[media] cx2341x.rst: add fw-decoder-registers.txt content

Convert the contents of fw-decoder-registers.txt to ReST and
add it to cx2341x.rst file.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 914 insertions, 89 deletions

diff --git a/Documentation/media/v4l-drivers/cx2341x.rst b/Documentation/media/v4l-drivers/cx2341x.rst
index 6f4ac07f52cd..f1c2d8d5978d 100644
--- a/Documentation/media/v4l-drivers/cx2341x.rst
+++ b/Documentation/media/v4l-drivers/cx2341x.rst
@@ -9,12 +9,12 @@ Decoder firmware API description
 
 
 CX2341X_DEC_PING_FW
--------------------
+~~~~~~~~~~~~~~~~~~~
 
 Enum: 0/0x00
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 This API call does nothing. It may be used to check if the firmware
 is responding.
@@ -22,22 +22,22 @@ is responding.
 
 
 CX2341X_DEC_START_PLAYBACK
---------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 1/0x01
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Begin or resume playback.
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 0 based frame number in GOP to begin playback from.
 
 Param[1]
-~~~~~~~~
+^^^^^^^^
 
 Specifies the number of muted audio frames to play before normal
 audio resumes. (This is not implemented in the firmware, leave at 0)
@@ -45,18 +45,18 @@ audio resumes. (This is not implemented in the firmware, leave at 0)
 
 
 CX2341X_DEC_STOP_PLAYBACK
--------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 2/0x02
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Ends playback and clears all decoder buffers. If PTS is not zero,
 playback stops at specified PTS.
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 Display 0=last frame, 1=black
 
@@ -68,24 +68,24 @@ Display 0=last frame, 1=black
 	to set the screen to black.
 
 Param[1]
-~~~~~~~~
+^^^^^^^^
 
 PTS low
 
 Param[2]
-~~~~~~~~
+^^^^^^^^
 
 PTS high
 
 
 
 CX2341X_DEC_SET_PLAYBACK_SPEED
-------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 3/0x03
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Playback stream at speed other than normal. There are two modes of
 operation:
@@ -96,7 +96,7 @@ operation:
 	  desired speed.
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 .. code-block:: none
 
@@ -118,7 +118,7 @@ Param[0]
 	faster playback. Instead the host should start dropping frames.
 
 Param[1]
-~~~~~~~~
+^^^^^^^^
 
 Direction: 0=forward, 1=reverse
 
@@ -128,7 +128,7 @@ Direction: 0=forward, 1=reverse
 	reverse order.
 
 Param[2]
-~~~~~~~~
+^^^^^^^^
 
 .. code-block:: none
 
@@ -138,7 +138,7 @@ Param[2]
 	    7=I, P, B frames
 
 Param[3]
-~~~~~~~~
+^^^^^^^^
 
 B frames per GOP (for reverse play only)
 
@@ -149,17 +149,17 @@ B frames per GOP (for reverse play only)
 	has to be set to the correct value in order to keep the timing correct.
 
 Param[4]
-~~~~~~~~
+^^^^^^^^
 
 Mute audio: 0=disable, 1=enable
 
 Param[5]
-~~~~~~~~
+^^^^^^^^
 
 Display 0=frame, 1=field
 
 Param[6]
-~~~~~~~~
+^^^^^^^^
 
 Specifies the number of muted audio frames to play before normal audio
 resumes. (Not implemented in the firmware, leave at 0)
@@ -167,35 +167,35 @@ resumes. (Not implemented in the firmware, leave at 0)
 
 
 CX2341X_DEC_STEP_VIDEO
-----------------------
+~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 5/0x05
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Each call to this API steps the playback to the next unit defined below
 in the current playback direction.
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 0=frame, 1=top field, 2=bottom field
 
 
 
 CX2341X_DEC_SET_DMA_BLOCK_SIZE
-------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 8/0x08
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Set DMA transfer block size. Counterpart to API 0xC9
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 DMA transfer block size in bytes. A different size may be specified
 when issuing the DMA transfer command.
@@ -203,114 +203,114 @@ when issuing the DMA transfer command.
 
 
 CX2341X_DEC_GET_XFER_INFO
--------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 9/0x09
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 This API call may be used to detect an end of stream condition.
 
