linux-toradex.git/include/uapi/linux/can, branch v5.19-rc7

can: isotp: add support for transmission without flow control

2022-05-16T20:03:45+00:00

Usually the ISO 15765-2 protocol is a point-to-point protocol to transfer
segmented PDUs to a dedicated receiver. This receiver sends a flow control
message to specify protocol options and timings (e.g. block size / STmin).

The so called functional addressing communication allows a 1:N
communication but is limited to a single frame length.

This new CAN_ISOTP_CF_BROADCAST allows an unconfirmed 1:N communication
with PDU length that would not fit into a single frame. This feature is
not covered by the ISO 15765-2 standard.

Link: https://lore.kernel.org/all/20220507115558.19065-1-socketcan@hartkopp.net
Signed-off-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: isotp: set default value for N_As to 50 micro seconds

2022-03-10T08:23:45+00:00

The N_As value describes the time a CAN frame needs on the wire when
transmitted by the CAN controller. Even very short CAN FD frames need
arround 100 usecs (bitrate 1Mbit/s, data bitrate 8Mbit/s).

Having N_As to be zero (the former default) leads to 'no CAN frame
separation' when STmin is set to zero by the receiving node. This 'burst
mode' should not be enabled by default as it could potentially dump a high
number of CAN frames into the netdev queue from the soft hrtimer context.
This does not affect the system stability but is just not nice and
cooperative.

With this N_As/frame_txtime value the 'burst mode' is disabled by default.

As user space applications usually do not set the frame_txtime element
of struct can_isotp_options the new in-kernel default is very likely
overwritten with zero when the sockopt() CAN_ISOTP_OPTS is invoked.
To make sure that a N_As value of zero is only set intentional the
value '0' is now interpreted as 'do not change the current value'.
When a frame_txtime of zero is required for testing purposes this
CAN_ISOTP_FRAME_TXTIME_ZERO u32 value has to be set in frame_txtime.

Link: https://lore.kernel.org/all/20220309120416.83514-2-socketcan@hartkopp.net
Signed-off-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: netlink: report the CAN controller mode supported flags

2022-01-05T11:09:06+00:00

Currently, the CAN netlink interface provides no easy ways to check
the capabilities of a given controller. The only method from the
command line is to try each CAN_CTRLMODE_* individually to check
whether the netlink interface returns an -EOPNOTSUPP error or not
(alternatively, one may find it easier to directly check the source
code of the driver instead...)

This patch introduces a method for the user to check both the
supported and the static capabilities. The proposed method introduces
a new IFLA nest: IFLA_CAN_CTRLMODE_EXT which extends the current
IFLA_CAN_CTRLMODE. This is done to guaranty a full forward and
backward compatibility between the kernel and the user land
applications.

The IFLA_CAN_CTRLMODE_EXT nest contains one single entry:
IFLA_CAN_CTRLMODE_SUPPORTED. Because this entry is only used in one
direction: kernel to userland, no new struct nla_policy are
introduced.

Below table explains how IFLA_CAN_CTRLMODE_SUPPORTED (hereafter:
"supported") and can_ctrlmode::flags (hereafter: "flags") allow us to
identify both the supported and the static capabilities, when masked
with any of the CAN_CTRLMODE_* bit flags:

 supported &	flags &		Controller capabilities
 CAN_CTRLMODE_*	CAN_CTRLMODE_*
 -----------------------------------------------------------------------
 false		false		Feature not supported (always disabled)
 false		true		Static feature (always enabled)
 true		false		Feature supported but disabled
 true		true		Feature supported and enabled

Link: https://lore.kernel.org/all/20211213160226.56219-5-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC)

2021-10-24T14:24:29+00:00

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 
Signed-off-by: Marc Kleine-Budde

can: bittiming: allow TDC{V,O} to be zero and add can_tdc_const::tdc{v,o,f}_min

2021-10-24T14:24:28+00:00

ISO 11898-1 specifies in section 11.3.3 "Transmitter delay
compensation" that "the configuration range for [the] SSP position
shall be at least 0 to 63 minimum time quanta."

Because SSP = TDCV + TDCO, it means that we should allow both TDCV and
TDCO to hold zero value in order to honor SSP's minimum possible
value.

However, current implementation assigned special meaning to TDCV and
TDCO's zero values:
  * TDCV = 0 -> TDCV is automatically measured by the transceiver.
  * TDCO = 0 -> TDC is off.

In order to allow for those values to really be zero and to maintain
current features, we introduce two new flags:
  * CAN_CTRLMODE_TDC_AUTO indicates that the controller support
    automatic measurement of TDCV.
  * CAN_CTRLMODE_TDC_MANUAL indicates that the controller support
    manual configuration of TDCV. N.B.: current implementation failed
    to provide an option for the driver to indicate that only manual
    mode was supported.

