Add Board Support for RPi3

nucleus/src/main.rs

@@ -29,6 +29,7 @@ extern crate rlibc; // To enable linking memory intrinsics.
 pub mod arch;
 pub use arch::*;
 mod macros;
+mod platform;
 #[cfg(feature = "qemu")]
 mod qemu;
 #[cfg(test)]

nucleus/src/platform/README.md

@@ -0,0 +1,3 @@
+# Board Support Packages
+
+This directory contains support for specific Boards like RaspberryPi3 etc.

nucleus/src/platform/mod.rs

@@ -0,0 +1,5 @@
+/*
+ * SPDX-License-Identifier: BlueOak-1.0.0
+ * Copyright (c) Berkus Decker <berkus+vesper@metta.systems>
+ */
+pub mod rpi3;

nucleus/src/platform/rpi3/mod.rs

@@ -0,0 +1,41 @@
+/*
+ * SPDX-License-Identifier: BlueOak-1.0.0
+ * Copyright (c) Berkus Decker <berkus+vesper@metta.systems>
+ */
+
+#![allow(dead_code)]
+
+/// See BCM2835-ARM-Peripherals.pdf
+/// See https://www.raspberrypi.org/forums/viewtopic.php?t=186090 for more details.
+
+pub struct BcmHost;
+
+impl BcmHost {
+    /// This returns the ARM-side physical address where peripherals are mapped.
+    ///
+    /// As per https://www.raspberrypi.org/documentation/hardware/raspberrypi/peripheral_addresses.md
+    /// BCM SOC could address only 1Gb of memory, so 0x4000_0000 is the high watermark.
+    pub const fn get_peripheral_address() -> usize {
+        0x3f00_0000
+    }
+
+    /// This returns the size of the peripherals' space.
+    pub const fn get_peripheral_size() -> usize {
+        0x0100_0000
+    }
+
+    /// This returns the bus address of the SDRAM.
+    pub const fn get_sdram_address() -> usize {
+        0xc000_0000 // uncached
+    }
+
+    /// As per https://www.raspberrypi.org/forums/viewtopic.php?p=1170522#p1170522
+    ///
+    pub fn bus2phys(bus: usize) -> usize {
+        bus & !0xc000_0000
+    }
+
+    pub fn phys2bus(phys: usize) -> usize {
+        phys | 0xc000_0000
+    }
+}