src/arch/i386/include/int13.h

   1 #ifndef INT13_H
   2 #define INT13_H
   3
   4 /** @file
   5  *
   6  * INT 13 emulation
   7  *
   8  */
   9
  10 FILE_LICENCE ( GPL2_OR_LATER );
  11
  12 #include <stdint.h>
  13 #include <gpxe/list.h>
  14 #include <realmode.h>
  15
  16 struct block_device;
  17
  18 /**
  19  * @defgroup int13ops INT 13 operation codes
  20  * @{
  21  */
  22
  23 /** Reset disk system */
  24 #define INT13_RESET                     0x00
  25 /** Get status of last operation */
  26 #define INT13_GET_LAST_STATUS           0x01
  27 /** Read sectors */
  28 #define INT13_READ_SECTORS              0x02
  29 /** Write sectors */
  30 #define INT13_WRITE_SECTORS             0x03
  31 /** Get drive parameters */
  32 #define INT13_GET_PARAMETERS            0x08
  33 /** Get disk type */
  34 #define INT13_GET_DISK_TYPE             0x15
  35 /** Extensions installation check */
  36 #define INT13_EXTENSION_CHECK           0x41
  37 /** Extended read */
  38 #define INT13_EXTENDED_READ             0x42
  39 /** Extended write */
  40 #define INT13_EXTENDED_WRITE            0x43
  41 /** Get extended drive parameters */
  42 #define INT13_GET_EXTENDED_PARAMETERS   0x48
  43 /** Get CD-ROM status / terminate emulation */
  44 #define INT13_CDROM_STATUS_TERMINATE    0x4b
  45
  46 /** @} */
  47
  48 /**
  49  * @defgroup int13status INT 13 status codes
  50  * @{
  51  */
  52
  53 /** Operation completed successfully */
  54 #define INT13_STATUS_SUCCESS            0x00
  55 /** Invalid function or parameter */
  56 #define INT13_STATUS_INVALID            0x01
  57 /** Read error */
  58 #define INT13_STATUS_READ_ERROR         0x04
  59 /** Write error */
  60 #define INT13_STATUS_WRITE_ERROR        0xcc
  61
  62 /** @} */
  63
  64 /** Block size for non-extended INT 13 calls */
  65 #define INT13_BLKSIZE 512
  66
  67 /** An INT 13 emulated drive */
  68 struct int13_drive {
  69         /** List of all registered drives */
  70         struct list_head list;
  71
  72         /** Underlying block device */
  73         struct block_device *blockdev;
  74
  75         /** BIOS in-use drive number (0x80-0xff) */
  76         unsigned int drive;
  77         /** BIOS natural drive number (0x80-0xff)
  78          *
  79          * This is the drive number that would have been assigned by
  80          * 'naturally' appending the drive to the end of the BIOS
  81          * drive list.
  82          *
  83          * If the emulated drive replaces a preexisting drive, this is
  84          * the drive number that the preexisting drive gets remapped
  85          * to.
  86          */
  87         unsigned int natural_drive;
  88
  89         /** Number of cylinders
  90          *
  91          * The cylinder number field in an INT 13 call is ten bits
  92          * wide, giving a maximum of 1024 cylinders.  Conventionally,
  93          * when the 7.8GB limit of a CHS address is exceeded, it is
  94          * the number of cylinders that is increased beyond the
  95          * addressable limit.
  96          */
  97         unsigned int cylinders;
  98         /** Number of heads
  99          *
 100          * The head number field in an INT 13 call is eight bits wide,
 101          * giving a maximum of 256 heads.  However, apparently all
 102          * versions of MS-DOS up to and including Win95 fail with 256
 103          * heads, so the maximum encountered in practice is 255.
 104          */
 105         unsigned int heads;
 106         /** Number of sectors per track
 107          *
 108          * The sector number field in an INT 13 call is six bits wide,
 109          * giving a maximum of 63 sectors, since sector numbering
 110          * (unlike head and cylinder numbering) starts at 1, not 0.
