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> |
14 | #include <linux/mod_devicetable.h> |
15 | #include <linux/module.h> |
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 */ |
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; |
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(addr: trng->base + TRNG_REG_CFG_OFFSET); |
41 | ctrl |= CFG_GEN_EN; |
42 | writel(val: ctrl, addr: 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(addr: trng->base + TRNG_REG_CFG_OFFSET); |
53 | ctrl &= ~CFG_GEN_EN; |
54 | writel(val: ctrl, addr: 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(addr: 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; |
79 | struct clk *clk; |
80 | int ret; |
81 | |
82 | trng = devm_kzalloc(dev: &pdev->dev, size: sizeof(*trng), GFP_KERNEL); |
83 | if (!trng) |
84 | return -ENOMEM; |
85 | |
86 | trng->base = devm_platform_ioremap_resource(pdev, index: 0); |
87 | if (IS_ERR(ptr: trng->base)) |
88 | return dev_err_probe(dev: &pdev->dev, err: PTR_ERR(ptr: trng->base), |
89 | fmt: "%s: Failed to map DTRNG registers\n" , __func__); |
90 | |
91 | clk = devm_clk_get_enabled(dev: &pdev->dev, NULL); |
92 | if (IS_ERR(ptr: clk)) |
93 | return dev_err_probe(dev: &pdev->dev, err: PTR_ERR(ptr: clk), |
94 | fmt: "%s: Cannot get and enable DTRNG clock\n" , __func__); |
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 | |
101 | ret = devm_hwrng_register(dev: &pdev->dev, rng: &trng->rng); |
102 | if (ret) |
103 | return dev_err_probe(dev: &pdev->dev, err: ret, fmt: "Failed to register hwrng\n" ); |
104 | |
105 | platform_set_drvdata(pdev, data: trng); |
106 | |
107 | dev_info(&pdev->dev, "Ingenic DTRNG driver registered\n" ); |
108 | return 0; |
109 | } |
110 | |
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, |
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" ); |
131 | |