Nightloader/i386/loader/src-asm/drivers/pci/enumerate.asm

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NASM
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; Arguments:
; ah Bus Number (0 .. 255)
; al Device Number (0 .. 31)
;
; Returns:
; - true/false (eax)
pci_device_exists:
push dword esi
sub esp, 8
mov esi, esp
mov [esi], edx
mov [esi + 4], eax
.make_address:
xor eax, eax
; Enable Bit
or al, 1
; Make space for 8 Reserved Bits and 8 Bytes of bus number.
shl eax, 15
; Bus Number
mov al, [esi + 5]
; Device Number
; Make space for device number
shl eax, 5
mov dl, [esi + 4]
and dl, 0x1f
or al, dl
shl eax, 11
.input_output:
mov dx, PCI_CONFIG_ADDRESS_PORT
out dx, eax
mov dx, PCI_CONFIG_DATA_PORT
in eax, dx
cmp ax, 0xffff
jne .device_found
.not_a_device:
mov edx, [esi]
add esp, 8
pop dword esi
xor eax, eax
ret
.device_found:
mov edx, [esi]
add esp, 8
pop dword esi
mov eax, 1
ret
; Arguments:
; [FURTHEST FROM EBP]
; 3. U16 PCI Device Class & Subclass
; (Higher byte: Class, lower byte: Subclass)
; 2. U16 PCI Device Address
; (Higher byte: Bus Address,
; lower byte: Device Address)
; 1. Ptr32 Pointer to PCI driver area of 65536 bytes
; [NEAREST TO EBP]
pci_append_device:
push dword esi
sub esp, 64
mov esi, esp
mov [esi + (64 - 4)], eax
mov [esi + (64 - 8)], ebx
mov [esi + (64 - 12)], ecx
mov [esi + (64 - 20)], edi
.get_device_count:
mov ebx, [ebp - 4]
xor ecx, ecx
mov cx, [ebx + PCI_DEVICE_COUNT_OFFSET]
mov [esi + 4], cx
.calculate_device_offset:
; Every device slot has 16 bytes, multiply index with 16
shl ecx, 4
; Point into driver device area (add device area start on top)
mov ebx, [ebp - 4]
add ebx, PCI_DEVICE_AREA_OFFSET
add ebx, ecx
.set_device:
mov cx, [ebp - 6]
mov [ebx], cx
mov cx, [ebp - 8]
mov [ebx + 2], cx
.increment_device_count:
mov ebx, [ebp - 4]
inc word [ebx + PCI_DEVICE_COUNT_OFFSET]
.epilog:
mov eax, [esi + (64 - 4)]
mov ebx, [esi + (64 - 8)]
mov ecx, [esi + (64 - 12)]
mov edi, [esi + (64 - 20)]
add esp, 64
pop dword esi
ret
; Arguments:
; [FURTHER FROM EBP]
; 2. U16 Device Number
; 1. U16 Bus Number
; [NEAREST TO EBP]
;
; Returns:
; ax PCI Device Class & Subclass
; (Higher byte: Class, lower byte: Subclass)
pci_get_device_class_at_address:
push dword esi
sub esp, 64
mov esi, esp
mov [esi + (64 - 8)], ebx
mov [esi + (64 - 12)], ecx
mov [esi + (64 - 16)], edx
mov [esi + (64 - 20)], edi
.create_address:
xor eax, eax
; Enable Bit
or al, 1
; Make space for 8 Reserved Bits and 8 Bytes of bus number.
