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author | Vincent Mailhol <mailhol.vincent@wanadoo.fr> | 2023-06-11 11:57:28 +0900 |
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committer | Marc Kleine-Budde <mkl@pengutronix.de> | 2023-06-22 09:43:40 +0200 |
commit | 80a2fbce456e3f73b4f49ce12fefa3215a3d0773 (patch) | |
tree | ee861aa89efdfc002417411264aa084e0ce0c014 /drivers/net/can/dev | |
parent | 10711b11102bfc351240982d46a51d4eecc28c10 (diff) | |
download | linux-80a2fbce456e3f73b4f49ce12fefa3215a3d0773.tar.gz linux-80a2fbce456e3f73b4f49ce12fefa3215a3d0773.tar.bz2 linux-80a2fbce456e3f73b4f49ce12fefa3215a3d0773.zip |
can: length: refactor frame lengths definition to add size in bits
Introduce a method to calculate the exact size in bits of a CAN(-FD)
frame with or without dynamic bitstuffing.
These are all the possible combinations taken into account:
- Classical CAN or CAN-FD
- Standard or Extended frame format
- CAN-FD CRC17 or CRC21
- Include or not intermission
Instead of doing several individual macro definitions, declare the
can_frame_bits() function-like macro. To this extent, do a full
refactoring of the length definitions.
In addition add the can_frame_bytes(). This function-like macro
replaces the existing macro:
- CAN_FRAME_OVERHEAD_SFF: can_frame_bytes(false, false, 0)
- CAN_FRAME_OVERHEAD_EFF: can_frame_bytes(false, true, 0)
- CANFD_FRAME_OVERHEAD_SFF: can_frame_bytes(true, false, 0)
- CANFD_FRAME_OVERHEAD_EFF: can_frame_bytes(true, true, 0)
Function-like macros were chosen over inline functions because they
can be used to initialize const struct fields.
The different maximum frame lengths (maximum data length, including
intermission) are as follow:
Frame type bits bytes
-------------------------------------------------------
Classic CAN SFF no bitstuffing 111 14
Classic CAN EFF no bitstuffing 131 17
Classic CAN SFF bitstuffing 135 17
Classic CAN EFF bitstuffing 160 20
CAN-FD SFF no bitstuffing 579 73
CAN-FD EFF no bitstuffing 598 75
CAN-FD SFF bitstuffing 712 89
CAN-FD EFF bitstuffing 736 92
The macro CAN_FRAME_LEN_MAX and CANFD_FRAME_LEN_MAX are kept as an
alias to, respectively, can_frame_bytes(false, true, CAN_MAX_DLEN) and
can_frame_bytes(true, true, CANFD_MAX_DLEN).
In addition to the above:
- Use ISO 11898-1:2015 definitions for the names of the CAN frame
fields.
- Include linux/bits.h for use of BITS_PER_BYTE.
- Include linux/math.h for use of mult_frac() and
DIV_ROUND_UP(). N.B: the use of DIV_ROUND_UP() is not new to this
patch, but the include was previously omitted.
- Add copyright 2023 for myself.
Suggested-by: Thomas Kopp <Thomas.Kopp@microchip.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Reviewed-by: Thomas Kopp <Thomas.Kopp@microchip.com>
Link: https://lore.kernel.org/all/20230611025728.450837-4-mailhol.vincent@wanadoo.fr
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Diffstat (limited to 'drivers/net/can/dev')
-rw-r--r-- | drivers/net/can/dev/length.c | 15 |
1 files changed, 2 insertions, 13 deletions
diff --git a/drivers/net/can/dev/length.c b/drivers/net/can/dev/length.c index b48140b1102e..b7f4d76dd444 100644 --- a/drivers/net/can/dev/length.c +++ b/drivers/net/can/dev/length.c @@ -78,18 +78,7 @@ unsigned int can_skb_get_frame_len(const struct sk_buff *skb) else len = cf->len; - if (can_is_canfd_skb(skb)) { - if (cf->can_id & CAN_EFF_FLAG) - len += CANFD_FRAME_OVERHEAD_EFF; - else - len += CANFD_FRAME_OVERHEAD_SFF; - } else { - if (cf->can_id & CAN_EFF_FLAG) - len += CAN_FRAME_OVERHEAD_EFF; - else - len += CAN_FRAME_OVERHEAD_SFF; - } - - return 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); |