added virtio-console support.

src/console.rs

@@ -0,0 +1,130 @@
+use super::*;
+use crate::queue::VirtQueue;
+use bitflags::*;
+use core::sync::atomic::spin_loop_hint;
+use log::*;
+use volatile::{ReadOnly, WriteOnly};
+
+const QUEUE_RECEIVEQ_PORT_0: usize = 0;
+const QUEUE_TRANSMITQ_PORT_0: usize = 1;
+
+/// Virtio console. Only one single port is allowed since ``alloc'' is disabled.
+/// Emergency and cols/rows unimplemented.
+pub struct VirtIOConsole<'a> {
+    header: &'static mut VirtIOHeader,
+    receiveq: VirtQueue<'a>,
+    transmitq: VirtQueue<'a>,
+    queue_buf_dma: DMA,
+    queue_buf_rx: &'a mut [u8],
+    cursor: usize,
+    pending_len: usize,
+}
+
+impl<'a> VirtIOConsole<'a> {
+    /// Create a new VirtIO-Console driver.
+    pub fn new(header: &'static mut VirtIOHeader) -> Result<Self> {
+        header.begin_init(|features| {
+            let features = Features::from_bits_truncate(features);
+            info!("Device features {:?}", features);
+            let supported_features = Features::empty();
+            (features & supported_features).bits()
+        });
+        let config = unsafe { &mut *(header.config_space() as *mut Config) };
+        info!("Config: {:?}", config);
+        let receiveq = VirtQueue::new(header, QUEUE_RECEIVEQ_PORT_0, 2)?;
+        let transmitq = VirtQueue::new(header, QUEUE_TRANSMITQ_PORT_0, 2)?;
+        let queue_buf_dma = DMA::new(1)?;
+        let queue_buf_rx = unsafe { &mut queue_buf_dma.as_buf()[0..] };
+        header.finish_init();
+        let mut console = VirtIOConsole {
+            header,
+            receiveq,
+            transmitq,
+            queue_buf_dma,
+            queue_buf_rx,
+            cursor: 0,
+            pending_len: 0,
+        };
+        console.poll_retrieve()?;
+        Ok(console)
+    }
+    fn poll_retrieve(&mut self) -> Result<()> {
+        self.receiveq.add(&[], &[self.queue_buf_rx])?;
+        Ok(())
+    }
+    /// Acknowledge interrupt.
+    pub fn ack_interrupt(&mut self) -> Result<bool> {
+        let ack = self.header.ack_interrupt();
+        if !ack {
+            return Ok(false);
+        }
+        let mut flag = false;
+        while let Ok((_token, len)) = self.receiveq.pop_used() {
+            assert_eq!(flag, false);
+            flag = true;
+            assert_ne!(len, 0);
+            self.cursor = 0;
+            self.pending_len = len as usize;
+        }
+        Ok(flag)
+    }
+
+    /// Try get char.
+    pub fn recv(&mut self, pop: bool) -> Result<Option<u8>> {
+        if self.cursor == self.pending_len {
+            return Ok(None);
+        }
+        let ch = self.queue_buf_rx[self.cursor];
+        if pop {
+            self.cursor += 1;
+            if self.cursor == self.pending_len {
+                self.poll_retrieve()?;
+            }
+        }
+        Ok(Some(ch))
+    }
+    /// Put a char onto the device.
+    pub fn send(&mut self, chr: u8) -> Result<()> {
+        let buf: [u8; 1] = [chr];
+        self.transmitq.add(&[&buf], &[])?;
+        self.header.notify(QUEUE_TRANSMITQ_PORT_0 as u32);
+        while !self.transmitq.can_pop() {
+            spin_loop_hint();
+        }
+        self.transmitq.pop_used()?;
+        Ok(())
+    }
+}
+
+#[repr(C)]
+#[derive(Debug)]
+struct Config {
+    cols: ReadOnly<u16>,
+    rows: ReadOnly<u16>,
+    max_nr_ports: ReadOnly<u32>,
+    emerg_wr: WriteOnly<u32>,
+}
+
+bitflags! {
+    struct Features: u64 {
+        const SIZE                  = 1 << 0;
+        const MULTIPORT             = 1 << 1;
+        const EMERG_WRITE           = 1 << 2;
+
+        // device independent
+        const NOTIFY_ON_EMPTY       = 1 << 24; // legacy
+        const ANY_LAYOUT            = 1 << 27; // legacy
+        const RING_INDIRECT_DESC    = 1 << 28;
+        const RING_EVENT_IDX        = 1 << 29;
+        const UNUSED                = 1 << 30; // legacy
+        const VERSION_1             = 1 << 32; // detect legacy
+
+        // since virtio v1.1
+        const ACCESS_PLATFORM       = 1 << 33;
+        const RING_PACKED           = 1 << 34;
+        const IN_ORDER              = 1 << 35;
+        const ORDER_PLATFORM        = 1 << 36;
+        const SR_IOV                = 1 << 37;
+        const NOTIFICATION_DATA     = 1 << 38;
+    }
+}

src/lib.rs

@@ -9,6 +9,7 @@
 extern crate log;
 
 mod blk;
+mod console;
 mod gpu;
 mod hal;
 mod header;
@@ -17,6 +18,7 @@ mod net;
 mod queue;
 
 pub use self::blk::VirtIOBlk;
+pub use self::console::VirtIOConsole;
 pub use self::gpu::VirtIOGpu;
 pub use self::header::*;
 pub use self::input::VirtIOInput;