1 /* SPDX-License-Identifier: GPL-2.0-only */ 1
2 /* Copyright (c) 2020 Pengutronix, Marc Kleine
3 * Copyright (c) 2021 Vincent Mailhol <mailhol
4 */
5
6 #ifndef _CAN_BITTIMING_H
7 #define _CAN_BITTIMING_H
8
9 #include <linux/netdevice.h>
10 #include <linux/can/netlink.h>
11
12 #define CAN_SYNC_SEG 1
13
14 #define CAN_BITRATE_UNSET 0
15 #define CAN_BITRATE_UNKNOWN (-1U)
16
17 #define CAN_CTRLMODE_TDC_MASK
18 (CAN_CTRLMODE_TDC_AUTO | CAN_CTRLMODE_
19
20 /*
21 * struct can_tdc - CAN FD Transmission Delay
22 *
23 * At high bit rates, the propagation delay fr
24 * pin of the transceiver causes measurement e
25 * on the RX pin might occur on the previous b
26 *
27 * To solve this issue, ISO 11898-1 introduces
28 * "Transmitter delay compensation" a SSP (Sec
29 * equal to the distance from the start of the
30 * to the actual measurement on the RX pin.
31 *
32 * This structure contains the parameters to c
33 *
34 * -+----------- one bit ----------+-- TX pin
35 * |<--- Sample Point --->|
36 *
37 * --+----------- one
38 * |<-------- TDCV -------->|
39 * |<------- TDCO --
40 * |<----------- Secondary Sample Point -----
41 *
42 * To increase precision, contrary to the othe
43 * which are measured in time quanta, the TDC
44 * in clock periods (also referred as "minimum
45 * 11898-1).
46 *
47 * @tdcv: Transmitter Delay Compensation Value
48 * the signal to propagate, i.e. the dist
49 * from the start of the bit on the TX pi
50 * on the RX pin. @tdcv depends on the co
51 *
52 * CAN_CTRLMODE_TDC_AUTO is set: The tr
53 * measures @tdcv for each transmitted
54 * value provided here should be ignore
55 *
56 * CAN_CTRLMODE_TDC_MANUAL is set: use
57 * value.
58 *
59 * N.B. CAN_CTRLMODE_TDC_AUTO and CAN_CTR
60 * mutually exclusive. Only one can be se
61 * CAN_TDC_CTRLMODE_AUTO and CAN_TDC_CTRL
62 * TDC is disabled and all the values of
63 * ignored.
64 *
65 * @tdco: Transmitter Delay Compensation Offse
66 * clock periods, defining the distance b
67 * bit reception on the RX pin of the tra
68 * position such that SSP = @tdcv + @tdco
69 *
70 * @tdcf: Transmitter Delay Compensation Filte
71 * minimum value for the SSP position in
72 * SSP position is less than @tdcf, then
73 * occur and the normal sampling point is
74 * feature is enabled if and only if @tdc
75 * (automatic mode) and @tdcf is configur
76 * than @tdco.
77 */
78 struct can_tdc {
79 u32 tdcv;
80 u32 tdco;
81 u32 tdcf;
82 };
83
84 /*
85 * struct can_tdc_const - CAN hardware-depende
86 * Transmission Delay Compensation
87 *
88 * @tdcv_min: Transmitter Delay Compensation V
89 * the controller does not support manual
90 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) th
91 * ignored.
92 * @tdcv_max: Transmitter Delay Compensation V
93 * the controller does not support manual
94 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) th
95 * ignored.
96 *
97 * @tdco_min: Transmitter Delay Compensation O
98 * @tdco_max: Transmitter Delay Compensation O
99 * Should not be zero. If the controller
100 * then the pointer to this structure sho
101 *
102 * @tdcf_min: Transmitter Delay Compensation F
103 * value. If @tdcf_max is zero, this valu
104 * @tdcf_max: Transmitter Delay Compensation F
105 * value. Should be set to zero if the co
106 * support this feature.
107 */
108 struct can_tdc_const {
109 u32 tdcv_min;
110 u32 tdcv_max;
111 u32 tdco_min;
112 u32 tdco_max;
113 u32 tdcf_min;
114 u32 tdcf_max;
115 };
116
117 #ifdef CONFIG_CAN_CALC_BITTIMING
118 int can_calc_bittiming(const struct net_device
119 const struct can_bittim
120
121 void can_calc_tdco(struct can_tdc *tdc, const
122 const struct can_bittiming
123 u32 *ctrlmode, u32 ctrlmode
124 #else /* !CONFIG_CAN_CALC_BITTIMING */
125 static inline int
126 can_calc_bittiming(const struct net_device *de
127 const struct can_bittiming_
128 {
129 netdev_err(dev, "bit-timing calculatio
130 return -EINVAL;
131 }
132
133 static inline void
134 can_calc_tdco(struct can_tdc *tdc, const struc
135 const struct can_bittiming *dbt,
136 u32 *ctrlmode, u32 ctrlmode_supp
137 {
138 }
139 #endif /* CONFIG_CAN_CALC_BITTIMING */
140
141 void can_sjw_set_default(struct can_bittiming
142
143 int can_sjw_check(const struct net_device *dev
144 const struct can_bittiming_c
145
146 int can_get_bittiming(const struct net_device
147 const struct can_bittimi
148 const u32 *bitrate_const
149 const unsigned int bitra
150 struct netlink_ext_ack *
151
152 /*
153 * can_bit_time() - Duration of one bit
154 *
155 * Please refer to ISO 11898-1:2015, section 1
156 * additional information.
157 *
158 * Return: the number of time quanta in one bi
159 */
160 static inline unsigned int can_bit_time(const
161 {
162 return CAN_SYNC_SEG + bt->prop_seg + b
163 }
164
165 #endif /* !_CAN_BITTIMING_H */
166
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