linux/include/uapi/linux/can/netlink.h
Vincent Mailhol d99755f71a can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC)
Add the netlink interface for TDC parameters of struct can_tdc_const
and can_tdc.

Contrary to the can_bittiming(_const) structures for which there is
just a single IFLA_CAN(_DATA)_BITTMING(_CONST) entry per structure,
here, we create a nested entry IFLA_CAN_TDC. Within this nested entry,
additional IFLA_CAN_TDC_TDC* entries are added for each of the TDC
parameters of the newly introduced struct can_tdc_const and struct
can_tdc.

For struct can_tdc_const, these are:
        IFLA_CAN_TDC_TDCV_MIN
        IFLA_CAN_TDC_TDCV_MAX
        IFLA_CAN_TDC_TDCO_MIN
        IFLA_CAN_TDC_TDCO_MAX
        IFLA_CAN_TDC_TDCF_MIN
        IFLA_CAN_TDC_TDCF_MAX

For struct can_tdc, these are:
        IFLA_CAN_TDC_TDCV
        IFLA_CAN_TDC_TDCO
        IFLA_CAN_TDC_TDCF

This is done so that changes can be applied in the future to the
structures without breaking the netlink interface.

The TDC netlink logic works as follow:

 * CAN_CTRLMODE_FD is not provided:
    - if any TDC parameters are provided: error.

    - TDC parameters not provided: TDC parameters unchanged.

 * CAN_CTRLMODE_FD is provided and is false:
     - TDC is deactivated: both the structure and the
       CAN_CTRLMODE_TDC_{AUTO,MANUAL} flags are flushed.

 * CAN_CTRLMODE_FD provided and is true:
    - CAN_CTRLMODE_TDC_{AUTO,MANUAL} and tdc{v,o,f} not provided: call
      can_calc_tdco() to automatically decide whether TDC should be
      activated and, if so, set CAN_CTRLMODE_TDC_AUTO and uses the
      calculated tdco value.

    - CAN_CTRLMODE_TDC_AUTO and tdco provided: set
      CAN_CTRLMODE_TDC_AUTO and use the provided tdco value. Here,
      tdcv is illegal and tdcf is optional.

    - CAN_CTRLMODE_TDC_MANUAL and both of tdcv and tdco provided: set
      CAN_CTRLMODE_TDC_MANUAL and use the provided tdcv and tdco
      value. Here, tdcf is optional.

    - CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive. Whenever
      one flag is turned on, the other will automatically be turned
      off. Providing both returns an error.

    - Combination other than the one listed above are illegal and will
      return an error.

N.B. above rules mean that whenever CAN_CTRLMODE_FD is provided, the
previous TDC values will be overwritten. The only option to reuse
previous TDC value is to not provide CAN_CTRLMODE_FD.

All the new parameters are defined as u32. This arbitrary choice is
done to mimic the other bittiming values with are also all of type
u32. An u16 would have been sufficient to hold the TDC values.

This patch completes below series (c.f. [1]):
  - commit 289ea9e4ae59 ("can: add new CAN FD bittiming parameters:
    Transmitter Delay Compensation (TDC)")
  - commit c25cc7993243 ("can: bittiming: add calculation for CAN FD
    Transmitter Delay Compensation (TDC)")

[1] https://lore.kernel.org/linux-can/20210224002008.4158-1-mailhol.vincent@wanadoo.fr/T/#t

Link: https://lore.kernel.org/all/20210918095637.20108-5-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2021-10-24 16:24:29 +02:00

