From 7db6e3e00c1419fd9c470dc743bdfaf20b197f91 Mon Sep 17 00:00:00 2001
From: Gareth McMullin <gareth@motrr.com>
Date: Sun, 14 Apr 2013 11:28:46 -0700
Subject: [PATCH] Revert "Revert "STM32: Use hardware CRC unit""

This reverts commit 58abbf7fc7686a16ee5bdfacb1241a5adf2921ea.
---
 src/crc32.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/src/crc32.c b/src/crc32.c
index 25cd53b..d5c8732 100644
--- a/src/crc32.c
+++ b/src/crc32.c
@@ -21,6 +21,7 @@
 #include "platform.h"
 #include "target.h"
 
+#if !defined(STM32F1) && !defined(STM32F4)
 static const uint32_t crc32_table[] = {
 	0x00000000, 0x04C11DB7, 0x09823B6E, 0x0D4326D9,
 	0x130476DC, 0x17C56B6B, 0x1A864DB2, 0x1E475005,
@@ -107,4 +108,31 @@ uint32_t generic_crc32(struct target_s *target, uint32_t base, int len)
 	}
 	return crc;
 }
+#else
+#include <libopencm3/stm32/crc.h>
+uint32_t generic_crc32(struct target_s *target, uint32_t base, int len)
+{
+	uint32_t data;
+	uint8_t byte;
 
+        CRC_CR |= CRC_CR_RESET;
+
+	while (len >3) {
+		if (target_mem_read_words(target, &data, base, 1) != 0)
+			return -1;
+
+		CRC_DR = data;
+		base+=4;
+                len -= 4;
+	}
+	while (len--) {
+		if (target_mem_read_bytes(target, &byte, base, 1) != 0)
+			return -1;
+
+		CRC_DR = byte;
+		base++;
+	}
+	return CRC_DR;
+}
+
+#endif