1 /* SPDX-License-Identifier: GPL-2.0-only */ 1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* Copyright (c) 2020 Pengutronix, Marc Kleine 2 /* Copyright (c) 2020 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
3 * Copyright (c) 2021 Vincent Mailhol <mailhol 3 * Copyright (c) 2021 Vincent Mailhol <mailhol.vincent@wanadoo.fr>
4 */ 4 */
5 5
6 #ifndef _CAN_BITTIMING_H 6 #ifndef _CAN_BITTIMING_H
7 #define _CAN_BITTIMING_H 7 #define _CAN_BITTIMING_H
8 8
9 #include <linux/netdevice.h> 9 #include <linux/netdevice.h>
10 #include <linux/can/netlink.h> 10 #include <linux/can/netlink.h>
11 11
12 #define CAN_SYNC_SEG 1 12 #define CAN_SYNC_SEG 1
13 13
14 #define CAN_BITRATE_UNSET 0 <<
15 #define CAN_BITRATE_UNKNOWN (-1U) <<
16 14
17 #define CAN_CTRLMODE_TDC_MASK !! 15 /* Kilobits and Megabits per second */
18 (CAN_CTRLMODE_TDC_AUTO | CAN_CTRLMODE_ !! 16 #define CAN_KBPS 1000UL
>> 17 #define CAN_MBPS 1000000UL
>> 18
>> 19 /* Megahertz */
>> 20 #define CAN_MHZ 1000000UL
19 21
20 /* 22 /*
21 * struct can_tdc - CAN FD Transmission Delay 23 * struct can_tdc - CAN FD Transmission Delay Compensation parameters
22 * 24 *
23 * At high bit rates, the propagation delay fr 25 * At high bit rates, the propagation delay from the TX pin to the RX
24 * pin of the transceiver causes measurement e 26 * pin of the transceiver causes measurement errors: the sample point
25 * on the RX pin might occur on the previous b 27 * on the RX pin might occur on the previous bit.
26 * 28 *
27 * To solve this issue, ISO 11898-1 introduces 29 * To solve this issue, ISO 11898-1 introduces in section 11.3.3
28 * "Transmitter delay compensation" a SSP (Sec 30 * "Transmitter delay compensation" a SSP (Secondary Sample Point)
29 * equal to the distance from the start of the !! 31 * equal to the distance, in time quanta, from the start of the bit
30 * to the actual measurement on the RX pin. !! 32 * time on the TX pin to the actual measurement on the RX pin.
31 * 33 *
32 * This structure contains the parameters to c 34 * This structure contains the parameters to calculate that SSP.
33 * 35 *
34 * -+----------- one bit ----------+-- TX pin !! 36 * @tdcv: Transmitter Delay Compensation Value. Distance, in time
35 * |<--- Sample Point --->| !! 37 * quanta, from when the bit is sent on the TX pin to when it is
>> 38 * received on the RX pin of the transmitter. Possible options:
>> 39 *
>> 40 * O: automatic mode. The controller dynamically measure @tdcv
>> 41 * for each transmitted CAN FD frame.
>> 42 *
>> 43 * Other values: manual mode. Use the fixed provided value.
>> 44 *
>> 45 * @tdco: Transmitter Delay Compensation Offset. Offset value, in time
>> 46 * quanta, defining the distance between the start of the bit
>> 47 * reception on the RX pin of the transceiver and the SSP
>> 48 * position such as SSP = @tdcv + @tdco.
36 * 49 *
37 * --+----------- one !! 50 * If @tdco is zero, then TDC is disabled and both @tdcv and
38 * |<-------- TDCV -------->| !! 51 * @tdcf should be ignored.
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 * 52 *
70 * @tdcf: Transmitter Delay Compensation Filte 53 * @tdcf: Transmitter Delay Compensation Filter window. Defines the
71 * minimum value for the SSP position in !! 54 * minimum value for the SSP position in time quanta. If SSP is
72 * SSP position is less than @tdcf, then !! 55 * less than @tdcf, then no delay compensations occur and the
73 * occur and the normal sampling point is !! 56 * normal sampling point is used instead. The feature is enabled
74 * feature is enabled if and only if @tdc !! 57 * if and only if @tdcv is set to zero (automatic mode) and @tdcf
75 * (automatic mode) and @tdcf is configur !! 58 * is configured to a value greater than @tdco.
