embassy_stm32/eth: support compliance testing

This change adds the possibility to perform compliance testing with
STM32 systems by directly exposing SMI when needed. Users can
then use this to configure PHY registers for test modes.

embassy-stm32/src/eth/mod.rs

@@ -177,6 +177,20 @@ pub unsafe trait PHY {
     fn poll_link<S: StationManagement>(&mut self, sm: &mut S, cx: &mut Context) -> bool;
 }
 
+impl<'d, T: Instance, P: PHY> Ethernet<'d, T, P> {
+    /// Directly expose the SMI interface used by the Ethernet driver.
+    ///
+    /// This can be used to for example configure special PHY registers for compliance testing.
+    ///
+    /// # Safety
+    ///
+    /// Revert any temporary PHY register changes such as to enable test modes before handing
+    /// the Ethernet device over to the networking stack otherwise things likely won't work.
+    pub unsafe fn station_management(&mut self) -> &mut impl StationManagement {
+        &mut self.station_management
+    }
+}
+
 trait SealedInstance {
     fn regs() -> crate::pac::eth::Eth;
 }

examples/stm32f4/src/bin/eth_compliance_test.rs

@@ -0,0 +1,77 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::eth::generic_smi::GenericSMI;
+use embassy_stm32::eth::{Ethernet, PacketQueue, StationManagement};
+use embassy_stm32::time::Hertz;
+use embassy_stm32::{bind_interrupts, eth, peripherals, rng, Config};
+use embassy_time::Timer;
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    ETH => eth::InterruptHandler;
+    HASH_RNG => rng::InterruptHandler<peripherals::RNG>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    let mut config = Config::default();
+    {
+        use embassy_stm32::rcc::*;
+        config.rcc.hse = Some(Hse {
+            freq: Hertz(8_000_000),
+            mode: HseMode::Bypass,
+        });
+        config.rcc.pll_src = PllSource::HSE;
+        config.rcc.pll = Some(Pll {
+            prediv: PllPreDiv::DIV4,
+            mul: PllMul::MUL180,
+            divp: Some(PllPDiv::DIV2), // 8mhz / 4 * 180 / 2 = 180Mhz.
+            divq: None,
+            divr: None,
+        });
+        config.rcc.ahb_pre = AHBPrescaler::DIV1;
+        config.rcc.apb1_pre = APBPrescaler::DIV4;
+        config.rcc.apb2_pre = APBPrescaler::DIV2;
+        config.rcc.sys = Sysclk::PLL1_P;
+    }
+    let p = embassy_stm32::init(config);
+
+    info!("Hello Compliance World!");
+
+    let mac_addr = [0x00, 0x00, 0xDE, 0xAD, 0xBE, 0xEF];
+
+    const PHY_ADDR: u8 = 0;
+    static PACKETS: StaticCell<PacketQueue<4, 4>> = StaticCell::new();
+    let mut device = Ethernet::new(
+        PACKETS.init(PacketQueue::<4, 4>::new()),
+        p.ETH,
+        Irqs,
+        p.PA1,
+        p.PA2,
+        p.PC1,
+        p.PA7,
+        p.PC4,
+        p.PC5,
+        p.PG13,
+        p.PB13,
+        p.PG11,
+        GenericSMI::new(PHY_ADDR),
+        mac_addr,
+    );
+
+    let sm = unsafe { device.station_management() };
+
+    // Just an example. Exact register settings depend on the specific PHY and test.
+    sm.smi_write(PHY_ADDR, 0, 0x2100);
+    sm.smi_write(PHY_ADDR, 11, 0xA000);
+
+    // NB: Remember to reset the PHY after testing before starting the networking stack
+
+    loop {
+        Timer::after_secs(1).await;
+    }
+}