From 9c94a5cd86aeafd1e05d610fc0e34196a840b5c0 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Sun, 23 Oct 2016 15:26:36 -0600
Subject: [PATCH] Event based ethernetd

---
 e1000d/src/device.rs | 22 +++++++++++++++++++++-
 e1000d/src/main.rs   |  5 +++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/e1000d/src/device.rs b/e1000d/src/device.rs
index 86047283d1..edadeb1aab 100644
--- a/e1000d/src/device.rs
+++ b/e1000d/src/device.rs
@@ -140,7 +140,8 @@ impl Scheme for Intel8254x {
             }
         }
 
-        Err(Error::new(EWOULDBLOCK))
+        //Err(Error::new(EWOULDBLOCK))
+        Ok(0)
     }
 
     fn write(&self, _id: usize, buf: &[u8]) -> Result<usize> {
@@ -225,6 +226,25 @@ impl Intel8254x {
         icr != 0
     }
 
+    pub fn next_read(&self) -> usize {
+        let head = unsafe { self.read(RDH) };
+        let mut tail = unsafe { self.read(RDT) };
+
+        tail += 1;
+        if tail >= self.receive_ring.len() as u32 {
+            tail = 0;
+        }
+
+        if tail != head {
+            let rd = unsafe { &* (self.receive_ring.as_ptr().offset(tail as isize) as *const Rd) };
+            if rd.status & RD_DD == RD_DD {
+                return rd.length as usize;
+            }
+        }
+
+        0
+    }
+
     pub unsafe fn read(&self, register: u32) -> u32 {
         ptr::read_volatile((self.base + register as usize) as *mut u32)
     }
diff --git a/e1000d/src/main.rs b/e1000d/src/main.rs
index a80303bc94..c6a98f277c 100644
--- a/e1000d/src/main.rs
+++ b/e1000d/src/main.rs
@@ -69,6 +69,11 @@ fn main() {
                             todo.remove(i);
                         }
                     }
+
+                    let next_read = device_irq.next_read();
+                    if next_read > 0 {
+                        return Ok(Some(next_read));
+                    }
                 }
                 Ok(None)
             }).expect("e1000d: failed to catch events on IRQ file");