1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Generic PowerPC 44x RNG driver |
4 | * |
5 | * Copyright 2011 IBM Corporation |
6 | */ |
7 | |
8 | #include <linux/module.h> |
9 | #include <linux/kernel.h> |
10 | #include <linux/interrupt.h> |
11 | #include <linux/platform_device.h> |
12 | #include <linux/hw_random.h> |
13 | #include <linux/delay.h> |
14 | #include <linux/of_address.h> |
15 | #include <linux/of_platform.h> |
16 | #include <linux/io.h> |
17 | |
18 | #include "crypto4xx_core.h" |
19 | #include "crypto4xx_trng.h" |
20 | #include "crypto4xx_reg_def.h" |
21 | |
22 | #define PPC4XX_TRNG_CTRL 0x0008 |
23 | #define PPC4XX_TRNG_CTRL_DALM 0x20 |
24 | #define PPC4XX_TRNG_STAT 0x0004 |
25 | #define PPC4XX_TRNG_STAT_B 0x1 |
26 | #define PPC4XX_TRNG_DATA 0x0000 |
27 | |
28 | static int ppc4xx_trng_data_present(struct hwrng *rng, int wait) |
29 | { |
30 | struct crypto4xx_device *dev = (void *)rng->priv; |
31 | int busy, i, present = 0; |
32 | |
33 | for (i = 0; i < 20; i++) { |
34 | busy = (in_le32(dev->trng_base + PPC4XX_TRNG_STAT) & |
35 | PPC4XX_TRNG_STAT_B); |
36 | if (!busy || !wait) { |
37 | present = 1; |
38 | break; |
39 | } |
40 | udelay(10); |
41 | } |
42 | return present; |
43 | } |
44 | |
45 | static int ppc4xx_trng_data_read(struct hwrng *rng, u32 *data) |
46 | { |
47 | struct crypto4xx_device *dev = (void *)rng->priv; |
48 | *data = in_le32(dev->trng_base + PPC4XX_TRNG_DATA); |
49 | return 4; |
50 | } |
51 | |
52 | static void ppc4xx_trng_enable(struct crypto4xx_device *dev, bool enable) |
53 | { |
54 | u32 device_ctrl; |
55 | |
56 | device_ctrl = readl(addr: dev->ce_base + CRYPTO4XX_DEVICE_CTRL); |
57 | if (enable) |
58 | device_ctrl |= PPC4XX_TRNG_EN; |
59 | else |
60 | device_ctrl &= ~PPC4XX_TRNG_EN; |
61 | writel(val: device_ctrl, addr: dev->ce_base + CRYPTO4XX_DEVICE_CTRL); |
62 | } |
63 | |
64 | static const struct of_device_id ppc4xx_trng_match[] = { |
65 | { .compatible = "ppc4xx-rng" , }, |
66 | { .compatible = "amcc,ppc460ex-rng" , }, |
67 | { .compatible = "amcc,ppc440epx-rng" , }, |
68 | {}, |
69 | }; |
70 | |
71 | void ppc4xx_trng_probe(struct crypto4xx_core_device *core_dev) |
72 | { |
73 | struct crypto4xx_device *dev = core_dev->dev; |
74 | struct device_node *trng = NULL; |
75 | struct hwrng *rng = NULL; |
76 | int err; |
77 | |
78 | /* Find the TRNG device node and map it */ |
79 | trng = of_find_matching_node(NULL, matches: ppc4xx_trng_match); |
80 | if (!trng || !of_device_is_available(device: trng)) { |
81 | of_node_put(node: trng); |
82 | return; |
83 | } |
84 | |
85 | dev->trng_base = of_iomap(node: trng, index: 0); |
86 | of_node_put(node: trng); |
87 | if (!dev->trng_base) |
88 | goto err_out; |
89 | |
90 | rng = kzalloc(size: sizeof(*rng), GFP_KERNEL); |
91 | if (!rng) |
92 | goto err_out; |
93 | |
94 | rng->name = KBUILD_MODNAME; |
95 | rng->data_present = ppc4xx_trng_data_present; |
96 | rng->data_read = ppc4xx_trng_data_read; |
97 | rng->priv = (unsigned long) dev; |
98 | core_dev->trng = rng; |
99 | ppc4xx_trng_enable(dev, enable: true); |
100 | out_le32(dev->trng_base + PPC4XX_TRNG_CTRL, PPC4XX_TRNG_CTRL_DALM); |
101 | err = devm_hwrng_register(dev: core_dev->device, rng: core_dev->trng); |
102 | if (err) { |
103 | ppc4xx_trng_enable(dev, enable: false); |
104 | dev_err(core_dev->device, "failed to register hwrng (%d).\n" , |
105 | err); |
106 | goto err_out; |
107 | } |
108 | return; |
109 | |
110 | err_out: |
111 | iounmap(addr: dev->trng_base); |
112 | kfree(objp: rng); |
113 | dev->trng_base = NULL; |
114 | core_dev->trng = NULL; |
115 | } |
116 | |
117 | void ppc4xx_trng_remove(struct crypto4xx_core_device *core_dev) |
118 | { |
119 | if (core_dev && core_dev->trng) { |
120 | struct crypto4xx_device *dev = core_dev->dev; |
121 | |
122 | devm_hwrng_unregister(dve: core_dev->device, rng: core_dev->trng); |
123 | ppc4xx_trng_enable(dev, enable: false); |
124 | iounmap(addr: dev->trng_base); |
125 | kfree(objp: core_dev->trng); |
126 | } |
127 | } |
128 | |
129 | MODULE_ALIAS("ppc4xx_rng" ); |
130 | |