eth: Add lan8742a PHY

3 files changed, 204 insertions, 20 deletions

diff --git a/embassy-stm32/src/eth/lan8742a.rs b/embassy-stm32/src/eth/lan8742a.rs
new file mode 100644
index 000000000..74d0ca5de
--- /dev/null
+++ b/embassy-stm32/src/eth/lan8742a.rs
@@ -0,0 +1,103 @@
+//! SMSC LAN8742A Ethernet PHY
+
+use super::{StationManagement, PHY};
+
+#[allow(dead_code)]
+mod phy_consts {
+    pub const PHY_REG_BCR: u8 = 0x00;
+    pub const PHY_REG_BSR: u8 = 0x01;
+    pub const PHY_REG_ID1: u8 = 0x02;
+    pub const PHY_REG_ID2: u8 = 0x03;
+    pub const PHY_REG_ANTX: u8 = 0x04;
+    pub const PHY_REG_ANRX: u8 = 0x05;
+    pub const PHY_REG_ANEXP: u8 = 0x06;
+    pub const PHY_REG_ANNPTX: u8 = 0x07;
+    pub const PHY_REG_ANNPRX: u8 = 0x08;
+    pub const PHY_REG_SSR: u8 = 0x1F; // Special Status Register
+    pub const PHY_REG_CTL: u8 = 0x0D; // Ethernet PHY Register Control
+    pub const PHY_REG_ADDAR: u8 = 0x0E; // Ethernet PHY Address or Data
+
+    pub const PHY_REG_WUCSR: u16 = 0x8010;
+
+    pub const PHY_REG_BCR_COLTEST: u16 = 1 << 7;
+    pub const PHY_REG_BCR_FD: u16 = 1 << 8;
+    pub const PHY_REG_BCR_ANRST: u16 = 1 << 9;
+    pub const PHY_REG_BCR_ISOLATE: u16 = 1 << 10;
+    pub const PHY_REG_BCR_POWERDN: u16 = 1 << 11;
+    pub const PHY_REG_BCR_AN: u16 = 1 << 12;
+    pub const PHY_REG_BCR_100M: u16 = 1 << 13;
+    pub const PHY_REG_BCR_LOOPBACK: u16 = 1 << 14;
+    pub const PHY_REG_BCR_RESET: u16 = 1 << 15;
+
+    pub const PHY_REG_BSR_JABBER: u16 = 1 << 1;
+    pub const PHY_REG_BSR_UP: u16 = 1 << 2;
+    pub const PHY_REG_BSR_FAULT: u16 = 1 << 4;
+    pub const PHY_REG_BSR_ANDONE: u16 = 1 << 5;
+
+    pub const PHY_REG_SSR_ANDONE: u16 = 1 << 12;
+    pub const PHY_REG_SSR_SPEED: u16 = 0b111 << 2;
+    pub const PHY_REG_SSR_10BASE_HD: u16 = 0b001 << 2;
+    pub const PHY_REG_SSR_10BASE_FD: u16 = 0b101 << 2;
+    pub const PHY_REG_SSR_100BASE_HD: u16 = 0b010 << 2;
+    pub const PHY_REG_SSR_100BASE_FD: u16 = 0b110 << 2;
+}
+use self::phy_consts::*;
+
+/// SMSC LAN8742A Ethernet PHY
+pub struct LAN8742A;
+
+unsafe impl PHY for LAN8742A {
+    /// Reset PHY and wait for it to come out of reset.
+    fn phy_reset<S: StationManagement>(sm: &mut S) {
+        sm.smi_write(PHY_REG_BCR, PHY_REG_BCR_RESET);
+        while sm.smi_read(PHY_REG_BCR) & PHY_REG_BCR_RESET == PHY_REG_BCR_RESET {}
+    }
+
+    /// PHY initialisation.
+    fn phy_init<S: StationManagement>(sm: &mut S) {
+        // Clear WU CSR
+        Self::smi_write_ext(sm, PHY_REG_WUCSR, 0);
+
+        // Enable auto-negotiation
+        sm.smi_write(
+            PHY_REG_BCR,
+            PHY_REG_BCR_AN | PHY_REG_BCR_ANRST | PHY_REG_BCR_100M,
+        );
+    }
+
+    fn poll_link<S: StationManagement>(sm: &mut S) -> bool {
+        let bsr = sm.smi_read(PHY_REG_BSR);
+        let ssr = sm.smi_read(PHY_REG_SSR);
+
+        // No link without autonegotiate
+        if bsr & PHY_REG_BSR_ANDONE == 0 {
+            return false;
+        }
+        // No link if link is down
+        if bsr & PHY_REG_BSR_UP == 0 {
+            return false;
+        }
+        // No link if autonegotiate incomplete
+        if ssr & PHY_REG_SSR_ANDONE == 0 {
+            return false;
+        }
+        // No link if other side isn't 100Mbps full duplex
+        if ssr & PHY_REG_SSR_SPEED != PHY_REG_SSR_100BASE_FD {
+            return false;
+        }
+
+        // Got link
+        true
+    }
+}
+
+/// Public functions for the LAN8742A
+impl LAN8742A {
+    // Writes a value to an extended PHY register in MMD address space
+    fn smi_write_ext<S: StationManagement>(sm: &mut S, reg_addr: u16, reg_data: u16) {
+        sm.smi_write(PHY_REG_CTL, 0x0003); // set address
+        sm.smi_write(PHY_REG_ADDAR, reg_addr);
+        sm.smi_write(PHY_REG_CTL, 0x4003); // set data
+        sm.smi_write(PHY_REG_ADDAR, reg_data);
+    }
+}
diff --git a/embassy-stm32/src/eth/mod.rs b/embassy-stm32/src/eth/mod.rs
index 8791e1552..e41ebf4d0 100644
--- a/embassy-stm32/src/eth/mod.rs
+++ b/embassy-stm32/src/eth/mod.rs
@@ -3,5 +3,32 @@
 #[cfg_attr(eth_v1, path = "v1.rs")]
 #[cfg_attr(eth_v2, path = "v2/mod.rs")]
 mod _version;
+pub mod lan8742a;
 
