Merge tag 'linux-can-fixes-for-5.10-20201103' of...

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

%YAML 1.2

---

$id: http://devicetree.org/schemas/net/can/can-controller.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title: CAN Controller Generic Binding

maintainers:

  - Marc Kleine-Budde <mkl@pengutronix.de>

properties:

  $nodename:

    pattern: "^can(@.*)?$"

additionalProperties: true

...

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

%YAML 1.2

---

$id: http://devicetree.org/schemas/net/can/fsl,flexcan.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title:

  Flexcan CAN controller on Freescale's ARM and PowerPC system-on-a-chip (SOC).

maintainers:

  - Marc Kleine-Budde <mkl@pengutronix.de>

allOf:

  - $ref: can-controller.yaml#

properties:

  compatible:

    oneOf:

      - enum:

          - fsl,imx8qm-flexcan

          - fsl,imx8mp-flexcan

          - fsl,imx6q-flexcan

          - fsl,imx53-flexcan

          - fsl,imx35-flexcan

          - fsl,imx28-flexcan

          - fsl,imx25-flexcan

          - fsl,p1010-flexcan

          - fsl,vf610-flexcan

          - fsl,ls1021ar2-flexcan

          - fsl,lx2160ar1-flexcan

      - items:

          - enum:

              - fsl,imx7d-flexcan

              - fsl,imx6ul-flexcan

              - fsl,imx6sx-flexcan

          - const: fsl,imx6q-flexcan

      - items:

          - enum:

              - fsl,ls1028ar1-flexcan

          - const: fsl,lx2160ar1-flexcan

  reg:

    maxItems: 1

  interrupts:

    maxItems: 1

  clocks:

    maxItems: 2

  clock-names:

    items:

      - const: ipg

      - const: per

  clock-frequency:

    description: |

      The oscillator frequency driving the flexcan device, filled in by the

      boot loader. This property should only be used the used operating system

      doesn't support the clocks and clock-names property.

  xceiver-supply:

    description: Regulator that powers the CAN transceiver.

  big-endian:

    $ref: /schemas/types.yaml#/definitions/flag

    description: |

      This means the registers of FlexCAN controller are big endian. This is

      optional property.i.e. if this property is not present in device tree

      node then controller is assumed to be little endian. If this property is

      present then controller is assumed to be big endian.

  fsl,stop-mode:

    description: |

      Register bits of stop mode control.

      The format should be as follows:

      <gpr req_gpr req_bit>

      gpr is the phandle to general purpose register node.

      req_gpr is the gpr register offset of CAN stop request.

      req_bit is the bit offset of CAN stop request.

    $ref: /schemas/types.yaml#/definitions/phandle-array

    items:

      - description: The 'gpr' is the phandle to general purpose register node.

      - description: The 'req_gpr' is the gpr register offset of CAN stop request.

        maximum: 0xff

      - description: The 'req_bit' is the bit offset of CAN stop request.

        maximum: 0x1f

  fsl,clk-source:

    description: |

      Select the clock source to the CAN Protocol Engine (PE). It's SoC

      implementation dependent. Refer to RM for detailed definition. If this

      property is not set in device tree node then driver selects clock source 1

      by default.

      0: clock source 0 (oscillator clock)

      1: clock source 1 (peripheral clock)

    $ref: /schemas/types.yaml#/definitions/uint32

    default: 1

    minimum: 0

    maximum: 1

  wakeup-source:

    $ref: /schemas/types.yaml#/definitions/flag

    description:

      Enable CAN remote wakeup.

required:

  - compatible

  - reg

  - interrupts

additionalProperties: false

examples:

  - |

    can@1c000 {

        compatible = "fsl,p1010-flexcan";

        reg = <0x1c000 0x1000>;

        interrupts = <48 0x2>;

        interrupt-parent = <&mpic>;

        clock-frequency = <200000000>;

        fsl,clk-source = <0>;

    };

  - |

    #include <dt-bindings/interrupt-controller/irq.h>

    can@2090000 {

        compatible = "fsl,imx6q-flexcan";

        reg = <0x02090000 0x4000>;

        interrupts = <0 110 IRQ_TYPE_LEVEL_HIGH>;

        clocks = <&clks 1>, <&clks 2>;

        clock-names = "ipg", "per";

        fsl,stop-mode = <&gpr 0x34 28>;

    };

Flexcan CAN controller on Freescale's ARM and PowerPC system-on-a-chip (SOC).

