[PATCH v2 1/2] libtracefs: Document marker APIs

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

Added man pages describing these functions:
 tracefs_print_init();
 tracefs_printf();
 tracefs_vprintf();
 tracefs_print_close();
 tracefs_binary_init();
 tracefs_binary_write();
 tracefs_binary_close();

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-marker.txt     | 116 ++++++++++++++++++++++++
 Documentation/libtracefs-marker_raw.txt | 102 +++++++++++++++++++++
 Documentation/libtracefs.txt            |  10 ++
 3 files changed, 228 insertions(+)
 create mode 100644 Documentation/libtracefs-marker.txt
 create mode 100644 Documentation/libtracefs-marker_raw.txt

diff --git a/Documentation/libtracefs-marker.txt b/Documentation/libtracefs-marker.txt
new file mode 100644
index 0000000..1905662
--- /dev/null
+++ b/Documentation/libtracefs-marker.txt
@@ -0,0 +1,116 @@
+libtracefs(3)
+=============
+
+NAME
+----
+tracefs_print_init, tracefs_print_close, tracefs_printf, tracefs_vprintf -
+Open, close and write formated strings in the trace buffer.
+
+SYNOPSIS
+--------
+[verse]
+--
+*#include <tracefs.h>*
+
+int *tracefs_print_init*(struct tracefs_instance pass:[*]_instance_);
+int *tracefs_printf*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]_fmt_, _..._);
+int *tracefs_vprintf*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]_fmt_, va_list _ap_);
+void *tracefs_print_close*(struct tracefs_instance pass:[*]_instance_);
+
+--
+
+DESCRIPTION
+-----------
+Set of functions to write formated strings in the trace buffer.
+See Documentation/trace/ftrace.rst from the Linux kernel tree for more information about writing
+data from user space in the trace buffer. All these APIs have _instance_ as a first argument. If
+NULL is passed as _instance_, the top trace instance is used.
+
+The _tracefs_print_init()_ function initializes the library for writing into the trace buffer of
+the selected _instance_. It is not mandatory to call this API before writing strings, any of
+the printf APIs will call it automatically, if the library is not yet initialized. But calling
+_tracefs_print_init()_ in advance will speed up the writing.
+
+The _tracefs_printf()_ function writes a formatted string in the trace buffer of the selected
+_instance_. The _fmt_ argument is a string in printf format, followed by variable arguments _..._.
+
+The _tracefs_vprintf()_ function writes a formatted string in the trace buffer of the selected
+_instance_. The _fmt_ argument is a string in printf format, followed by list _ap_ of arguments.
+
+The _tracefs_print_close()_ function closes the resources, used by the library for writing in
+the trace buffer of the selected instance.
+
+RETURN VALUE
+------------
+The _tracefs_print_init()_, _tracefs_printf()_, and _tracefs_vprintf()_ functions return 0 if
+the operation is successful, or -1 in case of an error.
+
+EXAMPLE
+-------
+[source,c]
+--
+#include <tracefs.h>
+
+if (tracefs_print_init(NULL) < 0) {
+ /* Failed to initialize the library for writing in the trace buffer of the top trace instance */
+}
+
+void foo_print(char *format, ...)
+{
+	va_list ap;
+	va_start(ap, format);
+	if (tracefs_vprintf(NULL, format, ap) < 0) {
+		/* Failed to print in the trace buffer */
+	}
+	va_end(ap);
+}
+
+void foo_print_string(char *message)
+{
+	if (tracefs_printf(NULL, "Message from user space: %s", message) < 0) {
+		/* Failed to print in the trace buffer */
+	}
+}
+
+tracefs_print_close();
+--
+FILES
+-----
+[verse]
+--
+*tracefs.h*
+	Header file to include in order to have access to the library APIs.
+*-ltracefs*
+	Linker switch to add when building a program that uses the library.
+--
+
+SEE ALSO
+--------
+_libtracefs(3)_,
+_libtraceevent(3)_,
+_trace-cmd(1)_,
+Documentation/trace/ftrace.rst from the Linux kernel tree
+
+AUTHOR
+------
+[verse]
+--
+*Steven Rostedt* <rostedt@goodmis.org>
+*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>
+--
+REPORTING BUGS
+--------------
+Report bugs to  <linux-trace-devel@vger.kernel.org>
+
+LICENSE
+-------
+libtracefs is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
+
+COPYING
+-------
+Copyright \(C) 2021 VMware, Inc. Free use of this software is granted under
