Add speaker device for the beep command

src/api/fs.rs

@@ -170,6 +170,7 @@ fn device_type(name: &str) -> Result<DeviceType, ()> {
         "vga-font"    => Ok(DeviceType::VgaFont),
         "vga-mode"    => Ok(DeviceType::VgaMode),
         "vga-palette" => Ok(DeviceType::VgaPalette),
+        "speaker"     => Ok(DeviceType::Speaker),
         "ata"         => Ok(DeviceType::Drive),
         _             => Err(()),
     }

src/sys/fs/device.rs

@@ -9,6 +9,7 @@ use crate::sys::console::Console;
 use crate::sys::net::socket::tcp::TcpSocket;
 use crate::sys::net::socket::udp::UdpSocket;
 use crate::sys::rng::Random;
+use crate::sys::speaker::Speaker;
 use crate::sys::vga::{VgaFont, VgaMode, VgaPalette, VgaBuffer};
 
 use alloc::vec;
@@ -33,6 +34,7 @@ pub enum DeviceType {
     VgaFont    = 11,
     VgaMode    = 12,
     VgaPalette = 13,
+    Speaker    = 14,
 }
 
 impl TryFrom<&[u8]> for DeviceType {
@@ -54,6 +56,7 @@ impl TryFrom<&[u8]> for DeviceType {
             11 => Ok(DeviceType::VgaFont),
             12 => Ok(DeviceType::VgaMode),
             13 => Ok(DeviceType::VgaPalette),
+            14 => Ok(DeviceType::Speaker),
              _ => Err(()),
         }
     }
@@ -98,6 +101,7 @@ pub enum Device {
     VgaFont(VgaFont),
     VgaMode(VgaMode),
     VgaPalette(VgaPalette),
+    Speaker(Speaker),
     Drive(Drive),
 }
 
@@ -119,6 +123,7 @@ impl TryFrom<&[u8]> for Device {
             DeviceType::VgaFont    => Ok(Device::VgaFont(VgaFont::new())),
             DeviceType::VgaMode    => Ok(Device::VgaMode(VgaMode::new())),
             DeviceType::VgaPalette => Ok(Device::VgaPalette(VgaPalette::new())),
+            DeviceType::Speaker    => Ok(Device::Speaker(Speaker::new())),
             DeviceType::Drive if buf.len() > 2 => {
                 let bus = buf[1];
                 let dsk = buf[2];
@@ -181,6 +186,7 @@ impl FileIO for Device {
             Device::VgaFont(io)    => io.read(buf),
             Device::VgaMode(io)    => io.read(buf),
             Device::VgaPalette(io) => io.read(buf),
+            Device::Speaker(io)    => io.read(buf),
             Device::Drive(io)      => io.read(buf),
         }
     }
@@ -200,6 +206,7 @@ impl FileIO for Device {
             Device::VgaFont(io)    => io.write(buf),
             Device::VgaMode(io)    => io.write(buf),
             Device::VgaPalette(io) => io.write(buf),
+            Device::Speaker(io)    => io.write(buf),
             Device::Drive(io)      => io.write(buf),
         }
     }
@@ -219,6 +226,7 @@ impl FileIO for Device {
             Device::VgaFont(io)    => io.close(),
             Device::VgaMode(io)    => io.close(),
             Device::VgaPalette(io) => io.close(),
+            Device::Speaker(io)    => io.close(),
             Device::Drive(io)      => io.close(),
         }
     }
@@ -238,6 +246,7 @@ impl FileIO for Device {
             Device::VgaFont(io)    => io.poll(event),
             Device::VgaMode(io)    => io.poll(event),
             Device::VgaPalette(io) => io.poll(event),
+            Device::Speaker(io)    => io.poll(event),
             Device::Drive(io)      => io.poll(event),
         }
     }

src/sys/mod.rs

@@ -54,5 +54,6 @@ pub mod pic;
 pub mod process;
 pub mod rng;
 pub mod serial;
+pub mod speaker;
 pub mod syscall;
 pub mod vga;

