Merge tock#1046

1046: Refactor debug.rs to not be implemented as a kernel process r=alevy a=bradjc

### Pull Request Overview

This pull request changes the debug module to use a normal `uart::UART` interface rather than acting as a process. This simplifies some kernel data structures as they no longer have to handle the case where an app can be a normal app or a kernel app. It also allows boards to easily use a different uart interface (like segger RTT) without having to implement the `Driver` interface as well.

~~This is blocked on tock#1045 but you can help test anyway!~~


### Testing Strategy

This pull request was tested by running hail app and doing debug!()s from a capsule.


### TODO or Help Wanted

n/a


### Documentation Updated

- [x] Updated the relevant files in `/docs`, or no updates are required.

### Formatting

- [x] Ran `make formatall`.


Co-authored-by: Brad Campbell <bradjc5@gmail.com>

Author: bors[bot]

boards/ek-tm4c1294xl/src/main.rs

@@ -12,6 +12,7 @@ extern crate cortexm4;
 extern crate tm4c129x;
 
 use capsules::virtual_alarm::{MuxAlarm, VirtualMuxAlarm};
+use capsules::virtual_uart::{UartDevice, UartMux};
 use kernel::hil;
 use kernel::hil::Controller;
 use kernel::Platform;
@@ -43,7 +44,7 @@ pub static mut STACK_MEMORY: [u8; 0x1000] = [0; 0x1000];
 /// A structure representing this platform that holds references to all
 /// capsules for this platform.
 struct EkTm4c1294xl {
-    console: &'static capsules::console::Console<'static, tm4c129x::uart::UART>,
+    console: &'static capsules::console::Console<'static, UartDevice<'static>>,
     alarm: &'static capsules::alarm::AlarmDriver<
         'static,
         VirtualMuxAlarm<'static, tm4c129x::gpt::AlarmTimer>,
@@ -80,19 +81,49 @@ pub unsafe fn reset_handler() {
     tm4c129x::sysctl::PSYSCTLM
         .setup_system_clock(tm4c129x::sysctl::SystemClockSource::PllPioscAt120MHz);
 
+    // Create a shared UART channel for the console and for kernel debug.
+    let uart_mux = static_init!(
+        UartMux<'static>,
+        UartMux::new(&tm4c129x::uart::UART0, &mut capsules::virtual_uart::RX_BUF)
+    );
+    hil::uart::UART::set_client(&tm4c129x::uart::UART0, uart_mux);
+
+    // Create a UartDevice for the console.
+    let console_uart = static_init!(UartDevice, UartDevice::new(uart_mux, true));
+    console_uart.setup();
+
     let console = static_init!(
-        capsules::console::Console<tm4c129x::uart::UART>,
+        capsules::console::Console<UartDevice>,
         capsules::console::Console::new(
-            &tm4c129x::uart::UART0,
+            console_uart,
             115200,
             &mut capsules::console::WRITE_BUF,
             &mut capsules::console::READ_BUF,
             kernel::Grant::create()
         )
     );
-    hil::uart::UART::set_client(&tm4c129x::uart::UART0, console);
+    hil::uart::UART::set_client(console_uart, console);
     tm4c129x::uart::UART0.specify_pins(&tm4c129x::gpio::PA[0], &tm4c129x::gpio::PA[1]);
 
+    // Create virtual device for kernel debug.
+    let debugger_uart = static_init!(UartDevice, UartDevice::new(uart_mux, false));
+    debugger_uart.setup();
+    let debugger = static_init!(
+        kernel::debug::DebugWriter,
+        kernel::debug::DebugWriter::new(
+            debugger_uart,
+            &mut kernel::debug::OUTPUT_BUF,
+            &mut kernel::debug::INTERNAL_BUF,
+        )
+    );
+    hil::uart::UART::set_client(debugger_uart, debugger);
+
+    let debug_wrapper = static_init!(
+        kernel::debug::DebugWriterWrapper,
+        kernel::debug::DebugWriterWrapper::new(debugger)
+    );
+    kernel::debug::set_debug_writer_wrapper(debug_wrapper);
+
     // Alarm
     let alarm_timer = &tm4c129x::gpt::TIMER0;
     let mux_alarm = static_init!(
@@ -193,10 +224,6 @@ pub unsafe fn reset_handler() {
 
     tm4c1294.console.initialize();
 
