Implement log framework
This patch gives users control over logging messages printed from the C
code using the LOG macros defined in debug.h Users now have the ability
to reduce the log_level at run time using the tf_log_set_max_level()
function. The default prefix string can be defined by platform by
overriding the `plat_log_get_prefix()` platform API which is also
introduced in this patch.
The new log framework results in saving of some RO data. For example,
when BL1 is built for FVP with LOG_LEVEL=LOG_LEVEL_VERBOSE, resulted
in saving 384 bytes of RO data and increase of 8 bytes of RW data. The
framework also adds about 108 bytes of code to the release build of FVP.
Fixes ARM-software/tf-issues#462
Change-Id: I476013d9c3deedfdd4c8b0b0f125665ba6250554
Co-authored-by: Eleanor Bonnici <Eleanor.bonnici@arm.com>
Signed-off-by: Soby Mathew <soby.mathew@arm.com>
diff --git a/docs/porting-guide.rst b/docs/porting-guide.rst
index c8d61ed..9798566 100644
--- a/docs/porting-guide.rst
+++ b/docs/porting-guide.rst
@@ -1014,6 +1014,21 @@
next image. This function is currently invoked in BL2 to flush this information
to the next BL image, when LOAD\_IMAGE\_V2 is enabled.
+Function : plat\_log\_get\_prefix()
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+ Argument : unsigned int
+ Return : const char *
+
+This function defines the prefix string corresponding to the `log_level` to be
+prepended to all the log output from ARM Trusted Firmware. The `log_level`
+(argument) will correspond to one of the standard log levels defined in
+debug.h. The platform can override the common implementation to define a
+different prefix string for the log output. The implementation should be
+robust to future changes that increase the number of log levels.
+
Modifications specific to a Boot Loader stage
---------------------------------------------