 Result[0]
-~~~~~~~~~
+^^^^^^^^^
 
 Stream type
 
 Result[1]
-~~~~~~~~~
+^^^^^^^^^
 
 Address offset
 
 Result[2]
-~~~~~~~~~
+^^^^^^^^^
 
 Maximum bytes to transfer
 
 Result[3]
-~~~~~~~~~
+^^^^^^^^^
 
 Buffer fullness
 
 
 
 CX2341X_DEC_GET_DMA_STATUS
---------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 10/0x0A
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Status of the last DMA transfer
 
 Result[0]
-~~~~~~~~~
+^^^^^^^^^
 
 Bit 1 set means transfer complete
 Bit 2 set means DMA error
 Bit 3 set means linked list error
 
 Result[1]
-~~~~~~~~~
+^^^^^^^^^
 
 DMA type: 0=MPEG, 1=OSD, 2=YUV
 
 
 
 CX2341X_DEC_SCHED_DMA_FROM_HOST
--------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 11/0x0B
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Setup DMA from host operation. Counterpart to API 0xCC
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 Memory address of link list
 
 Param[1]
-~~~~~~~~
+^^^^^^^^
 
 Total # of bytes to transfer
 
 Param[2]
-~~~~~~~~
+^^^^^^^^
 
 DMA type (0=MPEG, 1=OSD, 2=YUV)
 
 
 
 CX2341X_DEC_PAUSE_PLAYBACK
---------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 13/0x0D
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Freeze playback immediately. In this mode, when internal buffers are
 full, no more data will be accepted and data request IRQs will be
 masked.
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 Display: 0=last frame, 1=black
 
 
 
 CX2341X_DEC_HALT_FW
--------------------
+~~~~~~~~~~~~~~~~~~~
 
 Enum: 14/0x0E
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 The firmware is halted and no further API calls are serviced until
 the firmware is uploaded again.
@@ -318,34 +318,34 @@ the firmware is uploaded again.
 
 
 CX2341X_DEC_SET_STANDARD
-------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 16/0x10
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Selects display standard
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 0=NTSC, 1=PAL
 
 
 
 CX2341X_DEC_GET_VERSION
------------------------
+~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 17/0x11
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Returns decoder firmware version information
 
 Result[0]
-~~~~~~~~~
+^^^^^^^^^
 
 Version bitmask:
 	- Bits  0:15 build
@@ -355,77 +355,77 @@ Version bitmask:
 
 
 CX2341X_DEC_SET_STREAM_INPUT
-----------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 20/0x14
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Select decoder stream input port
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 0=memory (default), 1=streaming
 
 
 
 CX2341X_DEC_GET_TIMING_INFO
----------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 21/0x15
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Returns timing information from start of playback
 
 Result[0]
-~~~~~~~~~
+^^^^^^^^^
 
 Frame count by decode order
 
 Result[1]
-~~~~~~~~~
+^^^^^^^^^
 
 Video PTS bits 0:31 by display order
 
 Result[2]
-~~~~~~~~~
+^^^^^^^^^
 
 Video PTS bit 32 by display order
 
 Result[3]
-~~~~~~~~~
+^^^^^^^^^
 
 SCR bits 0:31 by display order
 
 Result[4]
-~~~~~~~~~
+^^^^^^^^^
 
 SCR bit 32 by display order
 
 
 
 CX2341X_DEC_SET_AUDIO_MODE
---------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 22/0x16
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Select audio mode
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 Dual mono mode action
 	0=Stereo, 1=Left, 2=Right, 3=Mono, 4=Swap, -1=Unchanged
 
 Param[1]
-~~~~~~~~
+^^^^^^^^
 
 Stereo mode action:
 	0=Stereo, 1=Left, 2=Right, 3=Mono, 4=Swap, -1=Unchanged
@@ -433,18 +433,18 @@ Stereo mode action:
 
 
 CX2341X_DEC_SET_EVENT_NOTIFICATION
-----------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 23/0x17
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Setup firmware to notify the host about a particular event.
 Counterpart to API 0xD5
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 Event:
 	- 0=Audio mode change between mono, (joint) stereo and dual channel.
@@ -453,112 +453,937 @@ Event:
 	- 5=Some sync event: goes off once per frame.
 
