Commit not-finished state of frame length calculation
authorMichal Sojka <sojkam1@fel.cvut.cz>
Wed, 8 Jan 2014 17:28:03 +0000 (18:28 +0100)
committerMichal Sojka <sojkam1@fel.cvut.cz>
Wed, 8 Jan 2014 17:28:03 +0000 (18:28 +0100)
CRC calculation works for both SFF and EFF frames (tested with
osciloscope). Stuff bit calculation needs to be updated.

latester/Makefile.omk
latester/canframelen.c [new file with mode: 0644]
latester/canframelen.h [new file with mode: 0644]
latester/latester.c
latester/test.c [new file with mode: 0644]

index 63db1c2..c9b8e35 100644 (file)
@@ -1,7 +1,7 @@
 # -*- makefile -*-
 
 bin_PROGRAMS += latester vcanbench
-latester_SOURCES = latester.c
+latester_SOURCES = latester.c canframelen.c
 latester_LIBS = rt pthread m talloc popt #ulut
 
 vcanbench_SOURCES = vcanbench.c
@@ -14,3 +14,6 @@ INCLUDES = -DSO_RXQ_OVFL=40 \
 
 bin_PROGRAMS += setpgid
 setpgid_SOURCES = setpgid.c
+
+bin_PROGRAMS += test
+test_SOURCES = test.c canframelen.c
diff --git a/latester/canframelen.c b/latester/canframelen.c
new file mode 100644 (file)
index 0000000..5c9003e
--- /dev/null
@@ -0,0 +1,252 @@
+#include "canframelen.h"
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+#include <string.h>
+#include <assert.h>
+#include <stdio.h>             /* FIXME: remove me */
+
+static void sprint_canframe(char *buf , struct can_frame *cf, int sep) {
+       /* documentation see lib.h */
+
+       int i,offset;
+       int dlc = (cf->can_dlc > 8)? 8 : cf->can_dlc;
+
+       if (cf->can_id & CAN_ERR_FLAG) {
+               sprintf(buf, "%08X#", cf->can_id & (CAN_ERR_MASK|CAN_ERR_FLAG));
+               offset = 9;
+       } else if (cf->can_id & CAN_EFF_FLAG) {
+               sprintf(buf, "%08X#", cf->can_id & CAN_EFF_MASK);
+               offset = 9;
+       } else {
+               sprintf(buf, "%03X#", cf->can_id & CAN_SFF_MASK);
+               offset = 4;
+       }
+
+       if (cf->can_id & CAN_RTR_FLAG) /* there are no ERR frames with RTR */
+               sprintf(buf+offset, "R");
+       else
+               for (i = 0; i < dlc; i++) {
+                       sprintf(buf+offset, "%02X", cf->data[i]);
+                       offset += 2;
+                       if (sep && (i+1 < dlc))
+                               sprintf(buf+offset++, ".");
+               }
+}
+
+/**
+ * Functions and types for CRC checks.
+ *
+ * Generated on Wed Jan  8 15:14:20 2014,
+ * by pycrc v0.8.1, http://www.tty1.net/pycrc/
+ * using the configuration:
+ *    Width        = 15
+ *    Poly         = 0x4599
+ *    XorIn        = 0x0000
+ *    ReflectIn    = False
+ *    XorOut       = 0x0000
+ *    ReflectOut   = False
+ *    Algorithm    = table-driven
+ *****************************************************************************/
+
+typedef uint16_t crc_t;
+
+/**
+ * Static table used for the table_driven implementation.
+ *****************************************************************************/
+static const crc_t crc_table[256] = {
+    0x0000, 0x4599, 0x4eab, 0x0b32, 0x58cf, 0x1d56, 0x1664, 0x53fd, 0x7407, 0x319e, 0x3aac, 0x7f35, 0x2cc8, 0x6951, 0x6263, 0x27fa,
+    0x2d97, 0x680e, 0x633c, 0x26a5, 0x7558, 0x30c1, 0x3bf3, 0x7e6a, 0x5990, 0x1c09, 0x173b, 0x52a2, 0x015f, 0x44c6, 0x4ff4, 0x0a6d,
+    0x5b2e, 0x1eb7, 0x1585, 0x501c, 0x03e1, 0x4678, 0x4d4a, 0x08d3, 0x2f29, 0x6ab0, 0x6182, 0x241b, 0x77e6, 0x327f, 0x394d, 0x7cd4,
