Initial commit

examples/mass-storage/arm7/source/Arm7State.h

@@ -0,0 +1,8 @@
+#pragma once
+
+/// @brief Enum representing the arm7 state.
+enum class Arm7State
+{
+    Idle,
+    ExitRequested
+};

examples/mass-storage/arm7/source/ExitMode.h

@@ -0,0 +1,10 @@
+#pragma once
+
+/// @brief Enum representing the exit mode of launcher.
+enum class ExitMode
+{
+    /// @brief Reset the system (DSi mode only).
+    Reset,
+    /// @brief Power off the system.
+    PowerOff
+};

examples/mass-storage/arm7/source/common.h

@@ -0,0 +1,5 @@
+#pragma once
+#include <nds.h>
+#include <libtwl/rtos/rtosMutex.h>
+
+extern rtos_mutex_t gCardMutex;

examples/mass-storage/arm7/source/dldi.s

@@ -0,0 +1,16 @@
+.global _dldi_start
+.equ _dldi_start,					0x037F8000
+.global _io_dldi
+.equ _io_dldi,						(_dldi_start + 0x60)
+.global _DLDI_startup_ptr
+.equ _DLDI_startup_ptr,				(_io_dldi + 0x8)
+.global _DLDI_isInserted_ptr
+.equ _DLDI_isInserted_ptr,			(_io_dldi + 0xC)
+.global _DLDI_readSectors_ptr
+.equ _DLDI_readSectors_ptr,			(_io_dldi + 0x10)
+.global _DLDI_writeSectors_ptr
+.equ _DLDI_writeSectors_ptr,		(_io_dldi + 0x14)
+.global _DLDI_clearStatus_ptr
+.equ _DLDI_clearStatus_ptr,			(_io_dldi + 0x18)
+.global _DLDI_shutdown_ptr
+.equ _DLDI_shutdown_ptr,			(_io_dldi + 0x1C)

examples/mass-storage/arm7/source/ipcServices/DldiIpcService.cpp

@@ -0,0 +1,53 @@
+#include "common.h"
+#include <string.h>
+#include <nds/disc_io.h>
+#include "DldiIpcService.h"
+
+extern FN_MEDIUM_STARTUP _DLDI_startup_ptr;
+extern FN_MEDIUM_READSECTORS _DLDI_readSectors_ptr;
+extern FN_MEDIUM_WRITESECTORS _DLDI_writeSectors_ptr;
+
+void DldiIpcService::HandleMessage(u32 data)
+{
+    auto cmd = reinterpret_cast<const dldi_ipc_cmd_t*>(data << 2);
+    switch (cmd->cmd)
+    {
+        case DLDI_IPC_CMD_SETUP:
+            SetupDldi(cmd);
+            break;
+
+        case DLDI_IPC_CMD_READ_SECTORS:
+            ReadSectors(cmd);
+            break;
+
+        case DLDI_IPC_CMD_WRITE_SECTORS:
+            WriteSectors(cmd);
+            break;
+    }
+}
+
+void DldiIpcService::SetupDldi(const dldi_ipc_cmd_t* cmd) const
+{
+    memcpy((void*)0x037F8000, cmd->buffer, 16 * 1024);
+    bool result;
+    rtos_lockMutex(&gCardMutex);
+    result = _DLDI_startup_ptr();
+    rtos_unlockMutex(&gCardMutex);
+    SendResponseMessage(result);
+}
+
+void DldiIpcService::ReadSectors(const dldi_ipc_cmd_t* cmd) const
+{
+    rtos_lockMutex(&gCardMutex);
+    _DLDI_readSectors_ptr(cmd->sector, cmd->count, cmd->buffer);
+    rtos_unlockMutex(&gCardMutex);
+    SendResponseMessage(0);
+}
+
+void DldiIpcService::WriteSectors(const dldi_ipc_cmd_t* cmd) const
+{
+    rtos_lockMutex(&gCardMutex);
+    _DLDI_writeSectors_ptr(cmd->sector, cmd->count, cmd->buffer);
+    rtos_unlockMutex(&gCardMutex);
+    SendResponseMessage(0);
+}

