Revert "Remove doubled symbols for u2f_sha256 calculations"

This reverts commit dc83516.

firmware/src/atecc508a.c

@@ -36,7 +36,6 @@
 
 #include "bsp.h"
 
-#include "u2f.h"
 
 
 int8_t atecc_send(uint8_t cmd, uint8_t p1, uint16_t p2,
@@ -213,8 +212,46 @@ int8_t atecc_write_eeprom(uint8_t base, uint8_t offset, uint8_t* srcbuf, uint8_t
 
 static uint8_t shabuf[70];
 static uint8_t shaoffset = 0;
+uint8_t SHA_FLAGS = 0;
+uint8_t SHA_HMAC_KEY = 0;
 static struct atecc_response res_digest;
 
+void u2f_sha256_start()
+{
+	shaoffset = 0;
+	atecc_send_recv(ATECC_CMD_SHA,
+			SHA_FLAGS, SHA_HMAC_KEY,NULL,0,
+			shabuf, sizeof(shabuf), NULL);
+	SHA_HMAC_KEY = 0;
+}
+
+
+void u2f_sha256_update(uint8_t * buf, uint8_t len)
+{
+	uint8_t i = 0;
+	watchdog();
+	while(len--)
+	{
+		shabuf[shaoffset++] = *buf++;
+		if (shaoffset == 64)
+		{
+			atecc_send_recv(ATECC_CMD_SHA,
+					ATECC_SHA_UPDATE, 64,shabuf,64,
+					shabuf, sizeof(shabuf), NULL);
+			shaoffset = 0;
+		}
+	}
+}
+
+
+void u2f_sha256_finish()
+{
+	if (SHA_FLAGS == 0) SHA_FLAGS = ATECC_SHA_END;
+	atecc_send_recv(ATECC_CMD_SHA,
+			SHA_FLAGS, shaoffset,shabuf,shaoffset,
+			shabuf, sizeof(shabuf), &res_digest);
+	SHA_FLAGS = 0;
+}
 
 static uint8_t get_signature_length(uint8_t * sig)
 {