diff options
Diffstat (limited to 'kernel/Documentation/networking/can.txt')
| -rw-r--r-- | kernel/Documentation/networking/can.txt | 106 |
1 files changed, 83 insertions, 23 deletions
diff --git a/kernel/Documentation/networking/can.txt b/kernel/Documentation/networking/can.txt index 5abad1e92..05fd83bb3 100644 --- a/kernel/Documentation/networking/can.txt +++ b/kernel/Documentation/networking/can.txt @@ -268,6 +268,9 @@ solution for a couple of reasons: struct can_frame { canid_t can_id; /* 32 bit CAN_ID + EFF/RTR/ERR flags */ __u8 can_dlc; /* frame payload length in byte (0 .. 8) */ + __u8 __pad; /* padding */ + __u8 __res0; /* reserved / padding */ + __u8 __res1; /* reserved / padding */ __u8 data[8] __attribute__((aligned(8))); }; @@ -507,7 +510,7 @@ 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 + As described in chapter 3.3 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. The possible errors are divided into different error classes that may be filtered @@ -678,7 +681,7 @@ solution for a couple of reasons: addr.can_family = AF_CAN; addr.can_ifindex = ifr.ifr_ifindex; - connect(s, (struct sockaddr *)&addr, sizeof(addr)) + connect(s, (struct sockaddr *)&addr, sizeof(addr)); (..) @@ -1015,25 +1018,34 @@ solution for a couple of reasons: $ ip link set can0 type can help Usage: ip link set DEVICE type can - [ bitrate BITRATE [ sample-point SAMPLE-POINT] ] | - [ tq TQ prop-seg PROP_SEG phase-seg1 PHASE-SEG1 - phase-seg2 PHASE-SEG2 [ sjw SJW ] ] - - [ loopback { on | off } ] - [ listen-only { on | off } ] - [ triple-sampling { on | off } ] - - [ restart-ms TIME-MS ] - [ restart ] - - Where: BITRATE := { 1..1000000 } - SAMPLE-POINT := { 0.000..0.999 } - TQ := { NUMBER } - PROP-SEG := { 1..8 } - PHASE-SEG1 := { 1..8 } - PHASE-SEG2 := { 1..8 } - SJW := { 1..4 } - RESTART-MS := { 0 | NUMBER } + [ bitrate BITRATE [ sample-point SAMPLE-POINT] ] | + [ tq TQ prop-seg PROP_SEG phase-seg1 PHASE-SEG1 + phase-seg2 PHASE-SEG2 [ sjw SJW ] ] + + [ dbitrate BITRATE [ dsample-point SAMPLE-POINT] ] | + [ dtq TQ dprop-seg PROP_SEG dphase-seg1 PHASE-SEG1 + dphase-seg2 PHASE-SEG2 [ dsjw SJW ] ] + + [ loopback { on | off } ] + [ listen-only { on | off } ] + [ triple-sampling { on | off } ] + [ one-shot { on | off } ] + [ berr-reporting { on | off } ] + [ fd { on | off } ] + [ fd-non-iso { on | off } ] + [ presume-ack { on | off } ] + + [ restart-ms TIME-MS ] + [ restart ] + + Where: BITRATE := { 1..1000000 } + SAMPLE-POINT := { 0.000..0.999 } + TQ := { NUMBER } + PROP-SEG := { 1..8 } + PHASE-SEG1 := { 1..8 } + PHASE-SEG2 := { 1..8 } + SJW := { 1..4 } + RESTART-MS := { 0 | NUMBER } - Display CAN device details and statistics: @@ -1149,7 +1161,7 @@ solution for a couple of reasons: $ ip link set canX type can restart Note that a restart will also create a CAN error message frame (see - also chapter 3.4). + also chapter 3.3). 6.6 CAN FD (flexible data rate) driver support @@ -1175,7 +1187,55 @@ solution for a couple of reasons: The CAN device MTU can be retrieved e.g. with a SIOCGIFMTU ioctl() syscall. N.B. CAN FD capable devices can also handle and send legacy CAN frames. - FIXME: Add details about the CAN FD controller configuration when available. + When configuring CAN FD capable CAN controllers an additional 'data' bitrate + has to be set. This bitrate for the data phase of the CAN FD frame has to be + at least the bitrate which was configured for the arbitration phase. This + second bitrate is specified analogue to the first bitrate but the bitrate + setting keywords for the 'data' bitrate start with 'd' e.g. dbitrate, + dsample-point, dsjw or dtq and similar settings. When a data bitrate is set + within the configuration process the controller option "fd on" can be + specified to enable the CAN FD mode in the CAN controller. This controller + option also switches the device MTU to 72 (CANFD_MTU). + + The first CAN FD specification presented as whitepaper at the International + CAN Conference 2012 needed to be improved for data integrity reasons. + Therefore two CAN FD implementations have to be distinguished today: + + - ISO compliant: The ISO 11898-1:2015 CAN FD implementation (default) + - non-ISO compliant: The CAN FD implementation following the 2012 whitepaper + + Finally there are three types of CAN FD controllers: + + 1. ISO compliant (fixed) + 2. non-ISO compliant (fixed, like the M_CAN IP core v3.0.1 in m_can.c) + 3. ISO/non-ISO CAN FD controllers (switchable, like the PEAK PCAN-USB FD) + + The current ISO/non-ISO mode is announced by the CAN controller driver via + netlink and displayed by the 'ip' tool (controller option FD-NON-ISO). + The ISO/non-ISO-mode can be altered by setting 'fd-non-iso {on|off}' for + switchable CAN FD controllers only. + + Example configuring 500 kbit/s arbitration bitrate and 4 Mbit/s data bitrate: + + $ ip link set can0 up type can bitrate 500000 sample-point 0.75 \ + dbitrate 4000000 dsample-point 0.8 fd on + $ ip -details link show can0 + 5: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 72 qdisc pfifo_fast state UNKNOWN \ + mode DEFAULT group default qlen 10 + link/can promiscuity 0 + can <FD> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 + bitrate 500000 sample-point 0.750 + tq 50 prop-seg 14 phase-seg1 15 phase-seg2 10 sjw 1 + pcan_usb_pro_fd: tseg1 1..64 tseg2 1..16 sjw 1..16 brp 1..1024 \ + brp-inc 1 + dbitrate 4000000 dsample-point 0.800 + dtq 12 dprop-seg 7 dphase-seg1 8 dphase-seg2 4 dsjw 1 + pcan_usb_pro_fd: dtseg1 1..16 dtseg2 1..8 dsjw 1..4 dbrp 1..1024 \ + dbrp-inc 1 + clock 80000000 + + Example when 'fd-non-iso on' is added on this switchable CAN FD adapter: + can <FD,FD-NON-ISO> state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 6.7 Supported CAN hardware |