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647 lines
21 KiB
Markdown
647 lines
21 KiB
Markdown
# Tutorial 08 - Timestamps
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## tl;dr
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We add abstractions for the architectural timer, implement it for `aarch64` and use it to annotate
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prints with timestamps; A `warn!()` macro is added.
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## Test it
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Check it out via chainboot (added in previous tutorial):
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```console
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$ make chainboot
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[...]
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Minipush 1.0
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[MP] ⏳ Waiting for /dev/ttyUSB0
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[MP] ✅ Connected
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__ __ _ _ _ _
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| \/ (_)_ _ (_) | ___ __ _ __| |
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| |\/| | | ' \| | |__/ _ \/ _` / _` |
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|_| |_|_|_||_|_|____\___/\__,_\__,_|
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Raspberry Pi 3
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[ML] Requesting binary
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[MP] ⏩ Pushing 12 KiB =========================================🦀 100% 0 KiB/s Time: 00:00:00
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[ML] Loaded! Executing the payload now
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[ 0.586140] Booting on: Raspberry Pi 3
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[ 0.587227] Architectural timer resolution: 52 ns
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[ 0.589530] Drivers loaded:
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[ 0.590876] 1. BCM GPIO
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[ 0.592309] 2. BCM PL011 UART
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[W 0.594005] Spin duration smaller than architecturally supported, skipping
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[ 0.597392] Spinning for 1 second
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[ 1.599001] Spinning for 1 second
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[ 2.599872] Spinning for 1 second
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```
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## Diff to previous
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```diff
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Binary files 07_uart_chainloader/demo_payload_rpi3.img and 08_timestamps/demo_payload_rpi3.img differ
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Binary files 07_uart_chainloader/demo_payload_rpi4.img and 08_timestamps/demo_payload_rpi4.img differ
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diff -uNr 07_uart_chainloader/Makefile 08_timestamps/Makefile
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--- 07_uart_chainloader/Makefile
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+++ 08_timestamps/Makefile
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@@ -19,8 +19,7 @@
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QEMU_MACHINE_TYPE = raspi3
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QEMU_RELEASE_ARGS = -serial stdio -display none
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LINKER_FILE = src/bsp/raspberrypi/link.ld
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- RUSTC_MISC_ARGS = -C target-cpu=cortex-a53 -C relocation-model=pic
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- CHAINBOOT_DEMO_PAYLOAD = demo_payload_rpi3.img
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+ RUSTC_MISC_ARGS = -C target-cpu=cortex-a53
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else ifeq ($(BSP),rpi4)
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TARGET = aarch64-unknown-none-softfloat
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KERNEL_BIN = kernel8.img
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@@ -28,8 +27,7 @@
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QEMU_MACHINE_TYPE =
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QEMU_RELEASE_ARGS = -serial stdio -display none
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LINKER_FILE = src/bsp/raspberrypi/link.ld
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- RUSTC_MISC_ARGS = -C target-cpu=cortex-a72 -C relocation-model=pic
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- CHAINBOOT_DEMO_PAYLOAD = demo_payload_rpi4.img
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+ RUSTC_MISC_ARGS = -C target-cpu=cortex-a72
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endif
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# Export for build.rs
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@@ -69,8 +67,7 @@
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EXEC_QEMU = $(QEMU_BINARY) -M $(QEMU_MACHINE_TYPE)
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EXEC_MINIPUSH = ruby ../utils/minipush.rb
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-.PHONY: all $(KERNEL_ELF) $(KERNEL_BIN) doc qemu qemuasm chainboot clippy clean readelf objdump nm \
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- check
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+.PHONY: all $(KERNEL_ELF) $(KERNEL_BIN) doc qemu chainboot clippy clean readelf objdump nm check
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all: $(KERNEL_BIN)
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@@ -84,18 +81,15 @@
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$(DOC_CMD) --document-private-items --open
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ifeq ($(QEMU_MACHINE_TYPE),)
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-qemu qemuasm:
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+qemu:
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@echo "This board is not yet supported for QEMU."