+    0x76b9, 0x3320, 0x3812, 0x7d8b, 0x2e76, 0x6bef, 0x60dd, 0x2544, 0x02be, 0x4727, 0x4c15, 0x098c, 0x5a71, 0x1fe8, 0x14da, 0x5143,
+    0x73c5, 0x365c, 0x3d6e, 0x78f7, 0x2b0a, 0x6e93, 0x65a1, 0x2038, 0x07c2, 0x425b, 0x4969, 0x0cf0, 0x5f0d, 0x1a94, 0x11a6, 0x543f,
+    0x5e52, 0x1bcb, 0x10f9, 0x5560, 0x069d, 0x4304, 0x4836, 0x0daf, 0x2a55, 0x6fcc, 0x64fe, 0x2167, 0x729a, 0x3703, 0x3c31, 0x79a8,
+    0x28eb, 0x6d72, 0x6640, 0x23d9, 0x7024, 0x35bd, 0x3e8f, 0x7b16, 0x5cec, 0x1975, 0x1247, 0x57de, 0x0423, 0x41ba, 0x4a88, 0x0f11,
+    0x057c, 0x40e5, 0x4bd7, 0x0e4e, 0x5db3, 0x182a, 0x1318, 0x5681, 0x717b, 0x34e2, 0x3fd0, 0x7a49, 0x29b4, 0x6c2d, 0x671f, 0x2286,
+    0x2213, 0x678a, 0x6cb8, 0x2921, 0x7adc, 0x3f45, 0x3477, 0x71ee, 0x5614, 0x138d, 0x18bf, 0x5d26, 0x0edb, 0x4b42, 0x4070, 0x05e9,
+    0x0f84, 0x4a1d, 0x412f, 0x04b6, 0x574b, 0x12d2, 0x19e0, 0x5c79, 0x7b83, 0x3e1a, 0x3528, 0x70b1, 0x234c, 0x66d5, 0x6de7, 0x287e,
+    0x793d, 0x3ca4, 0x3796, 0x720f, 0x21f2, 0x646b, 0x6f59, 0x2ac0, 0x0d3a, 0x48a3, 0x4391, 0x0608, 0x55f5, 0x106c, 0x1b5e, 0x5ec7,
+    0x54aa, 0x1133, 0x1a01, 0x5f98, 0x0c65, 0x49fc, 0x42ce, 0x0757, 0x20ad, 0x6534, 0x6e06, 0x2b9f, 0x7862, 0x3dfb, 0x36c9, 0x7350,
+    0x51d6, 0x144f, 0x1f7d, 0x5ae4, 0x0919, 0x4c80, 0x47b2, 0x022b, 0x25d1, 0x6048, 0x6b7a, 0x2ee3, 0x7d1e, 0x3887, 0x33b5, 0x762c,
+    0x7c41, 0x39d8, 0x32ea, 0x7773, 0x248e, 0x6117, 0x6a25, 0x2fbc, 0x0846, 0x4ddf, 0x46ed, 0x0374, 0x5089, 0x1510, 0x1e22, 0x5bbb,
+    0x0af8, 0x4f61, 0x4453, 0x01ca, 0x5237, 0x17ae, 0x1c9c, 0x5905, 0x7eff, 0x3b66, 0x3054, 0x75cd, 0x2630, 0x63a9, 0x689b, 0x2d02,
+    0x276f, 0x62f6, 0x69c4, 0x2c5d, 0x7fa0, 0x3a39, 0x310b, 0x7492, 0x5368, 0x16f1, 0x1dc3, 0x585a, 0x0ba7, 0x4e3e, 0x450c, 0x0095
+};
+
+/**
+ * Update the crc value with new data.
+ *
+ * \param crc      The current crc value.
+ * \param data     Pointer to a buffer of \a data_len bytes.
+ * \param data_len Number of bytes in the \a data buffer.
+ * \return         The updated crc value.
+ *****************************************************************************/
+crc_t crc_update_bytewise(crc_t crc, const unsigned char *data, size_t data_len)
+{
+    unsigned int tbl_idx;
+
+    while (data_len--) {
+        tbl_idx = ((crc >> 7) ^ *data) & 0xff;
+        crc = (crc_table[tbl_idx] ^ (crc << 8)) & 0x7fff;
+
+        data++;
+    }
+    return crc & 0x7fff;
+}
+
+/**
+ * Update the crc value with new data.
+ *
+ * \param crc      The current crc value.
+ * \param data     Data value
+ * \param bits    The number of most significant bits in data used for CRC calculation
+ * \return         The updated crc value.
+ *****************************************************************************/
+crc_t crc_update_bitwise(crc_t crc, uint8_t data, size_t bits)
+{
+    uint8_t i;
+    bool bit;
+
+    for (i = 0x80; bits--; i >>= 1) {
+            bit = crc & 0x4000;
+            if (data & i) {
+                   bit = !bit;
+            }
+            crc <<= 1;
+            if (bit) {
+                   crc ^= 0x4599;
+            }
+    }
+    return crc & 0x7fff;
+}
+
+crc_t calc_bitmap_crc(uint8_t *bitmap, unsigned start, unsigned end)
+{
+    crc_t crc = 0;
+
+    if (start%8) {
+           crc = crc_update_bitwise(crc, bitmap[start/8] << (start%8), 8 - start%8);
+           start += 8 - start%8;
+    }
+    crc = crc_update_bytewise(crc, &bitmap[start/8], (end - start) / 8);
