RngCore trait is implemented (esp-rs#1122)

* WIP

made randomness ensuring function
implemented RngCore trait (final version i guess)

* Revert part of changes and leave TODO comment

Changelog entry

Get rid of warning

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - ESP32-P4: Add efuse reading support (#1114)
 
 - Allow for splitting of the USB Serial JTAG peripheral into tx/rx components (#1024)
+- `RngCore` trait is implemented (#1122)
 
 ### Fixed
 

esp-hal-common/Cargo.toml

@@ -38,6 +38,7 @@ procmacros           = { version = "0.8.0", features = ["enum-dispatch", "ram"],
 strum                = { version = "0.25.0", default-features = false, features = ["derive"] }
 void                 = { version = "1.0.2", default-features = false }
 usb-device           = { version = "0.3.1", optional = true }
+rand_core            = { version = "0.6.4" }
 
 # async
 embedded-hal-async   = { version = "1.0.0", optional = true }

esp-hal-common/src/rng.rs

@@ -65,6 +65,8 @@
 
 use core::{convert::Infallible, marker::PhantomData};
 
+use rand_core::RngCore;
+
 use crate::{peripheral::Peripheral, peripherals::RNG};
 
 /// Random number generator driver
@@ -104,3 +106,35 @@ impl embedded_hal::blocking::rng::Read for Rng {
         Ok(())
     }
 }
+
+// TODO: CryptoRng trait will be implemented when true randomness of RNG is
+// ensured
+
+impl RngCore for Rng {
+    fn next_u32(&mut self) -> u32 {
+        // Directly use the existing random method to get a u32 random number
+        self.random()
+    }
+
+    fn next_u64(&mut self) -> u64 {
+        // Call random() twice to generate a u64 random number (сombine two u32)
+        let upper = self.random() as u64;
+        let lower = self.random() as u64;
+        (upper << 32) | lower
+    }
+
+    fn fill_bytes(&mut self, dest: &mut [u8]) {
+        // Fill the destination buffer with random bytes
+        for chunk in dest.chunks_mut(4) {
+            let rand_bytes = self.random().to_le_bytes();
+            for (dest_byte, rand_byte) in chunk.iter_mut().zip(&rand_bytes) {
+                *dest_byte = *rand_byte;
+            }
+        }
+    }
+
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand_core::Error> {
+        // Similar implementation as fill_bytes, but encapsulated in a Result
+        Ok(self.fill_bytes(dest))
+    }
+}

esp32h2-hal/Cargo.toml

@@ -51,6 +51,7 @@ sha2               = { version = "0.10.8", default-features = false}
 smart-leds         = "0.4.0"
 ssd1306            = "0.8.4"
 static_cell        = { version = "2.0.0", features = ["nightly"] }
+rand_core          = "0.6.4"
 
 [features]
 default = ["embassy-integrated-timers", "rt", "vectored", "zero-rtc-bss"]