shl eax, 15
; Bus Number
mov al, [ebp - 2]
; Device Number
; Make space for device number
shl eax, 5
mov dl, [ebp - 4]
and dl, 0x1f
or al, dl
shl eax, 11
; Include the register offset of the configuration space
; register which contains the class and subclass
or eax, 8
.input_output:
mov dx, PCI_CONFIG_ADDRESS_PORT
out dx, eax
mov dx, PCI_CONFIG_DATA_PORT
in eax, dx
; Remove the parts of the register which aren't part of the
; PCI class- and subclass-code
shr eax, 16
.epilog:
mov ebx, [esi + (64 - 8)]
mov ecx, [esi + (64 - 12)]
mov edx, [esi + (64 - 16)]
mov edi, [esi + (64 - 20)]
add esp, 64
pop dword esi
ret
; Arguments:
; [FURTHER FROM EBP]
; 2. U32 Bus Number (0 .. 255)
; 1. Ptr32 Pointer to PCI driver area of 65536 bytes
; [NEAREST TO EBP]
;
; Returns:
; - Number of devics on the bus (eax)
pci_enumerate_bus:
push dword esi
sub esp, 64
mov esi, esp
mov [esi + (64 - 8)], ebx
mov [esi + (64 - 12)], ecx
mov [esi + (64 - 20)], edi
; [esi]: Device-in-bus Index
; [esi + 4]: Number of existing devices
; [esi + 8]: Bus number
; [esi + 12]:
mov [esi], dword 0
mov [esi + 4], dword 0
mov eax, [ebp - 8]
mov [esi + 8], eax
mov eax, [ebp - 4]
mov [esi + 12], eax
.initialize_device_loop:
.device_loop:
cmp [esi], dword 32
jae .epilog
.test_whether_device_exists:
mov ah, [esi + 8] ; Bus Number
mov al, [esi] ; Device Number
mov [esi + 16], ax
push ebp
mov ebp, esp
call pci_device_exists
mov esp, ebp
pop ebp
cmp ax, 0
je .no_device
.append_device:
mov al, [esi + 8]
mov ah, [esi]
; Device Number in DX
xor dx, dx
mov dl, ah
xor ah, ah
push ebp
mov ebp, esp
push ax
push dx
call pci_get_device_class_at_address
mov esp, ebp
pop ebp
mov cx, ax
mov ax, [esi + 16]
push ebp
mov ebp, esp
push dword [esi + 12]
push ax
push cx
call pci_append_device
mov esp, ebp
pop ebp
mov ebx, [ebp - 4]
.no_device:
inc dword [esi]
jmp .device_loop
.epilog:
mov ebx, [esi + (64 - 8)]
mov ecx, [esi + (64 - 12)]
mov edi, [esi + (64 - 20)]
mov eax, [esi + 4]
add esp, 64
pop dword esi
ret
; Arguments:
; [FURTHEST FROM EBP]
; 2. U32 Maximum number of devices to enumerate
; (0 to eliminate limit)
; 1. Ptr32 Pointer to PCI driver area of 65536 bytes
; [NEAREST TO EBP]
; Returns:
; eax: Number of devices read
pci_enumerate:
push dword esi
sub esp, 64
mov esi, esp
mov [esi + (64 - 4)], eax
mov [esi + (64 - 8)], ebx
mov [esi + (64 - 12)], ecx
mov [esi + (64 - 16)], edx
mov [esi + (64 - 20)], edi
; [esi]: Number of devices found
; ecx: Bus Index
mov edx, [ebp - 4]
mov [esi + 4], edx
; Set the device count to 0 explicitly, just for safety.
mov ebx, [ebp - 4]
add ebx, PCI_DEVICE_COUNT_OFFSET
mov [ebx], word 0
.bus_loop:
xor ecx, ecx
mov [esi], dword 0
.bus_loop_body:
; Test whether the device count is unlimited,
; ignore the device count check if it is.
cmp [ebp - 8], dword 0
je .call_bus_enumerator
mov edx, [esi]
cmp edx, [ebp - 8]
jae .epilog
.call_bus_enumerator:
push ebp
mov ebp, esp
push dword [esi + 4]
push ecx
call pci_enumerate_bus
mov esp, ebp
pop ebp
; Add the number of devices found on the bus
; to the number of devices found in total.
add [esi], eax
mov ebx, [esi + 4]
add [ebx + PCI_DEVICE_COUNT_OFFSET], ax
; Go to the next bus (if there is one)
inc ecx
cmp ecx, 256
jb .bus_loop_body
.epilog:
mov ebx, [esi + (64 - 8)]
mov ecx, [esi + (64 - 12)]
mov edx, [esi + (64 - 16)]
mov edi, [esi + (64 - 20)]
mov eax, [esi]
add esp, 64
pop dword esi
ret