+    crc = crc_update_bitwise(crc, bitmap[end/8], end%8);
+    return crc;
+}
+
+void print_bitmap(const char *prefix, uint8_t *bitmap, unsigned start, unsigned end)
+{
+        int i;
+        printf("%s", prefix);
+        for (i = start; i < end; i++)
+                printf("%c", (bitmap[i/8] << (i % 8)) & 0x80 ? '1' : '0');
+        if (*prefix)
+                printf("\n");
+}
+
+unsigned calc_stuff_bits(struct can_frame *frame) {
+       uint8_t bitmap[16];
+       unsigned start = 0, end;
+
+       char received[64];
+       sprint_canframe(received, frame, true);
+       printf("Frame: %s\n", received);
+
+       memset(bitmap, 0, sizeof(bitmap));
+
+       if (frame->can_id & CAN_EFF_FLAG) {
+               //            bit 7      0 7      0 7      0 7      0
+               // bitmap[0-3]   |.sBBBBBB BBBBBSIE EEEEEEEE EEEEEEEE| s = SOF, B = Base ID (11 bits), S = SRR, I = IDE, E = Extended ID (18 bits)
+               // bitmap[4-7]   |ER10DLC4 00000000 11111111 22222222| R = RTR, 0 = r0, 1 = r1, DLC4 = DLC, Data bytes
+               // bitmap[8-11]  |33333333 44444444 55555555 66666666| Data bytes
+               // bitmap[12-15] |77777777 ........ ........ ........| Data bytes
+               bitmap[0] = (frame->can_id & CAN_EFF_MASK) >> 23;
+               bitmap[1] = ((frame->can_id >> 18) & 0x3f) << 3 |
+                           3 << 1                              | /* SRR, IDE */
+                           ((frame->can_id >> 17) & 0x01);
+               bitmap[2] = (frame->can_id >> 9) & 0xff;
+               bitmap[3] = (frame->can_id >> 1) & 0xff;
+               bitmap[4] = (frame->can_id & 0x1) << 7              |
+                           (!!(frame->can_id & CAN_RTR_FLAG)) << 6 |
+                           0 << 4                                  | /* r1, r0 */
+                           frame->can_dlc & 0xf;
+               memcpy(&bitmap[5], &frame->data, frame->can_dlc);
+               start = 1;
+               end = 40 + 8*frame->can_dlc;
+       } else {
+               //           bit 7      0 7      0 7      0 7      0
+               // bitmap[0-3]  |.....sII IIIIIIII IRE0DLC4 00000000| s = SOF, I = ID (11 bits), R = RTR, E = IDE, DLC4 = DLC
+               // bitmap[4-7]  |11111111 22222222 33333333 44444444| Data bytes
+               // bitmap[8-11] |55555555 66666666 77777777 ........| Data bytes
+               bitmap[0] = (frame->can_id & CAN_SFF_MASK) >> 9;
+               bitmap[1] = (frame->can_id >> 1) & 0xff;
+               bitmap[2] = (frame->can_id << 7) & 0xff |
+                           (!!(frame->can_id & CAN_RTR_FLAG)) << 6 |
+                           0 << 4 | /* IDE, r0 */
+                           frame->can_dlc & 0xf;
+               memcpy(&bitmap[3], &frame->data, frame->can_dlc);
+               start = 5;
+               end = 24 + 8*frame->can_dlc;
+       }
+
+       crc_t crc = calc_bitmap_crc(bitmap, start, end);
+       uint16_t crc_be = htons(crc << 1);
+       assert(end%8 == 0);
+       memcpy(bitmap + end/8, &crc_be, 2);
+       print_bitmap("Frame:    ", bitmap, start, end);
+       end += 15;
+       print_bitmap("FrameCRC: ", bitmap, start, end);
+
+       uint8_t mask, ones = 0, basemask = 0xf8;
+       unsigned stuffed = 0;
+       while (start < end) {
+               start++;        /* FIXME: This loop is currently broken!!! */
+               mask = basemask >> (start%32);
