buildroot/target/cramfs/cramfs-02-endian.patch

--- cramfs-1.1/mkcramfs.c.orig	2005-04-13 05:55:57.000000000 -0600
+++ cramfs-1.1/mkcramfs.c	2005-04-13 16:19:57.000000000 -0600
@@ -117,6 +117,7 @@
 static int opt_squash = 0;
 static char *opt_image = NULL;
 static char *opt_name = NULL;
+static int swap_endian = 0;
 
 static int warn_dev, warn_gid, warn_namelen, warn_skip, warn_size, warn_uid;
 static const char *const memory_exhausted = "memory exhausted";
@@ -155,6 +156,7 @@
 		" -i file    insert a file image into the filesystem (requires >= 2.4.0)\n"
 		" -n name    set name of cramfs filesystem\n"
 		" -p         pad by %d bytes for boot code\n"
+		" -r         reverse endian-ness of filesystem\n"
 		" -s         sort directory entries (old option, ignored)\n"
 		" -v         be more verbose\n"
 		" -z         make explicit holes (requires >= 2.3.39)\n"
@@ -504,6 +506,50 @@
 	return totalsize;
 }
 
+/* routines to swap endianness/bitfields in inode/superblock block data */
+static void fix_inode(struct cramfs_inode *inode)
+{
+#define wswap(x)    (((x)>>24) | (((x)>>8)&0xff00) | (((x)&0xff00)<<8) | (((x)&0xff)<<24))
+	/* attempt #2 */
+	inode->mode = (inode->mode >> 8) | ((inode->mode&0xff)<<8);
+	inode->uid = (inode->uid >> 8) | ((inode->uid&0xff)<<8);
+	inode->size = (inode->size >> 16) | (inode->size&0xff00) |
+		((inode->size&0xff)<<16);
+	((u32*)inode)[2] = wswap(inode->offset | (inode->namelen<<26));
+}
+
+static void fix_offset(struct cramfs_inode *inode, u32 offset)
+{
+	u32 tmp = wswap(((u32*)inode)[2]);
+	((u32*)inode)[2] = wswap((offset >> 2) | (tmp&0xfc000000));
+}
+
+static void fix_block_pointer(u32 *p)
+{
+	*p = wswap(*p);
+}
+
+static void fix_super(struct cramfs_super *super)
+{
+	u32 *p = (u32*)super;
+
+	/* fix superblock fields */
+	p[0] = wswap(p[0]);	/* magic */
+	p[1] = wswap(p[1]);	/* size */
+	p[2] = wswap(p[2]);	/* flags */
+	p[3] = wswap(p[3]);	/* future */
+
+	/* fix filesystem info fields */
+	p = (u32*)&super->fsid;
+	p[0] = wswap(p[0]);	/* crc */
+	p[1] = wswap(p[1]);	/* edition */
+	p[2] = wswap(p[2]);	/* blocks */
+	p[3] = wswap(p[3]);	/* files */
+
+	fix_inode(&super->root);
+#undef wswap
+}
+
 /* Returns sizeof(struct cramfs_super), which includes the root inode. */
 static unsigned int write_superblock(struct entry *root, char *base, int size)
 {
@@ -539,6 +585,7 @@
 	super->root.gid = root->gid;
 	super->root.size = root->size;
 	super->root.offset = offset >> 2;
+	if (swap_endian) fix_super(super);
 
 	return offset;
 }
@@ -553,7 +600,10 @@
 	if (offset >= (1 << (2 + CRAMFS_OFFSET_WIDTH))) {
 		error_msg_and_die("filesystem too big");
 	}
-	inode->offset = (offset >> 2);
+	if (swap_endian)
+		fix_offset(inode, offset);
+	else
+		inode->offset = (offset >> 2);
 }
 
 /*
@@ -638,6 +688,7 @@
 				stack_entries++;
 			}
 			entry = entry->next;
+			if (swap_endian) fix_inode(inode);
 		}
 
 		/*
@@ -734,6 +785,7 @@
 		}
 
 		*(u32 *) (base + offset) = curr;
+		if (swap_endian) fix_block_pointer((u32*)(base + offset));
 		offset += 4;
 	} while (size);
 
@@ -1146,7 +1198,7 @@
 		progname = argv[0];
 
 	/* command line options */
-	while ((c = getopt(argc, argv, "hEe:i:n:psvzD:q")) != EOF) {
+	while ((c = getopt(argc, argv, "hEe:i:n:prsvzD:q")) != EOF) {
 		switch (c) {
 		case 'h':
 			usage(MKFS_OK);
@@ -1174,6 +1226,10 @@
 			opt_pad = PAD_SIZE;
 			fslen_ub += PAD_SIZE;
 			break;
+		case 'r':
+			swap_endian = 1;
+			printf("Swapping filesystem endian-ness\n");
+			break;
 		case 's':
 			/* old option, ignored */
 			break;