Create two USB MSC using different partitions, with access to only one partition (IEC-468)

[PR2403]

Answers checklist.

• I have read the component documentation ESP-IDF Components and the issue is not addressed there.
• I am using target and esp-idf version as defined in component's idf_component.yml
• I have searched the issue tracker for a similar issue and not found any related issue.

Which component are you using? If you choose Other, provide details in More Information.

device/esp_tinyusb

ESP-IDF version.

v5.5.1

Development Kit.

custom esp32s3 n16r8

Used Component version.

2.0.1~1

More Information.

I saw #define TINYUSB_MSC_STORAGE_MAX_LUNS 2
run the code

static esp_err_t storage_init_spiflash(wl_handle_t *wl_handle, char *label)
{
    char TAG[] = "usb_msc_test";
    ESP_LOGI(TAG, "Initializing wear levelling");

    const esp_partition_t *data_partition = esp_partition_find_first(ESP_PARTITION_TYPE_DATA, ESP_PARTITION_SUBTYPE_DATA_FAT, label);
    if (data_partition == NULL)
    {
        ESP_LOGE(TAG, "Failed to find FATFS partition. Check the partition table.");
        return ESP_ERR_NOT_FOUND;
    }

    return wl_mount(data_partition, wl_handle);
}
void usb_msc_test(void *arg)
{
    char TAG[] = "usb_msc_test";
    ESP_LOGI(TAG, "Initializing storage...");

    wl_handle_t wl_handle = WL_INVALID_HANDLE;

    ESP_ERROR_CHECK(storage_init_spiflash(&wl_handle, "lua"));

    tinyusb_msc_storage_handle_t storage_hdl = NULL;

    tinyusb_msc_storage_config_t storage_cfg;
    memset(&storage_cfg, 0, sizeof(storage_cfg));
    storage_cfg = {
        .medium = {.wl_handle = wl_handle},
        .fat_fs = {
            .base_path = "/usb", // User specific base path
        },
        .mount_point = TINYUSB_MSC_STORAGE_MOUNT_USB, // Initial mount point to APP
    };

    ESP_ERROR_CHECK(tinyusb_msc_new_storage_spiflash(&storage_cfg, &storage_hdl));

    wl_handle_t wl_handle2 = WL_INVALID_HANDLE;

    ESP_ERROR_CHECK(storage_init_spiflash(&wl_handle2, "lua_2"));

    tinyusb_msc_storage_handle_t storage_hdl2 = NULL;

    tinyusb_msc_storage_config_t storage_cfg2;
    memset(&storage_cfg2, 0, sizeof(storage_cfg2));
    storage_cfg2 = {
        .medium = {.wl_handle = wl_handle2},
        .fat_fs = {
            .base_path = "/usb_2", // User specific base path
        },
        .mount_point = TINYUSB_MSC_STORAGE_MOUNT_USB, // Initial mount point to APP
    };

    ESP_ERROR_CHECK(tinyusb_msc_new_storage_spiflash(&storage_cfg2, &storage_hdl2));

    const tinyusb_config_t tusb_cfg = TINYUSB_DEFAULT_CONFIG();
    ESP_ERROR_CHECK(tinyusb_driver_install(&tusb_cfg));
}

partitions.csv

nvs,      data, nvs,     0x9000,  0x6000,
phy_init, data, phy,     0xf000,  0x1000,
factory,  app,  factory, 0x10000, 1M,
lua,      data, fat,     ,        1M,
lua_2,    data, fat,     ,        1M,

on host, it shows 2 usb disk, but they are the same partition, they have same content

[github-actions]

Hi @PR2403! Please be aware that the following suggestions are generated by a bot and haven't been fact-checked by Espressif Systems. We hope that this message will help you until an Espressif Engineer looks at your issue.

