rp: add initial version

embassy-rp/src/dma.rs

@@ -0,0 +1,87 @@
+use core::sync::atomic::{compiler_fence, Ordering};
+
+use defmt::{assert, *};
+
+use crate::{pac, peripherals};
+use pac::dma::vals;
+
+pub struct Dma<T: Channel> {
+    inner: T,
+}
+
+impl<T: Channel> Dma<T> {
+    pub fn copy(inner: T, from: &[u32], to: &mut [u32]) {
+        assert!(from.len() == to.len());
+
+        unsafe {
+            let p = inner.regs();
+
+            p.read_addr().write_value(from.as_ptr() as u32);
+            p.write_addr().write_value(to.as_mut_ptr() as u32);
+            p.trans_count().write_value(from.len() as u32);
+
+            compiler_fence(Ordering::SeqCst);
+
+            p.ctrl_trig().write(|w| {
+                w.set_data_size(vals::DataSize::SIZE_WORD);
+                w.set_incr_read(true);
+                w.set_incr_write(true);
+                w.set_chain_to(inner.number());
+                w.set_en(true);
+            });
+
+            while p.ctrl_trig().read().busy() {}
+
+            compiler_fence(Ordering::SeqCst);
+        }
+    }
+}
+
+mod sealed {
+    use super::*;
+
+    pub trait Channel {
+        fn number(&self) -> u8;
+
+        fn regs(&self) -> pac::dma::Channel {
+            pac::DMA.ch(self.number() as _)
+        }
+    }
+}
+
+pub trait Channel: sealed::Channel {}
+
+pub struct AnyChannel {
+    number: u8,
+}
+
+impl Channel for AnyChannel {}
+impl sealed::Channel for AnyChannel {
+    fn number(&self) -> u8 {
+        self.number
+    }
+}
+
+macro_rules! channel {
+    ($type:ident, $num:expr) => {
+        impl Channel for peripherals::$type {}
+        impl sealed::Channel for peripherals::$type {
+            fn number(&self) -> u8 {
+                $num
+            }
+        }
+    };
+}
+
+channel!(DMA_CH0, 0);
+channel!(DMA_CH1, 1);
+channel!(DMA_CH2, 2);
+channel!(DMA_CH3, 3);
+channel!(DMA_CH4, 4);
+channel!(DMA_CH5, 5);
+channel!(DMA_CH6, 6);
+channel!(DMA_CH7, 7);
+channel!(DMA_CH8, 8);
+channel!(DMA_CH9, 9);
+channel!(DMA_CH10, 10);
+channel!(DMA_CH11, 11);