add gpio abstraction

firmware/Cargo.lock

@@ -94,6 +94,15 @@ dependencies = [
  "build_const 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "embedded-hal"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "nb 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "generic-array"
 version = "0.12.3"
@@ -109,6 +118,7 @@ dependencies = [
  "cortex-m 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "cortex-m-rt 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "crc 1.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "embedded-hal 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "libm 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "smoltcp 0.4.0 (git+https://github.com/m-labs/smoltcp?rev=cd893e6)",
  "tm4c129x 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -134,6 +144,11 @@ name = "managed"
 version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "nb"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "proc-macro2"
 version = "0.4.30"
@@ -257,6 +272,11 @@ name = "vcell"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "void"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "volatile-register"
 version = "0.2.0"
@@ -298,10 +318,12 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum cortex-m-rt 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)" = "17805910e3ecf029bdbfcc42b7384d9e3d9e5626153fa810002c1ef9839338ac"
 "checksum cortex-m-rt-macros 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "d7ae692573e0acccb1579fef1abf5a5bf1d2f3f0149a22b16870ec9309aee25f"
 "checksum crc 1.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d663548de7f5cca343f1e0a48d14dcfb0e9eb4e079ec58883b7251539fa10aeb"
+"checksum embedded-hal 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ee4908a155094da7723c2d60d617b820061e3b4efcc3d9e293d206a5a76c170b"
 "checksum generic-array 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)" = "c68f0274ae0e023facc3c97b2e00f076be70e254bc851d972503b328db79b2ec"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
 "checksum libm 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "7fc7aa29613bd6a620df431842069224d8bc9011086b1db4c0e0cd47fa03ec9a"
 "checksum managed 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "43e2737ecabe4ae36a68061398bf27d2bfd0763f4c3c837a398478459494c4b7"
+"checksum nb 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b1411551beb3c11dedfb0a90a0fa256b47d28b9ec2cdff34c25a2fa59e45dbdc"
 "checksum proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)" = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
 "checksum quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)" = "6ce23b6b870e8f94f81fb0a363d65d86675884b34a09043c81e5562f11c1f8e1"
 "checksum r0 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e2a38df5b15c8d5c7e8654189744d8e396bddc18ad48041a500ce52d6948941f"
@@ -319,6 +341,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "612d636f949607bdf9b123b4a6f6d966dedf3ff669f7f045890d3a4a73948169"
 "checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
 "checksum vcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "45c297f0afb6928cd08ab1ff9d95e99392595ea25ae1b5ecf822ff8764e57a0d"
+"checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 "checksum volatile-register 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0d67cb4616d99b940db1d6bd28844ff97108b498a6ca850e5b6191a532063286"
 "checksum walkdir 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "bb08f9e670fab86099470b97cd2b252d6527f0b3cc1401acdb595ffc9dd288ff"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"

firmware/Cargo.toml

@@ -12,6 +12,7 @@ cortex-m = { version = "0.5", features = ["const-fn"] }
 cortex-m-rt = "0.6"
 crc = { version = "1.7", default-features = false }
 tm4c129x = { version = "0.8", features = ["rt"] }
+embedded-hal = { version = "0.2", features = ["unproven"] }
 
 [dependencies.smoltcp]
 git = "https://github.com/m-labs/smoltcp"

firmware/src/board/gpio.rs

@@ -0,0 +1,73 @@
+use core::mem::transmute;
+use core::slice::from_raw_parts_mut;
+use embedded_hal::digital::v2::{InputPin, OutputPin};
+
+pub trait Gpio where Self: Sized {
+    fn into_output(self) -> GpioOutput<Self>;
+    fn into_input(self) -> GpioInput<Self>;
+}
+
+pub struct GpioInput<PIN>(PIN);
+pub struct GpioOutput<PIN>(PIN);
+
+macro_rules! def_gpio {
+    ($PORT: tt, $PIN: tt, $idx: expr) => (
+        impl Gpio for $PIN {
+            fn into_output(self) -> GpioOutput<Self> {
+                let gpio = unsafe { &*tm4c129x::$PORT::ptr() };
+                gpio.dir.modify(|_, w| w.dir().bits(1 << $idx));
+                gpio.den.modify(|_, w| w.den().bits(1 << $idx));
+                GpioOutput(self)
+            }
+            fn into_input(self) -> GpioInput<Self> {
+                let gpio = unsafe { &*tm4c129x::$PORT::ptr() };
+                gpio.dir.modify(|_, w| w.dir().bits(1 << $idx));
+                gpio.den.modify(|_, w| w.den().bits(1 << $idx));
+                GpioInput(self)
+            }
+        }
+
+        impl InputPin for GpioInput<$PIN> {
+            type Error = ();
+            fn is_high(&self) -> Result<bool, Self::Error> {
+                let gpio = unsafe { &*tm4c129x::$PORT::ptr() };
+                Ok(gpio.data.read().data().bits() & (1 << $idx) == (1 << $idx))
+            }
+            fn is_low(&self) -> Result<bool, Self::Error> {
+                let gpio = unsafe { &*tm4c129x::$PORT::ptr() };
+                Ok(gpio.data.read().data().bits() & (1 << $idx) != (1 << $idx))
+            }
+        }
+
+        impl OutputPin for GpioOutput<$PIN> {
+            type Error = ();
+            fn set_low(&mut self) -> Result<(), Self::Error> {
+                let gpio = unsafe { &*tm4c129x::$PORT::ptr() };
+                let data = masked_data(unsafe { transmute(&gpio.data) }, $idx);
+                *data = 0;
+                Ok(())
+            }
+            fn set_high(&mut self) -> Result<(), Self::Error> {
+                let gpio = unsafe { &*tm4c129x::$PORT::ptr() };
+                let data = masked_data(unsafe { transmute(&gpio.data) }, $idx);
+                *data = 1 << $idx;
+                Ok(())
+            }
+        }
+    )
+}
+
+pub struct PB4;
+def_gpio!(GPIO_PORTB_AHB, PB4, 4);
+pub struct PB5;
+def_gpio!(GPIO_PORTB_AHB, PB5, 5);
+pub struct PE4;
+def_gpio!(GPIO_PORTE_AHB, PE4, 5);
+pub struct PE5;
+def_gpio!(GPIO_PORTE_AHB, PE5, 5);
+
+/// Setting of GPIO pins is optimized by address masking
+fn masked_data<'a>(data: *mut u32, bits: u8) -> &'a mut u32 {
+    let data = unsafe { from_raw_parts_mut(data, 0x100) };
+    &mut data[usize::from(bits)]
+}

firmware/src/board/mod.rs

@@ -1,6 +1,8 @@
 use cortex_m;
 use tm4c129x;
 
+mod gpio;
+
 
 const LED1: u8 = 0x10; // PK4
 const LED2: u8 = 0x40; // PK6

firmware/src/main.rs

@@ -10,6 +10,7 @@ extern crate cortex_m_rt;
 extern crate tm4c129x;
 extern crate smoltcp;
 extern crate crc;
+extern crate embedded_hal;
 
 use core::cell::{Cell, RefCell};
 use core::fmt;