mi4: replace chksum_crc32 with crc_32r

This uses an equivalent algorithm but with a different initial value
than we normally use (all bits off vs all bits on). Use the new crc_32r
to replace the original MI4 crc32 implementation.

This frees up some extra space on mi4 targets which gives us more
room on a few very space constrained targets (sansa c200/e200, etc).

Change-Id: Iaaac3ae353b30566156b1404cbf31ca32926203d

1 files changed, 2 insertions, 3 deletions

diff --git a/firmware/target/arm/pp/mi4-loader.c b/firmware/target/arm/pp/mi4-loader.c
index 31b0065888..0104496e9d 100644
--- a/firmware/target/arm/pp/mi4-loader.c
+++ b/firmware/target/arm/pp/mi4-loader.c
@@ -27,12 +27,11 @@
 #include "config.h"
 #include "mi4-loader.h"
 #include "loader_strerror.h"
-#include "crc32-mi4.h"
+#include "crc32.h"
 #include "file.h"
 #if defined(HAVE_BOOTDATA)
 #include "system.h"
 #include "bootdata.h"
-#include "crc32.h"
 
 /* Write bootdata into location in FIRMWARE marked by magic header
  * Assumes buffer is already loaded with the firmware image
@@ -293,7 +292,7 @@ static int load_mi4_filename(unsigned char* buf,
         return EREAD_IMAGE_FAILED;
 
     /* Check CRC32 to see if we have a valid file */
-    sum = chksum_crc32 (buf, mi4header.mi4size - MI4_HEADER_SIZE);
+    sum = crc_32r (buf, mi4header.mi4size - MI4_HEADER_SIZE, 0);
 
     if(sum != mi4header.crc32)
         return EBAD_CHKSUM;