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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 */
27enum can_mode {
28 CAN_MODE_STOP = 0,
29 CAN_MODE_START,
30 CAN_MODE_SLEEP
31};
32
33/*
34 * CAN common private data
35 */
36struct 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 u32 bitrate_max;
51 struct can_clock clock;
52
53 enum can_state state;
54
55 /* CAN controller features - see include/uapi/linux/can/netlink.h */
56 u32 ctrlmode; /* current options setting */
57 u32 ctrlmode_supported; /* options that can be modified by netlink */
58 u32 ctrlmode_static; /* static enabled options for driver/hardware */
59
60 int restart_ms;
61 struct delayed_work restart_work;
62
63 int (*do_set_bittiming)(struct net_device *dev);
64 int (*do_set_data_bittiming)(struct net_device *dev);
65 int (*do_set_mode)(struct net_device *dev, enum can_mode mode);
66 int (*do_set_termination)(struct net_device *dev, u16 term);
67 int (*do_get_state)(const struct net_device *dev,
68 enum can_state *state);
69 int (*do_get_berr_counter)(const struct net_device *dev,
70 struct can_berr_counter *bec);
71
72 unsigned int echo_skb_max;
73 struct sk_buff **echo_skb;
74
75#ifdef CONFIG_CAN_LEDS
76 struct led_trigger *tx_led_trig;
77 char tx_led_trig_name[CAN_LED_NAME_SZ];
78 struct led_trigger *rx_led_trig;
79 char rx_led_trig_name[CAN_LED_NAME_SZ];
80 struct led_trigger *rxtx_led_trig;
81 char rxtx_led_trig_name[CAN_LED_NAME_SZ];
82#endif
83};
84
85#define CAN_SYNC_SEG 1
86
87/*
88 * can_bit_time() - Duration of one bit
89 *
90 * Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for
91 * additional information.
92 *
93 * Return: the number of time quanta in one bit.
94 */
95static inline unsigned int can_bit_time(const struct can_bittiming *bt)
96{
97 return CAN_SYNC_SEG + bt->prop_seg + bt->phase_seg1 + bt->phase_seg2;
98}
99
100/*
101 * get_can_dlc(value) - helper macro to cast a given data length code (dlc)
102 * to u8 and ensure the dlc value to be max. 8 bytes.
103 *
104 * To be used in the CAN netdriver receive path to ensure conformance with
105 * ISO 11898-1 Chapter 8.4.2.3 (DLC field)
106 */
107#define get_can_dlc(i) (min_t(u8, (i), CAN_MAX_DLC))
108#define get_canfd_dlc(i) (min_t(u8, (i), CANFD_MAX_DLC))
109
110/* Check for outgoing skbs that have not been created by the CAN subsystem */
111static inline bool can_skb_headroom_valid(struct net_device *dev,
112 struct sk_buff *skb)
113{
114 /* af_packet creates a headroom of HH_DATA_MOD bytes which is fine */
115 if (WARN_ON_ONCE(skb_headroom(skb) < sizeof(struct can_skb_priv)))
116 return false;
117
118 /* af_packet does not apply CAN skb specific settings */
119 if (skb->ip_summed == CHECKSUM_NONE) {
120 /* init headroom */
121 can_skb_prv(skb)->ifindex = dev->ifindex;
122 can_skb_prv(skb)->skbcnt = 0;
123
124 skb->ip_summed = CHECKSUM_UNNECESSARY;
125
126 /* perform proper loopback on capable devices */
127 if (dev->flags & IFF_ECHO)
128 skb->pkt_type = PACKET_LOOPBACK;
129 else
130 skb->pkt_type = PACKET_HOST;
131
132 skb_reset_mac_header(skb);
133 skb_reset_network_header(skb);
134 skb_reset_transport_header(skb);
135 }
136
137 return true;
138}
139
140/* Drop a given socketbuffer if it does not contain a valid CAN frame. */
141static inline bool can_dropped_invalid_skb(struct net_device *dev,
142 struct sk_buff *skb)
143{
144 const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
145
146 if (skb->protocol == htons(ETH_P_CAN)) {
147 if (unlikely(skb->len != CAN_MTU ||
148 cfd->len > CAN_MAX_DLEN))
149 goto inval_skb;
150 } else if (skb->protocol == htons(ETH_P_CANFD)) {
151 if (unlikely(skb->len != CANFD_MTU ||
152 cfd->len > CANFD_MAX_DLEN))
153 goto inval_skb;
154 } else
155 goto inval_skb;
156
157 if (!can_skb_headroom_valid(dev, skb))
158 goto inval_skb;
159
160 return false;
161
162inval_skb:
163 kfree_skb(skb);
164 dev->stats.tx_dropped++;
165 return true;
166}
167
168static inline bool can_is_canfd_skb(const struct sk_buff *skb)
169{
170 /* the CAN specific type of skb is identified by its data length */
171 return skb->len == CANFD_MTU;
172}
173
174/* helper to define static CAN controller features at device creation time */
175static inline void can_set_static_ctrlmode(struct net_device *dev,
176 u32 static_mode)
177{
178 struct can_priv *priv = netdev_priv(dev);
179
180 /* alloc_candev() succeeded => netdev_priv() is valid at this point */
181 priv->ctrlmode = static_mode;
182 priv->ctrlmode_static = static_mode;
183
184 /* override MTU which was set by default in can_setup()? */
185 if (static_mode & CAN_CTRLMODE_FD)
186 dev->mtu = CANFD_MTU;
187}
188
189/* get data length from can_dlc with sanitized can_dlc */
190u8 can_dlc2len(u8 can_dlc);
191
192/* map the sanitized data length to an appropriate data length code */
193u8 can_len2dlc(u8 len);
194
195struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
196 unsigned int txqs, unsigned int rxqs);
197#define alloc_candev(sizeof_priv, echo_skb_max) \
198 alloc_candev_mqs(sizeof_priv, echo_skb_max, 1, 1)
199#define alloc_candev_mq(sizeof_priv, echo_skb_max, count) \
200 alloc_candev_mqs(sizeof_priv, echo_skb_max, count, count)
201void free_candev(struct net_device *dev);
202
203/* a candev safe wrapper around netdev_priv */
204struct can_priv *safe_candev_priv(struct net_device *dev);
205
206int open_candev(struct net_device *dev);
207void close_candev(struct net_device *dev);
208int can_change_mtu(struct net_device *dev, int new_mtu);
209
210int register_candev(struct net_device *dev);
211void unregister_candev(struct net_device *dev);
212
213int can_restart_now(struct net_device *dev);
214void can_bus_off(struct net_device *dev);
215
216void can_change_state(struct net_device *dev, struct can_frame *cf,
217 enum can_state tx_state, enum can_state rx_state);
218
219int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
220 unsigned int idx);
221struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx,
222 u8 *len_ptr);
223unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx);
224void can_free_echo_skb(struct net_device *dev, unsigned int idx);
225
226#ifdef CONFIG_OF
227void of_can_transceiver(struct net_device *dev);
228#else
229static inline void of_can_transceiver(struct net_device *dev) { }
230#endif
231
232struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);
233struct sk_buff *alloc_canfd_skb(struct net_device *dev,
234 struct canfd_frame **cfd);
235struct sk_buff *alloc_can_err_skb(struct net_device *dev,
236 struct can_frame **cf);
237
238#endif /* !_CAN_DEV_H */