atapi: Implement read support

ahcid/src/ahci/disk_ata.rs

@@ -62,18 +62,14 @@ impl Disk for DiskATA {
 
         let mut sector: usize = 0;
         while sectors - sector >= 255 {
-            if let Err(err) = self.port.ata_dma(block + sector as u64, 255, false, &mut self.clb, &mut self.ctbas, &mut self.buf) {
-                return Err(err);
-            }
+            self.port.ata_dma(block + sector as u64, 255, false, &mut self.clb, &mut self.ctbas, &mut self.buf)?;
 
             unsafe { ptr::copy(self.buf.as_ptr(), buffer.as_mut_ptr().offset(sector as isize * 512), 255 * 512); }
 
             sector += 255;
         }
         if sector < sectors {
-            if let Err(err) = self.port.ata_dma(block + sector as u64, sectors - sector, false, &mut self.clb, &mut self.ctbas, &mut self.buf) {
-                return Err(err);
-            }
+            self.port.ata_dma(block + sector as u64, sectors - sector, false, &mut self.clb, &mut self.ctbas, &mut self.buf)?;
 
             unsafe { ptr::copy(self.buf.as_ptr(), buffer.as_mut_ptr().offset(sector as isize * 512), (sectors - sector) * 512); }
 
@@ -108,4 +104,8 @@ impl Disk for DiskATA {
 
         Ok(sector * 512)
     }
+
+    fn block_length(&mut self) -> Result<u32> {
+        Ok(512)
+    }
 }

ahcid/src/ahci/disk_atapi.rs

@@ -1,5 +1,7 @@
 #![allow(dead_code)]
 
+use std::ptr;
+
 use byteorder::{ByteOrder, BigEndian};
 
 use syscall::io::Dma;
@@ -9,6 +11,7 @@ use super::hba::{HbaPort, HbaCmdTable, HbaCmdHeader};
 use super::Disk;
 
 const SCSI_READ_CAPACITY: u8 = 0x25;
+const SCSI_READ10: u8 = 0x28;
 
 pub struct DiskATAPI {
     id: usize,
@@ -17,6 +20,8 @@ pub struct DiskATAPI {
     clb: Dma<[HbaCmdHeader; 32]>,
     ctbas: [Dma<HbaCmdTable>; 32],
     _fb: Dma<[u8; 256]>,
+    // Just using the same buffer size as DiskATA
+    // Although the sector size is different (and varies)
     buf: Dma<[u8; 256 * 512]>
 }
 
@@ -77,12 +82,48 @@ impl Disk for DiskATAPI {
         }
     }
 
-    fn read(&mut self, _block: u64, _buffer: &mut [u8]) -> Result<usize> {
-        Err(Error::new(ENOSYS))
+    fn read(&mut self, block: u64, buffer: &mut [u8]) -> Result<usize> {
+        // TODO: Handle audio CDs, which use special READ CD command
+ 
+        let blk_len = self.block_length()?;
+        let sectors = buffer.len() as u32 / blk_len;
+
+        fn read10_cmd(block: u32, count: u16) -> [u8; 16] {
+            let mut cmd = [0; 16];
+            cmd[0] = SCSI_READ10;
+            BigEndian::write_u32(&mut cmd[2..6], block as u32);
+            BigEndian::write_u16(&mut cmd[7..9], count as u16);
+            cmd
+        }
+
+        let mut sector = 0;
+        let buf_len = (256 * 512) / blk_len;
+        let buf_size = buf_len * blk_len;
+        while sectors - sector >= buf_len {
+            let cmd = read10_cmd(block as u32 + sector, buf_len as u16);
+            self.port.packet(&cmd, buf_size, &mut self.clb, &mut self.ctbas, &mut self.buf)?;
+
+            unsafe { ptr::copy(self.buf.as_ptr(), buffer.as_mut_ptr().offset(sector as isize * blk_len as isize), buf_size as usize); }
+
+            sector += blk_len;
+        }
+        if sector < sectors {
+            let cmd = read10_cmd(block as u32 + sector, (sectors - sector) as u16);
+            self.port.packet(&cmd, buf_size, &mut self.clb, &mut self.ctbas, &mut self.buf)?;
+
+            unsafe { ptr::copy(self.buf.as_ptr(), buffer.as_mut_ptr().offset(sector as isize * blk_len as isize), ((sectors - sector) * blk_len) as usize); }
+
+            sector += sectors - sector;
+        }
+
+        Ok((sector * blk_len) as usize)
     }
 
     fn write(&mut self, _block: u64, _buffer: &[u8]) -> Result<usize> {
         Err(Error::new(ENOSYS)) // TODO: Implement writting
     }
     
+    fn block_length(&mut self) -> Result<u32> {
+        Ok(self.read_capacity()?.1)
+    }
 }

ahcid/src/ahci/mod.rs

@@ -15,6 +15,7 @@ pub trait Disk {
     fn size(&mut self) -> u64;
     fn read(&mut self, block: u64, buffer: &mut [u8]) -> Result<usize>;
     fn write(&mut self, block: u64, buffer: &[u8]) -> Result<usize>;
+    fn block_length(&mut self) -> Result<u32>;
 }
 
 pub fn disks(base: usize, name: &str) -> Vec<Box<Disk>> {

ahcid/src/scheme.rs

@@ -150,7 +150,8 @@ impl Scheme for DiskScheme {
             },
             Handle::Disk(ref mut handle, ref mut size, _) => {
                 let mut disk = handle.lock();
-                let count = disk.read((*size as u64)/512, buf)?;
+                let blk_len = disk.block_length()?;
+                let count = disk.read((*size as u64)/(blk_len as u64), buf)?;
                 *size += count;
                 Ok(count)
             }
@@ -165,7 +166,8 @@ impl Scheme for DiskScheme {
             },
             Handle::Disk(ref mut handle, ref mut size, _) => {
                 let mut disk = handle.lock();
-                let count = disk.write((*size as u64)/512, buf)?;
+                let blk_len = disk.block_length()?;
+                let count = disk.write((*size as u64)/(blk_len as u64), buf)?;
                 *size += count;
                 Ok(count)
             }