add optional glyph cache for genfb
enable with options GENFB_GLYPHCACHE=n
with n being the desired size of the cache in MB. Should be enough to cache
at least 900 glyphs in whatever video mode used in order to be effective
in 32bit per pixel that's about 1MB

branches: 1.11.10;
Add genfb(4) driver for mac68k grfbus.
1, 2, 4, 8, 15, and 32 color-depths are supported.

ANSI colors on console are functional for depth >= 4.

Graphic applications based on wsfb API should work, provided
they can correctly handle fbi_fboffset and your color depth.

wsfb driver of Xorg 1.20 and mlterm-fb (framebuffer version of
x11/mlterm) work fine for depth == 1 || depth >= 8.

For depth == 8 (256 colors), graphic applications require
colormap callback, which is currently supported for some
internal graphic adapters, and only Civic (found on Quadra
AV series) was tested. Register definition and its usage are
taken from Linux. You can easily support other adapters if
Linux supports that.

Have fun, and any problem reports are welcomed!

If an EDID is available, attempt to use the screen size to influence font
selection by passing a "wantcols" value to rasops_init that is satisfied
by a font that is at least 3mm wide.

branches: 1.9.18;
Include splash with genfb.
splash.o is only included with options SPLASHSCREEN.
splash_image.o target moved to Makefile.kern.inc.

This commit was approved by matt@

branches: 1.8.6;
Merge riastradh-drm2 to HEAD.

branches: 1.7.8; 1.7.18; 1.7.22; 1.7.30;
make use of a shadow framebuffer optional, use VCONS_DONT_READ by default

branches: 1.6.2; 1.6.4;
add rasops15 too for completeness

pull in rasops16 - needed for gdium support

Provide a stub genfb_cnattach for md code to call to give a hint to the
bus driver's match function to return a higher confidence (so it can
beat out vga(4), for example). genfb needs-flag so md code can determine
if the genfb driver is present.

branches: 1.3.4; 1.3.14; 1.3.38; 1.3.48; 1.3.54;
pull in rasops1 and rasops32

branches: 1.2.2;
move genfb's PCI frontend to dev/pci

add genfb, a generic framebuffer console driver that's configured via
device properties - all it needs is width and height in pixels, stride in
bytes, depth in bits and the framebuffer address.
Features:
- unaccelerated fb console with colours and virtual consoles
- split into console handling and bus frontend
- so far there is only a PCI bus frontend which allows to mmap BARs belonging
to the graphics controller, others should be easy to add.

TODO:
- find an opaque way to change the palette ( probably pass a function
pointer as property ) since this would need to call some firmware interface
which is pretty much always MD
- find a clean way to mmap the framebuffer, just returning the physical
address works on macppc but not on other architectures. Problem is, that
we cannot rely on the address being a bus address - on macppc it is,
but for instance on sparc64 it's not.