feat: hwrng for stm32 & rp (#413)

Cargo.toml

@@ -48,7 +48,7 @@ cortex-m-semihosting = { version = "0.5" }
 critical-section = { version = "1.1.2" }
 # Disabling default features may reduce the code size by not providing atomics
 # for types larger than the pointer width, which we do not use.
-portable-atomic = { version = "1.6.0", default-features = false, features = [
+portable-atomic = { version = "1.7.0", default-features = false, features = [
   "require-cas",
 ] }
 
@@ -92,7 +92,7 @@ document-features = "0.2.8"
 heapless = { version = "0.8.0", default-features = false }
 konst = { version = "0.3.8", default-features = false }
 ld-memory = { version = "0.2.9" }
-once_cell = { version = "1.19.0", default-features = false, features = [
+once_cell = { version = "=1.19.0", default-features = false, features = [
   "critical-section",
 ] }
 paste = { version = "1.0" }

book/src/support_matrix.html

@@ -4,7 +4,7 @@
     <tr>
       <th>Chip</th>
       <th>Testing Board</th>
-      <th colspan="6">Functionality</th>
+      <th colspan="7">Functionality</th>
     </tr>
     <tr>
       <th></th>
@@ -15,6 +15,7 @@
       <th>User USB</th>
       <th>Wi-Fi</th>
       <th>Ethernet over USB</th>
+      <th>Hardware Random Number Generator</th>
     </tr>
   </thead>
   <tbody>
@@ -27,6 +28,7 @@
       <td class="support-cell" title="available in hardware, but not currently supported by RIOT-rs">❌</td>
       <td class="support-cell" title="supported with some caveats">☑️</td>
       <td class="support-cell" title="available in hardware, but not currently supported by RIOT-rs">❌</td>
+      <td class="support-cell" title="available in hardware, but not currently supported by RIOT-rs">❌</td>
     </tr>
     <tr>
       <td>nRF52xxx</td>
@@ -37,6 +39,7 @@
       <td class="support-cell" title="supported">✅</td>
       <td class="support-cell" title="not available on this piece of hardware">–</td>
       <td class="support-cell" title="supported">✅</td>
+      <td class="support-cell" title="supported">✅</td>
     </tr>
     <tr>
       <td>nRF53xx</td>
@@ -47,6 +50,7 @@
       <td class="support-cell" title="supported">✅</td>
       <td class="support-cell" title="not available on this piece of hardware">–</td>
       <td class="support-cell" title="supported">✅</td>
+      <td class="support-cell" title="supported">✅</td>
     </tr>
     <tr>
       <td>RP2040</td>
@@ -57,6 +61,7 @@
       <td class="support-cell" title="supported">✅</td>
       <td class="support-cell" title="not available on this piece of hardware">–</td>
       <td class="support-cell" title="supported">✅</td>
+      <td class="support-cell" title="supported">✅</td>
     </tr>
     <tr>
       <td>RP2040</td>
@@ -67,6 +72,7 @@
       <td class="support-cell" title="supported">✅</td>
       <td class="support-cell" title="supported">✅</td>
       <td class="support-cell" title="supported">✅</td>
+      <td class="support-cell" title="supported">✅</td>
     </tr>
     <tr>
       <td>STM32F401RETX</td>
@@ -77,6 +83,7 @@
       <td class="support-cell" title="not available on this piece of hardware">–</td>
       <td class="support-cell" title="not available on this piece of hardware">–</td>
       <td class="support-cell" title="not available on this piece of hardware">–</td>
+      <td class="support-cell" title="not available on this piece of hardware">–</td>
     </tr>
     <tr>
       <td>STM32F755ZITX</td>
@@ -87,6 +94,7 @@
       <td class="support-cell" title="supported">✅</td>
       <td class="support-cell" title="not available on this piece of hardware">–</td>
       <td class="support-cell" title="available in hardware, but not currently supported by RIOT-rs">❌</td>
+      <td class="support-cell" title="supported">✅</td>
     </tr>
     <tr>
       <td>STM32W55RGVX</td>
@@ -97,6 +105,7 @@
       <td class="support-cell" title="supported">✅</td>
       <td class="support-cell" title="not available on this piece of hardware">–</td>
       <td class="support-cell" title="supported">✅</td>
+      <td class="support-cell" title="supported">✅</td>
     </tr>
   </tbody>
 </table>

doc/support_matrix.yml

@@ -35,6 +35,9 @@ functionalities:
   - name: ethernet_over_usb
     title: Ethernet over USB
     description:
+  - name: hwrng
+    title: Hardware Random Number Generator
+    description:
 
