doc/README.log was already moved to doc/develop/logging.rst but has been
recreated by an incorrect merge.

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

At present if CONFIG_LOG enabled, putting LOG_DEBUG at the top of a file
(before log.h inclusion) causes _log() to be executed for every log()
call, regardless of the build- or run-time logging level.

However there is no guarantee that the log record will actually be
displayed. If the current log level is lower than LOGL_DEBUG then it will
not be.

Add a way to signal that the log record should always be displayed and
update log_passes_filters() to handle this.

With the new behaviour, log_debug() will always log if LOG_DEBUG is
enabled.

Move log_test_syslog_nodebug() into its own file since it cannot be made
to work where it is, with LOG_DEBUG defined.

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

Replace CONFIG_(SPL_)MAX_LOG_LEVEL by the correct name as defined in
common/Kconfig:
line 668:config LOG_MAX_LEVEL
line 688:config SPL_LOG_MAX_LEVEL
line 708:config TPL_LOG_MAX_LEVEL

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Provide a log driver that broadcasts RFC 3164 messages to syslog servers.
rsyslog is one implementation of such a server.

The messages are sent to the local broadcast address 255.255.255.255 on
port 514.

The environment variable log_hostname can be used to provide the HOSTNAME
field for the messages. The optional TIMESTAMP field of RFC 3164 is not
provided.

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

At present it is possible to '#define DEBUG' at the top of a file which
causes all debug() statements in that file to become active. There is
currently no equivalent with logging, but this is a useful function.

Add a LOG_DEBUG define along with documentation.

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

The log_debug(), etc. function are documented only in the header file at
present. Add a section to README.log also.

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

Without the units these numbers are confusing. Add a comment about the
unit being 'bytes' and mention 'buildman' as the source.

Suggested-by: Lukasz Majewski <lukma@denx.de>
Signed-off-by: Simon Glass <sjg@chromium.org>

The EFI implementation does not fit into any of the existing categories.

Provide LOGC_EFI so that EFI related message can be filtered.

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

When functions return an error it propagates up the stack to the point
where it is reported. Often the error code provides enough information
about the root cause of the error that this is obvious what went wrong.

However in some cases the error may be hard to trace. For example if a
driver uses several devices to perform an operation, it may not be
obvious which one failed.

Add a log_ret() macro to help with this. This can be used to wrap any
error-return value. The logging system will then output a log record when
the original error is generated, making it easy to trace the call stack
of the error.

This macro can significantly impact code size, so its use is controlled
by a Kconfig option, which is enabled for sandbox.

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

Add some notes about recent new features.

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