libgfxinit/common/hw-gfx-edid.adb

181 lines
6.6 KiB
Ada

--
-- Copyright (C) 2016 secunet Security Networks AG
--
-- This program is free software; you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation; version 2 of the License.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
with HW;
with HW.Debug;
with GNAT.Source_Info;
use type HW.Byte;
use type HW.Pos16;
use type HW.Word16;
package body HW.GFX.EDID is
function Checksum_Valid (Raw_EDID : Raw_EDID_Data) return Boolean
with
Pre => True
is
Sum : Byte := 16#00#;
begin
for I in Raw_EDID_Index loop
Sum := Sum + Raw_EDID (I);
end loop;
pragma Debug (Sum /= 16#00#, Debug.Put_Line
(GNAT.Source_Info.Enclosing_Entity & ": EDID checksum invalid!"));
return Sum = 16#00#;
end Checksum_Valid;
function Valid (Raw_EDID : Raw_EDID_Data) return Boolean
is
Header_Valid : Boolean;
begin
Header_Valid :=
Raw_EDID (0) = 16#00# and
Raw_EDID (1) = 16#ff# and
Raw_EDID (2) = 16#ff# and
Raw_EDID (3) = 16#ff# and
Raw_EDID (4) = 16#ff# and
Raw_EDID (5) = 16#ff# and
Raw_EDID (6) = 16#ff# and
Raw_EDID (7) = 16#00#;
pragma Debug (not Header_Valid, Debug.Put_Line
(GNAT.Source_Info.Enclosing_Entity & ": EDID header pattern mismatch!"));
return Header_Valid and then Checksum_Valid (Raw_EDID);
end Valid;
----------------------------------------------------------------------------
REVISION : constant := 19;
INPUT : constant := 20;
INPUT_DIGITAL : constant := 1 * 2 ** 7;
INPUT_DIGITAL_DEPTH_SHIFT : constant := 4;
INPUT_DIGITAL_DEPTH_MASK : constant := 7 * 2 ** 4;
INPUT_DIGITAL_DEPTH_UNDEF : constant := 0 * 2 ** 4;
INPUT_DIGITAL_DEPTH_RESERVED : constant := 7 * 2 ** 4;
----------------------------------------------------------------------------
function Read_LE16
(Raw_EDID : Raw_EDID_Data;
Offset : Raw_EDID_Index)
return Word16
is
begin
return Shift_Left (Word16 (Raw_EDID (Offset + 1)), 8) or
Word16 (Raw_EDID (Offset));
end Read_LE16;
function Has_Preferred_Mode (Raw_EDID : Raw_EDID_Data) return Boolean
is
begin
return
Int64 (Read_LE16 (Raw_EDID, DESCRIPTOR_1)) * 10_000
in Frequency_Type and
( Raw_EDID (DESCRIPTOR_1 + 2) /= 0 or
(Raw_EDID (DESCRIPTOR_1 + 4) and 16#f0#) /= 0) and
( Raw_EDID (DESCRIPTOR_1 + 8) /= 0 or
(Raw_EDID (DESCRIPTOR_1 + 11) and 16#c0#) /= 0) and
( Raw_EDID (DESCRIPTOR_1 + 9) /= 0 or
(Raw_EDID (DESCRIPTOR_1 + 11) and 16#30#) /= 0) and
( Raw_EDID (DESCRIPTOR_1 + 3) /= 0 or
(Raw_EDID (DESCRIPTOR_1 + 4) and 16#0f#) /= 0) and
( Raw_EDID (DESCRIPTOR_1 + 5) /= 0 or
(Raw_EDID (DESCRIPTOR_1 + 7) and 16#f0#) /= 0) and
((Raw_EDID (DESCRIPTOR_1 + 10) and 16#f0#) /= 0 or
