035534ed33
The first idea of the CAN FD implementation started with a new struct canfd_frame to be used for both CAN FD frames and legacy CAN frames. The now mainlined implementation supports both CAN frame types simultaneously and distinguishes them only by their required sizes: CAN_MTU and CANFD_MTU. Only the struct canfd_frame contains a flags element which is needed for the additional CAN FD information. As CAN FD implicitly means that the 'Extened Data Length' mode is enabled the formerly defined CANFD_EDL bit became redundant and also confusing as an unset bit would be an error and would always need to be tested. This patch removes the obsolete CANFD_EDL bit and clarifies the documentation for the use of struct canfd_frame and the CAN FD relevant flags. Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
163 lines
5.5 KiB
C
163 lines
5.5 KiB
C
/*
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* linux/can.h
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*
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* Definitions for CAN network layer (socket addr / CAN frame / CAN filter)
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*
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* Authors: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
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* Urs Thuermann <urs.thuermann@volkswagen.de>
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* Copyright (c) 2002-2007 Volkswagen Group Electronic Research
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* All rights reserved.
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*
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*/
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#ifndef CAN_H
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#define CAN_H
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#include <linux/types.h>
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#include <linux/socket.h>
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/* controller area network (CAN) kernel definitions */
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/* special address description flags for the CAN_ID */
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#define CAN_EFF_FLAG 0x80000000U /* EFF/SFF is set in the MSB */
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#define CAN_RTR_FLAG 0x40000000U /* remote transmission request */
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#define CAN_ERR_FLAG 0x20000000U /* error message frame */
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/* valid bits in CAN ID for frame formats */
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#define CAN_SFF_MASK 0x000007FFU /* standard frame format (SFF) */
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#define CAN_EFF_MASK 0x1FFFFFFFU /* extended frame format (EFF) */
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#define CAN_ERR_MASK 0x1FFFFFFFU /* omit EFF, RTR, ERR flags */
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/*
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* Controller Area Network Identifier structure
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*
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* bit 0-28 : CAN identifier (11/29 bit)
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* bit 29 : error message frame flag (0 = data frame, 1 = error message)
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* bit 30 : remote transmission request flag (1 = rtr frame)
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* bit 31 : frame format flag (0 = standard 11 bit, 1 = extended 29 bit)
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*/
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typedef __u32 canid_t;
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#define CAN_SFF_ID_BITS 11
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#define CAN_EFF_ID_BITS 29
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/*
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* Controller Area Network Error Message Frame Mask structure
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*
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* bit 0-28 : error class mask (see include/linux/can/error.h)
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* bit 29-31 : set to zero
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*/
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typedef __u32 can_err_mask_t;
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/* CAN payload length and DLC definitions according to ISO 11898-1 */
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#define CAN_MAX_DLC 8
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#define CAN_MAX_DLEN 8
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/* CAN FD payload length and DLC definitions according to ISO 11898-7 */
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#define CANFD_MAX_DLC 15
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#define CANFD_MAX_DLEN 64
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/**
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* struct can_frame - basic CAN frame structure
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* @can_id: CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition
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* @can_dlc: frame payload length in byte (0 .. 8) aka data length code
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* N.B. the DLC field from ISO 11898-1 Chapter 8.4.2.3 has a 1:1
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* mapping of the 'data length code' to the real payload length
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* @data: CAN frame payload (up to 8 byte)
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*/
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struct can_frame {
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canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */
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__u8 can_dlc; /* frame payload length in byte (0 .. CAN_MAX_DLEN) */
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__u8 data[CAN_MAX_DLEN] __attribute__((aligned(8)));
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};
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/*
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* defined bits for canfd_frame.flags
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*
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* The use of struct canfd_frame implies the Extended Data Length (EDL) bit to
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* be set in the CAN frame bitstream on the wire. The EDL bit switch turns
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* the CAN controllers bitstream processor into the CAN FD mode which creates
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* two new options within the CAN FD frame specification:
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*
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* Bit Rate Switch - to indicate a second bitrate is/was used for the payload
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* Error State Indicator - represents the error state of the transmitting node
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*
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* As the CANFD_ESI bit is internally generated by the transmitting CAN
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* controller only the CANFD_BRS bit is relevant for real CAN controllers when
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* building a CAN FD frame for transmission. Setting the CANFD_ESI bit can make
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* sense for virtual CAN interfaces to test applications with echoed frames.
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*/
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#define CANFD_BRS 0x01 /* bit rate switch (second bitrate for payload data) */
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#define CANFD_ESI 0x02 /* error state indicator of the transmitting node */
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/**
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* struct canfd_frame - CAN flexible data rate frame structure
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* @can_id: CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition
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* @len: frame payload length in byte (0 .. CANFD_MAX_DLEN)
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* @flags: additional flags for CAN FD
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* @__res0: reserved / padding
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* @__res1: reserved / padding
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* @data: CAN FD frame payload (up to CANFD_MAX_DLEN byte)
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*/
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struct canfd_frame {
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canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */
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__u8 len; /* frame payload length in byte */
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__u8 flags; /* additional flags for CAN FD */
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__u8 __res0; /* reserved / padding */
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__u8 __res1; /* reserved / padding */
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__u8 data[CANFD_MAX_DLEN] __attribute__((aligned(8)));
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};
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#define CAN_MTU (sizeof(struct can_frame))
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#define CANFD_MTU (sizeof(struct canfd_frame))
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/* particular protocols of the protocol family PF_CAN */
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#define CAN_RAW 1 /* RAW sockets */
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#define CAN_BCM 2 /* Broadcast Manager */
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#define CAN_TP16 3 /* VAG Transport Protocol v1.6 */
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#define CAN_TP20 4 /* VAG Transport Protocol v2.0 */
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#define CAN_MCNET 5 /* Bosch MCNet */
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#define CAN_ISOTP 6 /* ISO 15765-2 Transport Protocol */
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#define CAN_NPROTO 7
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#define SOL_CAN_BASE 100
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/**
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* struct sockaddr_can - the sockaddr structure for CAN sockets
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* @can_family: address family number AF_CAN.
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* @can_ifindex: CAN network interface index.
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* @can_addr: protocol specific address information
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*/
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struct sockaddr_can {
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__kernel_sa_family_t can_family;
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int can_ifindex;
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union {
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/* transport protocol class address information (e.g. ISOTP) */
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struct { canid_t rx_id, tx_id; } tp;
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/* reserved for future CAN protocols address information */
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} can_addr;
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};
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/**
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* struct can_filter - CAN ID based filter in can_register().
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* @can_id: relevant bits of CAN ID which are not masked out.
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* @can_mask: CAN mask (see description)
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*
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* Description:
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* A filter matches, when
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*
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* <received_can_id> & mask == can_id & mask
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*
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* The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
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* filter for error message frames (CAN_ERR_FLAG bit set in mask).
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*/
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struct can_filter {
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canid_t can_id;
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canid_t can_mask;
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};
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#define CAN_INV_FILTER 0x20000000U /* to be set in can_filter.can_id */
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#endif /* CAN_H */
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