Driver model currently only operates after relocation is complete. In this
state U-Boot typically has a small amount of memory available. In adding
support for driver model prior to relocation we must try to use as little
memory as possible.

In addition, on some machines the memory has not be inited and/or the CPU
is not running at full speed or the data cache is off. These can reduce
execution performance, so the less initialisation that is done before
relocation the better.

An immediately-obvious improvement is to only initialise drivers which are
actually going to be used before relocation. On many boards the only such
driver is a serial UART, so this provides a very large potential benefit.

Allow drivers to mark themselves as 'pre-reloc' which means that they will
be initialised prior to relocation. This can be done either with a driver
flag or with a 'dm,pre-reloc' device tree property.

To support this, the various dm scanning function now take a 'pre_reloc_only'
parameter which indicates that only drivers marked pre-reloc should be
bound.
Signed-off-by: NSimon Glass <sjg@chromium.org>

Add a new method which removes and unbinds all drivers.
Signed-off-by: NSimon Glass <sjg@chromium.org>
Acked-by: NMarek Vasut <marex@denx.de>

The root device should be probed just like any other device. The effect of
this is to mark the device as activated, so that it can be removed (along
with its children) if required.
Signed-off-by: NSimon Glass <sjg@chromium.org>
Acked-by: NMarek Vasut <marex@denx.de>

lists.c / root.c do not include their own header and they
could potentially implement a different function. Therefore
actually include the headers.

cc: sjg@chromium.org
Signed-off-by: NJeroen Hofstee <jeroen@myspectrum.nl>
Acked-by: NSimon Glass <sjg@chromium.org>

In a very few cases we need to adjust the driver model root device, such as
when setting it up at initialisation. Add a macro to make this easier.
Signed-off-by: NSimon Glass <sjg@chromium.org>

These files don't compile in some architectures. Fix it by adding the
missing headers.
Signed-off-by: NSimon Glass <sjg@chromium.org>

using UBI and DM together leads in compiler error, as
both define a "struct device", so rename "struct device"
in include/dm/device.h to "struct udevice", as we use
linux code (MTD/UBI/UBIFS some USB code,...) and cannot
change the linux "struct device"
Signed-off-by: NHeiko Schocher <hs@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Marek Vasut <marex@denx.de>

Add driver model functionality for generic board.

This includes data structures and base code for registering devices and
uclasses (groups of devices with the same purpose, e.g. all I2C ports will
be in the same uclass).

The feature is enabled with CONFIG_DM.
Signed-off-by: NSimon Glass <sjg@chromium.org>
Signed-off-by: NMarek Vasut <marex@denx.de>
Signed-off-by: NPavel Herrmann <morpheus.ibis@gmail.com>
Signed-off-by: NViktor Křivák <viktor.krivak@gmail.com>
Signed-off-by: NTomas Hlavacek <tmshlvck@gmail.com>