 # Encodes support status for each chip.
 chips:
@@ -43,6 +46,7 @@ chips:
     support:
       gpio: supported
       debug_output: supported
+      hwrng: supported
       logging: supported
       wifi: not_available
 
@@ -51,6 +55,7 @@ chips:
     support:
       gpio: supported
       debug_output: supported
+      hwrng: supported
       logging: supported
       wifi: not_available
 
@@ -59,6 +64,7 @@ chips:
     support:
       gpio: supported
       debug_output: supported
+      hwrng: supported
       logging: supported
       wifi: not_available
 
@@ -67,6 +73,7 @@ chips:
     support:
       gpio: supported
       debug_output: supported
+      hwrng: not_currently_supported
       logging: supported
       wifi: not_available
 
@@ -75,6 +82,7 @@ chips:
     support:
       gpio: supported
       debug_output: supported
+      hwrng: not_available
       logging: supported
       wifi: not_available
 
@@ -83,6 +91,7 @@ chips:
     support:
       gpio: supported
       debug_output: supported
+      hwrng: supported
       logging: supported
       wifi: not_available
 
@@ -91,6 +100,7 @@ chips:
     support:
       gpio: supported
       debug_output: supported
+      hwrng: supported
       logging: supported
       wifi: not_available
 

examples/coap/laze.yml

@@ -8,3 +8,6 @@ apps:
       - ?release
       - network
       - random
+    conflicts:
+      # see https://github.com/future-proof-iot/RIOT-rs/issues/418
+      - thumbv6m-none-eabi

laze-project.yml

@@ -602,6 +602,9 @@ modules:
       # doesn't have an entry in the cfg(feature = "hwrng") part of init_task
       - nrf51
       - nrf52
+      - rp
+      - stm32h755zitx
+      - stm32wb55rgvx
     env:
       global:
         FEATURES:

src/riot-rs-boards/st-nucleo-h755zi-q/Cargo.toml

@@ -12,5 +12,8 @@ embassy-stm32 = { workspace = true, features = [
 ] }
 riot-rs-debug = { workspace = true, features = ["rtt-target"] }
 riot-rs-rt.workspace = true
-riot-rs-stm32 = { workspace = true, features = ["stm32-usb-synopsis"] }
+riot-rs-stm32 = { workspace = true, features = [
+  "stm32-hash-rng",
+  "stm32-usb-synopsis",
+] }
 stm32 = { path = "../../riot-rs-chips/stm32" }

src/riot-rs-boards/st-nucleo-wb55/Cargo.toml

@@ -9,5 +9,5 @@ edition = "2021"
 [dependencies]
 embassy-stm32 = { workspace = true, features = ["stm32wb55rg"] }
 riot-rs-debug = { workspace = true, features = ["rtt-target"] }
-riot-rs-stm32 = { workspace = true, features = ["stm32-usb"] }
+riot-rs-stm32 = { workspace = true, features = ["stm32-rng", "stm32-usb"] }
 riot-rs-rt.workspace = true

src/riot-rs-embassy/Cargo.toml

@@ -77,7 +77,7 @@ usb = [
 net = ["dep:embassy-net", "time"]
 usb-ethernet = ["usb", "net"]
 ## Use a hardware RNG to seed into the riot-rs-random system-wide RNG
-hwrng = ["riot-rs-nrf/hwrng"]
+hwrng = ["riot-rs-nrf/hwrng", "riot-rs-rp/hwrng", "riot-rs-stm32/hwrng"]
 
 wifi = []
 wifi-cyw43 = ["riot-rs-rp/wifi-cyw43", "net", "wifi"]

src/riot-rs-rp/Cargo.toml

@@ -19,6 +19,7 @@ embassy-rp = { workspace = true, default-features = false, features = [
 ] }
 riot-rs-debug = { workspace = true }
 riot-rs-embassy-common = { workspace = true }
+riot-rs-random = { workspace = true, optional = true }
 riot-rs-utils = { workspace = true }
 static_cell = { workspace = true, optional = true }
 
