usbd_topology(), usbd_topology_ext()

Get the USB bus physical topology

Synopsis:

#include <sys/usbdi.h>

int usbd_topology( struct usbd_connection *connection,
                   usbd_bus_topology_t *tp )

int usbd_topology_ext( struct usbd_connection *connection,
                       uint8_t busno,
                       usbd_bus_topology_t *tp )

Arguments:

connection: An opaque handle that identifies the USB stack, obtained by calling usbd_connect().
bus: (usbd_topology_ext() only) The index of the bus that you want the topology for.
tp: A pointer to a usbd_bus_topology_t data structure that this function fills in; see below.

Description:

You can use the usbd_topology() or usbd_topology_ext() function to get the USB bus physical topology.

For more information on USB bus topology, see sections 4.1.1 and 5.2.3 in the USB Specification v1.1.

If your system has more than one bus, you can call usbd_topology_ext() to get information about a specific one. The usbd_topology() function gets information about the first bus; calling it is the same as calling usbd_topology() with a bus argument of 0.

The usbd_bus_topology_t structure is defined as follows:

typedef struct usbd_port_attachment {
    uint8_t  upstream_devno;
    uint8_t  upstream_port;
    uint8_t  upstream_port_speed;
    uint8_t  upstream_hc;
    uint8_t  _reserved[4];
} usbd_port_attachment_t;

typedef struct usbd_bus_topology {
    usbd_port_attachment_t    ports[64];
} usbd_bus_topology_t;

The structure contains an array of usb_port_attachment_t structures, one per device. The usb_port_attachment_t structure contains at least the following:

upstream_devno

The device number of the upstream hub (0 if it's a root port).

upstream_port

The port number the device is connected to.

upstream_port_speed

The port speed that the device is operating at; one of the following:

0 — full
1 — low
2 — high

upstream_hc

The bus or host controller that the device is connected to.

The upstream_devno field will contain a value other than 0xff to indicate a valid attachment.

Returns:

EOK: Success.
ENODEV: The device was removed.

Classification:

QNX Neutrino, QNX 4

Safety:
Cancellation point	Yes
Interrupt handler	No
Signal handler	No
Thread	Yes