While attempting to create architecture-specific implementation
of up_udelay, it was discovered that the overriding function is not
included in the final binary, the weak implementation was used instead.
Further investigation and experimentation showed that the linker
only overrides the weak implementation with the custom one if
the custom one is present in a .c source file that contains at least
one other function that is called from somewhere. Some additional
testing revealed that at least one other already present up_udelay
override (rv32m1-vega:nsh) is affected by this.
In a short mailing list discussion it was determined that this
is a likely result of using static libraries during the build process
and it was suggested to introduce configuration option that will
exclude weak implementations of the function from the build altogether.
This patch does that.
This patch does not enable this configuration option for any existing
board/chip because doing so would change its behaviour and needs
to be tested by users of the hardware.
Also changed is the static assertion in sched/clock/clock_delay.c
to not prevent building the code when architecture declares that
it does not use BOARD_LOOPSPERMSEC to determine required loop count.
BOARD_LOOPSPERMSEC is made undefined in such case.
Patch was tested by building breadxavr:nsh (identical binary by SHA256),
rv32m1-vega:nsh (identical text section) and rv-virt:nsh (text section
differs because of different ordering of functions in the binary, ostest
passed though.)
Signed-off-by: Kerogit <kr.git@kerogit.eu>
Changes the default value for CONFIG_BOARD_LOOPSPERMSEC to -1, which is
invalid. All boards that forget to configure this value will encounter a
static assertion at compile time, enforcing that configurations
upstreamed to NuttX have calibrated values for correct delay timings.
Boards which implement ALARM_ARCH or TIMER_ARCH do not rely on the
busy-loop delay implementation and thus only have a run-time check to
ensure proper delay-timings (in the case where delays are used before
the alarm/timer driver is registered).
Some boards already in the NuttX upstream do not have calibrated values,
but there are no users who currently own the board to submit a
calibrated value for the configurations to use. In this scenario, the
value is temporarily set to 0 and a warning is displayed so that users
of these boards are informed of the calibration process.
Signed-off-by: Matteo Golin <matteo.golin@gmail.com>
