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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 <mailhol.vincent@wanadoo.fr> Link: https://lore.kernel.org/r/20210111141930.693847-5-mkl@pengutronix.de Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,38 @@ | ||
| // SPDX-License-Identifier: GPL-2.0-only | ||
| /* Copyright (C) 2012, 2020 Oliver Hartkopp <socketcan@hartkopp.net> | ||
| */ | ||
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| #include <linux/can/dev.h> | ||
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| /* CAN DLC to real data length conversion helpers */ | ||
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| static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7, | ||
| 8, 12, 16, 20, 24, 32, 48, 64}; | ||
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| /* 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); | ||
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| 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 */ | ||
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| /* map the sanitized data length to an appropriate data length code */ | ||
| u8 can_fd_len2dlc(u8 len) | ||
| { | ||
| if (unlikely(len > 64)) | ||
| return 0xF; | ||
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| return len2dlc[len]; | ||
| } | ||
| EXPORT_SYMBOL_GPL(can_fd_len2dlc); |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,48 @@ | ||
| /* SPDX-License-Identifier: GPL-2.0 */ | ||
| /* Copyright (C) 2020 Oliver Hartkopp <socketcan@hartkopp.net> | ||
| */ | ||
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| #ifndef _CAN_LENGTH_H | ||
| #define _CAN_LENGTH_H | ||
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| /* | ||
| * 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)) | ||
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| /* 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; | ||
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| /* return the payload length as dlc value */ | ||
| return cf->len; | ||
| } | ||
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| /* 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; | ||
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| /* limit the payload length 'len' to CAN_MAX_DLEN */ | ||
| cf->len = can_cc_dlc2len(dlc); | ||
| } | ||
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| /* get data length from raw data length code (DLC) */ | ||
| u8 can_fd_dlc2len(u8 dlc); | ||
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| /* map the sanitized data length to an appropriate data length code */ | ||
| u8 can_fd_len2dlc(u8 len); | ||
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| #endif /* !_CAN_LENGTH_H */ |