Atmosphere/stratosphere/boot/source/boot_calibration.cpp

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/*
* Copyright (c) 2018-2019 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "boot_calibration.hpp"
namespace sts::boot {
namespace {
/* Convenience definitions. */
constexpr size_t BatteryLotOffset = 0x2CE0;
constexpr size_t BatteryLotSize = 0x20;
constexpr size_t BatteryVersionOffset = 0x4310;
constexpr size_t BatteryVersionSize = 0x10;
constexpr u32 DefaultBatteryVendor = static_cast<u32>('A');
constexpr u32 DefaultBatteryVersion = 0;
constexpr Result ResultCalInvalidCrc = 0xCAC6; /* TODO: Verify this really is cal, move to libstrat results. */
/* Helpers. */
constexpr u16 GetCrc16(const void *data, size_t size) {
constexpr u16 s_crc_table[0x10] = {
0x0000, 0xCC01, 0xD801, 0x1400, 0xF001, 0x3C00, 0x2800, 0xE401,
0xA001, 0x6C00, 0x7800, 0xB401, 0x5000, 0x9C01, 0x8801, 0x4400
};
if (data == nullptr) {
std::abort();
}
u16 crc16 = 0x55AA;
const u8 *data_u8 = reinterpret_cast<const u8 *>(data);
for (size_t i = 0; i < size; i++) {
crc16 = (crc16 >> 4) ^ (s_crc_table[crc16 & 0xF]) ^ (s_crc_table[data_u8[i] & 0xF]);
crc16 = (crc16 >> 4) ^ (s_crc_table[crc16 & 0xF]) ^ (s_crc_table[(data_u8[i] >> 4) & 0xF]);
}
return crc16;
}
Result ValidateCalibrationCrc16(const void *data, size_t size) {
const u8 *data_u8 = reinterpret_cast<const u8 *>(data);
if (GetCrc16(data, size - sizeof(u16)) != *(reinterpret_cast<const u16 *>(&data_u8[size - sizeof(u16)]))) {
return ResultCalInvalidCrc;
}
return ResultSuccess;
}
Result GetBatteryVendorImpl(u32 *vendor) {
FsStorage s;
R_TRY(fsOpenBisStorage(&s, FsBisStorageId_CalibrationBinary));
ON_SCOPE_EXIT { fsStorageClose(&s); };
u8 battery_lot[BatteryLotSize];
R_TRY(fsStorageRead(&s, BatteryLotOffset, battery_lot, sizeof(battery_lot)));
R_TRY(ValidateCalibrationCrc16(battery_lot, sizeof(battery_lot)));
*vendor = battery_lot[7];
return ResultSuccess;
}
Result GetBatteryVersionImpl(u32 *version) {
FsStorage s;
R_TRY(fsOpenBisStorage(&s, FsBisStorageId_CalibrationBinary));
ON_SCOPE_EXIT { fsStorageClose(&s); };
u8 battery_version[BatteryVersionSize];
R_TRY(fsStorageRead(&s, BatteryVersionOffset, battery_version, sizeof(battery_version)));
R_TRY(ValidateCalibrationCrc16(battery_version, sizeof(battery_version)));
*version = battery_version[0];
return ResultSuccess;
}
}
u32 GetBatteryVendor() {
u32 vendor;
if (R_FAILED(GetBatteryVendorImpl(&vendor))) {
return DefaultBatteryVendor;
}
return vendor;
}
u32 GetBatteryVersion() {
u32 version;
if (R_FAILED(GetBatteryVersionImpl(&version))) {
return DefaultBatteryVersion;
}
return version;
}
}