 Param[1]
-~~~~~~~~
+^^^^^^^^
 
 Notification 0=disabled, 1=enabled
 
 Param[2]
-~~~~~~~~
+^^^^^^^^
 
 Interrupt bit
 
 Param[3]
-~~~~~~~~
+^^^^^^^^
 
 Mailbox slot, -1 if no mailbox required.
 
 
 
 CX2341X_DEC_SET_DISPLAY_BUFFERS
--------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 24/0x18
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Number of display buffers. To decode all frames in reverse playback you
 must use nine buffers.
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 0=six buffers, 1=nine buffers
 
 
 
 CX2341X_DEC_EXTRACT_VBI
------------------------
+~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 25/0x19
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Extracts VBI data
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 0=extract from extension & user data, 1=extract from private packets
 
 Result[0]
-~~~~~~~~~
+^^^^^^^^^
 
 VBI table location
 
 Result[1]
-~~~~~~~~~
+^^^^^^^^^
 
 VBI table size
 
 
 
 CX2341X_DEC_SET_DECODER_SOURCE
-------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 26/0x1A
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Selects decoder source. Ensure that the parameters passed to this
 API match the encoder settings.
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 Mode: 0=MPEG from host, 1=YUV from encoder, 2=YUV from host
 
 Param[1]
-~~~~~~~~
+^^^^^^^^
 
 YUV picture width
 
 Param[2]
-~~~~~~~~
+^^^^^^^^
 
 YUV picture height
 
 Param[3]
-~~~~~~~~
+^^^^^^^^
 
 Bitmap: see Param[0] of API 0xBD
 
 
 
 CX2341X_DEC_SET_PREBUFFERING
-----------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Enum: 30/0x1E
 
 Description
-~~~~~~~~~~~
+^^^^^^^^^^^
 
 Decoder prebuffering, when enabled up to 128KB are buffered for
 streams <8mpbs or 640KB for streams >8mbps
 
