49 lines
1.5 KiB
C
49 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* Copyright (C) 2020 Oliver Hartkopp <socketcan@hartkopp.net>
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*/
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#ifndef _CAN_LENGTH_H
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#define _CAN_LENGTH_H
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/*
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* can_cc_dlc2len(value) - convert a given data length code (dlc) of a
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* Classical CAN frame into a valid data length of max. 8 bytes.
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*
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* To be used in the CAN netdriver receive path to ensure conformance with
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* ISO 11898-1 Chapter 8.4.2.3 (DLC field)
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*/
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#define can_cc_dlc2len(dlc) (min_t(u8, (dlc), CAN_MAX_DLEN))
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/* helper to get the data length code (DLC) for Classical CAN raw DLC access */
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static inline u8 can_get_cc_dlc(const struct can_frame *cf, const u32 ctrlmode)
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{
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/* return len8_dlc as dlc value only if all conditions apply */
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if ((ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC) &&
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(cf->len == CAN_MAX_DLEN) &&
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(cf->len8_dlc > CAN_MAX_DLEN && cf->len8_dlc <= CAN_MAX_RAW_DLC))
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return cf->len8_dlc;
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/* return the payload length as dlc value */
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return cf->len;
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}
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/* helper to set len and len8_dlc value for Classical CAN raw DLC access */
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static inline void can_frame_set_cc_len(struct can_frame *cf, const u8 dlc,
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const u32 ctrlmode)
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{
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/* the caller already ensured that dlc is a value from 0 .. 15 */
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if (ctrlmode & CAN_CTRLMODE_CC_LEN8_DLC && dlc > CAN_MAX_DLEN)
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cf->len8_dlc = dlc;
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/* limit the payload length 'len' to CAN_MAX_DLEN */
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cf->len = can_cc_dlc2len(dlc);
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}
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/* get data length from raw data length code (DLC) */
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u8 can_fd_dlc2len(u8 dlc);
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/* map the sanitized data length to an appropriate data length code */
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u8 can_fd_len2dlc(u8 len);
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#endif /* !_CAN_LENGTH_H */
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