driver.bus.usb.hub¶

USB hub class driver for multi-level port topology.

Overview¶

This unit implements the USB hub class driver. It handles hub device initialisation, power sequencing, port status polling, and hotplug detection. When a new device is detected on a hub port, it calls back into driver.bus.usb.core to enumerate the downstream device. This enables multi-level USB topologies.

Dependencies¶

driver.bus.usb.types
driver.bus.usb.core
driver.mgr
syslog

Constants¶

Hub Feature Selectors¶

HUB_FEAT_C_HUB_LOCAL_POWER, HUB_FEAT_C_HUB_OVER_CURRENT.

Port Feature Selectors¶

PORT_FEAT_CONNECTION, PORT_FEAT_ENABLE, PORT_FEAT_SUSPEND, PORT_FEAT_OVER_CURRENT, PORT_FEAT_RESET, PORT_FEAT_POWER, PORT_FEAT_LOW_SPEED, PORT_FEAT_C_CONNECTION, PORT_FEAT_C_ENABLE, PORT_FEAT_C_SUSPEND, PORT_FEAT_C_OVER_CURRENT, PORT_FEAT_C_RESET.

Hub Request Codes¶

HUB_REQ_GET_STATUS, HUB_REQ_CLEAR_FEATURE, HUB_REQ_SET_FEATURE, HUB_REQ_GET_DESCRIPTOR, HUB_REQ_GET_PORT_STATUS.

Port Status Bits¶

PORT_STATUS_CONNECTION ($0001), PORT_STATUS_ENABLE ($0002), PORT_STATUS_SUSPEND ($0004), PORT_STATUS_OVER_CURRENT ($0008), PORT_STATUS_RESET ($0010), PORT_STATUS_POWER ($0100), PORT_STATUS_LOW_SPEED ($0200), PORT_STATUS_HIGH_SPEED ($0400).

Port Change Bits¶

PORT_CHANGE_CONNECTION ($0001), PORT_CHANGE_ENABLE ($0002), PORT_CHANGE_SUSPEND ($0004), PORT_CHANGE_OVER_CURRENT ($0008), PORT_CHANGE_RESET ($0010).

Types¶

TUSBHubPortStatus¶

TUSBHubPortStatus = packed record
  wPortStatus : uint16;
  wPortChange : uint16;
end;

Returned by GET_PORT_STATUS requests. wPortStatus holds current port state bits; wPortChange holds change flags that must be cleared by the driver.

TUSBHubData¶

Internal per-hub state record. Holds a pointer to the TUSBDevice, the hub descriptor, port count, power-on delay, and per-port state.

Functions and Procedures¶

init¶

procedure init;

Registers the hub class driver with driver.mgr for USB devices with class $09.

load¶

function load(ptr: pointer): boolean;

Driver load callback. Reads the hub descriptor, powers on all ports, and adds the hub to the polling list.

poll_hubs¶

procedure poll_hubs;

Called periodically. Sends GET_PORT_STATUS to each port of each registered hub. On detecting PORT_CHANGE_CONNECTION, resets the port and calls driver.bus.usb.core.enumerate_device or usb_remove_device as appropriate.

UnitTest¶

procedure UnitTest;

Verifies port status bit constant values.

Notes¶

Hub polling is driven by the USB core's poll_all mechanism rather than hardware interrupts.
bPwrOn2PwrGood from the hub descriptor (in units of 2 ms) is respected when powering on ports.