From dc919c236d7ec7fe443b41cbaf3ad267fcacb7ca Mon Sep 17 00:00:00 2001
From: Bob McWhirter <bmcwhirt@redhat.com>
Date: Mon, 26 Apr 2021 09:43:19 -0400
Subject: [PATCH] Add an RNG trait.

---
 embassy-traits/src/lib.rs |  1 +
 embassy-traits/src/rng.rs | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)
 create mode 100644 embassy-traits/src/rng.rs

diff --git a/embassy-traits/src/lib.rs b/embassy-traits/src/lib.rs
index ea59444c1..1ce5dbe7e 100644
--- a/embassy-traits/src/lib.rs
+++ b/embassy-traits/src/lib.rs
@@ -14,3 +14,4 @@ pub mod gpio;
 pub mod i2c;
 pub mod spi;
 pub mod uart;
+pub mod rng;
diff --git a/embassy-traits/src/rng.rs b/embassy-traits/src/rng.rs
new file mode 100644
index 000000000..af786bd4a
--- /dev/null
+++ b/embassy-traits/src/rng.rs
@@ -0,0 +1,17 @@
+use core::future::Future;
+
+/// Random-number Generator
+pub trait Rng {
+    type Error;
+
+    type RngFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a
+    where
+        Self: 'a;
+
+    /// Completely fill the provided buffer with random bytes.
+    ///
+    /// May result in delays if entropy is exhausted prior to completely
+    /// filling the buffer. Upon completion, the buffer will be completely
+    /// filled or an error will have been reported.
+    fn fill<'a>(&'a mut self, dest: &'a mut [u8]) -> Self::RngFuture<'a>;
+}