Added support for Multi-Image files that contain a device tree

If a Multi-Image file contains a third image we try to use it as a
device tree.  The device tree image is assumed to be uncompressed in the
image file.  We automatically allocate space for the device tree in memory
and provide an 8k pad to allow more than a reasonable amount of growth.

Additionally, a device tree that was contained in flash will now automatically
get copied to system memory as part of boot.  Previously an error was
reported if one tried to boot a device tree that was in flash.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

common/cmd_bootm.c

@@ -531,6 +531,7 @@ do_bootm_linux (cmd_tbl_t *cmdtp, int flag,
 	image_header_t *hdr = &header;
 #ifdef CONFIG_OF_FLAT_TREE
 	char	*of_flat_tree = NULL;
+	ulong	of_data = 0;
 #endif
 
 	if ((s = getenv ("initrd_high")) != NULL) {
@@ -745,11 +746,8 @@ do_bootm_linux (cmd_tbl_t *cmdtp, int flag,
 
 		if  (*(ulong *)of_flat_tree == OF_DT_HEADER) {
 #ifndef CFG_NO_FLASH
-			if (addr2info((ulong)of_flat_tree) != NULL) {
-				printf ("Cannot modify flat device tree stored in flash\n" \
-					"Copy to memory before using the bootm command\n");
-				return;
-			}
+			if (addr2info((ulong)of_flat_tree) != NULL)
+				of_data = (ulong)of_flat_tree;
 #endif
 		} else if (ntohl(hdr->ih_magic) == IH_MAGIC) {
 			printf("## Flat Device Tree Image at %08lX\n", hdr);
@@ -804,7 +802,39 @@ do_bootm_linux (cmd_tbl_t *cmdtp, int flag,
 		}
 		printf ("   Booting using flat device tree at 0x%x\n",
 				of_flat_tree);
-	} else if(getenv("disable_of") == NULL) {
+	} else if ((hdr->ih_type==IH_TYPE_MULTI) && (len_ptr[1]) && (len_ptr[2])) {
+		u_long tail    = ntohl(len_ptr[0]) % 4;
+		int i;
+
+		/* skip kernel length, initrd length, and terminator */
+		of_data = (ulong)(&len_ptr[3]);
+		/* skip any additional image length fields */
+		for (i=2; len_ptr[i]; ++i)
+			of_data += 4;
+		/* add kernel length, and align */
+		of_data += ntohl(len_ptr[0]);
+		if (tail) {
+			of_data += 4 - tail;
+		}
+
+		/* add initrd length, and align */
+		tail = ntohl(len_ptr[1]) % 4;
+		of_data += ntohl(len_ptr[1]);
+		if (tail) {
+			of_data += 4 - tail;
+		}
+
+		if (((struct boot_param_header *)of_data)->magic != OF_DT_HEADER) {
+			printf ("ERROR: image is not a flat device tree\n");
+			return;
+		}
+
+		if (((struct boot_param_header *)of_data)->totalsize != ntohl(len_ptr[2])) {
+			printf ("ERROR: flat device tree size does not agree with image\n");
+			return;
+		}
+
+	} else if (getenv("disable_of") == NULL) {
 		printf ("ERROR: bootm needs flat device tree as third argument\n");
 		return;
 	}
@@ -900,6 +930,25 @@ do_bootm_linux (cmd_tbl_t *cmdtp, int flag,
 	(*kernel) (kbd, initrd_start, initrd_end, cmd_start, cmd_end);
 
 #else
+	/* move of_flat_tree if needed */
+	if (of_data) {
+		ulong of_start, of_len;
+		of_len = ((struct boot_param_header *)of_data)->totalsize;
+		/* provide extra 8k pad */
+		if (initrd_start)
+			of_start = initrd_start - of_len - 8192;
+		else
+			of_start  = (ulong)kbd - of_len - 8192;
+		of_start &= ~(4096 - 1);	/* align on page */
+		debug ("## device tree at 0x%08lX ... 0x%08lX (len=%ld=0x%lX)\n",
+			of_data, of_data + of_len - 1, of_len, of_len);
+
+		of_flat_tree = (char *)of_start;
+		printf ("   Loading Device Tree to %08lx, end %08lx ... ",
+			of_start, of_start + of_len - 1);
+		memmove ((void *)of_start, (void *)of_data, of_len);
+	}
+
 	ft_setup(of_flat_tree, kbd, initrd_start, initrd_end);
 	/* ft_dump_blob(of_flat_tree); */