In case both periph_gpio_irq and periph_gpio_ll_irq are used, the
periph_gpio_irq implementation now uses periph_gpio_ll_irq, so that
they can coexist.
clock.c: The MSP430 may need nop instructions after (and in some cases
even before) touching the global interrupt enable bit in the
status register. The assembler generates a warning when in
doubt. Those nops should not be needed in our cases, but maybe
it is better two waste flash for two instructions than having
to live with the warning.
cpu.c: drop unneeded include
The assumption that every MCU has this feature turned out wrong. Hence,
add a feature to allow testing for support of edge triggered IRQs on
both flanks.
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
`thread_measure_stack_free()` previously assumed that reading past the
stack is safe. When the stack was indeed part of a thread, the
`thread_t` structure is put after the stack, increasing the odds of
this assumption to hold. However, `thread_measure_stack_free()` could
also be used on the ISR stack, which may be allocated at the end of
SRAM.
A second parameter had to be added to indicate the stack size, so that
reading past the stack can now be prevented.
This also makes valgrind happy on `native`/`native64`.
This changes a bunch of things that allows building with the musl C lib,
provided that `libucontext-dev` and `pkg-config` are installed.
Note that installing libucontext makes absolutely zero sense on C libs
that do natively provide this deprecated System V API, such as glibc.
Hence, it no sane glibc setup is expected to ever have libucontext
installed.
A main pain point was that argv and argc are expected to be passed to
init_fini handlers, but that is actually a glibc extension. This just
parses `/proc/self/cmdline` by hand to populate argv and argc during
startup, unless running on glibc.
