source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/DetectDrives.asm@ 598

Last change on this file since 598 was 598, checked in by Tomi Tilli, 6 years ago

Windows 95 CMOS hack broke on last commit. Windows 95 DID require that CMOS byte 12h had drive 0 set. Drive 1 was not enough. Now there is detection for Award BIOSes and the CMOS hack won't be applied on those.

File size: 11.3 KB
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1; Project name : XTIDE Universal BIOS
2; Description : Functions for detecting drive for the BIOS.
3
4;
5; XTIDE Universal BIOS and Associated Tools
6; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
7;
8; This program is free software; you can redistribute it and/or modify
9; it under the terms of the GNU General Public License as published by
10; the Free Software Foundation; either version 2 of the License, or
11; (at your option) any later version.
12;
13; This program is distributed in the hope that it will be useful,
14; but WITHOUT ANY WARRANTY; without even the implied warranty of
15; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16; GNU General Public License for more details.
17; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
18;
19
20; Section containing code
21SECTION .text
22
23;--------------------------------------------------------------------
24; Detects all IDE hard disks to be controlled by this BIOS.
25;
26; DetectDrives_FromAllIDEControllers
27; Parameters:
28; DS: RAMVARS segment
29; ES: BDA segment (zero)
30; Returns:
31; Nothing
32; Corrupts registers:
33; All (not segments)
34;--------------------------------------------------------------------
35DetectDrives_FromAllIDEControllers:
36 call RamVars_GetIdeControllerCountToCX
37 mov bp, ROMVARS.ideVars0 ; CS:BP now points to first IDEVARS
38
39.DriveDetectLoop: ; Loop through IDEVARS
40 push cx
41
42 mov cx, g_szDetectMaster
43 mov bh, MASK_DRVNHEAD_SET ; Select Master drive
44 call StartDetectionWithDriveSelectByteInBHandStringInCX ; Detect and create DPT + BOOTNFO
45
46 mov cx, g_szDetectSlave
47 mov bh, MASK_DRVNHEAD_SET | FLG_DRVNHEAD_DRV
48 call StartDetectionWithDriveSelectByteInBHandStringInCX
49
50%ifdef MODULE_HOTKEYS
51%ifdef MODULE_SERIAL
52 ; This is only needed for hotkey F6 (ComDtct) to work
53 call ScanHotkeysFromKeyBufferAndStoreToBootvars ; Done here while CX is still protected
54%endif
55%endif
56
57 pop cx
58
59 add bp, BYTE IDEVARS_size ; Point to next IDEVARS
60
61%ifdef MODULE_SERIAL
62 jcxz .AddHardDisks ; Set to zero on .ideVarsSerialAuto iteration (if any)
63%endif
64 loop .DriveDetectLoop
65
66%ifdef MODULE_SERIAL
67;----------------------------------------------------------------------
68;
69; if serial drive detected, do not scan (avoids duplicate drives and isn't needed - we already have a connection)
70;
71 call FindDPT_ToDSDIforSerialDevice ; Does not modify AX
72 jnc .AddHardDisks
73
74 mov bp, ROMVARS.ideVarsSerialAuto ; Point to our special IDEVARS structure, just for serial scans
75
76%ifdef MODULE_HOTKEYS
77 cmp al, COM_DETECT_HOTKEY_SCANCODE ; Set by last call to ScanHotkeysFromKeyBufferAndStoreToBootvars above
78 je .DriveDetectLoop
79%endif
80
81 mov al, [cs:ROMVARS.wFlags] ; Configurator set to always scan?
82 or al, [es:BDA.bKBFlgs1] ; Or, did the user hold down the ALT key?
83 and al, 8 ; 8 = alt key depressed, same as FLG_ROMVARS_SERIAL_SCANDETECT
84 jnz .DriveDetectLoop
85%endif ; MODULE_SERIAL
86
87.AddHardDisks:
88;----------------------------------------------------------------------
89;
90; Add in hard disks to BDA, finalize our Count and First variables
91;
92; Note that we perform the add to bHDCount and store bFirstDrv even if the count is zero.
93; This is done because we use the value of .bFirstDrv to know how many drives were in the system
94; at the time of boot, and to return that number on int13h/8h calls. Because the count is zero,
95; FindDPT_ForDriveNumber will not find any drives that are ours.
96;
97
98; Here we might want to replace BIOS configured drives with the ones we detected.
99; Primary reason is to support dynamic overlay feature in the future. Second reason
100; is a hack to get Windows 95 load proper IDE drivers.
101;
102; The Windows hack has two parts. First part is to try to alter CMOS address 12h as that
103; is what Windows 95 driver reads to detect IDE drives. Altering is not possible on all
104; systems since CMOS has a checksum but its location is not standardized. We will first
105; try to detect valid checksum. If it succeeds, then it is safe to assume this system
106; has compatible CMOS and we can alter it.