+the terms of the GNU Public License (GPL).
diff --git a/Documentation/libtracefs-marker_raw.txt b/Documentation/libtracefs-marker_raw.txt
new file mode 100644
index 0000000..f53ac72
--- /dev/null
+++ b/Documentation/libtracefs-marker_raw.txt
@@ -0,0 +1,102 @@
+libtracefs(3)
+=============
+
+NAME
+----
+tracefs_binary_init, tracefs_binary_close, tracefs_binary_write -
+Open, close and write binary data in the trace buffer.
+
+SYNOPSIS
+--------
+[verse]
+--
+*#include <tracefs.h>*
+
+int *tracefs_binary_init*(struct tracefs_instance pass:[*]_instance_);
+int *tracefs_binary_write*(struct tracefs_instance pass:[*]_instance_, void pass:[*]_data_, int _len_);
+void *tracefs_binary_close*(struct tracefs_instance pass:[*]_instance_);
+
+--
+
+DESCRIPTION
+-----------
+Set of functions to write binary data in the trace buffer.
+See Documentation/trace/ftrace.rst from the Linux kernel tree for more information about writing
+data from user space in the trace buffer. All these APIs have _instance_ as a first argument. If
+NULL is passed as _instance_, the top trace instance is used.
+
+The _tracefs_binary_init()_ function initializes the library for writing into the trace buffer of
+the selected _instance_. It is not mandatory to call this API before writing data, the
+_tracefs_binary_write()_ will call it automatically, if the library is not yet initialized.
+But calling _tracefs_binary_init()_ in advance will speed up the writing.
+
+The _tracefs_binary_write()_ function writes a binary data in the trace buffer of the selected
+_instance_. The _data_ points to the data with length _len_, that is going to be written in
+the trace buffer.
+
+The _tracefs_binary_close()_ function closes the resources, used by the library for writing in
+the trace buffer of the selected instance.
+
+RETURN VALUE
+------------
+The _tracefs_binary_init()_, and _tracefs_binary_write()_ functions return 0 if the operation is
+successful, or -1 in case of an error.
+
+EXAMPLE
+-------
+[source,c]
+--
+#include <tracefs.h>
+
+if (tracefs_binary_init(NULL) < 0) {
+ /* Failed to initialize the library for writing in the trace buffer of the top trace instance */
+}
+
+unsigned int data = 0xdeadbeef;
+
+	if (tracefs_binary_write(NULL, &data, sizeof(data)) < 0) {
+		/* Failed to write in the trace buffer */
+	}
+
+tracefs_binary_close();
+--
+FILES
+-----
+[verse]
+--
+*tracefs.h*
+	Header file to include in order to have access to the library APIs.
+*-ltracefs*
+	Linker switch to add when building a program that uses the library.
+--
+
+SEE ALSO
+--------
+_libtracefs(3)_,
+_libtraceevent(3)_,
+_trace-cmd(1)_,
+Documentation/trace/ftrace.rst from the Linux kernel tree
+
+AUTHOR
+------
+[verse]
+--
+*Steven Rostedt* <rostedt@goodmis.org>
+*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>
+--
+REPORTING BUGS
+--------------
+Report bugs to  <linux-trace-devel@vger.kernel.org>
+
+LICENSE
+-------
+libtracefs is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
+
+COPYING
+-------
+Copyright \(C) 2021 VMware, Inc. Free use of this software is granted under
+the terms of the GNU Public License (GPL).
diff --git a/Documentation/libtracefs.txt b/Documentation/libtracefs.txt
index cea21fe..77d053d 100644
--- a/Documentation/libtracefs.txt
+++ b/Documentation/libtracefs.txt
@@ -51,6 +51,16 @@ Trace helper functions:
 	int _tracefs_trace_on_get_fd_(struct tracefs_instance pass:[*]_instance_);
 	int *tracefs_trace_on_fd*(int _fd_);
 	int *tracefs_trace_off_fd*(int _fd_);
+
+Writing data in the trace buffer:
+	int *tracefs_print_init*(struct tracefs_instance pass:[*]_instance_);
+	int *tracefs_printf*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]_fmt_, _..._);
+	int *tracefs_vprintf*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]_fmt_, va_list _ap_);
+	void *tracefs_print_close*(struct tracefs_instance pass:[*]_instance_);
+	int *tracefs_binary_init*(struct tracefs_instance pass:[*]_instance_);
+	int *tracefs_binary_write*(struct tracefs_instance pass:[*]_instance_, void pass:[*]_data_, int _len_);
+	void *tracefs_binary_close*(struct tracefs_instance pass:[*]_instance_);
+
 --
 
 DESCRIPTION
-- 
2.30.2