soc: arm: nordic: provide custom busy_wait implementations

[pabigot]

Implementation taken from Nordic nrfx version 1.3.1 soc/nrfx_coredep.h,
modified to remove material from other series and to conform to Zephyr
coding standards.

Note that unlike standard k_busy_wait this is susceptible to
longer-than-intended delays due to the impact of interrupt handling.

Fixes #11626

Signed-off-by: Peter A. Bigot [email protected]

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[carlescufi]

Thanks for this PR!
Since nrfx is part of Zephyr, is there a chance you could use the copy that already exists instead of copying it into soc.c?

[pabigot]

No; it comes from the soc subdirectory which isn't part of Zephyr.

[anangl]

Since nrfx is part of Zephyr, is there a chance you could use the copy that already exists instead of copying it into soc.c?

No; it comes from the soc subdirectory which isn't part of Zephyr.

We should make it part of Zephyr then.
The file (soc/nrfx_coredep.h) was not yet imported to Zephyr because so far there was no such need. Apparently, now such a need arose. I created a corresponding PR with this import, see #11644.

[anangl]

The added z_arch_busy_wait functions should call nrfx_coredep_delay_us (once it is imported to Zephyr) instead of copying its content.

[pabigot]

@anangl Requested modifications have been made.

[anangl]

Thank you for providing this PR and fixing the issue!