To control the log level and the format of the log output of SDK libraries, a bunch of library-specific printf functions are realized which map the log output from SDK libraries to RIOT's log macros.
Log outputs generated by binary ESP32 SDK libraries are mapped to the ESP32's log module which supports colored and tagged log outpus. Tagged log outputs from SDK libraries are handled accordingly.
Renames crypto functions of ESP32 SDK in vendor code to resolve the conflicts between `wpa-supplicant` crypto functions and RIOT's `crypto` and `hashes` modules.
To resolve the conflicts between `wpa-supplicant` crypto functions (part of the ESP32 SDK) and RIOT's `crypto` and `hashes` modules, the crypto function headers from ESP32 SDK are added to vendor code and the crypto functions are renamed using the prefix `wpa_`.
Initializing the stdio file descriptors in global reent structure with newlib fake stdio file descriptors led to the problem that newlib stdio functions printf and puts were not working since they can't operate on these fake stdio file descriptors. Therefore, this initialization was removed. Now, the real stdio file descriptors as created automatically by newlib are used. Specific functions `printf`, `puts`, `getchar`and `putchar` are not required any longer and are removed now.
Some ESP32 boards (like my SparkFun ESP32 Thing) have a main clock
crystal that runs at 26MHz, not 40MHz. RIOT appears to assume 40MHz.
The mismatch causes the UART to not sync properly, resulting in
garbage written to the terminal instead of log output.
I’ve added:
* A new board configuration constant ESP32_XTAL_FREQ that defaults
to 40, but can be overridden by a board def or at build time to
force a specific value (i.e. 26).
* Some code spliced into system_clk_init() to check this constant and
call rtc_clk_init() to set the correct frequency.
* A copy of the rtf_clk_init() function from the ESP-IDF sources.
Fixes#10272
