Move this out of the common header and include it only where needed.  In
a number of cases this requires adding "struct udevice;" to avoid adding
another large header or in other cases replacing / adding missing header
files that had been pulled in, very indirectly.   Finally, we have a few
cases where we did not need to include <asm/global_data.h> at all, so
remove that include.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>

At present there is no way to disable a log driver. But the syslog driver
causes (attempted) network traffic in sandbox every time a log message
is printed, which is often.

Add a flag to enable a log driver. Adjust struct log_device to use a short
for next_filter_num so that no more memory is used for devices. Also fix
a missing line in the struct log_driver comment while here.

To maintain compatibility, enable it for all drivers for now.

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

Use the BIT() macro when creating a bitmask for the logging fields.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>

At present this just outputs the message. Update it to output whatever the
format requests.

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

It is useful to display log messages on the console. Add a simple driver
to handle this.

Note that this driver outputs to the console, which may be serial or
video. It does not specifically select serial output.

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