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/* ----------------------------------------------------------------------- *
*
* 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;
}
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