proto fw: add rx downconn debug in

src/libboard_artiq/src/cxp_proto.rs

@@ -191,3 +191,48 @@ pub fn print_packet(pak: &[u8]) {
     println!("]");
     println!("============================================");
 }
+
+pub fn downconn_debug_main() {
+    downconn_debug_send(&Packet::CtrlRead {
+        addr: 0x00,
+        length: 0x04,
+    });
+
+    const LEN: usize = 100;
+    let mut pak_arr: [u32; LEN] = [0; LEN];
+    let mut i: usize = 0;
+    unsafe {
+        while csr::cxp::downconn_debug_out_dout_valid_read() == 1 {
+            pak_arr[i] = csr::cxp::downconn_debug_out_dout_pak_read();
+            // println!("received {:#04X}", pak_arr[i]);
+            csr::cxp::downconn_debug_out_inc_write(1);
+            i += 1;
+            if i == LEN {
+                break;
+            }
+        }
+    }
+
+    // TODO: turn the u32 slice back to u8
+
+    println!("{:#010X?}", pak_arr)
+}
+
+pub fn downconn_debug_send(packet: &Packet) -> Result<(), Error> {
+    let mut buffer: [u8; MAX_PACKET] = [0; MAX_PACKET];
+    let mut writer = Cursor::new(&mut buffer[..]);
+
+    packet.write_to(&mut writer)?;
+
+    unsafe {
+        let len = writer.position();
+        csr::cxp::downconn_debug_src_len_write(len as u8);
+        for data in writer.get_ref()[..len].iter() {
+            while csr::cxp::downconn_debug_src_writeable_read() == 0 {}
+            csr::cxp::upconn_command_data_write(*data);
+            csr::cxp::downconn_debug_src_data_write(*data);
+        }
+    }
+
+    Ok(())
+}