[Cross PR with e310x-hal]: Example of the virq feature and helpful debug configs

.cargo/config.toml

@@ -0,0 +1,9 @@
+[target.'cfg(all(target_arch = "riscv32", target_os = "none"))']
+runner = "qemu-system-riscv32 -machine sifive_e,revb=true -nographic -kernel"
+# runner = "riscv64-unknown-elf-gdb -q -x gdb_init"
+rustflags = [
+  "-C", "link-arg=-Thifive1-link.x",
+]
+
+[build]
+target = "riscv32imac-unknown-none-elf"

.gitignore

@@ -1,4 +1,6 @@
 Cargo.lock
 target/
 core
-.gdb_history
+.gdb_history
+.vscode/.cortex-debug.peripherals.state.json
+.vscode/.cortex-debug.registers.state.json

.vscode/launch.json

@@ -0,0 +1,27 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Hifive1 (Debug)",
+            // Substitute with the board number
+            "device": "FE310", 
+            "type": "cortex-debug",
+            "preLaunchTask": "example-virq",
+            // Defined in tasks.json
+            "request": "launch",
+            "servertype": "jlink",
+            // JLink server path
+            // "serverpath": "",
+            // GDB debug output
+            // "showDevDebugOutput": "raw",
+            "cwd": "${workspaceRoot}",
+            // Executable to launch
+            "executable": "${workspaceRoot}/target/riscv32imac-unknown-none-elf/debug/examples/virq",
+            "interface": "jtag",
+            "svdFile": "${workspaceRoot}/hifive.svd",
+            // Set this to point to sifive risc-v gdb path 
+            "gdbPath": "${workspaceRoot}/../../Toolchains/sifive/bin/riscv64-unknown-elf-gdb",
+            "toolchainPrefix": "riscv64-unknown-elf",
+        },
+    ]
+}

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "cortex-debug.variableUseNaturalFormat": true,
+    "rust-analyzer.cargo.features": ["board-redv"],
+    "rust-analyzer.check.allTargets": false,
+}

.vscode/tasks.json

@@ -0,0 +1,21 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "example-virq",
+            "command": "cargo",
+            "args": [
+                "build",
+                 "--features=board-redv,virq",
+                 "--example=virq"
+            ],
+            "problemMatcher": [
+                "$rustc"
+            ],
+            "group": {
+                "kind": "build",
+                "isDefault": true
+            }
+        },
+    ]
+}

Cargo.toml

@@ -7,20 +7,23 @@ categories = ["embedded", "hardware-support", "no-std"]
 description = "Board support crate for HiFive1 and LoFive boards"
 keywords = ["riscv", "register", "peripheral"]
 license = "ISC"
-edition = "2018"
+edition = "2021"
 
 [dependencies]
-e310x-hal = "0.9.1"
+e310x-hal = {git = "https://github.com/greenlsi/e310x-hal"}
 embedded-hal = "0.2.5"
-riscv = "0.6.0"
+riscv = { version = "0.12.0", features = ["critical-section-single-hart"]}
+riscv-rt = "0.13.0"
 nb = "1.0.0"
+panic-halt = "0.2.0"
 
 [features]
 board-hifive1 = []
 board-hifive1-revb = ["e310x-hal/g002"]
 board-redv = ["e310x-hal/g002"]
 board-lofive = []
 board-lofive-r1 = ["e310x-hal/g002"]
+v-trap = ["e310x-hal/v-trap"]
 
 [package.metadata.docs.rs]
 features = ['board-hifive1-revb']

build.rs

@@ -44,10 +44,4 @@ fn main() {
 
     fs::copy("hifive1-link.x", out_dir.join("hifive1-link.x")).unwrap();
     println!("cargo:rerun-if-changed=hifive1-link.x");
-
-    // Copy library with flash setup code
-    let name = env::var("CARGO_PKG_NAME").unwrap();
-    fs::copy("bin/flash.a", out_dir.join(format!("lib{}.a", name))).unwrap();
-    println!("cargo:rustc-link-lib=static={}", name);
-    println!("cargo:rerun-if-changed=bin/flash.a");
 }

