Whole CAN code in RIOT is using 'struct can_frame' to represent a CAN
frame.
However incoming CAN FD support will bring 'struct canfd_frame' to
represent CAN FD frames.
Even if the 'struct canfd_frame' has additional flags and a bigger
payload, it is aligned on 'struct can_frame' and thus they can be
referenced by the same pointers in the code.
As it is impossible to predict which one will be used in RIOT, just
define a new type 'can_frame_t' which will map to the right struct
according to the MCU CAN supported format.
Signed-off-by: Gilles DOFFE <gilles.doffe@rtone.fr>
RIOT implementation of CAN bus relies on SocketCAN model.
Since commit c398e56 (can: add optional DLC element to Classical CAN
frame structure), '__u8 can_dlc' attribute of struct can_frame is
considered as deprecated in SocketCAN and kept for legacy support.
Attribute '__u8 len' should be used instead.
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 */
};
Moreover, CAN FD frame structure does not support legacy attribute
'can_dlc', making 'len' mandatory for incoming CAN FD support in RIOT.
struct canfd_frame {
canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */
__u8 len; /* frame payload length in byte */
__u8 flags; /* additional flags for CAN FD */
__u8 __res0; /* reserved / padding */
__u8 __res1; /* reserved / padding */
__u8 data[CANFD_MAX_DLEN]
__attribute__((aligned(8)));
};
Signed-off-by: Gilles DOFFE <gilles.doffe@rtone.fr>
We do not need to add an array of pointers to the shell commands, just
an array of shell commands is sufficient. This reduced the overhead of
XFA by `sizeof(void *)` per command.
This command does the same as `help`, but provides a machine readable
JSON rather than a human readable table. It is only provided when the
(pseudo-)module `shell_builtin_cmd_help_json` is used.
It would seem that either we need to require the periph_pm module in shell
or make it optional... since we have many other optional modules here
and we still may want the RIOT_VERSION command, lets make it optional for now.
