3 files changed, 238 insertions, 0 deletions

diff --git a/embassy-stm32/src/eth/sma/mod.rs b/embassy-stm32/src/eth/sma/mod.rs
new file mode 100644
index 000000000..6c851911d
--- /dev/null
+++ b/embassy-stm32/src/eth/sma/mod.rs
@@ -0,0 +1,42 @@
+//! Station Management Agent (also known as MDIO or SMI).
+
+#![macro_use]
+
+#[cfg_attr(eth_v2, path = "v2.rs")]
+#[cfg_attr(any(eth_v1a, eth_v1b, eth_v1c), path = "v1.rs")]
+mod _version;
+
+use embassy_hal_internal::PeripheralType;
+use stm32_metapac::common::{RW, Reg};
+
+pub use self::_version::*;
+
+/// Station Management Interface (SMI).
+pub trait StationManagement {
+    /// Read a register over SMI.
+    fn smi_read(&mut self, phy_addr: u8, reg: u8) -> u16;
+    /// Write a register over SMI.
+    fn smi_write(&mut self, phy_addr: u8, reg: u8, val: u16);
+}
+
+trait SealedInstance {
+    fn regs() -> (Reg<AddressRegister, RW>, Reg<DataRegister, RW>);
+}
+
+/// MDIO instance.
+#[allow(private_bounds)]
+pub trait Instance: SealedInstance + PeripheralType + Send + 'static {}
+
+impl SealedInstance for crate::peripherals::ETH_SMA {
+    fn regs() -> (Reg<AddressRegister, RW>, Reg<DataRegister, RW>) {
+        let mac = crate::pac::ETH.ethernet_mac();
+
+        #[cfg(any(eth_v1a, eth_v1b, eth_v1c))]
+        return (mac.macmiiar(), mac.macmiidr());
+
+        #[cfg(eth_v2)]
+        return (mac.macmdioar(), mac.macmdiodr());
+    }
+}
+
+impl Instance for crate::peripherals::ETH_SMA {}
diff --git a/embassy-stm32/src/eth/sma/v1.rs b/embassy-stm32/src/eth/sma/v1.rs
new file mode 100644
index 000000000..db64a6c78
--- /dev/null
+++ b/embassy-stm32/src/eth/sma/v1.rs
@@ -0,0 +1,102 @@
+use embassy_hal_internal::Peri;
+pub(crate) use regs::{Macmiiar as AddressRegister, Macmiidr as DataRegister};
+use stm32_metapac::eth::regs;
+use stm32_metapac::eth::vals::{Cr, MbProgress, Mw};
+
+use super::{Instance, StationManagement};
+use crate::eth::{MDCPin, MDIOPin};
+use crate::gpio::{AfType, AnyPin, OutputType, SealedPin, Speed};
+
+/// Station Management Agent.
+///
+/// This peripheral is used for SMI reads and writes to the connected
+/// ethernet PHY/device(s).
+pub struct Sma<'d, T: Instance> {
+    _peri: Peri<'d, T>,
+    clock_range: Cr,
+    pins: [Peri<'d, AnyPin>; 2],
+}
+
+impl<'d, T: Instance> Sma<'d, T> {
+    /// Create a new instance of this peripheral.
+    pub fn new<#[cfg(afio)] A>(
+        peri: Peri<'d, T>,
+        mdio: Peri<'d, if_afio!(impl MDIOPin<T, A>)>,
+        mdc: Peri<'d, if_afio!(impl MDCPin<T, A>)>,
+    ) -> Self {
+        set_as_af!(mdio, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        set_as_af!(mdc, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+
+        // Enable necessary clocks.
+        critical_section::with(|_| {
+            #[cfg(eth_v1a)]
+            let reg = crate::pac::RCC.ahbenr();
+
+            #[cfg(any(eth_v1b, eth_v1c))]
+            let reg = crate::pac::RCC.ahb1enr();
+
+            reg.modify(|w| {
+                w.set_ethen(true);
+            })
+        });
+
+        let hclk = unsafe { crate::rcc::get_freqs().hclk1.to_hertz() };
+        let hclk = unwrap!(hclk, "SMA requires HCLK to be enabled, but it was not.");
+        let hclk_mhz = hclk.0 / 1_000_000;
+
+        // Set the MDC clock frequency in the range 1MHz - 2.5MHz
+        let clock_range = match hclk_mhz {
+            0..=24 => panic!("Invalid HCLK frequency - should be at least 25 MHz."),
+            25..=34 => Cr::CR_20_35,     // Divide by 16
+            35..=59 => Cr::CR_35_60,     // Divide by 26
+            60..=99 => Cr::CR_60_100,    // Divide by 42
+            100..=149 => Cr::CR_100_150, // Divide by 62
+            150..=216 => Cr::CR_150_168, // Divide by 102
+            _ => {
+                panic!("HCLK results in MDC clock > 2.5MHz even for the highest CSR clock divider")
+            }
+        };
+
+        Self {
+            _peri: peri,
+            clock_range,
+            pins: [mdio.into(), mdc.into()],
+        }
+    }
+}
+
+impl<T: Instance> StationManagement for Sma<'_, T> {
+    fn smi_read(&mut self, phy_addr: u8, reg: u8) -> u16 {
+        let (macmiiar, macmiidr) = T::regs();
+
