PCI32.INC

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;                                                           ;;
;;  PCI32.INC                                                ;;
;;                                                           ;;
;;  32 bit PCI driver code                                   ;;
;;                                                           ;;
;;  Version 0.2  December 21st, 2002                         ;;
;;                                                           ;;
;;  Author: Victor Prodan, victorprodan@yahoo.com            ;;
;;    Credits:                                               ;;
;;          Ralf Brown                                       ;;
;;          Mike Hibbett, mikeh@oceanfree.net                ;;
;;                                                           ;;
;;  See file COPYING for details                             ;;
;;                                                           ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


;***************************************************************************
;   Function
;      pci_api:
;
;   Description
;       entry point for system PCI calls
;***************************************************************************

align 4

pci_api:

	cmp  [pci_access_enabled],1
	jne  no_pci_access_for_applications

	or al,al
	jnz pci_fn_1
	; PCI function 0: get pci version (AH.AL)
	movzx eax,word [0x2F0000+0x9022]
	ret

pci_fn_1:
	cmp al,1
	jnz pci_fn_2

	; PCI function 1: get last bus in AL
	mov al,[0x2F0000+0x9021]
	ret

pci_fn_2:
	cmp al,2
	jne pci_fn_3
	; PCI function 2: get pci access mechanism
	mov al,[0x2F0000+0x9020]
	ret
pci_fn_3:

	cmp al,4
	jz pci_read_reg   ;byte
	cmp al,5        
	jz pci_read_reg   ;word
	cmp al,6        
	jz pci_read_reg   ;dword

	cmp al,8          
	jz pci_write_reg  ;byte
	cmp al,9
	jz pci_write_reg  ;word
	cmp al,10
	jz pci_write_reg  ;dword

      no_pci_access_for_applications:

	mov eax,-1

	ret

;***************************************************************************
;   Function
;      pci_make_config_cmd
;
;   Description
;       creates a command dword  for use with the PCI bus
;       bus # in ah
;       device+func in bh (dddddfff)
;       register in bl
;
;      command dword returned in eax ( 10000000 bbbbbbbb dddddfff rrrrrr00 )
;***************************************************************************

align 4

pci_make_config_cmd:
    shl     eax,8          ; move bus to bits 16-23
    mov     ax,bx          ; combine all
    and     eax,0xffffff   
    or      eax,0x80000000
    ret
   
;***************************************************************************
;   Function
;      pci_read_reg:
;
;   Description
;       read a register from the PCI config space into EAX/AX/AL
;       IN: ah=bus,device+func=bh,register address=bl
;           number of bytes to read (1,2,4) coded into AL, bits 0-1
;***************************************************************************

align 4

pci_read_reg:
	cmp     byte [0x2F0000+0x9020],2 ;what mechanism will we use?
	je      pci_read_reg_2

		; mechanism 1
	push    esi   ; save register size into ESI
	mov     esi,eax
	and     esi,3

	call    pci_make_config_cmd
	mov     ebx,eax
		; get current state
	mov     dx,0xcf8
	in      eax, dx
	push    eax
		; set up addressing to config data
	mov     eax,ebx
	and     al,0xfc ; make address dword-aligned
	out     dx,eax
		; get requested DWORD of config data
	mov     dl,0xfc
	and     bl,3
	or      dl,bl    ; add to port address first 2 bits of register address

	or      esi,esi
	jz      pci_read_byte1
	cmp     esi,1
	jz      pci_read_word1
	cmp     esi,2
	jz      pci_read_dword1
	jmp     pci_fin_read1

pci_read_byte1:
	in      al,dx
	jmp pci_fin_read1
pci_read_word1:
	in      ax,dx
	jmp pci_fin_read1
pci_read_dword1:
	in      eax,dx
	jmp     pci_fin_read1
pci_fin_read1:
		; restore configuration control
	xchg    eax,[esp]
	mov     dx,0xcf8
	out     dx,eax

	pop     eax
	pop     esi
	ret
pci_read_reg_2:

	test    bh,128  ;mech#2 only supports 16 devices per bus
	jnz     pci_read_reg_err

	push esi   ; save register size into ESI
	mov esi,eax
	and esi,3

	push    eax
		;store current state of config space
	mov     dx,0xcf8
	in      al,dx
	mov     ah,al
	mov     dl,0xfa
	in      al,dx