-    // Attach the kernel debug interface to this console
-    let kc = static_init!(capsules::console::App, capsules::console::App::default());
-    kernel::debug::assign_console_driver(Some(tm4c1294.console), kc);
-
     debug!("Initialization complete. Entering main loop...\r");
 
     let board_kernel = static_init!(kernel::Kernel, kernel::Kernel::new());

boards/hail/src/main.rs

@@ -18,6 +18,7 @@ extern crate sam4l;
 use capsules::virtual_alarm::{MuxAlarm, VirtualMuxAlarm};
 use capsules::virtual_i2c::{I2CDevice, MuxI2C};
 use capsules::virtual_spi::{MuxSpiMaster, VirtualSpiMasterDevice};
+use capsules::virtual_uart::{UartDevice, UartMux};
 use kernel::hil;
 use kernel::hil::spi::SpiMaster;
 use kernel::hil::Controller;
@@ -60,7 +61,7 @@ pub static mut STACK_MEMORY: [u8; 0x1000] = [0; 0x1000];
 /// A structure representing this platform that holds references to all
 /// capsules for this platform.
 struct Hail {
-    console: &'static capsules::console::Console<'static, sam4l::usart::USART>,
+    console: &'static capsules::console::Console<'static, UartDevice<'static>>,
     gpio: &'static capsules::gpio::GPIO<'static, sam4l::gpio::GPIOPin>,
     alarm: &'static capsules::alarm::AlarmDriver<
         'static,
@@ -202,17 +203,28 @@ pub unsafe fn reset_handler() {
 
     // Initialize USART0 for Uart
     sam4l::usart::USART0.set_mode(sam4l::usart::UsartMode::Uart);
+
+    // Create a shared UART channel for the console and for kernel debug.
+    let uart_mux = static_init!(
+        UartMux<'static>,
+        UartMux::new(&sam4l::usart::USART0, &mut capsules::virtual_uart::RX_BUF)
+    );
+    hil::uart::UART::set_client(&sam4l::usart::USART0, uart_mux);
+
+    // Create a UartDevice for the console.
+    let console_uart = static_init!(UartDevice, UartDevice::new(uart_mux, true));
+    console_uart.setup();
     let console = static_init!(
-        capsules::console::Console<sam4l::usart::USART>,
+        capsules::console::Console<UartDevice>,
         capsules::console::Console::new(
-            &sam4l::usart::USART0,
+            console_uart,
             115200,
             &mut capsules::console::WRITE_BUF,
             &mut capsules::console::READ_BUF,
             kernel::Grant::create()
         )
     );
-    hil::uart::UART::set_client(&sam4l::usart::USART0, console);
+    hil::uart::UART::set_client(console_uart, console);
 
     // Initialize USART3 for Uart
     sam4l::usart::USART3.set_mode(sam4l::usart::UsartMode::Uart);
@@ -472,9 +484,25 @@ pub unsafe fn reset_handler() {
     };
 
     hail.console.initialize();
-    // Attach the kernel debug interface to this console
-    let kc = static_init!(capsules::console::App, capsules::console::App::default());
-    kernel::debug::assign_console_driver(Some(hail.console), kc);
+
+    // Create virtual device for kernel debug.
+    let debugger_uart = static_init!(UartDevice, UartDevice::new(uart_mux, false));
+    debugger_uart.setup();
+    let debugger = static_init!(
+        kernel::debug::DebugWriter,
+        kernel::debug::DebugWriter::new(
+            debugger_uart,
+            &mut kernel::debug::OUTPUT_BUF,
+            &mut kernel::debug::INTERNAL_BUF,
+        )
+    );
+    hil::uart::UART::set_client(debugger_uart, debugger);
+
+    let debug_wrapper = static_init!(
+        kernel::debug::DebugWriterWrapper,
+        kernel::debug::DebugWriterWrapper::new(debugger)
+    );
+    kernel::debug::set_debug_writer_wrapper(debug_wrapper);
 
     // Reset the nRF and setup the UART bus.
     hail.nrf51822.reset();
@@ -483,7 +511,7 @@ pub unsafe fn reset_handler() {
     // Uncomment to measure overheads for TakeCell and MapCell:
     // test_take_map_cell::test_take_map_cell();
 
