dtc: Support character literals in cell lists

With this patch the following property assignment:

    property = <0x12345678 'a' '\r' 100>;

is equivalent to:

    property = <0x12345678 0x00000061 0x0000000D 0x00000064>

Signed-off-by: Anton Staaf <robotboy@chromium.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>

Documentation/dts-format.txt

@@ -33,7 +33,7 @@ Property values may be defined as an array of 32-bit integer cells, as
 NUL-terminated strings, as bytestrings or a combination of these.
 
 * Arrays of cells are represented by angle brackets surrounding a
-  space separated list of C-style integers
+  space separated list of C-style integers or character literals.
 
 	e.g. interrupts = <17 0xc>;
 

dtc-lexer.l

@@ -29,6 +29,7 @@ PROPNODECHAR	[a-zA-Z0-9,._+*#?@-]
 PATHCHAR	({PROPNODECHAR}|[/])
 LABEL		[a-zA-Z_][a-zA-Z0-9_]*
 STRING		\"([^\\"]|\\.)*\"
+CHAR_LITERAL	'([^']|\\')*'
 WS		[[:space:]]
 COMMENT		"/*"([^*]|\*+[^*/])*\*+"/"
 LINECOMMENT	"//".*\n
@@ -109,6 +110,13 @@ static int pop_input_file(void);
 			return DT_LITERAL;
 		}
 
+<*>{CHAR_LITERAL}	{
+			yytext[yyleng-1] = '\0';
+			yylval.literal = xstrdup(yytext+1);
+			DPRINT("Character literal: %s\n", yylval.literal);
+			return DT_CHAR_LITERAL;
+		}
+
 <*>\&{LABEL}	{	/* label reference */
 			DPRINT("Ref: %s\n", yytext+1);
 			yylval.labelref = xstrdup(yytext+1);

dtc-parser.y

@@ -34,6 +34,7 @@ extern struct boot_info *the_boot_info;
 extern int treesource_error;
 
 static unsigned long long eval_literal(const char *s, int base, int bits);
+static unsigned char eval_char_literal(const char *s);
 %}
 
 %union {
@@ -57,6 +58,7 @@ static unsigned long long eval_literal(const char *s, int base, int bits);
 %token DT_MEMRESERVE
 %token <propnodename> DT_PROPNODENAME
 %token <literal> DT_LITERAL
+%token <literal> DT_CHAR_LITERAL
 %token <cbase> DT_BASE
 %token <byte> DT_BYTE
 %token <data> DT_STRING
@@ -265,6 +267,10 @@ cellval:
 		{
 			$$ = eval_literal($1, 0, 32);
 		}
+	| DT_CHAR_LITERAL
+		{
+			$$ = eval_char_literal($1);
+		}
 	;
 
 bytestring:
@@ -343,3 +349,29 @@ static unsigned long long eval_literal(const char *s, int base, int bits)
 		print_error("bad literal");
 	return val;
 }
+
+static unsigned char eval_char_literal(const char *s)
+{
+	int i = 1;
+	char c = s[0];
+
+	if (c == '\0')
+	{
+		print_error("empty character literal");
+		return 0;
+	}
+
+	/*
+	 * If the first character in the character literal is a \ then process
+	 * the remaining characters as an escape encoding. If the first
+	 * character is neither an escape or a terminator it should be the only
+	 * character in the literal and will be returned.
+	 */
+	if (c == '\\')
+		c = get_escape_char(s, &i);
+
+	if (s[i] != '\0')
+		print_error("malformed character literal");
+
+	return c;
+}

tests/.gitignore

@@ -4,6 +4,7 @@
 /add_subnode_with_nops
 /asm_tree_dump
 /boot-cpuid
+/char_literal
 /del_node
 /del_property
 /dtbs_equal_ordered

tests/Makefile.tests

@@ -5,6 +5,7 @@ LIB_TESTS_L = get_mem_rsv \
 	node_offset_by_prop_value node_offset_by_phandle \
 	node_check_compatible node_offset_by_compatible \
 	get_alias \
+	char_literal \
 	notfound \
 	setprop_inplace nop_property nop_node \
 	sw_tree1 \

tests/char_literal.c

@@ -0,0 +1,50 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ *	Testcase for character literals in dtc
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ * Copyright (C) 2011 The Chromium Authors. All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "tests.h"
+#include "testdata.h"
+
+int main(int argc, char *argv[])
+{
+	void *fdt;
+	uint32_t expected_cells[5];
+
+	expected_cells[0] = cpu_to_fdt32((unsigned char)TEST_CHAR1);
+	expected_cells[1] = cpu_to_fdt32((unsigned char)TEST_CHAR2);
+	expected_cells[2] = cpu_to_fdt32((unsigned char)TEST_CHAR3);
+	expected_cells[3] = cpu_to_fdt32((unsigned char)TEST_CHAR4);
+	expected_cells[4] = cpu_to_fdt32((unsigned char)TEST_CHAR5);
+
+	test_init(argc, argv);
+	fdt = load_blob_arg(argc, argv);
+
+	check_getprop(fdt, 0, "char-literal-cells",
+		      sizeof(expected_cells), expected_cells);
+
+	PASS();
+}

tests/char_literal.dts

@@ -0,0 +1,5 @@
+/dts-v1/;
+
+/ {
+	char-literal-cells = <'\r' 'b' '\0' '\'' '\xff'>;
+};

tests/run_tests.sh

@@ -206,6 +206,9 @@ dtc_tests () {
     run_dtc_test -I dts -O dtb -o dtc_escapes.test.dtb escapes.dts
     run_test string_escapes dtc_escapes.test.dtb
 
+    run_dtc_test -I dts -O dtb -o dtc_char_literal.test.dtb char_literal.dts
+    run_test char_literal dtc_char_literal.test.dtb
+
     run_dtc_test -I dts -O dtb -o dtc_extra-terminating-null.test.dtb extra-terminating-null.dts
     run_test extra-terminating-null dtc_extra-terminating-null.test.dtb
 

tests/testdata.h

@@ -19,6 +19,12 @@
 #define TEST_STRING_2	"nastystring: \a\b\t\n\v\f\r\\\""
 #define TEST_STRING_3	"\xde\xad\xbe\xef"
 
+#define TEST_CHAR1	'\r'
+#define TEST_CHAR2	'b'
+#define TEST_CHAR3	'\0'
+#define TEST_CHAR4	'\''
+#define TEST_CHAR5	'\xff'
+
 #ifndef __ASSEMBLY__
 extern struct fdt_header _test_tree1;
 extern struct fdt_header _truncated_property;