ioremap_resource(pdev, 0); | |
6257490b MK |
87 | if (IS_ERR(trng->base)) |
88 | return dev_err_probe(&pdev->dev, PTR_ERR(trng->base), | |
89 | "%s: Failed to map DTRNG registers\n", __func__); | |
406346d2 | 90 | |
e4ab6e72 | 91 | clk = devm_clk_get_enabled(&pdev->dev, NULL); |
6257490b MK |
92 | if (IS_ERR(clk)) |
93 | return dev_err_probe(&pdev->dev, PTR_ERR(clk), | |
94 | "%s: Cannot get and enable DTRNG clock\n", __func__); | |
406346d2 ZY |
95 | |
96 | trng->rng.name = pdev->name; | |
97 | trng->rng.init = ingenic_trng_init; | |
98 | trng->rng.cleanup = ingenic_trng_cleanup; | |
99 | trng->rng.read = ingenic_trng_read; | |
100 | ||
a40be5e8 | 101 | ret = devm_hwrng_register(&pdev->dev, &trng->rng); |
6257490b MK |
102 | if (ret) |
103 | return dev_err_probe(&pdev->dev, ret, "Failed to register hwrng\n"); | |
406346d2 ZY |
104 | |
105 | platform_set_drvdata(pdev, trng); | |
106 | ||
107 | dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n"); | |
108 | return 0; | |
109 | } | |
110 | ||
406346d2 ZY |
111 | static const struct of_device_id ingenic_trng_of_match[] = { |
112 | { .compatible = "ingenic,x1830-dtrng" }, | |
113 | { /* sentinel */ } | |
114 | }; | |
115 | MODULE_DEVICE_TABLE(of, ingenic_trng_of_match); | |
116 | ||
117 | static struct platform_driver ingenic_trng_driver = { | |
118 | .probe = ingenic_trng_probe, | |
406346d2 ZY |
119 | .driver = { |
120 | .name = "ingenic-trng", | |
121 | .of_match_table = ingenic_trng_of_match, | |
122 | }, | |
123 | }; | |
124 | ||
125 | module_platform_driver(ingenic_trng_driver); | |
126 | ||
127 | MODULE_LICENSE("GPL"); | |
128 | MODULE_AUTHOR("漆鹏振 (Qi Pengzhen) <aric.pzqi@ingenic.com>"); | |
129 | MODULE_AUTHOR("周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>"); | |
130 | MODULE_DESCRIPTION("Ingenic True Random Number Generator driver"); |