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 #define CAN_CTRLMODE_TDC_MASK \
18 (CAN_CTRLMODE_TDC_AUTO | CAN_CTRLMODE_ 16 (CAN_CTRLMODE_TDC_AUTO | CAN_CTRLMODE_TDC_MANUAL)
19 17
20 /* 18 /*
21 * struct can_tdc - CAN FD Transmission Delay 19 * struct can_tdc - CAN FD Transmission Delay Compensation parameters
22 * 20 *
23 * At high bit rates, the propagation delay fr 21 * At high bit rates, the propagation delay from the TX pin to the RX
24 * pin of the transceiver causes measurement e 22 * pin of the transceiver causes measurement errors: the sample point
25 * on the RX pin might occur on the previous b 23 * on the RX pin might occur on the previous bit.
26 * 24 *
27 * To solve this issue, ISO 11898-1 introduces 25 * To solve this issue, ISO 11898-1 introduces in section 11.3.3
28 * "Transmitter delay compensation" a SSP (Sec 26 * "Transmitter delay compensation" a SSP (Secondary Sample Point)
29 * equal to the distance from the start of the 27 * equal to the distance from the start of the bit time on the TX pin
30 * to the actual measurement on the RX pin. 28 * to the actual measurement on the RX pin.
31 * 29 *
32 * This structure contains the parameters to c 30 * This structure contains the parameters to calculate that SSP.
33 * 31 *
34 * -+----------- one bit ----------+-- TX pin 32 * -+----------- one bit ----------+-- TX pin
35 * |<--- Sample Point --->| 33 * |<--- Sample Point --->|
36 * 34 *
37 * --+----------- one 35 * --+----------- one bit ----------+-- RX pin
38 * |<-------- TDCV -------->| 36 * |<-------- TDCV -------->|
39 * |<------- TDCO -- 37 * |<------- TDCO ------->|
40 * |<----------- Secondary Sample Point ----- 38 * |<----------- Secondary Sample Point ---------->|
41 * 39 *
42 * To increase precision, contrary to the othe 40 * To increase precision, contrary to the other bittiming parameters
43 * which are measured in time quanta, the TDC 41 * which are measured in time quanta, the TDC parameters are measured
44 * in clock periods (also referred as "minimum 42 * in clock periods (also referred as "minimum time quantum" in ISO
45 * 11898-1). 43 * 11898-1).
46 * 44 *
47 * @tdcv: Transmitter Delay Compensation Value 45 * @tdcv: Transmitter Delay Compensation Value. The time needed for
48 * the signal to propagate, i.e. the dist 46 * the signal to propagate, i.e. the distance, in clock periods,
49 * from the start of the bit on the TX pi 47 * from the start of the bit on the TX pin to when it is received
50 * on the RX pin. @tdcv depends on the co 48 * on the RX pin. @tdcv depends on the controller modes:
51 * 49 *
52 * CAN_CTRLMODE_TDC_AUTO is set: The tr 50 * CAN_CTRLMODE_TDC_AUTO is set: The transceiver dynamically
53 * measures @tdcv for each transmitted 51 * measures @tdcv for each transmitted CAN FD frame and the
54 * value provided here should be ignore 52 * value provided here should be ignored.
55 * 53 *
56 * CAN_CTRLMODE_TDC_MANUAL is set: use 54 * CAN_CTRLMODE_TDC_MANUAL is set: use the fixed provided @tdcv
57 * value. 55 * value.
58 * 56 *
59 * N.B. CAN_CTRLMODE_TDC_AUTO and CAN_CTR 57 * N.B. CAN_CTRLMODE_TDC_AUTO and CAN_CTRLMODE_TDC_MANUAL are
60 * mutually exclusive. Only one can be se 58 * mutually exclusive. Only one can be set at a time. If both
61 * CAN_TDC_CTRLMODE_AUTO and CAN_TDC_CTRL 59 * CAN_TDC_CTRLMODE_AUTO and CAN_TDC_CTRLMODE_MANUAL are unset,
62 * TDC is disabled and all the values of 60 * TDC is disabled and all the values of this structure should be
63 * ignored. 61 * ignored.
64 * 62 *
65 * @tdco: Transmitter Delay Compensation Offse 63 * @tdco: Transmitter Delay Compensation Offset. Offset value, in
66 * clock periods, defining the distance b 64 * clock periods, defining the distance between the start of the
67 * bit reception on the RX pin of the tra 65 * bit reception on the RX pin of the transceiver and the SSP
68 * position such that SSP = @tdcv + @tdco 66 * position such that SSP = @tdcv + @tdco.
69 * 67 *
70 * @tdcf: Transmitter Delay Compensation Filte 68 * @tdcf: Transmitter Delay Compensation Filter window. Defines the
71 * minimum value for the SSP position in 69 * minimum value for the SSP position in clock periods. If the
72 * SSP position is less than @tdcf, then 70 * SSP position is less than @tdcf, then no delay compensations
73 * occur and the normal sampling point is 71 * occur and the normal sampling point is used instead. The
74 * feature is enabled if and only if @tdc 72 * feature is enabled if and only if @tdcv is set to zero
75 * (automatic mode) and @tdcf is configur 73 * (automatic mode) and @tdcf is configured to a value greater
76 * than @tdco. 74 * than @tdco.