examples/mass-storage/arm7/source/ipcServices/DldiIpcService.h

@@ -0,0 +1,19 @@
+#pragma once
+#include "ipc/ThreadIpcService.h"
+#include "dldiIpcCommand.h"
+#include "ipcChannels.h"
+
+class DldiIpcService : public ThreadIpcService
+{
+    u32 _threadStack[128];
+
+    void SetupDldi(const dldi_ipc_cmd_t* cmd) const;
+    void ReadSectors(const dldi_ipc_cmd_t* cmd) const;
+    void WriteSectors(const dldi_ipc_cmd_t* cmd) const;
+
+public:
+    DldiIpcService()
+        : ThreadIpcService(IPC_CHANNEL_DLDI, 6, _threadStack, sizeof(_threadStack)) { }
+
+    void HandleMessage(u32 data) override;
+};

examples/mass-storage/arm7/source/main.cpp

@@ -0,0 +1,388 @@
+#include "common.h"
+#include <nds/disc_io.h>
+#include <libtwl/rtos/rtosIrq.h>
+#include <libtwl/rtos/rtosThread.h>
+#include <libtwl/rtos/rtosEvent.h>
+#include <libtwl/sound/soundChannel.h>
+#include <libtwl/timer/timer.h>
+#include <libtwl/sound/sound.h>
+#include <libtwl/ipc/ipcSync.h>
+#include <libtwl/ipc/ipcFifoSystem.h>
+#include <libtwl/sys/sysPower.h>
+#include <libtwl/sio/sioRtc.h>
+#include <libtwl/sio/sio.h>
+#include <libtwl/gfx/gfxStatus.h>
+#include <libtwl/mem/memSwap.h>
+#include <libtwl/i2c/i2cMcu.h>
+#include <libtwl/spi/spiPmic.h>
+#include "ipcServices/DldiIpcService.h"
+#include "ExitMode.h"
+#include "Arm7State.h"
+#include "tusb.h"
+#include "usb_descriptors.h"
+
+static DldiIpcService sDldiIpcService;
+
+rtos_mutex_t gCardMutex;
+
+static rtos_event_t sVBlankEvent;
+static ExitMode sExitMode;
+static Arm7State sState;
+static volatile u8 sMcuIrqFlag = false;
+
+static u32 sSdBlockCount;
+static u8 sSector0Buffer[512] alignas(4);
+
+static rtos_thread_t sUsbThread;
+static u32 sUsbThreadStack[512];
+
+extern FN_MEDIUM_READSECTORS _DLDI_readSectors_ptr;
+extern FN_MEDIUM_WRITESECTORS _DLDI_writeSectors_ptr;
+
+static void vblankIrq(u32 irqMask)
+{
+    rtos_signalEvent(&sVBlankEvent);
+}
+
+static void mcuIrq(u32 irq2Mask)
+{
+    sMcuIrqFlag = true;
+}
+
+static void checkMcuIrq(void)
+{
+    // mcu only exists in DSi mode
+    if (isDSiMode())
+    {
+        // check and ack the flag atomically
+        if (mem_swapByte(false, &sMcuIrqFlag))
+        {
+            // check the irq mask
+            u32 irqMask = mcu_getIrqMask();
+            if (irqMask & MCU_IRQ_RESET)
+            {
+                // power button was released
+                sExitMode = ExitMode::Reset;
+                sState = Arm7State::ExitRequested;
+            }
+            else if (irqMask & MCU_IRQ_POWER_OFF)
+            {
+                // power button was held long to trigger a power off
+                sExitMode = ExitMode::PowerOff;
+                sState = Arm7State::ExitRequested;
+            }
+        }
+    }
+}
+
+static void initializeVBlankIrq()
+{
+    rtos_createEvent(&sVBlankEvent);
+    rtos_setIrqFunc(RTOS_IRQ_VBLANK, vblankIrq);
+    rtos_enableIrqMask(RTOS_IRQ_VBLANK);
+    gfx_setVBlankIrqEnabled(true);
+}
+
+static void usbThreadMain(void* arg)
+{
+    while (true)
+    {
+        tud_task();
+    }
+}
+
+// Based on https://github.com/asiekierka/nrio-usb-disk/blob/main/source/msc.c msc_find_block_count by Asie
+// Note: This might not work correctly in some cases. It would be better if the DSpico would expose the actual SD capacity.
+static u32 findSdCardBlockCount()
+{
+    rtos_lockMutex(&gCardMutex);
+    _DLDI_readSectors_ptr(0, 1, sSector0Buffer);
+    rtos_unlockMutex(&gCardMutex);
+
+    u16 footer = *(u16*)(sSector0Buffer + 510);
+    if (footer == 0xAA55)
+    {
+        u8 bootOpcode = sSector0Buffer[0];