107; If verify fails, we do the more dirty hack to zero BDA drive count. Then Windows 95 works
108; as long as user has configured at least one drive in the BIOS setup.
109
110%ifdef USE_AT ; FLG_ROMVARS_IGNORE_MOTHERBOARD_DRIVES is for AT builds only
111
112 %ifdef MODULE_WIN95_CMOS_HACK
113 mov dl, HARD_DISK_TYPES
114 call CMOS_ReadFromIndexInDLtoAL
115 test al, 0F0h
116 jnz SHORT .ClearBdaDriveCount ; CMOS byte 12h is ready for Windows 95
117 call CMOS_Verify10hTo2Dh ; Can we modify CMOS?
118 jnz SHORT .ClearBdaDriveCount ; Unsupported BIOS, use plan B
119
120 ; Now we can alter CMOS location 12h. Award BIOS locks if we set drive 0 type to Fh
121 ; (but accept changes to drive type 1). Windows 95 requires that the drive 0 type is
122 ; non zero and ignores drive 1 type. So if we only set drive 1, then Award BIOS
123 ; won't give problems but Windows 95 stays in MS-DOS compatibility mode.
124 ;
125 ; For Award BIOSes we could set the Drive 0 type to 1 and then clear the BDA drive count.
126 ; So essentially we could automatically do what user needs to do manually to get Windows 95
127 ; working on Award BIOSes. However, I think that should be left to do manually since
128 ; there may be SCSI drives on the system or FLG_ROMVARS_IGNORE_MOTHERBOARD_DRIVES could
129 ; be intentionally cleared and forcing the dummy drive might cause only trouble.
130
131 ; Try to detect Award BIOS (Seems to work on a tested 128k BIOS so hopefully
132 ; there will be no need to scan E000h segment)
133 mov cx, 65536 - 4
134 mov eax, 'Awar' ; Four characters should be enough
135 mov di, 0F000h ; Scan 64k starting from segment F000h
136 mov fs, di ; No need to preserve FS since we set it to zero soon when we boot
137 xor di, di
138 .ScanNextCharacters:
139 cmp [fs:di], eax
140 je SHORT .ClearBdaDriveCount ; Award detected, cannot modify CMOS
141 inc di ; Increment offset by one character (not four)
142 loop .ScanNextCharacters
143
144 ; Now it should be safe to write
145 mov dl, HARD_DISK_TYPES
146 mov al, 0F0h ; Drive 0 type 16...47 (supposed to be defined elsewhere in the CMOS)
147 call CMOS_WriteALtoIndexInDL
148 call CMOS_StoreNewChecksumFor10hto2Dh
149.ClearBdaDriveCount:
150 %endif ; MODULE_WIN95_CMOS_HACK
151
152 test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_IGNORE_MOTHERBOARD_DRIVES
153 jz SHORT .ContinueInitialization
154 mov BYTE [es:BDA.bHDCount], 0 ; Set hard disk count to zero
155.ContinueInitialization:
156%endif
157
158 mov cx, [RAMVARS.wDrvCntAndFlopCnt] ; Our count of hard disks
159 mov al, [es:BDA.bHDCount]
160 add [es:BDA.bHDCount], cl ; Add our drives to the system count
161 or al, 80h ; Or in hard disk flag
162 mov [RAMVARS.bFirstDrv], al ; Store first drive number
163
164.AddFloppies:
165%ifdef MODULE_SERIAL_FLOPPY
166;----------------------------------------------------------------------
167;
168; Add in any emulated serial floppy drives, finalize our packed Count and First variables
169;
170 dec ch
171 mov al, ch
172 js .NoFloppies ; if no drives are present, we store 0ffh
173
174 call FloppyDrive_GetCountFromBIOS_or_BDA
175
176 push ax
177
178 add al, ch ; Add our drives to existing drive count
179 cmp al, 3 ; For BDA, max out at 4 drives (ours is zero based)
180 jb .MaxBDAFloppiesExceeded
181 mov al, 3
182.MaxBDAFloppiesExceeded:
183 eROR_IM al, 2 ; move to bits 6-7
184 inc ax ; low order bit, indicating floppy drive exists
185
186 mov ah, 3Eh ; AND mask to AH (all bits set except floppy drive count/present)
187 and ah, [es:BDA.wEquipment] ; Load Equipment WORD low byte and mask off drive number and drives present bit
188 or al, ah ; Or in new values
189 mov [es:BDA.wEquipment], al ; and store
190
191 mov al, 1Eh ; BDA pointer to Floppy DPT
192 mov si, AH8h_FloppyDPT
193 call Interrupts_InstallHandlerToVectorInALFromCSSI
194
195 pop ax
196
197 shr ch, 1 ; number of drives, 1 or 2 only, to CF flag (clear=1, set=2)
198 eRCL_IM al, 1 ; starting drive number in upper 7 bits, number of drives in low bit
199.NoFloppies:
200 mov [RAMVARS.xlateVars+XLATEVARS.bFlopCntAndFirst], al
201%endif
202 ret
203
204%ifndef CHECK_FOR_UNUSED_ENTRYPOINTS
205 %if FLG_ROMVARS_SERIAL_SCANDETECT != 8
206 %error "DetectDrives is currently coded to assume that FLG_ROMVARS_SERIAL_SCANDETECT is the same bit as the ALT key code in the BDA. Changes in the code will be needed if these values are no longer the same."
