include/linux/can/dev.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * linux/can/dev.h
   4  *
   5  * Definitions for the CAN network device driver interface
   6  *
   7  * Copyright (C) 2006 Andrey Volkov <avolkov@varma-el.com>
   8  *               Varma Electronics Oy
   9  *
  10  * Copyright (C) 2008 Wolfgang Grandegger <wg@grandegger.com>
  11  *
  12  */
  13
  14 #ifndef _CAN_DEV_H
  15 #define _CAN_DEV_H
  16
  17 #include <linux/can.h>
  18 #include <linux/can/error.h>
  19 #include <linux/can/led.h>
  20 #include <linux/can/netlink.h>
  21 #include <linux/can/skb.h>
  22 #include <linux/netdevice.h>
  23
  24 /*
  25  * CAN mode
  26  */
  27 enum can_mode {
  28         CAN_MODE_STOP = 0,
  29         CAN_MODE_START,
  30         CAN_MODE_SLEEP
  31 };
  32
  33 /*
  34  * CAN common private data
  35  */
  36 struct can_priv {
  37         struct net_device *dev;
  38         struct can_device_stats can_stats;
  39
  40         struct can_bittiming bittiming, data_bittiming;
  41         const struct can_bittiming_const *bittiming_const,
  42                 *data_bittiming_const;
  43         const u16 *termination_const;
  44         unsigned int termination_const_cnt;
  45         u16 termination;
  46         const u32 *bitrate_const;
  47         unsigned int bitrate_const_cnt;
  48         const u32 *data_bitrate_const;
  49         unsigned int data_bitrate_const_cnt;
  50         struct can_clock clock;
  51
  52         enum can_state state;
  53
  54         /* CAN controller features - see include/uapi/linux/can/netlink.h */
  55         u32 ctrlmode;           /* current options setting */
  56         u32 ctrlmode_supported; /* options that can be modified by netlink */
  57         u32 ctrlmode_static;    /* static enabled options for driver/hardware */
  58
  59         int restart_ms;
  60         struct delayed_work restart_work;
  61
  62         int (*do_set_bittiming)(struct net_device *dev);
  63         int (*do_set_data_bittiming)(struct net_device *dev);
  64         int (*do_set_mode)(struct net_device *dev, enum can_mode mode);
  65         int (*do_set_termination)(struct net_device *dev, u16 term);
  66         int (*do_get_state)(const struct net_device *dev,
  67                             enum can_state *state);
  68         int (*do_get_berr_counter)(const struct net_device *dev,
  69                                    struct can_berr_counter *bec);
  70
  71         unsigned int echo_skb_max;
  72         struct sk_buff **echo_skb;
  73
  74 #ifdef CONFIG_CAN_LEDS
  75         struct led_trigger *tx_led_trig;
  76         char tx_led_trig_name[CAN_LED_NAME_SZ];
  77         struct led_trigger *rx_led_trig;
  78         char rx_led_trig_name[CAN_LED_NAME_SZ];
  79         struct led_trigger *rxtx_led_trig;
  80         char rxtx_led_trig_name[CAN_LED_NAME_SZ];
  81 #endif
  82 };
  83
  84 /*
  85  * get_can_dlc(value) - helper macro to cast a given data length code (dlc)
  86  * to __u8 and ensure the dlc value to be max. 8 bytes.
