Add some structs for files that DSi_NAND reads (#1842)

* Add DSiFirmwareSystemSettings

* Replace DSiFirmwareSystemSettings::TouchCalibration fields with std::arrays

- So assignment can be done in one line

* Make DSiFirmwareSystemSettings a union

- So its bytes can be accessed

* Add a comment

* Use DSiFirmwareSystemSettings instead of raw byte offsets

* Add definitions for DSiSerialData and DSiHardwareInfoN

* Move DSiFirmwareSystemSettings's hash update logic into its own method

src/DSi_NAND.h

@@ -22,6 +22,8 @@
 #include "types.h"
 #include "NDS_Header.h"
 #include "DSi_TMD.h"
+#include "SPI_Firmware.h"
+#include <array>
 #include <vector>
 #include <string>
 
@@ -35,6 +37,10 @@ enum
     TitleData_BannerSav,
 };
 
+union DSiFirmwareSystemSettings;
+union DSiSerialData;
+using DSiHardwareInfoN = std::array<u8, 0x9C>;
+
 bool Init(u8* es_keyY);
 void DeInit();
 
@@ -42,9 +48,9 @@ Platform::FileHandle* GetFile();
 
 void GetIDs(u8* emmc_cid, u64& consoleid);
 
-void ReadHardwareInfo(u8* dataS, u8* dataN);
+void ReadHardwareInfo(DSiSerialData& dataS, DSiHardwareInfoN& dataN);
 
-void ReadUserData(u8* data);
+void ReadUserData(DSiFirmwareSystemSettings& data);
 void PatchUserData();
 
 void ListTitles(u32 category, std::vector<u32>& titlelist);
@@ -58,6 +64,108 @@ u32 GetTitleDataMask(u32 category, u32 titleid);
 bool ImportTitleData(u32 category, u32 titleid, int type, const char* file);
 bool ExportTitleData(u32 category, u32 titleid, int type, const char* file);
 
+typedef std::array<u8, 20> SHA1Hash;
+typedef std::array<u8, 8> TitleID;
+
+/// Firmware settings for the DSi, saved to the NAND as TWLCFG0.dat or TWLCFG1.dat.
+/// The DSi mirrors this information to its own firmware for compatibility with NDS games.
+/// @note The file is normally 16KiB, but only the first 432 bytes are used;
+/// the rest is FF-padded.
+/// This struct excludes the padding.
+/// @see https://problemkaputt.de/gbatek.htm#dsisdmmcfirmwaresystemsettingsdatafiles
+union DSiFirmwareSystemSettings
+{
+    struct
+    {
+        SHA1Hash Hash;
+        u8 Zero00[108];
+        u8 Version;
+        u8 UpdateCounter;
+        u8 Zero01[2];
+        u32 BelowRAMAreaSize;
+        u32 ConfigFlags;
+        u8 Zero02;
+        u8 CountryCode;
+        SPI_Firmware::Language Language;
+        u8 RTCYear;
+        u32 RTCOffset;
+        u8 Zero3[4];
+        u8 EULAVersion;
+        u8 Zero04[9];
+        u8 AlarmHour;
+        u8 AlarmMinute;
+        u8 Zero05[2];
+        bool AlarmEnable;
+        u8 Zero06[2];
+        u8 SystemMenuUsedTitleSlots;
+        u8 SystemMenuFreeTitleSlots;
+        u8 Unknown0;
+        u8 Unknown1;
+        u8 Zero07[3];
+        TitleID SystemMenuMostRecentTitleID;
+        std::array<u16, 2> TouchCalibrationADC1;
+        std::array<u8, 2> TouchCalibrationPixel1;
+        std::array<u16, 2> TouchCalibrationADC2;
+        std::array<u8, 2> TouchCalibrationPixel2;
+        u8 Unknown2[4];
+        u8 Zero08[4];
+        u8 FavoriteColor;
+        u8 Zero09;
+        u8 BirthdayMonth;
+        u8 BirthdayDay;
+        char16_t Nickname[11];
+        char16_t Message[27];
+        u8 ParentalControlsFlags;
+        u8 Zero10[6];
+        u8 ParentalControlsRegion;
+        u8 ParentalControlsYearsOfAgeRating;
+        u8 ParentalControlsSecretQuestion;
+        u8 Unknown3;
+        u8 Zero11[2];
+        char ParentalControlsPIN[5];
+        char16_t ParentalControlsSecretAnswer[65];
+    };
+    u8 Bytes[432];
+
+    void UpdateHash();
+};
+
+static_assert(sizeof(DSiFirmwareSystemSettings) == 432, "DSiFirmwareSystemSettings must be exactly 432 bytes");
+
+enum class ConsoleRegion : u8
+{
+    Japan,
+    USA,
+    Europe,
+    Australia,
+    China,
+    Korea,
+};
+
+/// Data file saved to 0:/sys/HWINFO_S.dat.
+/// @note The file is normally 16KiB, but only the first 164 bytes are used;
+/// the rest is FF-padded.
+/// This struct excludes the padding.
+/// @see https://problemkaputt.de/gbatek.htm#dsisdmmcfirmwaremiscfiles
+union DSiSerialData
+{
+    struct
+    {
+        u8 RsaSha1HMAC[0x80];
+        u32 Version;
+        u32 EntrySize;
+        u32 SupportedLanguages;
+        u8 Unknown0[4];
+        ConsoleRegion Region;
+        char Serial[12];
+        u8 Unknown1[3];
+        u8 TitleIDLSBs[4];
+    };
+    u8 Bytes[164];
+};
+
+static_assert(sizeof(DSiSerialData) == 164, "DSiSerialData must be exactly 164 bytes");
+
 }
 
 #endif // DSI_NAND_H