Image Signal Processor is a co-processor in charge of Facetime camera
in Apple laptops. This tracer is based on ISP found in M1 processor.
The ISP in M1 SoC exposes seven inter-process communication channels.
Using those channels Application Processor (AP) can perform a variety of
task in the ISP and viceversa. All channels seems to be bidirectional, with
unique exception of TERMINAL channel.
DART translation is used often to translate control structures passed
over IPC channels to IO virtual addresses.
How those channels are used is still unclear but tracer should allow us
to dive deep on high-level protocol to communicate with Facetime camera.
ISP exposes also some I2C peripheral and SPMI registers but I haven't
dive into their working or purpose.
Signed-off-by: Kellerman Rivero <krsloco@gmail.com>
