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 14 #define CAN_BITRATE_UNSET 0
15 #define CAN_BITRATE_UNKNOWN (-1U) 15 #define CAN_BITRATE_UNKNOWN (-1U)
16 16
17 #define CAN_CTRLMODE_TDC_MASK 17 #define CAN_CTRLMODE_TDC_MASK \
18 (CAN_CTRLMODE_TDC_AUTO | CAN_CTRLMODE_ 18 (CAN_CTRLMODE_TDC_AUTO | CAN_CTRLMODE_TDC_MANUAL)
19 19
20 /* 20 /*
21 * struct can_tdc - CAN FD Transmission Delay 21 * struct can_tdc - CAN FD Transmission Delay Compensation parameters
22 * 22 *
23 * At high bit rates, the propagation delay fr 23 * At high bit rates, the propagation delay from the TX pin to the RX
24 * pin of the transceiver causes measurement e 24 * pin of the transceiver causes measurement errors: the sample point
25 * on the RX pin might occur on the previous b 25 * on the RX pin might occur on the previous bit.
26 * 26 *
27 * To solve this issue, ISO 11898-1 introduces 27 * To solve this issue, ISO 11898-1 introduces in section 11.3.3
28 * "Transmitter delay compensation" a SSP (Sec 28 * "Transmitter delay compensation" a SSP (Secondary Sample Point)
29 * equal to the distance from the start of the 29 * equal to the distance from the start of the bit time on the TX pin
30 * to the actual measurement on the RX pin. 30 * to the actual measurement on the RX pin.
31 * 31 *
32 * This structure contains the parameters to c 32 * This structure contains the parameters to calculate that SSP.
33 * 33 *
34 * -+----------- one bit ----------+-- TX pin 34 * -+----------- one bit ----------+-- TX pin
35 * |<--- Sample Point --->| 35 * |<--- Sample Point --->|
36 * 36 *
37 * --+----------- one 37 * --+----------- one bit ----------+-- RX pin
38 * |<-------- TDCV -------->| 38 * |<-------- TDCV -------->|
39 * |<------- TDCO -- 39 * |<------- TDCO ------->|
40 * |<----------- Secondary Sample Point ----- 40 * |<----------- Secondary Sample Point ---------->|
41 * 41 *
42 * To increase precision, contrary to the othe 42 * To increase precision, contrary to the other bittiming parameters
43 * which are measured in time quanta, the TDC 43 * which are measured in time quanta, the TDC parameters are measured
44 * in clock periods (also referred as "minimum 44 * in clock periods (also referred as "minimum time quantum" in ISO
45 * 11898-1). 45 * 11898-1).
46 * 46 *
47 * @tdcv: Transmitter Delay Compensation Value 47 * @tdcv: Transmitter Delay Compensation Value. The time needed for
48 * the signal to propagate, i.e. the dist 48 * the signal to propagate, i.e. the distance, in clock periods,
49 * from the start of the bit on the TX pi 49 * 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 50 * on the RX pin. @tdcv depends on the controller modes:
51 * 51 *
52 * CAN_CTRLMODE_TDC_AUTO is set: The tr 52 * CAN_CTRLMODE_TDC_AUTO is set: The transceiver dynamically
53 * measures @tdcv for each transmitted 53 * measures @tdcv for each transmitted CAN FD frame and the
54 * value provided here should be ignore 54 * value provided here should be ignored.
55 * 55 *
56 * CAN_CTRLMODE_TDC_MANUAL is set: use 56 * CAN_CTRLMODE_TDC_MANUAL is set: use the fixed provided @tdcv
57 * value. 57 * value.
58 * 58 *
59 * N.B. CAN_CTRLMODE_TDC_AUTO and CAN_CTR 59 * N.B. CAN_CTRLMODE_TDC_AUTO and CAN_CTRLMODE_TDC_MANUAL are
60 * mutually exclusive. Only one can be se 60 * mutually exclusive. Only one can be set at a time. If both
61 * CAN_TDC_CTRLMODE_AUTO and CAN_TDC_CTRL 61 * CAN_TDC_CTRLMODE_AUTO and CAN_TDC_CTRLMODE_MANUAL are unset,
62 * TDC is disabled and all the values of 62 * TDC is disabled and all the values of this structure should be
63 * ignored. 63 * ignored.
64 * 64 *
65 * @tdco: Transmitter Delay Compensation Offse 65 * @tdco: Transmitter Delay Compensation Offset. Offset value, in
66 * clock periods, defining the distance b 66 * clock periods, defining the distance between the start of the
67 * bit reception on the RX pin of the tra 67 * bit reception on the RX pin of the transceiver and the SSP
68 * position such that SSP = @tdcv + @tdco 68 * position such that SSP = @tdcv + @tdco.
69 * 69 *
70 * @tdcf: Transmitter Delay Compensation Filte 70 * @tdcf: Transmitter Delay Compensation Filter window. Defines the
71 * minimum value for the SSP position in 71 * minimum value for the SSP position in clock periods. If the
72 * SSP position is less than @tdcf, then 72 * SSP position is less than @tdcf, then no delay compensations
73 * occur and the normal sampling point is 73 * occur and the normal sampling point is used instead. The
74 * feature is enabled if and only if @tdc 74 * feature is enabled if and only if @tdcv is set to zero
75 * (automatic mode) and @tdcf is configur 75 * (automatic mode) and @tdcf is configured to a value greater
76 * than @tdco. 76 * than @tdco.
