initial oftree command support

This adds basic device tree command support. So far we can
parse a flat device tree (-p), which also stores the tree
in memory, dump it (-d) and free (-f) the internally stored tree.

The chosen node can be updated with barebox bootargs, no other
device tree manipulation is implemented yet.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 312 insertions, 0 deletions

diff --git a/common/oftree.c b/common/oftree.c
new file mode 100644
index 0000000000..2a2f464204
--- /dev/null
+++ b/common/oftree.c
@@ -0,0 +1,312 @@
+#include <common.h>
+#include <environment.h>
+#include <fdt.h>
+#include <of.h>
+#include <command.h>
+#include <fs.h>
+#include <malloc.h>
+#include <libfdt.h>
+#include <linux/ctype.h>
+#include <asm/byteorder.h>
+#include <errno.h>
+#include <getopt.h>
+#include <init.h>
+
+#define MAX_LEVEL	32		/* how deeply nested we will go */
+
+static int is_printable_string(const void *data, int len)
+{
+	const char *s = data;
+
+	/* zero length is not */
+	if (len == 0)
+		return 0;
+
+	/* must terminate with zero */
+	if (s[len - 1] != '\0')
+		return 0;
+
+	/* printable or a null byte (concatenated strings) */
+	while (((*s == '\0') || isprint(*s)) && (len > 0)) {
+		/*
+		 * If we see a null, there are three possibilities:
+		 * 1) If len == 1, it is the end of the string, printable
+		 * 2) Next character also a null, not printable.
+		 * 3) Next character not a null, continue to check.
+		 */
+		if (s[0] == '\0') {
+			if (len == 1)
+				return 1;
+			if (s[1] == '\0')
+				return 0;
+		}
+		s++;
+		len--;
+	}
+
+	/* Not the null termination, or not done yet: not printable */
+	if (*s != '\0' || (len != 0))
+		return 0;
+
+	return 1;
+}
+
+/*
+ * Print the property in the best format, a heuristic guess.  Print as
+ * a string, concatenated strings, a byte, word, double word, or (if all
+ * else fails) it is printed as a stream of bytes.
+ */
+static void print_data(const void *data, int len)
+{
+	int j;
+
+	/* no data, don't print */
+	if (len == 0)
+		return;
+
+	/*
+	 * It is a string, but it may have multiple strings (embedded '\0's).
+	 */
+	if (is_printable_string(data, len)) {
+		puts("\"");
+		j = 0;
+		while (j < len) {
+			if (j > 0)
+				puts("\", \"");
+			puts(data);
+			j    += strlen(data) + 1;
+			data += strlen(data) + 1;
+		}
+		puts("\"");
+		return;
+	}
+
+	if ((len % 4) == 0) {
+		const u32 *p;
+
+		printf("<");
+		for (j = 0, p = data; j < len/4; j ++)
+			printf("0x%x%s", fdt32_to_cpu(p[j]), j < (len/4 - 1) ? " " : "");
+		printf(">");
+	} else { /* anything else... hexdump */
+		const u8 *s;
+
+		printf("[");
+		for (j = 0, s = data; j < len; j++)
+			printf("%02x%s", s[j], j < len - 1 ? " " : "");
+		printf("]");
+	}
+}
+
+static void printf_indent(int level, const char *fmt, ...)
+{
+	va_list args;
+
+	printf("%*s", level * 8, "");
+
+	va_start (args, fmt);
+	vprintf(fmt, args);
+	va_end (args);
+}
+
+int fdt_print(struct fdt_header *working_fdt, const char *pathp)
+{
+	const void *nodep;	/* property node pointer */
+	int  nodeoffset;	/* node offset from libfdt */
+	int  nextoffset;	/* next node offset from libfdt */
+	uint32_t tag;		/* tag */
+	int  len;		/* length of the property */
+	int  level = 0;		/* keep track of nesting level */
+	const struct fdt_property *fdt_prop;
+
+	nodeoffset = fdt_path_offset(working_fdt, pathp);
+	if (nodeoffset < 0) {
+		/*
+		 * Not found or something else bad happened.
+		 */
+		printf("libfdt fdt_path_offset() returned %s\n",
+			fdt_strerror(nodeoffset));
+		return 1;
+	}
+
+	while (level >= 0) {
+		tag = fdt_next_tag(working_fdt, nodeoffset, &nextoffset);
+		switch (tag) {
+		case FDT_BEGIN_NODE:
+			pathp = fdt_get_name(working_fdt, nodeoffset, NULL);
+			if (pathp == NULL)
+				pathp = "/* NULL pointer error */";
+			if (*pathp == '\0')
+				pathp = "/";	/* root is nameless */
+			printf_indent(level, "%s {\n",pathp);
+			level++;
+			if (level >= MAX_LEVEL) {
