Previously a value of 0 was used for the RSSI to signal that this value is not
present in `gnrc_netif_hdr_t`. However, an RSSI of 0 dBm is legal and even very
plausible data.
This commit defines `GNRC_NETIF_HDR_NO_RSSI` as `INT16_MIN`, which is below the
noise floor in the vacuum of outer space and hence impossible to receive.
For consistency, also GNRC_NETIF_HDR_NO_LQI is defined.
The logic used to check whether the RX timestamp was provided in the GNRC
implementation of `sock_ip_recv_buf_aux()` is incorrect: It still uses in-band
signalling via a timestamp of zero, but a dedicated flag was added to allow for
timestamps of zero.
Additionally, it is not necessary to check if a bit is set only to clear it -
clearing it unconditionally is faster and smaller.
When dumping memory the printed addresses always start with `00000000`.
This can be very confusing and lead to errors.
Allow the user to specify a starting address of the printed memory that
will be used instead.
By introducing a wrapper function, existing users are unaffected.
Disabling IRQs during malloc() provides mutually exclusive access and even is
safe from IRQ context, but is suboptimal for real time scenarios. Instead, the
implementation is changed to use a mutex to provide mutually exclusive access.
As a result, calls to malloc() and free() from IRQ context no longer is
possible. But this this is a really horrible idea to begin with, the impact
should be minimal and the improved real time properties of the system should
make it a good trade-off. An assert() is added to allow easy detection of
regressions and, hence, aid users to fix their code.
Split out Gunar Schorcht's clever approach to provide thread safe malloc for
AVR into a system module and make AVR depend on this. This allows other
platforms to also use this.
This adds compile-time options to configure the serial of an USB
peripheral. The serial be autogenerated with a configured number of
bytes. It is also possible to configure a fixed serial string for a
device and disable the autogeneration of the serial.
Update the `atomic_fetch_<OPERATION>_u<WIDTH>()` functions to return the old
value the target contained prior to applying the operation. This makes this
API much more versatile and closer to C11 atomics.
