| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* Copyright (C) 2020 Oliver Hartkopp <socketcan@hartkopp.net> |
| * Copyright (C) 2020 Marc Kleine-Budde <kernel@pengutronix.de> |
| */ |
| |
| #ifndef _CAN_LENGTH_H |
| #define _CAN_LENGTH_H |
| |
| /* |
| * Size of a Classical CAN Standard Frame |
| * |
| * Name of Field Bits |
| * --------------------------------------------------------- |
| * Start-of-frame 1 |
| * Identifier 11 |
| * Remote transmission request (RTR) 1 |
| * Identifier extension bit (IDE) 1 |
| * Reserved bit (r0) 1 |
| * Data length code (DLC) 4 |
| * Data field 0...64 |
| * CRC 15 |
| * CRC delimiter 1 |
| * ACK slot 1 |
| * ACK delimiter 1 |
| * End-of-frame (EOF) 7 |
| * Inter frame spacing 3 |
| * |
| * rounded up and ignoring bitstuffing |
| */ |
| #define CAN_FRAME_OVERHEAD_SFF DIV_ROUND_UP(47, 8) |
| |
| /* |
| * Size of a Classical CAN Extended Frame |
| * |
| * Name of Field Bits |
| * --------------------------------------------------------- |
| * Start-of-frame 1 |
| * Identifier A 11 |
| * Substitute remote request (SRR) 1 |
| * Identifier extension bit (IDE) 1 |
| * Identifier B 18 |
| * Remote transmission request (RTR) 1 |
| * Reserved bits (r1, r0) 2 |
| * Data length code (DLC) 4 |
| * Data field 0...64 |
| * CRC 15 |
| * CRC delimiter 1 |
| * ACK slot 1 |
| * ACK delimiter 1 |
| * End-of-frame (EOF) 7 |
| * Inter frame spacing 3 |
| * |
| * rounded up and ignoring bitstuffing |
| */ |
| #define CAN_FRAME_OVERHEAD_EFF DIV_ROUND_UP(67, 8) |
| |
| /* |
| * Size of a CAN-FD Standard Frame |
| * |
| * Name of Field Bits |
| * --------------------------------------------------------- |
| * Start-of-frame 1 |
| * Identifier 11 |
| * Reserved bit (r1) 1 |
| * Identifier extension bit (IDE) 1 |
| * Flexible data rate format (FDF) 1 |
| * Reserved bit (r0) 1 |
| * Bit Rate Switch (BRS) 1 |
| * Error Status Indicator (ESI) 1 |
| * Data length code (DLC) 4 |
| * Data field 0...512 |
| * Stuff Bit Count (SBC) 0...16: 4 20...64:5 |
| * CRC 0...16: 17 20...64:21 |
| * CRC delimiter (CD) 1 |
| * ACK slot (AS) 1 |
| * ACK delimiter (AD) 1 |
| * End-of-frame (EOF) 7 |
| * Inter frame spacing 3 |
| * |
| * assuming CRC21, rounded up and ignoring bitstuffing |
| */ |
| #define CANFD_FRAME_OVERHEAD_SFF DIV_ROUND_UP(61, 8) |
| |
| /* |
| * Size of a CAN-FD Extended Frame |
| * |
| * Name of Field Bits |
| * --------------------------------------------------------- |
| * Start-of-frame 1 |
| * Identifier A 11 |
| * Substitute remote request (SRR) 1 |
| * Identifier extension bit (IDE) 1 |
| * Identifier B 18 |
| * Reserved bit (r1) 1 |
| * Flexible data rate format (FDF) 1 |
| * Reserved bit (r0) 1 |
| * Bit Rate Switch (BRS) 1 |
| * Error Status Indicator (ESI) 1 |
| * Data length code (DLC) 4 |
| * Data field 0...512 |
| * Stuff Bit Count (SBC) 0...16: 4 20...64:5 |
| * CRC 0...16: 17 20...64:21 |
| * CRC delimiter (CD) 1 |
| * ACK slot (AS) 1 |
| * ACK delimiter (AD) 1 |
| * End-of-frame (EOF) 7 |
| * Inter frame spacing 3 |
| * |
| * assuming CRC21, rounded up and ignoring bitstuffing |
| */ |
| #define CANFD_FRAME_OVERHEAD_EFF DIV_ROUND_UP(80, 8) |
| |
| /* |
| * Maximum size of a Classical CAN frame |
| * (rounded up and ignoring bitstuffing) |
| */ |
| #define CAN_FRAME_LEN_MAX (CAN_FRAME_OVERHEAD_EFF + CAN_MAX_DLEN) |
| |
| /* |
| * Maximum size of a CAN-FD frame |
| * (rounded up and ignoring bitstuffing) |
| */ |
| #define CANFD_FRAME_LEN_MAX (CANFD_FRAME_OVERHEAD_EFF + CANFD_MAX_DLEN) |
| |
| /* |
| * can_cc_dlc2len(value) - convert a given data length code (dlc) of a |
| * Classical CAN frame into a valid data length of max. 8 bytes. |
| * |
| * To be used in the CAN netdriver receive path to ensure conformance with |
| * ISO 11898-1 Chapter 8.4.2.3 (DLC field) |
| */ |
| #define can_cc_dlc2len(dlc) (min_t(u8, (dlc), CAN_MAX_DLEN)) |
| |
| /* helper to get the data length code (DLC) for Classical CAN raw DLC access */ |
| static inline u8 can_get_cc_dlc(const struct can_frame *cf, const u32 ctrlmode) |
| { |
| /* return len8_dlc as dlc value only if all conditions apply */ |
| if ((ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC) && |
| (cf->len == CAN_MAX_DLEN) && |
| (cf->len8_dlc > CAN_MAX_DLEN && cf->len8_dlc <= CAN_MAX_RAW_DLC)) |
| return cf->len8_dlc; |
| |
| /* return the payload length as dlc value */ |
| return cf->len; |
| } |
| |
| /* helper to set len and len8_dlc value for Classical CAN raw DLC access */ |
| static inline void can_frame_set_cc_len(struct can_frame *cf, const u8 dlc, |
| const u32 ctrlmode) |
| { |
| /* the caller already ensured that dlc is a value from 0 .. 15 */ |
| if (ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC && dlc > CAN_MAX_DLEN) |
| cf->len8_dlc = dlc; |
| |
| /* limit the payload length 'len' to CAN_MAX_DLEN */ |
| cf->len = can_cc_dlc2len(dlc); |
| } |
| |
| /* get data length from raw data length code (DLC) */ |
| u8 can_fd_dlc2len(u8 dlc); |
| |
| /* map the sanitized data length to an appropriate data length code */ |
| u8 can_fd_len2dlc(u8 len); |
| |
| /* calculate the CAN Frame length in bytes of a given skb */ |
| unsigned int can_skb_get_frame_len(const struct sk_buff *skb); |
| |
| /* map the data length to an appropriate data link layer length */ |
| static inline u8 canfd_sanitize_len(u8 len) |
| { |
| return can_fd_dlc2len(can_fd_len2dlc(len)); |
| } |
| |
| #endif /* !_CAN_LENGTH_H */ |