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else
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qemu: $(KERNEL_BIN)
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@$(DOCKER_QEMU) $(EXEC_QEMU) $(QEMU_RELEASE_ARGS) -kernel $(KERNEL_BIN)
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-
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-qemuasm: $(KERNEL_BIN)
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- @$(DOCKER_QEMU) $(EXEC_QEMU) $(QEMU_RELEASE_ARGS) -kernel $(KERNEL_BIN) -d in_asm
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endif
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-chainboot:
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- @$(DOCKER_CHAINBOOT) $(EXEC_MINIPUSH) $(DEV_SERIAL) $(CHAINBOOT_DEMO_PAYLOAD)
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+chainboot: $(KERNEL_BIN)
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+ @$(DOCKER_CHAINBOOT) $(EXEC_MINIPUSH) $(DEV_SERIAL) $(KERNEL_BIN)
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clippy:
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RUSTFLAGS="$(RUSTFLAGS_PEDANTIC)" $(CLIPPY_CMD)
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diff -uNr 07_uart_chainloader/src/_arch/aarch64/cpu.rs 08_timestamps/src/_arch/aarch64/cpu.rs
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--- 07_uart_chainloader/src/_arch/aarch64/cpu.rs
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+++ 08_timestamps/src/_arch/aarch64/cpu.rs
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@@ -21,12 +21,12 @@
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#[naked]
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#[no_mangle]
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pub unsafe extern "C" fn _start() -> ! {
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- use crate::relocate;
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+ use crate::runtime_init;
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// Expect the boot core to start in EL2.
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if bsp::cpu::BOOT_CORE_ID == cpu::smp::core_id() {
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SP.set(bsp::cpu::BOOT_CORE_STACK_START);
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- relocate::relocate_self::<u64>()
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+ runtime_init::runtime_init()
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} else {
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// If not core0, infinitely wait for events.
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wait_forever()
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diff -uNr 07_uart_chainloader/src/_arch/aarch64/time.rs 08_timestamps/src/_arch/aarch64/time.rs
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--- 07_uart_chainloader/src/_arch/aarch64/time.rs
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+++ 08_timestamps/src/_arch/aarch64/time.rs
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@@ -0,0 +1,101 @@
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+// SPDX-License-Identifier: MIT OR Apache-2.0
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+//
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+// Copyright (c) 2018-2020 Andre Richter <andre.o.richter@gmail.com>
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+
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+//! Architectural timer primitives.
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+
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+use crate::{time, warn};
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+use core::time::Duration;
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+use cortex_a::regs::*;
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+
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+//--------------------------------------------------------------------------------------------------
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+// Private Definitions
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+//--------------------------------------------------------------------------------------------------
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+
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+const NS_PER_S: u64 = 1_000_000_000;
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+
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+//--------------------------------------------------------------------------------------------------
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+// Public Definitions
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+//--------------------------------------------------------------------------------------------------
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+
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+/// ARMv8 Generic Timer.
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+pub struct GenericTimer;
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+
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+//--------------------------------------------------------------------------------------------------
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+// Global instances
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+//--------------------------------------------------------------------------------------------------
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+
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+static TIME_MANAGER: GenericTimer = GenericTimer;
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+
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+//--------------------------------------------------------------------------------------------------
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+// Public Code
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+//--------------------------------------------------------------------------------------------------
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+
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+/// Return a reference to the time manager.
