1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Nintendo Wii and Wii U OTP driver
4 *
5 * This is a driver exposing the OTP of a Nintendo Wii or Wii U console.
6 *
7 * This memory contains common and per-console keys, signatures and
8 * related data required to access peripherals.
9 *
10 * Based on reversed documentation from https://wiiubrew.org/wiki/Hardware/OTP
11 *
12 * Copyright (C) 2021 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
13 */
14
15#include <linux/device.h>
16#include <linux/io.h>
17#include <linux/module.h>
18#include <linux/mod_devicetable.h>
19#include <linux/nvmem-provider.h>
20#include <linux/of_device.h>
21#include <linux/platform_device.h>
22
23#define HW_OTPCMD  0
24#define HW_OTPDATA 4
25#define OTP_READ   0x80000000
26#define BANK_SIZE  128
27#define WORD_SIZE  4
28
29struct nintendo_otp_priv {
30	void __iomem *regs;
31};
32
33struct nintendo_otp_devtype_data {
34	const char *name;
35	unsigned int num_banks;
36};
37
38static const struct nintendo_otp_devtype_data hollywood_otp_data = {
39	.name = "wii-otp",
40	.num_banks = 1,
41};
42
43static const struct nintendo_otp_devtype_data latte_otp_data = {
44	.name = "wiiu-otp",
45	.num_banks = 8,
46};
47
48static int nintendo_otp_reg_read(void *context,
49				 unsigned int reg, void *_val, size_t bytes)
50{
51	struct nintendo_otp_priv *priv = context;
52	u32 *val = _val;
53	int words = bytes / WORD_SIZE;
54	u32 bank, addr;
55
56	while (words--) {
57		bank = (reg / BANK_SIZE) << 8;
58		addr = (reg / WORD_SIZE) % (BANK_SIZE / WORD_SIZE);
59		iowrite32be(OTP_READ | bank | addr, priv->regs + HW_OTPCMD);
60		*val++ = ioread32be(priv->regs + HW_OTPDATA);
61		reg += WORD_SIZE;
62	}
63
64	return 0;
65}
66
67static const struct of_device_id nintendo_otp_of_table[] = {
68	{ .compatible = "nintendo,hollywood-otp", .data = &hollywood_otp_data },
69	{ .compatible = "nintendo,latte-otp", .data = &latte_otp_data },
70	{/* sentinel */},
71};
72MODULE_DEVICE_TABLE(of, nintendo_otp_of_table);
73
74static int nintendo_otp_probe(struct platform_device *pdev)
75{
76	struct device *dev = &pdev->dev;
77	const struct of_device_id *of_id =
78		of_match_device(nintendo_otp_of_table, dev);
79	struct nvmem_device *nvmem;
80	struct nintendo_otp_priv *priv;
81
82	struct nvmem_config config = {
83		.stride = WORD_SIZE,
84		.word_size = WORD_SIZE,
85		.reg_read = nintendo_otp_reg_read,
86		.read_only = true,
87		.root_only = true,
88	};
89
90	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
91	if (!priv)
92		return -ENOMEM;
93
94	priv->regs = devm_platform_ioremap_resource(pdev, 0);
95	if (IS_ERR(priv->regs))
96		return PTR_ERR(priv->regs);
97
98	if (of_id->data) {
99		const struct nintendo_otp_devtype_data *data = of_id->data;
100		config.name = data->name;
101		config.size = data->num_banks * BANK_SIZE;
102	}
103
104	config.dev = dev;
105	config.priv = priv;
106
107	nvmem = devm_nvmem_register(dev, &config);
108
109	return PTR_ERR_OR_ZERO(nvmem);
110}
111
112static struct platform_driver nintendo_otp_driver = {
113	.probe = nintendo_otp_probe,
114	.driver = {
115		.name = "nintendo-otp",
116		.of_match_table = nintendo_otp_of_table,
117	},
118};
119module_platform_driver(nintendo_otp_driver);
120MODULE_AUTHOR("Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>");
121MODULE_DESCRIPTION("Nintendo Wii and Wii U OTP driver");
122MODULE_LICENSE("GPL v2");
123