From 3fe13f96a191df4ee6a3f746b8bdd080744526d7 Mon Sep 17 00:00:00 2001
From: Tilman Sauerbeck <tilman@code-monkey.de>
Date: Sun, 16 Jun 2019 21:10:48 +0200
Subject: [PATCH] common: Add the nvic module.

Allows enabling and disabling of interrupts as well as configuring
their priority.
---
 SConscript.libcommon |  1 +
 src/common/lib.rs    |  1 +
 src/common/nvic.rs   | 64 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 66 insertions(+)
 create mode 100644 src/common/nvic.rs

diff --git a/SConscript.libcommon b/SConscript.libcommon
index 7482ee3..a23c79b 100644
--- a/SConscript.libcommon
+++ b/SConscript.libcommon
@@ -4,6 +4,7 @@ env = env.Clone()
 source_files_rs = [
     'src/common/lib.rs', # Must be listed first (see below).
     'src/common/register.rs',
+    'src/common/nvic.rs',
 ]
 
 source_files_c = [
diff --git a/src/common/lib.rs b/src/common/lib.rs
index f2feb14..0fa0f6b 100644
--- a/src/common/lib.rs
+++ b/src/common/lib.rs
@@ -27,6 +27,7 @@
 #![feature(lang_items)]
 
 pub mod register;
+pub mod nvic;
 
 #[lang="eh_personality"]
 extern fn eh_personality() {
diff --git a/src/common/nvic.rs b/src/common/nvic.rs
new file mode 100644
index 0000000..38aece3
--- /dev/null
+++ b/src/common/nvic.rs
@@ -0,0 +1,64 @@
+/*
+ * 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 register;
+
+type Reg32 = register::Register<u32>;
+
+const NVIC_BASE: u32 = 0xe000e100;
+
+const NVIC_ISER: u32 = NVIC_BASE + 0x000;
+const NVIC_ICER: u32 = NVIC_BASE + 0x080;
+const NVIC_IP  : u32 = NVIC_BASE + 0x300;
+
+pub fn enable_irq(irq_number: u32) {
+    let mut iser = Reg32::new(NVIC_ISER);
+
+    iser.write(1 << irq_number);
+}
+
+pub fn disable_irq(irq_number: u32) {
+    let mut icer = Reg32::new(NVIC_ICER);
+
+    icer.write(1 << irq_number);
+}
+
+fn ip_offset(irq_number: u32) -> u32 {
+    irq_number & !3
+}
+
+fn ip_shift(irq_number: u32) -> u32 {
+    (irq_number & 3) * 8
+}
+
+pub fn set_priority(irq_number: u32, priority: u32) {
+    let mut ip = Reg32::new(NVIC_IP + ip_offset(irq_number));
+
+    ip.modify(|v| {
+        let mut m = v;
+
+        m &= !(0xff << ip_shift(irq_number));
+        m |= priority << ip_shift(irq_number);
+        m
+    });
+}
-- 
2.30.2