gunzip: add gzwrite routine for extracting compresed images to block device

Initial filesystem images are generally highly compressible.

Add a routine gzwrite that allows gzip-compressed images to be
written to block devices.

Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>
Reviewed-by: Tom Rini <trini@ti.com>

include/common.h

@@ -743,6 +743,45 @@ int gunzip(void *, int, unsigned char *, unsigned long *);
 int zunzip(void *dst, int dstlen, unsigned char *src, unsigned long *lenp,
 						int stoponerr, int offset);
 
+/**
+ * gzwrite progress indicators: defined weak to allow board-specific
+ * overrides:
+ *
+ *	gzwrite_progress_init called on startup
+ *	gzwrite_progress called during decompress/write loop
+ *	gzwrite_progress_finish called at end of loop to
+ *		indicate success (retcode=0) or failure
+ */
+void gzwrite_progress_init(u64 expected_size);
+
+void gzwrite_progress(int iteration,
+		     u64 bytes_written,
+		     u64 total_bytes);
+
+void gzwrite_progress_finish(int retcode,
+			     u64 totalwritten,
+			     u64 totalsize,
+			     u32 expected_crc,
+			     u32 calculated_crc);
+
+/**
+ * decompress and write gzipped image from memory to block device
+ *
+ * @param	src		compressed image address
+ * @param	len		compressed image length in bytes
+ * @param	dev		block device descriptor
+ * @param	szwritebuf	bytes per write (pad to erase size)
+ * @param	startoffs	offset in bytes of first write
+ * @param	szexpected	expected uncompressed length
+ *				may be zero to use gzip trailer
+ *				for files under 4GiB
+ */
+int gzwrite(unsigned char *src, int len,
+	    struct block_dev_desc *dev,
+	    unsigned long szwritebuf,
+	    u64 startoffs,
+	    u64 szexpected);
+
 /* lib/qsort.c */
 void qsort(void *base, size_t nmemb, size_t size,
 	   int(*compar)(const void *, const void *));