From d89a89f1bd29537732c7a718ce5d8760b60a8238 Mon Sep 17 00:00:00 2001
From: Tilman Sauerbeck <tilman@code-monkey.de>
Date: Sun, 16 Jun 2019 21:05:58 +0200
Subject: [PATCH] common: Add the register module.

Allows 8, 16 or 32 bit access to peripheral registers.
---
 SConscript.libcommon   |  1 +
 src/common/lib.rs      |  2 ++
 src/common/register.rs | 60 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+)
 create mode 100644 src/common/register.rs

diff --git a/SConscript.libcommon b/SConscript.libcommon
index 902af89..7482ee3 100644
--- a/SConscript.libcommon
+++ b/SConscript.libcommon
@@ -3,6 +3,7 @@ env = env.Clone()
 
 source_files_rs = [
     'src/common/lib.rs', # Must be listed first (see below).
+    'src/common/register.rs',
 ]
 
 source_files_c = [
diff --git a/src/common/lib.rs b/src/common/lib.rs
index 3ed90e8..f2feb14 100644
--- a/src/common/lib.rs
+++ b/src/common/lib.rs
@@ -26,6 +26,8 @@
 #![crate_type="rlib"]
 #![feature(lang_items)]
 
+pub mod register;
+
 #[lang="eh_personality"]
 extern fn eh_personality() {
 }
diff --git a/src/common/register.rs b/src/common/register.rs
new file mode 100644
index 0000000..9a3f3c3
--- /dev/null
+++ b/src/common/register.rs
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2019 Tilman Sauerbeck (tilman at code-monkey de)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+use core::ptr;
+use core::marker::PhantomData;
+
+pub struct Register<T>
+{
+    pub address: u32,
+    phantom: PhantomData<T>,
+}
+
+impl<T> Register<T> {
+    pub fn new(addr: u32) -> Register<T> {
+        Register {
+            address: addr,
+            phantom: PhantomData,
+        }
+    }
+
+    pub fn read(&self) -> T {
+        let ptr = self.address as *const T;
+
+        unsafe { ptr::read_volatile(ptr) }
+    }
+
+    pub fn write(&mut self, value: T) {
+        let ptr = self.address as *mut T;
+
+        unsafe { ptr::write_volatile(ptr, value) }
+    }
+
+    pub fn modify<F>(&mut self, func: F)
+        where F: FnOnce(T) -> T
+    {
+        let mut v = self.read();
+        v = func(v);
+        self.write(v);
+    }
+}
-- 
2.30.2