@@ -40,6 +41,9 @@ embassy-rp = { workspace = true, default-features = false, features = [
 ## Enables GPIO interrupt support.
 external-interrupts = ["riot-rs-embassy-common/external-interrupts"]
 
+## Enables seeding the random number generator from hardware.
+hwrng = ["dep:riot-rs-random"]
+
 ## Enables USB support.
 usb = []
 

src/riot-rs-rp/src/hwrng.rs

@@ -0,0 +1,3 @@
+pub fn construct_rng(_peripherals: &mut crate::OptionalPeripherals) {
+    riot_rs_random::construct_rng(embassy_rp::clocks::RoscRng);
+}

src/riot-rs-rp/src/lib.rs

@@ -16,6 +16,9 @@ mod wifi;
 #[cfg(feature = "wifi-cyw43")]
 pub mod cyw43;
 
+#[cfg(feature = "hwrng")]
+pub mod hwrng;
+
 #[cfg(feature = "usb")]
 pub mod usb;
 

src/riot-rs-stm32/Cargo.toml

@@ -15,8 +15,9 @@ embassy-executor = { workspace = true, default-features = false, features = [
   "arch-cortex-m",
 ] }
 embassy-stm32 = { workspace = true, default-features = false }
-riot-rs-embassy-common = { workspace = true }
 portable-atomic = { workspace = true }
+riot-rs-embassy-common = { workspace = true }
+riot-rs-random = { workspace = true, optional = true }
 static_cell = { workspace = true }
 
 [target.'cfg(context = "stm32")'.dependencies]
@@ -33,6 +34,13 @@ external-interrupts = [
   "riot-rs-embassy-common/external-interrupts",
 ]
 
+## Enables seeding the random number generator from hardware.
+hwrng = ["dep:riot-rs-random"]
+# These are chosen automatically by riot-rs-boards and select the correct stm32
+# rng peripheral support.
+stm32-hash-rng = []
+stm32-rng = []
+
 ## Enables USB support.
 usb = []
 # These are chosen automatically by riot-rs-boards and select the correct stm32

src/riot-rs-stm32/src/hwrng.rs

@@ -0,0 +1,36 @@
+use embassy_stm32::rng::Rng;
+use embassy_stm32::{bind_interrupts, peripherals, rng};
+
+#[cfg(not(any(feature = "stm32-hash-rng", feature = "stm32-rng")))]
+compile_error!("no stm32 rng feature enabled");
+
+#[cfg(feature = "stm32-hash-rng")]
+bind_interrupts!(struct Irqs {
+    HASH_RNG => rng::InterruptHandler<peripherals::RNG>;
+});
+
+#[cfg(feature = "stm32-rng")]
+bind_interrupts!(struct Irqs {
+    RNG => rng::InterruptHandler<peripherals::RNG>;
+});
+
+pub fn construct_rng(peripherals: &mut crate::OptionalPeripherals) {
+    cfg_if::cfg_if! {
+        // The union of all contexts that wind up in a construct_rng should be synchronized
+        // with laze-project.yml's hwrng module.
+        if #[cfg(any(context = "stm32"))] {
+            let rng = Rng::new(
+                peripherals
+                    .RNG
+                    // We don't even have to take it out, just use it to seed the RNG
+                    .as_mut()
+                    .expect("RNG has not been previously used"),
+                Irqs,
+            );
+
+            riot_rs_random::construct_rng(rng);
+        } else if #[cfg(context = "riot-rs")] {
+            compile_error!("hardware RNG is not supported on this architecture");
+        }
+    }
+}