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1.. SPDX-License-Identifier: GPL-2.02 3==================4Generic HDLC layer5==================6 7Krzysztof Halasa <khc@pm.waw.pl>8 9 10Generic HDLC layer currently supports:11 121. Frame Relay (ANSI, CCITT, Cisco and no LMI)13 14 - Normal (routed) and Ethernet-bridged (Ethernet device emulation)15 interfaces can share a single PVC.16 - ARP support (no InARP support in the kernel - there is an17 experimental InARP user-space daemon available on:18 http://www.kernel.org/pub/linux/utils/net/hdlc/).19 202. raw HDLC - either IP (IPv4) interface or Ethernet device emulation213. Cisco HDLC224. PPP235. X.25 (uses X.25 routines).24 25Generic HDLC is a protocol driver only - it needs a low-level driver26for your particular hardware.27 28Ethernet device emulation (using HDLC or Frame-Relay PVC) is compatible29with IEEE 802.1Q (VLANs) and 802.1D (Ethernet bridging).30 31 32Make sure the hdlc.o and the hardware driver are loaded. It should33create a number of "hdlc" (hdlc0 etc) network devices, one for each34WAN port. You'll need the "sethdlc" utility, get it from:35 36 http://www.kernel.org/pub/linux/utils/net/hdlc/37 38Compile sethdlc.c utility::39 40 gcc -O2 -Wall -o sethdlc sethdlc.c41 42Make sure you're using a correct version of sethdlc for your kernel.43 44Use sethdlc to set physical interface, clock rate, HDLC mode used,45and add any required PVCs if using Frame Relay.46Usually you want something like::47 48 sethdlc hdlc0 clock int rate 12800049 sethdlc hdlc0 cisco interval 10 timeout 2550 51or::52 53 sethdlc hdlc0 rs232 clock ext54 sethdlc hdlc0 fr lmi ansi55 sethdlc hdlc0 create 9956 ifconfig hdlc0 up57 ifconfig pvc0 localIP pointopoint remoteIP58 59In Frame Relay mode, ifconfig master hdlc device up (without assigning60any IP address to it) before using pvc devices.61 62 63Setting interface:64 65* v35 | rs232 | x21 | t1 | e166 - sets physical interface for a given port67 if the card has software-selectable interfaces68 loopback69 - activate hardware loopback (for testing only)70* clock ext71 - both RX clock and TX clock external72* clock int73 - both RX clock and TX clock internal74* clock txint75 - RX clock external, TX clock internal76* clock txfromrx77 - RX clock external, TX clock derived from RX clock78* rate79 - sets clock rate in bps (for "int" or "txint" clock only)80 81 82Setting protocol:83 84* hdlc - sets raw HDLC (IP-only) mode85 86 nrz / nrzi / fm-mark / fm-space / manchester - sets transmission code87 88 no-parity / crc16 / crc16-pr0 (CRC16 with preset zeros) / crc32-itu89 90 crc16-itu (CRC16 with ITU-T polynomial) / crc16-itu-pr0 - sets parity91 92* hdlc-eth - Ethernet device emulation using HDLC. Parity and encoding93 as above.94 95* cisco - sets Cisco HDLC mode (IP, IPv6 and IPX supported)96 97 interval - time in seconds between keepalive packets98 99 timeout - time in seconds after last received keepalive packet before100 we assume the link is down101 102* ppp - sets synchronous PPP mode103 104* x25 - sets X.25 mode105 106* fr - Frame Relay mode107 108 lmi ansi / ccitt / cisco / none - LMI (link management) type109 110 dce - Frame Relay DCE (network) side LMI instead of default DTE (user).111 112 It has nothing to do with clocks!113 114 - t391 - link integrity verification polling timer (in seconds) - user115 - t392 - polling verification timer (in seconds) - network116 - n391 - full status polling counter - user117 - n392 - error threshold - both user and network118 - n393 - monitored events count - both user and network119 120Frame-Relay only:121 122* create n | delete n - adds / deletes PVC interface with DLCI #n.123 Newly created interface will be named pvc0, pvc1 etc.124 125* create ether n | delete ether n - adds a device for Ethernet-bridged126 frames. The device will be named pvceth0, pvceth1 etc.127 128 129 130 131Board-specific issues132---------------------133 134n2.o and c101.o need parameters to work::135 136 insmod n2 hw=io,irq,ram,ports[:io,irq,...]137 138example::139 140 insmod n2 hw=0x300,10,0xD0000,01141 142or::143 144 insmod c101 hw=irq,ram[:irq,...]145 146example::147 148 insmod c101 hw=9,0xdc000149 150If built into the kernel, these drivers need kernel (command line) parameters::151 152 n2.hw=io,irq,ram,ports:...153 154or::155 156 c101.hw=irq,ram:...157 158 159 160If you have a problem with N2, C101 or PLX200SYN card, you can issue the161"private" command to see port's packet descriptor rings (in kernel logs)::162 163 sethdlc hdlc0 private164 165The hardware driver has to be build with #define DEBUG_RINGS.166Attaching this info to bug reports would be helpful. Anyway, let me know167if you have problems using this.168 169For patches and other info look at:170<http://www.kernel.org/pub/linux/utils/net/hdlc/>.171