usb: xhci: Add NVIDIA Tegra XUSB controller driver

Add support for the on-chip XUSB controller present on Tegra SoCs. This
controller, when loaded with external firmware, exposes an interface
compliant with xHCI. This driver loads the firmware, starts the
controller, and is able to service host-specific messages sent by the
controller's firmware.

The controller also supports USB device mode as well as powergating
of the SuperSpeed and host-controller logic when not in use, but
support for these is not yet implemented.

Based on work by:
  Ajay Gupta <ajayg@nvidia.com>
  Bharath Yadav <byadav@nvidia.com>
  Andrew Bresticker <abrestic@chromium.org>

Cc: Mathias Nyman <mathias.nyman@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/usb/host/Kconfig

@@ -69,6 +69,15 @@ config USB_XHCI_RCAR
 	  Say 'Y' to enable the support for the xHCI host controller
 	  found in Renesas R-Car ARM SoCs.
 
+config USB_XHCI_TEGRA
+	tristate "xHCI support for NVIDIA Tegra SoCs"
+	depends on PHY_TEGRA_XUSB
+	depends on RESET_CONTROLLER
+	select FW_LOADER
+	---help---
+	  Say 'Y' to enable the support for the xHCI host controller
+	  found in NVIDIA Tegra124 and later SoCs.
+
 endif # USB_XHCI_HCD
 
 config USB_EHCI_HCD

drivers/usb/host/Makefile

@@ -68,6 +68,7 @@ obj-$(CONFIG_USB_XHCI_HCD)	+= xhci-hcd.o
 obj-$(CONFIG_USB_XHCI_PCI)	+= xhci-pci.o
 obj-$(CONFIG_USB_XHCI_PLATFORM) += xhci-plat-hcd.o
 obj-$(CONFIG_USB_XHCI_MTK)	+= xhci-mtk.o
+obj-$(CONFIG_USB_XHCI_TEGRA)	+= xhci-tegra.o
 obj-$(CONFIG_USB_SL811_HCD)	+= sl811-hcd.o
 obj-$(CONFIG_USB_SL811_CS)	+= sl811_cs.o
 obj-$(CONFIG_USB_U132_HCD)	+= u132-hcd.o