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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485// 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);