Add read, write command structures

nvmed/src/nvme.rs

@@ -1,5 +1,64 @@
 use syscall::io::{Io, Mmio};
 
+pub struct NvmeCmd {
+    /// Command dword 0
+    cdw0: u32,
+    /// Namespace identifier
+    nsid: u32,
+    /// Reserved
+    _rsvd: u64,
+    /// Metadata pointer
+    mptr: u64,
+    /// Data pointer
+    dptr: [u64; 2],
+    /// Command dword 10
+    cdw10: u32,
+    /// Command dword 11
+    cdw11: u32,
+    /// Command dword 12
+    cdw12: u32,
+    /// Command dword 13
+    cdw13: u32,
+    /// Command dword 14
+    cdw14: u32,
+    /// Command dword 15
+    cdw15: u32,
+}
+
+impl NvmeCmd {
+    pub fn read(cid: u16, lba: u64, count: u16, dst: u64) -> Self {
+        NvmeCmd {
+            cdw0: (cid as u32) << 16 | 1 << 14 | 2,
+            nsid: 0xFFFFFFFF,
+            _rsvd: 0,
+            mptr: 0,
+            dptr: [dst, (count as u64) << 9],
+            cdw10: lba as u32,
+            cdw11: (lba >> 32) as u32,
+            cdw12: count as u32,
+            cdw13: 0,
+            cdw14: 0,
+            cdw15: 0,
+        }
+    }
+
+    pub fn write(cid: u16, lba: u64, count: u16, src: u64) -> Self {
+        NvmeCmd {
+            cdw0: (cid as u32) << 16 | 1 << 14 | 1,
+            nsid: 0xFFFFFFFF,
+            _rsvd: 0,
+            mptr: 0,
+            dptr: [src, (count as u64) << 9],
+            cdw10: lba as u32,
+            cdw11: (lba >> 32) as u32,
+            cdw12: count as u32,
+            cdw13: 0,
+            cdw14: 0,
+            cdw15: 0,
+        }
+    }
+}
+
 #[repr(packed)]
 pub struct NvmeRegs {
     /// Controller Capabilities
@@ -27,5 +86,5 @@ pub struct NvmeRegs {
     /// Controller memory buffer location
     cmbloc: Mmio<u32>,
     /// Controller memory buffer size
-    cmbsz: Mmio<u32>,    
-}
+    cmbsz: Mmio<u32>,
+}