From 7c9416365c60f150ef8961a2855fafbc7394ad6b Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Wed, 13 Jun 2012 20:04:33 +0200 Subject: [PATCH] canfd: add new data structures and constants - add new struct canfd_frame - check identical element offsets in struct can_frame and struct canfd_frame - new ETH_P_CANFD definition to tag CAN FD skbs correctly - add CAN_MTU and CANFD_MTU definitions for easy frame and mode detection - add CAN[FD]_MAX_[DLC|DLEN] helper constants to remove hard coded values - update existing struct can_frame with helper constants and comments Signed-off-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde --- include/linux/can.h | 59 ++++++++++++++++++++++++++++++++++++---- include/linux/if_ether.h | 3 +- net/can/af_can.c | 7 +++++ 3 files changed, 63 insertions(+), 6 deletions(-) diff --git a/include/linux/can.h b/include/linux/can.h index 17334c09bd9..1a66cf6112a 100644 --- a/include/linux/can.h +++ b/include/linux/can.h @@ -46,18 +46,67 @@ typedef __u32 canid_t; */ typedef __u32 can_err_mask_t; +/* CAN payload length and DLC definitions according to ISO 11898-1 */ +#define CAN_MAX_DLC 8 +#define CAN_MAX_DLEN 8 + +/* CAN FD payload length and DLC definitions according to ISO 11898-7 */ +#define CANFD_MAX_DLC 15 +#define CANFD_MAX_DLEN 64 + /** * struct can_frame - basic CAN frame structure - * @can_id: the CAN ID of the frame and CAN_*_FLAG flags, see above. - * @can_dlc: the data length field of the CAN frame - * @data: the CAN frame payload. + * @can_id: CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition + * @can_dlc: frame payload length in byte (0 .. 8) aka data length code + * N.B. the DLC field from ISO 11898-1 Chapter 8.4.2.3 has a 1:1 + * mapping of the 'data length code' to the real payload length + * @data: CAN frame payload (up to 8 byte) */ struct can_frame { canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */ - __u8 can_dlc; /* data length code: 0 .. 8 */ - __u8 data[8] __attribute__((aligned(8))); + __u8 can_dlc; /* frame payload length in byte (0 .. CAN_MAX_DLEN) */ + __u8 data[CAN_MAX_DLEN] __attribute__((aligned(8))); }; +/* + * defined bits for canfd_frame.flags + * + * As the default for CAN FD should be to support the high data rate in the + * payload section of the frame (HDR) and to support up to 64 byte in the + * data section (EDL) the bits are only set in the non-default case. + * Btw. as long as there's no real implementation for CAN FD network driver + * these bits are only preliminary. + * + * RX: NOHDR/NOEDL - info about received CAN FD frame + * ESI - bit from originating CAN controller + * TX: NOHDR/NOEDL - control per-frame settings if supported by CAN controller + * ESI - bit is set by local CAN controller + */ +#define CANFD_NOHDR 0x01 /* frame without high data rate */ +#define CANFD_NOEDL 0x02 /* frame without extended data length */ +#define CANFD_ESI 0x04 /* error state indicator */ + +/** + * struct canfd_frame - CAN flexible data rate frame structure + * @can_id: CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition + * @len: frame payload length in byte (0 .. CANFD_MAX_DLEN) + * @flags: additional flags for CAN FD + * @__res0: reserved / padding + * @__res1: reserved / padding + * @data: CAN FD frame payload (up to CANFD_MAX_DLEN byte) + */ +struct canfd_frame { + canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */ + __u8 len; /* frame payload length in byte */ + __u8 flags; /* additional flags for CAN FD */ + __u8 __res0; /* reserved / padding */ + __u8 __res1; /* reserved / padding */ + __u8 data[CANFD_MAX_DLEN] __attribute__((aligned(8))); +}; + +#define CAN_MTU (sizeof(struct can_frame)) +#define CANFD_MTU (sizeof(struct canfd_frame)) + /* particular protocols of the protocol family PF_CAN */ #define CAN_RAW 1 /* RAW sockets */ #define CAN_BCM 2 /* Broadcast Manager */ diff --git a/include/linux/if_ether.h b/include/linux/if_ether.h index 56d907a2c80..167ce5b363d 100644 --- a/include/linux/if_ether.h +++ b/include/linux/if_ether.h @@ -105,7 +105,8 @@ #define ETH_P_WAN_PPP 0x0007 /* Dummy type for WAN PPP frames*/ #define ETH_P_PPP_MP 0x0008 /* Dummy type for PPP MP frames */ #define ETH_P_LOCALTALK 0x0009 /* Localtalk pseudo type */ -#define ETH_P_CAN 0x000C /* Controller Area Network */ +#define ETH_P_CAN 0x000C /* CAN: Controller Area Network */ +#define ETH_P_CANFD 0x000D /* CANFD: CAN flexible data rate*/ #define ETH_P_PPPTALK 0x0010 /* Dummy type for Atalk over PPP*/ #define ETH_P_TR_802_2 0x0011 /* 802.2 frames */ #define ETH_P_MOBITEX 0x0015 /* Mobitex (kaz@cafe.net) */ diff --git a/net/can/af_can.c b/net/can/af_can.c index 6efcd37b4bd..c96140a1458 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -41,6 +41,7 @@ */ #include +#include #include #include #include @@ -824,6 +825,12 @@ static struct notifier_block can_netdev_notifier __read_mostly = { static __init int can_init(void) { + /* check for correct padding to be able to use the structs similarly */ + BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) != + offsetof(struct canfd_frame, len) || + offsetof(struct can_frame, data) != + offsetof(struct canfd_frame, data)); + printk(banner); memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list));