[PATCH v2] commands: of_property: Extend command usage on external dtb

[Yunus Bas]

The scope of the of_property command is limited to the internal devicetree
only. There is the possibility to add fixtures to postpone the operation
until boot and after the kernel DTB is already loaded, but this does not
cover the case when the property value needs to be phandle adresses
defined in the external DTB, since assigned values are evaluated
immediatly.

This patch extends the of_property-command to use it on external DTB's as
well. In case fixup is not used, the changes will also affect the original
data.

Signed-off-by: Yunus Bas <y.bas at phytec.de>
---
Changes in v2:
- Use %m instead of "%s", strerror(errno)
- Not fixing devicetree anymore before save
---
 commands/of_property.c | 74 ++++++++++++++++++++++++++++++++----------
 1 file changed, 57 insertions(+), 17 deletions(-)

diff --git a/commands/of_property.c b/commands/of_property.c
index 3d5097165..41bb5f71b 100644
--- a/commands/of_property.c
+++ b/commands/of_property.c
@@ -4,6 +4,7 @@
 /* of_property.c - device tree property handling support */
 
 #include <common.h>
+#include <libfile.h>
 #include <environment.h>
 #include <fdt.h>
 #include <of.h>
@@ -18,7 +19,7 @@
 #include <init.h>
 #include <xfuncs.h>
 
-static int of_parse_prop_cells(char * const *newval, int count, char *data, int *len)
+static int of_parse_prop_cells(struct device_node *root, char * const *newval, int count, char *data, int *len)
 {
 	char *cp;
 	unsigned long tmp;	/* holds converted values */
@@ -60,7 +61,7 @@ static int of_parse_prop_cells(char * const *newval, int count, char *data, int
 			str = xzalloc(len + 1);
 			strncpy(str, cp, len);
 
-			n = of_find_node_by_path_or_alias(NULL, str);
+			n = of_find_node_by_path_or_alias(root, str);
 			if (!n)
 				printf("Cannot find node '%s'\n", str);
 
@@ -164,7 +165,7 @@ static int of_parse_prop_string(char * const *newval, int count, char *data, int
  * data: A bytestream to be placed in the property
  * len: The length of the resulting bytestream
  */
-static int of_parse_prop(char * const *newval, int count, char *data, int *len)
+static int of_parse_prop(struct device_node *root, char * const *newval, int count, char *data, int *len)
 {
 	char *newp;		/* temporary newval char pointer */
 
@@ -177,7 +178,7 @@ static int of_parse_prop(char * const *newval, int count, char *data, int *len)
 
 	switch (*newp) {
 	case '<':
-		return of_parse_prop_cells(newval, count, data, len);
+		return of_parse_prop_cells(root, newval, count, data, len);
 	case '[':
 		return of_parse_prop_stream(newval, count, data, len);
 	default:
@@ -302,8 +303,13 @@ static int do_of_property(int argc, char *argv[])
 	int set = 0;
 	int fixup = 0;
 	char *path, *propname;
+	char *dtbfile = NULL;
+	int ret = 0;
+	size_t size;
+	struct fdt_header *fdt = NULL;
+	struct device_node *root = NULL;
 
-	while ((opt = getopt(argc, argv, "dsf")) > 0) {
+	while ((opt = getopt(argc, argv, "dsfe:")) > 0) {
 		switch (opt) {
 		case 'd':
 			delete = 1;
@@ -314,6 +320,9 @@ static int do_of_property(int argc, char *argv[])
 		case 'f':
 			fixup = 1;
 			break;
+		case 'e':
+			dtbfile = optarg;
+			break;
 		default:
 			return COMMAND_ERROR_USAGE;
 		}
@@ -327,8 +336,22 @@ static int do_of_property(int argc, char *argv[])
 
 	debug("path: %s propname: %s\n", path, propname);
 
+	if ( !(set || delete))
+		return COMMAND_ERROR_USAGE;
+
+	if (dtbfile) {
+		fdt = read_file(dtbfile, &size);
+		if (!fdt) {
+			printf("unable to read %s: %m\n", dtbfile);
+			return -errno;
+		}
+
+		root = of_unflatten_dtb(fdt);
+
+		free(fdt);
+	}
+
 	if (set) {
-		int ret;
 		int len;
 		void *data;
 
@@ -340,10 +363,10 @@ static int do_of_property(int argc, char *argv[])
 		if (!data)
 			return -ENOMEM;
 
-		ret = of_parse_prop(&argv[optind + 2], argc - optind - 2, data, &len);
+		ret = of_parse_prop(root, &argv[optind + 2], argc - optind - 2, data, &len);
 		if (ret) {
 			free(data);
-			return ret;
+			goto out;
 		}
 
 		if (fixup) {
@@ -351,21 +374,37 @@ static int do_of_property(int argc, char *argv[])
 			if (ret)
 				free(data);
 		} else {
-			ret = do_of_property_set_now(NULL, path, propname, data, len);
+			ret = do_of_property_set_now(root, path, propname, data, len);
 			free(data);
 		}
 
-		return ret;
-	}
+		if (ret)
+			goto out;
 
-	if (delete) {
+	} else if (delete) {
 		if (fixup)
-			return do_of_property_delete_fixup(path, propname);
+			ret = do_of_property_delete_fixup(path, propname);
 		else
-			return do_of_property_delete_now(NULL, path, propname);
+			ret = do_of_property_delete_now(root, path, propname);
+
+		if (ret)
+			goto out;
+	}
+
+	if (root && !fixup) {
+		fdt = of_flatten_dtb(root);
+
+		ret = write_file(dtbfile, fdt, fdt32_to_cpu(fdt->totalsize));
+
+		free(fdt);
 	}
 
-	return COMMAND_ERROR_USAGE;
+out:
+
+	if (root)
+		of_delete_node(root);
+
+	return ret;
 }
 
 BAREBOX_CMD_HELP_START(of_property)
@@ -373,6 +412,7 @@ BAREBOX_CMD_HELP_TEXT("Options:")
 BAREBOX_CMD_HELP_OPT ("-s",  "set property to value")
 BAREBOX_CMD_HELP_OPT ("-d",  "delete property")
 BAREBOX_CMD_HELP_OPT ("-f",  "set/delete as a fixup (defer the action until booting)")
+BAREBOX_CMD_HELP_OPT ("-e dtb",  "set/delete/fixup from external dtb")
 BAREBOX_CMD_HELP_TEXT("")
 BAREBOX_CMD_HELP_TEXT("Valid formats for values:")
 BAREBOX_CMD_HELP_TEXT("<0x00112233 4 05> - an array of cells. cells not beginning with a digit are")
@@ -384,8 +424,8 @@ BAREBOX_CMD_HELP_END
 BAREBOX_CMD_START(of_property)
 	.cmd		= do_of_property,
 	BAREBOX_CMD_DESC("handle device tree properties")
-	BAREBOX_CMD_OPTS("[-sd] [-f] NODE [PROPERTY] [VALUES]")
+	BAREBOX_CMD_OPTS("[-sd] [-e] [-f] NODE [PROPERTY] [VALUES]")
 	BAREBOX_CMD_GROUP(CMD_GRP_MISC)
-	BAREBOX_CMD_COMPLETE(devicetree_complete)
+	BAREBOX_CMD_COMPLETE(devicetree_file_complete)
 	BAREBOX_CMD_HELP(cmd_of_property_help)
 BAREBOX_CMD_END
-- 
2.30.0