From bdd2e413192dd5f2153d166cd907b048cce872e8 Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Mon, 11 Jan 2021 15:19:19 +0100 Subject: can: dev: move length related code into seperate file This patch moves all CAN frame length related code of the CAN device infrastructure into a separate file. Reviewed-by: Vincent Mailhol Link: https://lore.kernel.org/r/20210111141930.693847-5-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde --- include/linux/can/length.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 include/linux/can/length.h (limited to 'include/linux/can/length.h') diff --git a/include/linux/can/length.h b/include/linux/can/length.h new file mode 100644 index 000000000000..156b9d17969a --- /dev/null +++ b/include/linux/can/length.h @@ -0,0 +1,48 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2020 Oliver Hartkopp + */ + +#ifndef _CAN_LENGTH_H +#define _CAN_LENGTH_H + +/* + * 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); + +#endif /* !_CAN_LENGTH_H */ -- cgit v1.2.3