 Param[0]
-~~~~~~~~
+^^^^^^^^
 
 0=off, 1=on
+
+PVR350 Video decoder registers 0x02002800 -> 0x02002B00
+-------------------------------------------------------
+
+Author: Ian Armstrong <ian@iarmst.demon.co.uk>
+
+Version: v0.4
+
+Date: 12 March 2007
+
+
+This list has been worked out through trial and error. There will be mistakes
+and omissions. Some registers have no obvious effect so it's hard to say what
+they do, while others interact with each other, or require a certain load
+sequence. Horizontal filter setup is one example, with six registers working
+in unison and requiring a certain load sequence to correctly configure. The
+indexed colour palette is much easier to set at just two registers, but again
+it requires a certain load sequence.
+
+Some registers are fussy about what they are set to. Load in a bad value & the
+decoder will fail. A firmware reload will often recover, but sometimes a reset
+is required. For registers containing size information, setting them to 0 is
+generally a bad idea. For other control registers i.e. 2878, you'll only find
+out what values are bad when it hangs.
+
+.. code-block:: none
+
+	--------------------------------------------------------------------------------
+	2800
+	bit 0
+		Decoder enable
+		0 = disable
+		1 = enable
+	--------------------------------------------------------------------------------
+	2804
+	bits 0:31
+		Decoder horizontal Y alias register 1
+	---------------
+	2808
+	bits 0:31
+		Decoder horizontal Y alias register 2
+	---------------
+	280C
+	bits 0:31
+		Decoder horizontal Y alias register 3
+	---------------
+	2810
+	bits 0:31
+		Decoder horizontal Y alias register 4
+	---------------
+	2814
+	bits 0:31
+		Decoder horizontal Y alias register 5
+	---------------
+	2818
+	bits 0:31
+		Decoder horizontal Y alias trigger
+
+	These six registers control the horizontal aliasing filter for the Y plane.
+	The first five registers must all be loaded before accessing the trigger
+	(2818), as this register actually clocks the data through for the first
+	five.
+
+	To correctly program set the filter, this whole procedure must be done 16
+	times. The actual register contents are copied from a lookup-table in the
+	firmware which contains 4 different filter settings.
+
+	--------------------------------------------------------------------------------
+	281C
+	bits 0:31
+		Decoder horizontal UV alias register 1
+	---------------
+	2820
+	bits 0:31
+		Decoder horizontal UV alias register 2
+	---------------
+	2824
+	bits 0:31
+		Decoder horizontal UV alias register 3
+	---------------
+	2828
+	bits 0:31
+		Decoder horizontal UV alias register 4
+	---------------
+	282C
+	bits 0:31
+		Decoder horizontal UV alias register 5
+	---------------
+	2830
+	bits 0:31
+		Decoder horizontal UV alias trigger
+
+	These six registers control the horizontal aliasing for the UV plane.
+	Operation is the same as the Y filter, with 2830 being the trigger
+	register.
+
+	--------------------------------------------------------------------------------
+	2834
+	bits 0:15
+		Decoder Y source width in pixels
+
+	bits 16:31
+		Decoder Y destination width in pixels
+	---------------
+	2838
+	bits 0:15
+		Decoder UV source width in pixels
+
+	bits 16:31
+		Decoder UV destination width in pixels
+
+	NOTE: For both registers, the resulting image must be fully visible on
+	screen. If the image exceeds the right edge both the source and destination
+	size must be adjusted to reflect the visible portion. For the source width,
+	you must take into account the scaling when calculating the new value.
+	--------------------------------------------------------------------------------
+
+	283C
+	bits 0:31
+		Decoder Y horizontal scaling
+			Normally = Reg 2854 >> 2
+	---------------
+	2840
+	bits 0:31
+		Decoder ?? unknown - horizontal scaling
+		Usually 0x00080514
+	---------------
+	2844
+	bits 0:31
+		Decoder UV horizontal scaling
+		Normally = Reg 2854 >> 2
+	---------------
+	2848
+	bits 0:31
+		Decoder ?? unknown - horizontal scaling
+		Usually 0x00100514
+	---------------
+	284C
+	bits 0:31
+		Decoder ?? unknown - Y plane
+		Usually 0x00200020
+	---------------
+	2850
+	bits 0:31
+		Decoder ?? unknown - UV plane
+		Usually 0x00200020
+	---------------
+	2854
+	bits 0:31
+		Decoder 'master' value for horizontal scaling
+	---------------
+	2858
+	bits 0:31
+		Decoder ?? unknown
+		Usually 0
+	---------------
+	285C
+	bits 0:31
+		Decoder ?? unknown
+		Normally = Reg 2854 >> 1
+	---------------
+	2860
+	bits 0:31
+		Decoder ?? unknown
+		Usually 0
+	---------------
+	2864
+	bits 0:31
+		Decoder ?? unknown
+		Normally = Reg 2854 >> 1
+	---------------
