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diff --git a/Documentation/networking/z8530drv.rst b/Documentation/networking/z8530drv.rst new file mode 100644 index 000000000000..d2942760f167 --- /dev/null +++ b/Documentation/networking/z8530drv.rst @@ -0,0 +1,686 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +========================================================= +SCC.C - Linux driver for Z8530 based HDLC cards for AX.25 +========================================================= + + +This is a subset of the documentation. To use this driver you MUST have the +full package from: + +Internet: + + 1. ftp://ftp.ccac.rwth-aachen.de/pub/jr/z8530drv-utils_3.0-3.tar.gz + + 2. ftp://ftp.pspt.fi/pub/ham/linux/ax25/z8530drv-utils_3.0-3.tar.gz + +Please note that the information in this document may be hopelessly outdated. +A new version of the documentation, along with links to other important +Linux Kernel AX.25 documentation and programs, is available on +http://yaina.de/jreuter + +Copyright |copy| 1993,2000 by Joerg Reuter DL1BKE <jreuter@yaina.de> + +portions Copyright |copy| 1993 Guido ten Dolle PE1NNZ + +for the complete copyright notice see >> Copying.Z8530DRV << + +1. Initialization of the driver +=============================== + +To use the driver, 3 steps must be performed: + + 1. if compiled as module: loading the module + 2. Setup of hardware, MODEM and KISS parameters with sccinit + 3. Attach each channel to the Linux kernel AX.25 with "ifconfig" + +Unlike the versions below 2.4 this driver is a real network device +driver. If you want to run xNOS instead of our fine kernel AX.25 +use a 2.x version (available from above sites) or read the +AX.25-HOWTO on how to emulate a KISS TNC on network device drivers. + + +1.1 Loading the module +====================== + +(If you're going to compile the driver as a part of the kernel image, + skip this chapter and continue with 1.2) + +Before you can use a module, you'll have to load it with:: + + insmod scc.o + +please read 'man insmod' that comes with module-init-tools. + +You should include the insmod in one of the /etc/rc.d/rc.* files, +and don't forget to insert a call of sccinit after that. It +will read your /etc/z8530drv.conf. + +1.2. /etc/z8530drv.conf +======================= + +To setup all parameters you must run /sbin/sccinit from one +of your rc.*-files. This has to be done BEFORE you can +"ifconfig" an interface. Sccinit reads the file /etc/z8530drv.conf +and sets the hardware, MODEM and KISS parameters. A sample file is +delivered with this package. Change it to your needs. + +The file itself consists of two main sections. + +1.2.1 configuration of hardware parameters +========================================== + +The hardware setup section defines the following parameters for each +Z8530:: + + chip 1 + data_a 0x300 # data port A + ctrl_a 0x304 # control port A + data_b 0x301 # data port B + ctrl_b 0x305 # control port B + irq 5 # IRQ No. 5 + pclock 4915200 # clock + board BAYCOM # hardware type + escc no # enhanced SCC chip? (8580/85180/85280) + vector 0 # latch for interrupt vector + special no # address of special function register + option 0 # option to set via sfr + + +chip + - this is just a delimiter to make sccinit a bit simpler to + program. A parameter has no effect. + +data_a + - the address of the data port A of this Z8530 (needed) +ctrl_a + - the address of the control port A (needed) +data_b + - the address of the data port B (needed) +ctrl_b + - the address of the control port B (needed) + +irq + - the used IRQ for this chip. Different chips can use different + IRQs or the same. If they share an interrupt, it needs to be + specified within one chip-definition only. + +pclock - the clock at the PCLK pin of the Z8530 (option, 4915200 is + default), measured in Hertz + +board + - the "type" of the board: + + ======================= ======== + SCC type value + ======================= ======== + PA0HZP SCC card PA0HZP + EAGLE card EAGLE + PC100 card PC100 + PRIMUS-PC (DG9BL) card PRIMUS + BayCom (U)SCC card BAYCOM + ======================= ======== + +escc + - if you want support for ESCC chips (8580, 85180, 85280), set + this to "yes" (option, defaults to "no") + +vector + - address of the vector latch (aka "intack port") for PA0HZP + cards. There can be only one vector latch for all chips! + (option, defaults to 0) + +special + - address of the special function register on several cards. + (option, defaults to 0) + +option - The value you write into that register (option, default is 0) + +You can specify up to four chips (8 channels). If this is not enough, +just change:: + + #define MAXSCC 4 + +to a higher value. + +Example for the BAYCOM USCC: +---------------------------- + +:: + + chip 1 + data_a 0x300 # data port A + ctrl_a 0x304 # control port A + data_b 0x301 # data port B + ctrl_b 0x305 # control port B + irq 5 # IRQ No. 5 (#) + board BAYCOM # hardware type (*) + # + # SCC chip 2 + # + chip 2 + data_a 0x302 + ctrl_a 0x306 + data_b 0x303 + ctrl_b 0x307 + board BAYCOM + +An example for a PA0HZP card: +----------------------------- + +:: + + chip 1 + data_a 0x153 + data_b 0x151 + ctrl_a 