 pub use _version::*;
+
+/// Station Management Interface (SMI) on an ethernet PHY
+///
+/// # Safety
+///
+/// The methods cannot move out of self
+pub unsafe trait StationManagement {
+    /// Read a register over SMI.
+    fn smi_read(&mut self, reg: u8) -> u16;
+    /// Write a register over SMI.
+    fn smi_write(&mut self, reg: u8, val: u16);
+}
+
+/// Traits for an Ethernet PHY
+///
+/// # Safety
+///
+/// The methods cannot move S
+pub unsafe trait PHY {
+    /// Reset PHY and wait for it to come out of reset.
+    fn phy_reset<S: StationManagement>(sm: &mut S);
+    /// PHY initialisation.
+    fn phy_init<S: StationManagement>(sm: &mut S);
+    /// Poll link to see if it is up and FD with 100Mbps
+    fn poll_link<S: StationManagement>(sm: &mut S) -> bool;
+}
diff --git a/embassy-stm32/src/eth/v2/mod.rs b/embassy-stm32/src/eth/v2/mod.rs
index d54c6e859..67d722d15 100644
--- a/embassy-stm32/src/eth/v2/mod.rs
+++ b/embassy-stm32/src/eth/v2/mod.rs
@@ -14,32 +14,21 @@ use crate::interrupt::Interrupt;
 use crate::pac::gpio::vals::Ospeedr;
 use crate::pac::ETH;
 use crate::peripherals;
+use crate::time::Hertz;
 
 mod descriptors;
+use super::{StationManagement, PHY};
 use descriptors::DescriptorRing;
 
-/// Station Management Interface (SMI) on an ethernet PHY
-pub trait StationManagement {
-    /// Read a register over SMI.
-    fn smi_read(&mut self, reg: u8) -> u16;
-    /// Write a register over SMI.
-    fn smi_write(&mut self, reg: u8, val: u16);
-}
-
-/// Traits for an Ethernet PHY
-pub trait PHY {
-    /// Reset PHY and wait for it to come out of reset.
-    fn phy_reset(&mut self);
-    /// PHY initialisation.
-    fn phy_init(&mut self);
-}
-
-pub struct Ethernet<'d, T: Instance, const TX: usize, const RX: usize> {
+pub struct Ethernet<'d, T: Instance, P: PHY, const TX: usize, const RX: usize> {
     state: PeripheralMutex<Inner<'d, T, TX, RX>>,
     pins: [AnyPin; 9],
+    _phy: P,
+    clock_range: u8,
+    phy_addr: u8,
 }
 
