Deprecate cortex-m-rtic-trace

[tmplt]

A goal of RTIC Scope is to be as non-intrusive as possible which ultimately requires us to remove the use of cortex-m-rtic-trace: probe-rs should be able to configure almost everything instead. Ideally, the only thing the user should need to do is declare a [package.metadata.rtic-scope] block in Cargo.toml ¹ (or equivalent file). Some functionality must be moved upstream into RTIC itself such as the variable that the DWT monitors for software tracing purposes. The user may also have to set a flag in order to signal which RTIC tasks they want to trace, e.g. #[task(trace = true, ...)], but this is more of a boon as it enables the user to trace a subset of tasks.

Footnotes

1. for example:

   [package.metadata.rtic-scope]
   # necessary information for RTIC metadata recovery
   pac_name = "stm32f4"
   pac_features = ["stm32f401"]
   pac_version = "0.13"
   interrupt_path = "stm32f4::stm32f401::Interrupt"
   
   # ITM/DWT/TPIU parameters that probe-rs could set that cortex-m-rtic-trace currently handles.
   tpiu_freq = 16000000
   tpiu_baud = 115200
   dwt_enter_id = 1
   dwt_exit_id = 2
   lts_prescaler = 1
   
   # for debugging purposes: reading from the embedded trace buffer via probe-rs seems to yield a lot of broken packages.
   # To be investigated.
   expect_malformed = true
   

   ↩

[tmplt]

CC @Yatekii @perlindgren: future PRs to both probe-rs and cortex-m-rtic will stem from this tracking issue.

[tmplt]

Related to, and depends on rtic-rs/rfcs#51 closing.

[tmplt]

Depends on probe-rs/probe-rs#727.