; Stub of videodriver for Intel videocards.
; (c) CleverMouse

; When the start procedure gots control,
; it tries to detect preferred resolution,
; sets the detected resolution assuming 32-bpp VESA mode and exits
; (without registering a service).
; Detection can be overloaded with compile-time settings
; use_predefined_mode/predefined_width/predefined_height.

; set predefined resolution here
use_predefined_mode = 0;1
predefined_width = 0;1366
predefined_height = 0;768

; standard driver stuff
format MS COFF

DEBUG = 1

include 'proc32.inc'
include 'imports.inc'

public START
public version

section '.flat' code readable align 16
; the start procedure (see the description above)
START:
; 1. Detect device. Abort if not found.
	push	esi
	call	DetectDevice
	test	esi, esi
	jz	.return0
; 2. Detect optimal mode unless the mode is given explicitly. Abort if failed.
if use_predefined_mode = 0
	call	DetectMode
end if
	cmp	[width], 0
	jz	.return0_cleanup
; 3. Set the detected mode.
	call	SetMode
; 4. Cleanup and return.
.return0_cleanup:
	stdcall	FreeKernelSpace, esi
.return0:
	pop	esi
	xor	eax, eax
	ret	4

; check that there is Intel videocard
; if so, map MMIO registers and set internal variables
; esi points to MMIO block; NULL means no device
DetectDevice:
; 1. Sanity check: check that we are dealing with Intel videocard.
; Integrated video device for Intel is always at PCI:0:2:0.
	xor	esi, esi	; initialize return value to NULL
; 1a. Get PCI VendorID and DeviceID.
	push	esi
	push	10h
	push	esi
	call	PciRead32
; 1b. loword(eax) = ax = VendorID, hiword(eax) = DeviceID.
; Test whether we have Intel chipset.
	cmp	ax, 8086h
	jnz	.return
; 1c. Say hi including DeviceID.
	shr	eax, 10h
	push	edi
	pusha
	mov	edi, pciid_text
	call	WriteWord
	mov	esi, hellomsg
	call	SysMsgBoardStr
	popa
; 1d. Test whether we know this DeviceID.
; If this is the case, remember the position of the device in line of Intel cards;
; this knowledge will be useful later.
; Tested on devices with id: 8086:0046, partially 8086:2A02.
	mov	ecx, pciids_num
	mov	edi, pciids
	repnz	scasw
	pop	edi
	jnz	.return_unknown_pciid
	sub	ecx, pciids_num - 1
	neg	ecx
	mov	[deviceType], ecx
; 1e. Continue saying hi with positive intonation.
	pusha
	mov	esi, knownmsg
	call	SysMsgBoardStr
	popa
; 2. Prepare MMIO region to control the card.
; 2a. Read MMIO physical address from PCI config space.
	push	10h
	push	10h
	push	esi
	call	PciRead32
; 2b. Mask out PCI region type, lower 4 bits.
	and	al, not 0xF
; 2c. Create virtual mapping of the physical memory.
	push	1Bh
	push	100000h
	push	eax
	call	MapIoMem
; 3. Return.
	xchg	esi, eax
.return:
	ret
; 1f. If we do not know DeviceID, continue saying hi with negative intonation.
.return_unknown_pciid:
	pusha
	mov	esi, unknownmsg
	call	SysMsgBoardStr
	popa
	ret

; Convert word in ax to hexadecimal text in edi, advance edi.
WriteWord:
; 1. Convert high byte.
	push	eax
	mov	al, ah
	call	WriteByte
	pop	eax
; 2. Convert low byte.
; Fall through to WriteByte; ret from WriteByte is ret from WriteWord too.

; Convert byte in al to hexadecimal text in edi, advance edi.
WriteByte:
; 1. Convert high nibble.
	push	eax
	shr	al, 4
	call	WriteNibble
	pop	eax
; 2. Convert low nibble.
	and	al, 0xF
; Fall through to WriteNibble; ret from WriteNibble is ret from WriteByte too.

