usb: dwc3: gadget: Avoid using reserved endpoints on Intel Merrifield

usb: dwc3: gadget: Avoid using reserved endpoints on Intel Merrifield

[ Upstream commit 461f24bff86808ee5fbfe74751a825f8a7ab24e0 ]

Intel Merrifield SoC uses these endpoints for tracing and they cannot
be re-allocated if being used because the side band flow control signals
are hard wired to certain endpoints:

• 1 High BW Bulk IN (IN#1) (RTIT)
• 1 1KB BW Bulk IN (IN#8) + 1 1KB BW Bulk OUT (Run Control) (OUT#8)

In device mode, since RTIT (EP#1) and EXI/RunControl (EP#8) uses
External Buffer Control (EBC) mode, these endpoints are to be mapped to
EBC mode (to be done by EXI target driver). Additionally TRB for RTIT
and EXI are maintained in STM (System Trace Module) unit and the EXI
target driver will as well configure the TRB location for EP #1 IN
and EP#8 (IN and OUT). Since STM/PTI and EXI hardware blocks manage
these endpoints and interface to OTG3 controller through EBC interface,
there is no need to enable any events (such as XferComplete etc)
for these end points.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Ferry Toth <fntoth@gmail.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20250212193116.2487289-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>