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+pub fn time_manager() -> &'static impl time::interface::TimeManager {
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+ &TIME_MANAGER
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+}
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+
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+//------------------------------------------------------------------------------
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+// OS Interface Code
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+//------------------------------------------------------------------------------
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+
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+impl time::interface::TimeManager for GenericTimer {
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+ fn resolution(&self) -> Duration {
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+ Duration::from_nanos(NS_PER_S / (CNTFRQ_EL0.get() as u64))
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+ }
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+
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+ fn uptime(&self) -> Duration {
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+ let frq: u64 = CNTFRQ_EL0.get() as u64;
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+ let current_count: u64 = CNTPCT_EL0.get() * NS_PER_S;
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+
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+ Duration::from_nanos(current_count / frq)
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+ }
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+
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+ fn spin_for(&self, duration: Duration) {
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+ // Instantly return on zero.
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+ if duration.as_nanos() == 0 {
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+ return;
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+ }
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+
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+ // Calculate the register compare value.
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+ let frq = CNTFRQ_EL0.get() as u64;
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+ let x = match frq.checked_mul(duration.as_nanos() as u64) {
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+ None => {
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+ warn!("Spin duration too long, skipping");
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+ return;
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+ }
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+ Some(val) => val,
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+ };
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+ let tval = x / NS_PER_S;
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+
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+ // Check if it is within supported bounds.
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+ let warn: Option<&str> = if tval == 0 {
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+ Some("smaller")
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+ } else if tval > u32::max_value().into() {
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+ Some("bigger")
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+ } else {
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+ None
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+ };
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+
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+ if let Some(w) = warn {
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+ warn!(
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+ "Spin duration {} than architecturally supported, skipping",
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+ w
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+ );
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+ return;
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+ }
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+
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+ // Set the compare value register.
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+ CNTP_TVAL_EL0.set(tval as u32);
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+
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+ // Kick off the counting. // Disable timer interrupt.
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+ CNTP_CTL_EL0.modify(CNTP_CTL_EL0::ENABLE::SET + CNTP_CTL_EL0::IMASK::SET);
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+
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+ // ISTATUS will be '1' when cval ticks have passed. Busy-check it.
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+ while !CNTP_CTL_EL0.matches_all(CNTP_CTL_EL0::ISTATUS::SET) {}
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+
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+ // Disable counting again.
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+ CNTP_CTL_EL0.modify(CNTP_CTL_EL0::ENABLE::CLEAR);
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+ }
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+}
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diff -uNr 07_uart_chainloader/src/bsp/device_driver/bcm/bcm2xxx_pl011_uart.rs 08_timestamps/src/bsp/device_driver/bcm/bcm2xxx_pl011_uart.rs
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--- 07_uart_chainloader/src/bsp/device_driver/bcm/bcm2xxx_pl011_uart.rs
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+++ 08_timestamps/src/bsp/device_driver/bcm/bcm2xxx_pl011_uart.rs
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@@ -303,11 +303,18 @@
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cpu::nop();
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}
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+ // Read one character.
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+ let mut ret = inner.DR.get() as u8 as char;
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+
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+ // Convert carrige return to newline.
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+ if ret == '\r' {
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+ ret = '\n'
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+ }
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+
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// Update statistics.
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inner.chars_read += 1;
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- // Read one character.
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- inner.DR.get() as u8 as char
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+ ret
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})
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}
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diff -uNr 07_uart_chainloader/src/bsp/raspberrypi/cpu.rs 08_timestamps/src/bsp/raspberrypi/cpu.rs
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--- 07_uart_chainloader/src/bsp/raspberrypi/cpu.rs
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+++ 08_timestamps/src/bsp/raspberrypi/cpu.rs
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@@ -13,6 +13,3 @@
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/// The early boot core's stack address.
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pub const BOOT_CORE_STACK_START: u64 = 0x80_000;
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-
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-/// The address on which the Raspberry firmware loads every binary by default.
