drivers/nvmem/nintendo-otp.c

   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
  29 struct nintendo_otp_priv {
  30         void __iomem *regs;
  31 };
  32
  33 struct nintendo_otp_devtype_data {
  34         const char *name;
  35         unsigned int num_banks;
  36 };
  37
  38 static const struct nintendo_otp_devtype_data hollywood_otp_data = {
  39         .name = "wii-otp",
  40         .num_banks = 1,
  41 };
  42
  43 static const struct nintendo_otp_devtype_data latte_otp_data = {
  44         .name = "wiiu-otp",
  45         .num_banks = 8,
  46 };
  47
  48 static 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
  67 static 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 };
  72 MODULE_DEVICE_TABLE(of, nintendo_otp_of_table);
  73
  74 static 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
 112 static 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 };
 119 module_platform_driver(nintendo_otp_driver);
 120 MODULE_AUTHOR("Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>");
 121 MODULE_DESCRIPTION("Nintendo Wii and Wii U OTP driver");
 122 MODULE_LICENSE("GPL v2");