	xchg    eax,[esp]
		; out 0xcfa,bus
	mov     al,ah
	out     dx,al
		; out 0xcf8,0x80
	mov     dl,0xf8
	mov     al,0x80
	out     dx,al
		; compute addr
	shr     bh,3 ; func is ignored in mechanism 2
	or      bh,0xc0
	mov     dx,bx

	or      esi,esi
	jz      pci_read_byte2
	cmp     esi,1
	jz      pci_read_word2
	cmp     esi,2
	jz      pci_read_dword2
	jmp     pci_fin_read2

pci_read_byte2:
	in      al,dx
	jmp pci_fin_read2
pci_read_word2:
	in      ax,dx
	jmp pci_fin_read2
pci_read_dword2:
	in      eax,dx
;       jmp pci_fin_read2
pci_fin_read2:
	
		; restore configuration space
	xchg    eax,[esp]
	mov     dx,0xcfa
	out     dx,al
	mov     dl,0xf8
	mov     al,ah
	out     dx,al

	pop     eax
	pop     esi
	ret

pci_read_reg_err:
	xor     eax,eax
	dec     eax
	ret


;***************************************************************************
;   Function
;      pci_write_reg:
;
;   Description
;       write a register from ECX/CX/CL into the PCI config space
;       IN: ah=bus,device+func=bh,register address (dword aligned)=bl, 
;           value to write in ecx
;           number of bytes to write (1,2,4) coded into AL, bits 0-1
;***************************************************************************

align 4

pci_write_reg:
	cmp byte [0x2F0000+0x9020],2 ;what mechanism will we use?
	je pci_write_reg_2

		; mechanism 1
	push    esi   ; save register size into ESI
	mov     esi,eax
	and     esi,3

	call    pci_make_config_cmd
	mov     ebx,eax
		; get current state into ecx
	mov     dx,0xcf8
	in      eax, dx
	push    eax
		; set up addressing to config data
	mov     eax,ebx
	and     al,0xfc ; make address dword-aligned
	out     dx,eax
		; write DWORD of config data
	mov     dl,0xfc
	and     bl,3
	or      dl,bl
	mov     eax,ecx

	or      esi,esi
	jz      pci_write_byte1
	cmp     esi,1
	jz      pci_write_word1
	cmp     esi,2
	jz      pci_write_dword1
	jmp     pci_fin_write1

pci_write_byte1:
	out     dx,al
	jmp pci_fin_write1
pci_write_word1:
	out     dx,ax
	jmp pci_fin_write1
pci_write_dword1:
	out     dx,eax
	jmp     pci_fin_write1
pci_fin_write1:

		; restore configuration control
	pop     eax
	mov     dl,0xf8
	out     dx,eax
	
	xor     eax,eax
	pop     esi

	ret
pci_write_reg_2:

	test    bh,128  ;mech#2 only supports 16 devices per bus
	jnz     pci_write_reg_err


	push esi   ; save register size into ESI
	mov esi,eax
	and esi,3

	push    eax
		;store current state of config space
	mov     dx,0xcf8
	in      al,dx
	mov     ah,al
	mov     dl,0xfa
	in      al,dx
	xchg    eax,[esp]
		; out 0xcfa,bus
	mov     al,ah
	out     dx,al
		; out 0xcf8,0x80
	mov     dl,0xf8
	mov     al,0x80
	out     dx,al
		; compute addr
	shr     bh,3 ; func is ignored in mechanism 2
	or      bh,0xc0
	mov     dx,bx
		; write register
	mov     eax,ecx  

	or      esi,esi
	jz      pci_write_byte2
	cmp     esi,1
	jz      pci_write_word2
	cmp     esi,2
	jz      pci_write_dword2
	jmp     pci_fin_write2

pci_write_byte2:
	out     dx,al
	jmp pci_fin_write2
pci_write_word2:
	out     dx,ax
	jmp pci_fin_write2
pci_write_dword2:
	out     dx,eax
	jmp     pci_fin_write2
pci_fin_write2:
		; restore configuration space
	pop     eax
	mov     dx,0xcfa
	out     dx,al
	mov     dl,0xf8
	mov     al,ah
	out     dx,al

	xor     eax,eax 
	pop     esi
	ret

pci_write_reg_err:
	xor     eax,eax
	dec     eax
	ret