Required properties:

- compatible : Should be "fsl,<processor>-flexcan"

  where <processor> is imx8qm, imx6q, imx28, imx53, imx35, imx25, p1010,

  vf610, ls1021ar2, lx2160ar1, ls1028ar1.

  The ls1028ar1 must be followed by lx2160ar1, e.g.

   - "fsl,ls1028ar1-flexcan", "fsl,lx2160ar1-flexcan"

  An implementation should also claim any of the following compatibles

  that it is fully backwards compatible with:

  - fsl,p1010-flexcan

- reg : Offset and length of the register set for this device

- interrupts : Interrupt tuple for this device

Optional properties:

- clock-frequency : The oscillator frequency driving the flexcan device

- xceiver-supply: Regulator that powers the CAN transceiver

- big-endian: This means the registers of FlexCAN controller are big endian.

              This is optional property.i.e. if this property is not present in

              device tree node then controller is assumed to be little endian.

              if this property is present then controller is assumed to be big

              endian.

- fsl,stop-mode: register bits of stop mode control, the format is

		 <&gpr req_gpr req_bit>.

		 gpr is the phandle to general purpose register node.

		 req_gpr is the gpr register offset of CAN stop request.

		 req_bit is the bit offset of CAN stop request.

- fsl,clk-source: Select the clock source to the CAN Protocol Engine (PE).

		  It's SoC Implementation dependent. Refer to RM for detailed

		  definition. If this property is not set in device tree node

		  then driver selects clock source 1 by default.

		  0: clock source 0 (oscillator clock)

		  1: clock source 1 (peripheral clock)

- wakeup-source: enable CAN remote wakeup

Example:

	can@1c000 {

		compatible = "fsl,p1010-flexcan";

		reg = <0x1c000 0x1000>;

		interrupts = <48 0x2>;

		interrupt-parent = <&mpic>;

		clock-frequency = <200000000>; // filled in by bootloader

		fsl,clk-source = <0>; // select clock source 0 for PE

	};

SAE J1939 defines a higher layer protocol on CAN. It implements a more

sophisticated addressing scheme and extends the maximum packet size above 8

bytes. Several derived specifications exist, which differ from the original

J1939 on the application level, like MilCAN A, NMEA2000 and especially

J1939 on the application level, like MilCAN A, NMEA2000, and especially

ISO-11783 (ISOBUS). This last one specifies the so-called ETP (Extended

Transport Protocol) which is has been included in this implementation. This

Transport Protocol), which has been included in this implementation. This

results in a maximum packet size of ((2 ^ 24) - 1) * 7 bytes == 111 MiB.

Specifications used

addressing and transport methods used by J1939.

* **Addressing:** when a process on an ECU communicates via J1939, it should

  not necessarily know its source address. Although at least one process per

  not necessarily know its source address. Although, at least one process per

  ECU should know the source address. Other processes should be able to reuse

  that address. This way, address parameters for different processes

  cooperating for the same ECU, are not duplicated. This way of working is

  closely related to the UNIX concept where programs do just one thing, and do

  closely related to the UNIX concept, where programs do just one thing and do

  it well.

* **Dynamic addressing:** Address Claiming in J1939 is time critical.

  Furthermore data transport should be handled properly during the address

  Furthermore, data transport should be handled properly during the address

  negotiation. Putting this functionality in the kernel eliminates it as a

  requirement for _every_ user space process that communicates via J1939. This

  results in a consistent J1939 bus with proper addressing.