+        if (bootOpcode == 0xEB || bootOpcode == 0xE9 || bootOpcode == 0xE8)
+        {
+            if (!memcmp(sSector0Buffer + 54, "FAT", 3) || !memcmp(sSector0Buffer + 82, "FAT32   ", 8))
+            {
+                u32 totalSectors = *(u32*)(sSector0Buffer + 32);
+                if (totalSectors < 0x10000)
+                {
+                    totalSectors = sSector0Buffer[19] | (sSector0Buffer[20] << 8);
+                }
+                return totalSectors;
+            }
+        }
+
+        u32 blockCount = 0;
+        for (u32 tableEntry = 0x1BE; tableEntry < 0x1FE; tableEntry += 16)
+        {
+            u32 pStart = *(u16*)(sSector0Buffer + tableEntry + 8) | (*(u16*)(sSector0Buffer + tableEntry + 10) << 16);
+            u32 pCount = *(u16*)(sSector0Buffer + tableEntry + 12) | (*(u16*)(sSector0Buffer + tableEntry + 14) << 16);
+            u32 pEnd = pStart + pCount;
+            if (pEnd > blockCount)
+            {
+                blockCount = pEnd;
+            }
+        }
+
+        return blockCount;
+    }
+
+    return 0;
+}
+
+static void initializeArm7()
+{
+    rtos_initIrq();
+    rtos_startMainThread();
+    ipc_initFifoSystem();
+
+    rtos_createMutex(&gCardMutex);
+
+    // clear sound registers
+    dmaFillWords(0, (void*)0x04000400, 0x100);
+
+    pmic_setAmplifierEnable(true);
+    sys_setSoundPower(true);
+
+    readUserSettings();
+    pmic_setPowerLedBlink(PMIC_CONTROL_POWER_LED_BLINK_NONE);
+
+    sio_setGpioSiIrq(false);
+    sio_setGpioMode(RCNT0_L_MODE_GPIO);
+
+    rtc_init();
+
+    sDldiIpcService.Start();
+
+    snd_setMasterVolume(127);
+    snd_setMasterEnable(true);
+
+    initializeVBlankIrq();
+
+    if (isDSiMode())
+    {
+        rtos_setIrq2Func(RTOS_IRQ2_MCU, mcuIrq);
+        rtos_enableIrq2Mask(RTOS_IRQ2_MCU);
+    }
+
+    ipc_setArm7SyncBits(7);
+
+    while (ipc_getArm9SyncBits() != 6)
+    {
+        rtos_waitEvent(&sVBlankEvent, true, true);
+    }
+
+    sSdBlockCount = findSdCardBlockCount();
+
+    tusb_rhport_init_t dev_init =
+    {
+        .role = TUSB_ROLE_DEVICE,
+        .speed = TUSB_SPEED_AUTO
+    };
+    tusb_init(0, &dev_init);
+
+    rtos_createThread(&sUsbThread, 3, usbThreadMain, NULL, sUsbThreadStack, sizeof(sUsbThreadStack));
+    rtos_wakeupThread(&sUsbThread);
+}
+
+static void updateArm7IdleState()
+{
+    checkMcuIrq();
+
+    if (sState == Arm7State::ExitRequested)
+    {
+        snd_setMasterVolume(0); // mute sound
+    }
+}
+
+static bool performExit(ExitMode exitMode)
+{
+    switch (exitMode)
+    {
+        case ExitMode::Reset:
+        {
+            mcu_setWarmBootFlag(true);
+            mcu_hardReset();
+            break;
+        }
+        case ExitMode::PowerOff:
+        {
+            pmic_shutdown();
+            break;
+        }
+    }
+
+    while (true); // wait infinitely for exit
+}
+
+static void updateArm7ExitRequestedState()
+{
+    performExit(sExitMode);
+}
+
+static void updateArm7()
+{
+    switch (sState)
+    {
+        case Arm7State::Idle:
+        {
+            updateArm7IdleState();
+            break;
+        }
+        case Arm7State::ExitRequested:
+        {
+            updateArm7ExitRequestedState();
+            break;
+        }
+    }
+}
+
+int main()
+{
+    sState = Arm7State::Idle;
+    initializeArm7();
+
+    while (true)
+    {
+        rtos_waitEvent(&sVBlankEvent, true, true);
+        updateArm7();
+    }
+
+    return 0;
+}
+
+// Invoked when received SCSI_CMD_INQUIRY
+// Application fill vendor id, product id and revision with string up to 8, 16, 4 characters respectively