207 %endif
208%endif
209
210
211;--------------------------------------------------------------------
212; StartDetectionWithDriveSelectByteInBHandStringInCX
213; Parameters:
214; BH: Drive Select byte for Drive and Head Register
215; CX: Offset to "Master" or "Slave" string
216; CS:BP: Ptr to IDEVARS for the drive
217; DS: RAMVARS segment
218; ES: Zero (BDA segment)
219; Returns:
220; Nothing
221; Corrupts registers:
222; AX, BL, CX, DX, SI, DI
223;--------------------------------------------------------------------
224StartDetectionWithDriveSelectByteInBHandStringInCX:
225 call DetectPrint_StartDetectWithMasterOrSlaveStringInCXandIdeVarsInCSBP
226
227%ifdef MODULE_HOTKEYS
228 call HotkeyBar_UpdateDuringDriveDetection
229%endif
230 ; Fall to .ReadAtaInfoFromHardDisk
231
232
233;--------------------------------------------------------------------
234; .ReadAtaInfoFromHardDisk
235; Parameters:
236; BH: Drive Select byte for Drive and Head Register
237; DX: Autodetected port (for devices that support autodetection)
238; CS:BP: Ptr to IDEVARS for the drive
239; DS: RAMVARS segment
240; ES: Zero (BDA segment)
241; Returns:
242; CF: Cleared if ATA-information read successfully
243; Set if any error
244; Corrupts registers:
245; AX, BL, CX, DX, SI, DI
246;--------------------------------------------------------------------
247.ReadAtaInfoFromHardDisk:
248 mov si, BOOTVARS.rgbAtaInfo ; ES:SI now points to ATA info location
249 push es
250 push si
251 push dx
252 push bx
253 call Device_IdentifyToBufferInESSIwithDriveSelectByteInBH
254 pop bx
255 pop dx
256 pop si
257 pop es
258 jnc SHORT CreateBiosTablesForHardDisk
259 ; Fall to .ReadAtapiInfoFromDrive
260
261.ReadAtapiInfoFromDrive: ; Not yet implemented
262 ;call ReadAtapiInfoFromDrive ; Assume CD-ROM
263 ;jnc SHORT _CreateBiosTablesForCDROM
264
265 ;jmp short DetectDrives_DriveNotFound
266;;; fall-through instead of previous jmp instruction
267;--------------------------------------------------------------------
268; DetectDrives_DriveNotFound
269; Parameters:
270; Nothing
271; Returns:
272; CF: Set (from DetectPrint_NullTerminatedStringFromCSSIandSetCF)
273; Corrupts registers:
274; AX, SI
275;--------------------------------------------------------------------
276DetectDrives_DriveNotFound:
277 mov si, g_szNotFound
278 jmp DetectPrint_NullTerminatedStringFromCSSIandSetCF
279
280
281;--------------------------------------------------------------------
282; CreateBiosTablesForHardDisk
283; Parameters:
284; BH: Drive Select byte for Drive and Head Register
285; DX: Autodetected port (for devices that support autodetection)
286; CS:BP: Ptr to IDEVARS for the drive
287; ES:SI Ptr to ATA information for the drive
288; DS: RAMVARS segment
289; ES: BDA segment
290; Returns:
291; Nothing
292; Corrupts registers:
293; AX, BX, CX, DX, SI, DI
294;--------------------------------------------------------------------
295CreateBiosTablesForHardDisk:
296%ifndef NO_ATAID_VALIDATION
297 push bx
298 call AtaID_VerifyFromESSI
299 pop bx
300 jnz SHORT DetectDrives_DriveNotFound
301%endif
302 call CreateDPT_FromAtaInformation
303 jc SHORT DetectDrives_DriveNotFound
304 call DriveDetectInfo_CreateForHardDisk
305 jmp SHORT DetectPrint_DriveNameFromDrvDetectInfoInESBX
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