+               while (1) {
+                       ones = ones ? mask : 0;
+                       uint32_t chunk = (bitmap[start/32] & mask) ^ ones;
+                       //printf("start=%d  bitmap=0x%08x  mask=0x%08x  ones=0x%08x  chunk=0x%08x\n", start, bitmap[start >> 5], mask, ones, chunk);
+                       if (chunk) {
+                               unsigned change = __builtin_clz(chunk);
+                               start = start & ~0x1f | change;
+                               basemask = 0xf8000000;
+                       } else {
+                               unsigned oldstart = start;
+                               start += __builtin_popcount(mask);
+                               mask = (oldstart & 0x1f) ? basemask << (-oldstart & 0x1f) : 0;
+                               //printf("oldstart=%d  shl=%d  mask=0x%08x\n", oldstart, -oldstart & 0x1f, mask);
+                               if (mask && start < end)
+                                       continue;
+                               if (start <= end && !mask) {
+                                       stuffed++;
+                                       basemask = 0xf0000000;
+                                       //printf("stuffed %d\n", !ones);
+                               }
+                       }
+                       break;
+               }
+               ones = !ones;
+       }
+       //printf ("STUFFED %d BITS\n", stuffed);
+       return stuffed;
+}
+
+unsigned calc_frame_length(struct can_frame *frame)
+{
+       return calc_stuff_bits(frame) +
+               1 +             /* SOF */
+               11 +            /* ID A */
+               ((frame->can_id & CAN_EFF_FLAG) ?
+                1 +            /* SRR */
+                1 +            /* IDE */
+                18 +           /* ID B */
+                1 +            /* RTR */
+                2              /* r1, r0 */
+                :
+                1 +            /* rtr */
+                2) +           /* ide, r0 */
+               4 +             /* dlc */
+               8*frame->can_dlc +
+               15 +            /* CRC */
+               3 +             /* CRC del, ACK, ACK del */
+               7;              /* EOF */
+}
diff --git a/latester/canframelen.h b/latester/canframelen.h
new file mode 100644 (file)
index 0000000..ba8d04a
--- /dev/null
@@ -0,0 +1,8 @@
+#ifndef TXTIME_H
+#define TXTIME_H
+
+#include <linux/can.h>
+
+unsigned calc_frame_length(struct can_frame *frame);
+
+#endif
index 6f4aefd..2e8f6e3 100644 (file)
@@ -1,8 +1,8 @@
-/**************************************************************************/
-/* CAN latency tester                                                     */
-/* Copyright (C) 2010, 2011, 2012, 2013 Michal Sojka, DCE FEE CTU Prague  */
-/* License: GPLv2                                                        */
-/**************************************************************************/
+/*******************************************************************************/
+/* CAN latency tester                                                          */
+/* Copyright (C) 2010, 2011, 2012, 2013, 2014 Michal Sojka, DCE FEE CTU Prague */
+/* License: GPLv2                                                             */
+/*******************************************************************************/
 