+void tud_msc_inquiry_cb(uint8_t lun, uint8_t vendor_id[8], uint8_t product_id[16], uint8_t product_rev[4])
+{
+    (void) lun;
+
+    const char vid[] = "DSpico";
+    const char pid[] = "Mass Storage";
+    const char rev[] = "1.0";
+
+    memcpy(vendor_id  , vid, strlen(vid));
+    memcpy(product_id , pid, strlen(pid));
+    memcpy(product_rev, rev, strlen(rev));
+}
+
+// Invoked when received Test Unit Ready command.
+// return true allowing host to read/write this LUN e.g SD card inserted
+bool tud_msc_test_unit_ready_cb(uint8_t lun)
+{
+    (void) lun;
+    return true;
+}
+
+// Invoked when received SCSI_CMD_READ_CAPACITY_10 and SCSI_CMD_READ_FORMAT_CAPACITY to determine the disk size
+// Application update block count and block size
+void tud_msc_capacity_cb(uint8_t lun, uint32_t* block_count, uint16_t* block_size)
+{
+    (void) lun;
+
+    *block_count = sSdBlockCount;
+    *block_size  = 512;
+}
+
+// Invoked when received Start Stop Unit command
+// - Start = 0 : stopped power mode, if load_eject = 1 : unload disk storage
+// - Start = 1 : active mode, if load_eject = 1 : load disk storage
+bool tud_msc_start_stop_cb(uint8_t lun, uint8_t power_condition, bool start, bool load_eject)
+{
+    (void) lun;
+    (void) power_condition;
+    return true;
+}
+
+// Callback invoked when received READ10 command.
+// Copy disk's data to buffer (up to bufsize) and return number of copied bytes.
+int32_t tud_msc_read10_cb(uint8_t lun, uint32_t lba, uint32_t offset, void* buffer, uint32_t bufsize)
+{
+    (void) lun;
+
+    if (offset != 0 || (bufsize % 512) != 0)
+    {
+        return -1;
+    }
+
+    rtos_lockMutex(&gCardMutex);
+    _DLDI_readSectors_ptr(lba, bufsize / 512, buffer);
+    rtos_unlockMutex(&gCardMutex);
+
+    return (int32_t)bufsize;
+}
+
+bool tud_msc_is_writable_cb(uint8_t lun)
+{
+    (void) lun;
+    return true;
+}
+
+// Callback invoked when received WRITE10 command.
+// Process data in buffer to disk's storage and return number of written bytes
+int32_t tud_msc_write10_cb(uint8_t lun, uint32_t lba, uint32_t offset, uint8_t* buffer, uint32_t bufsize)
+{
+    (void) lun;
+
+    if (offset != 0 || (bufsize % 512) != 0)
+    {
+        return -1;
+    }
+
+    rtos_lockMutex(&gCardMutex);
+    _DLDI_writeSectors_ptr(lba, bufsize / 512, buffer);
+    rtos_unlockMutex(&gCardMutex);
+
+    return (int32_t)bufsize;
+}
+
+// Callback invoked when received an SCSI command not in built-in list below
+// - READ_CAPACITY10, READ_FORMAT_CAPACITY, INQUIRY, MODE_SENSE6, REQUEST_SENSE
+// - READ10 and WRITE10 has their own callbacks
+int32_t tud_msc_scsi_cb(uint8_t lun, uint8_t const scsi_cmd[16], void* buffer, uint16_t bufsize)
+{
+    // read10 & write10 has their own callback and MUST not be handled here
+
+    void const* response = NULL;
+    int32_t resplen = 0;
+
+    // most scsi handled is input
+    bool in_xfer = true;
+
+    switch (scsi_cmd[0])
+    {
+        default:
+        {
+            // Set Sense = Invalid Command Operation
+            tud_msc_set_sense(lun, SCSI_SENSE_ILLEGAL_REQUEST, 0x20, 0x00);
+
+            // negative means error -> tinyusb could stall and/or response with failed status
+            resplen = -1;
+            break;
+        }
+    }
+
+    // return resplen must not larger than bufsize
+    if (resplen > bufsize)
+    {
+        resplen = bufsize;
+    }
+
+    if (response && (resplen > 0))
+    {
+        if(in_xfer)
+        {
+            memcpy(buffer, response, (size_t)resplen);
+        }
+        else
+        {
+            // SCSI output
+        }
+    }
+
+    return (int32_t)resplen;
+}

