// SPDX-License-Identifier: GPL-2.0-only/* Copyright (C) 2012, 2020 Oliver Hartkopp <socketcan@hartkopp.net> */ #include <linux/can/dev.h> /* CAN DLC to real data length conversion helpers */ static const u8 dlc2len[] = {	0, 1, 2, 3, 4, 5, 6, 7,	8, 12, 16, 20, 24, 32, 48, 64}; /* get data length from raw data length code (DLC) */u8 can_fd_dlc2len(u8 dlc){	return dlc2len[dlc & 0x0F];}EXPORT_SYMBOL_GPL(can_fd_dlc2len); static const u8 len2dlc[] = {	0, 1, 2, 3, 4, 5, 6, 7, 8,	/* 0 - 8 */	9, 9, 9, 9,			/* 9 - 12 */	10, 10, 10, 10,			/* 13 - 16 */	11, 11, 11, 11,			/* 17 - 20 */	12, 12, 12, 12,			/* 21 - 24 */	13, 13, 13, 13, 13, 13, 13, 13,	/* 25 - 32 */	14, 14, 14, 14, 14, 14, 14, 14,	/* 33 - 40 */	14, 14, 14, 14, 14, 14, 14, 14,	/* 41 - 48 */	15, 15, 15, 15, 15, 15, 15, 15,	/* 49 - 56 */	15, 15, 15, 15, 15, 15, 15, 15	/* 57 - 64 */}; /* map the sanitized data length to an appropriate data length code */u8 can_fd_len2dlc(u8 len){	/* check for length mapping table size at build time */	BUILD_BUG_ON(ARRAY_SIZE(len2dlc) != CANFD_MAX_DLEN + 1); 	if (unlikely(len > CANFD_MAX_DLEN))		return CANFD_MAX_DLC; 	return len2dlc[len];}EXPORT_SYMBOL_GPL(can_fd_len2dlc); /** * can_skb_get_frame_len() - Calculate the CAN Frame length in bytes * 	of a given skb. * @skb: socket buffer of a CAN message. * * Do a rough calculation: bit stuffing is ignored and length in bits * is rounded up to a length in bytes. * * Rationale: this function is to be used for the BQL functions * (netdev_sent_queue() and netdev_completed_queue()) which expect a * value in bytes. Just using skb->len is insufficient because it will * return the constant value of CAN(FD)_MTU. Doing the bit stuffing * calculation would be too expensive in term of computing resources * for no noticeable gain. * * Remarks: The payload of CAN FD frames with BRS flag are sent at a * different bitrate. Currently, the can-utils canbusload tool does * not support CAN-FD yet and so we could not run any benchmark to * measure the impact. There might be possible improvement here. * * Return: length in bytes. */unsigned int can_skb_get_frame_len(const struct sk_buff *skb){	const struct canfd_frame *cf = (const struct canfd_frame *)skb->data;	u8 len; 	if (can_is_canfd_skb(skb))		len = canfd_sanitize_len(cf->len);	else if (cf->can_id & CAN_RTR_FLAG)		len = 0;	else		len = cf->len; 	return can_frame_bytes(can_is_canfd_skb(skb), cf->can_id & CAN_EFF_FLAG,			       false, len);}EXPORT_SYMBOL_GPL(can_skb_get_frame_len);