dtc: Add support for variable sized elements

Elements of size 8, 16, 32, and 64 bits are supported.  The new
/bits/ syntax was selected so as to not pollute the reserved
keyword space with uint8/uint16/... type names.

With this patch the following property assignment:

    property = /bits/ 16 <0x1234 0x5678 0x0 0xffff>;

is equivalent to:

    property = <0x12345678 0x0000ffff>;

It is now also possible to directly specify a 64 bit literal in a
cell list, also known as an array using:

    property = /bits/ 64 <0xdeadbeef00000000>;

It is an error to attempt to store a literal into an element that is
too small to hold the literal, and the compiler will generate an
error when it detects this.  For instance:

    property = /bits/ 8 <256>;

Will fail to compile.  It is also an error to attempt to place a
reference in a non 32-bit element.

The documentation has been changed to reflect that the cell list
is now an array of elements that can be of sizes other than the
default 32-bit cell size.

The sized_cells test tests the creation and access of 8, 16, 32,
and 64-bit sized elements.  It also tests that the creation of two
properties, one with 16 bit elements and one with 32 bit elements
result in the same property contents.

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

Documentation/dts-format.txt

@@ -29,18 +29,28 @@ except for properties with empty (zero length) value which have the
 form:
 	[label:] property-name;
 
-Property values may be defined as an array of 32-bit integer cells, as
-NUL-terminated strings, as bytestrings or a combination of these.
+Property values may be defined as an array of 8, 16, 32, or 64-bit integer
+elements, 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 or character literals.
+* Arrays are represented by angle brackets surrounding a space separated list
+  of C-style integers or character literals.  Array elements default to 32-bits
+  in size.  An array of 32-bit elements is also known as a cell list or a list
+  of cells.  A cell being an unsigned 32-bit integer.
 
 	e.g. interrupts = <17 0xc>;
 
-* A 64-bit value is represented with two 32-bit cells.
+* A 64-bit value can be represented with two 32-bit elements.
 
 	e.g. clock-frequency = <0x00000001 0x00000000>;
 
+* The storage size of an element can be changed using the /bits/ prefix.  The
+  /bits/ prefix allows for the creation of 8, 16, 32, and 64-bit elements.
+  The resulting array will not be padded to a multiple of the default 32-bit
+  element size.
+
+	e.g. interrupts = /bits/ 8 <17 0xc>;
+	e.g. clock-frequency = /bits/ 64 <0x0000000100000000>;
+
 * A NUL-terminated string value is represented using double quotes
   (the property value is considered to include the terminating NUL
   character).
@@ -59,19 +69,20 @@ NUL-terminated strings, as bytestrings or a combination of these.
 	e.g. compatible = "ns16550", "ns8250";
 	     example = <0xf00f0000 19>, "a strange property format";
 
-* In a cell array a reference to another node will be expanded to that
-  node's phandle.  References may by '&' followed by a node's label:
+* In an array a reference to another node will be expanded to that node's
+  phandle.  References may by '&' followed by a node's label:
 	e.g. interrupt-parent = < &mpic >;
   or they may be '&' followed by a node's full path in braces:
 	e.g. interrupt-parent = < &{/soc/interrupt-controller@40000} >;
+  References are only permitted in arrays that have an element size of
+  32-bits.
 
-* Outside a cell array, a reference to another node will be expanded
-  to that node's full path.
+* Outside an array, a reference to another node will be expanded to that
+  node's full path.
 	e.g. ethernet0 = &EMAC0;
 
 * Labels may also appear before or after any component of a property
-  value, or between cells of a cell array, or between bytes of a
-  bytestring.
+  value, or between elements of an array, or between bytes of a bytestring.
 	e.g. reg = reglabel: <0 sizelabel: 0x1000000>;
 	e.g. prop = [ab cd ef byte4: 00 ff fe];
 	e.g. str = start: "string value" end: ;
@@ -108,3 +119,4 @@ Version 1 DTS files have the overall layout:
 
