Graphics

Graphics in the WPCM450 involves two devices:

• The GPU (Matrox G200) is controlled by the host. It uses a piece of DRAM to store the framebuffer. This memory carve-out is configured in the memory controller. By default, the ARM9 CPU can't write to GPU memory.
• GFXI contains information such as the current video mode and resolution
• VCD captures video frames from the host into memory

device	MMIO	IRQ	description
VCD	0xb0018000	22	presumably Video Capture Device
GFXI	0xb8000300	--	presumably Graphics Information

VCD

MMIO registers at 0xb0018000:

offset	type	description
0x00	u32	address of destination buffer
0x0c	u32	video resolution

Accesses to VCD registers must be 32 bits wide.

0x0c - video resolution

bits	description
26:16	horizontal resolution (lines)
10:0	vertical resolution (pixels per line)

GFXI

MMIO registers at 0xb8000300:

offset	type	description
0x00	u8	mode
0x10	u8	horizontal resolution, low bits
0x14	u8	horizontal resolution, high bits
0x20	u8	vertical resolution, low bits
0x24	u8	vertical resolution, high bits
0x40	u8	?
0x44	u8	?
0x48	u8	?
0x58	u8	?
0x64	u8	?
0x70	u8	?

0x00 - mode

bits	description
7	1: "Hi Res", 0: VGA

References

• In the ATEN firmware, vcddev.ko and ikvmserver handle video capture together. Both have direct access to VCD and GFXI hardware.