title "PCI bus Support Assembley Code" ;++ ; ; Copyright (c) 1989 Microsoft Corporation ; ; Module Name: ; ; hwpcia.asm ; ; Abstract: ; ; Calls the PCI rom function to determine what type of PCI ; support is prsent, if any. ; ; Base code provided by Intel ; ; Author: ; ;-- .386p .xlist include hwpci.inc .list if DBG extrn _BlPrint:PROC endif _DATA SEGMENT PARA USE16 PUBLIC 'DATA' if DBG cr equ 11 PciBIOSSig db 'PCI: Scanning for "PCI "', cr, 0 PciBIOSSigNotFound db 'PCI: BIOS "PCI " not found', cr, 0 PciInt db 'PCI: Calling PCI_BIOS_PRESENT', cr, 0 PciIntFailed db 'PCI: PCI_BIOS_PRESENT returned carry', cr, 0 PciIntAhFailed db 'PCI: PCI_BIOS_PRESENT returned bad AH value', cr, 0 PciIDFailed db 'PCI: PCI_BIOS_PRESENT invalid PCI id', cr, 0 PciInt10IdFailed db 'PCI: PCI10_BIOS_PRESENT invalid PCI id', cr, 0 PciFound db 'PCI BUS FOUND', cr, 0 endif _DATA ends _TEXT SEGMENT PARA USE16 PUBLIC 'CODE' ASSUME CS: _TEXT ;++ ; ; BOOLEAN ; HwGetPciSystemData ( ; PPCI_SYSTEM_DATA PciSystemData ; ) ; ; Routine Description: ; ; This function retrieves the PCI System Data ; ; Arguments: ; ; PciSystemData - Supplies a pointer to the structure which will ; receive the PCI System Data. ; ; Return Value: ; ; True - PCI System Detected and System Data valid ; False - PCI System Not Detected ; ;-- SystemInfoPointer equ [bp + 4] BiosDateFound equ [bp + 6] public _HwGetPciSystemData _HwGetPciSystemData proc push bp ; The following INT 15H destroies mov bp, sp ; ALL the general registers. push si push di push bx ; ; Set for no PCI buses present ; mov bx, SystemInfoPointer mov byte ptr [bx].NoBuses, 0 ; ; Is the BIOS date >= 11/01/92? If so, make the int-1a call ; push ds cmp byte ptr [BiosDateFound], 0 jnz gpci00 ; ; A valid BIOS date was not found, check for "PCI " in bios code. ; if DBG push offset PciBIOSSig call _BlPrint add sp, 2 endif mov bx, 0f000h mov ds, bx mov bx, 0fffch spci05: cmp dword ptr ds:[bx], ' ICP' ; 'PCI ' found at this addr? je short gpci00 ; found dec bx ; next location jnz short spci05 ; loop jmp spci_notfound ; wrapped, all done - not found gpci00: pop ds if DBG push offset PciInt call _BlPrint add sp, 2 endif ; ; Check for a PCI system. Issue the PCI Present request. ; mov ax, PCI_BIOS_PRESENT ; Real Mode Presence Request int PCI_INTERFACE_INT ; Just Do It! jc gpci10 ; Carry Set => No PCI cmp ah, 0 ; If PCI Present AH == 0 jne gpci12 ; AH != 0 => No PCI cmp edx, " ICP" ; "PCI" Backwards (with a trailing space) jne gpci14 ; PCI Signature in EDX => PCI Exists ; ; Found PCI BIOS Version > 1.0 ; ; The only thing left to do is squirrel the data away for the caller ; mov dx, bx ; Save revision level mov bx, SystemInfoPointer ; Get caller's Pointer mov byte ptr [bx].MajorRevision, dh mov byte ptr [bx].MinorRevision, dl inc cl ; NoBuses = LastBus+1 if 0 ; ; Some PIC BIOS returns very large number of NoBuses. As a work- ; around we mask the value to 16, unless the BIOS also return CH as ; neg cl then we believe it. ; cmp cl, 16 jbe short @f neg ch inc ch cmp cl, ch je short @f mov cl, 16 @@: endif mov byte ptr [bx].NoBuses, cl mov byte ptr [bx].HwMechanism, al jmp Done ; We're done if DBG gpci10: mov ax, offset PciIntFailed jmp short gpci_oldbios gpci12: mov ax, offset PciIntAhFailed jmp short gpci_oldbios gpci14: mov ax, offset PciIDFailed gpci_oldbios: push ax call _BlPrint add sp, 2 else gpci10: gpci12: gpci14: endif ; ; Look for BIOS Version 1.0, This has a different function # ; mov ax, PCI10_BIOS_PRESENT ; Real Mode Presence Request int PCI_INTERFACE_INT ; Just Do It! ; Version 1.0 has "PCI " in dx and cx, the Version number in ax, and the ; carry flag cleared. These are all the indications available. ; cmp dx, "CP" ; "PC" Backwards jne gpci50 ; PCI Signature not in DX & CX => No PCI cmp cx, " I" ; "I " Backwards jne gpci50 ; PCI Signature not in EDX => No PCI ; ; Found PCI BIOS Version 1.0 ; ; The only thing left to do is squirrel the data away for the caller ; mov bx, SystemInfoPointer ; Get caller's Pointer mov byte ptr [bx].MajorRevision, ah mov byte ptr [bx].MinorRevision, al ; ; The Version 1.0 BIOS is only on early HW that had couldn't support ; Multi Function devices or multiple bus's. So without reading any ; device data, mark it as such. ; mov byte ptr [bx].HwMechanism, 2 mov byte ptr [bx].NoBuses, 1 jmp Done spci_notfound: pop ds ; restore ds if DBG push offset PciBIOSSigNotFound call _BlPrint add sp, 2 endif jmp gpci_exit if DBG gpci50: push offset PciInt10IdFailed jmp Done10 Done: push offset PciFound Done10: call _BlPrint add sp, 2 else ; non-debug no prints gpci50: Done: endif gpci_exit: pop bx pop di pop si pop bp ret _HwGetPciSystemData endp RouteBuffer equ [bp + 4] ExclusiveIRQs equ [bp + 8] public _HwGetPciIrqRoutingOptions _HwGetPciIrqRoutingOptions proc push bp mov bp, sp ; Create 'C' stack frame. push ebx push edi push esi ; Save registers used. push es push ds xor edi, edi les di, RouteBuffer mov bx, 0f000h mov ds, bx xor ebx, ebx mov ax, 0B10Eh int PCI_INTERFACE_INT pop ds pop es mov di, ExclusiveIRQs mov [di], bx mov al, ah pop esi ; Restore registers. pop edi pop ebx pop bp ret _HwGetPciIrqRoutingOptions endp _TEXT ends end