+	2868
+	bits 0:31
+		Decoder ?? unknown
+		Usually 0
+
+	Most of these registers either control horizontal scaling, or appear linked
+	to it in some way. Register 2854 contains the 'master' value & the other
+	registers can be calculated from that one. You must also remember to
+	correctly set the divider in Reg 2874.
+
+	To enlarge:
+		Reg 2854 = (source_width * 0x00200000) / destination_width
+		Reg 2874 = No divide
+
+	To reduce from full size down to half size:
+		Reg 2854 = (source_width/2 * 0x00200000) / destination width
+		Reg 2874 = Divide by 2
+
+	To reduce from half size down to quarter size:
+		Reg 2854 = (source_width/4 * 0x00200000) / destination width
+		Reg 2874 = Divide by 4
+
+	The result is always rounded up.
+
+	--------------------------------------------------------------------------------
+	286C
+	bits 0:15
+		Decoder horizontal Y buffer offset
+
+	bits 15:31
+		Decoder horizontal UV buffer offset
+
+	Offset into the video image buffer. If the offset is gradually incremented,
+	the on screen image will move left & wrap around higher up on the right.
+
+	--------------------------------------------------------------------------------
+	2870
+	bits 0:15
+		Decoder horizontal Y output offset
+
+	bits 16:31
+		Decoder horizontal UV output offset
+
+	Offsets the actual video output. Controls output alignment of the Y & UV
+	planes. The higher the value, the greater the shift to the left. Use
+	reg 2890 to move the image right.
+
+	--------------------------------------------------------------------------------
+	2874
+	bits 0:1
+		Decoder horizontal Y output size divider
+		00 = No divide
+		01 = Divide by 2
+		10 = Divide by 3
+
+	bits 4:5
+		Decoder horizontal UV output size divider
+		00 = No divide
+		01 = Divide by 2
+		10 = Divide by 3
+
+	bit 8
+		Decoder ?? unknown
+		0 = Normal
+		1 = Affects video output levels
+
+	bit 16
+		Decoder ?? unknown
+		0 = Normal
+		1 = Disable horizontal filter
+
+	--------------------------------------------------------------------------------
+	2878
+	bit 0
+		?? unknown
+
+	bit 1
+		osd on/off
+		0 = osd off
+		1 = osd on
+
+	bit 2
+		Decoder + osd video timing
+		0 = NTSC
+		1 = PAL
+
+	bits 3:4
+		?? unknown
+
+	bit 5
+		Decoder + osd
+		Swaps upper & lower fields
+
+	--------------------------------------------------------------------------------
+	287C
+	bits 0:10
+		Decoder & osd ?? unknown
+		Moves entire screen horizontally. Starts at 0x005 with the screen
+		shifted heavily to the right. Incrementing in steps of 0x004 will
+		gradually shift the screen to the left.
+
+	bits 11:31
+		?? unknown
+
+	Normally contents are 0x00101111 (NTSC) or 0x1010111d (PAL)
+
+	--------------------------------------------------------------------------------
+	2880  --------    ?? unknown
+	2884  --------    ?? unknown
+	--------------------------------------------------------------------------------
+	2888
+	bit 0
+		Decoder + osd ?? unknown
+		0 = Normal
+		1 = Misaligned fields (Correctable through 289C & 28A4)
+
+	bit 4
+		?? unknown
+
+	bit 8
+		?? unknown
+
+	Warning: Bad values will require a firmware reload to recover.
+			Known to be bad are 0x000,0x011,0x100,0x111
+	--------------------------------------------------------------------------------
+	288C
+	bits 0:15
+		osd ?? unknown
+		Appears to affect the osd position stability. The higher the value the
+		more unstable it becomes. Decoder output remains stable.
+
+	bits 16:31
+		osd ?? unknown
+		Same as bits 0:15
+
+	--------------------------------------------------------------------------------
+	2890
+	bits 0:11
+		Decoder output horizontal offset.
+
+	Horizontal offset moves the video image right. A small left shift is
+	possible, but it's better to use reg 2870 for that due to its greater
+	range.
+
+	NOTE: Video corruption will occur if video window is shifted off the right
+	edge. To avoid this read the notes for 2834 & 2838.
+	--------------------------------------------------------------------------------
+	2894
+	bits 0:23
+		Decoder output video surround colour.
+
+	Contains the colour (in yuv) used to fill the screen when the video is
+	running in a window.
+	--------------------------------------------------------------------------------
+	2898
+	bits 0:23
+		Decoder video window colour
+		Contains the colour (in yuv) used to fill the video window when the
+		video is turned off.
+
+	bit 24
+		Decoder video output
+		0 = Video on
+		1 = Video off
+
+	bit 28
+		Decoder plane order
+		0 = Y,UV
+		1 = UV,Y
+
+	bit 29
+		Decoder second plane byte order
+		0 = Normal (UV)
+		1 = Swapped (VU)
+
+	In normal usage, the first plane is Y & the second plane is UV. Though the
