losp/x86-pc/ata.lisp

   1 ;;;; Movitz ATA Hard Drive Driver
   2 ;;;; --------------------------------------------------------------------------
   3 ;;;; [23 Feb 2008]  Martin Bealby
   4 ;;;;   Read / write sector functions converted to work with lists of bytes
   5 ;;;; [25 Oct 2007]  Martin Bealby
   6 ;;;;   Rewritten from scratch based on http://www.osdever.net/tutorials/lba.php
   7 ;;;; --------------------------------------------------------------------------
   8
   9
  10 ;;;; --------------------------------------------------------------------------
  11 ;;;; Package Setup
  12 ;;;; --------------------------------------------------------------------------
  13 (require :x86-pc/package)
  14 (provide :x86-pc/ata)
  15
  16 (in-package muerte.x86-pc)
  17
  18
  19 ;;;; --------------------------------------------------------------------------
  20 ;;;; Constants
  21 ;;;; --------------------------------------------------------------------------
  22 (defconstant +ata-controller0+ #x1F0)
  23 (defconstant +ata-controller1+ #x170)
  24
  25 (defconstant +ata-offset-data+ 0)
  26 (defconstant +ata-offset-error-precomp+ 1)
  27 (defconstant +ata-offset-sector-count+ 2)
  28 (defconstant +ata-offset-lba1+ 3)
  29 (defconstant +ata-offset-lba2+ 4)
  30 (defconstant +ata-offset-lba3+ 5)
  31 (defconstant +ata-offset-drive-head+ 6)
  32 (defconstant +ata-offset-status-command+ 7)
  33
  34
  35 (defconstant +ata-command-read+ #x20)
  36 (defconstant +ata-command-write+ #x30)
  37 (defconstant +ata-bitflag-busy+ 7)
  38
  39
  40 ;;;; --------------------------------------------------------------------------
  41 ;;;; Functions
  42 ;;;; --------------------------------------------------------------------------
  43 (defun ata-busy-wait (ata-controller)
  44   "ATA Driver busy spin loop."
  45   (loop while (logbitp +ata-bitflag-busy+
  46                                            (io-port (+ ata-controller
  47                                                                    +ata-offset-status-command+)
  48                                                                 :unsigned-byte8))))
  49
  50 (defun ata-send-command (ata-controller command)
  51   "Send a command to an IDE controller."
  52   (setf (io-port (+ ata-controller +ata-offset-status-command+) :unsigned-byte8)
  53                 command))
  54
  55 (defun ata-lba-read-write-common (ata-controller drive-number block-address)
  56   ;; send a null
  57   (setf (io-port (+ ata-controller
  58                                         +ata-offset-error-precomp+) :unsigned-byte8) 0)
  59   ;; send a sector count
  60   (setf (io-port (+ ata-controller
  61                                         +ata-offset-sector-count+):unsigned-byte8) 1)
  62   ;; send the lowest 8 bits of the lba
  63   (setf (io-port (+ ata-controller +ata-offset-lba1+) :unsigned-byte8)
  64                 (logand block-address #xFF))
  65   ;; send the next 8 bits
  66   (setf (io-port (+ ata-controller +ata-offset-lba2+) :unsigned-byte8)
  67                 (ash (logand block-address #xFF00)
  68                          -8))
  69   ;; send the next 8 bits
  70   (setf (io-port (+ ata-controller +ata-offset-lba3+) :unsigned-byte8)
  71                 (ash (logand block-address #xFF0000)
  72                          -16))
  73   ;; send the last 4 bits and some magic bits
  74   (setf (io-port (+ ata-controller +ata-offset-drive-head+) :unsigned-byte8)
  75                 (logand
  76                  (logior (ash (logand block-address #xF000000)
  77                                           -24)
  78                                  #xE0  ;; magic
  79                                  (ash drive-number 4))
  80                  #x0F)))
  81
  82 (defun ata-lba-read-sector (ata-controller drive-number block-address)
  83   "Reads a specified sector of data from the disk."
  84   ;; Call common initialisation
  85   (ata-lba-read-write-common ata-controller drive-number block-address)
  86   ;; send read command
  87   (ata-send-command ata-controller +ata-command-read+)
  88   ;; wait for the drive
  89   (ata-busy-wait ata-controller)
  90   ;; read the data
  91   (loop for position from 0 to 255
  92          for data = (io-port (+ ata-controller +ata-offset-data+)
  93                                                    :unsigned-byte16)
  94      collect (logand #x00FF data)
  95          collect (ash (logand #xFF00 data) -8)))
  96
  97
  98 (defun ata-lba-write-sector (ata-controller drive-number block-address data)
  99   "Writes data to a sector of the disk."
 100   ;; data must be a list of 512 unsigned-byte8's
 101   ;; based upon ata-lba-read-sector-above
 102   (ata-lba-read-write-common ata-controller drive-number block-address)
 103   (ata-send-command ata-controller +ata-command-write+)
 104   (ata-busy-wait ata-controller)
 105   (loop for position from 0 to 511 by 2
 106          do (setf (io-port (+ ata-controller +ata-offset-data+) :unsigned-byte16)
 107                           (+ (ash (nth position data) 8)
 108                                  (nth (+ 1 position) data)))))