Some architectures use a cached framebuffer and flush the cache as needed
so that changes are visible. This is supported by U-Boot.

However x86 uses an uncached framebuffer with a 'write-combining' feature
to speed up writes.  Reads are permitted but they are extremely expensive.

Unfortunately, reading from the frame buffer is quite common, e.g. to
scroll it. This makes scrolling very slow.

Add a new feature which supports copying modified parts of the frame
buffer to the uncached hardware buffer. This speeds up scrolling by at
least 10x on x86 so the extra complexity cost seems worth it.

As a starting point, add the Kconfig, update the video structures to keep
track of the buffer and add a function to do the copy.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

Add a few notes to explain the purpose of each member of this struct.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

These files should not be included in meson header files. Drop them and
tidy up the affected C files.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

The video console for DM_VIDEO compliant drivers only understands a very
small number of ANSI sequences. First and foremost it misses the "reverse
video" command, which is used by our own bootmenu command to highlight
the selected entry.

To avoid forcing people to use their imagination when using the
bootmenu, let's just implement the rather simple reverse effect. We need
to store the background colour index for that, so that we can
recalculate both the foreground and background colour pixel values.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
[agust: merged BG color escape seq change to fix "ut dm video_ansi" test]
Signed-off-by: Anatolij Gustschin <agust@denx.de>

At present line_length is always calculated in video_post_probe(). But
some hardware may use a different line length, e.g. with a 1366-wide
display.

Allow the driver to set this value if needed.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>

It is useful to be able to invert the colours in some cases so that the
text matches the background colour. Add a parameter to the function to
support this.

It is strange that function takes a private data structure from another
driver as an argument. It seems better to pass the device and have the
function internally work out how to find its required information.

Signed-off-by: Simon Glass <sjg@chromium.org>

Add a little more information to one comment and update the guard comment
to be more accurate.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>

All driver-model operation should return an error code. Adjust this
function to do so also.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>

At present there are many situations where sandbox syncs the display to
the SDL frame buffer. This is a very expensive operation but is only
needed every now and then. Update video_sync() so that we can specify
whether this operation is really needed.

At present this flag is not used on other architectures. It could also
be used for reducing writeback-cache flushes but the benefit of that would
need to be investigated.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>

video_init, video_putc and video_puts functions are not implemented
anywhere, remove their declaration from the header.

Signed-off-by: Liviu Dudau <liviu.dudau@foss.arm.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>