 111          */
 112         unsigned int sectors_per_track;
 113
 114         /** Status of last operation */
 115         int last_status;
 116 };
 117
 118 /** An INT 13 disk address packet */
 119 struct int13_disk_address {
 120         /** Size of the packet, in bytes */
 121         uint8_t bufsize;
 122         /** Reserved, must be zero */
 123         uint8_t reserved;
 124         /** Block count */
 125         uint16_t count;
 126         /** Data buffer */
 127         struct segoff buffer;
 128         /** Starting block number */
 129         uint64_t lba;
 130         /** Data buffer (EDD-3.0 only) */
 131         uint64_t buffer_phys;
 132 } __attribute__ (( packed ));
 133
 134 /** INT 13 disk parameters */
 135 struct int13_disk_parameters {
 136         /** Size of this structure */
 137         uint16_t bufsize;
 138         /** Flags */
 139         uint16_t flags;
 140         /** Number of cylinders */
 141         uint32_t cylinders;
 142         /** Number of heads */
 143         uint32_t heads;
 144         /** Number of sectors per track */
 145         uint32_t sectors_per_track;
 146         /** Total number of sectors on drive */
 147         uint64_t sectors;
 148         /** Bytes per sector */
 149         uint16_t sector_size;
 150
 151 } __attribute__ (( packed ));
 152
 153 /**
 154  * @defgroup int13types INT 13 disk types
 155  * @{
 156  */
 157
 158 /** No such drive */
 159 #define INT13_DISK_TYPE_NONE    0x00
 160 /** Floppy without change-line support */
 161 #define INT13_DISK_TYPE_FDD     0x01
 162 /** Floppy with change-line support */
 163 #define INT13_DISK_TYPE_FDD_CL  0x02
 164 /** Hard disk */
 165 #define INT13_DISK_TYPE_HDD     0x03
 166
 167 /** @} */
 168
 169 /**
 170  * @defgroup int13flags INT 13 disk parameter flags
 171  * @{
 172  */
 173
 174 /** DMA boundary errors handled transparently */
 175 #define INT13_FL_DMA_TRANSPARENT 0x01
 176 /** CHS information is valid */
 177 #define INT13_FL_CHS_VALID       0x02
 178 /** Removable drive */
 179 #define INT13_FL_REMOVABLE       0x04
 180 /** Write with verify supported */
 181 #define INT13_FL_VERIFIABLE      0x08
 182 /** Has change-line supported (valid only for removable drives) */
 183 #define INT13_FL_CHANGE_LINE     0x10
 184 /** Drive can be locked (valid only for removable drives) */
 185 #define INT13_FL_LOCKABLE        0x20
 186 /** CHS is max possible, not current media (valid only for removable drives) */
 187 #define INT13_FL_CHS_MAX         0x40
 188
 189 /** @} */
 190
 191 /**
 192  * @defgroup int13exts INT 13 extension flags
 193  * @{
 194  */
 195
 196 /** Extended disk access functions supported */
 197 #define INT13_EXTENSION_LINEAR          0x01
 198 /** Removable drive functions supported */
 199 #define INT13_EXTENSION_REMOVABLE       0x02
 200 /** EDD functions supported */
 201 #define INT13_EXTENSION_EDD             0x04
 202
 203 /** @} */
 204
 205 /**
 206  * @defgroup int13vers INT 13 extension versions
 207  * @{
 208  */
 209
 210 /** INT13 extensions version 1.x */
 211 #define INT13_EXTENSION_VER_1_X         0x01
 212 /** INT13 extensions version 2.0 (EDD-1.0) */
 213 #define INT13_EXTENSION_VER_2_0         0x20
 214 /** INT13 extensions version 2.1 (EDD-1.1) */
 215 #define INT13_EXTENSION_VER_2_1         0x21
 216 /** INT13 extensions version 3.0 (EDD-3.0) */
 217 #define INT13_EXTENSION_VER_3_0         0x30
 218
 219 /** @} */
 220
 221 /** Bootable CD-ROM specification packet */
 222 struct int13_cdrom_specification {
 223         /** Size of packet in bytes */
 224         uint8_t size;
 225         /** Boot media type */
 226         uint8_t media_type;
 227         /** Drive number */
 228         uint8_t drive;
 229         /** CD-ROM controller number */
 230         uint8_t controller;
 231         /** LBA of disk image to emulate */
 232         uint32_t lba;
 233         /** Device specification */
 234         uint16_t device;
 235         /** Segment of 3K buffer for caching CD-ROM reads */
 236         uint16_t cache_segment;
 237         /** Load segment for initial boot image */
 238         uint16_t load_segment;
 239         /** Number of 512-byte sectors to load */
 240         uint16_t load_sectors;
 241         /** Low 8 bits of cylinder number */
 242         uint8_t cyl;
 243         /** Sector number, plus high 2 bits of cylinder number */
 244         uint8_t cyl_sector;
 245         /** Head number */
 246         uint8_t head;
 247 } __attribute__ (( packed ));
 248
 249 /** A C/H/S address within a partition table entry */
 250 struct partition_chs {
 251         /** Head number */
 252         uint8_t head;
 253         /** Sector number, plus high 2 bits of cylinder number */
 254         uint8_t cyl_sector;
 255         /** Low 8 bits of cylinder number */
 256         uint8_t cyl;
 257 } __attribute__ (( packed ));
 258
 259 #define PART_HEAD(chs) ( (chs).head )
 260 #define PART_SECTOR(chs) ( (chs).cyl_sector & 0x3f )
 261 #define PART_CYLINDER(chs) ( (chs).cyl | ( ( (chs).cyl_sector & 0xc0 ) << 2 ) )
 262
 263 /** A partition table entry within the MBR */
 264 struct partition_table_entry {
 265         /** Bootable flag */
 266         uint8_t bootable;
 267         /** C/H/S start address */
 268         struct partition_chs chs_start;
 269         /** System indicator (partition type) */
 270         uint8_t type;
 271         /** C/H/S end address */
 272         struct partition_chs chs_end;
 273         /** Linear start address */
 274         uint32_t start;
 275         /** Linear length */
 276         uint32_t length;
 277 } __attribute__ (( packed ));
 278
 279 /** A Master Boot Record */
 280 struct master_boot_record {
 281         uint8_t pad[446];
 282         /** Partition table */
 283         struct partition_table_entry partitions[4];
 284         /** 0x55aa MBR signature */
 285         uint16_t signature;
 286 } __attribute__ (( packed ));
 287
 288 extern void register_int13_drive ( struct int13_drive *drive );
 289 extern void unregister_int13_drive ( struct int13_drive *drive );
 290 extern int int13_boot ( unsigned int drive );
 291
 292 #endif /* INT13_H */