Digibird1 DMA example: why ALT_STM_OFST used as offset for the LW bridge

I have been using the DMA example which is provided on:


Basically it works and and I am now moving some of the mmap stuff into a driver.

The is one thing I do not understand:

For configuring the DMA peripheral the lightweight bridge is used.
The LW brigde has offset: 0xff200000

I would expect to mmap 0xff200000 + DMA module offset for configuration.

In the example however ALT_STM_OFFS ( trace module 0xfc000000) is mmapped
after which the offset of the LW bridge and the DMA module are added.

Why is the trace module offset included here ?