Update third_party/libtock-drivers to support OpenSK.

third_party/libtock-drivers/src/rng.rs

@@ -1,9 +1,6 @@
-use crate::callback::Identity0Consumer;
-use crate::futures;
-use crate::result::TockResult;
-use crate::syscalls;
+use crate::util;
 use core::cell::Cell;
-use core::mem;
+use libtock_core::{callback, syscalls};
 
 const DRIVER_NUMBER: usize = 0x40001;
 
@@ -19,24 +16,30 @@ mod allow_nr {
     pub const SHARE_BUFFER: usize = 0;
 }
 
-#[non_exhaustive]
-pub struct RngDriver;
+pub fn fill_buffer(buf: &mut [u8]) -> bool {
+    let buf_len = buf.len();
 
-impl RngDriver {
-    pub async fn fill_buffer(&mut self, buf: &mut [u8]) -> TockResult<()> {
-        let buf_len = buf.len();
-        let shared_memory = syscalls::allow(DRIVER_NUMBER, allow_nr::SHARE_BUFFER, buf)?;
-        let is_filled = Cell::new(false);
-        let mut is_filled_alarm = || is_filled.set(true);
-        let subscription = syscalls::subscribe::<Identity0Consumer, _>(
-            DRIVER_NUMBER,
-            subscribe_nr::BUFFER_FILLED,
-            &mut is_filled_alarm,
-        )?;
-        syscalls::command(DRIVER_NUMBER, command_nr::REQUEST_RNG, buf_len, 0)?;
-        futures::wait_until(|| is_filled.get()).await;
-        mem::drop(subscription);
-        mem::drop(shared_memory);
-        Ok(())
+    let result = syscalls::allow(DRIVER_NUMBER, allow_nr::SHARE_BUFFER, buf);
+    if result.is_err() {
+        return false;
     }
+
+    let is_filled = Cell::new(false);
+    let mut is_filled_alarm = || is_filled.set(true);
+    let subscription = syscalls::subscribe::<callback::Identity0Consumer, _>(
+        DRIVER_NUMBER,
+        subscribe_nr::BUFFER_FILLED,
+        &mut is_filled_alarm,
+    );
+    if subscription.is_err() {
+        return false;
+    }
+
+    let result_code = syscalls::command(DRIVER_NUMBER, command_nr::REQUEST_RNG, buf_len, 0);
+    if result_code.is_err() {
+        return false;
+    }
+
+    util::yieldk_for(|| is_filled.get());
+    return true;
 }