  87  *
  88  * To be used in the CAN netdriver receive path to ensure conformance with
  89  * ISO 11898-1 Chapter 8.4.2.3 (DLC field)
  90  */
  91 #define get_can_dlc(i)          (min_t(__u8, (i), CAN_MAX_DLC))
  92 #define get_canfd_dlc(i)        (min_t(__u8, (i), CANFD_MAX_DLC))
  93
  94 /* Check for outgoing skbs that have not been created by the CAN subsystem */
  95 static inline bool can_skb_headroom_valid(struct net_device *dev,
  96                                           struct sk_buff *skb)
  97 {
  98         /* af_packet creates a headroom of HH_DATA_MOD bytes which is fine */
  99         if (WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct can_skb_priv)))
 100                 return false;
 101
 102         /* af_packet does not apply CAN skb specific settings */
 103         if (skb->ip_summed == CHECKSUM_NONE) {
 104                 /* init headroom */
 105                 can_skb_prv(skb)->ifindex = dev->ifindex;
 106                 can_skb_prv(skb)->skbcnt = 0;
 107
 108                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 109
 110                 /* preform proper loopback on capable devices */
 111                 if (dev->flags & IFF_ECHO)
 112                         skb->pkt_type = PACKET_LOOPBACK;
 113                 else
 114                         skb->pkt_type = PACKET_HOST;
 115
 116                 skb_reset_mac_header(skb);
 117                 skb_reset_network_header(skb);
 118                 skb_reset_transport_header(skb);
 119         }
 120
 121         return true;
 122 }
 123
 124 /* Drop a given socketbuffer if it does not contain a valid CAN frame. */
 125 static inline bool can_dropped_invalid_skb(struct net_device *dev,
 126                                           struct sk_buff *skb)
 127 {
 128         const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
 129
 130         if (skb->protocol == htons(ETH_P_CAN)) {
 131                 if (unlikely(skb->len != CAN_MTU ||
 132                              cfd->len > CAN_MAX_DLEN))
 133                         goto inval_skb;
 134         } else if (skb->protocol == htons(ETH_P_CANFD)) {
 135                 if (unlikely(skb->len != CANFD_MTU ||
 136                              cfd->len > CANFD_MAX_DLEN))
 137                         goto inval_skb;
 138         } else
 139                 goto inval_skb;
 140
 141         if (!can_skb_headroom_valid(dev, skb))
 142                 goto inval_skb;
 143
 144         return false;
 145
 146 inval_skb:
 147         kfree_skb(skb);
 148         dev->stats.tx_dropped++;
 149         return true;
 150 }
 151
 152 static inline bool can_is_canfd_skb(const struct sk_buff *skb)
 153 {
 154         /* the CAN specific type of skb is identified by its data length */
 155         return skb->len == CANFD_MTU;
 156 }
 157
 158 /* helper to define static CAN controller features at device creation time */
 159 static inline void can_set_static_ctrlmode(struct net_device *dev,
 160                                            u32 static_mode)
 161 {
 162         struct can_priv *priv = netdev_priv(dev);
 163
 164         /* alloc_candev() succeeded => netdev_priv() is valid at this point */
 165         priv->ctrlmode = static_mode;
 166         priv->ctrlmode_static = static_mode;
 167
 168         /* override MTU which was set by default in can_setup()? */
 169         if (static_mode & CAN_CTRLMODE_FD)
 170                 dev->mtu = CANFD_MTU;
 171 }
 172
 173 /* get data length from can_dlc with sanitized can_dlc */
 174 u8 can_dlc2len(u8 can_dlc);
 175
 176 /* map the sanitized data length to an appropriate data length code */
 177 u8 can_len2dlc(u8 len);
 178
 179 struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
 180 void free_candev(struct net_device *dev);
 181
 182 /* a candev safe wrapper around netdev_priv */
 183 struct can_priv *safe_candev_priv(struct net_device *dev);
 184
 185 int open_candev(struct net_device *dev);
 186 void close_candev(struct net_device *dev);
 187 int can_change_mtu(struct net_device *dev, int new_mtu);
 188
 189 int register_candev(struct net_device *dev);
 190 void unregister_candev(struct net_device *dev);
 191
 192 int can_restart_now(struct net_device *dev);
 193 void can_bus_off(struct net_device *dev);
 194
 195 void can_change_state(struct net_device *dev, struct can_frame *cf,
 196                       enum can_state tx_state, enum can_state rx_state);
 197
 198 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 199                       unsigned int idx);
 200 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr);
 201 unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx);
 202 void can_free_echo_skb(struct net_device *dev, unsigned int idx);
 203
 204 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);
 205 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 206                                 struct canfd_frame **cfd);
 207 struct sk_buff *alloc_can_err_skb(struct net_device *dev,
 208                                   struct can_frame **cf);
 209
 210 #endif /* !_CAN_DEV_H */