examples/mass-storage/arm7/source/tusb_config.h

@@ -0,0 +1,112 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#ifndef _TUSB_CONFIG_H_
+#define _TUSB_CONFIG_H_
+
+#include "usb_descriptors.h"
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+//--------------------------------------------------------------------+
+// Board Specific Configuration
+//--------------------------------------------------------------------+
+
+// RHPort number used for device can be defined by board.mk, default to port 0
+#ifndef BOARD_TUD_RHPORT
+#define BOARD_TUD_RHPORT      0
+#endif
+
+// RHPort max operational speed can defined by board.mk
+#ifndef BOARD_TUD_MAX_SPEED
+#define BOARD_TUD_MAX_SPEED   OPT_MODE_DEFAULT_SPEED
+#endif
+
+//--------------------------------------------------------------------
+// COMMON CONFIGURATION
+//--------------------------------------------------------------------
+
+// defined by compiler flags for flexibility
+#ifndef CFG_TUSB_MCU
+#define CFG_TUSB_MCU          OPT_MCU_DSPICO
+#endif
+
+#define TUP_DCD_ENDPOINT_MAX    16
+
+#ifndef CFG_TUSB_OS
+#define CFG_TUSB_OS           OPT_OS_CUSTOM
+#endif
+
+#ifndef CFG_TUSB_DEBUG
+#define CFG_TUSB_DEBUG        0
+#endif
+
+// Enable Device stack
+#define CFG_TUD_ENABLED       1
+
+// Default is max speed that hardware controller could support with on-chip PHY
+#define CFG_TUD_MAX_SPEED     BOARD_TUD_MAX_SPEED
+
+/* USB DMA on some MCUs can only access a specific SRAM region with restriction on alignment.
+ * Tinyusb use follows macros to declare transferring memory so that they can be put
+ * into those specific section.
+ * e.g
+ * - CFG_TUSB_MEM SECTION : __attribute__ (( section(".usb_ram") ))
+ * - CFG_TUSB_MEM_ALIGN   : __attribute__ ((aligned(4)))
+ */
+#ifndef CFG_TUSB_MEM_SECTION
+#define CFG_TUSB_MEM_SECTION
+#endif
+
+#ifndef CFG_TUSB_MEM_ALIGN
+#define CFG_TUSB_MEM_ALIGN          __attribute__ ((aligned(4)))
+#endif
+
+//--------------------------------------------------------------------
+// DEVICE CONFIGURATION
+//--------------------------------------------------------------------
+
+#ifndef CFG_TUD_ENDPOINT0_SIZE
+#define CFG_TUD_ENDPOINT0_SIZE    64
+#endif
+
+//------------- CLASS -------------//
+#define CFG_TUD_CDC               0
+#define CFG_TUD_MSC               1
+#define CFG_TUD_HID               0
+#define CFG_TUD_MIDI              0
+#define CFG_TUD_AUDIO             0
+#define CFG_TUD_VENDOR            0
+
+// MSC Buffer size of Device Mass storage
+#define CFG_TUD_MSC_EP_BUFSIZE    8192
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif /* _TUSB_CONFIG_H_ */

