Commit d6e640f9 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

can: update documentation wording error frames -> error messages 



As Heinz-Juergen Oertel pointed out 'CAN error frames' are a already defined
term for the CAN protocol violation indication on the wire.

To avoid confusion with the error messages created by CAN drivers available
via CAN RAW sockets update the documentation and change the naming from
'error frames' to 'error messages' or 'error message frames'.

Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 8b5e218d

Documentation/networking/can.txt

+16 −16
Original line number Diff line number Diff line
@@ -232,16 +232,16 @@ solution for a couple of reasons: 
  arbitration problems and error frames caused by the different

  ECUs. The occurrence of detected errors are important for diagnosis

  and have to be logged together with the exact timestamp. For this

  reason the CAN interface driver can generate so called Error Frames

  that can optionally be passed to the user application in the same

  way as other CAN frames. Whenever an error on the physical layer

  reason the CAN interface driver can generate so called Error Message

  Frames that can optionally be passed to the user application in the

  same way as other CAN frames. Whenever an error on the physical layer

  or the MAC layer is detected (e.g. by the CAN controller) the driver

  creates an appropriate error frame. Error frames can be requested by

  the user application using the common CAN filter mechanisms. Inside

  this filter definition the (interested) type of errors may be

  selected. The reception of error frames is disabled by default.

  The format of the CAN error frame is briefly described in the Linux

  header file "include/linux/can/error.h".

  creates an appropriate error message frame. Error messages frames can

  be requested by the user application using the common CAN filter

  mechanisms. Inside this filter definition the (interested) type of

  errors may be selected. The reception of error messages is disabled

  by default. The format of the CAN error message frame is briefly

  described in the Linux header file "include/linux/can/error.h".



4. How to use Socket CAN

------------------------
@@ -383,7 +383,7 @@ solution for a couple of reasons: 
  defaults are set at RAW socket binding time:



  - The filters are set to exactly one filter receiving everything

  - The socket only receives valid data frames (=> no error frames)

  - The socket only receives valid data frames (=> no error message frames)

  - The loopback of sent CAN frames is enabled (see chapter 3.2)

  - The socket does not receive its own sent frames (in loopback mode)
@@ -434,7 +434,7 @@ solution for a couple of reasons: 
  4.1.2 RAW socket option CAN_RAW_ERR_FILTER



  As described in chapter 3.4 the CAN interface driver can generate so

  called Error Frames that can optionally be passed to the user

  called Error Message Frames that can optionally be passed to the user

  application in the same way as other CAN frames. The possible

  errors are divided into different error classes that may be filtered

  using the appropriate error mask. To register for every possible
@@ -527,7 +527,7 @@ solution for a couple of reasons: 


    rcvlist_all - list for unfiltered entries (no filter operations)

    rcvlist_eff - list for single extended frame (EFF) entries

    rcvlist_err - list for error frames masks

    rcvlist_err - list for error message frames masks

    rcvlist_fil - list for mask/value filters

    rcvlist_inv - list for mask/value filters (inverse semantic)

    rcvlist_sff - list for single standard frame (SFF) entries
@@ -784,13 +784,13 @@ solution for a couple of reasons: 
    $ ip link set canX type can restart-ms 100



  Alternatively, the application may realize the "bus-off" condition

  by monitoring CAN error frames and do a restart when appropriate with

  the command:

  by monitoring CAN error message frames and do a restart when

  appropriate with the command:



    $ ip link set canX type can restart



  Note that a restart will also create a CAN error frame (see also

  chapter 3.4).

  Note that a restart will also create a CAN error message frame (see

  also chapter 3.4).



  6.6 Supported CAN hardware

include/linux/can.h

+4 −4
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ 
/* special address description flags for the CAN_ID */

#define CAN_EFF_FLAG 0x80000000U /* EFF/SFF is set in the MSB */

#define CAN_RTR_FLAG 0x40000000U /* remote transmission request */

#define CAN_ERR_FLAG 0x20000000U /* error frame */

#define CAN_ERR_FLAG 0x20000000U /* error message frame */



/* valid bits in CAN ID for frame formats */

#define CAN_SFF_MASK 0x000007FFU /* standard frame format (SFF) */
@@ -32,14 +32,14 @@ 
 * Controller Area Network Identifier structure

 *

 * bit 0-28	: CAN identifier (11/29 bit)

 * bit 29	: error frame flag (0 = data frame, 1 = error frame)

 * bit 29	: error message frame flag (0 = data frame, 1 = error message)

 * bit 30	: remote transmission request flag (1 = rtr frame)

 * bit 31	: frame format flag (0 = standard 11 bit, 1 = extended 29 bit)

 */

typedef __u32 canid_t;



/*

 * Controller Area Network Error Frame Mask structure

 * Controller Area Network Error Message Frame Mask structure

 *

 * bit 0-28	: error class mask (see include/linux/can/error.h)

 * bit 29-31	: set to zero
@@ -97,7 +97,7 @@ struct sockaddr_can { 
 *          <received_can_id> & mask == can_id & mask

 *

 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can

 * filter for error frames (CAN_ERR_FLAG bit set in mask).

 * filter for error message frames (CAN_ERR_FLAG bit set in mask).

 */

struct can_filter {

	canid_t can_id;

include/linux/can/error.h

+2 −2
Original line number Diff line number Diff line 
/*

 * linux/can/error.h

 *

 * Definitions of the CAN error frame to be filtered and passed to the user.

 * Definitions of the CAN error messages to be filtered and passed to the user.

 *

 * Author: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>

 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
@@ -12,7 +12,7 @@ 
#ifndef CAN_ERROR_H

#define CAN_ERROR_H



#define CAN_ERR_DLC 8 /* dlc for error frames */

#define CAN_ERR_DLC 8 /* dlc for error message frames */



/* error class (mask) in can_id */

#define CAN_ERR_TX_TIMEOUT   0x00000001U /* TX timeout (by netdevice driver) */

net/can/af_can.c

+5 −5
Original line number Diff line number Diff line
@@ -334,8 +334,8 @@ static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) 
 *  relevant bits for the filter.

 *

 *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can

 *  filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames

 *  there is a special filterlist and a special rx path filter handling.

 *  filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg

 *  frames there is a special filterlist and a special rx path filter handling.

 *

 * Return:

 *  Pointer to optimal filterlist for the given can_id/mask pair.
@@ -347,7 +347,7 @@ static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 
{

	canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */



	/* filter for error frames in extra filterlist */

	/* filter for error message frames in extra filterlist */

	if (*mask & CAN_ERR_FLAG) {

		/* clear CAN_ERR_FLAG in filter entry */

		*mask &= CAN_ERR_MASK;
@@ -408,7 +408,7 @@ static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 
 *          <received_can_id> & mask == can_id & mask

 *

 *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can

 *  filter for error frames (CAN_ERR_FLAG bit set in mask).

 *  filter for error message frames (CAN_ERR_FLAG bit set in mask).

 *

 *  The provided pointer to the sk_buff is guaranteed to be valid as long as

 *  the callback function is running. The callback function must *not* free
@@ -578,7 +578,7 @@ static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 
		return 0;



	if (can_id & CAN_ERR_FLAG) {

		/* check for error frame entries only */

		/* check for error message frame entries only */

		hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {

			if (can_id & r->mask) {

				deliver(skb, r);

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