src/sys/speaker.rs

@@ -0,0 +1,65 @@
+use super::clk;
+
+use crate::api::fs::{FileIO, IO};
+
+use core::convert::TryInto;
+use x86_64::instructions::port::Port;
+
+#[derive(Debug, Clone)]
+pub struct Speaker;
+
+impl Speaker {
+    pub fn new() -> Self {
+        Self {}
+    }
+}
+
+impl FileIO for Speaker {
+    fn read(&mut self, _buf: &mut [u8]) -> Result<usize, ()> {
+        Err(())
+    }
+
+    fn write(&mut self, buf: &[u8]) -> Result<usize, ()> {
+        if let Ok(bytes) = buf.try_into() {
+            match f64::from_be_bytes(bytes) {
+                0.0 => stop_sound(),
+                freq => start_sound(freq),
+            }
+            return Ok(8);
+        }
+        Err(())
+    }
+
+    fn close(&mut self) {}
+
+    fn poll(&mut self, event: IO) -> bool {
+        match event {
+            IO::Read => false,
+            IO::Write => true,
+        }
+    }
+}
+
+// See: https://wiki.osdev.org/PC_Speaker
+
+const SPEAKER_PORT: u16 = 0x61;
+
+fn start_sound(freq: f64) {
+    debug!("speaker::start_sound({})", freq);
+    let divider = (clk::pit_frequency() / freq) as u16;
+    let channel = 2;
+    clk::set_pit_frequency(divider, channel);
+
+    let mut speaker: Port<u8> = Port::new(SPEAKER_PORT);
+    let tmp = unsafe { speaker.read() };
+    if tmp != (tmp | 3) {
+        unsafe { speaker.write(tmp | 3) };
+    }
+}
+
+fn stop_sound() {
+    debug!("speaker::stop_sound()");
+    let mut speaker: Port<u8> = Port::new(SPEAKER_PORT);
+    let tmp = unsafe { speaker.read() } & 0xFC;
+    unsafe { speaker.write(tmp) };
+}

src/usr/beep.rs

@@ -1,35 +1,28 @@
 use crate::api::console::Style;
 use crate::api::process::ExitCode;
-use crate::{api, sys};
+use crate::api::fs;
+use crate::api::syscall;
 
-use x86_64::instructions::port::Port;
+const SPEAKER: &'static str = "/dev/speaker";
 
-// See: https://wiki.osdev.org/PC_Speaker
-
-const SPEAKER_PORT: u16 = 0x61;
-
-fn start_sound(freq: f64) {
-    let divider = (sys::clk::pit_frequency() / freq) as u16;
-    let channel = 2;
-    sys::clk::set_pit_frequency(divider, channel);
-
-    let mut speaker: Port<u8> = Port::new(SPEAKER_PORT);
-    let tmp = unsafe { speaker.read() };
-    if tmp != (tmp | 3) {
-        unsafe { speaker.write(tmp | 3) };
+fn start_sound(freq: f64) -> Result<(), ExitCode> {
+    let buf = freq.to_be_bytes();
+    if !fs::is_device(SPEAKER) || fs::write(SPEAKER, &buf).is_err() {
+        error!("Could not write to '{}'", SPEAKER);
+        Err(ExitCode::Failure)
+    } else {
+        Ok(())
     }
 }
 
-fn stop_sound() {
-    let mut speaker: Port<u8> = Port::new(SPEAKER_PORT);
-    let tmp = unsafe { speaker.read() } & 0xFC;
-    unsafe { speaker.write(tmp) };
+fn stop_sound() -> Result<(), ExitCode> {
+    start_sound(0.0)
 }
 
-fn beep(freq: f64, len: f64) {
-    start_sound(freq);
-    api::syscall::sleep(len);
-    stop_sound();
+fn beep(freq: f64, len: f64) -> Result<(), ExitCode> {
+    start_sound(freq)?;
+    syscall::sleep(len);
+    stop_sound()
 }
 
 pub fn main(args: &[&str]) -> Result<(), ExitCode> {
@@ -75,8 +68,7 @@ pub fn main(args: &[&str]) -> Result<(), ExitCode> {
         i += 1;
     }
 
-    beep(freq, len / 1000.0);
-    Ok(())
+    beep(freq, len / 1000.0)
 }
 
 fn help() -> Result<(), ExitCode> {

src/usr/install.rs

@@ -57,11 +57,12 @@ pub fn copy_files(verbose: bool) {
     create_dev("/dev/clk/boot", "clk-boot", verbose);
     create_dev("/dev/clk/epoch", "clk-epoch", verbose);
     create_dev("/dev/clk/rtc", "clk-rtc", verbose);
-    create_dev("/dev/null", "null", verbose);
-    create_dev("/dev/random", "random", verbose);
     create_dev("/dev/console", "console", verbose);
     create_dev("/dev/net/tcp", "tcp", verbose);
     create_dev("/dev/net/udp", "udp", verbose);
+    create_dev("/dev/null", "null", verbose);
+    create_dev("/dev/random", "random", verbose);
+    create_dev("/dev/speaker", "speaker", verbose);
     create_dev("/dev/vga/buffer", "vga-buffer", verbose);
     create_dev("/dev/vga/font", "vga-font", verbose);
     create_dev("/dev/vga/mode", "vga-mode", verbose);