;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;                                                              ;;
;; Copyright (C) KolibriOS team 2010-2024. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License    ;;
;;                                                              ;;
;;                                                              ;;
;;  PCIe.INC                                                    ;;
;;                                                              ;;
;;  Extended PCI express services                               ;;
;;                                                              ;;
;;                  art_zh  <artem@jerdev.co.uk>                ;;
;;                                                              ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


;***************************************************************************
;   Function
;      pci_ext_config:
;
;   Description
;       PCIe extended (memory-mapped) config space detection
;
;   WARNINGs:
;       1) Very Experimental!
;       2) direct HT-detection (no ACPI or BIOS service used)
;       3) Only AMD/HT processors currently supported
;
;***************************************************************************

PCIe_CONFIG_SPACE       =       0xF0000000      ; to be moved to const.inc
mmio_pcie_cfg_addr      dd      0x0             ; intel pcie space may be defined here
mmio_pcie_cfg_lim       dd      0x0             ; upper pcie space address


align 4

pci_ext_config:

        mov     ebx, [mmio_pcie_cfg_addr]
        or      ebx, ebx
        jz      @f
        or      ebx, 0x7FFFFFFF         ; required by PCI-SIG standards
        jnz     .pcie_failed
        add     ebx, 0x0FFFFC
        cmp     ebx, [mmio_pcie_cfg_lim]; is the space limit correct?
        ja      .pcie_failed
        jmp     .pcie_cfg_mapped
@@:
        mov     ebx, [cpu_vendor]
        cmp     ebx, dword [AMD_str]
        jne     .pcie_failed
        mov     bx, 0xC184              ; dev = 24, fn = 01, reg = 84h

.check_HT_mmio:
        mov     cx, bx
        mov     ax, 0x0002              ; bus = 0, 1dword to read
        call    pci_read_reg
        mov     bx, cx
        sub     bl, 4
        and     al, 0x80                ; check the NP bit
        jz      .no_pcie_cfg
        shl     eax, 8                  ; bus:[27..20], dev:[19:15]
        or      eax, 0x00007FFC         ; fun:[14..12], reg:[11:2]
        mov     [mmio_pcie_cfg_lim], eax
        mov     cl, bl
        mov     ax, 0x0002              ; bus = 0, 1dword to read
        call    pci_read_reg
        mov     bx, cx
        test    al, 0x03                ; MMIO Base RW enabled?
        jz      .no_pcie_cfg
        test    al, 0x0C                ; MMIO Base locked?
        jnz     .no_pcie_cfg
        xor     al, al
        shl     eax, 8
        test    eax, 0x000F0000         ; MMIO Base must be bus0-aligned
        jnz     .no_pcie_cfg
        mov     [mmio_pcie_cfg_addr], eax
        add     eax, 0x000FFFFC
        sub     eax, [mmio_pcie_cfg_lim]; MMIO must cover at least one bus
        ja      .no_pcie_cfg

;       -- it looks like a true PCIe config space;
        mov     eax, [mmio_pcie_cfg_addr]       ; physical address
        or      eax, (PG_SHARED + PG_LARGE + PG_USER)
        mov     ebx, PCIe_CONFIG_SPACE          ; linear address
        mov     ecx, ebx
        shr     ebx, 20
        add     ebx, sys_pgdir                  ; PgDir entry @
@@:
        mov     dword[ebx], eax                 ; map 4 buses
        invlpg  [ecx]
        cmp     bl, 4
        jz      .pcie_cfg_mapped                ; fix it later
        add     bl, 4                           ; next PgDir entry
        add     eax, 0x400000                   ; eax += 4M
        add     ecx, 0x400000
        jmp     @b

.pcie_cfg_mapped:

;       -- glad to have the extended PCIe config field found
;       mov     esi, boot_pcie_ok
;       call    boot_log
        ret     ; <<<<<<<<<<< OK >>>>>>>>>>>

.no_pcie_cfg:

        xor     eax, eax
        mov     [mmio_pcie_cfg_addr], eax
        mov     [mmio_pcie_cfg_lim], eax
        add     bl, 12
        cmp     bl, 0xC0                ; MMIO regs lay below this offset
        jb      .check_HT_mmio
.pcie_failed:
;       mov     esi, boot_pcie_fail
;       call    boot_log
        ret     ; <<<<<<<<< FAILURE >>>>>>>>>