When the kernel side of FastRPC fails, the return value is -1 and errno
is set. When the remote side of FastRPC fails, the return value is an
AEE error code. It is not specialized for the reverse tunnel. Add an
error API that can convert the return value to a string-based error.
The method call format as interpreted last time had some limitations.
First, input words could not appear after the input buffers, making it
impossible to represent the apps_std_mkdir method accurately. Second, it
was assumed that the lengths in the primary input buffer represent the
number of bytes. In reality, the lengths represent the number of
elements, which just happened to be octets in the majority of remote
methods found, and the adsp_perf_get_usecs remote method could not be
represented. Update the format for the third time to remove these
limitations.
This format allows the mixing of words and lengths of other buffers in
the primary buffer by using 0 to denote words in an array of arguments.
It also allows a greater size of elements, denoted by any non-zero
value.
The FastRPC implementation is loosely related to the sensor shell. It is
useful to provide interfaces over FastRPC for sensor DSP firmware, and
enables the sensor shell to provide most physical sensors. However, the
FastRPC implementation has no meaningful connection with the sensor
shell in terms of code. Move the FastRPC implementation to the project
root to make it more intuitive to install and use and to separate it
from a distinct project.
