Introduce the PanicWriter trait, a standard mechanism for implementing synchronous writers for panic messages

boards/apollo3/lora_things_plus/src/io.rs

@@ -2,35 +2,11 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 // Copyright Tock Contributors 2022.
 
-use core::fmt::Write;
 use core::panic::PanicInfo;
-use core::ptr::addr_of_mut;
 
 use kernel::debug;
-use kernel::debug::IoWrite;
 use kernel::hil::led;
 
-/// Writer is used by kernel::debug to panic message to the serial port.
-pub struct Writer {}
-
-/// Global static for debug writer
-pub static mut WRITER: Writer = Writer {};
-
-impl Write for Writer {
-    fn write_str(&mut self, s: &str) -> ::core::fmt::Result {
-        self.write(s.as_bytes());
-        Ok(())
-    }
-}
-
-impl IoWrite for Writer {
-    fn write(&mut self, buf: &[u8]) -> usize {
-        let uart = apollo3::uart::Uart::new_uart_0(); // Aliases memory for uart0. Okay bc we are panicking.
-        uart.transmit_sync(buf);
-        buf.len()
-    }
-}
-
 /// Panic handler.
 #[panic_handler]
 pub unsafe fn panic_fmt(info: &PanicInfo) -> ! {
@@ -42,11 +18,20 @@ pub unsafe fn panic_fmt(info: &PanicInfo) -> ! {
         apollo3::gpio::Pin::Pin26,
     );
     let led = &mut led::LedLow::new(led_pin);
-    let writer = &mut *addr_of_mut!(WRITER);
 
-    debug::panic(
+    debug::panic::<_, apollo3::uart::Uart, _, _>(
         &mut [led],
-        writer,
+        apollo3::uart::UartPanicWriterConfig {
+            params: kernel::hil::uart::Parameters {
+                baud_rate: 115200,
+                stop_bits: kernel::hil::uart::StopBits::One,
+                parity: kernel::hil::uart::Parity::None,
+                hw_flow_control: false,
+                width: kernel::hil::uart::Width::Eight,
+            },
+            tx_pin_index: 48,
+            rx_pin_index: 49,
+        },
         info,
         &cortexm4::support::nop,
         crate::PANIC_RESOURCES.get(),

boards/apollo3/redboard_artemis_atp/src/io.rs

@@ -2,35 +2,11 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 // Copyright Tock Contributors 2022.
 
-use core::fmt::Write;
 use core::panic::PanicInfo;
-use core::ptr::addr_of_mut;
 
 use kernel::debug;
-use kernel::debug::IoWrite;
 use kernel::hil::led;
 
-/// Writer is used by kernel::debug to panic message to the serial port.
-pub struct Writer {}
-
-/// Global static for debug writer
-pub static mut WRITER: Writer = Writer {};
-
-impl Write for Writer {
-    fn write_str(&mut self, s: &str) -> ::core::fmt::Result {
-        self.write(s.as_bytes());
-        Ok(())
-    }
-}
-
-impl IoWrite for Writer {
-    fn write(&mut self, buf: &[u8]) -> usize {
-        let uart = apollo3::uart::Uart::new_uart_0(); // Aliases memory for uart0. Okay bc we are panicking.
-        uart.transmit_sync(buf);
-        buf.len()
-    }
-}
-
 /// Panic handler.
 #[panic_handler]
 pub unsafe fn panic_fmt(info: &PanicInfo) -> ! {
@@ -42,11 +18,20 @@ pub unsafe fn panic_fmt(info: &PanicInfo) -> ! {
         apollo3::gpio::Pin::Pin19,
     );
     let led = &mut led::LedLow::new(led_pin);
-    let writer = &mut *addr_of_mut!(WRITER);
 
-    debug::panic(
+    debug::panic::<_, apollo3::uart::Uart, _, _>(
         &mut [led],
-        writer,
+        apollo3::uart::UartPanicWriterConfig {
+            params: kernel::hil::uart::Parameters {
+                baud_rate: 115200,
+                stop_bits: kernel::hil::uart::StopBits::One,
+                parity: kernel::hil::uart::Parity::None,
+                hw_flow_control: false,
+                width: kernel::hil::uart::Width::Eight,
+            },
+            tx_pin_index: 48,
+            rx_pin_index: 49,
+        },
         info,
         &cortexm4::support::nop,
         crate::PANIC_RESOURCES.get(),

boards/apollo3/redboard_artemis_nano/src/io.rs

@@ -2,35 +2,11 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 // Copyright Tock Contributors 2022.
 
