devices: Add pci_types

Start PCI work by defining an enum to represent the four PCI interrupt
lines.

Change-Id: Ib95a4e4a03f0d6917ed2bed4b1afb97d18ff4f9e
Signed-off-by: Dylan Reid <dgreid@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1072573
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>

devices/src/lib.rs

@@ -20,6 +20,7 @@ extern crate vm_control;
 mod bus;
 mod cmos;
 mod i8042;
+mod pci;
 mod proxy;
 mod serial;
 pub mod pl030;
@@ -29,6 +30,7 @@ pub use self::bus::{Bus, BusDevice};
 pub use self::cmos::Cmos;
 pub use self::pl030::Pl030;
 pub use self::i8042::I8042Device;
+pub use self::pci::PciInterruptPin;
 pub use self::proxy::ProxyDevice;
 pub use self::proxy::Error as ProxyError;
 pub use self::serial::Serial;

devices/src/pci/mod.rs

@@ -0,0 +1,20 @@
+// Copyright 2018 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+//! Implements pci devices and busses.
+
+/// PCI has four interrupt pins A->D.
+#[derive(Copy, Clone)]
+pub enum PciInterruptPin {
+    IntA,
+    IntB,
+    IntC,
+    IntD,
+}
+
+impl PciInterruptPin {
+    pub fn to_mask(self) -> u32 {
+        self as u32
+    }
+}