dma: use const initializer for manager

src/runtime/src/kernel/core1.rs

@@ -15,7 +15,6 @@ use crate::eh_artiq;
 use super::{
     api::resolve,
     rpc::rpc_send_async,
-    dma::init_dma,
     CHANNEL_0TO1, CHANNEL_1TO0,
     KERNEL_CHANNEL_0TO1, KERNEL_CHANNEL_1TO0,
     KERNEL_IMAGE,
@@ -126,9 +125,6 @@ pub fn main_core1() {
     enable_fpu();
     debug!("FPU enabled on Core1");
 
-    init_dma();
-    debug!("Init DMA!");
-
     let mut core1_tx = None;
     while core1_tx.is_none() {
         core1_tx = CHANNEL_1TO0.lock().take();

src/runtime/src/kernel/dma.rs

@@ -46,7 +46,7 @@ pub struct Manager {
 // Copied from https://github.com/m-labs/artiq/blob/master/artiq/firmware/runtime/rtio_dma.rs
 // basically without modification except removing some warnings.
 impl Manager {
-    pub fn new() -> Manager {
+    pub const fn new() -> Manager {
         Manager {
             entries: BTreeMap::new(),
             recording_name: String::new(),
@@ -106,7 +106,7 @@ impl Manager {
 }
 
 
-static mut DMA_MANAGER: Option<Manager> = None;
+static mut DMA_MANAGER: Manager = Manager::new();
 
 #[repr(C)]
 pub struct DmaTrace {
@@ -114,16 +114,9 @@ pub struct DmaTrace {
     address:  i32,
 }
 
-pub fn init_dma() {
-    unsafe {
-        DMA_MANAGER = Some(Manager::new());
-    }
-}
-
 fn dma_record_flush() {
     unsafe {
-        let manager = DMA_MANAGER.as_mut().unwrap();
-        manager.record_append(&DMA_RECORDER.buffer[..DMA_RECORDER.data_len]);
+        DMA_MANAGER.record_append(&DMA_RECORDER.buffer[..DMA_RECORDER.data_len]);
         DMA_RECORDER.data_len = 0;
     }
 }
@@ -143,8 +136,7 @@ pub extern fn dma_record_start(name: CSlice<u8>) {
                        dma_record_output_wide as *const ()).unwrap();
 
         DMA_RECORDER.active = true;
-        let manager = DMA_MANAGER.as_mut().unwrap();
-        manager.record_start(name);
+        DMA_MANAGER.record_start(name);
     }
 }
 
@@ -163,8 +155,7 @@ pub extern fn dma_record_stop(duration: i64) {
                        rtio::output_wide as *const ()).unwrap();
 
         DMA_RECORDER.active = false;
-        let manager = DMA_MANAGER.as_mut().unwrap();
-        manager.record_stop(duration as u64);
+        DMA_MANAGER.record_stop(duration as u64);
     }
 }
 
@@ -238,23 +229,21 @@ pub extern fn dma_record_output_wide(target: i32, words: CSlice<i32>) {
 pub extern fn dma_erase(name: CSlice<u8>) {
     let name = str::from_utf8(name.as_ref()).unwrap();
 
-    let manager = unsafe {
-        DMA_MANAGER.as_mut().unwrap()
+    unsafe {
+        DMA_MANAGER.erase(name);
     };
-    manager.erase(name);
 }
 
 pub extern fn dma_retrieve(name: CSlice<u8>) -> DmaTrace {
     let name = str::from_utf8(name.as_ref()).unwrap();
 
-    let manager = unsafe {
-        DMA_MANAGER.as_mut().unwrap()
-    };
-    let (trace, duration) = manager.with_trace(name, |trace, duration| (trace.map(|v| {
+    let (trace, duration) = unsafe {
+        DMA_MANAGER.with_trace(name, |trace, duration| (trace.map(|v| {
             dcci_slice(v);
             dsb();
             v.as_ptr()
-    }), duration));
+        }), duration))
+    };
     match trace {
         Some(ptr) => Ok(DmaTrace {
             address: ptr as i32,

src/runtime/src/main.rs

@@ -4,6 +4,7 @@
 #![feature(alloc_error_handler)]
 #![feature(panic_info_message)]
 #![feature(c_variadic)]
+#![feature(const_btree_new)]
 
 extern crate alloc;