-    // debug!("Initialization complete. Entering main loop");
+    debug!("Initialization complete. Entering main loop");
 
     let board_kernel = static_init!(kernel::Kernel, kernel::Kernel::new());
 

boards/imix/src/components/console.rs

@@ -18,47 +18,64 @@
 #![allow(dead_code)] // Components are intended to be conditionally included
 
 use capsules::console;
+use capsules::virtual_uart::{UartDevice, UartMux};
 use hil;
 use kernel;
 use kernel::component::Component;
 use kernel::Grant;
-use sam4l;
 
 pub struct ConsoleComponent {
-    uart: &'static sam4l::usart::USART,
+    uart_mux: &'static UartMux<'static>,
     baud_rate: u32,
 }
 
 impl ConsoleComponent {
-    pub fn new(uart: &'static sam4l::usart::USART, rate: u32) -> ConsoleComponent {
+    pub fn new(uart_mux: &'static UartMux, rate: u32) -> ConsoleComponent {
         ConsoleComponent {
-            uart: uart,
+            uart_mux: uart_mux,
             baud_rate: rate,
         }
     }
 }
 
 impl Component for ConsoleComponent {
-    type Output = &'static console::Console<'static, sam4l::usart::USART>;
+    type Output = &'static console::Console<'static, UartDevice<'static>>;
 
     unsafe fn finalize(&mut self) -> Self::Output {
-        sam4l::usart::USART3.set_mode(sam4l::usart::UsartMode::Uart);
+        // Create virtual device for console.
+        let console_uart = static_init!(UartDevice, UartDevice::new(self.uart_mux, true));
+        console_uart.setup();
         let console = static_init!(
-            console::Console<sam4l::usart::USART>,
+            console::Console<UartDevice>,
             console::Console::new(
-                self.uart,
+                console_uart,
                 self.baud_rate,
                 &mut console::WRITE_BUF,
                 &mut console::READ_BUF,
                 Grant::create()
             )
         );
-        hil::uart::UART::set_client(self.uart, console);
+        hil::uart::UART::set_client(console_uart, console);
         console.initialize();
 
-        // Attach the kernel debug interface to this console
-        let kc = static_init!(console::App, console::App::default());
-        kernel::debug::assign_console_driver(Some(console), kc);
+        // Create virtual device for kernel debug.
+        let debugger_uart = static_init!(UartDevice, UartDevice::new(self.uart_mux, false));
+        debugger_uart.setup();
+        let debugger = static_init!(
+            kernel::debug::DebugWriter,
+            kernel::debug::DebugWriter::new(
+                debugger_uart,
+                &mut kernel::debug::OUTPUT_BUF,
+                &mut kernel::debug::INTERNAL_BUF,
+            )
+        );
+        hil::uart::UART::set_client(debugger_uart, debugger);
+
+        let debug_wrapper = static_init!(
+            kernel::debug::DebugWriterWrapper,
+            kernel::debug::DebugWriterWrapper::new(debugger)
+        );
+        kernel::debug::set_debug_writer_wrapper(debug_wrapper);
 
         console
     }

boards/imix/src/main.rs

@@ -23,6 +23,7 @@ use capsules::alarm::AlarmDriver;
 use capsules::virtual_alarm::{MuxAlarm, VirtualMuxAlarm};
 use capsules::virtual_i2c::MuxI2C;
 use capsules::virtual_spi::{MuxSpiMaster, VirtualSpiMasterDevice};
+use capsules::virtual_uart::{UartDevice, UartMux};
 use kernel::component::Component;
 use kernel::hil;
 use kernel::hil::radio;
@@ -94,7 +95,7 @@ static mut PROCESSES: [Option<&'static mut kernel::procs::Process<'static>>; NUM
 pub static mut STACK_MEMORY: [u8; 0x1000] = [0; 0x1000];
 
 struct Imix {
-    console: &'static capsules::console::Console<'static, sam4l::usart::USART>,
+    console: &'static capsules::console::Console<'static, UartDevice<'static>>,
     gpio: &'static capsules::gpio::GPIO<'static, sam4l::gpio::GPIOPin>,
     alarm: &'static AlarmDriver<'static, VirtualMuxAlarm<'static, sam4l::ast::Ast<'static>>>,
     temp: &'static capsules::temperature::TemperatureSensor<'static>,
@@ -254,7 +255,15 @@ pub unsafe fn reset_handler() {
         trng: true,
     });
 
