Merge patch series "can: support CAN XL"

Oliver Hartkopp <socketcan@hartkopp.net> says:

The CAN with eXtended data Length (CAN XL) is a new CAN protocol with
a 10Mbit/s data transfer with a new physical layer transceiver (for
this data section). CAN XL allows up to 2048 byte of payload and
shares the arbitration principle (11 bit priority) known from
Classical CAN and CAN FD. RTR and 29 bit identifiers are not
implemented in CAN XL.

A short introduction to CAN XL can be found here:
https://www.can-cia.org/can-knowledge/can/can-xl/
https://github.com/linux-can/can-doc/blob/master/presentations/CAN-XL-Intro.pdf

V1: https://lore.kernel.org/all/20220711183426.96446-1-socketcan@hartkopp.net

V2: Major rework after discussion and feedback on Linux-CAN ML
    https://lore.kernel.org/all/20220714160541.2071-1-socketcan@hartkopp.net

- rework of struct canxl_frame
- CANXL_XLF flag is now the switch between CAN XL and CAN/CANFD
- variable length in r/w operations for CAN XL frames
- write CAN XL frame to raw socket enforces size <-> canxl_frame.len sync

V3: Fix length for CAN XL frames inside the sk_buff
    https://lore.kernel.org/all/20220717132730.30295-1-socketcan@hartkopp.net

- extend the CAN_RAW sockopt to handle fixed/truncated read/write operations

V4: Fix patch 5 (can: raw: add CAN XL support)
    https://lore.kernel.org/all/20220719054204.29061-1-socketcan@hartkopp.net

- fix return value (move 'err = -EINVAL' in raw_sendmsg())
- add CAN XL frame handling in can_rcv()
- change comment for CAN_RAW_XL_[RT]X_DYN definition (allow -> enable)

V5: Remove CAN_RAW_XL_[RT]X_DYN definition again
    https://lore.kernel.org/all/20220719112748.3281-1-socketcan@hartkopp.net

- CAN_RAW_XL_[RT]X_DYN (truncated data) feature is now enabled by default
- use CANXL_MIN_DLEN instead of '1' in canxl_frame definition
- add missing 'err = -EINVAL' initialization in raw_sendmsg())

V6: https://lore.kernel.org/all/20220724074402.117394-1-socketcan@hartkopp.net

- rework an separate skb identification and length helpers
- add CANFD_FDF flag in all CAN FD frame structures
- simplify patches for infrastructure and raw sockets
- add vxcan support in virtual CAN interface patch

V7: https://lore.kernel.org/all/20220729154107.1875-1-socketcan@hartkopp.net

- fixed indention as remarked by Marc
- set CANFD_FDF flag when detecting CAN FD frames generated by PF_PACKET
- Allow to use variable CAN XL MTU sizes to enforce real time requirements
  on CAN XL segments (e.g. to support of CAN CiA segmentation concept)

V8: https://lore.kernel.org/all/20220801190010.3344-1-socketcan@hartkopp.net

- fixed typo as remarked by Vincent
- rebased to latest can-next/net-next tree

V9: https://lore.kernel.org/all/20220912170725.120748-1-socketcan@hartkopp.net

- rebased to latest can-next/net-next tree
- updated and extended public available CAN XL documenatation in cover letter
- renamed struct canxl_frame variable cfx to cxl as suggested by Vincent
- Added Acked-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> tag

Link: https://lore.kernel.org/all/20220912170725.120748-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

3 files changed, 55 insertions, 2 deletions

diff --git a/include/uapi/linux/can.h b/include/uapi/linux/can.h
index 90801ada2bbe..dd645ea72306 100644
--- a/include/uapi/linux/can.h
+++ b/include/uapi/linux/can.h
@@ -48,6 +48,7 @@
 
 #include <linux/types.h>
 #include <linux/socket.h>
+#include <linux/stddef.h> /* for offsetof */
 
 /* controller area network (CAN) kernel definitions */
 
@@ -60,6 +61,7 @@
 #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
@@ -73,6 +75,7 @@ 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
@@ -91,6 +94,16 @@ typedef __u32 can_err_mask_t;
 #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
@@ -141,8 +154,8 @@ struct can_frame {
  * When this is done the former differentiation via CAN_MTU / CANFD_MTU gets
  * lost. CANFD_FDF allows programmers to mark CAN FD frames in the case of
  * using struct canfd_frame for mixed CAN / CAN FD content (dual use).
- * N.B. the Kernel APIs do NOT provide mixed CAN / CAN FD content inside of
- * struct canfd_frame therefore the CANFD_FDF flag is disregarded by Linux.
+ * Since the introduction of CAN XL the CANFD_FDF flag is set in all CAN FD
+ * frame structures provided by the CAN subsystem of the Linux kernel.
  */
 #define CANFD_BRS 0x01 /* bit rate switch (second bitrate for payload data) */
 #define CANFD_ESI 0x02 /* error state indicator of the transmitting node */
@@ -166,8 +179,46 @@ struct canfd_frame {
 	__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 (CANXL_MIN_DLEN .. CANXL_MAX_DLEN)
+ * @af:    acceptance field
+ * @data:  CAN XL frame payload (CANXL_MIN_DLEN .. 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_HDR_SIZE	(offsetof(struct canxl_frame, data))
+#define CANXL_MIN_MTU	(CANXL_HDR_SIZE + 64)
+#define CANXL_MAX_MTU	CANXL_MTU
 
 /* particular protocols of the protocol family PF_CAN */
 #define CAN_RAW		1 /* RAW sockets */
diff --git a/include/uapi/linux/can/raw.h b/include/uapi/linux/can/raw.h
index 3386aa81fdf2..ff12f525c37c 100644
--- a/include/uapi/linux/can/raw.h
+++ b/include/uapi/linux/can/raw.h
@@ -62,6 +62,7 @@ enum {
 	CAN_RAW_RECV_OWN_MSGS,	/* receive my own msgs (default:off) */
 	CAN_RAW_FD_FRAMES,	/* allow CAN FD frames (default:off) */
 	CAN_RAW_JOIN_FILTERS,	/* all filters must match to trigger */
+	CAN_RAW_XL_FRAMES,	/* allow CAN XL frames (default:off) */
 };
 
 #endif /* !_UAPI_CAN_RAW_H */
diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index d370165bc621..69e0457eb200 100644
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -138,6 +138,7 @@
 #define ETH_P_LOCALTALK 0x0009		/* Localtalk pseudo type 	*/
 #define ETH_P_CAN	0x000C		/* CAN: Controller Area Network */
 #define ETH_P_CANFD	0x000D		/* CANFD: CAN flexible data rate*/
+#define ETH_P_CANXL	0x000E		/* CANXL: eXtended frame Length */
 #define ETH_P_PPPTALK	0x0010		/* Dummy type for Atalk over PPP*/
 #define ETH_P_TR_802_2	0x0011		/* 802.2 frames 		*/
 #define ETH_P_MOBITEX	0x0015		/* Mobitex (kaz@cafe.net)	*/