173 lines
4.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
/*
* linux/can/netlink.h
*
* Definitions for the CAN netlink interface
*
* Copyright (c) 2009 Wolfgang Grandegger <wg@grandegger.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the version 2 of the GNU General Public License
* as published by the Free Software Foundation
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _UAPI_CAN_NETLINK_H
#define _UAPI_CAN_NETLINK_H
#include <linux/types.h>
/*
* CAN bit-timing parameters
*
* For further information, please read chapter "8 BIT TIMING
* REQUIREMENTS" of the "Bosch CAN Specification version 2.0"
* at http://www.semiconductors.bosch.de/pdf/can2spec.pdf.
*/
struct can_bittiming {
__u32 bitrate; /* Bit-rate in bits/second */
__u32 sample_point; /* Sample point in one-tenth of a percent */
__u32 tq; /* Time quanta (TQ) in nanoseconds */
__u32 prop_seg; /* Propagation segment in TQs */
__u32 phase_seg1; /* Phase buffer segment 1 in TQs */
__u32 phase_seg2; /* Phase buffer segment 2 in TQs */
__u32 sjw; /* Synchronisation jump width in TQs */
__u32 brp; /* Bit-rate prescaler */
};
/*
* CAN hardware-dependent bit-timing constant
*
* Used for calculating and checking bit-timing parameters
*/
struct can_bittiming_const {
char name[16]; /* Name of the CAN controller hardware */
__u32 tseg1_min; /* Time segment 1 = prop_seg + phase_seg1 */
__u32 tseg1_max;
__u32 tseg2_min; /* Time segment 2 = phase_seg2 */
__u32 tseg2_max;
__u32 sjw_max; /* Synchronisation jump width */
__u32 brp_min; /* Bit-rate prescaler */
__u32 brp_max;
__u32 brp_inc;
};
/*
* CAN clock parameters
*/
struct can_clock {
__u32 freq; /* CAN system clock frequency in Hz */
};
/*
* CAN operational and error states
*/
enum can_state {
CAN_STATE_ERROR_ACTIVE = 0, /* RX/TX error count < 96 */
CAN_STATE_ERROR_WARNING, /* RX/TX error count < 128 */
CAN_STATE_ERROR_PASSIVE, /* RX/TX error count < 256 */
CAN_STATE_BUS_OFF, /* RX/TX error count >= 256 */
CAN_STATE_STOPPED, /* Device is stopped */
CAN_STATE_SLEEPING, /* Device is sleeping */
CAN_STATE_MAX
};
/*
* CAN bus error counters
*/
struct can_berr_counter {
__u16 txerr;
__u16 rxerr;
};
/*
* CAN controller mode
*/
struct can_ctrlmode {
__u32 mask;
__u32 flags;
};
#define CAN_CTRLMODE_LOOPBACK 0x01 /* Loopback mode */
#define CAN_CTRLMODE_LISTENONLY 0x02 /* Listen-only mode */
#define CAN_CTRLMODE_3_SAMPLES 0x04 /* Triple sampling mode */
#define CAN_CTRLMODE_ONE_SHOT 0x08 /* One-Shot mode */
#define CAN_CTRLMODE_BERR_REPORTING 0x10 /* Bus-error reporting */
#define CAN_CTRLMODE_FD 0x20 /* CAN FD mode */
#define CAN_CTRLMODE_PRESUME_ACK 0x40 /* Ignore missing CAN ACKs */
#define CAN_CTRLMODE_FD_NON_ISO 0x80 /* CAN FD in non-ISO mode */
#define CAN_CTRLMODE_CC_LEN8_DLC 0x100 /* Classic CAN DLC option */
#define CAN_CTRLMODE_TDC_AUTO 0x200 /* CAN transiver automatically calculates TDCV */
#define CAN_CTRLMODE_TDC_MANUAL 0x400 /* TDCV is manually set up by user */
/*
* CAN device statistics
*/
struct can_device_stats {
__u32 bus_error; /* Bus errors */
__u32 error_warning; /* Changes to error warning state */
__u32 error_passive; /* Changes to error passive state */
__u32 bus_off; /* Changes to bus off state */
__u32 arbitration_lost; /* Arbitration lost errors */
__u32 restarts; /* CAN controller re-starts */
};
/*
* CAN netlink interface
*/
enum {
IFLA_CAN_UNSPEC,
IFLA_CAN_BITTIMING,
IFLA_CAN_BITTIMING_CONST,
IFLA_CAN_CLOCK,
IFLA_CAN_STATE,
IFLA_CAN_CTRLMODE,
IFLA_CAN_RESTART_MS,
IFLA_CAN_RESTART,
IFLA_CAN_BERR_COUNTER,
IFLA_CAN_DATA_BITTIMING,
IFLA_CAN_DATA_BITTIMING_CONST,
IFLA_CAN_TERMINATION,
IFLA_CAN_TERMINATION_CONST,
IFLA_CAN_BITRATE_CONST,
IFLA_CAN_DATA_BITRATE_CONST,
IFLA_CAN_BITRATE_MAX,
IFLA_CAN_TDC,
/* add new constants above here */
__IFLA_CAN_MAX,
IFLA_CAN_MAX = __IFLA_CAN_MAX - 1
};
/*
* CAN FD Transmitter Delay Compensation (TDC)
*
* Please refer to struct can_tdc_const and can_tdc in
* include/linux/can/bittiming.h for further details.
*/
enum {
IFLA_CAN_TDC_UNSPEC,
IFLA_CAN_TDC_TDCV_MIN, /* u32 */
IFLA_CAN_TDC_TDCV_MAX, /* u32 */
IFLA_CAN_TDC_TDCO_MIN, /* u32 */
IFLA_CAN_TDC_TDCO_MAX, /* u32 */
IFLA_CAN_TDC_TDCF_MIN, /* u32 */
IFLA_CAN_TDC_TDCF_MAX, /* u32 */
IFLA_CAN_TDC_TDCV, /* u32 */
IFLA_CAN_TDC_TDCO, /* u32 */
IFLA_CAN_TDC_TDCF, /* u32 */
/* add new constants above here */
__IFLA_CAN_TDC,
IFLA_CAN_TDC_MAX = __IFLA_CAN_TDC - 1
};
/* u16 termination range: 1..65535 Ohms */
#define CAN_TERMINATION_DISABLED 0
#endif /* !_UAPI_CAN_NETLINK_H */