The J1939 sockets operate on CAN network devices (see SocketCAN). Any J1939

user space library operating on CAN raw sockets will still operate properly.

Since such library does not communicate with the in-kernel implementation, care

Since such a library does not communicate with the in-kernel implementation, care

must be taken that these two do not interfere. In practice, this means they

cannot share ECU addresses. A single ECU (or virtual ECU) address is used by

the library exclusively, or by the in-kernel system exclusively.

8 bits : PS (PDU Specific)

In J1939-21 distinction is made between PDU1 format (where PF < 240) and PDU2

format (where PF >= 240). Furthermore, when using PDU2 format, the PS-field

format (where PF >= 240). Furthermore, when using the PDU2 format, the PS-field

contains a so-called Group Extension, which is part of the PGN. When using PDU2

format, the Group Extension is set in the PS-field.

On the other hand, when using PDU1 format, the PS-field contains a so-called

Destination Address, which is _not_ part of the PGN. When communicating a PGN

from user space to kernel (or visa versa) and PDU2 format is used, the PS-field

from user space to kernel (or vice versa) and PDU2 format is used, the PS-field

of the PGN shall be set to zero. The Destination Address shall be set

elsewhere.

Both static and dynamic addressing methods can be used.

For static addresses, no extra checks are made by the kernel, and provided

For static addresses, no extra checks are made by the kernel and provided

addresses are considered right. This responsibility is for the OEM or system

integrator.

For dynamic addressing, so-called Address Claiming, extra support is foreseen

in the kernel. In J1939 any ECU is known by it's 64-bit NAME. At the moment of

in the kernel. In J1939 any ECU is known by its 64-bit NAME. At the moment of

a successful address claim, the kernel keeps track of both NAME and source

address being claimed. This serves as a base for filter schemes. By default,

packets with a destination that is not locally, will be rejected.

packets with a destination that is not locally will be rejected.

Mixed mode packets (from a static to a dynamic address or vice versa) are

allowed. The BSD sockets define separate API calls for getting/setting the

---------

On CAN, you first need to open a socket for communicating over a CAN network.

To use J1939, #include <linux/can/j1939.h>. From there, <linux/can.h> will be

To use J1939, ``#include <linux/can/j1939.h>``. From there, ``<linux/can.h>`` will be

included too. To open a socket, use:

.. code-block:: C

    s = socket(PF_CAN, SOCK_DGRAM, CAN_J1939);

J1939 does use SOCK_DGRAM sockets. In the J1939 specification, connections are

J1939 does use ``SOCK_DGRAM`` sockets. In the J1939 specification, connections are

mentioned in the context of transport protocol sessions. These still deliver

packets to the other end (using several CAN packets). SOCK_STREAM is not

packets to the other end (using several CAN packets). ``SOCK_STREAM`` is not

supported.

After the successful creation of the socket, you would normally use the bind(2)

and/or connect(2) system call to bind the socket to a CAN interface.  After

binding and/or connecting the socket, you can read(2) and write(2) from/to the

socket or use send(2), sendto(2), sendmsg(2) and the recv*() counterpart

After the successful creation of the socket, you would normally use the ``bind(2)``

and/or ``connect(2)`` system call to bind the socket to a CAN interface. After

binding and/or connecting the socket, you can ``read(2)`` and ``write(2)`` from/to the

socket or use ``send(2)``, ``sendto(2)``, ``sendmsg(2)`` and the ``recv*()`` counterpart

operations on the socket as usual. There are also J1939 specific socket options

described below.

In order to send data, a bind(2) must have been successful. bind(2) assigns a

In order to send data, a ``bind(2)`` must have been successful. ``bind(2)`` assigns a

local address to a socket.

Different from CAN is that the payload data is just the data that get send,

without it's header info. The header info is derived from the sockaddr supplied

to bind(2), connect(2), sendto(2) and recvfrom(2). A write(2) with size 4 will

Different from CAN is that the payload data is just the data that get sends,

without its header info. The header info is derived from the sockaddr supplied

to ``bind(2)``, ``connect(2)``, ``sendto(2)`` and ``recvfrom(2)``. A ``write(2)`` with size 4 will

result in a packet with 4 bytes.

