expose SerialBase interrupt control methods in UARTSerial

[bmcdonnell-ionx]

Description

These methods should be exposed in UARTSerial like they are in Serial, right?

I haven't tested this yet, since I'm still trying to figure out how to conditionally sleep / wake on interrupt. Input on that question thread is welcome, so that I can test this PR.

It builds, though, and seems like it ought to work.

Pull request type

• Fix
• Refactor
• New target
• Feature
• Breaking change

[kjbracey]

Nope, you should be using the generic FileHandle mechanisms here. Everything you need is in FileHandle. The tools are FileHandle::set_blocking/sigio/read/write, and mbed::poll().

Note if using UARTSerial you don't care about interrupts directly - you care about data or space in the buffers. UARTSerial provides that info via the generic FileHandle calls.

I had prepared a bunch of Handbook examples for UARTSerial/FileHandle based on the Serial ones showing the equivalent forms, but I think they got lost in the review ether.

In the tree you can see examples in https://github.com/ARMmbed/mbed-os/blob/master/platform/ATCmdParser.cpp and https://github.com/ARMmbed/mbed-os/blob/master/features/FEATURE_LWIP/lwip-interface/ppp_lwip.cpp. The second one uses interrupt-driven input - stream_cb -> ppp_input - mixed with blocking output - ppp_output.

Note that neither of them know anything about serial - they would work with any FileHandle stream device. (But the word serial occurs once in a comment. Pah).

The FileHandle APIs are basically the same as POSIX/Linux/whatever - just Google nonblocking/asynchronous IO.

[bmcdonnell-ionx]

@kjbracey-arm, I'll look into your suggestions a bit later. It seems that you've addressed my wrong approach, so please close this as "don't merge" / wontfix for now.

[0xc0170]

Please reopen if any update