[cc20rng] Revamping the ChaCha20 seeding

- chacha20_prng_block() uses counter in the state struct

- chacha20_setup() replaces chacha20_prng_reseed() and fills the whole
  state struct, fixing a bug where only half of the key was being set;
  as a result of 'counter' being set, a state struct filled with
  entropy from the TRNG makes reseeding occur after a random number of
  rounds instead of after a fixed 2^32-1 rounds

- decrementing of the block counter is done in chacha20_prng_block()

- chacha output is copied to buf _after_ the interrupt driven
  transmission of buf to UART has finished, to stop the race between
  reading and refilling of buf

1 files changed, 0 insertions, 2 deletions

diff --git a/src/cc20rng/stm32f4xx_it.h b/src/cc20rng/stm32f4xx_it.h
index 04c5a36..6edba3c 100644
--- a/src/cc20rng/stm32f4xx_it.h
+++ b/src/cc20rng/stm32f4xx_it.h
@@ -44,8 +44,6 @@
 #endif
 
 /* Includes ------------------------------------------------------------------*/
-#include "main.h"
-
 /* Exported types ------------------------------------------------------------*/
 /* Exported constants --------------------------------------------------------*/
 /* Exported macro ------------------------------------------------------------*/