-use core::fmt::Write;
 use core::panic::PanicInfo;
-use core::ptr::addr_of_mut;
 
 use kernel::debug;
-use kernel::debug::IoWrite;
 use kernel::hil::led;
 
-/// Writer is used by kernel::debug to panic message to the serial port.
-pub struct Writer {}
-
-/// Global static for debug writer
-pub static mut WRITER: Writer = Writer {};
-
-impl Write for Writer {
-    fn write_str(&mut self, s: &str) -> ::core::fmt::Result {
-        self.write(s.as_bytes());
-        Ok(())
-    }
-}
-
-impl IoWrite for Writer {
-    fn write(&mut self, buf: &[u8]) -> usize {
-        let uart = apollo3::uart::Uart::new_uart_0(); // Aliases memory for uart0. Okay bc we are panicking.
-        uart.transmit_sync(buf);
-        buf.len()
-    }
-}
-
 /// Panic handler.
 #[panic_handler]
 pub unsafe fn panic_fmt(info: &PanicInfo) -> ! {
@@ -42,11 +18,20 @@ pub unsafe fn panic_fmt(info: &PanicInfo) -> ! {
         apollo3::gpio::Pin::Pin19,
     );
     let led = &mut led::LedLow::new(led_pin);
-    let writer = &mut *addr_of_mut!(WRITER);
 
-    debug::panic(
+    debug::panic::<_, apollo3::uart::Uart, _, _>(
         &mut [led],
-        writer,
+        apollo3::uart::UartPanicWriterConfig {
+            params: kernel::hil::uart::Parameters {
+                baud_rate: 115200,
+                stop_bits: kernel::hil::uart::StopBits::One,
+                parity: kernel::hil::uart::Parity::None,
+                hw_flow_control: false,
+                width: kernel::hil::uart::Width::Eight,
+            },
+            tx_pin_index: 48,
+            rx_pin_index: 49,
+        },
         info,
         &cortexm4::support::nop,
         crate::PANIC_RESOURCES.get(),

boards/arty_e21/src/io.rs

@@ -2,32 +2,12 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 // Copyright Tock Contributors 2022.
 
-use core::fmt::Write;
 use core::panic::PanicInfo;
 use core::str;
 use kernel::debug;
-use kernel::debug::IoWrite;
 use kernel::hil::gpio;
 use kernel::hil::led;
 
-struct Writer {}
-
-static mut WRITER: Writer = Writer {};
-
-impl Write for Writer {
-    fn write_str(&mut self, s: &str) -> ::core::fmt::Result {
-        self.write(s.as_bytes());
-        Ok(())
-    }
-}
-
-impl IoWrite for Writer {
-    fn write(&mut self, buf: &[u8]) -> usize {
-        sifive::uart::Uart::new(arty_e21_chip::uart::UART0_BASE, 32_000_000).transmit_sync(buf);
-        buf.len()
-    }
-}
-
 /// Panic handler.
 #[cfg(not(test))]
 #[panic_handler]
@@ -59,10 +39,20 @@ pub unsafe fn panic_fmt(pi: &PanicInfo) -> ! {
     );
 
     let led_red = &mut led::LedHigh::new(led_red_pin);
-    let writer = &mut *core::ptr::addr_of_mut!(WRITER);
-    debug::panic(
+
+    debug::panic::<_, sifive::uart::Uart, _, _>(
         &mut [led_red],
-        writer,
+        sifive::uart::UartPanicWriterConfig {
+            registers: arty_e21_chip::uart::UART0_BASE,
+            clock_frequency: 32_000_000,
+            params: kernel::hil::uart::Parameters {
+                baud_rate: 115200,
+                stop_bits: kernel::hil::uart::StopBits::One,
+                parity: kernel::hil::uart::Parity::None,
+                hw_flow_control: false,
+                width: kernel::hil::uart::Width::Eight,
+            },
+        },
         pi,
         &rv32i::support::nop,
         crate::PANIC_RESOURCES.get(),