; Convert nibble in al to hexadecimal text in edi, advance edi.
WriteNibble:
; Obvious, isn't it?
	cmp	al, 10
	sbb	al, 69h
	das
	stosb
	ret

if use_predefined_mode = 0
; detect resolution of the flat panel
DetectMode:
	push	esi edi
; 1. Get the location of block of GMBUS* registers.
; Starting with Ironlake, GMBUS* registers were moved.
	add	esi, 5100h
	cmp	[deviceType], ironlake_start
	jb	@f
	add	esi, 0xC0000
@@:
; 2. Initialize GMBUS engine.
	mov	edi, edid
	mov	ecx, 0x10000
@@:
	test	byte [esi+8+1], 80h
	loopnz	@b
	jnz	.fail
	mov	dword [esi], 3
	test	byte [esi+8+1], 4
	jz	.noreset
	call	ResetGMBus
	jnz	.fail
.noreset:
; 3. Send read command.
	and	dword [esi+20h], 0
	mov	dword [esi+4], 4E8000A1h
; 4. Wait for data, writing to the buffer as data arrive.
.getdata:
	mov	ecx, 0x10000
@@:
	test	byte [esi+8+1], 8
	loopz	@b
	test	byte [esi+8+1], 4
	jz	.dataok
	call	ResetGMBus
	jmp	.fail
.dataok:
	mov	eax, [esi+0Ch]
	stosd
	cmp	edi, edid+80h
	jb	.getdata
; 5. Wait for bus idle.
	mov	ecx, 0x10000
@@:
	test	byte [esi+8+1], 2
	loopnz	@b
; 6. We got EDID; dump it if DEBUG.
if DEBUG
	pusha
	xor	ecx, ecx
	mov	esi, edid
	mov	edi, edid_text
.dumploop:
	lodsb
	call	WriteByte
	mov	al, ' '
	stosb
	inc	cl
	test	cl, 15
	jnz	@f
	mov	byte [edi-1], 13
	mov	al, 10
	stosb
@@:
	test	cl, cl
	jns	.dumploop
	mov	esi, edidmsg
	call	SysMsgBoardStr
	popa
end if
; 7. Test whether EDID is good.
; 7a. Signature: 00 FF FF FF FF FF FF 00.
	mov	esi, edid
	cmp	dword [esi], 0xFFFFFF00
	jnz	.fail
	cmp	dword [esi+4], 0x00FFFFFF
	jnz	.fail
; 7b. Checksum must be zero.
	xor	edx, edx
	mov	ecx, 80h
@@:
	lodsb
	add	dl, al
	loop	@b
	jnz	.fail
; 8. Get width and height from EDID.
	xor	eax, eax
	mov	ah, [esi-80h+3Ah]
	shr	ah, 4
	mov	al, [esi-80h+38h]
	mov	[width], eax
	mov	ah, [esi-80h+3Dh]
	shr	ah, 4
	mov	al, [esi-80h+3Bh]
	mov	[height], eax
; 9. Return.
.fail:
	pop	edi esi
	ret

; reset bus, clear all errors
ResetGMBus:
; look into the PRM
	mov	dword [esi+4], 80000000h
	mov	dword [esi+4], 0
	mov	ecx, 0x10000
@@:
	test	byte [esi+8+1], 2
	loopnz	@b
	ret
end if

