com32/gpllib/disk/geom.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2009 Pierre-Alexandre Meyer
   4  *
   5  *   Some parts borrowed from chain.c32:
   6  *
   7  *   Copyright 2003-2009 H. Peter Anvin - All Rights Reserved
   8  *   Copyright 2009 Intel Corporation; author: H. Peter Anvin
   9  *
  10  *   This file is part of Syslinux, and is made available under
  11  *   the terms of the GNU General Public License version 2.
  12  *
  13  * ----------------------------------------------------------------------- */
  14
  15 #include <com32.h>
  16 #include <string.h>
  17 #include <stdio.h>
  18 #include <disk/geom.h>
  19
  20 #include <stdio.h>
  21
  22 /**
  23  * lba_to_chs - split given lba into cylinders/heads/sectors
  24  **/
  25 void lba_to_chs(const struct driveinfo *drive_info, const int lba,
  26                 unsigned int *cylinder, unsigned int *head,
  27                 unsigned int *sector)
  28 {
  29     unsigned int track;
  30
  31     /* Use EDD, if valid */
  32     if (drive_info->edd_params.sectors_per_track > 0 &&
  33         drive_info->edd_params.heads > 0) {
  34         *cylinder = (lba % drive_info->edd_params.sectors_per_track) + 1;
  35         track = lba / drive_info->edd_params.sectors_per_track;
  36         *head = track % drive_info->edd_params.heads;
  37         *sector = track / drive_info->edd_params.heads;
  38     } else if (drive_info->cbios) {
  39         *cylinder = (lba % drive_info->legacy_sectors_per_track) + 1;
  40         track = lba / drive_info->legacy_sectors_per_track;
  41         *head = track % (drive_info->legacy_max_head + 1);
  42         *sector = track / (drive_info->legacy_max_head + 1);
  43     }
  44 }
  45
  46 /**
  47  * detect_extensions - detect if we can use extensions
  48  *
  49  * INT 13 - IBM/MS INT 13 Extensions - INSTALLATION CHECK
  50  *    AH = 41h
  51  *    BX = 55AAh
  52  *    DL = drive (80h-FFh)
  53  *
  54  * Return: CF set on error (extensions not supported)
  55  *    AH = 01h (invalid function)
  56  *    CF clear if successful
  57  *    BX = AA55h if installed
  58  *    AH = major version of extensions
  59  *        01h = 1.x
  60  *        20h = 2.0 / EDD-1.0
  61  *        21h = 2.1 / EDD-1.1
  62  *        30h = EDD-3.0
  63  *    AL = internal use
  64  *    CX = API subset support bitmap (see #00271)
  65  *    DH = extension version (v2.0+ ??? -- not present in 1.x)
  66  *
  67  * Note: the Phoenix Enhanced Disk Drive Specification v1.0 uses version 2.0 of
  68  *       the INT 13 Extensions API
  69  *
  70  * Bitfields for IBM/MS INT 13 Extensions API support bitmap:
  71  * Bit(s)    Description    (Table 00271)
  72  *     0 extended disk access functions (AH=42h-44h,47h,48h) supported
  73  *     1 removable drive controller functions (AH=45h,46h,48h,49h,INT 15/AH=52h)
  74  *       supported
  75  *     2 enhanced disk drive (EDD) functions (AH=48h,AH=4Eh) supported
  76  *       extended drive parameter table is valid (see #00273,#00278)
  77  *     3-15    reserved (0)
  78  **/
  79 static int detect_extensions(struct driveinfo *drive_info)
  80 {
  81     com32sys_t getebios, ebios;
  82
  83     memset(&getebios, 0, sizeof getebios);
  84     memset(&ebios, 0, sizeof ebios);
  85
  86     getebios.eflags.b[0] = 0x3; /* CF set */
  87     getebios.ebx.w[0] = 0x55aa;
  88     getebios.edx.b[0] = drive_info->disk;
  89     getebios.eax.b[1] = 0x41;
  90
  91     __intcall(0x13, &getebios, &ebios);
  92
  93     if (!(ebios.eflags.l & EFLAGS_CF) && ebios.ebx.w[0] == 0xaa55) {
  94         drive_info->ebios = 1;
  95         drive_info->edd_version = ebios.eax.b[1];
