This commit refactors the USBH and the USB Host Library in the following ways:
- USBH now presents an abstraction of an endpoint (via usbh_ep_handle_t)
- Added separate functions to enqueue/dequeue URBs to a particular endpoint
- USB Host Library no longer calls HCD API directly. Calls USBH endpoint API
instead.
- Renamed "notif_cb" to "proc_req_cb" (Processing Request Callback)
- This is to avoid confusion with FreerTOS task notifications and Host
Library client event notifications.
- The processing functions of each layer (i.e., "xxx_process()") request
calls via the "proc_req_cb"
- The main handling function (i.e., usb_host_lib_handle_events()) is
responsible for calling the required "xxx_process()" of each layer
This commit adds the preliminary version of the USB Host Library. This commit contains:
- USBH (USB Host Driver)
- Hub Driver that only supports a single device and device enumeration
- USB Host Library (asychronous API)
- Test cases for USB Host Library asychronous API
The following changes were made to the existing HCD:
- Removed HCD_PIPE_STATE_INVALID. Pipes are no longer invalidated
- Changed pipe commands to halt, flush, and clear. Pipes need to be manually
halted, flush, and cleared.
- Halting and flushing a pipe will execute the pipe callback if it causes a
HCD_PIPE_EVENT_URB_DONE event
