video: add cfb console driver for sunxi

This adds a fixed mode hdmi driver for the sunxi platform. The fixed
mode is a relatively safe 1024x768, more complete EDID handling is
currently not provided as that would mean a significant rewrite of uboot
infrastructure. Only HDMI is supported today, DT based LCD will have to
wait until a KMS driver is out.

This code is enabled when HPD detects an attached monitor, which works
well on even A13, where no HDMI signals are externally available on the
package.

Current config is such that 8MB is shaved off at the top of the RAM.
This avoids several memory handling issues, most significant is the fact
that on linux on ARM you are not allowed to remap known RAM as IO. A
clued in display driver will be able to recycle this reserved RAM in
future though.

cfbconsole was chosen as it provides the most important functionality: a
working u-boot console, allowing for the debugging of certain issues
without the need for a UART. To enable the console on HDMI, add the
following to your boot script:
	setenv stdout serial,vga
	setenv stderr serial,vga
This will sadly only take effect after the environment is read in, which
makes this hdmi console driver less universally useful as hoped.

Signed-off-by: Luc Verhaegen <libv@skynet.be>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi:video: add simplefb support

Signed-off-by: Luc Verhaegen <libv@skynet.be>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi:video: claim clocks for simplefb

This allows an updated simplefb driver in the kernel to correctly claim
clocks, so that these do not get automatically disabled by the kernels
clock framework, and so that simplefb actually does something useful for
the kernel on sunxi hw as well.

Currently, only clocks already defined in the dt today are handled. When
a sunxi KMS driver for mainline kernel happens, further clocks will have
to get defined in the sunxi dtses, and more clocks will have to be
claimed from this side as well. It is relatively pointless to try to
claim these clocks today already, as they will most likely be
significantly altered again when KMS happens.

Signed-off-by: Luc Verhaegen <libv@skynet.be>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: Kconfig unify sunxi Kconfig code

Unify the sunxi Kconfig code, instead of having seperate code blocks for
each of sun4i, sun5i and sun7i.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: Kconfig: Add CONFIG_VIDEO option to enable HDMI console support

And make this default to Y since most boards have a HDMI output.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: display: Fix clock-output-names check failure on sun5i

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: display: Add a 1920x1080 mode

Make it easy to use / test 1920x1080 by flipping a single #if.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: display: Pass around calculated clk_div and clk_double values

Rather then reading them back from the register later.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: display: 16 is not a valid clk_div value

We can use div as a clk_div for the lcdc clk, but not for the hdmi clk, so
don't try to use a clk_div of 16.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: display: Use linux-sunxi 3.4 driver values for tx clk and driver values

I don't know where the value currently in the u-boot sunxi-display driver
come from. But they cause my monitor to not sync at all with 1024x768. Use the
proven to work on many monitors values from the linux-sunxi 3.4 driver instead.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sunxi: display: Add sun5i fifo tweak from linux-sunxi 3.4 kernels

This fixes some modes / board combinations giving artifacts due to fifo
underruns.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>