+	order of the planes can be swapped, only the byte order of the second plane
+	can be swapped. This isn't much use for the Y plane, but can be useful for
+	the UV plane.
+
+	--------------------------------------------------------------------------------
+	289C
+	bits 0:15
+		Decoder vertical field offset 1
+
+	bits 16:31
+		Decoder vertical field offset 2
+
+	Controls field output vertical alignment. The higher the number, the lower
+	the image on screen. Known starting values are 0x011E0017 (NTSC) &
+	0x01500017 (PAL)
+	--------------------------------------------------------------------------------
+	28A0
+	bits 0:15
+		Decoder & osd width in pixels
+
+	bits 16:31
+		Decoder & osd height in pixels
+
+	All output from the decoder & osd are disabled beyond this area. Decoder
+	output will simply go black outside of this region. If the osd tries to
+	exceed this area it will become corrupt.
+	--------------------------------------------------------------------------------
+	28A4
+	bits 0:11
+		osd left shift.
+
+	Has a range of 0x770->0x7FF. With the exception of 0, any value outside of
+	this range corrupts the osd.
+	--------------------------------------------------------------------------------
+	28A8
+	bits 0:15
+		osd vertical field offset 1
+
+	bits 16:31
+		osd vertical field offset 2
+
+	Controls field output vertical alignment. The higher the number, the lower
+	the image on screen. Known starting values are 0x011E0017 (NTSC) &
+	0x01500017 (PAL)
+	--------------------------------------------------------------------------------
+	28AC  --------    ?? unknown
+	|
+	V
+	28BC  --------    ?? unknown
+	--------------------------------------------------------------------------------
+	28C0
+	bit 0
+		Current output field
+		0 = first field
+		1 = second field
+
+	bits 16:31
+		Current scanline
+		The scanline counts from the top line of the first field
+		through to the last line of the second field.
+	--------------------------------------------------------------------------------
+	28C4  --------    ?? unknown
+	|
+	V
+	28F8  --------    ?? unknown
+	--------------------------------------------------------------------------------
+	28FC
+	bit 0
+		?? unknown
+		0 = Normal
+		1 = Breaks decoder & osd output
+	--------------------------------------------------------------------------------
+	2900
+	bits 0:31
+		Decoder vertical Y alias register 1
+	---------------
+	2904
+	bits 0:31
+		Decoder vertical Y alias register 2
+	---------------
+	2908
+	bits 0:31
+		Decoder vertical Y alias trigger
+
+	These three registers control the vertical aliasing filter for the Y plane.
+	Operation is similar to the horizontal Y filter (2804). The only real
+	difference is that there are only two registers to set before accessing
+	the trigger register (2908). As for the horizontal filter, the values are
+	taken from a lookup table in the firmware, and the procedure must be
+	repeated 16 times to fully program the filter.
+	--------------------------------------------------------------------------------
+	290C
+	bits 0:31
+		Decoder vertical UV alias register 1
+	---------------
+	2910
+	bits 0:31
+		Decoder vertical UV alias register 2
+	---------------
+	2914
+	bits 0:31
+		Decoder vertical UV alias trigger
+
+	These three registers control the vertical aliasing filter for the UV
+	plane. Operation is the same as the Y filter, with 2914 being the trigger.
+	--------------------------------------------------------------------------------
+	2918
+	bits 0:15
+		Decoder Y source height in pixels
+
+	bits 16:31
+		Decoder Y destination height in pixels
+	---------------
+	291C
+	bits 0:15
+		Decoder UV source height in pixels divided by 2
+
+	bits 16:31
+		Decoder UV destination height in pixels
+
+	NOTE: For both registers, the resulting image must be fully visible on
+	screen. If the image exceeds the bottom edge both the source and
+	destination size must be adjusted to reflect the visible portion. For the
+	source height, you must take into account the scaling when calculating the
+	new value.
+	--------------------------------------------------------------------------------
+	2920
+	bits 0:31
+		Decoder Y vertical scaling
+		Normally = Reg 2930 >> 2
+	---------------
+	2924
+	bits 0:31
+		Decoder Y vertical scaling
+		Normally = Reg 2920 + 0x514
+	---------------
+	2928
+	bits 0:31
+		Decoder UV vertical scaling
+		When enlarging = Reg 2930 >> 2
+		When reducing = Reg 2930 >> 3
+	---------------
+	292C
+	bits 0:31
+		Decoder UV vertical scaling
+		Normally = Reg 2928 + 0x514
+	---------------
+	2930
+	bits 0:31
+		Decoder 'master' value for vertical scaling
+	---------------