(Raw_EDID (DESCRIPTOR_1 + 11) and 16#0c#) /= 0) and
((Raw_EDID (DESCRIPTOR_1 + 10) and 16#0f#) /= 0 or
(Raw_EDID (DESCRIPTOR_1 + 11) and 16#03#) /= 0) and
( Raw_EDID (DESCRIPTOR_1 + 6) /= 0 or
(Raw_EDID (DESCRIPTOR_1 + 7) and 16#0f#) /= 0);
end Has_Preferred_Mode;
function Preferred_Mode (Raw_EDID : Raw_EDID_Data) return Mode_Type
is
Base : constant := DESCRIPTOR_1;
Mode : Mode_Type;
function Read_12
(Lower_8, Upper_4 : Raw_EDID_Index;
Shift : Natural)
return Word16
is
begin
return
Word16 (Raw_EDID (Lower_8)) or
(Shift_Left (Word16 (Raw_EDID (Upper_4)), Shift) and 16#0f00#);
end Read_12;
function Read_10
(Lower_8, Upper_2 : Raw_EDID_Index;
Shift : Natural)
return Word16
is
begin
return
Word16 (Raw_EDID (Lower_8)) or
(Shift_Left (Word16 (Raw_EDID (Upper_2)), Shift) and 16#0300#);
end Read_10;
function Read_6
(Lower_4 : Raw_EDID_Index;
Lower_Shift : Natural;
Upper_2 : Raw_EDID_Index;
Upper_Shift : Natural)
return Word8
is
begin
return
(Shift_Right (Word8 (Raw_EDID (Lower_4)), Lower_Shift) and 16#0f#)
or
(Shift_Left (Word8 (Raw_EDID (Upper_2)), Upper_Shift) and 16#30#);
end Read_6;
begin
Mode := Mode_Type'
(Dotclock => Pos64 (Read_LE16 (Raw_EDID, Base)) * 10_000,
H_Visible => Pos16 (Read_12 (Base + 2, Base + 4, 4)),
H_Sync_Begin => Pos16 (Read_10 (Base + 8, Base + 11, 2)),
H_Sync_End => Pos16 (Read_10 (Base + 9, Base + 11, 4)),
H_Total => Pos16 (Read_12 (Base + 3, Base + 4, 8)),
V_Visible => Pos16 (Read_12 (Base + 5, Base + 7, 4)),
V_Sync_Begin => Pos16 (Read_6 (Base + 10, 4, Base + 11, 2)),
V_Sync_End => Pos16 (Read_6 (Base + 10, 0, Base + 11, 4)),
V_Total => Pos16 (Read_12 (Base + 6, Base + 7, 8)),
H_Sync_Active_High => (Raw_EDID (Base + 17) and 16#02#) /= 0,
V_Sync_Active_High => (Raw_EDID (Base + 17) and 16#04#) /= 0,
BPC =>
(if Raw_EDID (REVISION) < 4 or
(Raw_EDID (INPUT) and INPUT_DIGITAL) = 16#00# or
(Raw_EDID (INPUT) and INPUT_DIGITAL_DEPTH_MASK) = INPUT_DIGITAL_DEPTH_UNDEF or
(Raw_EDID (INPUT) and INPUT_DIGITAL_DEPTH_MASK) = INPUT_DIGITAL_DEPTH_RESERVED
then
0
else
4 + 2 * Pos64 (Shift_Right
(Raw_EDID (INPUT) and INPUT_DIGITAL_DEPTH_MASK,
INPUT_DIGITAL_DEPTH_SHIFT))));
-- Calculate absolute values from EDID relative values.
Mode.H_Sync_Begin := Mode.H_Visible + Mode.H_Sync_Begin;
Mode.H_Sync_End := Mode.H_Sync_Begin + Mode.H_Sync_End;
Mode.H_Total := Mode.H_Visible + Mode.H_Total;
Mode.V_Sync_Begin := Mode.V_Visible + Mode.V_Sync_Begin;
Mode.V_Sync_End := Mode.V_Sync_Begin + Mode.V_Sync_End;
Mode.V_Total := Mode.V_Visible + Mode.V_Total;
return Mode;
end Preferred_Mode;
end HW.GFX.EDID;