This started while adding USB MIDI support (and descriptor support is
in this change.) When seeing that I'd have to implement the MIDI class
logic twice, once for atmel-samd and once for nrf, I decided to refactor
the USB stack so its shared across ports. This has led to a number of
changes that remove items from the ports folder and move them into
supervisor.
Furthermore, we had external SPI flash support for nrf pending so I
factored out the connection between the usb stack and the flash API as
well. This PR also includes the QSPI support for nRF.
This allows for the heap to fill all space but the stack. It also
allows us to designate space for memory outside the runtime for
things such as USB descriptors, flash cache and main filename.
Fixes#754
* atmel-samd: Add support for internal filesystems.
This allows us to re-enable `os`. `random` is also enabled because
it solely depends on `os`.
Fixes#266. Its also a pre-requisite for #260.
* atmel-samd: Update SAMD51 linker script comments and MICROPY_MAX_STACK_USAGE enabling.
* atmel-samd: Remove ASF3. This will break builds.
* atmel-samd: Add ASF4 for the SAMD21 and SAMD51.
* Introduce the supervisor concept to facilitate porting.
The supervisor is the code which runs individual MicroPython VMs. By
splitting it out we make it more consistent and easier to find.
This also adds very basic SAMD21 and SAMD51 support using the
supervisor. Only the REPL currently works.
This begins the work for #178.