77 */ 75 */
78 struct can_tdc { 76 struct can_tdc {
79 u32 tdcv; 77 u32 tdcv;
80 u32 tdco; 78 u32 tdco;
81 u32 tdcf; 79 u32 tdcf;
82 }; 80 };
83 81
84 /* 82 /*
85 * struct can_tdc_const - CAN hardware-depende 83 * struct can_tdc_const - CAN hardware-dependent constant for
86 * Transmission Delay Compensation 84 * Transmission Delay Compensation
87 * 85 *
88 * @tdcv_min: Transmitter Delay Compensation V 86 * @tdcv_min: Transmitter Delay Compensation Value minimum value. If
89 * the controller does not support manual 87 * the controller does not support manual mode for tdcv
90 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) th 88 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) then this value is
91 * ignored. 89 * ignored.
92 * @tdcv_max: Transmitter Delay Compensation V 90 * @tdcv_max: Transmitter Delay Compensation Value maximum value. If
93 * the controller does not support manual 91 * the controller does not support manual mode for tdcv
94 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) th 92 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) then this value is
95 * ignored. 93 * ignored.
96 * 94 *
97 * @tdco_min: Transmitter Delay Compensation O 95 * @tdco_min: Transmitter Delay Compensation Offset minimum value.
98 * @tdco_max: Transmitter Delay Compensation O 96 * @tdco_max: Transmitter Delay Compensation Offset maximum value.
99 * Should not be zero. If the controller 97 * Should not be zero. If the controller does not support TDC,
100 * then the pointer to this structure sho 98 * then the pointer to this structure should be NULL.
101 * 99 *
102 * @tdcf_min: Transmitter Delay Compensation F 100 * @tdcf_min: Transmitter Delay Compensation Filter window minimum
103 * value. If @tdcf_max is zero, this valu 101 * value. If @tdcf_max is zero, this value is ignored.
104 * @tdcf_max: Transmitter Delay Compensation F 102 * @tdcf_max: Transmitter Delay Compensation Filter window maximum
105 * value. Should be set to zero if the co 103 * value. Should be set to zero if the controller does not
106 * support this feature. 104 * support this feature.
107 */ 105 */
108 struct can_tdc_const { 106 struct can_tdc_const {
109 u32 tdcv_min; 107 u32 tdcv_min;
110 u32 tdcv_max; 108 u32 tdcv_max;
111 u32 tdco_min; 109 u32 tdco_min;
112 u32 tdco_max; 110 u32 tdco_max;
113 u32 tdcf_min; 111 u32 tdcf_min;
114 u32 tdcf_max; 112 u32 tdcf_max;
115 }; 113 };
116 114
117 #ifdef CONFIG_CAN_CALC_BITTIMING 115 #ifdef CONFIG_CAN_CALC_BITTIMING
118 int can_calc_bittiming(const struct net_device 116 int can_calc_bittiming(const struct net_device *dev, struct can_bittiming *bt,
119 const struct can_bittim !! 117 const struct can_bittiming_const *btc);
120 118
121 void can_calc_tdco(struct can_tdc *tdc, const 119 void can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const,
122 const struct can_bittiming 120 const struct can_bittiming *dbt,
123 u32 *ctrlmode, u32 ctrlmode 121 u32 *ctrlmode, u32 ctrlmode_supported);
124 #else /* !CONFIG_CAN_CALC_BITTIMING */ 122 #else /* !CONFIG_CAN_CALC_BITTIMING */
125 static inline int 123 static inline int
126 can_calc_bittiming(const struct net_device *de 124 can_calc_bittiming(const struct net_device *dev, struct can_bittiming *bt,
127 const struct can_bittiming_ !! 125 const struct can_bittiming_const *btc)
128 { 126 {
129 netdev_err(dev, "bit-timing calculatio 127 netdev_err(dev, "bit-timing calculation not available\n");
130 return -EINVAL; 128 return -EINVAL;
131 } 129 }
132 130
133 static inline void 131 static inline void
134 can_calc_tdco(struct can_tdc *tdc, const struc 132 can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const,
135 const struct can_bittiming *dbt, 133 const struct can_bittiming *dbt,
136 u32 *ctrlmode, u32 ctrlmode_supp 134 u32 *ctrlmode, u32 ctrlmode_supported)
137 { 135 {
138 } 136 }
139 #endif /* CONFIG_CAN_CALC_BITTIMING */ 137 #endif /* CONFIG_CAN_CALC_BITTIMING */
140 138
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 139 int can_get_bittiming(const struct net_device *dev, struct can_bittiming *bt,
147 const struct can_bittimi 140 const struct can_bittiming_const *btc,
148 const u32 *bitrate_const 141 const u32 *bitrate_const,
149 const unsigned int bitra !! 142 const unsigned int bitrate_const_cnt);
150 struct netlink_ext_ack * <<
151 143
152 /* 144 /*
153 * can_bit_time() - Duration of one bit 145 * can_bit_time() - Duration of one bit
154 * 146 *
155 * Please refer to ISO 11898-1:2015, section 1 147 * Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for
156 * additional information. 148 * additional information.
157 * 149 *
158 * Return: the number of time quanta in one bi 150 * Return: the number of time quanta in one bit.
159 */ 151 */
160 static inline unsigned int can_bit_time(const 152 static inline unsigned int can_bit_time(const struct can_bittiming *bt)
161 { 153 {
162 return CAN_SYNC_SEG + bt->prop_seg + b 154 return CAN_SYNC_SEG + bt->prop_seg + bt->phase_seg1 + bt->phase_seg2;
163 } 155 }
164 156
165 #endif /* !_CAN_BITTIMING_H */ 157 #endif /* !_CAN_BITTIMING_H */
166 158
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