From cb8a10ca26153c1cdd63edf73fe8debb1bdd8899 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Wed, 2 Feb 2022 17:04:17 -0700
Subject: [PATCH] Implement disk read

---
 Cargo.lock  |  1 +
 Cargo.toml  |  3 ++-
 src/disk.rs | 51 +++++++++++++++++++++++++++++++++------------------
 src/lib.rs  |  1 +
 4 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 4825575c13..d00dd5209b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -98,6 +98,7 @@ name = "redox_bootloader"
 version = "0.1.0"
 dependencies = [
  "linked_list_allocator",
+ "redox_syscall",
  "redoxfs",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 122fc2b258..080c29bfdd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,8 @@ crate-type = ["staticlib"]
 
 
 [dependencies]
-linked_list_allocator = "0.9.0"
+linked_list_allocator = "0.9.1"
+redox_syscall = "0.2.10"
 
 [dependencies.redoxfs]
 git = "https://gitlab.redox-os.org/redox-os/redoxfs.git"
diff --git a/src/disk.rs b/src/disk.rs
index faaf0422f3..937ef187b4 100644
--- a/src/disk.rs
+++ b/src/disk.rs
@@ -1,10 +1,8 @@
-use std::fs::{File, OpenOptions};
-use std::io::{Read, Seek, SeekFrom, Write};
-use std::path::Path;
+use core::{mem, ptr};
+use redoxfs::{BLOCK_SIZE, Disk};
 use syscall::error::{Error, Result, EIO};
 
-use crate::disk::Disk;
-use crate::BLOCK_SIZE;
+use crate::{DISK_ADDRESS_PACKET_ADDR, DISK_BIOS_ADDR, ThunkData};
 
 #[derive(Clone, Copy)]
 #[repr(packed)]
@@ -21,10 +19,10 @@ impl DiskAddressPacket {
     pub fn from_block(block: u64) -> DiskAddressPacket {
         let blocks = BLOCK_SIZE / 512;
         DiskAddressPacket {
-            size: mem::size_of::<DiskAddressPacket>(),
+            size: mem::size_of::<DiskAddressPacket>() as u8,
             reserved: 0,
-            blocks,
-            buffer: DISK_BIOS_ADDR,
+            blocks: blocks as u16,
+            buffer: DISK_BIOS_ADDR as u16,
             segment: 0,
             address: block * blocks,
         }
@@ -36,27 +34,44 @@ pub struct DiskBios {
 }
 
 impl DiskBios {
-    pub fn block_dap(block: u64) -> DiskAddressPacket {
+    pub fn new(thunk13: extern "C" fn()) -> Self {
+        Self { thunk13 }
     }
 }
 
 impl Disk for DiskBios {
     unsafe fn read_at(&mut self, block: u64, buffer: &mut [u8]) -> Result<usize> {
-        let mut dap = DiskAddressPacket::from_block(block);
+        for (i, chunk) in buffer.chunks_mut(BLOCK_SIZE as usize).enumerate() {
+            let mut dap = DiskAddressPacket::from_block(block);
+            ptr::write(DISK_ADDRESS_PACKET_ADDR as *mut DiskAddressPacket, dap);
 
-        try_disk!(self.file.seek(SeekFrom::Start(block * BLOCK_SIZE)));
-        let count = try_disk!(self.file.read(buffer));
-        Ok(count)
+            let mut data = ThunkData::new();
+            data.ax = 0x4200;
+            //TODO: get original drive number!
+            data.dx = 0x0080;
+            data.si = DISK_ADDRESS_PACKET_ADDR as u16;
+
+            data.with(self.thunk13);
+
+            //TODO: return result on error
+            assert_eq!(data.ax, 0);
+
+            //TODO: check blocks transferred
+            dap = ptr::read(DISK_ADDRESS_PACKET_ADDR as *mut DiskAddressPacket);
+
+            ptr::copy(DISK_BIOS_ADDR as *const u8, chunk.as_mut_ptr(), chunk.len());
+        }
+
+        Ok(buffer.len())
     }
 
     unsafe fn write_at(&mut self, block: u64, buffer: &[u8]) -> Result<usize> {
-        try_disk!(self.file.seek(SeekFrom::Start(block * BLOCK_SIZE)));
-        let count = try_disk!(self.file.write(buffer));
-        Ok(count)
+        //TODO
+        Ok(0)
     }
 
     fn size(&mut self) -> Result<u64> {
-        let size = try_disk!(self.file.seek(SeekFrom::End(0)));
-        Ok(size)
+        //TODO
+        Ok(0)
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index c368ddfbe8..88150dcdde 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -19,6 +19,7 @@ use self::thunk::ThunkData;
 use self::vbe::{VbeCardInfo, VbeModeInfo};
 use self::vga::{VgaTextBlock, VgaTextColor, Vga};
 
+mod disk;
 mod panic;
 mod thunk;
 mod vbe;