Add global HSEM object and shared memory sample (#6)

* Core0 controls blink freq of Core1

* Minor code clean-up

.zed/settings.json

@@ -10,6 +10,11 @@
           "allTargets": false,
           "targets": "thumbv7em-none-eabihf"
         },
+        "linkedProjects": [
+          "./core0/Cargo.toml",
+          "./core1/Cargo.toml",
+          "./stm32h7hal-ext/Cargo.toml"
+        ],
         "inlayHints": {
           "maxLength": null,
           "lifetimeElisionHints": {

.zed/tasks.json

@@ -0,0 +1,37 @@
+// Static tasks configuration.
+[
+  {
+    "label": "Build Core 0",
+    "command": "cargo build",
+    //"args": ["build"],
+    // Env overrides for the command, will be appended to the terminal's environment from the settings.
+    // "env": { "foo": "bar" },
+    // Current working directory to spawn the command into, defaults to current project root.
+    "cwd": "$ZED_WORKTREE_ROOT/core0",
+    // Whether to use a new terminal tab or reuse the existing one to spawn the process, defaults to `false`.
+    "use_new_terminal": false,
+    // Whether to allow multiple instances of the same task to be run, or rather wait for the existing ones to finish, defaults to `false`.
+    "allow_concurrent_runs": false
+    // What to do with the terminal pane and tab, after the command was started:
+    // * `always` — always show the terminal pane, add and focus the corresponding task's tab in it (default)
+    // * `never` — avoid changing current terminal pane focus, but still add/reuse the task's tab there
+    //"reveal": "always"
+  },
+  {
+    "label": "Build Core 1",
+    "command": "cargo build",
+    //"args": ["build"],
+    // Env overrides for the command, will be appended to the terminal's environment from the settings.
+    // "env": { "foo": "bar" },
+    // Current working directory to spawn the command into, defaults to current project root.
+    "cwd": "$ZED_WORKTREE_ROOT/core1",
+    // Whether to use a new terminal tab or reuse the existing one to spawn the process, defaults to `false`.
+    "use_new_terminal": false,
+    // Whether to allow multiple instances of the same task to be run, or rather wait for the existing ones to finish, defaults to `false`.
+    "allow_concurrent_runs": false
+    // What to do with the terminal pane and tab, after the command was started:
+    // * `always` — always show the terminal pane, add and focus the corresponding task's tab in it (default)
+    // * `never` — avoid changing current terminal pane focus, but still add/reuse the task's tab there
+    //"reveal": "always"
+  }
+]

core0/Cargo.toml

@@ -53,6 +53,8 @@ embedded-storage = "0.3.1"
 static_cell = "2"
 chrono = { version = "^0.4", default-features = false }
 stm32h7hal-ext = { version = "0.1.0", path = "../stm32h7hal-ext" }
+shared = { version = "0.1.0", path = "../shared" }
+
 # [patch."https://github.com/esrlabs/embassy"]
 # embassy-stm32 = { path = "../../embassy/embassy-stm32" }
 # embassy-sync = { path = "../../embassy/embassy-sync" }

core0/memory.x

@@ -30,8 +30,8 @@ SECTIONS {
     *(.sram3 .sram3.*);
     . = ALIGN(4);
     } > SRAM3
-  .sram4 (NOLOAD) : ALIGN(4) {
-    *(.sram4 .sram4.*);
+  .shared (NOLOAD) : ALIGN(4) {
+    *(.sram4 .sram4.* .shared .shared.*);
     . = ALIGN(4);
     } > SRAM4
   .bsram (NOLOAD) : ALIGN(4) {

core0/src/main.rs

@@ -1,6 +1,7 @@
 #![no_std]
 #![no_main]
-
+#![feature(sync_unsafe_cell)]
+use core::cell::SyncUnsafeCell;
 use cortex_m::peripheral::NVIC;
 use defmt::*;
 use embassy_executor::Spawner;
@@ -9,20 +10,32 @@ use hal::{
     bind_interrupts,
     gpio::{Level, Output, Speed},
     hsem::{HardwareSemaphore, InterruptHandler},
-    peripherals, Config,
+    peripherals::{self, HSEM},
+    Config,
+};
+use {
+    defmt_rtt as _, embassy_stm32 as hal, panic_probe as _, shared as _, stm32h7hal_ext as hal_ext,
 };
-use {defmt_rtt as _, embassy_stm32 as hal, panic_probe as _, stm32h7hal_ext as hal_ext};
 
 bind_interrupts!(
     struct Irqs {
         HSEM1 => InterruptHandler<peripherals::HSEM>;
     }
 );
 
