From e1ac328ce63c30031ef0a38139dd02fae98704ff Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Wed, 15 Mar 2023 12:02:34 +1100
Subject: [PATCH] embedded-hal

---
 agb/Cargo.toml             |  2 ++
 agb/src/serial_link/mod.rs | 73 ++++++++++++++++++++++++++++++--------
 2 files changed, 60 insertions(+), 15 deletions(-)

diff --git a/agb/Cargo.toml b/agb/Cargo.toml
index 36659cdf..ba932d84 100644
--- a/agb/Cargo.toml
+++ b/agb/Cargo.toml
@@ -29,6 +29,8 @@ agb_fixnum = { version = "0.13.0", path = "../agb-fixnum" }
 bare-metal = "1"
 modular-bitfield = "0.11"
 rustc-hash =  { version = "1", default-features = false }
+embedded-hal = "0.2.7"
+nb = "1.1"
 
 [package.metadata.docs.rs]
 default-target = "thumbv6m-none-eabi"
diff --git a/agb/src/serial_link/mod.rs b/agb/src/serial_link/mod.rs
index ce1540a3..9775b2cf 100644
--- a/agb/src/serial_link/mod.rs
+++ b/agb/src/serial_link/mod.rs
@@ -1,41 +1,67 @@
-use core::ops::Deref;
+use core::ops::{Deref, DerefMut};
 
-use crate::memory_mapped::MemoryMapped;
+use embedded_hal::serial::{Read, Write};
+
+use crate::{memory_mapped::MemoryMapped, println};
 
 const SIODATA8: MemoryMapped<u16> = unsafe { MemoryMapped::new(0x0400_012A) };
 const SIOCNT: MemoryMapped<u16> = unsafe { MemoryMapped::new(0x0400_0128) };
 const RCNT: MemoryMapped<u16> = unsafe { MemoryMapped::new(0x0400_0134) };
 
+#[derive(Debug)]
 pub enum LinkPortError {
     GbaErrorBit,
-    Blocked,
 }
 
 pub struct LinkPortUart;
 
 impl LinkPortUart {
-    pub fn init(rate: BaudRate) -> Self {
+    pub fn init(rate: BaudRate, with_interrupts: bool, clear_to_send: bool) -> Self {
+        println!("begin init");
         RCNT.set(0x0);
-        SIOCNT.set(SioControlReg::default_uart().with_baud(rate).into());
+        println!("have set rcnt");
+        SIOCNT.set(0x0);
+        let reg: u16 = SioControlReg::default_uart()
+            .with_baud(rate)
+            .with_interrupts(with_interrupts)
+            .with_cts(clear_to_send)
+            .into();
+        SIOCNT.set(reg);
+        println!("have set siocnt to {reg:#X}/{reg:#b}");
         Self
     }
+}
 
-    pub fn read(&mut self) -> Result<u8, LinkPortError> {
+impl Read<u8> for LinkPortUart {
+    type Error = LinkPortError;
+
+    fn read(&mut self) -> Result<u8, nb::Error<LinkPortError>> {
         match SioControlReg::from(SIOCNT.get()) {
-            v if *v.error => Err(LinkPortError::GbaErrorBit),
-            v if *v.recv_empty => Err(LinkPortError::Blocked),
+            v if *v.error => Err(nb::Error::Other(LinkPortError::GbaErrorBit)),
+            v if *v.recv_empty => Err(nb::Error::WouldBlock),
             _ => Ok((SIODATA8.get() & 0xFF) as u8),
         }
     }
+}
 
-    pub fn write(&mut self, data: u8) -> Result<(), LinkPortError> {
-        match SioControlReg::from(SIOCNT.get()) {
-            v if *v.error => Err(LinkPortError::GbaErrorBit),
-            v if *v.send_full => Err(LinkPortError::Blocked),
-            _ => {
-                SIODATA8.set(data as u16);
+impl Write<u8> for LinkPortUart {
+    type Error = LinkPortError;
+
+    fn write(&mut self, word: u8) -> nb::Result<(), Self::Error> {
+        match self.flush() {
+            Ok(_) => {
+                SIODATA8.set(word as u16);
                 Ok(())
             }
+            Err(e) => Err(e),
+        }
+    }
+
+    fn flush(&mut self) -> nb::Result<(), Self::Error> {
+        match SioControlReg::from(SIOCNT.get()) {
+            v if *v.error => Err(nb::Error::Other(LinkPortError::GbaErrorBit)),
+            v if *v.send_full => Err(nb::Error::WouldBlock),
+            _ => Ok(()),
         }
     }
 }
@@ -104,6 +130,7 @@ impl SioControlReg {
             recv_empty: BoolField(false),
             error: BoolField(false),
             data_8bit: BoolField(true),
+            // fifo_enabled: BoolField(true),
             fifo_enabled: BoolField(true),
             parity_enabled: BoolField(false),
             tx_enabled: BoolField(true),
@@ -117,6 +144,16 @@ impl SioControlReg {
         self.baud_rate = rate;
         self
     }
+
+    fn with_interrupts(mut self, interrupts: bool) -> Self {
+        *self.irq_enable = interrupts;
+        self
+    }
+
+    fn with_cts(mut self, clear_to_send: bool) -> Self {
+        *self.flow_control = clear_to_send;
+        self
+    }
 }
 
 impl From<SioControlReg> for u16 {
@@ -127,7 +164,7 @@ impl From<SioControlReg> for u16 {
             | u16::from(value.send_full) << 4
             | u16::from(value.recv_empty) << 5
             | u16::from(value.error) << 6
-            | u16::from(value.data_8bit) << 7
+            | u16::from(value.data_8bit) << 7 // bit start
             | u16::from(value.fifo_enabled) << 8
             | u16::from(value.parity_enabled) << 9
             | u16::from(value.tx_enabled) << 10
@@ -167,6 +204,12 @@ impl Deref for BoolField {
     }
 }
 
+impl DerefMut for BoolField {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
 impl From<BoolField> for u16 {
     fn from(value: BoolField) -> Self {
         if *value {