stm32: Refactor DMA interrupts

Previously, every dma interrupt handler called the same `on_irq`
function which had to check the state of every dma channel.

Now, each dma interrupt handler only calls an `on_irq` method for its
corresponding channel or channels.

embassy-stm32/build.rs

@@ -105,46 +105,37 @@ fn main() {
     // ========
     // Generate DMA IRQs.
 
-    let mut dma_irqs: HashSet<&str> = HashSet::new();
+    let mut dma_irqs: HashMap<&str, Vec<(&str, &str)>> = HashMap::new();
-    let mut bdma_irqs: HashSet<&str> = HashSet::new();
 
     for p in METADATA.peripherals {
         if let Some(r) = &p.registers {
-            match r.kind {
+            if r.kind == "dma" || r.kind == "bdma" {
-                "dma" => {
+                for irq in p.interrupts {
-                    for irq in p.interrupts {
+                    dma_irqs
-                        dma_irqs.insert(irq.interrupt);
+                        .entry(irq.interrupt)
-                    }
+                        .or_default()
+                        .push((p.name, irq.signal));
                 }
-                "bdma" => {
-                    for irq in p.interrupts {
-                        bdma_irqs.insert(irq.interrupt);
-                    }
-                }
-                _ => {}
             }
         }
     }
 
-    let tokens: Vec<_> = dma_irqs.iter().map(|s| format_ident!("{}", s)).collect();
+    for (irq, channels) in dma_irqs {
-    g.extend(quote! {
+        let irq = format_ident!("{}", irq);
-        #(
-            #[crate::interrupt]
-            unsafe fn #tokens () {
-                crate::dma::dma::on_irq();
-            }
-        )*
-    });
 
-    let tokens: Vec<_> = bdma_irqs.iter().map(|s| format_ident!("{}", s)).collect();
+        let channels = channels
-    g.extend(quote! {
+            .iter()
-        #(
+            .map(|(dma, ch)| format_ident!("{}_{}", dma, ch));
+
+        g.extend(quote! {
             #[crate::interrupt]
-            unsafe fn #tokens () {
+            unsafe fn #irq () {
-                crate::dma::bdma::on_irq();
+                #(
+                    <crate::peripherals::#channels as crate::dma::sealed::Channel>::on_irq();
+                )*
             }
-        )*
+        });
-    });
+    }
 
     // ========
     // Generate RccPeripheral impls

embassy-stm32/src/dma/bdma.rs

@@ -38,26 +38,6 @@ impl State {
 
 static STATE: State = State::new();
 
-pub(crate) unsafe fn on_irq() {
-    foreach_peripheral! {
-        (bdma, BDMA1) => {
-            // BDMA1 in H7 doesn't use DMAMUX, which breaks
-        };
-        (bdma, $dma:ident) => {
-            let isr = pac::$dma.isr().read();
-            foreach_dma_channel! {
-                ($channel_peri:ident, $dma, bdma, $channel_num:expr, $index:expr, $dmamux:tt) => {
-                    let cr = pac::$dma.ch($channel_num).cr();
-                    if isr.tcif($channel_num) && cr.read().tcie() {
-                        cr.write(|_| ()); // Disable channel interrupts with the default value.
-                        STATE.ch_wakers[$index].wake();
-                    }
-                };
-            }
-        };
-    }
-}
-
 /// safety: must be called only once
 pub(crate) unsafe fn init() {
     foreach_interrupt! {
@@ -150,6 +130,12 @@ foreach_dma_channel! {
             fn set_waker(&mut self, waker: &Waker) {
                 unsafe { low_level_api::set_waker($index, waker) }
             }
+
+            fn on_irq() {
+                unsafe {
+                    low_level_api::on_irq_inner(pac::$dma_peri, $channel_num, $index);
+                }
+            }
         }
 
         impl crate::dma::Channel for crate::peripherals::$channel_peri {}
@@ -243,4 +229,18 @@ mod low_level_api {
             w.set_teif(channel_number as _, true);
         });
     }
+
+    /// Safety: Must be called with a matching set of parameters for a valid dma channel
+    pub unsafe fn on_irq_inner(dma: pac::bdma::Dma, channel_num: u8, index: u8) {
+        let channel_num = channel_num as usize;
+        let index = index as usize;
+
+        let isr = dma.isr().read();
+        let cr = dma.ch(channel_num).cr();
+
+        if isr.tcif(channel_num) && cr.read().tcie() {
+            cr.write(|_| ()); // Disable channel interrupts with the default value.
+            STATE.ch_wakers[index].wake();
+        }
+    }
 }

embassy-stm32/src/dma/dma.rs

@@ -36,22 +36,6 @@ impl State {
 
 static STATE: State = State::new();
 
-pub(crate) unsafe fn on_irq() {
-    foreach_peripheral! {
-        (dma, $dma:ident) => {
-            foreach_dma_channel! {
-                ($channel_peri:ident, $dma, dma, $channel_num:expr, $index:expr, $dmamux:tt) => {
-                    let cr = pac::$dma.st($channel_num).cr();
-                    if pac::$dma.isr($channel_num/4).read().tcif($channel_num%4) && cr.read().tcie() {
-                        cr.write(|_| ()); // Disable channel interrupts with the default value.
-                        STATE.ch_wakers[$index].wake();
-                    }
-                };
-            }
-        };
-    }
-}
-
 /// safety: must be called only once
 pub(crate) unsafe fn init() {
     foreach_interrupt! {
@@ -137,6 +121,12 @@ foreach_dma_channel! {
             fn set_waker(&mut self, waker: &Waker) {
                 unsafe {low_level_api::set_waker($index, waker )}
             }
+
+            fn on_irq() {
+                unsafe {
+                    low_level_api::on_irq_inner(pac::$dma_peri, $channel_num, $index);
+                }
+            }
         }
 
         impl crate::dma::Channel for crate::peripherals::$channel_peri { }
@@ -240,4 +230,18 @@ mod low_level_api {
             w.set_teif(isrbit, true);
         });
     }
+
+    /// Safety: Must be called with a matching set of parameters for a valid dma channel
+    pub unsafe fn on_irq_inner(dma: pac::dma::Dma, channel_num: u8, index: u8) {
+        let channel_num = channel_num as usize;
+        let index = index as usize;
+
+        let cr = dma.st(channel_num).cr();
+        let isr = dma.isr(channel_num / 4).read();
+
+        if isr.tcif(channel_num % 4) && cr.read().tcie() {
+            cr.write(|_| ()); // Disable channel interrupts with the default value.
+            STATE.ch_wakers[index].wake();
+        }
+    }
 }

embassy-stm32/src/dma/mod.rs

@@ -88,6 +88,11 @@ pub(crate) mod sealed {
 
         /// Sets the waker that is called when this channel stops (either completed or manually stopped)
         fn set_waker(&mut self, waker: &Waker);
+
+        /// This is called when this channel triggers an interrupt.
+        /// Note: Because some channels share an interrupt, this function might be
+        /// called for a channel that didn't trigger an interrupt.
+        fn on_irq();
     }
 }