On 29.10.20 17:32, Oliver Hartkopp wrote:
> /* CAN FD payload length and DLC definitions according to ISO 11898-7 */
> #define CANFD_MAX_DLC 15
> #define CANFD_MAX_DLEN 64
>
> /**
> * struct can_frame - basic CAN frame structure
struct can_frame - Classical CAN frame structure.
This is just a nitpick but I was reading again the past email
exchanges and using "Classical CAN" instead of "basic CAN" here would
be more consistent and help people to better understand the CC
acronym.
> - * @can_id: CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition
> - * @can_dlc: frame payload length in byte (0 .. 8) aka data length code
> - * N.B. the DLC field from ISO 11898-1 Chapter 8.4.2.3 has a 1:1
> - * mapping of the 'data length code' to the real payload length
> - * @__pad: padding
> - * @__res0: reserved / padding
> - * @__res1: reserved / padding
> - * @data: CAN frame payload (up to 8 byte)
> + * @can_id: CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition
> + * @len: CAN frame payload length in byte (0 .. 8)
> + * @can_dlc: deprecated name for CAN frame payload length in byte (0 .. 8)
> + * @__pad: padding
> + * @__res0: reserved / padding
> + * @len8_dlc: optional DLC value (9 .. 15) at 8 byte payload length
> + * len8_dlc contains values from 9 .. 15 when the payload length is
> + * 8 bytes but the DLC value (see ISO 11898-1) is greater then 8.
> + * CAN_CTRLMODE_CC_LEN8_DLC flag has to be enabled in CAN driver.
> + * @data: CAN frame payload (up to 8 byte)
> */
> struct can_frame {
> canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */
> - __u8 can_dlc; /* frame payload length in byte (0 .. CAN_MAX_DLEN) */
> - __u8 __pad; /* padding */
> - __u8 __res0; /* reserved / padding */
> - __u8 __res1; /* reserved / padding */
> - __u8 data[CAN_MAX_DLEN] __attribute__((aligned(8)));
> + union {
> + /* CAN frame payload length in byte (0 .. CAN_MAX_DLEN)
> + * was previously named can_dlc so we need to carry that
> + * name for legacy support
> + */
> + __u8 len;
> + __u8 can_dlc; /* deprecated */
> + };
> + __u8 __pad; /* padding */
> + __u8 __res0; /* reserved / padding */
> + __u8 len8_dlc; /* optional DLC for 8 byte payload length (9 .. 15) */
> + __u8 data[CAN_MAX_DLEN] __attribute__((aligned(8)));
> };
Yours sincerely,
Vincent Mailhol