+				printf("Nested too deep, aborting.\n");
+				return 1;
+			}
+			break;
+		case FDT_END_NODE:
+			level--;
+			printf_indent(level, "};\n");
+			if (level == 0) {
+				level = -1;		/* exit the loop */
+			}
+			break;
+		case FDT_PROP:
+			fdt_prop = fdt_offset_ptr(working_fdt, nodeoffset,
+					sizeof(*fdt_prop));
+			pathp    = fdt_string(working_fdt,
+					fdt32_to_cpu(fdt_prop->nameoff));
+			len      = fdt32_to_cpu(fdt_prop->len);
+			nodep    = fdt_prop->data;
+			if (len < 0) {
+				printf("libfdt fdt_getprop(): %s\n",
+					fdt_strerror(len));
+				return 1;
+			} else if (len == 0) {
+				/* the property has no value */
+				printf_indent(level, "%s;\n", pathp);
+			} else {
+				printf_indent(level, "%s = ", pathp);
+				print_data(nodep, len);
+				printf(";\n");
+			}
+			break;
+		case FDT_NOP:
+			printf_indent(level, "/* NOP */\n");
+			break;
+		case FDT_END:
+			return 1;
+		default:
+			printf("Unknown tag 0x%08X\n", tag);
+			return 1;
+		}
+		nodeoffset = nextoffset;
+	}
+	return 0;
+}
+
+/**
+ * fdt_find_and_setprop: Find a node and set it's property
+ *
+ * @fdt: ptr to device tree
+ * @node: path of node
+ * @prop: property name
+ * @val: ptr to new value
+ * @len: length of new property value
+ * @create: flag to create the property if it doesn't exist
+ *
+ * Convenience function to directly set a property given the path to the node.
+ */
+int fdt_find_and_setprop(struct fdt_header *fdt, const char *node,
+		const char *prop, const void *val, int len, int create)
+{
+	int nodeoff = fdt_path_offset(fdt, node);
+
+	if (nodeoff < 0)
+		return nodeoff;
+
+	if ((!create) && (fdt_get_property(fdt, nodeoff, prop, 0) == NULL))
+		return 0; /* create flag not set; so exit quietly */
+
+	return fdt_setprop(fdt, nodeoff, prop, val, len);
+}
+
+void do_fixup_by_path(struct fdt_header *fdt, const char *path,
+		const char *prop, const void *val, int len, int create)
+{
+	int rc = fdt_find_and_setprop(fdt, path, prop, val, len, create);
+	if (rc)
+		printf("Unable to update property %s:%s, err=%s\n",
+			path, prop, fdt_strerror(rc));
+}
+
+void do_fixup_by_path_u32(struct fdt_header *fdt, const char *path,
+		const char *prop, u32 val, int create)
+{
+	val = cpu_to_fdt32(val);
+	do_fixup_by_path(fdt, path, prop, &val, sizeof(val), create);
+}
+
+int fdt_get_path_or_create(struct fdt_header *fdt, const char *path)
+{
+	int nodeoffset;
+
+	nodeoffset = fdt_path_offset (fdt, path);
+	if (nodeoffset < 0) {
+		nodeoffset = fdt_add_subnode(fdt, 0, path + 1);
+		if (nodeoffset < 0) {
+			printf("WARNING: could not create %s %s.\n",
+					path, fdt_strerror(nodeoffset));
+                        return -EINVAL;
+                }
+        }
+
+	return nodeoffset;
+}
+
+struct fdt_header *barebox_fdt;
+
+static int of_fixup_bootargs(struct fdt_header *fdt)
+{
+	int nodeoffset;
+	const char *str;
+	int err;
+
+	nodeoffset = fdt_get_path_or_create(fdt, "/chosen");
+	if (nodeoffset < 0)
+		return nodeoffset;
+
+	str = getenv("bootargs");
+	if (str) {
+		err = fdt_setprop(fdt, nodeoffset,
+				"bootargs", str, strlen(str)+1);
+		if (err < 0)
+			printf("WARNING: could not set bootargs %s.\n",
+					fdt_strerror(err));
+        }
+
+	return 0;
+}
+
+static int of_register_bootargs_fixup(void)
+{
+	return of_register_fixup(of_fixup_bootargs);
+}
+late_initcall(of_register_bootargs_fixup);
+
+struct of_fixup {
+	int (*fixup)(struct fdt_header *);
+	struct list_head list;
+};
+
+static LIST_HEAD(of_fixup_list);
+
+int of_register_fixup(int (*fixup)(struct fdt_header *))
+{
+	struct of_fixup *of_fixup = xzalloc(sizeof(*of_fixup));
+
+	of_fixup->fixup = fixup;
+
+	list_add_tail(&of_fixup->list, &of_fixup_list);
+
+	return 0;
+}
+
+struct fdt_header *of_get_fixed_tree(void)
+{
+	struct of_fixup *of_fixup;
+	int ret;
+
+	if (!barebox_fdt)
+		return NULL;
+
+	list_for_each_entry(of_fixup, &of_fixup_list, list) {
+		ret = of_fixup->fixup(barebox_fdt);
+		if (ret)
+			return NULL;
+	}
+
+	return barebox_fdt;
+}
+