diff options
Diffstat (limited to 'contrib/syslinux-4.02/com32/gpllib/disk/geom.c')
| -rw-r--r-- | contrib/syslinux-4.02/com32/gpllib/disk/geom.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/com32/gpllib/disk/geom.c b/contrib/syslinux-4.02/com32/gpllib/disk/geom.c new file mode 100644 index 0000000..9e673ed --- /dev/null +++ b/contrib/syslinux-4.02/com32/gpllib/disk/geom.c @@ -0,0 +1,271 @@ +/* ----------------------------------------------------------------------- * + * + * Copyright 2009 Pierre-Alexandre Meyer + * + * Some parts borrowed from chain.c32: + * + * Copyright 2003-2009 H. Peter Anvin - All Rights Reserved + * Copyright 2009 Intel Corporation; author: H. Peter Anvin + * + * This file is part of Syslinux, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +#include <com32.h> +#include <string.h> +#include <stdio.h> +#include <disk/geom.h> + +#include <stdio.h> + +/** + * lba_to_chs - split given lba into cylinders/heads/sectors + **/ +void lba_to_chs(const struct driveinfo *drive_info, const int lba, + unsigned int *cylinder, unsigned int *head, + unsigned int *sector) +{ + unsigned int track; + + /* Use EDD, if valid */ + if (drive_info->edd_params.sectors_per_track > 0 && + drive_info->edd_params.heads > 0) { + *cylinder = (lba % drive_info->edd_params.sectors_per_track) + 1; + track = lba / drive_info->edd_params.sectors_per_track; + *head = track % drive_info->edd_params.heads; + *sector = track / drive_info->edd_params.heads; + } else if (drive_info->cbios) { + *cylinder = (lba % drive_info->legacy_sectors_per_track) + 1; + track = lba / drive_info->legacy_sectors_per_track; + *head = track % (drive_info->legacy_max_head + 1); + *sector = track / (drive_info->legacy_max_head + 1); + } +} + +/** + * detect_extensions - detect if we can use extensions + * + * INT 13 - IBM/MS INT 13 Extensions - INSTALLATION CHECK + * AH = 41h + * BX = 55AAh + * DL = drive (80h-FFh) + * + * Return: CF set on error (extensions not supported) + * AH = 01h (invalid function) + * CF clear if successful + * BX = AA55h if installed + * AH = major version of extensions + * 01h = 1.x + * 20h = 2.0 / EDD-1.0 + * 21h = 2.1 / EDD-1.1 + * 30h = EDD-3.0 + * AL = internal use + * CX = API subset support bitmap (see #00271) + * DH = extension version (v2.0+ ??? -- not present in 1.x) + * + * Note: the Phoenix Enhanced Disk Drive Specification v1.0 uses version 2.0 of + * the INT 13 Extensions API + * + * Bitfields for IBM/MS INT 13 Extensions API support bitmap: + * Bit(s) Description (Table 00271) + * 0 extended disk access functions (AH=42h-44h,47h,48h) supported + * 1 removable drive controller functions (AH=45h,46h,48h,49h,INT 15/AH=52h) + * supported + * 2 enhanced disk drive (EDD) functions (AH=48h,AH=4Eh) supported + * extended drive parameter table is valid (see #00273,#00278) + * 3-15 reserved (0) + **/ +static int detect_extensions(struct driveinfo *drive_info) +{ + com32sys_t getebios, ebios; + + memset(&getebios, 0, sizeof getebios); + memset(&ebios, 0, sizeof ebios); + + getebios.eflags.b[0] = 0x3; /* CF set */ + getebios.ebx.w[0] = 0x55aa; + getebios.edx.b[0] = drive_info->disk; + getebios.eax.b[1] = 0x41; + + __intcall(0x13, &getebios, &ebios); + + if (!(ebios.eflags.l & EFLAGS_CF) && ebios.ebx.w[0] == 0xaa55) { + drive_info->ebios = 1; + drive_info->edd_version = ebios.eax.b[1]; + drive_info->edd_functionality_subset = ebios.ecx.w[0]; + return 0; + } else + return -1; /* Drive does not exist? */ +} + +/** + * get_drive_parameters_with_extensions - retrieve disk parameters via AH=48h + * + * INT 13 - IBM/MS INT 13 Extensions - GET DRIVE PARAMETERS + * AH = 48h + * DL = drive (80h-FFh) + * DS:SI -> buffer for drive parameters + * Return: CF clear if successful + * AH = 00h + * DS:SI buffer filled + * CF set on error + * AH = error code (see #00234) + * BUG: several different Compaq BIOSes incorrectly report high-numbered + * drives (such as 90h, B0h, D0h, and F0h) as present, giving them the + * same geometry as drive 80h; as a workaround, scan through disk + * numbers, stopping as soon as the number of valid drives encountered + * equals the value in 0040h:0075h + **/ +static int get_drive_parameters_with_extensions(struct driveinfo *drive_info) +{ + com32sys_t inreg, outreg; + struct edd_device_parameters *dp = __com32.cs_bounce; + + memset(&inreg, 0, sizeof inreg); + + /* + * The caller shall set this value to the maximum Result Buffer + * length, in bytes. If the length of this buffer is less than 30 + * bytes, this function shall not return the pointer to Drive Parameter + * Table (DPT) extension. If the buffer length