; set resolution [width]*[height]
SetMode:
; 1. Program the registers of videocard.
; look into the PRM
	cli
	or	byte [esi+7000Ah], 0Ch	; PIPEACONF: disable Display+Cursor Planes
	or	byte [esi+7100Ah], 0Ch	; PIPEBCONF: disable Display+Cursor Planes
	and	byte [esi+7000Bh], not 80h	; PIPEACONF: disable pipe
	and	byte [esi+7100Bh], not 80h	; PIPEBCONF: disable pipe
;	or	byte [esi+71403h], 80h	; VGACNTRL: VGA Display Disable
	mov	edx, 10000h
@@:
	mov	ecx, 1000h
	loop	$
	test	byte [esi+7000Bh], 40h	; PIPEACONF: wait until pipe disabled
	jz	@f
	dec	edx
	jnz	@b
.not_disabled:
	sti
	jmp	.return
@@:
	test	byte [esi+7100Bh], 40h	; PIPEBCONF: wait until pipe disabled
	jz	@f
	mov	ecx, 1000h
	loop	$
	dec	edx
	jnz	@b
	jmp	.not_disabled
@@:
	lea	eax, [esi+61183h]
	cmp	[deviceType], ironlake_start
	jb	@f
	add	eax, 0xE0000 - 0x60000
@@:
	lea	edx, [esi+60000h]
	test	byte [eax], 40h
	jz	@f
	add	edx, 1000h
@@:
	mov	eax, [width]
	dec	eax
	shl	eax, 16
	mov	ax, word [height]
	dec	eax
	mov	dword [edx+1Ch], eax	; PIPEASRC: set source image size
	ror	eax, 16
	mov	dword [edx+10190h], eax	; for old cards
	mov	ecx, [width]
	add	ecx, 15
	and	ecx, not 15
	shl	ecx, 2
	mov	dword [edx+10188h], ecx	; DSPASTRIDE: set scanline length
	and	byte [esi+61233h], not 80h	; PFIT_CONTROL: disable panel fitting 
	or	byte [edx+10183h], 80h		; DSPACNTR: enable Display Plane A
	or	byte [edx+1000Bh], 80h		; PIPEACONF: enable pipe
	and	byte [edx+1000Ah], not 0Ch	; PIPEACONF: enable Display+Cursor Planes
	sti
; 2. Notify the kernel that resolution has changed.
	call	GetDisplay
	mov	edx, [width]
	mov	dword [eax+8], edx
	mov	edx, [height]
	mov	dword [eax+0Ch], edx
	mov	[eax+18h], ecx
	mov	eax, [width]
	dec	eax
	dec	edx
	call	SetScreen
.return:
	ret

align 4
hellomsg	db	'Intel videocard detected, PciId=8086:'
pciid_text	db	'0000'
		db	', which is ', 0
knownmsg	db	'known',13,10,0
unknownmsg	db	'unknown',13,10,0

if DEBUG
edidmsg		db	'EDID successfully read:',13,10
edid_text	rb	8*(16*3+1)
		db	0
end if

version:
	dd	0x50005

width	dd	predefined_width
height	dd	predefined_height

pciids:
	dw	0x2582	; i915g
	dw	0x258a	; i915g
	dw	0x2592	; i915gm
	dw	0x2772	; i945g
	dw	0x27a2	; i945gm
	dw	0x27ae	; i945gm
	dw	0x2972	; i965g
	dw	0x2982	; i965g
	dw	0x2992	; i965g
	dw	0x29a2	; i965g
	dw	0x29b2	; g33
	dw	0x29c2	; g33
	dw	0x29d2	; g33
	dw	0x2a02	; i965gm
	dw	0x2a12	; i965gm
	dw	0x2a42	; gm45
	dw	0x2e02	; g45
	dw	0x2e12	; g45
	dw	0x2e22	; g45
	dw	0x2e32	; g45
	dw	0x2e42	; g45
	dw	0x2e92	; g45
	dw	0xa001	; pineview
	dw	0xa011	; pineview
ironlake_start = ($ - pciids) / 2
	dw	0x0042	; ironlake_d
	dw	0x0046	; ironlake_m
	dw	0x0102	; sandybridge_d
	dw	0x0112	; sandybridge_d
	dw	0x0122	; sandybridge_d
	dw	0x0106	; sandybridge_m
	dw	0x0116	; sandybridge_m
	dw	0x0126	; sandybridge_m
	dw	0x010A	; sandybridge_d
pciids_num = ($ - pciids) / 2

align 4
deviceType	dd	?
edid	rb	0x80