allocate DMA frame

ableos/src/arch/x86_64/mod.rs

@@ -34,7 +34,7 @@ pub fn start(boot_info: &'static BootInfo) -> ! {
 
     allocator::init_heap(&mut mapper, &mut frame_allocator).expect("heap initialization failed");
 
-    crate::kmain::kernel_main();
+    crate::kmain::kernel_main(mapper, frame_allocator);
 }
 
 #[allow(unused)]

ableos/src/devices/pci/mod.rs

@@ -19,6 +19,9 @@ pub use enums::*;
 pub mod port;
 use port::*;
 
+// MassStorage_IDE (0x0101)
+pub mod piix;
+
 use self::devices::DeviceID;
 
 // PciDeviceInfo ///////////////////////////////////////////////////////////////

ableos/src/devices/pci/piix.rs

@@ -0,0 +1,80 @@
+// FIXME: platform agnostic paging stuff
+use x86_64::structures::paging::{PhysFrame, FrameAllocator, Size4KiB, mapper::MapToError, Mapper, Page};
+use x86_64::VirtAddr;
+
+use super::{PciDeviceInfo, check_device};
+
+const PRDT_START: u64 = 0x_ffff_ffff_0000_0000;
+
+pub struct Piix {
+    device_info: PciDeviceInfo,
+    prdt_frame: Option<PhysFrame>,
+}
+
+impl Piix {
+    pub fn new(bus: u8, device: u8) -> Option<Self> {
+        let device_info = check_device(bus, device)?;
+        trace!("device_info: {device_info}");
+
+        Some(Self {
+            device_info,
+            prdt_frame: None,
+        })
+    }
+
+    pub fn allocate_dma_frame(
+        &mut self,
+        mapper: &mut impl Mapper<Size4KiB>,
+        frame_allocator: &mut impl FrameAllocator<Size4KiB>,
+    ) -> Result<(), MapToError<Size4KiB>> {
+        use x86_64::structures::paging::PageTableFlags as Flags;
+
+        let prdt_frame = frame_allocator.allocate_frame()
+            .ok_or(MapToError::FrameAllocationFailed)?;
+        let flags = Flags::NO_CACHE | Flags::PRESENT | Flags::WRITABLE;
+
+        unsafe {
+            mapper.map_to(
+                Page::containing_address(VirtAddr::new(PRDT_START)),
+                prdt_frame,
+                flags,
+                frame_allocator,
+            )?.flush()
+        }
+
+        trace!("{prdt_frame:#?}");
+        self.prdt_frame = Some(prdt_frame);
+        Ok(())
+    }
+
+    pub fn read(&self) {
+        // bus master interface base address
+        let bmiba = self.device_info.bars[4] as *mut BusMasterInterface; 
+        // bmiba.bmidtpp = prdt;
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+#[repr(C, packed)]
+struct BusMasterInterface {
+    /// Bus Master IDE Command (primary)
+    pub bmicp: u8,
+    /// Reserved
+    pub _0: u8,
+    /// Bus Master IDE Status (primary)
+    pub bmisp: u8,
+    /// Reserved
+    pub _1: u8,
+    /// Bus Master IDE Descriptor Table Pointer (primary)
+    pub bmidtpp: u32,
+    /// Bus Master IDE Command (secondary)
+    pub bmics: u8,
+    /// Reserved
+    pub _2: u8,
+    /// Bus Master IDE Status (secondary)
+    pub bmiss: u8,
+    /// Reserved
+    pub _3: u8,
+    /// Bus Master IDE Descriptor Table Pointer (secondary)
+    pub bmidtps: u32,
+}

ableos/src/kmain.rs

@@ -9,6 +9,7 @@
 use core::sync::atomic::AtomicU64;
 
 use crate::arch::{drivers::sysinfo::master, init, sloop};
+use crate::devices::pci::piix::Piix;
 use crate::relib::network::socket::{SimpleSock, Socket};
 use crate::{
     boot_conf::KernelConfig, scratchpad, systeminfo::RELEASE_TYPE, TERM,
@@ -17,12 +18,17 @@ use crate::{filesystem, hardware};
 use kernel::KERNEL_VERSION;
 use spin::Lazy;
 
+// FIXME: platform agnostic paging stuff
+use x86_64::structures::paging::{Mapper, FrameAllocator, Size4KiB};
+
 // TODO: Change this structure to allow for multiple cores loaded
 pub static KERNEL_CONF: Lazy<KernelConfig> = Lazy::new(KernelConfig::new);
 
 /// The main entry point of the kernel
-#[no_mangle]
+pub fn kernel_main(
-pub fn kernel_main() -> ! {
+    mut mapper: impl Mapper<Size4KiB>,
+    mut frame_allocator: impl FrameAllocator<Size4KiB>,
+) -> ! {
     init::init();
 
     // /*
@@ -45,6 +51,10 @@ pub fn kernel_main() -> ! {
 
     filesystem::init().unwrap();
 
+    // FIXME: unhardcode this and do device discovery
+    let mut piix = Piix::new(0, 3).unwrap();
+    piix.allocate_dma_frame(&mut mapper, &mut frame_allocator).unwrap();
+
     /*
 
     // println!("abc");