+	2934
+	bits 0:31
+		Decoder ?? unknown - Y vertical scaling
+	---------------
+	2938
+	bits 0:31
+		Decoder Y vertical scaling
+		Normally = Reg 2930
+	---------------
+	293C
+	bits 0:31
+		Decoder ?? unknown - Y vertical scaling
+	---------------
+	2940
+	bits 0:31
+		Decoder UV vertical scaling
+		When enlarging = Reg 2930 >> 1
+		When reducing = Reg 2930
+	---------------
+	2944
+	bits 0:31
+		Decoder ?? unknown - UV vertical scaling
+	---------------
+	2948
+	bits 0:31
+		Decoder UV vertical scaling
+		Normally = Reg 2940
+	---------------
+	294C
+	bits 0:31
+		Decoder ?? unknown - UV vertical scaling
+
+	Most of these registers either control vertical scaling, or appear linked
+	to it in some way. Register 2930 contains the 'master' value & all other
+	registers can be calculated from that one. You must also remember to
+	correctly set the divider in Reg 296C
+
+	To enlarge:
+		Reg 2930 = (source_height * 0x00200000) / destination_height
+		Reg 296C = No divide
+
+	To reduce from full size down to half size:
+		Reg 2930 = (source_height/2 * 0x00200000) / destination height
+		Reg 296C = Divide by 2
+
+	To reduce from half down to quarter.
+		Reg 2930 = (source_height/4 * 0x00200000) / destination height
+		Reg 296C = Divide by 4
+
+	--------------------------------------------------------------------------------
+	2950
+	bits 0:15
+		Decoder Y line index into display buffer, first field
+
+	bits 16:31
+		Decoder Y vertical line skip, first field
+	--------------------------------------------------------------------------------
+	2954
+	bits 0:15
+		Decoder Y line index into display buffer, second field
+
+	bits 16:31
+		Decoder Y vertical line skip, second field
+	--------------------------------------------------------------------------------
+	2958
+	bits 0:15
+		Decoder UV line index into display buffer, first field
+
+	bits 16:31
+		Decoder UV vertical line skip, first field
+	--------------------------------------------------------------------------------
+	295C
+	bits 0:15
+		Decoder UV line index into display buffer, second field
+
+	bits 16:31
+		Decoder UV vertical line skip, second field
+	--------------------------------------------------------------------------------
+	2960
+	bits 0:15
+		Decoder destination height minus 1
+
+	bits 16:31
+		Decoder destination height divided by 2
+	--------------------------------------------------------------------------------
+	2964
+	bits 0:15
+		Decoder Y vertical offset, second field
+
+	bits 16:31
+		Decoder Y vertical offset, first field
+
+	These two registers shift the Y plane up. The higher the number, the
+	greater the shift.
+	--------------------------------------------------------------------------------
+	2968
+	bits 0:15
+		Decoder UV vertical offset, second field
+
+	bits 16:31
+		Decoder UV vertical offset, first field
+
+	These two registers shift the UV plane up. The higher the number, the
+	greater the shift.
+	--------------------------------------------------------------------------------
+	296C
+	bits 0:1
+		Decoder vertical Y output size divider
+		00 = No divide
+		01 = Divide by 2
+		10 = Divide by 4
+
+	bits 8:9
+		Decoder vertical UV output size divider
+		00 = No divide
+		01 = Divide by 2
+		10 = Divide by 4
+	--------------------------------------------------------------------------------
+	2970
+	bit 0
+		Decoder ?? unknown
+		0 = Normal
+		1 = Affect video output levels
+
+	bit 16
+		Decoder ?? unknown
+		0 = Normal
+		1 = Disable vertical filter
+
+	--------------------------------------------------------------------------------
+	2974  --------   ?? unknown
+	|
+	V
+	29EF  --------   ?? unknown
+	--------------------------------------------------------------------------------
+	2A00
+	bits 0:2
+		osd colour mode
+		000 = 8 bit indexed
+		001 = 16 bit (565)
+		010 = 15 bit (555)
+		011 = 12 bit (444)
+		100 = 32 bit (8888)
+
+	bits 4:5
+		osd display bpp
+		01 = 8 bit
+		10 = 16 bit
+		11 = 32 bit
+
+	bit 8
+		osd global alpha
+		0 = Off
+		1 = On
+
+	bit 9
+		osd local alpha
+		0 = Off
+		1 = On
+
+	bit 10
+		osd colour key
+		0 = Off
+		1 = On
+
+	bit 11
+		osd ?? unknown
+		Must be 1
+
+	bit 13
+		osd colour space
+		0 = ARGB
+		1 = AYVU
+
+	bits 16:31
+		osd ?? unknown
+		Must be 0x001B (some kind of buffer pointer ?)
+
+	When the bits-per-pixel is set to 8, the colour mode is ignored and
+	assumed to be 8 bit indexed. For 16 & 32 bits-per-pixel the colour depth
+	is honoured, and when using a colour depth that requires fewer bytes than
+	allocated the extra bytes are used as padding. So for a 32 bpp with 8 bit
+	index colour, there are 3 padding bytes per pixel. It's also possible to
