Roll CRC16-CCITT into the hash infrastructure

The CRC16-CCITT checksum function is useful for space-constrained
applications (such as obtaining a checksum across a 2KBit or 4KBit
EEPROM) in boot applications. It has not been accessible from boot
scripts until now (due to not having a dedicated command and not being
supported by the hash infrstructure) limiting its applicability
outside of custom commands.

This adds the CRC16-CCITT (poly 0x1021, init 0x0) algorithm to the
list of available hashes and adds a new crc16_ccitt_wd_buf() to make
this possible.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
[trini: Fix building crc16.o for SPL/TPL]
Signed-off-by: Tom Rini <trini@konsulko.com>

1 files changed, 17 insertions, 6 deletions

diff --git a/lib/crc16.c b/lib/crc16.c
index 25bdfd8e72..f46ba727c9 100644
--- a/lib/crc16.c
+++ b/lib/crc16.c
@@ -22,6 +22,11 @@
  *==========================================================================
  */
 
+#ifdef USE_HOSTCC
+#include <arpa/inet.h>
+#else
+#include <common.h>
+#endif
 #include <u-boot/crc.h>
 
 /* Table of CRC constants - implements x^16+x^12+x^5+1 */
@@ -60,14 +65,20 @@ static const uint16_t crc16_tab[] = {
 	0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0,
 };
 
-uint16_t crc16_ccitt(uint16_t crc_start, unsigned char *buf, int len)
+uint16_t crc16_ccitt(uint16_t cksum, const unsigned char *buf, int len)
 {
-	int i;
-	uint16_t cksum;
-
-	cksum = crc_start;
-	for (i = 0;  i < len;  i++)
+	for (int i = 0;  i < len;  i++)
 		cksum = crc16_tab[((cksum>>8) ^ *buf++) & 0xff] ^ (cksum << 8);
 
 	return cksum;
 }
+
+void crc16_ccitt_wd_buf(const uint8_t *in, uint len,
+			uint8_t *out, uint chunk_sz)
+{
+	uint16_t crc;
+
+	crc = crc16_ccitt(0, in, len);
+	crc = htons(crc);
+	memcpy(out, &crc, sizeof(crc));
+}