The sockaddr structure has extensions for use with J1939 as specified below:

         } can_addr;

      }

can_family & can_ifindex serve the same purpose as for other SocketCAN sockets.

``can_family`` & ``can_ifindex`` serve the same purpose as for other SocketCAN sockets.

can_addr.j1939.pgn specifies the PGN (max 0x3ffff). Individual bits are

``can_addr.j1939.pgn`` specifies the PGN (max 0x3ffff). Individual bits are

specified above.

can_addr.j1939.name contains the 64-bit J1939 NAME.

``can_addr.j1939.name`` contains the 64-bit J1939 NAME.

can_addr.j1939.addr contains the address.

``can_addr.j1939.addr`` contains the address.

The bind(2) system call assigns the local address, i.e. the source address when

sending packages. If a PGN during bind(2) is set, it's used as a RX filter.

The ``bind(2)`` system call assigns the local address, i.e. the source address when

sending packages. If a PGN during ``bind(2)`` is set, it's used as a RX filter.

I.e. only packets with a matching PGN are received. If an ADDR or NAME is set

it is used as a receive filter, too. It will match the destination NAME or ADDR

of the incoming packet. The NAME filter will work only if appropriate Address

Claiming for this name was done on the CAN bus and registered/cached by the

kernel.

On the other hand connect(2) assigns the remote address, i.e. the destination

address. The PGN from connect(2) is used as the default PGN when sending

On the other hand ``connect(2)`` assigns the remote address, i.e. the destination

address. The PGN from ``connect(2)`` is used as the default PGN when sending

packets. If ADDR or NAME is set it will be used as the default destination ADDR

or NAME. Further a set ADDR or NAME during connect(2) is used as a receive

or NAME. Further a set ADDR or NAME during ``connect(2)`` is used as a receive

filter. It will match the source NAME or ADDR of the incoming packet.

Both write(2) and send(2) will send a packet with local address from bind(2) and

the remote address from connect(2). Use sendto(2) to overwrite the destination

Both ``write(2)`` and ``send(2)`` will send a packet with local address from ``bind(2)`` and the

remote address from ``connect(2)``. Use ``sendto(2)`` to overwrite the destination

address.

If can_addr.j1939.name is set (!= 0) the NAME is looked up by the kernel and

the corresponding ADDR is used. If can_addr.j1939.name is not set (== 0),

can_addr.j1939.addr is used.

If ``can_addr.j1939.name`` is set (!= 0) the NAME is looked up by the kernel and

the corresponding ADDR is used. If ``can_addr.j1939.name`` is not set (== 0),

``can_addr.j1939.addr`` is used.

When creating a socket, reasonable defaults are set. Some options can be

modified with setsockopt(2) & getsockopt(2).

modified with ``setsockopt(2)`` & ``getsockopt(2)``.

RX path related options:

- SO_J1939_FILTER - configure array of filters

- SO_J1939_PROMISC - disable filters set by bind(2) and connect(2)

- ``SO_J1939_FILTER`` - configure array of filters

- ``SO_J1939_PROMISC`` - disable filters set by ``bind(2)`` and ``connect(2)``

By default no broadcast packets can be send or received. To enable sending or

receiving broadcast packets use the socket option SO_BROADCAST:

receiving broadcast packets use the socket option ``SO_BROADCAST``:

.. code-block:: C

     +---------------------------+

TX path related options:

SO_J1939_SEND_PRIO - change default send priority for the socket

``SO_J1939_SEND_PRIO`` - change default send priority for the socket

Message Flags during send() and Related System Calls

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

send(2), sendto(2) and sendmsg(2) take a 'flags' argument. Currently

``send(2)``, ``sendto(2)`` and ``sendmsg(2)`` take a 'flags' argument. Currently

supported flags are:

* MSG_DONTWAIT, i.e. non-blocking operation.