+// SAFETY: This is safe because all access to the HSEM registers are atomic
+static HSEM_INSTANCE: SyncUnsafeCell<Option<HardwareSemaphore<'static, HSEM>>> =
+    SyncUnsafeCell::new(None);
+
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) {
     info!("Core0: STM32H755 Embassy HSEM Test.");
 
+    unsafe {
+        for i in 0..10 {
+            shared::MAILBOX[i] = 0;
+        }
+    }
     // Wait for Core1 to be finished with its init
     // tasks and in Stop mode
     hal_ext::wait_for_core1();
@@ -68,29 +81,35 @@ async fn main(_spawner: Spawner) {
     let mut led_green = Output::new(p.PB0, Level::Low, Speed::Low);
     let mut led_red = Output::new(p.PB14, Level::Low, Speed::Low);
 
-    let mut hsem = HardwareSemaphore::new(p.HSEM, Irqs);
+    let hsem = HardwareSemaphore::new(p.HSEM, Irqs);
+
+    // initialize global HSEM instance
+    unsafe { *HSEM_INSTANCE.get() = Some(hsem) };
 
     unsafe { NVIC::unmask(embassy_stm32::pac::Interrupt::HSEM1) };
     // Take the semaphore for waking Core1 (CM4)
-    if let Err(_err) = hsem.one_step_lock(0) {
+    if !get_global_hsem().one_step_lock(0) {
         info!("Error taking semaphore 0");
     } else {
         info!("Semaphore 0 taken");
     }
 
+    let mut core_1_blink_delay = 500;
+    set_core1_blink_delay(core_1_blink_delay).await;
+
     // Wake Core1 (CM4)
-    hsem.unlock(0, 0);
+    get_global_hsem().unlock(0, 0);
     info!("Core1 (CM4) woken");
     led_green.set_high();
     Timer::after_millis(250).await;
     led_green.set_low();
 
     info!("Waiting for Sem 1");
-    let _ = hsem.wait_unlocked(1).await;
+    let _ = get_global_hsem().wait_unlocked(1).await;
     led_green.set_high();
     led_red.set_high();
     info!("Waiting for Sem 2");
-    let _ = hsem.wait_unlocked(2).await;
+    let _ = get_global_hsem().wait_unlocked(2).await;
     led_red.set_low();
     led_green.set_low();
 
@@ -102,5 +121,40 @@ async fn main(_spawner: Spawner) {
         led_red.set_high();
         Timer::after_millis(500).await;
         led_red.set_low();
+        info!("Set Core 1 blink delay {}", core_1_blink_delay);
+        set_core1_blink_delay(core_1_blink_delay).await;
+        if core_1_blink_delay < 100 {
+            core_1_blink_delay = 500;
+        }
+        core_1_blink_delay -= 50;
+    }
+}
+
+async fn set_core1_blink_delay(freq: u32) {
+    let mut retry = 10;
+    while !get_global_hsem().lock(5).await && retry > 0 {
+        Timer::after_micros(50).await;
+        retry -= 1;
+    }
+    if retry > 0 {
+        //let mut mailbox = *shared::MAILBOX.get() as [u32; 10];
+        unsafe {
+            shared::MAILBOX[0] = freq;
+        };
+
+        get_global_hsem().unlock(5, 0);
+    } else {
+        // Core1 has asquired the semaphore and is
+        // not releasing it - crashed?
+        defmt::panic!("Failed to asquire semaphore 1");
+    }
+}
+
+fn get_global_hsem() -> &'static mut HardwareSemaphore<'static, HSEM> {
+    unsafe {
+        match *HSEM_INSTANCE.get() {
+            Some(ref mut obj) => obj,
+            None => defmt::panic!("HardwareSemaphore was not initialized"),
+        }
     }
 }