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-pub const BOARD_DEFAULT_LOAD_ADDRESS: usize = 0x80_000;
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diff -uNr 07_uart_chainloader/src/bsp/raspberrypi/link.ld 08_timestamps/src/bsp/raspberrypi/link.ld
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--- 07_uart_chainloader/src/bsp/raspberrypi/link.ld
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+++ 08_timestamps/src/bsp/raspberrypi/link.ld
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@@ -5,10 +5,9 @@
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SECTIONS
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{
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- /* Set the link address to 32 MiB */
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- . = 0x2000000;
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+ /* Set current address to the value from which the RPi starts execution */
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+ . = 0x80000;
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- __binary_start = .;
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.text :
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{
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*(.text._start) *(.text*)
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@@ -33,14 +32,5 @@
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__bss_end = .;
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}
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- .got :
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- {
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- *(.got*)
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- }
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-
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- /* Fill up to 8 byte, b/c relocating the binary is done in u64 chunks */
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- . = ALIGN(8);
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- __binary_end = .;
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-
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/DISCARD/ : { *(.comment*) }
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}
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diff -uNr 07_uart_chainloader/src/main.rs 08_timestamps/src/main.rs
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--- 07_uart_chainloader/src/main.rs
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+++ 08_timestamps/src/main.rs
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@@ -11,9 +11,11 @@
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//!
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//! - [`bsp::console::console()`] - Returns a reference to the kernel's [console interface].
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//! - [`bsp::driver::driver_manager()`] - Returns a reference to the kernel's [driver interface].
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+//! - [`time::time_manager()`] - Returns a reference to the kernel's [timer interface].
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//!
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//! [console interface]: ../libkernel/console/interface/index.html
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//! [driver interface]: ../libkernel/driver/interface/trait.DriverManager.html
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+//! [timer interface]: ../libkernel/time/interface/trait.TimeManager.html
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//!
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//! # Code organization and architecture
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//!
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@@ -108,8 +110,7 @@
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#![no_std]
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// `mod cpu` provides the `_start()` function, the first function to run. `_start()` then calls
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-// `relocate::relocate_self()`. `relocate::relocate_self()` calls `runtime_init()`, which jumps to
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-// `kernel_init()`.
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+// `runtime_init()`, which jumps to `kernel_init()`.
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mod bsp;
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mod console;
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@@ -118,9 +119,9 @@
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mod memory;
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mod panic_wait;
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mod print;
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-mod relocate;
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mod runtime_init;
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mod synchronization;
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+mod time;
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/// Early init code.
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///
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@@ -145,52 +146,31 @@
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/// The main function running after the early init.
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fn kernel_main() -> ! {
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- use bsp::console::console;
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- use console::interface::All;
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+ use core::time::Duration;
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+ use driver::interface::DriverManager;
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+ use time::interface::TimeManager;
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- println!(" __ __ _ _ _ _ ");
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- println!("| \\/ (_)_ _ (_) | ___ __ _ __| |");
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- println!("| |\\/| | | ' \\| | |__/ _ \\/ _` / _` |");
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- println!("|_| |_|_|_||_|_|____\\___/\\__,_\\__,_|");
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- println!();
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- println!("{:^37}", bsp::board_name());
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- println!();
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- println!("[ML] Requesting binary");
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- console().flush();
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-
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- // Clear the RX FIFOs, if any, of spurious received characters before starting with the loader
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- // protocol.
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- console().clear();
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-
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- // Notify `Minipush` to send the binary.
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- for _ in 0..3 {
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- console().write_char(3 as char);
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- }
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+ info!("Booting on: {}", bsp::board_name());
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- // Read the binary's size.
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- let mut size: u32 = u32::from(console().read_char() as u8);
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- size |= u32::from(console().read_char() as u8) << 8;
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- size |= u32::from(console().read_char() as u8) << 16;
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- size |= u32::from(console().read_char() as u8) << 24;
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-
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- // Trust it's not too big.
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- console().write_char('O');
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- console().write_char('K');
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-
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- let kernel_addr: *mut u8 = bsp::cpu::BOARD_DEFAULT_LOAD_ADDRESS as *mut u8;
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- unsafe {
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- // Read the kernel byte by byte.