 #include <ctype.h>
 #include <errno.h>
@@ -30,6 +30,7 @@
 #include <talloc.h>
 #include <unistd.h>
 
+#include "canframelen.h"
 #include <linux/can.h>
 #include <linux/can/raw.h>
 
@@ -160,153 +161,6 @@ static inline char *tstamp_str(const void *ctx, struct timespec *tstamp)
                               tstamp->tv_sec, tstamp->tv_nsec/1000);
 }
 
-/* Functions and types for CRC checks.
- *
- * Generated on Wed Sep 21 22:30:11 2011,
- * by pycrc v0.7.8, http://www.tty1.net/pycrc/
- * using the configuration:
- *    Width        = 15
- *    Poly         = 0x4599
- *    XorIn        = 0x0000
- *    ReflectIn    = False
- *    XorOut       = 0x0000
- *    ReflectOut   = False
- *    Algorithm    = table-driven
- *****************************************************************************/
-typedef uint16_t crc_t;
-
-static const crc_t crc_table[2] = {
-    0x0000, 0x4599
-};
-
-crc_t crc_update(crc_t crc, uint32_t data, size_t bit_len)
-{
-    unsigned int tbl_idx;
-/*     crc_t bc = crc; */
-/*     uint32_t bd = data; */
-/*     size_t bl = bit_len; */
-
-    while (bit_len--) {
-        tbl_idx = (crc >> 14) ^ (data >> 31);
-        crc = crc_table[tbl_idx & 0x01] ^ (crc << 1);
-       data <<= 1;
-    }
-    crc = crc & 0x7fff;
-/*     printf("crc: 0x%04x -> 0x%04x  data: 0x%08x  len: %d\n", */
-/*        bc, crc, bd, bl); */
-    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 crc << 17;
-}
-
-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));
-       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] =
-                       ((frame->can_id & CAN_EFF_MASK) >> 18) << 25    |
-                       3 << 23                                         |
-                       ((frame->can_id & CAN_EFF_MASK) & 0x3ffff) << 7 |
-                       (!!(frame->can_id & CAN_RTR_FLAG)) << 6         |
-                       0 << 4                                          |
-                       frame->can_dlc & 0xf;
-               memcpy(&bitmap[2], &frame->data, frame->can_dlc);
-               start = 27;
-               end = 64 + 8*frame->can_dlc;
-       } 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;
-               memcpy(&bitmap[1], &frame->data, frame->can_dlc);
-               start = 13;
-               end = 32 + 8*frame->can_dlc;
-       }
-        crc = calc_bitmap_crc(bitmap, start, end);
-       uint32_t crc_be = htons(crc << 17);
-       memcpy((char*)bitmap + end/8, &crc_be, 2); /* end is guaranteed to be divisible by 8 */
-       end += 15;
-
-       while (start < end) {
-               mask = basemask >> (start & 0x1f);
-               while (1) {
-                       ones = ones ? mask : 0;
-                       uint32_t chunk = (bitmap[start >> 5] & mask) ^ ones;
-                       //printf("start=%d  bitmap=0x%08x  mask=0x%08x  ones=0x%08x  chunk=0x%08x\n", start, bitmap[start >> 5], mask, ones, chunk);
-                       if (chunk) {
-                               unsigned change = __builtin_clz(chunk);
-                               start = start & ~0x1f | change;
-                               basemask = 0xf8000000;
-                       } else {
-                               unsigned oldstart = start;
-                               start += __builtin_popcount(mask);
-                               mask = (oldstart & 0x1f) ? basemask << (-oldstart & 0x1f) : 0;
-                               //printf("oldstart=%d  shl=%d  mask=0x%08x\n", oldstart, -oldstart & 0x1f, mask);
-                               if (mask && start < end)
-                                       continue;
-                               if (start <= end && !mask) {
-                                       stuffed++;
-                                       basemask = 0xf0000000;
-                                       //printf("stuffed %d\n", !ones);
-                               }
-                       }
-                       break;
-               }
-               ones = !ones;
-       }
-       //printf ("STUFFED %d BITS\n", stuffed);
-       return stuffed;
-}
-
-unsigned calc_frame_txtime_us(struct can_frame *frame) {
-       return calc_stuff_bits(frame) +
-               1 +             /* SOF */
-               11 +            /* ID A */
-               ((frame->can_id & CAN_EFF_FLAG) ?
-                1 +            /* SRR */
-                1 +            /* IDE */
-                18 +           /* ID B */
-                1 +            /* RTR */
-                2              /* r1, r0 */
-                :
-                1 +            /* rtr */
-                2) +           /* ide, r0 */
-               4 +             /* dlc */
-               8*frame->can_dlc +
-               15 +            /* CRC */
-               3 +             /* CRC del, ACK, ACK del */
-               7;              /* EOF */
-}
-
 void msg_info_print(FILE *f, struct msg_info *mi)
 {
        struct timespec diff;
@@ -402,7 +256,7 @@ static inline void calc_msg_latencies(struct msg_info *mi)
                return;
        }
        mi->lat_measured_us = diff.tv_sec * 1000000 + diff.tv_nsec/1000;
-       mi->tx_time_us = calc_frame_txtime_us(&mi->received);
+       mi->tx_time_us = calc_frame_length(&mi->received);
 }
 
 void set_sched_policy_and_prio(int policy, int rtprio)
diff --git a/latester/test.c b/latester/test.c
new file mode 100644 (file)
index 0000000..214565f
--- /dev/null
@@ -0,0 +1,10 @@
+#include <stdio.h>
+#include "canframelen.h"
+
+int main(int argc, char *argv[])
+{
+       struct can_frame cf = { .can_id = 0x0f111121 | CAN_EFF_FLAG, .can_dlc = 1, .data = { 0x22 } };
+       printf("Length: %u\n", calc_frame_length(&cf));
+
+       return 0;
+}