---

To implement multiple USB Mass Storage (MSC) Logical Units (LUNs) using different partitions on an ESP32-S3, you need to ensure each storage instance is correctly mapped to its own wl_handle and that the tinyusb_msc_storage_config_t is properly initialized for each LUN.

Based on the documentation for the esp_tinyusb component (v2.0.0+), here are the key points to address the issue of both disks showing the same content:

1. Correct Configuration Initialization

In your code, you are using C99 compound literals to assign values to storage_cfg after a memset. Ensure that all fields are correctly cleared and populated. When adding multiple storages, the esp_tinyusb stack internally assigns them to sequential LUNs (LUN 0, LUN 1, etc.) [USB Mass Storage Device (MSC)].

2. Implementation Logic

The knowledge sources indicate that for Dual Storage (or multiple partitions), you should call tinyusb_msc_new_storage_spiflash for each partition with its unique wl_handle. The stack will then map these to separate LUNs [USB Mass Storage Device (MSC)].

Your provided code appears logically correct regarding the handles, but ensure the following:

• Partition Subtype: Your storage_init_spiflash uses ESP_PARTITION_SUBTYPE_DATA_FAT. Ensure your partitions.csv entries for lua and lua_2 actually use the fat subtype (which usually maps to 0x81).
• Configuration Scope: Ensure the tinyusb_msc_storage_config_t structures are not being overwritten or pointing to the same memory if passed by reference in a way that conflicts.

3. Recommended Code Pattern

Derived from the component documentation, ensure your setup follows this pattern:

// ... initialization of wl_handle1 for "lua" and wl_handle2 for "lua_2" ...

// Configuration for first LUN (lua)
tinyusb_msc_storage_handle_t storage_hdl1;
const tinyusb_msc_storage_config_t cfg1 = {
    .medium.wl_handle = wl_handle1,
    // Add other fields like base_path if needed
};
ESP_ERROR_CHECK(tinyusb_msc_new_storage_spiflash(&cfg1, &storage_hdl1));

// Configuration for second LUN (lua_2)
tinyusb_msc_storage_handle_t storage_hdl2;
const tinyusb_msc_storage_config_t cfg2 = {
    .medium.wl_handle = wl_handle2,
};
ESP_ERROR_CHECK(tinyusb_msc_new_storage_spiflash(&cfg2, &storage_hdl2));

// Finally install the driver
const tinyusb_config_t tusb_cfg = TINYUSB_DEFAULT_CONFIG();
ESP_ERROR_CHECK(tinyusb_driver_install(&tusb_cfg));

[USB Mass Storage Device (MSC)]

4. Potential Constraints

• LUN Limit: You noted TINYUSB_MSC_STORAGE_MAX_LUNS is 2. Ensure this is set correctly in your menuconfig under Component config -> TinyUSB Stack -> MSC Class -> Max number of LUNs. If this is set to 1, the second storage registration might fail or behave unexpectedly.
• Mounting: If you set mount_point = TINYUSB_MSC_STORAGE_MOUNT_USB, the storage is exposed to the Host (PC). If the Host sees the same content, verify that wl_mount is actually returning two different valid handles for the two different partition labels [USB Mass Storage Device (MSC)].

If the issue persists despite using distinct handles and configurations, double-check that the wl_handle returned for "lua_2" is not accidentally the same as "lua" due to a partition table mismatch or an error in the storage_init_spiflash function.

[igi540]

Hi @PR2403,
it is currently not supported. The component README literally says:

SPI-Flash Storage: “MSC Class will have one LUN, mapped to SPI/Flash storage”.

Dual Storage: “MSC Class will have two LUNs, mapped to SPI/Flash and SD/MMC”.

[igi540]

Hi @PR2403,,
could you explain the use case and what problem separate LUNs solve for you?

[PR2403]

Hi @igi540 , One partition is used to store configuration files, where users can edit the file. Another partition is used to store Lua files, which is not normally accessible to users. It can only be accessed by entering a password in the console for debugging purposes