boot: add battery calibration accessors.

stratosphere/boot/source/boot_calibration.cpp

@@ -0,0 +1,114 @@
+/*
+ * 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_functions.hpp"
+
+static constexpr size_t BatteryLotOffset = 0x2CE0;
+static constexpr size_t BatteryLotSize = 0x20;
+static constexpr size_t BatteryVersionOffset = 0x4310;
+static constexpr size_t BatteryVersionSize = 0x10;
+
+static constexpr u32 BisStorageId_Prodinfo = 27;
+
+static constexpr u32 DefaultBatteryVendor = static_cast<u32>('A');
+static constexpr u32 DefaultBatteryVersion = 0;
+
+static constexpr Result ResultCalInvalidCrc = 0xCAC6; /* TODO: Verify this really is cal, move to libstrat results. */
+
+u16 Boot::GetCrc16(const void *data, size_t size) {
+    static 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;
+}
+
+static Result ValidateCalibrationCrc16(const void *data, size_t size) {
+    const u8 *data_u8 = reinterpret_cast<const u8 *>(data);
+    if (Boot::GetCrc16(data, size - sizeof(u16)) != *(reinterpret_cast<const u16 *>(&data_u8[size - sizeof(u16)]))) {
+        return ResultCalInvalidCrc;
+    }
+    return ResultSuccess;
+}
+
+static Result GetBatteryVendorImpl(u32 *vendor) {
+    FsStorage s;
+    Result rc = fsOpenBisStorage(&s, BisStorageId_Prodinfo);
+    if (R_FAILED(rc)) {
+        return rc;
+    }
+    ON_SCOPE_EXIT { fsStorageClose(&s); };
+
+    u8 battery_lot[BatteryLotSize];
+    if (R_FAILED((rc = fsStorageRead(&s, BatteryLotOffset, battery_lot, sizeof(battery_lot))))) {
+        return rc;
+    }
+
+    if (R_FAILED((rc = ValidateCalibrationCrc16(battery_lot, sizeof(battery_lot))))) {
+        return rc;
+    }
+
+    *vendor = battery_lot[7];
+    return ResultSuccess;
+}
+
+static Result GetBatteryVersionImpl(u32 *version) {
+    FsStorage s;
+    Result rc = fsOpenBisStorage(&s, BisStorageId_Prodinfo);
+    if (R_FAILED(rc)) {
+        return rc;
+    }
+    ON_SCOPE_EXIT { fsStorageClose(&s); };
+
+    u8 battery_version[BatteryVersionSize];
+    if (R_FAILED((rc = fsStorageRead(&s, BatteryVersionOffset, battery_version, sizeof(battery_version))))) {
+        return rc;
+    }
+
+    if (R_FAILED((rc = ValidateCalibrationCrc16(battery_version, sizeof(battery_version))))) {
+        return rc;
+    }
+
+    *version = battery_version[0];
+    return ResultSuccess;
+}
+
+u32 Boot::GetBatteryVendor() {
+    u32 vendor;
+    if (R_FAILED(GetBatteryVendorImpl(&vendor))) {
+        return DefaultBatteryVendor;
+    }
+    return vendor;
+}
+
+u32 Boot::GetBatteryVersion() {
+    u32 version;
+    if (R_FAILED(GetBatteryVersionImpl(&version))) {
+        return DefaultBatteryVersion;
+    }
+    return version;
+}

stratosphere/boot/source/boot_functions.hpp

@@ -73,4 +73,9 @@ class Boot {
         static void InitializeDisplay();
         static void ShowDisplay(size_t x, size_t y, size_t width, size_t height, const u32 *img);
         static void FinalizeDisplay();
+
+        /* Calibration utilities. */
+        static u16 GetCrc16(const void *data, size_t size);
+        static u32 GetBatteryVersion();
+        static u32 GetBatteryVendor();
 };