TDC is disabled if both CAN_CTRLMODE_TDC_AUTO and
CAN_CTRLMODE_TDC_MANUAL flags are off, c.f. the helper function
can_tdc_is_enabled() which is also introduced in this patch.

Also, this patch adds three fields: tdcv_min, tdco_min and tdcf_min to
struct can_tdc_const. While we are not convinced that those three
fields could be anything else than zero, we can imagine that some
controllers might specify a lower bound on these. Thus, those minimums
are really added "just in case".

Comments of struct can_tdc and can_tdc_const are updated accordingly.

Finally, the changes are applied to the etas_es58x driver.

Link: https://lore.kernel.org/all/20210918095637.20108-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol 
Signed-off-by: Marc Kleine-Budde

can: j1939: extend UAPI to notify about RX status

2021-08-04T10:11:52+00:00

To be able to create applications with user friendly feedback, we need be
able to provide receive status information.

Typical ETP transfer may take seconds or even hours. To give user some
clue or show a progress bar, the stack should push status updates.
Same as for the TX information, the socket error queue will be used with
following new signals:
- J1939_EE_INFO_RX_RTS   - received and accepted request to send signal.
- J1939_EE_INFO_RX_DPO   - received data package offset signal
- J1939_EE_INFO_RX_ABORT - RX session was aborted

Instead of completion signal, user will get data package.
To activate this signals, application should set
SOF_TIMESTAMPING_RX_SOFTWARE to the SO_TIMESTAMPING socket option. This
will avoid unpredictable application behavior for the old software.

Link: https://lore.kernel.org/r/20210707094854.30781-3-o.rempel@pengutronix.de
Signed-off-by: Oleksij Rempel 
Signed-off-by: Marc Kleine-Budde

can: isotp: add SF_BROADCAST support for functional addressing

2020-12-10T08:31:40+00:00

When CAN_ISOTP_SF_BROADCAST is set in the CAN_ISOTP_OPTS flags the CAN_ISOTP
socket is switched into functional addressing mode, where only single frame
(SF) protocol data units can be send on the specified CAN interface and the
given tp.tx_id after bind().

In opposite to normal and extended addressing this socket does not register a
CAN-ID for reception which would be needed for a 1-to-1 ISOTP connection with a
segmented bi-directional data transfer.

Sending SFs on this socket is therefore a TX-only 'broadcast' operation.

Signed-off-by: Oliver Hartkopp 
Signed-off-by: Thomas Wagner 
Link: https://lore.kernel.org/r/20201206144731.4609-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

can: gw: support modification of Classical CAN DLCs

2020-11-20T11:05:14+00:00

Add support for data length code modifications for Classical CAN.

The netlink configuration interface always allowed to pass any value
that fits into a byte, therefore only the modification process had to be
extended to handle the raw DLC represenation of Classical CAN frames.

When a DLC value from 0 .. F is provided for Classical CAN frame
modifications the 'len' value is modified as-is with the exception that
potentially existing 9 .. F DLC values in the len8_dlc element are moved
to the 'len' element for the modification operation by mod_retrieve_ccdlc().

After the modification the Classical CAN frame DLC information is brought
back into the correct format by mod_store_ccdlc() which is filling 'len'
and 'len8_dlc' accordingly.

Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/r/20201119084921.2621-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

can: add optional DLC element to Classical CAN frame structure

2020-11-20T08:43:29+00:00

ISO 11898-1 Chapter 8.4.2.3 defines a 4 bit data length code (DLC) table which
maps the DLC to the payload length of the CAN frame in bytes:

    DLC      ->  payload length
    0 .. 8   ->  0 .. 8
    9 .. 15  ->  8

Although the DLC values 8 .. 15 in Classical CAN always result in a payload
length of 8 bytes these DLC values are transparently transmitted on the CAN
bus. As the struct can_frame only provides a 'len' element (formerly 'can_dlc')
which contains the plain payload length ( 0 .. 8 ) of the CAN frame, the raw
DLC is not visible to the application programmer, e.g. for testing use-cases.

To access the raw DLC values 9 .. 15 the len8_dlc element is introduced, which
is only valid when the payload length 'len' is 8 and the DLC is greater than 8.

The len8_dlc element is filled by the CAN interface driver and used for CAN
frame creation by the CAN driver when the CAN_CTRLMODE_CC_LEN8_DLC flag is
supported by the driver and enabled via netlink configuration interface.

Reported-by: Vincent Mailhol 
Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/r/20201110101852.1973-2-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

can: isotp: implement cleanups / improvements from review

2020-10-12T08:06:08+00:00

As pointed out by Jakub Kicinski here:
http://lore.kernel.org/r/20201009175751.5c54097f@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com
this patch addresses the remarked issues:

- remove empty line in comment
- remove default=y for CAN_ISOTP in Kconfig
- make use of pr_notice_once()
- use GFP_ATOMIC instead of gfp_any() in soft hrtimer context

The version strings in the CAN subsystem are removed by a separate patch.

Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/r/20201012074354.25839-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde