Board.KolibriOS.org

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$Revision: 593 $

;---------------------------------------------------------------------------------------------------
; code determines which mechanism to access PCI bus is available and suported by the bus
;---------------------------------------------------------------------------------------------------

        push  ds
        xor   edi, edi
        mov   ds, di
        mov   dword [BOOT_PCI_DATA], 1            ; default to mechanism 1 and zero other bytes
        mov   dword [BOOT_PCI_DATA+4], edi
        mov   ax, 0xb101
        int   0x1a
        test  ah, ah                            ; apparently command decision has been made to give
        jnz   @f                                ;        some slack to the fact of PCI BIOS absence

        ; bit 1 of AL indicates presence of mechanism 2
        bt    ax, 1                             ; bit_1 -> CF
        adc   byte [BOOT_PCI_DATA], 0             ; 1 += CF
        mov   [BOOT_PCI_DATA+1], cl               ; numerically highest PCI bus in system
        mov   [BOOT_PCI_DATA+2], bx               ; bl-minor version, bh-major version
        mov   [BOOT_PCI_DATA+4], edi              ; address of protected mode entry

        ; by the way mechanism #1 is good and #2 is bad because legacy
@@:
        pop   ds

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$Revision: 750 $


align 4
pci_api:

        cmp   [pci_access_enabled], 1
        jne   .no_pci_access_for_applications

        cmp   al, 10
        ja    .no_pci_access_for_applications
        cmp   al, 7
        ja    pci_write_reg
        jz    .no_pci_access_for_applications
        cmp   al, 3
        ja    pci_read_reg
        jz    .no_pci_access_for_applications
        test  al, al
        jz    .fn_0_version

        neg    eax
        movzx  eax, byte [BOOT_VAR+BOOT_PCI_DATA+2+eax]        ; get either highest bus # or access method
        jmp    .exit

.fn_0_version:
        movzx  eax, word [BOOT_VAR+BOOT_PCI_DATA+2]            ; PCI function 0: get pci version (AH.AL)
.exit:
ret
.no_pci_access_for_applications:
        mov   eax, -1
        jmp   .exit           

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f62call:
        dd      pci_fn_0
        dd      pci_fn_1
        dd      pci_fn_2
        dd      pci_service_not_supported       ;3
        dd      pci_read_reg            ;4 byte
        dd      pci_read_reg            ;5 word
        dd      pci_read_reg            ;6 dword
        dd      pci_service_not_supported   ;7
        dd      pci_write_reg           ;8 byte
        dd      pci_write_reg           ;9 word
        dd      pci_write_reg           ;10 dword
if defined mmio_pci_addr
        dd      pci_mmio_init           ;11
        dd      pci_mmio_map            ;12
        dd      pci_mmio_unmap          ;13
end if