77 */ 77 */
78 struct can_tdc { 78 struct can_tdc {
79 u32 tdcv; 79 u32 tdcv;
80 u32 tdco; 80 u32 tdco;
81 u32 tdcf; 81 u32 tdcf;
82 }; 82 };
83 83
84 /* 84 /*
85 * struct can_tdc_const - CAN hardware-depende 85 * struct can_tdc_const - CAN hardware-dependent constant for
86 * Transmission Delay Compensation 86 * Transmission Delay Compensation
87 * 87 *
88 * @tdcv_min: Transmitter Delay Compensation V 88 * @tdcv_min: Transmitter Delay Compensation Value minimum value. If
89 * the controller does not support manual 89 * the controller does not support manual mode for tdcv
90 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) th 90 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) then this value is
91 * ignored. 91 * ignored.
92 * @tdcv_max: Transmitter Delay Compensation V 92 * @tdcv_max: Transmitter Delay Compensation Value maximum value. If
93 * the controller does not support manual 93 * the controller does not support manual mode for tdcv
94 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) th 94 * (c.f. flag CAN_CTRLMODE_TDC_MANUAL) then this value is
95 * ignored. 95 * ignored.
96 * 96 *
97 * @tdco_min: Transmitter Delay Compensation O 97 * @tdco_min: Transmitter Delay Compensation Offset minimum value.
98 * @tdco_max: Transmitter Delay Compensation O 98 * @tdco_max: Transmitter Delay Compensation Offset maximum value.
99 * Should not be zero. If the controller 99 * Should not be zero. If the controller does not support TDC,
100 * then the pointer to this structure sho 100 * then the pointer to this structure should be NULL.
101 * 101 *
102 * @tdcf_min: Transmitter Delay Compensation F 102 * @tdcf_min: Transmitter Delay Compensation Filter window minimum
103 * value. If @tdcf_max is zero, this valu 103 * value. If @tdcf_max is zero, this value is ignored.
104 * @tdcf_max: Transmitter Delay Compensation F 104 * @tdcf_max: Transmitter Delay Compensation Filter window maximum
105 * value. Should be set to zero if the co 105 * value. Should be set to zero if the controller does not
106 * support this feature. 106 * support this feature.
107 */ 107 */
108 struct can_tdc_const { 108 struct can_tdc_const {
109 u32 tdcv_min; 109 u32 tdcv_min;
110 u32 tdcv_max; 110 u32 tdcv_max;
111 u32 tdco_min; 111 u32 tdco_min;
112 u32 tdco_max; 112 u32 tdco_max;
113 u32 tdcf_min; 113 u32 tdcf_min;
114 u32 tdcf_max; 114 u32 tdcf_max;
115 }; 115 };
116 116
117 #ifdef CONFIG_CAN_CALC_BITTIMING 117 #ifdef CONFIG_CAN_CALC_BITTIMING
118 int can_calc_bittiming(const struct net_device 118 int can_calc_bittiming(const struct net_device *dev, struct can_bittiming *bt,
119 const struct can_bittim !! 119 const struct can_bittiming_const *btc);
120 120
121 void can_calc_tdco(struct can_tdc *tdc, const 121 void can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const,
122 const struct can_bittiming 122 const struct can_bittiming *dbt,
123 u32 *ctrlmode, u32 ctrlmode 123 u32 *ctrlmode, u32 ctrlmode_supported);
124 #else /* !CONFIG_CAN_CALC_BITTIMING */ 124 #else /* !CONFIG_CAN_CALC_BITTIMING */
125 static inline int 125 static inline int
126 can_calc_bittiming(const struct net_device *de 126 can_calc_bittiming(const struct net_device *dev, struct can_bittiming *bt,
127 const struct can_bittiming_ !! 127 const struct can_bittiming_const *btc)
128 { 128 {
129 netdev_err(dev, "bit-timing calculatio 129 netdev_err(dev, "bit-timing calculation not available\n");
130 return -EINVAL; 130 return -EINVAL;
131 } 131 }
132 132
133 static inline void 133 static inline void
134 can_calc_tdco(struct can_tdc *tdc, const struc 134 can_calc_tdco(struct can_tdc *tdc, const struct can_tdc_const *tdc_const,
135 const struct can_bittiming *dbt, 135 const struct can_bittiming *dbt,
136 u32 *ctrlmode, u32 ctrlmode_supp 136 u32 *ctrlmode, u32 ctrlmode_supported)
137 { 137 {
138 } 138 }
139 #endif /* CONFIG_CAN_CALC_BITTIMING */ 139 #endif /* CONFIG_CAN_CALC_BITTIMING */
140 140
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 141 int can_get_bittiming(const struct net_device *dev, struct can_bittiming *bt,
147 const struct can_bittimi 142 const struct can_bittiming_const *btc,
148 const u32 *bitrate_const 143 const u32 *bitrate_const,
149 const unsigned int bitra !! 144 const unsigned int bitrate_const_cnt);
150 struct netlink_ext_ack * <<
151 145
152 /* 146 /*
153 * can_bit_time() - Duration of one bit 147 * can_bit_time() - Duration of one bit
154 * 148 *
155 * Please refer to ISO 11898-1:2015, section 1 149 * Please refer to ISO 11898-1:2015, section 11.3.1.1 "Bit time" for
156 * additional information. 150 * additional information.
157 * 151 *
158 * Return: the number of time quanta in one bi 152 * Return: the number of time quanta in one bit.
159 */ 153 */
160 static inline unsigned int can_bit_time(const 154 static inline unsigned int can_bit_time(const struct can_bittiming *bt)
161 { 155 {
162 return CAN_SYNC_SEG + bt->prop_seg + b 156 return CAN_SYNC_SEG + bt->prop_seg + bt->phase_seg1 + bt->phase_seg2;
163 } 157 }
164 158
165 #endif /* !_CAN_BITTIMING_H */ 159 #endif /* !_CAN_BITTIMING_H */
166 160
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