This patch adds defines for data structures and length information for
CAN XL (CAN with eXtended data Length) which can transfer up to 2048
byte insinde a single frame.
Notable changes from CAN FD:
- the 11 bit arbitration field is now named 'priority' instead of 'can_id'
(there are no 29 bit identifiers nor RTR frames anymore)
- the data length needs a uint16 value to cover up to 2048 byte
(the length element position is different to struct can[fd]_frame)
- new fields (SDT, AF) and a SEC bit have been introduced
- the virtual CAN interface identifier is not part if the CAN XL frame
struct as this VCID value is stored in struct skbuff (analog to vlan id)
Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
---
include/uapi/linux/can.h | 50 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 50 insertions(+)
diff --git a/include/uapi/linux/can.h b/include/uapi/linux/can.h
index 90801ada2bbe..d5c99ead8df0 100644
--- a/include/uapi/linux/can.h
+++ b/include/uapi/linux/can.h
@@ -46,10 +46,11 @@
#ifndef _UAPI_CAN_H
#define _UAPI_CAN_H
#include <linux/types.h>
#include <linux/socket.h>
+#include <linux/stddef.h> /* for offsetof */
/* controller area network (CAN) kernel definitions */
/* special address description flags for the CAN_ID */
#define CAN_EFF_FLAG 0x80000000U /* EFF/SFF is set in the MSB */
@@ -58,10 +59,11 @@
/* valid bits in CAN ID for frame formats */
#define CAN_SFF_MASK 0x000007FFU /* standard frame format (SFF) */
#define CAN_EFF_MASK 0x1FFFFFFFU /* extended frame format (EFF) */
#define CAN_ERR_MASK 0x1FFFFFFFU /* omit EFF, RTR, ERR flags */
+#define CANXL_PRIO_MASK CAN_SFF_MASK /* 11 bit priority mask */
/*
* Controller Area Network Identifier structure
*
* bit 0-28 : CAN identifier (11/29 bit)
@@ -71,10 +73,11 @@
*/
typedef __u32 canid_t;
#define CAN_SFF_ID_BITS 11
#define CAN_EFF_ID_BITS 29
+#define CANXL_PRIO_BITS CAN_SFF_ID_BITS
/*
* Controller Area Network Error Message Frame Mask structure
*
* bit 0-28 : error class mask (see include/uapi/linux/can/error.h)
@@ -89,10 +92,20 @@ typedef __u32 can_err_mask_t;
/* CAN FD payload length and DLC definitions according to ISO 11898-7 */
#define CANFD_MAX_DLC 15
#define CANFD_MAX_DLEN 64
+/*
+ * CAN XL payload length and DLC definitions according to ISO 11898-1
+ * CAN XL DLC ranges from 0 .. 2047 => data length from 1 .. 2048 byte
+ */
+#define CANXL_MIN_DLC 0
+#define CANXL_MAX_DLC 2047
+#define CANXL_MAX_DLC_MASK 0x07FF
+#define CANXL_MIN_DLEN 1
+#define CANXL_MAX_DLEN 2048
+
/**
* struct can_frame - Classical CAN frame structure (aka CAN 2.0B)
* @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)
@@ -164,12 +177,49 @@ struct canfd_frame {
__u8 __res0; /* reserved / padding */
__u8 __res1; /* reserved / padding */
__u8 data[CANFD_MAX_DLEN] __attribute__((aligned(8)));
};
+/*
+ * defined bits for canxl_frame.flags
+ *
+ * The canxl_frame.flags element contains two bits CANXL_XLF and CANXL_SEC
+ * and shares the relative position of the struct can[fd]_frame.len element.
+ * The CANXL_XLF bit ALWAYS needs to be set to indicate a valid CAN XL frame.
+ * As a side effect setting this bit intentionally breaks the length checks
+ * for Classical CAN and CAN FD frames.
+ *
+ * Undefined bits in canxl_frame.flags are reserved and shall be set to zero.
+ */
+#define CANXL_XLF 0x80 /* mandatory CAN XL frame flag (must always be set!) */
+#define CANXL_SEC 0x01 /* Simple Extended Content (security/segmentation) */
+
+/**
+ * struct canxl_frame - CAN with e'X'tended frame 'L'ength frame structure
+ * @prio: 11 bit arbitration priority with zero'ed CAN_*_FLAG flags
+ * @flags: additional flags for CAN XL
+ * @sdt: SDU (service data unit) type
+ * @len: frame payload length in byte (1 .. CANXL_MAX_DLEN)
+ * @af: acceptance field
+ * @data: CAN XL frame payload (up to CANXL_MAX_DLEN byte)
+ *
+ * @prio shares the same position as @can_id from struct can[fd]_frame.
+ */
+struct canxl_frame {
+ canid_t prio; /* 11 bit priority for arbitration (canid_t) */
+ __u8 flags; /* additional flags for CAN XL */
+ __u8 sdt; /* SDU (service data unit) type */
+ __u16 len; /* frame payload length in byte */
+ __u32 af; /* acceptance field */
+ __u8 data[CANXL_MAX_DLEN];
+};
+
#define CAN_MTU (sizeof(struct can_frame))
#define CANFD_MTU (sizeof(struct canfd_frame))
+#define CANXL_MTU (sizeof(struct canxl_frame))
+#define CANXL_HEAD_SZ (offsetof(struct canxl_frame, data))
+#define CANXL_MINTU (CANXL_HEAD_SZ + CANXL_MIN_DLEN)
/* particular protocols of the protocol family PF_CAN */
#define CAN_RAW 1 /* RAW sockets */
#define CAN_BCM 2 /* Broadcast Manager */
#define CAN_TP16 3 /* VAG Transport Protocol v1.6 */
--
2.30.2