examples/mass-storage/arm7/source/usb_descriptors.c

@@ -0,0 +1,198 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Ha Thach (tinyusb.org)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+// #include "bsp/board_api.h"
+#include "tusb.h"
+#include "usb_descriptors.h"
+
+/* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
+ * Same VID/PID with different interface e.g MSC (first), then CDC (later) will possibly cause system error on PC.
+ *
+ * Auto ProductID layout's Bitmap:
+ *   [MSB]     AUDIO | MIDI | HID | MSC | CDC          [LSB]
+ */
+#define _PID_MAP(itf, n)  ( (CFG_TUD_##itf) << (n) )
+#define USB_PID           (0x4000 | _PID_MAP(CDC, 0) | _PID_MAP(MSC, 1) | _PID_MAP(HID, 2) | \
+    _PID_MAP(MIDI, 3) | _PID_MAP(AUDIO, 4) | _PID_MAP(VENDOR, 5) )
+
+//--------------------------------------------------------------------+
+// Device Descriptors
+//--------------------------------------------------------------------+
+tusb_desc_device_t const desc_device =
+{
+    .bLength            = sizeof(tusb_desc_device_t),
+    .bDescriptorType    = TUSB_DESC_DEVICE,
+    .bcdUSB             = 0x0110,
+
+    // Use Interface Association Descriptor (IAD) for Audio
+    // As required by USB Specs IAD's subclass must be common class (2) and protocol must be IAD (1)
+    .bDeviceClass       = TUSB_CLASS_MISC,
+    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
+    .bDeviceProtocol    = MISC_PROTOCOL_IAD,
+    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
+
+    .idVendor           = 0xCafe,
+    .idProduct          = USB_PID,
+    .bcdDevice          = 0x0100,
+
+    .iManufacturer      = 0x01,
+    .iProduct           = 0x02,
+    .iSerialNumber      = 0x03,
+
+    .bNumConfigurations = 0x01
+};
+
+// Invoked when received GET DEVICE DESCRIPTOR
+// Application return pointer to descriptor
+uint8_t const * tud_descriptor_device_cb(void)
+{
+    return (uint8_t const *)&desc_device;
+}
+
+//--------------------------------------------------------------------+
+// Configuration Descriptor
+//--------------------------------------------------------------------+
+#define CONFIG_TOTAL_LEN    	(TUD_CONFIG_DESC_LEN + TUD_MSC_DESC_LEN)
+
+#define EPNUM_MSC_OUT     0x01
+#define EPNUM_MSC_IN      0x81
+
+uint8_t const desc_configuration[] =
+{
+    // Config number, interface count, string index, total length, attribute, power in mA
+    TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
+
+    // Interface number, string index, EP Out & EP In address, EP size
+    TUD_MSC_DESCRIPTOR(ITF_NUM_MSC, 4, EPNUM_MSC_OUT, EPNUM_MSC_IN, 64),
+
+};
+
+// Invoked when received GET CONFIGURATION DESCRIPTOR
+// Application return pointer to descriptor
+// Descriptor contents must exist long enough for transfer to complete
+uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
+{
+  (void)index; // for multiple configurations
+  return desc_configuration;
+}
+
+//--------------------------------------------------------------------+
+// String Descriptors
+//--------------------------------------------------------------------+
+
+// String Descriptor Index
+enum {
+  STRID_LANGID = 0,
