fix some misra findings

src/shellmatta_crc.c

@@ -76,12 +76,12 @@ static uint32_t reverse(uint32_t x, uint32_t bits)
  * @param[in]   size            amount of bytes to be processed
  * @return      crc             calculated crc32 value
  */
-static uint32_t crc32Slow(char* data, uint16_t size)
+static uint32_t crc32Slow(const char* data, uint16_t size)
 {
     uint16_t i;
     uint8_t j;
-    uint8_t pivotByte;
     uint32_t polynom = reverse(CRC32_POLYNOM, 32u);
+    uint8_t pivotByte;
 
     /* start with 0xffffffffu */
     uint32_t crcTemp = 0xffffffffu;
@@ -117,7 +117,7 @@ static uint32_t crc32Slow(char* data, uint16_t size)
  * @param[in]   lookupTable     pointer to uint32_t lookup table for crc computation
  * @return      crc             calculated crc32 value
  */
-static uint32_t crc32Fast(char* data, uint16_t size, uint32_t* lookupTable)
+static uint32_t crc32Fast(const char* data, uint16_t size, const uint32_t* lookupTable)
 {
     uint16_t i;
     uint32_t crcTemp = 0xffffffffu;
@@ -139,7 +139,7 @@ static uint32_t crc32Fast(char* data, uint16_t size, uint32_t* lookupTable)
  * @param[in]   size            amount of bytes to be processed
  * @return      crc             calculated crc32 value
  */
-uint32_t crc32Calc(char* data, uint16_t size)
+uint32_t crc32Calc(const char* data, uint16_t size)
 {
     #ifdef  SHELLMATTA_TRANSPORT_CRC_NO_LOOKUP
         return crc32Slow(data, size);

src/shellmatta_crc.h

@@ -20,6 +20,6 @@
 #define CRC32_POLYNOM   0x04c11db7u     /**< crc-32 ethernet 802.3                          */
 #define BITS_PER_BYTE   ((uint8_t)8)    /**< amount of bits per byte; to avoid magic number */
 
-uint32_t crc32Calc(char* data, uint16_t size);
+uint32_t crc32Calc(const char* data, uint16_t size);
 
 #endif /* _SHELLMATTA_CRC_H_ */

src/shellmatta_transport.c

@@ -260,11 +260,11 @@ shellmatta_retCode_t shellmatta_transport_write(shellmatta_transport_layer_t *tr
     shellmatta_transport_packet_t *packet = &transportLayer->outputPacketBuffer;
 
     /* handle data with length bigger than max length */
-    uint32_t piledUpPayload;
     uint32_t processedLength    = 0u;
-    uint32_t splitLength        = 0u;
-    uint32_t splitPayloadLength = 0u;
-    uint32_t restOfPayload      = 0u;
+    uint32_t piledUpPayload;
+    uint32_t splitLength;
+    uint32_t splitPayloadLength;
+    uint32_t restOfPayload;
 
     /* foot-controlled loop to send packets without payload length */
     do