+        macmiiar.modify(|w| {
+            w.set_pa(phy_addr);
+            w.set_mr(reg);
+            w.set_mw(Mw::READ); // read operation
+            w.set_cr(self.clock_range);
+            w.set_mb(MbProgress::BUSY); // indicate that operation is in progress
+        });
+        while macmiiar.read().mb() == MbProgress::BUSY {}
+        macmiidr.read().md()
+    }
+
+    fn smi_write(&mut self, phy_addr: u8, reg: u8, val: u16) {
+        let (macmiiar, macmiidr) = T::regs();
+
+        macmiidr.write(|w| w.set_md(val));
+        macmiiar.modify(|w| {
+            w.set_pa(phy_addr);
+            w.set_mr(reg);
+            w.set_mw(Mw::WRITE); // write
+            w.set_cr(self.clock_range);
+            w.set_mb(MbProgress::BUSY);
+        });
+        while macmiiar.read().mb() == MbProgress::BUSY {}
+    }
+}
+
+impl<T: Instance> Drop for Sma<'_, T> {
+    fn drop(&mut self) {
+        self.pins.iter_mut().for_each(|p| p.set_as_disconnected());
+    }
+}
diff --git a/embassy-stm32/src/eth/sma/v2.rs b/embassy-stm32/src/eth/sma/v2.rs
new file mode 100644
index 000000000..6bc5230b5
--- /dev/null
+++ b/embassy-stm32/src/eth/sma/v2.rs
@@ -0,0 +1,94 @@
+use embassy_hal_internal::Peri;
+pub(crate) use regs::{Macmdioar as AddressRegister, Macmdiodr as DataRegister};
+use stm32_metapac::eth::regs;
+
+use super::{Instance, StationManagement};
+use crate::eth::{MDCPin, MDIOPin};
+use crate::gpio::{AfType, AnyPin, OutputType, SealedPin, Speed};
+
+/// Station Management Agent.
+///
+/// This peripheral is used for SMI reads and writes to the connected
+/// ethernet PHY/device(s).
+pub struct Sma<'d, T: Instance> {
+    _peri: Peri<'d, T>,
+    pins: [Peri<'d, AnyPin>; 2],
+    clock_range: u8,
+}
+
+impl<'d, T: Instance> Sma<'d, T> {
+    /// Create a new instance of this peripheral.
+    pub fn new(peri: Peri<'d, T>, mdio: Peri<'d, impl MDIOPin<T>>, mdc: Peri<'d, impl MDCPin<T>>) -> Self {
+        set_as_af!(mdio, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+        set_as_af!(mdc, AfType::output(OutputType::PushPull, Speed::VeryHigh));
+
+        // Enable necessary clocks.
+        critical_section::with(|_| {
+            crate::pac::RCC.ahb1enr().modify(|w| {
+                w.set_ethen(true);
+            })
+        });
+
+        let hclk = unsafe { crate::rcc::get_freqs().hclk1.to_hertz() };
+        let hclk = unwrap!(hclk, "SMA requires HCLK to be enabled, but it was not.");
+        let hclk_mhz = hclk.0 / 1_000_000;
+
+        // Set the MDC clock frequency in the range 1MHz - 2.5MHz
+        let clock_range = match hclk_mhz {
+            0..=34 => 2,    // Divide by 16
+            35..=59 => 3,   // Divide by 26
+            60..=99 => 0,   // Divide by 42
+            100..=149 => 1, // Divide by 62
+            150..=249 => 4, // Divide by 102
+            250..=310 => 5, // Divide by 124
+            _ => {
+                panic!("HCLK results in MDC clock > 2.5MHz even for the highest CSR clock divider")
+            }
+        };
+
+        Self {
+            _peri: peri,
+            clock_range,
+            pins: [mdio.into(), mdc.into()],
+        }
+    }
+}
+
+impl<T: Instance> StationManagement for Sma<'_, T> {
+    fn smi_read(&mut self, phy_addr: u8, reg: u8) -> u16 {
+        let (macmdioar, macmdiodr) = T::regs();
+
+        macmdioar.modify(|w| {
+            w.set_pa(phy_addr);
+            w.set_rda(reg);
+            w.set_goc(0b11); // read
+            w.set_cr(self.clock_range);
+            w.set_mb(true);
+        });
+
+        while macmdioar.read().mb() {}
+
+        macmdiodr.read().md()
+    }
+
+    fn smi_write(&mut self, phy_addr: u8, reg: u8, val: u16) {
+        let (macmdioar, macmdiodr) = T::regs();
+
+        macmdiodr.write(|w| w.set_md(val));
+        macmdioar.modify(|w| {
+            w.set_pa(phy_addr);
+            w.set_rda(reg);
+            w.set_goc(0b01); // write
+            w.set_cr(self.clock_range);
+            w.set_mb(true);
+        });
+
+        while macmdioar.read().mb() {}
+    }
+}
+
+impl<T: Instance> Drop for Sma<'_, T> {
+    fn drop(&mut self) {
+        self.pins.iter_mut().for_each(|p| p.set_as_disconnected());
+    }
+}