1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* Copyright (C) 2020 Oliver Hartkopp <[email protected]> 3 */ 4 5 #ifndef _CAN_LENGTH_H 6 #define _CAN_LENGTH_H 7 8 /* 9 * can_cc_dlc2len(value) - convert a given data length code (dlc) of a 10 * Classical CAN frame into a valid data length of max. 8 bytes. 11 * 12 * To be used in the CAN netdriver receive path to ensure conformance with 13 * ISO 11898-1 Chapter 8.4.2.3 (DLC field) 14 */ 15 #define can_cc_dlc2len(dlc) (min_t(u8, (dlc), CAN_MAX_DLEN)) 16 17 /* helper to get the data length code (DLC) for Classical CAN raw DLC access */ 18 static inline u8 can_get_cc_dlc(const struct can_frame *cf, const u32 ctrlmode) 19 { 20 /* return len8_dlc as dlc value only if all conditions apply */ 21 if ((ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC) && 22 (cf->len == CAN_MAX_DLEN) && 23 (cf->len8_dlc > CAN_MAX_DLEN && cf->len8_dlc <= CAN_MAX_RAW_DLC)) 24 return cf->len8_dlc; 25 26 /* return the payload length as dlc value */ 27 return cf->len; 28 } 29 30 /* helper to set len and len8_dlc value for Classical CAN raw DLC access */ 31 static inline void can_frame_set_cc_len(struct can_frame *cf, const u8 dlc, 32 const u32 ctrlmode) 33 { 34 /* the caller already ensured that dlc is a value from 0 .. 15 */ 35 if (ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC && dlc > CAN_MAX_DLEN) 36 cf->len8_dlc = dlc; 37 38 /* limit the payload length 'len' to CAN_MAX_DLEN */ 39 cf->len = can_cc_dlc2len(dlc); 40 } 41 42 /* get data length from raw data length code (DLC) */ 43 u8 can_fd_dlc2len(u8 dlc); 44 45 /* map the sanitized data length to an appropriate data length code */ 46 u8 can_fd_len2dlc(u8 len); 47 48 #endif /* !_CAN_LENGTH_H */ 49