-    let console = ConsoleComponent::new(&sam4l::usart::USART3, 115200).finalize();
+    // Create a shared UART channel for the console and for kernel debug.
+    sam4l::usart::USART3.set_mode(sam4l::usart::UsartMode::Uart);
+    let uart_mux = static_init!(
+        UartMux<'static>,
+        UartMux::new(&sam4l::usart::USART3, &mut capsules::virtual_uart::RX_BUF)
+    );
+    hil::uart::UART::set_client(&sam4l::usart::USART3, uart_mux);
+
+    let console = ConsoleComponent::new(uart_mux, 115200).finalize();
 
     // Allow processes to communicate over BLE through the nRF51822
     let nrf_serialization =

boards/launchxl/src/main.rs

@@ -12,8 +12,10 @@ extern crate cc26xx;
 #[macro_use(debug, debug_gpio, static_init)]
 extern crate kernel;
 
+use capsules::virtual_uart::{UartDevice, UartMux};
 use cc26x2::aon;
 use cc26x2::prcm;
+use kernel::hil;
 
 #[macro_use]
 pub mod io;
@@ -38,7 +40,7 @@ pub static mut STACK_MEMORY: [u8; 0x1000] = [0; 0x1000];
 pub struct Platform {
     gpio: &'static capsules::gpio::GPIO<'static, cc26xx::gpio::GPIOPin>,
     led: &'static capsules::led::LED<'static, cc26xx::gpio::GPIOPin>,
-    console: &'static capsules::console::Console<'static, cc26xx::uart::UART>,
+    console: &'static capsules::console::Console<'static, UartDevice<'static>>,
     button: &'static capsules::button::Button<'static, cc26xx::gpio::GPIOPin>,
     alarm: &'static capsules::alarm::AlarmDriver<
         'static,
@@ -125,23 +127,51 @@ pub unsafe fn reset_handler() {
     }
 
     // UART
+
+    // Create a shared UART channel for the console and for kernel debug.
+    let uart_mux = static_init!(
+        UartMux<'static>,
+        UartMux::new(&cc26xx::uart::UART0, &mut capsules::virtual_uart::RX_BUF)
+    );
+    hil::uart::UART::set_client(&cc26xx::uart::UART0, uart_mux);
+
+    // Create a UartDevice for the console.
+    let console_uart = static_init!(UartDevice, UartDevice::new(uart_mux, true));
+    console_uart.setup();
+
     cc26xx::uart::UART0.initialize_and_set_pins(3, 2);
+
     let console = static_init!(
-        capsules::console::Console<cc26xx::uart::UART>,
+        capsules::console::Console<UartDevice>,
         capsules::console::Console::new(
-            &cc26xx::uart::UART0,
+            console_uart,
             115200,
             &mut capsules::console::WRITE_BUF,
             &mut capsules::console::READ_BUF,
             kernel::Grant::create()
         )
     );
-    kernel::hil::uart::UART::set_client(&cc26xx::uart::UART0, console);
+    kernel::hil::uart::UART::set_client(console_uart, console);
     console.initialize();
 
-    // Attach the kernel debug interface to this console
-    let kc = static_init!(capsules::console::App, capsules::console::App::default());
-    kernel::debug::assign_console_driver(Some(console), kc);
+    // Create virtual device for kernel debug.
+    let debugger_uart = static_init!(UartDevice, UartDevice::new(uart_mux, false));
+    debugger_uart.setup();
+    let debugger = static_init!(
+        kernel::debug::DebugWriter,
+        kernel::debug::DebugWriter::new(
+            debugger_uart,
+            &mut kernel::debug::OUTPUT_BUF,
+            &mut kernel::debug::INTERNAL_BUF,
+        )
+    );
+    hil::uart::UART::set_client(debugger_uart, debugger);
+
+    let debug_wrapper = static_init!(
+        kernel::debug::DebugWriterWrapper,
+        kernel::debug::DebugWriterWrapper::new(debugger)
+    );
+    kernel::debug::set_debug_writer_wrapper(debug_wrapper);
 
     // Setup for remaining GPIO pins
     let gpio_pins = static_init!(