Add DMAMUX support

examples/uart-dma.rs

@@ -0,0 +1,53 @@
+#![no_main]
+#![no_std]
+
+extern crate cortex_m_rt as rt;
+extern crate panic_halt;
+extern crate stm32g0xx_hal as hal;
+
+use core::fmt::Write;
+
+use hal::prelude::*;
+use hal::serial::*;
+use hal::stm32;
+use hal::dma::{self, Channel, Target};
+
+use rt::entry;
+
+#[entry]
+fn main() -> ! {
+    let dp = stm32::Peripherals::take().expect("cannot take peripherals");
+    let mut rcc = dp.RCC.constrain();
+    let gpioa = dp.GPIOA.split(&mut rcc);
+
+    let mut usart1 = dp.USART1.usart(
+        gpioa.pa9,
+        gpioa.pa10,
+        FullConfig::default().baudrate(115200.bps()), &mut rcc).unwrap();
+
+    writeln!(usart1, "Hello without DMA\r\n").unwrap();
+
+    let tx_buffer: [u8; 16] = *b"Hello with DMA!\n";
+
+    let (mut tx, _rx) = usart1.split();
+
+    let mut dma = dp.DMA.split(&mut rcc, dp.DMAMUX);
+
+    let usart = unsafe { &(*stm32::USART1::ptr()) };
+    let tx_data_register_addr = &usart.tdr as *const _ as u32;
+    let tx_dma_buf_addr : u32 = tx_buffer.as_ptr() as u32;
+
+    dma.ch1.set_direction(dma::Direction::FromMemory);
+    dma.ch1.set_memory_address(tx_dma_buf_addr, true);
+    dma.ch1.set_peripheral_address(tx_data_register_addr, false);
+    dma.ch1.set_transfer_length(tx_buffer.len() as u16);
+
+    dma.ch1.select_peripheral(tx.dmamux());
+
+    tx.enable_dma();
+    dma.ch1.enable();
+
+    loop {
+        continue;
+    }
+}