usb: tegra: support device mode

A few changes are made to the Tegra EHCI driver so that it can set
everything up for device-mode operation on the first USB controller.
This can be used in conjunction with ci_udc.c to operate as a USB
device.

Detailed changes are:

* Rename set_host_mode() to set_up_vbus() since that's really what it
  does.

* Modify set_up_vbus() to know whether it's initializing in host or
  device mode, and:

  - Skip the external VBUS check in device mode, since external VBUS is
    expected in this case.

  - Disable VBUS output in device mode.

* Modify init_phy_mux() to know whether it's initializing in host or
  device mode, and hence skip setting USBMODE_CM_HC (which enables host
  mode) in device mode. See the comments in that function for why this
  is safe w.r.t. the ordering requirements of PHY selection.

* Modify init_utmi_usb_controller() to force "b session valid" in device
  mode, since the HW requires this. This is done in UTMI-specific code,
  since we only support device mode on the first USB controller, and that
  controller can only talk to a UTMI PHY.

* Enhance ehci_hcd_init() to error-check the requested host-/device-mode
  vs. the dr_mode (dual-role mode) value present in device tree, and the
  HW configurations which support device mode.

* Enhance ehci_hcd_init() not to skip HW initialization when switching
  between host and device mode on a controller. This requires remembering
  which mode the last initialization used.

Cc: Jim Lin <jilin@nvidia.com>
Cc: Stefan Agner <stefan@agner.ch>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/arm/include/asm/arch-tegra/usb.h b/arch/arm/include/asm/arch-tegra/usb.h
index ceb7bcd9cf..c817088fa5 100644
--- a/arch/arm/include/asm/arch-tegra/usb.h
+++ b/arch/arm/include/asm/arch-tegra/usb.h
@@ -349,6 +349,8 @@ struct usb_ctlr {
 
 /* USB3_IF_USB_PHY_VBUS_SENSORS_0 */
 #define VBUS_VLD_STS			(1 << 26)
+#define VBUS_B_SESS_VLD_SW_VALUE	(1 << 12)
+#define VBUS_B_SESS_VLD_SW_EN		(1 << 11)
 
 /* Setup USB on the board */
 int usb_process_devicetree(const void *blob);