 	-- David Gibson <david@gibson.dropbear.id.au>
 	-- Yoder Stuart <stuart.yoder@freescale.com>
+	-- Anton Staaf <robotboy@chromium.org>

dtc-lexer.l

@@ -97,6 +97,12 @@ static int pop_input_file(void);
 			return DT_MEMRESERVE;
 		}
 
+<*>"/bits/"	{
+			DPRINT("Keyword: /bits/\n");
+			BEGIN_DEFAULT();
+			return DT_BITS;
+		}
+
 <*>{LABEL}:	{
 			DPRINT("Label: %s\n", yytext);
 			yylval.labelref = xstrdup(yytext);

dtc-parser.y

@@ -45,8 +45,12 @@ static unsigned char eval_char_literal(const char *s);
 	uint8_t byte;
 	struct data data;
 
+	struct {
+		struct data	data;
+		int		bits;
+	} array;
+
 	uint64_t addr;
-	cell_t cell;
 	struct property *prop;
 	struct property *proplist;
 	struct node *node;
@@ -56,6 +60,7 @@ static unsigned char eval_char_literal(const char *s);
 
 %token DT_V1
 %token DT_MEMRESERVE
+%token DT_BITS
 %token <propnodename> DT_PROPNODENAME
 %token <literal> DT_LITERAL
 %token <literal> DT_CHAR_LITERAL
@@ -71,8 +76,7 @@ static unsigned char eval_char_literal(const char *s);
 %type <re> memreserve
 %type <re> memreserves
 %type <addr> addr
-%type <data> celllist
-%type <cell> cellval
+%type <array> arrayprefix
 %type <data> bytestring
 %type <prop> propdef
 %type <proplist> proplist
@@ -182,9 +186,9 @@ propdata:
 		{
 			$$ = data_merge($1, $2);
 		}
-	| propdataprefix '<' celllist '>'
+	| propdataprefix arrayprefix '>'
 		{
-			$$ = data_merge($1, $3);
+			$$ = data_merge($1, $2.data);
 		}
 	| propdataprefix '[' bytestring ']'
 		{
@@ -242,34 +246,56 @@ propdataprefix:
 		}
 	;
 
-celllist:
-	  /* empty */
+arrayprefix:
+	DT_BITS DT_LITERAL '<'
 		{
-			$$ = empty_data;
+			$$.data = empty_data;
+			$$.bits = eval_literal($2, 0, 7);
+
+			if (($$.bits !=  8) &&
+			    ($$.bits != 16) &&
+			    ($$.bits != 32) &&
+			    ($$.bits != 64))
+			{
+				print_error("Only 8, 16, 32 and 64-bit elements"
+					    " are currently supported");
+				$$.bits = 32;
+			}
 		}
-	| celllist cellval
+	| '<'
 		{
-			$$ = data_append_cell($1, $2);
+			$$.data = empty_data;
+			$$.bits = 32;
 		}
-	| celllist DT_REF
+	| arrayprefix DT_LITERAL
 		{
-			$$ = data_append_cell(data_add_marker($1, REF_PHANDLE,
-							      $2), -1);
+			uint64_t val = eval_literal($2, 0, $1.bits);
+
+			$$.data = data_append_integer($1.data, val, $1.bits);
 		}
-	| celllist DT_LABEL
+	| arrayprefix DT_CHAR_LITERAL
 		{
-			$$ = data_add_marker($1, LABEL, $2);
-		}
-	;
+			uint64_t val = eval_char_literal($2);
 
