From 3cb666d26e4e433c9aff1533a9a04f8430170439 Mon Sep 17 00:00:00 2001
From: TheOddGarlic <umutinanerdogan@pm.me>
Date: Tue, 9 Aug 2022 11:11:15 +0300
Subject: [PATCH] allocate 16 frames for DMA

---
 ableos/src/arch/x86_64/memory.rs |  8 ++++-
 ableos/src/devices/pci/piix.rs   | 59 +++++++++++++++++++++++++++++---
 ableos/src/kmain.rs              |  5 +--
 3 files changed, 65 insertions(+), 7 deletions(-)

diff --git a/ableos/src/arch/x86_64/memory.rs b/ableos/src/arch/x86_64/memory.rs
index 338daae0..35e4fbe2 100644
--- a/ableos/src/arch/x86_64/memory.rs
+++ b/ableos/src/arch/x86_64/memory.rs
@@ -1,7 +1,7 @@
 use bootloader::bootinfo::{MemoryMap, MemoryRegionType};
 use x86_64::{
     structures::paging::{
-        FrameAllocator, Mapper, OffsetPageTable, Page, PageTable, PhysFrame, Size4KiB,
+        FrameAllocator, Mapper, OffsetPageTable, Page, PageTable, PhysFrame, Size4KiB, FrameDeallocator,
     },
     PhysAddr, VirtAddr,
 };
@@ -109,3 +109,9 @@ unsafe impl FrameAllocator<Size4KiB> for BootInfoFrameAllocator {
         frame
     }
 }
+
+impl FrameDeallocator<Size4KiB> for BootInfoFrameAllocator {
+    unsafe fn deallocate_frame(&mut self, _frame: PhysFrame<Size4KiB>) {
+        // TODO
+    }
+}
diff --git a/ableos/src/devices/pci/piix.rs b/ableos/src/devices/pci/piix.rs
index 416aa329..5793530d 100644
--- a/ableos/src/devices/pci/piix.rs
+++ b/ableos/src/devices/pci/piix.rs
@@ -1,14 +1,19 @@
+use x86_64::structures::paging::{FrameAllocator, FrameDeallocator};
 // FIXME: platform agnostic paging stuff
-use x86_64::structures::paging::{PhysFrame, FrameAllocator, Size4KiB, mapper::MapToError, Mapper, Page};
+use x86_64::structures::paging::{PhysFrame, Size4KiB, mapper::MapToError, Mapper, Page};
 use x86_64::VirtAddr;
 
+use crate::arch::memory::BootInfoFrameAllocator;
+
 use super::{PciDeviceInfo, check_device};
 
 const PRDT_START: u64 = 0x_ffff_ffff_0000_0000;
+const BUFFER_START: u64 = 0x_ffff_ffff_0000_1000;
 
 pub struct Piix {
     device_info: PciDeviceInfo,
     prdt_frame: Option<PhysFrame>,
+    buffer_frames: Option<Vec<PhysFrame>>,
 }
 
 impl Piix {
@@ -19,18 +24,41 @@ impl Piix {
         Some(Self {
             device_info,
             prdt_frame: None,
+            buffer_frames: None,
         })
     }
 
     pub fn allocate_dma_frame(
         &mut self,
         mapper: &mut impl Mapper<Size4KiB>,
-        frame_allocator: &mut impl FrameAllocator<Size4KiB>,
+        frame_allocator: &mut BootInfoFrameAllocator,
     ) -> Result<(), MapToError<Size4KiB>> {
         use x86_64::structures::paging::PageTableFlags as Flags;
 
         let prdt_frame = frame_allocator.allocate_frame()
             .ok_or(MapToError::FrameAllocationFailed)?;
+        let buffer_frames = {
+            let mut frame = frame_allocator.allocate_frame()
+                .ok_or(MapToError::FrameAllocationFailed)?;
+            while !frame.start_address().is_aligned(0x10000u64) {
+                unsafe {
+                    frame_allocator.deallocate_frame(frame);
+                }
+
+                frame = frame_allocator.allocate_frame()
+                    .ok_or(MapToError::FrameAllocationFailed)?;
+            }
+
+            let mut frames = Vec::with_capacity(16);
+            frames.push(frame);
+            for _ in 0..15 {
+                let frame = frame_allocator.allocate_frame()
+                    .ok_or(MapToError::FrameAllocationFailed)?;;
+                frames.push(frame);
+            }
+
+            frames
+        };
         let flags = Flags::NO_CACHE | Flags::PRESENT | Flags::WRITABLE;
 
         unsafe {
@@ -39,11 +67,22 @@ impl Piix {
                 prdt_frame,
                 flags,
                 frame_allocator,
-            )?.flush()
+            )?.flush();
+
+            for (i, frame) in buffer_frames.iter().enumerate() {
+                mapper.map_to(
+                    Page::containing_address(VirtAddr::new(BUFFER_START + i as u64 * 0x1000)),
+                    *frame,
+                    flags,
+                    frame_allocator,
+                )?.flush()
+            }
         }
 
-        trace!("{prdt_frame:#?}");
+        trace!("prdt_frame: {prdt_frame:?}");
+        trace!("buffer_frames: {buffer_frames:?}");
         self.prdt_frame = Some(prdt_frame);
+        self.buffer_frames = Some(buffer_frames);
         Ok(())
     }
 
@@ -78,3 +117,15 @@ struct BusMasterInterface {
     /// Bus Master IDE Descriptor Table Pointer (secondary)
     pub bmidtps: u32,
 }
+
+#[repr(C, packed)]
+struct PhysRegionDescriptor {
+    /// Pointer to the data buffer
+    pub data_buffer: u32,
+    /// Byte count, 64K maximum per PRD transfer
+    pub byte_count: u16,
+    /// Reserved byte
+    pub _0: u8,
+    /// MSB marks end of transfer
+    pub eot: u8,
+}
diff --git a/ableos/src/kmain.rs b/ableos/src/kmain.rs
index eea56b20..ef24c9c9 100644
--- a/ableos/src/kmain.rs
+++ b/ableos/src/kmain.rs
@@ -8,6 +8,7 @@
 
 use core::sync::atomic::AtomicU64;
 
+use crate::arch::memory::BootInfoFrameAllocator;
 use crate::arch::{drivers::sysinfo::master, init, sloop};
 use crate::devices::pci::piix::Piix;
 use crate::relib::network::socket::{SimpleSock, Socket};
@@ -19,7 +20,7 @@ use kernel::KERNEL_VERSION;
 use spin::Lazy;
 
 // FIXME: platform agnostic paging stuff
-use x86_64::structures::paging::{Mapper, FrameAllocator, Size4KiB};
+use x86_64::structures::paging::{Mapper, Size4KiB};
 
 // TODO: Change this structure to allow for multiple cores loaded
 pub static KERNEL_CONF: Lazy<KernelConfig> = Lazy::new(KernelConfig::new);
@@ -27,7 +28,7 @@ pub static KERNEL_CONF: Lazy<KernelConfig> = Lazy::new(KernelConfig::new);
 /// The main entry point of the kernel
 pub fn kernel_main(
     mut mapper: impl Mapper<Size4KiB>,
-    mut frame_allocator: impl FrameAllocator<Size4KiB>,
+    mut frame_allocator: BootInfoFrameAllocator,
 ) -> ! {
     init::init();