4 * Copyright (c) 2013, 2014 Czech Technical University in Prague
6 * Author: Michal Sojka <sojkam1@fel.cvut.cz>
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42 * Send feedback to <linux-can@vger.kernel.org>
49 #include <linux/can.h>
52 * Frame length calculation modes.
54 * CFL_WORSTCASE corresponds to *worst* case calculation for
55 * stuff-bits - see (1)-(3) in [1]. The worst case number of bits on
56 * the wire can be calculated as:
58 * (34 + 8n - 1)/4 + 34 + 8n + 13 for SFF frames (11 bit CAN-ID) => 55 + 10n
59 * (54 + 8n - 1)/4 + 54 + 8n + 13 for EFF frames (29 bit CAN-ID) => 80 + 10n
61 * while 'n' is the data length code (number of payload bytes)
63 * [1] "Controller Area Network (CAN) schedulability analysis:
64 * Refuted, revisited and revised", Real-Time Syst (2007)
69 CFL_NO_BITSTUFFING, /* plain bit calculation without bitstuffing */
70 CFL_WORSTCASE, /* worst case estimation - see above */
71 CFL_EXACT, /* exact calculation of stuffed bits based on frame
76 * Calculates the number of bits a frame needs on the wire (including
79 * Mode determines how to deal with stuffed bits.
81 unsigned can_frame_length(struct canfd_frame *frame, enum cfl_mode mode, int mtu);