[POWERPC] Add documentation for the zImage's gunzip convenience functions
This patch adds documenting comments to the gunzip convenience
functions added in commit ad9d2716cfc1cda5a7e0d7bc0db45e3af8a4adbb.
It also removes a stray newline, and an unused global variable.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/boot/gunzip_util.h b/arch/powerpc/boot/gunzip_util.h
index 950f62f..b3dfa6e 100644
--- a/arch/powerpc/boot/gunzip_util.h
+++ b/arch/powerpc/boot/gunzip_util.h
@@ -12,6 +12,22 @@
#include "zlib.h"
+/*
+ * These functions are designed to make life easy for decompressing
+ * kernel images, initrd images or any other gzip compressed image,
+ * particularly if its useful to decompress part of the image (e.g. to
+ * examine headers) before decompressing the remainder.
+ *
+ * To use:
+ * - declare a gunzip_state structure
+ * - use gunzip_start() to initialize the state, associating it
+ * with a stream of compressed data
+ * - use gunzip_partial(), gunzip_exactly() and gunzip_discard()
+ * in any combination to extract pieces of data from the stream
+ * - Finally use gunzip_finish() to extract the tail of the
+ * compressed stream and wind up zlib
+ */
+
/* scratch space for gunzip; 46912 is from zlib_inflate_workspacesize() */
#define GUNZIP_SCRATCH_SIZE 46912
@@ -27,4 +43,3 @@
int gunzip_finish(struct gunzip_state *state, void *dst, int len);
#endif /* _PPC_BOOT_GUNZIP_UTIL_H_ */
-