  96         drive_info->edd_functionality_subset = ebios.ecx.w[0];
  97         return 0;
  98     } else
  99         return -1;              /* Drive does not exist? */
 100 }
 101
 102 /**
 103  * get_drive_parameters_with_extensions - retrieve disk parameters via AH=48h
 104  *
 105  * INT 13 - IBM/MS INT 13 Extensions - GET DRIVE PARAMETERS
 106  *     AH = 48h
 107  *     DL = drive (80h-FFh)
 108  *     DS:SI -> buffer for drive parameters
 109  * Return: CF clear if successful
 110  *     AH = 00h
 111  *     DS:SI buffer filled
 112  *     CF set on error
 113  *     AH = error code (see #00234)
 114  * BUG: several different Compaq BIOSes incorrectly report high-numbered
 115  *     drives (such as 90h, B0h, D0h, and F0h) as present, giving them the
 116  *     same geometry as drive 80h; as a workaround, scan through disk
 117  *     numbers, stopping as soon as the number of valid drives encountered
 118  *     equals the value in 0040h:0075h
 119  **/
 120 static int get_drive_parameters_with_extensions(struct driveinfo *drive_info)
 121 {
 122     com32sys_t inreg, outreg;
 123     struct edd_device_parameters *dp = __com32.cs_bounce;
 124
 125     memset(&inreg, 0, sizeof inreg);
 126
 127     /*
 128      * The caller shall set this value to the maximum Result Buffer
 129      * length, in bytes. If the length of this buffer is less than 30
 130      * bytes, this function shall not return the pointer to Drive Parameter
 131      * Table (DPT) extension. If the buffer length is 30 or greater on
 132      * entry, it shall be set to 30 on exit. If the buffer length is
 133      * between 26 and 29, it shall be set to 26 on exit.
 134      * If the buffer length is less than 26 on entry an error shall be
 135      * returned.
 136      */
 137     dp->len = sizeof(struct edd_device_parameters);
 138
 139     inreg.esi.w[0] = OFFS(dp);
 140     inreg.ds = SEG(dp);
 141     inreg.edx.b[0] = drive_info->disk;
 142     inreg.eax.b[1] = 0x48;
 143
 144     __intcall(0x13, &inreg, &outreg);
 145
 146     /* CF set on error */
 147     if (outreg.eflags.l & EFLAGS_CF)
 148         return outreg.eax.b[1];
 149
 150     memcpy(&drive_info->edd_params, dp, sizeof drive_info->edd_params);
 151
 152     return 0;
 153 }
 154
 155 /**
 156  * get_drive_parameters_without_extensions - retrieve drive parameters via AH=08h
 157  *
 158  * INT 13 - DISK - GET DRIVE PARAMETERS (PC,XT286,CONV,PS,ESDI,SCSI)
 159  *     AH = 08h
 160  *     DL = drive (bit 7 set for hard disk)
 161  *
 162  * Return: CF set on error
 163  *     AH = status (07h) (see #00234)
 164  *     CF clear if successful
 165  *     AH = 00h
 166  *     AL = 00h on at least some BIOSes
 167  *     BL = drive type (AT/PS2 floppies only) (see #00242)
 168  *     CH = low eight bits of maximum cylinder number
 169  *     CL = maximum sector number (bits 5-0)
 170  *          high two bits of maximum cylinder number (bits 7-6)
 171  *     DH = maximum head number
 172  *     DL = number of drives
 173  *     ES:DI -> drive parameter table (floppies only)
 174  *
 175  * Notes:
 176  *   - may return successful even though specified drive is greater than the
 177  *     number of attached drives of that type (floppy/hard); check DL to
 178  *     ensure validity
 179  *   - for systems predating the IBM AT, this call is only valid for hard
 180  *     disks, as it is implemented by the hard disk BIOS rather than the
 181  *     ROM BIOS
 182  *   - Toshiba laptops with HardRAM return DL=02h when called with DL=80h,
 183  *     but fail on DL=81h. The BIOS data at 40h:75h correctly reports 01h.
