Nothing in the controller driver is PCI-specific beyond finding the
registers and the interrupt, so an SoC wiring an xHCI controller
directly could not use any of it.
usbhost_xhci.c is now the driver; usbhost_xhci_pci.c is the PCI
attachment, holding the ID table, the BAR mapping and the MSI-X vector.
include/nuttx/usb/xhci.h carries what passes between them: the register
base, a way to attach the interrupt, and a name to report the controller
by, since a system may have more than one.
The interrupt belongs to the bus: the bus attaches and detaches it, and
the driver never holds an interrupt number.
USBHOST_XHCI is the driver and is not selectable on its own;
USBHOST_XHCI_PCI selects it. Another bus adds its own symbol beside it.
No functional change intended.
Assisted-by: Claude:claude-opus-5
Signed-off-by: Justin Hammond <justin@dynam.ac>
82fb0d8d06