-impl<'d, T: Instance, const TX: usize, const RX: usize> Ethernet<'d, T, TX, RX> {
+impl<'d, T: Instance, P: PHY, const TX: usize, const RX: usize> Ethernet<'d, T, P, TX, RX> {
     pub fn new(
         peri: impl Unborrow<Target = T> + 'd,
         interrupt: impl Unborrow<Target = T::Interrupt> + 'd,
@@ -52,7 +41,10 @@ impl<'d, T: Instance, const TX: usize, const RX: usize> Ethernet<'d, T, TX, RX>
         tx_d0: impl Unborrow<Target = impl TXD0Pin<T>> + 'd,
         tx_d1: impl Unborrow<Target = impl TXD1Pin<T>> + 'd,
         tx_en: impl Unborrow<Target = impl TXEnPin<T>> + 'd,
+        phy: P,
         mac_addr: [u8; 6],
+        hclk: Hertz,
+        phy_addr: u8,
     ) -> Self {
         unborrow!(interrupt, ref_clk, mdio, mdc, crs, rx_d0, rx_d1, tx_d0, tx_d1, tx_en);
 
@@ -116,6 +108,20 @@ impl<'d, T: Instance, const TX: usize, const RX: usize> Ethernet<'d, T, TX, RX>
             });
         }
 
+        // Set the MDC clock frequency in the range 1MHz - 2.5MHz
+        let hclk_mhz = hclk.0 / 1_000_000;
+        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")
+            }
+        };
+
         let pins = [
             ref_clk.degrade(),
             mdio.degrade(),
@@ -128,7 +134,13 @@ impl<'d, T: Instance, const TX: usize, const RX: usize> Ethernet<'d, T, TX, RX>
             tx_en.degrade(),
         ];
 
-        Self { state, pins }
+        Self {
+            state,
+            pins,
+            _phy: phy,
+            clock_range,
+            phy_addr,
+        }
     }
 
     pub fn init(self: Pin<&mut Self>) {
@@ -163,10 +175,52 @@ impl<'d, T: Instance, const TX: usize, const RX: usize> Ethernet<'d, T, TX, RX>
                 });
             }
         });
+        P::phy_reset(this);
+        P::phy_init(this);
+    }
+}
+
+unsafe impl<'d, T: Instance, P: PHY, const TX: usize, const RX: usize> StationManagement
+    for Ethernet<'d, T, P, TX, RX>
+{
+    fn smi_read(&mut self, reg: u8) -> u16 {
+        // NOTE(unsafe) These registers aren't used in the interrupt and we have `&mut self`
+        unsafe {
+            let mac = ETH.ethernet_mac();
+
+            mac.macmdioar().modify(|w| {
+                w.set_pa(self.phy_addr);
+                w.set_rda(reg);
+                w.set_goc(0b11); // read
+                w.set_cr(self.clock_range);
+                w.set_mb(true);
+            });
+            while mac.macmdioar().read().mb() {}
+            mac.macmdiodr().read().md()
+        }
+    }
+
+    fn smi_write(&mut self, reg: u8, val: u16) {
+        // NOTE(unsafe) These registers aren't used in the interrupt and we have `&mut self`
+        unsafe {
+            let mac = ETH.ethernet_mac();
+
+            mac.macmdiodr().write(|w| w.set_md(val));
+            mac.macmdioar().modify(|w| {
+                w.set_pa(self.phy_addr);
+                w.set_rda(reg);
+                w.set_goc(0b01); // write
+                w.set_cr(self.clock_range);
+                w.set_mb(true);
+            });
+            while mac.macmdioar().read().mb() {}
+        }
     }
 }
 
-impl<'d, T: Instance, const TX: usize, const RX: usize> Drop for Ethernet<'d, T, TX, RX> {
+impl<'d, T: Instance, P: PHY, const TX: usize, const RX: usize> Drop
+    for Ethernet<'d, T, P, TX, RX>
+{
     fn drop(&mut self) {
         for pin in self.pins.iter_mut() {
             // NOTE(unsafe) Exclusive access to the regs