// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
/* isotp.c - ISO 15765-2 CAN transport protocol for protocol family CAN
*
* This implementation does not provide ISO-TP specific return values to the
* userspace.
*
* - RX path timeout of data reception leads to -ETIMEDOUT
* - RX path SN mismatch leads to -EILSEQ
* - RX path data reception with wrong padding leads to -EBADMSG
* - TX path flowcontrol reception timeout leads to -ECOMM
* - TX path flowcontrol reception overflow leads to -EMSGSIZE
* - TX path flowcontrol reception with wrong layout/padding leads to -EBADMSG
* - when a transfer (tx) is on the run the next write() blocks until it's done
* - use CAN_ISOTP_WAIT_TX_DONE flag to block the caller until the PDU is sent
* - as we have static buffers the check whether the PDU fits into the buffer
* is done at FF reception time (no support for sending 'wait frames')
* - take care of the tx-queue-len as traffic shaping is still on the TODO list
*
* Copyright (c) 2020 Volkswagen Group Electronic Research
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Volkswagen nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* Alternatively, provided that this notice is retained in full, this
* software may be distributed under the terms of the GNU General
* Public License ("GPL") version 2, in which case the provisions of the
* GPL apply INSTEAD OF those given above.
*
