Added CRC8 profiles to handle additional data for checksum generation.

[socketcan-devel.git] / kernel / 2.6 / include / socketcan / can / gw.h

diff --git a/kernel/2.6/include/socketcan/can/gw.h b/kernel/2.6/include/socketcan/can/gw.h
index 2cf3fb7280f63e4d3466536547800ef8379bfaf3..d5d22fa5d47b438af97ff6f4cdddb94b7a53dec5 100644 (file)
--- a/kernel/2.6/include/socketcan/can/gw.h
+++ b/kernel/2.6/include/socketcan/can/gw.h
@@ -87,12 +87,25 @@ struct cgw_csum_crc8 {
        __u8 init_crc_val;
        __u8 final_xor_val;
        __u8 crctab[256];
+       __u8 profile;
+       __u8 profile_data[20];
 } __attribute__ ((packed));
 
 /* length of checksum operation parameters. idx = index in CAN frame data[] */
 #define CGW_CS_XOR_LEN  sizeof(struct cgw_csum_xor)
 #define CGW_CS_CRC8_LEN  sizeof(struct cgw_csum_crc8)
 
+/* CRC8 profiles (compute CRC for additional data elements - see below) */
+enum {
+       CGW_CRC8PRF_UNSPEC,
+       CGW_CRC8PRF_1U8,        /* compute one additional u8 value */
+       CGW_CRC8PRF_16U8,       /* u8 value table indexed by data[1] & 0xF */
+       CGW_CRC8PRF_SFFID_XOR,  /* (can_id & 0xFF) ^ (can_id >> 8 & 0xFF) */
+       __CGW_CRC8PRF_MAX
+};
+
+#define CGW_CRC8PRF_MAX (__CGW_CRC8PRF_MAX - 1)
+
 /*
  * CAN rtnetlink attribute contents in detail
  *
@@ -124,7 +137,7 @@ struct cgw_csum_crc8 {
  *
  * can_frame.data[ result_idx ] = xor
  *
- * CGW_CS_CRC8 (length 261 bytes):
+ * CGW_CS_CRC8 (length 282 bytes):
  * Set a CRC8 value into data[result-idx] using a given 256 byte CRC8 table,
  * a given initial value and a defined input data[start-idx] .. data[end-idx].
  * Finally the result value is XOR'ed with the final_xor_val.
@@ -138,6 +151,13 @@ struct cgw_csum_crc8 {
  *
  * can_frame.data[ result_idx ] = crc ^ final_xor_val
  *
+ * The calculated CRC may contain additional source data elements that can be
+ * defined in the handling of 'checksum profiles' e.g. shown in AUTOSAR specs
+ * like http://www.autosar.org/download/R4.0/AUTOSAR_SWS_E2ELibrary.pdf
+ * E.g. the profile_data[] may contain additional u8 values (called DATA_IDs)
+ * that are used depending on counter values inside the CAN frame data[].
+ * So far only three profiles have been implemented for illustration.
+ *
  * Remark: In general the attribute data is a linear buffer.
  *         Beware of sending unpacked or aligned structs!
  */