+  STRID_MANUFACTURER,
+  STRID_PRODUCT,
+  STRID_SERIAL,
+};
+
+// array of pointer to string descriptors
+char const *string_desc_arr[] =
+{
+    (const char[]) { 0x09, 0x04 },  // 0: is supported language is English (0x0409)
+    "LNH",                      // 1: Manufacturer
+    "DSpico",              // 2: Product
+    NULL,                           // 3: Serials will use unique ID if possible
+    "DSpico MSC"             // 4: MSC Interface
+};
+
+static uint16_t _desc_str[32 + 1];
+
+// Get USB Serial number string from unique ID if available. Return number of character.
+// Input is string descriptor from index 1 (index 0 is type + len)
+static inline size_t board_usb_get_serial(uint16_t desc_str1[], size_t max_chars) {
+  uint8_t uid[16] TU_ATTR_ALIGNED(4);
+  size_t uid_len;
+
+  // TODO work with make, but not working with esp32s3 cmake
+  // if ( board_get_unique_id ) {
+    // uid_len = board_get_unique_id(uid, sizeof(uid));
+  // }else {
+    // fixed serial string is 01234567889ABCDEF
+    uint32_t* uid32 = (uint32_t*) (uintptr_t) uid;
+    uid32[0] = 0x67452301;
+    uid32[1] = 0xEFCDAB89;
+    uid_len = 8;
+  // }
+
+  if ( uid_len > max_chars / 2 ) uid_len = max_chars / 2;
+
+  for ( size_t i = 0; i < uid_len; i++ ) {
+    for ( size_t j = 0; j < 2; j++ ) {
+      const char nibble_to_hex[16] = {
+          '0', '1', '2', '3', '4', '5', '6', '7',
+          '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+      };
+      uint8_t const nibble = (uid[i] >> (j * 4)) & 0xf;
+      desc_str1[i * 2 + (1 - j)] = nibble_to_hex[nibble]; // UTF-16-LE
+    }
+  }
+
+  return 2 * uid_len;
+}
+
+// Invoked when received GET STRING DESCRIPTOR request
+// Application return pointer to descriptor, whose contents must exist long enough for transfer to complete
+uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
+  (void) langid;
+  size_t chr_count;
+
+  switch ( index ) {
+    case STRID_LANGID:
+      memcpy(&_desc_str[1], string_desc_arr[0], 2);
+      chr_count = 1;
+      break;
+
+    case STRID_SERIAL:
+      chr_count = board_usb_get_serial(_desc_str + 1, 32);
+      break;
+
+    default:
+      // Note: the 0xEE index string is a Microsoft OS 1.0 Descriptors.
+      // https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/microsoft-defined-usb-descriptors
+
+      if ( !(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])) ) return NULL;
+
+      const char *str = string_desc_arr[index];
+
+      // Cap at max char
+      chr_count = strlen(str);
+      size_t const max_count = sizeof(_desc_str) / sizeof(_desc_str[0]) - 1; // -1 for string type
+      if ( chr_count > max_count ) chr_count = max_count;
+
+      // Convert ASCII string into UTF-16
+      for ( size_t i = 0; i < chr_count; i++ ) {
+        _desc_str[1 + i] = str[i];
+      }
+      break;
+  }
+
+  // first byte is length (including header), second byte is string type
+  _desc_str[0] = (uint16_t) ((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
+
+  return _desc_str;
+}

examples/mass-storage/arm7/source/usb_descriptors.h

@@ -0,0 +1,7 @@
+#pragma once
+
+enum
+{
+    ITF_NUM_MSC,
+    ITF_NUM_TOTAL
+};