76 * than @tdco. <<
77 */ 59 */
78 struct can_tdc { 60 struct can_tdc {
79 u32 tdcv; 61 u32 tdcv;
80 u32 tdco; 62 u32 tdco;
81 u32 tdcf; 63 u32 tdcf;
82 }; 64 };
83 65
84 /* 66 /*
85 * struct can_tdc_const - CAN hardware-depende 67 * struct can_tdc_const - CAN hardware-dependent constant for
86 * Transmission Delay Compensation 68 * Transmission Delay Compensation
87 * 69 *
88 * @tdcv_min: Transmitter Delay Compensation V !! 70 * @tdcv_max: Transmitter Delay Compensation Value maximum value.
89 * the controller does not support manual !! 71 * Should be set to zero if the controller does not support
90 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) th !! 72 * manual mode for tdcv.
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 73 * @tdco_max: Transmitter Delay Compensation Offset maximum value.
99 * Should not be zero. If the controller 74 * Should not be zero. If the controller does not support TDC,
100 * then the pointer to this structure sho 75 * then the pointer to this structure should be NULL.
101 * <<
102 * @tdcf_min: Transmitter Delay Compensation F <<
103 * value. If @tdcf_max is zero, this valu <<
104 * @tdcf_max: Transmitter Delay Compensation F 76 * @tdcf_max: Transmitter Delay Compensation Filter window maximum
105 * value. Should be set to zero if the co 77 * value. Should be set to zero if the controller does not
106 * support this feature. 78 * support this feature.
107 */ 79 */
108 struct can_tdc_const { 80 struct can_tdc_const {
109 u32 tdcv_min; <<
110 u32 tdcv_max; 81 u32 tdcv_max;
111 u32 tdco_min; <<
112 u32 tdco_max; 82 u32 tdco_max;
113 u32 tdcf_min; <<
114 u32 tdcf_max; 83 u32 tdcf_max;
115 }; 84 };
116 85
117 #ifdef CONFIG_CAN_CALC_BITTIMING 86 #ifdef CONFIG_CAN_CALC_BITTIMING
118 int can_calc_bittiming(const struct net_device !! 87 int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
119 const struct can_bittim !! 88 const struct can_bittiming_const *btc);
120 89
121 void can_calc_tdco(struct can_tdc *tdc, const !! 90 void can_calc_tdco(struct net_device *dev);
122 const struct can_bittiming <<
123 u32 *ctrlmode, u32 ctrlmode <<
124 #else /* !CONFIG_CAN_CALC_BITTIMING */ 91 #else /* !CONFIG_CAN_CALC_BITTIMING */
125 static inline int 92 static inline int
126 can_calc_bittiming(const struct net_device *de !! 93 can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
127 const struct can_bittiming_ !! 94 const struct can_bittiming_const *btc)
128 { 95 {
129 netdev_err(dev, "bit-timing calculatio 96 netdev_err(dev, "bit-timing calculation not available\n");
130 return -EINVAL; 97 return -EINVAL;
131 } 98 }
132 99
133 static inline void !! 100 static inline void can_calc_tdco(struct net_device *dev)
134 can_calc_tdco(struct can_tdc *tdc, const struc <<
135 const struct can_bittiming *dbt, <<
136 u32 *ctrlmode, u32 ctrlmode_supp <<
137 { 101 {
138 } 102 }
139 #endif /* CONFIG_CAN_CALC_BITTIMING */ 103 #endif /* CONFIG_CAN_CALC_BITTIMING */
140 104
141 void can_sjw_set_default(struct can_bittiming !! 105 int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
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 106 const struct can_bittiming_const *btc,
148 const u32 *bitrate_const 107 const u32 *bitrate_const,
149 const unsigned int bitra !! 108 const unsigned int bitrate_const_cnt);
150 struct netlink_ext_ack * <<
151 109
152 /* 110 /*
153 * can_bit_time() - Duration of one bit 111 * can_bit_time() - Duration of one bit
154 * 112 *
155 * Please refer to ISO 11898-1:2015, section 1 113 * Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for
156 * additional information. 114 * additional information.
157 * 115 *
158 * Return: the number of time quanta in one bi 116 * Return: the number of time quanta in one bit.
159 */ 117 */
160 static inline unsigned int can_bit_time(const 118 static inline unsigned int can_bit_time(const struct can_bittiming *bt)
161 { 119 {
162 return CAN_SYNC_SEG + bt->prop_seg + b 120 return CAN_SYNC_SEG + bt->prop_seg + bt->phase_seg1 + bt->phase_seg2;
163 } 121 }
164 122
165 #endif /* !_CAN_BITTIMING_H */ 123 #endif /* !_CAN_BITTIMING_H */
166 124
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