X-Git-Url: http://rtime.felk.cvut.cz/gitweb/can-benchmark.git/blobdiff_plain/1123f260ffaa253d3469c34afb00a9f595aefea8..467e092776691683b297e1328281cded11717298:/latester/latester.c

diff --git a/latester/latester.c b/latester/latester.c
index 140811f..0906760 100644
--- a/latester/latester.c
+++ b/latester/latester.c
@@ -1,6 +1,6 @@
 /**************************************************************************/
 /* CAN latency tester                                                     */
-/* Copyright (C) 2010, 2011, 2012 Michal Sojka, DCE FEE CTU Prague        */
+/* Copyright (C) 2010, 2011, 2012, 2013 Michal Sojka, DCE FEE CTU Prague  */
 /* License: GPLv2     	     	    	    				  */
 /**************************************************************************/
 
@@ -197,20 +197,51 @@ crc_t crc_update(crc_t crc, uint32_t data, size_t bit_len)
     return crc;
 }
 
+uint32_t calc_bitmap_crc(uint32_t *bitmap, unsigned start, unsigned end)
+{
+    crc_t crc = 0;
+    crc = crc_update(crc, bitmap[0] << start, 32 - start);
+    crc = crc_update(crc, bitmap[1], 32);
+    crc = crc_update(crc, bitmap[2], end - 64 > 32 ? 32 : end - 64); /* FIXME: This seems to be broken for end < 64 */
+    crc = crc_update(crc, bitmap[3], end > 96 ? end - 96 : 0);
+    return (uint32_t)htons(crc << 17);
+}
+
+void write_crc_to_bitmap(uint32_t crc, uint32_t *bitmap, struct can_frame *frame)
+{
+    unsigned index = frame->can_id & CAN_EFF_FLAG ? 2 : 1;
+    if (frame->can_dlc < 4)
+        bitmap[index] |= crc >> (frame->can_dlc*8);
+    if (frame->can_dlc == 3)
+        bitmap[index + 1] |= crc << 8;
+    if (frame->can_dlc >= 4 && frame->can_dlc < 8)
+    {
+        bitmap[index + 1] |= crc >> (frame->can_dlc*8);
+        if (frame->can_dlc == 7)
+            bitmap[index + 2] = crc << 8;
+    }
+    else if (frame->can_dlc == 8)
+        bitmap[index + 2] = crc;
+}
+
 unsigned calc_stuff_bits(struct can_frame *frame) {
 	uint32_t bitmap[4];
 	unsigned start = 0, end;
 	uint32_t mask, ones = 0, basemask = 0xf8000000;
 	unsigned stuffed = 0;
 	memset(bitmap, 0, sizeof(bitmap));
-	crc_t crc = 0;
-	uint32_t crcx;
+	uint32_t crc;
 
 /* 	char received[64]; */
 /* 	sprint_canframe(received, frame, true); */
 /* 	printf("Frame: %s\n", received); */
 	
 	if (frame->can_id & CAN_EFF_FLAG) {
+		// bit 31                              0
+		// [0] |...........................sBBBB| s = SOF, B = Base ID (11 bits)
+		// [1] |BBBBBBBSIEEEEEEEEEEEEEEEEEER10DLC4| S = SRR, I = IDE, E = Extended ID (18 bits), DLC4 = DLC
+		// [2] |00000000111111112222222233333333| Data bytes, MSB first
+		// [3] |44444444555555556666666677777777|
 		bitmap[0] =
 			((frame->can_id & CAN_EFF_MASK) >> 25);
 		bitmap[1] =
@@ -220,33 +251,27 @@ unsigned calc_stuff_bits(struct can_frame *frame) {
 			(!!(frame->can_id & CAN_RTR_FLAG)) << 6		|
 			0 << 4						|
 			frame->can_dlc & 0xf;
-		bitmap[2] = htonl(((uint32_t*)frame->data)[0]);
-		bitmap[3] = htonl(((uint32_t*)frame->data)[1]);
+		memcpy(&bitmap[2], &frame->data, frame->can_dlc);
 		start = 27;
 		end = 64 + 8*frame->can_dlc;
-		crc = crc_update(crc, bitmap[0] << start, 32-start);
-		crc = crc_update(crc, bitmap[1], 32);
-		crc = crc_update(crc, bitmap[2], end - 64 > 32 ? 32 : end - 64);
-		crc = crc_update(crc, bitmap[3], end > 96 ? end - 96 : 0);
-		crcx = (uint32_t)htons(crc) << 17;
-		if (frame->can_dlc < 4)
-			bitmap[2] |= crcx >> (frame->can_dlc*8);
-		if (frame->can_dlc = 3)
-			bitmap[3] |= crcx << 8;
-		if (frame->can_dlc >= 4)
-			bitmap[3] |= crcx >> (frame->can_dlc*8);
 	} else {
+		// bit 31                              0
+		// [0] |.............sIIIIIIIIIIIRE0DLC4| s = SOF, I = ID (11 bits), R = RTR, E = IDE, DLC4 = DLC
+		// [1] |00000000111111112222222233333333| Data bytes, MSB first
+		// [2] |44444444555555556666666677777777|
 		bitmap[0] =
 			(frame->can_id << 7) |
 			(!!(frame->can_id & CAN_RTR_FLAG)) << 6 |
 			0 << 4 					|
 			frame->can_dlc & 0xf;
-		bitmap[1] = htonl(((uint32_t*)frame->data)[0]);
-		bitmap[2] = htonl(((uint32_t*)frame->data)[1]);
+		memcpy(&bitmap[1], &frame->data, frame->can_dlc);
 		start = 13;
 		end = 32 + 8*frame->can_dlc;
 	}
-	/* TODO: Calc stuff bits in CRC */
+        crc = calc_bitmap_crc(bitmap, start, end);
+        write_crc_to_bitmap(crc, bitmap, frame);
+        end += 15;
+
 	while (start < end) {
 		mask = basemask >> (start & 0x1f);
 		while (1) {