boards/nordic/nrf52_components/src/startup.rs

@@ -219,10 +219,10 @@ impl Component for UartChannelComponent {
             UartChannel::Pins(uart_pins) => {
                 unsafe {
                     self.uarte0.initialize(
-                        nrf52::pinmux::Pinmux::new(uart_pins.txd as u32),
-                        nrf52::pinmux::Pinmux::new(uart_pins.rxd as u32),
-                        uart_pins.cts.map(|x| nrf52::pinmux::Pinmux::new(x as u32)),
-                        uart_pins.rts.map(|x| nrf52::pinmux::Pinmux::new(x as u32)),
+                        nrf52::pinmux::Pinmux::new(uart_pins.txd),
+                        nrf52::pinmux::Pinmux::new(uart_pins.rxd),
+                        uart_pins.cts.map(|x| nrf52::pinmux::Pinmux::new(x)),
+                        uart_pins.rts.map(|x| nrf52::pinmux::Pinmux::new(x)),
                     )
                 };
                 self.uarte0

boards/nordic/nrf52dk/src/io.rs

@@ -2,67 +2,35 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 // Copyright Tock Contributors 2022.
 
-use core::fmt::Write;
 use core::panic::PanicInfo;
 use kernel::debug;
-use kernel::debug::IoWrite;
 use kernel::hil::led;
-use kernel::hil::uart::{self, Configure};
+use kernel::hil::uart;
 use nrf52832::gpio::Pin;
-use nrf52832::uart::{Uarte, UARTE0_BASE};
-
-struct Writer {
-    initialized: bool,
-}
-
-static mut WRITER: Writer = Writer { initialized: false };
-
-impl Write for Writer {
-    fn write_str(&mut self, s: &str) -> ::core::fmt::Result {
-        self.write(s.as_bytes());
-        Ok(())
-    }
-}
-
-impl IoWrite for Writer {
-    fn write(&mut self, buf: &[u8]) -> usize {
-        // Here, we create a second instance of the Uarte struct.
-        // This is okay because we only call this during a panic, and
-        // we will never actually process the interrupts
-        let uart = Uarte::new(UARTE0_BASE);
-        if !self.initialized {
-            self.initialized = true;
-            let _ = uart.configure(uart::Parameters {
-                baud_rate: 115200,
-                stop_bits: uart::StopBits::One,
-                parity: uart::Parity::None,
-                hw_flow_control: false,
-                width: uart::Width::Eight,
-            });
-        }
-        for &c in buf {
-            unsafe {
-                uart.send_byte(c);
-            }
-            while !uart.tx_ready() {}
-        }
-        buf.len()
-    }
-}
 
 #[cfg(not(test))]
 #[panic_handler]
 /// Panic handler
 pub unsafe fn panic_fmt(pi: &PanicInfo) -> ! {
     // The nRF52 DK LEDs (see back of board)
-
-    use core::ptr::addr_of_mut;
     let led_kernel_pin = &nrf52832::gpio::GPIOPin::new(Pin::P0_17);
     let led = &mut led::LedLow::new(led_kernel_pin);
-    let writer = &mut *addr_of_mut!(WRITER);
-    debug::panic(
+
+    debug::panic::<_, nrf52832::uart::Uarte, _, _>(
         &mut [led],
-        writer,
+        nrf52832::uart::UartPanicWriterConfig {
+            params: uart::Parameters {
+                baud_rate: 115200,
+                stop_bits: uart::StopBits::One,
+                parity: uart::Parity::None,
+                hw_flow_control: false,
+                width: uart::Width::Eight,
+            },
+            txd: crate::UART_TXD,
+            rxd: crate::UART_RXD,
+            cts: crate::UART_CTS,
+            rts: crate::UART_CTS,
+        },
         pi,
         &cortexm4::support::nop,
         crate::PANIC_RESOURCES.get(),