[PATCH v2 1/2] Documentation: bootconfig: Add EBNF definiton of bootconfig

["Masami Hiramatsu (Google)" <mhiramat@kernel.org>]

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Add the EBNF definition to Documentation/admin-guide/bootconfig.rst
as an additional section to formally define the bootconfig syntax.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 Changes in v2:
  - Move EBNF as a separated section.
---
 Documentation/admin-guide/bootconfig.rst |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index f712758472d5..41bd1ee92395 100644
--- a/Documentation/admin-guide/bootconfig.rst
+++ b/Documentation/admin-guide/bootconfig.rst
@@ -152,6 +152,23 @@ Note that you can NOT put a comment or a newline between value and delimiter
  key = 1 # comment
        ,2
 
+EBNF definition
+===============
+
+The syntax is defined in EBNF as follows::
+
+  Config = { Statement }
+  Statement = [ Key [ Assignment | Block ] | Comment ] ( "\n" | ";" )
+  Assignment = ( "=" | "+=" | ":=" ) ValueList
+  ValueList = [ Value { "," [ { ( Comment | "\n" ) } ] Value } ]
+  Block = "{" { Statement } "}"
+  Key = Word { "." Word }
+  Word = [a-zA-Z0-9_-]+
+  Value = QuotedValue | UnquotedValue
+  QuotedValue = "\"" { any_character_except_double_quote } "\""
+              | "'" { any_character_except_single_quote } "'"
+  UnquotedValue = { any_printable_character_except_delimiters }
+  Comment = "#" { any_character_except_newline }
 
 /proc/bootconfig
 ================