Make EC drivers optional

First step to getting the crate to support no_std so that we can use it
in UEFI. Avoid compiling code to interface with Linux drivers and the
dependencies we need for that.

Signed-off-by: Daniel Schaefer <[email protected]>

Author: JohnAZoidberg

.github/workflows/ci.yml

@@ -12,11 +12,17 @@ jobs:
     - name: Setup Rust toolchain
       run: rustup show
 
-    - name: Run cargo build
+    - name: Build without optional features
       uses: actions-rs/cargo@v1
       with:
         command: build
 
+    - name: Build with all features enabled
+      uses: actions-rs/cargo@v1
+      with:
+        command: build
+        args: --all-features
+
   test:
     name: Test Suite
     runs-on: ubuntu-latest

framework_lib/Cargo.toml

@@ -5,21 +5,31 @@ edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+default = []
+# EC communication via Port I/O on Linux
+linux_pio = ["dep:libc"]
+# EC communication via raw Port I/O (e.g. UEFI or other ring 0 code)
+raw_pio = []
+# EC communication via cros_ec driver on Linux
+cros_ec_driver = ["dep:nix"]
+
 [dependencies]
 regex = "1.6.0" # TODO: Can update to 1.7.0
 # TODO: This doesn't work on:
 # - Windows
 # - Linux when SecureBoot (Lockdown) is enabled
 # Need to use the driver in those cases
 redox_hwio = "0.1.6"
-libc = "0.2.137"
+libc = { version = "0.2.137", optional = true }
 clap = { version = "4.0", features = ["derive"] }
-nix = "0.25.0"
+nix = { version = "0.25.0", optional = true }
 num = "0.4"
 num-derive = "0.3"
 num-traits = "0.2"
-#[target.'cfg(windows)'.dependencies]
+
 [dependencies.windows]
+optional = true
 version = "0.42.0"
 features = [
     "Win32_Foundation",

framework_lib/src/chromium_ec/mod.rs

@@ -1,6 +1,7 @@
 use crate::util;
 
 use num_derive::FromPrimitive;
+#[cfg(feature = "cros_ec_driver")]
 mod cros_ec;
 mod portio;
 //mod windows;
@@ -57,7 +58,9 @@ pub fn read_memory(offset: u16, length: u16) -> Option<Vec<u8>> {
     match 0 {
         0 => portio::read_memory(offset, length),
         //1 => windows::read_memory(offset, length),
-        _ => cros_ec::read_memory(offset, length),
+        #[cfg(feature = "cros_ec_driver")]
+        2 => cros_ec::read_memory(offset, length),
+        _ => None,
     }
 }
 
@@ -76,7 +79,9 @@ pub fn send_command(command: u16, command_version: u8, data: &[u8]) -> Option<Ve
     match 0 {
         0 => portio::send_command(command, command_version, data),
         //1 => windows::send_command(command, command_version, data),
-        _ => cros_ec::send_command(command, command_version, data),
+        #[cfg(feature = "cros_ec_driver")]
+        2 => cros_ec::send_command(command, command_version, data),
+        _ => None,
     }
 }
 

framework_lib/src/chromium_ec/portio.rs

@@ -1,5 +1,7 @@
 use core::convert::TryInto;
 use hwio::{Io, Pio};
+#[cfg(feature = "linux_pio")]
+use libc::ioperm;
 
 use crate::chromium_ec::EC_MEMMAP_SIZE;
 use crate::os_specific;
@@ -277,10 +279,10 @@ fn transfer_read(address: u16, size: u16) -> Vec<u8> {
     buffer
 }
 
-use libc::ioperm;
 fn init() {
     // In Linux userspace has to first request access to ioports
     // TODO: Close these again after we're done
+    #[cfg(feature = "linux_pio")]
     unsafe {
         ioperm(EC_LPC_ADDR_HOST_DATA as u64, 8, 1);
         ioperm(MEC_LPC_ADDRESS_REGISTER0 as u64, 10, 1);