examples/gpio4.rs

@@ -0,0 +1,78 @@
+//! Demonstration on how to configure the GPIO4 interrupt on HiFive boards.
+//! You must connect a button to pin 12 (GPIO4) and ground to test this example.
+
+#![no_main]
+#![no_std]
+
+extern crate panic_halt;
+
+use hifive1::hal::e310x::PLIC;
+use hifive1::{hal::prelude::*, hal::DeviceResources, pin, sprintln};
+
+use riscv::register::mstatus;
+use riscv_rt::entry;
+
+/* Handler for the GPIO0 interrupt */
+#[riscv_rt::external_interrupt(ExternalInterrupt::GPIO4)]
+fn gpio4_handler() {
+    sprintln!("We reached the GPIO4 interrupt!");
+    /* Clear the GPIO pending interrupt */
+    let gpio_block = unsafe { hifive1::hal::e310x::Gpio0::steal() };
+    gpio_block.fall_ip().write(|w| w.pin4().set_bit());
+}
+
+/* Code adapted from https://github.com/riscv-rust/riscv-rust-quickstart/blob/interrupt-test/examples/interrupt.rs*/
+#[entry]
+fn main() -> ! {
+    /* Get the ownership of the device resources singleton */
+    let resources = DeviceResources::take().unwrap();
+    let peripherals = resources.peripherals;
+
+    /* Configure system clock */
+    let sysclock = hifive1::configure_clocks(peripherals.PRCI, peripherals.AONCLK, 64.mhz().into());
+    /* Get the board pins */
+    let gpio = resources.pins;
+
+    /* Configure stdout for debugging */
+    hifive1::stdout::configure(
+        peripherals.UART0,
+        pin!(gpio, uart0_tx),
+        pin!(gpio, uart0_rx),
+        115_200.bps(),
+        sysclock,
+    );
+
+    sprintln!("Configuring GPIO...");
+    /* Set GPIO4 (pin 12) as input */
+    // let gpio4 = pin!(gpio, dig12);
+    gpio.pin4.into_pull_up_input();
+    //let input = gpio4.into_pull_up_input();
+
+    sprintln!("Configuring priorities...");
+    /* Set interrupt source priority */
+    let priorities = PLIC::priorities();
+    unsafe { priorities.set_priority(ExternalInterrupt::GPIO4, Priority::P7) };
+
+    let gpio_block = unsafe { hifive1::hal::e310x::Gpio0::steal() };
+    unsafe {
+        /* Clear pending interrupts from previous states */
+        gpio_block.fall_ie().write(|w| w.bits(0x00000000));
+        gpio_block.rise_ie().write(|w| w.bits(0x00000000));
+        gpio_block.fall_ip().write(|w| w.bits(0xffffffff));
+        gpio_block.rise_ip().write(|w| w.bits(0xffffffff));
+    }
+    gpio_block.fall_ie().write(|w| w.pin4().set_bit());
+    gpio_block.rise_ie().write(|w| w.pin4().clear_bit());
+
+    /* Activate global interrupts (mie bit) */
+    let ctx = PLIC::ctx0();
+    unsafe {
+        ctx.threshold().set_threshold(Priority::P1);
+        ctx.enables().enable(ExternalInterrupt::GPIO4);
+        mstatus::set_mie();
+        PLIC::enable();
+    }
+    loop {
+        riscv::asm::wfi();
+    }
+}

examples/mtimer.rs

@@ -0,0 +1,61 @@
+//! This example demonstrates how to configure the CLINT to generate
+//! periodic interrupts using the machine timer.
+
+#![no_main]
+#![no_std]
+
+extern crate panic_halt;
+
+use hifive1::{
+    configure_clocks,
+    hal::{e310x::CLINT, prelude::*, DeviceResources},
+    pin, sprintln,
+};
+
+const PERIOD_MS: u64 = 1000;
+const FREQUENCY_HZ: u64 = 32768;
+const CLINT_TICKS_PER_MS: u64 = PERIOD_MS * FREQUENCY_HZ / 1000;
+
+/// Handler for the machine timer interrupt (handled by the CLINT)
+#[riscv_rt::core_interrupt(CoreInterrupt::MachineTimer)]
+fn mtimer_handler() {
+    sprintln!("MTIMER interrupt!");
+    CLINT::mtimecmp0().modify(|f| *f += CLINT_TICKS_PER_MS);
+}
+
+#[riscv_rt::entry]
+fn main() -> ! {
+    /* Get the ownership of the device resources singleton */
+    let resources = DeviceResources::take().unwrap();
+    let peripherals = resources.peripherals;
+
+    /* Configure system clock */
+    let sysclock = configure_clocks(peripherals.PRCI, peripherals.AONCLK, 64.mhz().into());
+
+    /* Configure stdout for printing via UART */
+    let gpio = resources.pins;
+    hifive1::stdout::configure(
+        peripherals.UART0,
+        pin!(gpio, uart0_tx),
+        pin!(gpio, uart0_rx),
+        115_200.bps(),
+        sysclock,
+    );
+
+    sprintln!("Configuring CLINT...");
+    CLINT::mtimer_disable();
+    let mtimer = CLINT::mtimer();
+    let (mtimecmp, mtime) = (mtimer.mtimecmp0, mtimer.mtime);
+    mtime.write(0);
+    mtimecmp.write(CLINT_TICKS_PER_MS);
+
+    sprintln!("Enabling interrupts...");
+    unsafe {
+        riscv::interrupt::enable();
+        CLINT::mtimer_enable();
+    }
+    loop {
+        sprintln!("Sleeping...");
+        riscv::asm::wfi();
+    }
+}

gdb_init

@@ -0,0 +1,9 @@
+set history save on
+set confirm off
+set remotetimeout 240
+target extended-remote :3333
+set print asm-demangle on
+monitor reset halt
+load
+continue
+# quit