* ``MSG_DONTWAIT``, i.e. non-blocking operation.

recvmsg(2)

^^^^^^^^^^

In most cases recvmsg(2) is needed if you want to extract more information than

recvfrom(2) can provide. For example package priority and timestamp. The

In most cases ``recvmsg(2)`` is needed if you want to extract more information than

``recvfrom(2)`` can provide. For example package priority and timestamp. The

Destination Address, name and packet priority (if applicable) are attached to

the msghdr in the recvmsg(2) call. They can be extracted using cmsg(3) macros,

with cmsg_level == SOL_J1939 && cmsg_type == SCM_J1939_DEST_ADDR,

SCM_J1939_DEST_NAME or SCM_J1939_PRIO. The returned data is a uint8_t for

priority and dst_addr, and uint64_t for dst_name.

the msghdr in the ``recvmsg(2)`` call. They can be extracted using ``cmsg(3)`` macros,

with ``cmsg_level == SOL_J1939 && cmsg_type == SCM_J1939_DEST_ADDR``,

``SCM_J1939_DEST_NAME`` or ``SCM_J1939_PRIO``. The returned data is a ``uint8_t`` for

``priority`` and ``dst_addr``, and ``uint64_t`` for ``dst_name``.

.. code-block:: C

Distinction has to be made between using the claimed address and doing an

address claim. To use an already claimed address, one has to fill in the

j1939.name member and provide it to bind(2). If the name had claimed an address

``j1939.name`` member and provide it to ``bind(2)``. If the name had claimed an address

earlier, all further messages being sent will use that address. And the

j1939.addr member will be ignored.

``j1939.addr`` member will be ignored.

An exception on this is PGN 0x0ee00. This is the "Address Claim/Cannot Claim

Address" message and the kernel will use the j1939.addr member for that PGN if

Address" message and the kernel will use the ``j1939.addr`` member for that PGN if

necessary.

To claim an address following code example can be used:

If another ECU claims the address, the kernel will mark the NAME-SA expired.

No socket bound to the NAME can send packets (other than address claims). To

claim another address, some socket bound to NAME, must bind(2) again, but with

only j1939.addr changed to the new SA, and must then send a valid address claim

claim another address, some socket bound to NAME, must ``bind(2)`` again, but with

only ``j1939.addr`` changed to the new SA, and must then send a valid address claim

packet. This restarts the state machine in the kernel (and any other

participant on the bus) for this NAME.

can-utils also include the jacd tool, so it can be used as code example or as

``can-utils`` also include the ``j1939acd`` tool, so it can be used as code example or as

default Address Claiming daemon.

Send Examples

	bind(sock, (struct sockaddr *)&baddr, sizeof(baddr));

Now, the socket 'sock' is bound to the SA 0x20. Since no connect(2) was called,

at this point we can use only sendto(2) or sendmsg(2).

Now, the socket 'sock' is bound to the SA 0x20. Since no ``connect(2)`` was called,

at this point we can use only ``sendto(2)`` or ``sendmsg(2)``.

Send:

		.can_family = AF_CAN,

		.can_addr.j1939 = {

			.name = J1939_NO_NAME;

			.pgn = 0x30,

			.addr = 0x12300,

			.addr = 0x30,

			.pgn = 0x12300,

		},

	};

		 */

		struct sk_buff *skb = priv->echo_skb[idx];

		struct canfd_frame *cf = (struct canfd_frame *)skb->data;

		u8 len = cf->len;

		*len_ptr = len;

		/* get the real payload length for netdev statistics */

		if (cf->can_id & CAN_RTR_FLAG)

			*len_ptr = 0;

		else

			*len_ptr = cf->len;

		priv->echo_skb[idx] = NULL;

		return skb;

	if (!skb)

		return 0;

	netif_rx(skb);

	skb_get(skb);

	if (netif_rx(skb) == NET_RX_SUCCESS)

		dev_consume_skb_any(skb);

	else

		dev_kfree_skb_any(skb);

	return len;

}