Running
USEMODULE=stdio_rtt make BOARD=weact-g030f6 -C ... flash term
failed due the programmer not being specified by the time the serial
is configured:
makefiles/tools/serial.inc.mk:44: "Warning: No RIOT_TERMINAL set,
but using stdio_rtt: The default terminal is likely not to work."
This reorders the setup of the board to first configure the programmer
and then the serial, so that using stdio_rtt now works out of the box.
A test intended to ensure that a configuration toggling the direction
of a GPIO two times restores the original configuration not only
compared the configuration at the two points in time, but also the
value of the input buffer. Since a floating input reads back random
values when not externally driven, the test was actually randomly
failing. Apparently I got lucky before consistently and this never
triggered until now.
This now clears the input value from both the configuration reported
before and after toggling the direction twice and should now indeed
succeed consistently.
This fixes a race in `LED<NUM>_TOGGLE`, which is a read-copy-write
operation. Any access to a GPIO pin on the same GPIO port that
happens concurrently could result in data corruption. Using the
GPIO LL API, which is thread-safe, fixes the issue.
Note: The used GPIO LL functions will work even in when the GPIO LL
module is not used.
The API was based on the assumption that GPIO ports are mapped in memory
sanely, so that a `GPIO_PORT(num)` macro would work allow for constant
folding when `num` is known and still be efficient when it is not.
Some MCUs, however, will need a look up tables to efficiently translate
GPIO port numbers to the port's base address. This will prevent the use
of such a `GPIO_PORT(num)` macro in constant initializers.
As a result, we rather provide `GPIO_PORT_0`, `GPIO_PORT_1`, etc. macros
for each GPIO port present (regardless of MCU naming scheme), as well as
`GPIO_PORT_A`, `GPIO_PORT_B`, etc. macros if (and only if) the MCU port
naming scheme uses letters rather than numbers.
These can be defined as macros to the peripheral base address even when
those are randomly mapped into the address space. In addition, a C
function `gpio_port()` replaces the role of the `GPIO_PORT()` and
`gpio_port_num()` the `GPIO_PORT_NUM()` macro. Those functions will
still be implemented as efficient as possible and will allow constant
folding where it was formerly possible. Hence, there is no downside for
MCUs with sane peripheral memory mapping, but it is highly beneficial
for the crazy ones.
There are also two benefits for the non-crazy MCUs:
1. We can now test for valid port numbers with `#ifdef GPIO_PORT_<NUM>`
- This directly benefits the test in `tests/periph/gpio_ll`, which
can now provide a valid GPIO port for each and every board
- Writing to invalid memory mapped I/O addresses was treated as
triggering undefined behavior by the compiler and used as a
optimization opportunity
2. We can now detect at compile time if the naming scheme of the MCU
uses letters or numbers, and produce more user friendly output.
- This is directly applied in the test app