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- for i in 0..size {
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- *kernel_addr.offset(i as isize) = console().read_char() as u8;
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- }
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+ info!(
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+ "Architectural timer resolution: {} ns",
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+ time::time_manager().resolution().as_nanos()
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+ );
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+
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+ info!("Drivers loaded:");
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+ for (i, driver) in bsp::driver::driver_manager()
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+ .all_device_drivers()
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+ .iter()
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+ .enumerate()
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+ {
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+ info!(" {}. {}", i + 1, driver.compatible());
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}
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- println!("[ML] Loaded! Executing the payload now\n");
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- console().flush();
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+ // Test a failing timer case.
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+ time::time_manager().spin_for(Duration::from_nanos(1));
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- // Use black magic to get a function pointer.
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- let kernel: extern "C" fn() -> ! = unsafe { core::mem::transmute(kernel_addr as *const ()) };
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-
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- // Jump to loaded kernel!
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- kernel()
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+ loop {
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+ info!("Spinning for 1 second");
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+ time::time_manager().spin_for(Duration::from_secs(1));
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+ }
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}
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diff -uNr 07_uart_chainloader/src/print.rs 08_timestamps/src/print.rs
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--- 07_uart_chainloader/src/print.rs
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+++ 08_timestamps/src/print.rs
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@@ -40,3 +40,71 @@
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$crate::print::_print(format_args_nl!($($arg)*));
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})
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}
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+
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+/// Prints an info, with a newline.
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+#[macro_export]
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+macro_rules! info {
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+ ($string:expr) => ({
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+ #[allow(unused_imports)]
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+ use crate::time::interface::TimeManager;
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+
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+ let timestamp = $crate::time::time_manager().uptime();
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+ let timestamp_subsec_us = timestamp.subsec_micros();
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+
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+ $crate::print::_print(format_args_nl!(
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+ concat!("[ {:>3}.{:03}{:03}] ", $string),
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+ timestamp.as_secs(),
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+ timestamp_subsec_us / 1_000,
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+ timestamp_subsec_us modulo 1_000
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+ ));
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+ });
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+ ($format_string:expr, $($arg:tt)*) => ({
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+ #[allow(unused_imports)]
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+ use crate::time::interface::TimeManager;
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+
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+ let timestamp = $crate::time::time_manager().uptime();
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+ let timestamp_subsec_us = timestamp.subsec_micros();
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+
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+ $crate::print::_print(format_args_nl!(
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+ concat!("[ {:>3}.{:03}{:03}] ", $format_string),
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+ timestamp.as_secs(),
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+ timestamp_subsec_us / 1_000,
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+ timestamp_subsec_us modulo 1_000,
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+ $($arg)*
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+ ));
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+ })
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+}
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+
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+/// Prints a warning, with a newline.
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+#[macro_export]
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+macro_rules! warn {
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+ ($string:expr) => ({
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+ #[allow(unused_imports)]
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+ use crate::time::interface::TimeManager;
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+
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+ let timestamp = $crate::time::time_manager().uptime();
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+ let timestamp_subsec_us = timestamp.subsec_micros();
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+
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+ $crate::print::_print(format_args_nl!(
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+ concat!("[W {:>3}.{:03}{:03}] ", $string),
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+ timestamp.as_secs(),
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+ timestamp_subsec_us / 1_000,
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+ timestamp_subsec_us modulo 1_000
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+ ));
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+ });
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+ ($format_string:expr, $($arg:tt)*) => ({
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+ #[allow(unused_imports)]
|
|
+ use crate::time::interface::TimeManager;
|
|
+
|
|
+ let timestamp = $crate::time::time_manager().uptime();
|
|
+ let timestamp_subsec_us = timestamp.subsec_micros();
|
|
+
|
|
+ $crate::print::_print(format_args_nl!(
|
|
+ concat!("[W {:>3}.{:03}{:03}] ", $format_string),
|
|
+ timestamp.as_secs(),
|
|
+ timestamp_subsec_us / 1_000,
|
|
+ timestamp_subsec_us modulo 1_000,
|
|
+ $($arg)*
|
|
+ ));
|
|
+ })
|
|
+}
|
|
|
|
diff -uNr 07_uart_chainloader/src/relocate.rs 08_timestamps/src/relocate.rs
|
|
--- 07_uart_chainloader/src/relocate.rs
|
|
+++ 08_timestamps/src/relocate.rs
|
|
@@ -1,52 +0,0 @@
|
|
-// SPDX-License-Identifier: MIT OR Apache-2.0
|
|
-//
|
|
-// Copyright (c) 2018-2020 Andre Richter <andre.o.richter@gmail.com>
|
|
-
|
|
-//! Relocation code.
