Impose log length restrictions

For stm_log() (strings) logging impose a maximum of 1024 bytes of
user data (forced truncation and NULL termination).  For stm_logbin()
(binary) logging split logs larger than 2048 bytes of user data
into individual log packets of up to 2KB of user data per log.

Change-Id: I0be9a1788e54f41a3d675552cb2f81b79a0e5ab8
diff --git a/stm-log.txt b/stm-log.txt
index 78a51f4..c229aa7 100644
--- a/stm-log.txt
+++ b/stm-log.txt
@@ -73,7 +73,7 @@
     parameters are valid.
 
   Parameters:
-    Refer to man pages for printf() for details.
+    Same parameters as printf().  Refer to man pages for printf() for details.
 
   Examples:
     stm_log("event X");
@@ -81,7 +81,12 @@
 
 3.2) stm_logbin(int length, void *data)
   Description:
-    Generate a binary via STM using the default entity/protocol ID and options.
+    Generate a binary log via STM using the default entity/protocol ID and
+    options.
+
+  Parameters:
+    length: Length of binary log data in bytes
+    data:   Binary data
 
 3.3) stm_log_ex(uint8_t     entity_id,
                 uint8_t     proto_id,
@@ -95,10 +100,33 @@
     entity_id: Specify the default entity ID
     proto_id:  Specify the default protocol ID
     options:   Specify the default options
-    ...:       Same as stmlog()
+    ...:       Same as stm_log()
 
 3.4) stm_logbin_ex(uint8_t     entity_id,
                    uint8_t     proto_id,
                    uint32_t    options,
                    int         length,
                    void        *data)
+  Description:
+    Generate a binary log via STM using the specified entity/protocol ID and
+    options.
+
+  Parameters:
+    entity_id: Specify the default entity ID
+    proto_id:  Specify the default protocol ID
+    options:   Specify the default options
+    ...:       Same as stm_logbin()
+
+
+4) Limitations:
+~~~~~~~~~~~~~~~
+
+4.1) stm_log() and stm_log_ex()
+  Log strings via stm_log() or stm_log_ex() are automatically truncated to a
+  maximum of 1024 bytes including the terminating NULL character.
+
+4.2) stm_logbin() and stm_logbin_ex()
+  A single log via stm_logbin() or stm_logbin_ex() that is greater than 2048
+  bytes are broken down into individual packets up to 2048 bytes before
+  sending over the underlying STM transport.  The header is replicated for
+  each log.