include/linux/can/dev.h

/*
 * linux/can/dev.h
 *
 * Definitions for the CAN network device driver interface
 *
 * Copyright (C) 2006 Andrey Volkov <avolkov@varma-el.com>
 *               Varma Electronics Oy
 *
 * Copyright (C) 2008 Wolfgang Grandegger <wg@grandegger.com>
 *
 */

#ifndef CAN_DEV_H
#define CAN_DEV_H

#include <linux/can.h>
#include <linux/can/netlink.h>
#include <linux/can/error.h>

/*
 * CAN mode
 */
enum can_mode {
	CAN_MODE_STOP = 0,
	CAN_MODE_START,
	CAN_MODE_SLEEP
};

/*
 * CAN common private data
 */
struct can_priv {
	struct can_device_stats can_stats;

	struct can_bittiming bittiming;
	const struct can_bittiming_const *bittiming_const;
	struct can_clock clock;

	enum can_state state;
	u32 ctrlmode;
	u32 ctrlmode_supported;

	int restart_ms;
	struct timer_list restart_timer;

	int (*do_set_bittiming)(struct net_device *dev);
	int (*do_set_mode)(struct net_device *dev, enum can_mode mode);
	int (*do_get_state)(const struct net_device *dev,
			    enum can_state *state);
	int (*do_get_berr_counter)(const struct net_device *dev,
				   struct can_berr_counter *bec);

	unsigned int echo_skb_max;
	struct sk_buff **echo_skb;
};

/*
 * get_can_dlc(value) - helper macro to cast a given data length code (dlc)
 * to __u8 and ensure the dlc value to be max. 8 bytes.
 *
 * To be used in the CAN netdriver receive path to ensure conformance with
 * ISO 11898-1 Chapter 8.4.2.3 (DLC field)
 */
#define get_can_dlc(i)		(min_t(__u8, (i), CAN_MAX_DLC))
#define get_canfd_dlc(i)	(min_t(__u8, (i), CANFD_MAX_DLC))

/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
static inline int can_dropped_invalid_skb(struct net_device *dev,
					  struct sk_buff *skb)
{
	const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;

	if (skb->protocol == htons(ETH_P_CAN)) {
		if (unlikely(skb->len != CAN_MTU ||
			     cfd->len > CAN_MAX_DLEN))
			goto inval_skb;
	} else if (skb->protocol == htons(ETH_P_CANFD)) {
		if (unlikely(skb->len != CANFD_MTU ||
			     cfd->len > CANFD_MAX_DLEN))
			goto inval_skb;
	} else
		goto inval_skb;

	return 0;

inval_skb:
	kfree_skb(skb);
	dev->stats.tx_dropped++;
	return 1;
}

/* get data length from can_dlc with sanitized can_dlc */
u8 can_dlc2len(u8 can_dlc);

/* map the sanitized data length to an appropriate data length code */
u8 can_len2dlc(u8 len);

struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
void free_candev(struct net_device *dev);

int open_candev(struct net_device *dev);
void close_candev(struct net_device *dev);

int register_candev(struct net_device *dev);
void unregister_candev(struct net_device *dev);

int can_restart_now(struct net_device *dev);
void can_bus_off(struct net_device *dev);

void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
		      unsigned int idx);
unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx);
void can_free_echo_skb(struct net_device *dev, unsigned int idx);

struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);
struct sk_buff *alloc_can_err_skb(struct net_device *dev,
				  struct can_frame **cf);

#endif /* CAN_DEV_H */