-cellval:
-	  DT_LITERAL
+			$$.data = data_append_integer($1.data, val, $1.bits);
+		}
+	| arrayprefix DT_REF
 		{
-			$$ = eval_literal($1, 0, 32);
+			uint64_t val = ~0ULL >> (64 - $1.bits);
+
+			if ($1.bits == 32)
+				$1.data = data_add_marker($1.data,
+							  REF_PHANDLE,
+							  $2);
+			else
+				print_error("References are only allowed in "
+					    "arrays with 32-bit elements.");
+
+			$$.data = data_append_integer($1.data, val, $1.bits);
 		}
-	| DT_CHAR_LITERAL
+	| arrayprefix DT_LABEL
 		{
-			$$ = eval_char_literal($1);
+			$$.data = data_add_marker($1.data, LABEL, $2);
 		}
 	;
 

tests/.gitignore

@@ -40,6 +40,7 @@
 /set_name
 /setprop
 /setprop_inplace
+/sized_cells
 /string_escapes
 /subnode_offset
 /supernode_atdepth_offset

tests/Makefile.tests

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

tests/run_tests.sh

@@ -209,6 +209,9 @@ dtc_tests () {
     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_sized_cells.test.dtb sized_cells.dts
+    run_test sized_cells dtc_sized_cells.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/sized_cells.c

@@ -0,0 +1,84 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ *	Testcase for variable sized cells 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"
+
+static void check_compare_properties(void *fdt,
+				     char const *name_one,
+				     char const *name_two)
+{
+	const void *propval;
+	int proplen;
+
+	propval = fdt_getprop(fdt, 0, name_one, &proplen);
+
+	if (!propval)
+		FAIL("fdt_getprop(\"%s\"): %s",
+		     name_one,
+		     fdt_strerror(proplen));
+
+	check_getprop(fdt, 0, name_two, proplen, propval);
+}
+
+int main(int argc, char *argv[])
+{
+	void *fdt;
+	uint8_t expected_8[6] = {TEST_CHAR1,
+				 TEST_CHAR2,
+				 TEST_CHAR3,
+				 TEST_CHAR4,
+				 TEST_CHAR5,
+				 TEST_VALUE_1 >> 24};
+	uint16_t expected_16[6];
+	uint32_t expected_32[6];
+	uint64_t expected_64[6];
+	int i;
+
+	for (i = 0; i < 5; ++i) {
+		expected_16[i] = cpu_to_fdt16(expected_8[i]);
+		expected_32[i] = cpu_to_fdt32(expected_8[i]);
+		expected_64[i] = cpu_to_fdt64(expected_8[i]);
+	}
+
+	expected_16[5] = cpu_to_fdt16(TEST_VALUE_1 >> 16);
+	expected_32[5] = cpu_to_fdt32(TEST_VALUE_1);
+	expected_64[5] = cpu_to_fdt64(TEST_ADDR_1);
+
+	test_init(argc, argv);
+	fdt = load_blob_arg(argc, argv);
+
+	check_getprop(fdt, 0, "cells-8b", sizeof(expected_8), expected_8);
+	check_getprop(fdt, 0, "cells-16b", sizeof(expected_16), expected_16);
+	check_getprop(fdt, 0, "cells-32b", sizeof(expected_32), expected_32);
+	check_getprop(fdt, 0, "cells-64b", sizeof(expected_64), expected_64);
+
+	check_compare_properties(fdt, "cells-one-16b", "cells-one-32b");
+
+	PASS();
+}

tests/sized_cells.dts

@@ -0,0 +1,11 @@
+/dts-v1/;
+
+/ {
+	cells-8b = /bits/ 8 <'\r' 'b' '\0' '\'' '\xff' 0xde>;
+	cells-16b = /bits/ 16 <'\r' 'b' '\0' '\'' '\xff' 0xdead>;
+	cells-32b = /bits/ 32 <'\r' 'b' '\0' '\'' '\xff' 0xdeadbeef>;
+	cells-64b = /bits/ 64 <'\r' 'b' '\0' '\'' '\xff' 0xdeadbeef00000000>;
+
+	cells-one-16b = /bits/ 16 <0x1234 0x5678 0x0 0xffff>;
+	cells-one-32b = <0x12345678 0x0000ffff>;
+};