WIP: ACPI

Map and find ACPI tables, starting with RSDT

arch/x86_64/src/acpi/mod.rs

@@ -0,0 +1,74 @@
+//! # ACPI
+//! Code to parse the ACPI tables
+
+use core::mem;
+
+use memory::{Frame, FrameAllocator};
+use paging::{entry, ActivePageTable, Page, PhysicalAddress, VirtualAddress};
+
+use self::sdt::SDTHeader;
+
+pub mod sdt;
+
+/// Parse the ACPI tables to gather CPU, interrupt, and timer information
+pub unsafe fn init<A>(allocator: &mut A, active_table: &mut ActivePageTable) -> Option<Acpi>
+    where A: FrameAllocator
+{
+    let start_addr = 0xE0000;
+    let end_addr = 0xFFFFF;
+
+    // Map all of the ACPI table space
+    {
+        let start_frame = Frame::containing_address(PhysicalAddress::new(start_addr));
+        let end_frame = Frame::containing_address(PhysicalAddress::new(end_addr));
+        for frame in Frame::range_inclusive(start_frame, end_frame) {
+            active_table.identity_map(frame, entry::PRESENT | entry::NO_EXECUTE, allocator);
+        }
+    }
+
+    // Search for RSDP
+    if let Some(rsdp) = RSDP::search(start_addr, end_addr) {
+        println!("{:?}", rsdp);
+
+        let rsdt_frame = Frame::containing_address(PhysicalAddress::new(rsdp.rsdt_address as usize));
+        active_table.identity_map(rsdt_frame, entry::PRESENT | entry::NO_EXECUTE, allocator);
+
+        let sdt = unsafe { &*(rsdp.rsdt_address as usize as *const SDTHeader) };
+        
+        for &c in sdt.signature.iter() {
+            print!("{}", c as char);
+        }
+        println!(" {:?}", sdt);
+    }
+
+    None
+}
+
+pub struct Acpi;
+
+/// RSDP
+#[derive(Copy, Clone, Debug)]
+#[repr(packed)]
+pub struct RSDP {
+    signature: [u8; 8],
+    checksum: u8,
+    oemid: [u8; 6],
+    revision: u8,
+    rsdt_address: u32,
+    length: u32,
+    xsdt_address: u32,
+    extended_checksum: u8,
+    reserved: [u8; 3]
+}
+
+impl RSDP {
+    pub fn search(start_addr: usize, end_addr: usize) -> Option<RSDP> {
+        for i in 0 .. (end_addr + 1 - start_addr)/mem::size_of::<RSDP>() {
+            let mut rsdp = unsafe { &*(start_addr as *const RSDP).offset(i as isize) };
+            if &rsdp.signature == b"RSD PTR " {
+                return Some(*rsdp);
+            }
+        }
+        None
+    }
+}

arch/x86_64/src/acpi/sdt.rs

@@ -0,0 +1,13 @@
+#[derive(Copy, Clone, Debug)]
+#[repr(packed)]
+pub struct SDTHeader {
+  pub signature: [u8; 4],
+  pub length: u32,
+  pub revision: u8,
+  pub checksum: u8,
+  pub oem_id: [u8; 6],
+  pub oem_table_id: [u8; 8],
+  pub oem_revision: u32,
+  pub creator_id: u32,
+  pub creator_revision: u32,
+}