RTIO DMA: Compiled but not working.

* Cache flush should be done before playback instead when getting the
  handler.
* `csr::rtio_dma::enable_read()` would loop forever, probably bug in the
  gateware.

src/libdyld/Cargo.toml

@@ -8,3 +8,5 @@ name = "dyld"
 
 [dependencies]
 log = "0.4"
+libcortex_a9 = { git = "https://git.m-labs.hk/M-Labs/zc706.git" }
+

src/libdyld/src/lib.rs

@@ -2,6 +2,7 @@
 
 extern crate alloc;
 extern crate log;
+extern crate libcortex_a9;
 
 use core::{convert, fmt, str};
 use alloc::string::String;

src/libdyld/src/reloc.rs

@@ -7,6 +7,10 @@ use super::{
     image::Image,
     Library,
 };
+use libcortex_a9::{
+    cache::{dcci_slice, iciallu, bpiall},
+    asm::{dsb, isb},
+};
 
 pub trait Relocatable {
     fn offset(&self) -> usize;
@@ -154,6 +158,13 @@ pub fn rebind(
             _ => {}
         }
     }
+    // FIXME: the cache maintainance operations may be more than enough,
+    // may cause performance degradation.
+    dcci_slice(lib.image.data);
+    iciallu();
+    bpiall();
+    dsb();
+    isb();
 
     Ok(())
 }