Add a general purpose random number generator via pico_rand library. which tries to use as much real entropy as possible mixed into a PRNG
Co-authored-by: graham sanderson <graham.sanderson@raspberrypi.com>
* Extract all poll/threadsafe_background/freertos from cyw43_arch into new abstraction async_context:
* provides support for asynchronous events (timers/IRQ notifications) to be handled in a safe context.
* now guarantees all callbacks happen on a single core.
* is reusable by multiple different libraries (stdio_usb can now be ported to this but hasn't been yet).
* supports multiple independent instances (independent instances will not block each other).
* cyw43_arch libraries cleaned up to use the new abstraction. Note each distinct cyw43_arch type is now a very thin layer that creates the right type of context and adds cyw43_driver and lwip support as appropriate.
Additionally,
* Add new pico_time and hardware_alarm APIs
* Add from_us_since_boot()
* Add alarm_pool_create_with_unused_hardware_alarm()
* Add alarm_pool_add_alarm_at_force_in_context()
* Add hardware_alarm_claim_unused()
* Add hardware_alarm_force_irq()
* Added panic_compact() and some minor comment cleanup; moved FIRST_USER_IRQ define to platform_defs.h
* Add mbedtls as a submodule
Checked out on branch mbedtls-2.28
* Add mbedtls to pico-sdk
Link your code to pico_lwip_mbedtls and pico_mbedtls.
See tls_client example in pico-examples
Fixes https://github.com/raspberrypi/pico-sdk/issues/893
Adds a new cmsis_core INTERFACE library, which provides the basic CMSIS macros/definitions, and RP2040.h and system_RP2040.h
By default the isr_ methods in the vector table are renamed to their CMSIS versions, but this can be overridden by defining PICO_CMSIS_RENAME_EXCEPTIONS=0
* Add pico_bootsel_via_double_reset library, fix#87
* pico_bootsel_via_double_reset: remove unnecessary library guard, fix subdirectory ordering
* Fix C type used as PICO_CONFIG type
