USB services
One symbol in USB-sysmodule is: "vtable for nn::usb::detail::UsbComplexTegra21x".
usb:ds
Used for Switch<>PC USB comms, aka Switch-as-device. This service is used during factory setup by manu.
This service session is used as an IPC domain by manu. All of these {get-session} commands also return an output u8 and the u32 <domainID>, for using those sessions as domains.
| Cmd | Name | Notes |
|---|---|---|
| 0 | #BindDevice | |
| 1 | #BindClientProcess | |
| 2 | #GetDsInterface | |
| 3 | #GetStateChangeEvent | |
| 4 | No input. Returns an output u32. | |
| 5 | #SetVidPidBcd |
Initialization done by manu:
- Initial service init:
- Get service/etc.
- Uses #BindDevice.
- Uses #BindClientProcess.
- Uses #GetStateChangeEvent.
- Uses #SetVidPidBcd.
- Interface init:
- Uses #GetDsInterface, then uses commands from that with the rest of the following.
- Uses #GetSetupEvent.
- Uses #GetCtrlInCompletionEvent.
- Uses #GetCtrlOutCompletionEvent.
- Initializes two endpoints via using #GetDsEndpoint twice.
Configuration
The following is the default USB config strings, while the usbds service isn't being used. All of the below configuration will reset to the defaults when all usbds-related sessions are closed. These can be set with #SetVidPidBcd. The default string for Product is loaded from settings config.
Product: Nintendo Switch Manufacturer: Nintendo SerialNumber: SerialNumber
The following is the default lsusb -v {...} output when the usbds service wasn't used.
The endpoints are configured using #GetDsEndpoint, the total number of endpoints is the number of open #IDsEndpoint sessions. bInterfaceNumber is {0-based index for the enabled #IDsInterface session.} Some of the interface fields are configured using #GetDsInterface.
Bus 003 Device 006: ID 057e:2000 Nintendo Co., Ltd
Couldn't open device, some information will be missing
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x057e Nintendo Co., Ltd
idProduct 0x2000
bcdDevice 1.00
iManufacturer 1
iProduct 2
iSerial 3
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 34
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower {...}
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 0 No Subclass
bInterfaceProtocol 0 None
iInterface 0
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 2.00
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 26
Report Descriptors:
** UNAVAILABLE **
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0001 1x 1 bytes
bInterval 16
BindDevice
Takes an u32 (complexId). Manu sends 0x02.
Binding more than once with the current session is not allowed. Once this command is used, the USB device will not be listed with lsusb until #EnableInterface is used.
BindClientProcess
Takes 1 copy-handle for the current process (0xFFFF8001).
GetDsInterface
Takes 2 type-5 buffers and returns an #IDsInterface. Manu sends a 0x09-byte command (e.g.: 0x09, 0x04, 0x04, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0x00) in the first buffer and a string ("usb") in the second buffer.
When the strlen output for the second buffer is >=0x40, size 0x40 is used instead for copying the string. This is the interface name, it's not sent over USB.
Returns an error when #BindDevice wasn't used.
Structure of the first buffer(this is similar to libusb__interface__descriptor):
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0x1 | bLength. Must match 0x9. |
| 0x1 | 0x1 | bDescriptorType. Must match 0x4. |
| 0x2 | 0x1 | When 0x4, an error will be thrown if certain state checks don't pass. Otherwise, this must be <=3. |
| 0x3 | 0x1 | Must match 0x0. |
| 0x4 | 0x1 | ? |
| 0x5 | 0x1 | bInterfaceClass |
| 0x6 | 0x1 | bInterfaceSubClass |
| 0x7 | 0x1 | bInterfaceProtocol |
| 0x8 | 0x1 | ? |
Only the first 0x9-bytes are used.
GetStateChangeEvent
Returns an event handle for state changes.
SetVidPidBcd
Takes a type-5 buffer with 0x66 bytes of USB descriptor data (see manu).
| Offset | Size | Description |
|---|---|---|
| 0x0 | 0x2 | VID (idVendor) |
| 0x2 | 0x2 | PID (idProduct) |
| 0x4 | 0x2 | bcdUSB |
| 0x6 | 0x20 | Manufacturer |
| 0x26 | 0x20 | Product |
| 0x46 | 0x20 | SerialNumber |
The last 3 blocks are strings. The data following each string is all-zero, for padding to size 0x20.
IDsInterface
| Cmd | Name | Notes |
|---|---|---|
| 0 | #GetDsEndpoint | |
| 1 | #GetSetupEvent | |
| 2 | Takes a type-0x6 output buffer, no other output. | |
| 3 | #EnableInterface | |
| 4 | #DisableInterface | |
| 5 | Takes an u32 and an u64. Returns an output u32. | |
| 6 | Takes an u32 and an u64. Returns an output u32. | |
| 7 | #GetCtrlInCompletionEvent | |
| 8 | No input. Returns 0x84 bytes of output. | |
| 9 | #GetCtrlOutCompletionEvent | |
| 10 | No input. Returns 0x84 bytes of output. | |
| 11 | No input/output. |
GetDsEndpoint
Takes a type-5 buffer and returns an #IDsEndpoint. Manu uses this twice for getting two endpoint sessions, with the following 0x7-byte buffer data:
- First endpoint: 0x07, 0x05, 0x80, 0x02, 0x00, 0x02, 0x00.
- Second endpoint: Same as above except byte2 is 0x00.
Each field is an u8, except for offset 0x4-0x5 which is an u16.
This structure matches libusb_endpoint_descriptor.
GetSetupEvent
Returns an event handle for interface setup changes.
EnableInterface
Takes no arguments. Enables the current interface.
Only one interface can be enabled at time, this indicates which interface is actually used for USB.
DisableInterface
Takes no arguments. Disables the current interface.
GetCtrlInCompletionEvent
Returns an event handle for polling the completion of input control commands.
GetCtrlOutCompletionEvent
Returns an event handle for polling the completion of output control commands.
IDsEndpoint
| Cmd | Name | Notes |
|---|---|---|
| 0 | #PostBufferAsync | |
| 1 | No input/output. | |
| 2 | No input. Returns an output handle? | |
| 3 | #GetReportData | |
| 4 | No input/output. | |
| 5 | Takes an input u8, no output. |
PostBufferAsync
Takes an u32 (size) and an u64 (buffer). Returns an output u32.
GetReportData
Returns 0x84 bytes of report data from the endpoint.
usb:hs
General USB devices usage, used by hid-sysmodule and bsdsockets-sysmodule.
usb:pd
usb:pd:c
USB-sysmodule symbols for this refer to "Cradle", which is the Dock.
usb:pm
Presumably Power Management, only system-title using this is PTM.