|
|
-
|
|
-use crate::{bsp, runtime_init};
|
|
-
|
|
-//--------------------------------------------------------------------------------------------------
|
|
-// Public Code
|
|
-//--------------------------------------------------------------------------------------------------
|
|
-
|
|
-/// Relocates the own binary from `bsp::cpu::BOARD_DEFAULT_LOAD_ADDRESS` to the `__binary_start`
|
|
-/// address from the linker script.
|
|
-///
|
|
-/// # Safety
|
|
-///
|
|
-/// - Only a single core must be active and running this function.
|
|
-/// - Function must not use the `bss` section.
|
|
-pub unsafe fn relocate_self<T>() -> ! {
|
|
- extern "C" {
|
|
- static __binary_start: usize;
|
|
- static __binary_end: usize;
|
|
- }
|
|
-
|
|
- let binary_start_addr: usize = &__binary_start as *const _ as _;
|
|
- let binary_end_addr: usize = &__binary_end as *const _ as _;
|
|
- let binary_size_in_byte: usize = binary_end_addr - binary_start_addr;
|
|
-
|
|
- // Get the relocation destination address from the linker symbol.
|
|
- let mut reloc_dst_addr: *mut T = binary_start_addr as *mut T;
|
|
-
|
|
- // The address of where the previous firmware loaded us.
|
|
- let mut src_addr: *const T = bsp::cpu::BOARD_DEFAULT_LOAD_ADDRESS as *const _;
|
|
-
|
|
- // Copy the whole binary.
|
|
- //
|
|
- // This is essentially a `memcpy()` optimized for throughput by transferring in chunks of T.
|
|
- let n = binary_size_in_byte / core::mem::size_of::<T>();
|
|
- for _ in 0..n {
|
|
- use core::ptr;
|
|
-
|
|
- ptr::write_volatile::<T>(reloc_dst_addr, ptr::read_volatile::<T>(src_addr));
|
|
- reloc_dst_addr = reloc_dst_addr.offset(1);
|
|
- src_addr = src_addr.offset(1);
|
|
- }
|
|
-
|
|
- // Call `runtime_init()` through a trait object, causing the jump to use an absolute address to
|
|
- // reach the relocated binary. An elaborate explanation can be found in the `runtime_init.rs`
|
|
- // source comments.
|
|
- runtime_init::get().runtime_init()
|
|
-}
|
|
|
|
diff -uNr 07_uart_chainloader/src/runtime_init.rs 08_timestamps/src/runtime_init.rs
|
|
--- 07_uart_chainloader/src/runtime_init.rs
|
|
+++ 08_timestamps/src/runtime_init.rs
|
|
@@ -8,43 +8,9 @@
|
|
use core::ops::Range;
|
|
|
|
//--------------------------------------------------------------------------------------------------
|
|
-// Private Definitions
|
|
-//--------------------------------------------------------------------------------------------------
|
|
-
|
|
-struct Traitor;
|
|
-
|
|
-//--------------------------------------------------------------------------------------------------
|
|
-// Public Definitions
|
|
-//--------------------------------------------------------------------------------------------------
|
|
-
|
|
-/// We are outsmarting the compiler here by using a trait as a layer of indirection. Because we are
|
|
-/// generating PIC code, a static dispatch to `init()` would generate a relative jump from the
|
|
-/// callee to `init()`. However, when calling `init()`, code just finished copying the binary to the
|
|
-/// actual link-time address, and hence is still running at whatever location the previous loader
|
|
-/// has put it. So we do not want a relative jump, because it would not jump to the relocated code.