+	select 16bpp with a 32 bit colour mode. This results in the pixel width
+	being doubled, but the color key will not work as expected in this mode.
+
+	Colour key is as it suggests. You designate a colour which will become
+	completely transparent. When using 565, 555 or 444 colour modes, the
+	colour key is always 16 bits wide. The colour to key on is set in Reg 2A18.
+
+	Local alpha works differently depending on the colour mode. For 32bpp & 8
+	bit indexed, local alpha is a per-pixel 256 step transparency, with 0 being
+	transparent and 255 being solid. For the 16bpp modes 555 & 444, the unused
+	bit(s) act as a simple transparency switch, with 0 being solid & 1 being
+	fully transparent. There is no local alpha support for 16bit 565.
+
+	Global alpha is a 256 step transparency that applies to the entire osd,
+	with 0 being transparent & 255 being solid.
+
+	It's possible to combine colour key, local alpha & global alpha.
+	--------------------------------------------------------------------------------
+	2A04
+	bits 0:15
+		osd x coord for left edge
+
+	bits 16:31
+		osd y coord for top edge
+	---------------
+	2A08
+	bits 0:15
+		osd x coord for right edge
+
+	bits 16:31
+		osd y coord for bottom edge
+
+	For both registers, (0,0) = top left corner of the display area. These
+	registers do not control the osd size, only where it's positioned & how
+	much is visible. The visible osd area cannot exceed the right edge of the
+	display, otherwise the osd will become corrupt. See reg 2A10 for
+	setting osd width.
+	--------------------------------------------------------------------------------
+	2A0C
+	bits 0:31
+		osd buffer index
+
+	An index into the osd buffer. Slowly incrementing this moves the osd left,
+	wrapping around onto the right edge
+	--------------------------------------------------------------------------------
+	2A10
+	bits 0:11
+		osd buffer 32 bit word width
+
+	Contains the width of the osd measured in 32 bit words. This means that all
+	colour modes are restricted to a byte width which is divisible by 4.
+	--------------------------------------------------------------------------------
+	2A14
+	bits 0:15
+		osd height in pixels
+
+	bits 16:32
+		osd line index into buffer
+		osd will start displaying from this line.
+	--------------------------------------------------------------------------------
+	2A18
+	bits 0:31
+		osd colour key
+
+	Contains the colour value which will be transparent.
+	--------------------------------------------------------------------------------
+	2A1C
+	bits 0:7
+		osd global alpha
+
+	Contains the global alpha value (equiv ivtvfbctl --alpha XX)
+	--------------------------------------------------------------------------------
+	2A20  --------    ?? unknown
+	|
+	V
+	2A2C  --------    ?? unknown
+	--------------------------------------------------------------------------------
+	2A30
+	bits 0:7
+		osd colour to change in indexed palette
+	---------------
+	2A34
+	bits 0:31
+		osd colour for indexed palette
+
+	To set the new palette, first load the index of the colour to change into
+	2A30, then load the new colour into 2A34. The full palette is 256 colours,
+	so the index range is 0x00-0xFF
+	--------------------------------------------------------------------------------
+	2A38  --------    ?? unknown
+	2A3C  --------    ?? unknown
+	--------------------------------------------------------------------------------
+	2A40
+	bits 0:31
+		osd ?? unknown
+
+	Affects overall brightness, wrapping around to black
+	--------------------------------------------------------------------------------
+	2A44
+	bits 0:31
+		osd ?? unknown
+
+	Green tint
+	--------------------------------------------------------------------------------
+	2A48
+	bits 0:31
+		osd ?? unknown
+
+	Red tint
+	--------------------------------------------------------------------------------
+	2A4C
+	bits 0:31
+		osd ?? unknown
+
+	Affects overall brightness, wrapping around to black
+	--------------------------------------------------------------------------------
+	2A50
+	bits 0:31
+		osd ?? unknown
+
+	Colour shift
+	--------------------------------------------------------------------------------
+	2A54
+	bits 0:31
+		osd ?? unknown
+
+	Colour shift
+	--------------------------------------------------------------------------------
+	2A58  --------    ?? unknown
+	|
+	V
+	2AFC  --------    ?? unknown
+	--------------------------------------------------------------------------------
+	2B00
+	bit 0
+		osd filter control
+		0 = filter off
+		1 = filter on
+
+	bits 1:4
+		osd ?? unknown
+
+	--------------------------------------------------------------------------------
+