board: enable random/entropy generators if BT

BT uses PSA Crypto API to perform crypto operations and, on this
platform, these APIs are implemented through Mbed TLS. In order
to properly initialize this library, a random number generator
is required.

* If the platform supports an HW entropy generator (ex: native_sim,
  nrf), then ENTROPY_GENERATOR must be used;
* Otherwise (ex: qemu_cortex_m3) test random generator can be
  enabled.

Enabling the proper option at board Kconfig level allows for
a more compact code change instead of manually editing _all_
the samples/tests that required this fix.

Signed-off-by: Valerio Setti <vsetti@baylibre.com>

boards/native/native_sim/Kconfig.defconfig

@@ -32,5 +32,14 @@ config UART_CONSOLE
 
 endif # CONSOLE
 
+# BT relies on PSA Crypto API to perform crypto operations. On this platform
+# this is implemented by Mbed TLS which requires a (possibly true) random
+# number generator to initialize properly. We enable ENTROPY_GENERATOR here
+# instead of manually adding it to all samples/tests configuration files because
+# it looks more compact and easier to maintain.
+config ENTROPY_GENERATOR
+	bool
+	default y if BT
+
 
 endif # BOARD_NATIVE_SIM

boards/native/nrf_bsim/Kconfig.defconfig

@@ -58,6 +58,19 @@ config BT_HCI_IPC
 
 endif # BOARD_NRF5340BSIM_NRF5340_CPUAPP
 
+if BOARD_NRF5340BSIM_NRF5340_CPUAPP || BOARD_NRF52_BSIM
+
+# BT relies on PSA Crypto API to perform crypto operations. On this platform
+# this is implemented by Mbed TLS which requires a (possibly true) random
+# number generator to initialize properly. We enable ENTROPY_GENERATOR here
+# instead of manually adding it to all samples/tests configuration files because
+# it looks more compact and easier to maintain.
+config ENTROPY_GENERATOR
+	bool
+	default y if BT
+
+endif # BOARD_NRF5340BSIM_NRF5340_CPUAPP || BOARD_NRF52_BSIM
+
 # The 15.4 driver Tx encryption is currently not functional with this
 # simulated board => we disable it by default. With this Openthread will normally
 # default to encrypt packets on its own.

boards/nordic/nrf5340_audio_dk/Kconfig.defconfig

@@ -53,6 +53,19 @@ config FLASH_LOAD_SIZE
 
 endif # BOARD_NRF5340_AUDIO_DK_NRF5340_CPUAPP_NS
 
+if BOARD_NRF5340_AUDIO_DK_NRF5340_CPUAPP
+
+# BT relies on PSA Crypto API to perform crypto operations. On this platform
+# this is implemented by Mbed TLS which requires a (possibly true) random
+# number generator to initialize properly. We enable ENTROPY_GENERATOR here
+# instead of manually adding it to all samples/tests configuration files because
+# it looks more compact and easier to maintain.
+config ENTROPY_GENERATOR
+	bool
+	default y if BT
+
+endif # BOARD_NRF5340_AUDIO_DK_NRF5340_CPUAPP
+
 config BT_HCI_IPC
 	default y if BT
 

boards/nordic/nrf5340dk/Kconfig.defconfig

@@ -43,6 +43,19 @@ config SRAM_SIZE
 
 endif # BOARD_NRF5340DK_NRF5340_CPUAPP && TRUSTED_EXECUTION_SECURE
 
+if BOARD_NRF5340DK_NRF5340_CPUAPP
+
+# BT relies on PSA Crypto API to perform crypto operations. On this platform
+# this is implemented by Mbed TLS which requires a (possibly true) random
+# number generator to initialize properly. We enable ENTROPY_GENERATOR here
+# instead of manually adding it to all samples/tests configuration files because
+# it looks more compact and easier to maintain.
+config ENTROPY_GENERATOR
+	bool
+	default y if BT
+
+endif # BOARD_NRF5340DK_NRF5340_CPUAPP
+
 if BOARD_NRF5340DK_NRF5340_CPUAPP_NS
 
 config FLASH_LOAD_OFFSET

boards/qemu/cortex_m3/Kconfig.defconfig

@@ -12,4 +12,12 @@ choice NULL_POINTER_EXCEPTION_DETECTION
 	default NULL_POINTER_EXCEPTION_DETECTION_NONE
 endchoice
 
+# BT relies on PSA Crypto API to perform crypto operations and, on this platform,
+# these APIs are provided thougth Mbed TLS. Unfortunately this platform is not
+# provided with a true random number generator which is required to properly
+# initialize the PSA Crypto core, so we need to enable the fake TEST_RANDOM_GENERATOR.
+config TEST_RANDOM_GENERATOR
+	bool
+	default y if BT
+
 endif # BOARD_QEMU_CORTEX_M3