Previously we used `gettimeofday()` for Mbed TLS timing, but its
implementation provided by Mbed OS is only precise to seconds. The
microsecond component of the output `struct timeval` is always set
to zero. But Mbed TLS requires millisecond precision.
To provide required timing precision, switch to use `LowPowerTicker`
or (microsecond) `Ticker`. `LowPowerTicker` is preferred as it saves
power and Mbed TLS does not require microsecond precision.
Don't attempt to use default_random_seed unless both PSA and Experimental API
support are enabled. This prevents errors when the Mbed TLS NV Seed feature is
being used on platforms that have PSA enabled by default, but not Experimental
API support by default.
[DEBUG] Output: compilation terminated.
[ERROR] In file included from ./mbed-os/connectivity/mbedtls/include/mbedtls/config.h:31,
from ./mbed-os/connectivity/mbedtls/include/mbedtls/entropy.h:28,
./mbed-os/connectivity/mbedtls/platform/inc/platform_mbed.h:26:10: fatal error: default_random_seed.h: No such file or directory
26 | #include "default_random_seed.h"
Lingkai Dong
Jaeden Amero
George Psimenos