mkimage : Split out and clean pbl_crc32 for use by other image types

[karo-tx-uboot.git] / tools / pbl_crc32.c

diff --git a/tools/pbl_crc32.c b/tools/pbl_crc32.c
new file mode 100644 (file)
index 0000000..6e6735a
--- /dev/null
+++ b/tools/pbl_crc32.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2012 Freescale Semiconductor, Inc.
+ *
+ * Cleaned up and refactored by Charles Manning.
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+#include "pblimage.h"
+
+static uint32_t crc_table[256];
+static int crc_table_valid;
+
+static void make_crc_table(void)
+{
+       uint32_t mask;
+       int i, j;
+       uint32_t poly; /* polynomial exclusive-or pattern */
+
+       if (crc_table_valid)
+               return;
+
+       /*
+        * the polynomial used by PBL is 1 + x1 + x2 + x4 + x5 + x7 + x8 + x10
+        * + x11 + x12 + x16 + x22 + x23 + x26 + x32.
+        */
+       poly = 0x04c11db7;
+
+       for (i = 0; i < 256; i++) {
+               mask = i << 24;
+               for (j = 0; j < 8; j++) {
+                       if (mask & 0x80000000)
+                               mask = (mask << 1) ^ poly;
+                       else
+                               mask <<= 1;
+               }
+               crc_table[i] = mask;
+       }
+
+       crc_table_valid = 1;
+}
+
+uint32_t pbl_crc32(uint32_t in_crc, const char *buf, uint32_t len)
+{
+       uint32_t crc32_val;
+       int i;
+
+       make_crc_table();
+
+       crc32_val = ~in_crc;
+
+       for (i = 0; i < len; i++)
+               crc32_val = (crc32_val << 8) ^
+                       crc_table[(crc32_val >> 24) ^ (*buf++ & 0xff)];
+
+       return crc32_val;
+}