is 30 or greater on + * entry, it shall be set to 30 on exit. If the buffer length is + * between 26 and 29, it shall be set to 26 on exit. + * If the buffer length is less than 26 on entry an error shall be + * returned. + */ + dp->len = sizeof(struct edd_device_parameters); + + inreg.esi.w[0] = OFFS(dp); + inreg.ds = SEG(dp); + inreg.edx.b[0] = drive_info->disk; + inreg.eax.b[1] = 0x48; + + __intcall(0x13, &inreg, &outreg); + + /* CF set on error */ + if (outreg.eflags.l & EFLAGS_CF) + return outreg.eax.b[1]; + + memcpy(&drive_info->edd_params, dp, sizeof drive_info->edd_params); + + return 0; +} + +/** + * get_drive_parameters_without_extensions - retrieve drive parameters via AH=08h + * + * INT 13 - DISK - GET DRIVE PARAMETERS (PC,XT286,CONV,PS,ESDI,SCSI) + * AH = 08h + * DL = drive (bit 7 set for hard disk) + * + * Return: CF set on error + * AH = status (07h) (see #00234) + * CF clear if successful + * AH = 00h + * AL = 00h on at least some BIOSes + * BL = drive type (AT/PS2 floppies only) (see #00242) + * CH = low eight bits of maximum cylinder number + * CL = maximum sector number (bits 5-0) + * high two bits of maximum cylinder number (bits 7-6) + * DH = maximum head number + * DL = number of drives + * ES:DI -> drive parameter table (floppies only) + * + * Notes: + * - may return successful even though specified drive is greater than the + * number of attached drives of that type (floppy/hard); check DL to + * ensure validity + * - for systems predating the IBM AT, this call is only valid for hard + * disks, as it is implemented by the hard disk BIOS rather than the + * ROM BIOS + * - Toshiba laptops with HardRAM return DL=02h when called with DL=80h, + * but fail on DL=81h. The BIOS data at 40h:75h correctly reports 01h. + * may indicate only two drives present even if more are attached; to + * ensure a correct count, one can use AH=15h to scan through possible + * drives + * - for BIOSes which reserve the last cylinder for testing purposes, the + * cylinder count is automatically decremented + * on PS/1s with IBM ROM DOS 4, nonexistent drives return CF clear, + * BX=CX=0000h, and ES:DI = 0000h:0000h + * - the PC-Tools PCFORMAT program requires that AL=00h before it will + * proceed with the formatting + * + * BUG: several different Compaq BIOSes incorrectly report high-numbered + * drives (such as 90h, B0h, D0h, and F0h) as present, giving them the + * same geometry as drive 80h; as a workaround, scan through disk + * numbers, stopping as soon as the number of valid drives encountered + * equals the value in 0040h:0075h + * + * SeeAlso: AH=06h"Adaptec",AH=13h"SyQuest",AH=48h,AH=15h,INT 1E + * SeeAlso: INT 41"HARD DISK 0" + **/ +static int get_drive_parameters_without_extensions(struct driveinfo *drive_info) +{ + com32sys_t getparm, parm; + + memset(&getparm, 0, sizeof getparm); + memset(&parm, 0, sizeof parm); + + /* Ralf Brown recommends setting ES:DI to 0:0 */ + getparm.esi.w[0] = 0; + getparm.ds = 0; + getparm.edx.b[0] = drive_info->disk; + getparm.eax.b[1] = 0x08; + + __intcall(0x13, &getparm, &parm); + + /* CF set on error */ + if (parm.eflags.l & EFLAGS_CF) + return parm.eax.b[1]; + + /* DL contains the maximum drive number (it starts at 0) */ + drive_info->legacy_max_drive = parm.edx.b[0]; + + // XXX broken + /* Drive specified greater than the bumber of attached drives */ + //if (drive_info->disk > drive_info->drives) + // return -1; + + drive_info->legacy_type = parm.ebx.b[0]; + + /* DH contains the maximum head number (it starts at 0) */ + drive_info->legacy_max_head = parm.edx.b[1]; + + /* Maximum sector number (bits 5-0) per track */ + drive_info->legacy_sectors_per_track = parm.ecx.b[0] & 0x3f; + + /* + * Maximum cylinder number: + * CH = low eight bits of maximum cylinder number + * CL = high two bits of maximum cylinder number (bits 7-6) + */ + drive_info->legacy_max_cylinder = parm.ecx.b[1] + + ((parm.ecx.b[0] & 0xc0) << 2); + + if (drive_info->legacy_sectors_per_track > 0) + drive_info->cbios = 1; /* Valid geometry */ + + return 0; +} + +/** + * get_drive_parameters - retrieve drive parameters + * @drive_info: driveinfo structure to fill + **/ +int get_drive_parameters(struct driveinfo *drive_info) +{ + int return_code; + + if (detect_extensions(drive_info)) + return -1; + + return_code = get_drive_parameters_without_extensions(drive_info); + + /* If geometry isn't valid, no need to try to get more info about the drive */ + /* Looks like in can confuse some optical drives */ + if (drive_info->ebios && drive_info->cbios) + get_drive_parameters_with_extensions(drive_info); + + return return_code; +} |