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	cmp al,11	    ; <<< user-level MMIO functions <<< NEW!

	jz pci_mmio_init

	cmp al,12

	jz pci_mmio_map

	cmp al,13

	jz pci_mmio_unmap

;***************************************************************************

;   Function

;      pci_mmio_init ; NEW!

;

;   Description

;       IN:  bx = device's PCI bus address (bbbbbbbbdddddfff)

;       returns ax = user heap space available (bytes)

;   Error codes

;       eax = -1 : PCI user access blocked,

;       eax = -2 : device not registered for uMMIO service

;       eax = -3 : user heap initialization failure

;***************************************************************************

align 4

pci_mmio_init:

    cmp     bx, word [mmio_pci_addr]	; must be set in kernel/data32.inc

    jz	    @f

    mov     eax,-2

    ret

@@:

    call    init_heap	   ; (if not initialized yet)

    or	    eax,eax

    jz	    @f

    ret

@@:

    mov     eax,-3

    ret

;***************************************************************************

;   Function

;      pci_mmio_map ; NEW!

;

;   Description

;       maps a block of PCI memory to user-accessible linear address

;

;       WARNING! This VERY EXPERIMENTAL service is for one chosen PCI device only!

;       The target device address should be set in kernel var mmio_pci_addr

;

;       IN:  ah = BAR#;

;       IN: ebx = block size (bytes);

;       IN: ecx = offset in MMIO block (in 4K-pages, to avoid misaligned pages);

;

;   Returns eax = MMIO block's linear address in the userspace (if no error)

;

;

;   Error codes

;       eax = -1 : user access to PCI blocked,

;       eax = -2 : an invalid BAR register referred

;       eax = -3 : no i/o space on that BAR

;       eax = -4 : a port i/o BAR register referred

;       eax = -5 : dynamic userspace allocation problem

;***************************************************************************

align 4

pci_mmio_map:

    and     edx,0x0ffff

    cmp     ah,6

    jc	    @f

    mov     eax,-2

    ret

@@:

    push    ecx

    add     ebx, 4095

    and     ebx,-4096

    push    ebx

    mov     bl, ah	; bl = BAR# (0..5)

    shl     bl, 1

    shl     bl, 1

    add     bl, 0x10	; bl = BARs offset in PCI config. space

    mov     ax,word [mmio_pci_addr]

    mov     bh, al	; bh = dddddfff

    mov     al, 2	; al : DW to read

    call    pci_read_reg

    or	    eax, eax

    jnz     @f

    mov     eax,-3	; empty I/O space

    jmp     mmio_ret_fail

@@:

    test    eax, 1

    jz	    @f

    mov     eax,-4	; damned ports (not MMIO space)

    jmp     mmio_ret_fail

@@:

    pop     ecx 	; ecx = block size, bytes (expanded to whole page)

    mov     ebx, ecx	; user_alloc destroys eax, ecx, edx, but saves ebx

    push    eax 	; store MMIO physical address + keep 2DWords in the stack

    stdcall user_alloc, ecx

    or	    eax, eax

    jnz     mmio_map_over

    mov     eax,-5	; problem with page allocation

mmio_ret_fail:

    pop     ecx

    pop     edx

    ret

mmio_map_over:

    mov     ecx, ebx	; ecx = size (bytes, expanded to whole page)

    shr     ecx, 12	; ecx = number of pages

    mov     ebx, eax	; ebx = linear address

    pop     eax 	; eax = MMIO start

    pop     edx 	; edx = MMIO shift (pages)

    shl     edx, 12	; edx = MMIO shift (bytes)

    add     eax, edx	; eax = uMMIO physical address

    or	    eax, PG_SHARED

    or	    eax, PG_UW

    or	    eax, PG_NOCACHE

    mov     edi, ebx

    call    commit_pages

    mov     eax, edi

    ret

;***************************************************************************

;   Function

;      pci_mmio_unmap_page ; NEW!

;

;   Description

;       unmaps the linear space previously tied to a PCI memory block

;

;       IN: ebx = linear address of space previously allocated by pci_mmio_map

;       returns eax = 1 if successfully unmapped

;

;   Error codes

;       eax = -1 if no user PCI access allowed,

;       eax =  0 if unmapping failed

;***************************************************************************

align 4

pci_mmio_unmap:

    stdcall user_free, ebx

    ret