 184  *     may indicate only two drives present even if more are attached; to
 185  *     ensure a correct count, one can use AH=15h to scan through possible
 186  *     drives
 187  *   - for BIOSes which reserve the last cylinder for testing purposes, the
 188  *     cylinder count is automatically decremented
 189  *     on PS/1s with IBM ROM DOS 4, nonexistent drives return CF clear,
 190  *     BX=CX=0000h, and ES:DI = 0000h:0000h
 191  *   - the PC-Tools PCFORMAT program requires that AL=00h before it will
 192  *     proceed with the formatting
 193  *
 194  * BUG: several different Compaq BIOSes incorrectly report high-numbered
 195  *      drives (such as 90h, B0h, D0h, and F0h) as present, giving them the
 196  *      same geometry as drive 80h; as a workaround, scan through disk
 197  *      numbers, stopping as soon as the number of valid drives encountered
 198  *      equals the value in 0040h:0075h
 199  *
 200  * SeeAlso: AH=06h"Adaptec",AH=13h"SyQuest",AH=48h,AH=15h,INT 1E
 201  * SeeAlso: INT 41"HARD DISK 0"
 202  **/
 203 static int get_drive_parameters_without_extensions(struct driveinfo *drive_info)
 204 {
 205     com32sys_t getparm, parm;
 206
 207     memset(&getparm, 0, sizeof getparm);
 208     memset(&parm, 0, sizeof parm);
 209
 210     /* Ralf Brown recommends setting ES:DI to 0:0 */
 211     getparm.esi.w[0] = 0;
 212     getparm.ds = 0;
 213     getparm.edx.b[0] = drive_info->disk;
 214     getparm.eax.b[1] = 0x08;
 215
 216     __intcall(0x13, &getparm, &parm);
 217
 218     /* CF set on error */
 219     if (parm.eflags.l & EFLAGS_CF)
 220         return parm.eax.b[1];
 221
 222     /* DL contains the maximum drive number (it starts at 0) */
 223     drive_info->legacy_max_drive = parm.edx.b[0];
 224
 225     // XXX broken
 226     /* Drive specified greater than the bumber of attached drives */
 227     //if (drive_info->disk > drive_info->drives)
 228     //      return -1;
 229
 230     drive_info->legacy_type = parm.ebx.b[0];
 231
 232     /* DH contains the maximum head number (it starts at 0) */
 233     drive_info->legacy_max_head = parm.edx.b[1];
 234
 235     /* Maximum sector number (bits 5-0) per track */
 236     drive_info->legacy_sectors_per_track = parm.ecx.b[0] & 0x3f;
 237
 238     /*
 239      * Maximum cylinder number:
 240      *     CH = low eight bits of maximum cylinder number
 241      *     CL = high two bits of maximum cylinder number (bits 7-6)
 242      */
 243     drive_info->legacy_max_cylinder = parm.ecx.b[1] +
 244         ((parm.ecx.b[0] & 0xc0) << 2);
 245
 246     if (drive_info->legacy_sectors_per_track > 0)
 247         drive_info->cbios = 1;  /* Valid geometry */
 248
 249     return 0;
 250 }
 251
 252 /**
 253  * get_drive_parameters - retrieve drive parameters
 254  * @drive_info:         driveinfo structure to fill
 255  **/
 256 int get_drive_parameters(struct driveinfo *drive_info)
 257 {
 258     int return_code;
 259
 260     if (detect_extensions(drive_info))
 261         return -1;
 262
 263     return_code = get_drive_parameters_without_extensions(drive_info);
 264
 265     /* If geometry isn't valid, no need to try to get more info about the drive */
 266     /* Looks like in can confuse some optical drives */
 267     if (drive_info->ebios && drive_info->cbios)
 268         get_drive_parameters_with_extensions(drive_info);
 269
 270     return return_code;
 271 }