|
|
-///
|
|
-/// By indirecting through a trait object, we can make use of the property that vtables store
|
|
-/// absolute addresses. So calling `init()` this way will kick execution to the relocated binary.
|
|
-pub trait RunTimeInit {
|
|
- /// Equivalent to `crt0` or `c0` code in C/C++ world. Clears the `bss` section, then jumps to
|
|
- /// kernel init code.
|
|
- ///
|
|
- /// # Safety
|
|
- ///
|
|
- /// - Only a single core must be active and running this function.
|
|
- unsafe fn runtime_init(&self) -> ! {
|
|
- zero_bss();
|
|
-
|
|
- crate::kernel_init()
|
|
- }
|
|
-}
|
|
-
|
|
-//--------------------------------------------------------------------------------------------------
|
|
// Private Code
|
|
//--------------------------------------------------------------------------------------------------
|
|
|
|
-impl RunTimeInit for Traitor {}
|
|
-
|
|
/// Return the range spanning the .bss section.
|
|
///
|
|
/// # Safety
|
|
@@ -78,7 +44,14 @@
|
|
// Public Code
|
|
//--------------------------------------------------------------------------------------------------
|
|
|
|
-/// Give the callee a `RunTimeInit` trait object.
|
|
-pub fn get() -> &'static dyn RunTimeInit {
|
|
- &Traitor {}
|
|
+/// Equivalent to `crt0` or `c0` code in C/C++ world. Clears the `bss` section, then jumps to kernel
|
|
+/// init code.
|
|
+///
|
|
+/// # Safety
|
|
+///
|
|
+/// - Only a single core must be active and running this function.
|
|
+pub unsafe fn runtime_init() -> ! {
|
|
+ zero_bss();
|
|
+
|
|
+ crate::kernel_init()
|
|
}
|
|
|
|
diff -uNr 07_uart_chainloader/src/time.rs 08_timestamps/src/time.rs
|
|
--- 07_uart_chainloader/src/time.rs
|
|
+++ 08_timestamps/src/time.rs
|
|
@@ -0,0 +1,35 @@
|
|
+// SPDX-License-Identifier: MIT OR Apache-2.0
|
|
+//
|
|
+// Copyright (c) 2020 Andre Richter <andre.o.richter@gmail.com>
|
|
+
|
|
+//! Timer primitives.
|
|
+
|
|
+#[cfg(target_arch = "aarch64")]
|
|
+#[path = "_arch/aarch64/time.rs"]
|
|
+mod arch_time;
|
|
+pub use arch_time::*;
|
|
+
|
|
+//--------------------------------------------------------------------------------------------------
|
|
+// Public Definitions
|
|
+//--------------------------------------------------------------------------------------------------
|
|
+
|
|
+/// Timekeeping interfaces.
|
|
+pub mod interface {
|
|
+ use core::time::Duration;
|
|
+
|
|
+ /// Time management functions.
|
|
+ ///
|
|
+ /// The `BSP` is supposed to supply one global instance.
|
|
+ pub trait TimeManager {
|
|
+ /// The timer's resolution.
|
|
+ fn resolution(&self) -> Duration;
|
|
+
|
|
+ /// The uptime since power-on of the device.
|
|
+ ///
|
|
+ /// This includes time consumed by firmware and bootloaders.
|
|
+ fn uptime(&self) -> Duration;
|
|
+
|
|
+ /// Spin for a given duration.
|
|
+ fn spin_for(&self, duration: Duration);
|
|
+ }
|
|
+}
|
|
|
|
```
|