/* ----------------------------------------------------------------------- * * * 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 #include #include #include #include /** * 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; }