0x152 + ctrl_b 0x150 + irq 9 + pclock 4915200 + board PA0HZP + vector 0x168 + escc no + # + # + # + chip 2 + data_a 0x157 + data_b 0x155 + ctrl_a 0x156 + ctrl_b 0x154 + irq 9 + pclock 4915200 + board PA0HZP + vector 0x168 + escc no + +A DRSI would should probably work with this: +-------------------------------------------- +(actually: two DRSI cards...) + +:: + + chip 1 + data_a 0x303 + data_b 0x301 + ctrl_a 0x302 + ctrl_b 0x300 + irq 7 + pclock 4915200 + board DRSI + escc no + # + # + # + chip 2 + data_a 0x313 + data_b 0x311 + ctrl_a 0x312 + ctrl_b 0x310 + irq 7 + pclock 4915200 + board DRSI + escc no + +Note that you cannot use the on-board baudrate generator off DRSI +cards. Use "mode dpll" for clock source (see below). + +This is based on information provided by Mike Bilow (and verified +by Paul Helay) + +The utility "gencfg" +-------------------- + +If you only know the parameters for the PE1CHL driver for DOS, +run gencfg. It will generate the correct port addresses (I hope). +Its parameters are exactly the same as the ones you use with +the "attach scc" command in net, except that the string "init" must +not appear. Example:: + + gencfg 2 0x150 4 2 0 1 0x168 9 4915200 + +will print a skeleton z8530drv.conf for the OptoSCC to stdout. + +:: + + gencfg 2 0x300 2 4 5 -4 0 7 4915200 0x10 + +does the same for the BAYCOM USCC card. In my opinion it is much easier +to edit scc_config.h... + + +1.2.2 channel configuration +=========================== + +The channel definition is divided into three sub sections for each +channel: + +An example for scc0:: + + # DEVICE + + device scc0 # the device for the following params + + # MODEM / BUFFERS + + speed 1200 # the default baudrate + clock dpll # clock source: + # dpll = normal half duplex operation + # external = MODEM provides own Rx/Tx clock + # divider = use full duplex divider if + # installed (1) + mode nrzi # HDLC encoding mode + # nrzi = 1k2 MODEM, G3RUH 9k6 MODEM + # nrz = DF9IC 9k6 MODEM + # + bufsize 384 # size of buffers. Note that this must include + # the AX.25 header, not only the data field! + # (optional, defaults to 384) + + # KISS (Layer 1) + + txdelay 36 # (see chapter 1.4) + persist 64 + slot 8 + tail 8 + fulldup 0 + wait 12 + min 3 + maxkey 7 + idle 3 + maxdef 120 + group 0 + txoff off + softdcd on + slip off + +The order WITHIN these sections is unimportant. The order OF these +sections IS important. The MODEM parameters are set with the first +recognized KISS parameter... + +Please note that you can initialize the board only once after boot +(or insmod). You can change all parameters but "mode" and "clock" +later with the Sccparam program or through KISS. Just to avoid +security holes... + +(1) this divider is usually mounted on the SCC-PBC (PA0HZP) or not + present at all (BayCom). It feeds back the output of the DPLL + (digital pll) as transmit clock. Using this mode without a divider + installed will normally result in keying the transceiver until + maxkey expires --- of course without sending anything (useful). + +2. Attachment of a channel by your AX.25 software +================================================= + +2.1 Kernel AX.25 +================ + +To set up an AX.25 device you can simply type:: + + ifconfig scc0 44.128.1.1 hw ax25 dl0tha-7 + +This will create a network interface with the IP number 44.128.20.107 +and the callsign "dl0tha". If you do not have any IP number (yet) you +can use any of the 44.128.0.0 network. Note that you do not need +axattach. The purpose of axattach (like slattach) is to create a KISS +network device linked to a TTY. Please read the documentation of the +ax25-utils and the AX.25-HOWTO to learn how to set the parameters of +the kernel AX.25. + +2.2 NOS, NET and TFKISS +======================= + +Since the TTY driver (aka KISS TNC emulation) is gone you need +to emulate the old behaviour. The cost of using these programs is +that you probably need to compile the kernel AX.25, regardless of whether +you actually use it or not. First setup your /etc/ax25/axports, +for example:: + + 9k6 dl0tha-9 9600 255 4 9600 baud port (scc3) + axlink dl0tha-15 38400 255 4 Link to NOS + +Now "ifconfig" the scc device:: + + ifconfig scc3 44.128.1.1 hw ax25 dl0tha-9 + +You can now axattach a pseudo-TTY:: + + axattach /dev/ptys0 axlink + +and start your NOS and attach /dev/ptys0 there. The problem is that +NOS is reachable only via digipeating through the kernel AX.25 +(disastrous on a DAMA controlled channel). To solve this problem, +configure "rxecho" to echo the incoming frames from "9k6" to "axlink" +and outgoing frames from "axlink" to "9k6" and start:: + + rxecho + +Or simply use "kissbridge" coming with z8530drv-utils:: + + ifconfig scc3 hw ax25 dl0tha-9 + kissbridge scc3 /dev/ptys0 + + +3. Adjustment and Display of parameters +======================================= + +3.1 Displaying SCC Parameters: +============================== + +Once a SCC channel has been attached, the parameter settings and +some statistic information can be shown using the param program:: + + dl1bke-u:~$ sccstat scc0 + + Parameters: + + speed : 1200 baud + txdelay : 36 + persist : 255 + slottime : 0 + txtail : 8 + fulldup : 1 + waittime : 12 + mintime : 3 sec + maxkeyup : 7 sec + idletime : 3 sec + maxdefer : 120 sec + group : 0x00 + txoff : off + softdcd : on + SLIP : off + + Status: + + HDLC Z8530 Interrupts Buffers + ----------------------------------------------------------------------- + Sent : 273 RxOver : 0 RxInts : 125074 Size : 384 + Received : 1095 TxUnder: 0 TxInts : 4684 NoSpace : 0 + RxErrors : 1591 ExInts : 11776 + TxErrors : 0 SpInts : 1503 + Tx State : idle + + +The status info shown is: + +============== ============================================================== +Sent number of frames transmitted +Received number of frames received +RxErrors number of receive errors (CRC, ABORT) +TxErrors number of discarded Tx frames (due to various reasons) +Tx State status of the Tx interrupt handler: idle/busy/active/tail (2) +RxOver number of receiver overruns +TxUnder number of transmitter underruns +RxInts number of receiver interrupts +TxInts number of transmitter interrupts +EpInts number of receiver special condition interrupts +SpInts number of external/status interrupts +Size maximum size of an AX.25 frame (*with* AX.25 headers!) +NoSpace number of times a buffer could not get allocated +============== ============================================================== + +An overrun is abnormal. If lots of these occur, the product of +baudrate and number of interfaces is too high for the processing +power of your computer. NoSpace errors are unlikely to be caused by the +driver or the kernel AX.25. + + +3.2 Setting Parameters +====================== + + +The setting of parameters of the emulated KISS TNC is done in the +same way in the SCC driver. You can change parameters by using +the kissparms program from the ax25-utils package or use the program +"sccparam":: + + sccparam <device> <paramname> <decimal-|hexadecimal value> + +You can change the following parameters: + +=========== ===== +param value +=========== ===== +speed 1200 +txdelay 36 +persist 255 +slottime 0 +txtail 8 +fulldup 1 +waittime 12 +mintime 3 +maxkeyup 7 +idletime 3 +maxdefer 120 +group 0x00 +txoff off +softdcd on +SLIP off +=========== ===== + + +The parameters have the following meaning: + +speed: + The baudrate on this channel in bits/sec + + Example: sccparam /dev/scc3 speed 9600 + +txdelay: + The delay (in units of 10 ms) after keying of the + transmitter, until the first byte is sent. This is usually + called "TXDELAY" in a TNC. When 0 is specified, the driver + will just wait until the CTS signal is asserted. This + assumes the presence of a timer or other circuitry in the + MODEM and/or transmitter, that asserts CTS when the + transmitter is ready for data. + A normal value of this parameter is 30-36. + + Example: sccparam /dev/scc0 txd 20 + +persist: + This is the probability that the transmitter will be keyed + when the channel is found to be free. It is a value from 0 + to 255, and the probability is (value+1)/256. The value + should be somewhere near 50-60, and should be lowered when + the channel is used more heavily. + + Example: sccparam /dev/scc2 persist 20 + +slottime: + This is the time between samples of the channel. It is + expressed in units of 10 ms. About 200-300 ms (value 20-30) + seems to be a good value. + + Example: sccparam /dev/scc0 slot 20 + +tail: + The time the transmitter will remain keyed after the last + byte of a packet has been transferred to the SCC. This is + necessary because the CRC and a flag still have to leave the + SCC before the transmitter is keyed down. The value depends + on the baudrate selected. A few character times should be + sufficient, e.g. 40ms at 1200 baud. (value 4) + The value of this parameter is in 10 ms units. + + Example: sccparam /dev/scc2 4 + +full: + The full-duplex mode switch. This can be one of the following + values: + + 0: The interface will operate in CSMA mode (the normal + half-duplex packet radio operation) + 1: Fullduplex mode, i.e. the transmitter will be keyed at + any time, without checking the received carrier. It + will be unkeyed when there are no packets to be sent. + 2: Like 1, but the transmitter will remain keyed, also + when there are no packets to be sent. Flags will be + sent in that case, until a timeout (parameter 10) + occurs. + + Example: sccparam /dev/scc0 fulldup off + +wait: + The initial waittime before any transmit attempt, after the + frame has been queue for transmit. This is the length of + the first slot in CSMA mode. In full duplex modes it is + set to 0 for maximum performance. + The value of this parameter is in 10 ms units. + + Example: sccparam /dev/scc1 wait 4 + +maxkey: + The maximal time the transmitter will be keyed to send + packets, in seconds. This can be useful on busy CSMA + channels, to avoid "getting a bad reputation" when you are + generating a lot of traffic. After the specified time has + elapsed, no new frame will be started. Instead, the trans- + mitter will be switched off for a specified time (parameter + min), and then the selected algorithm for keyup will be + started again. + The value 0 as well as "off" will disable this feature, + and allow infinite transmission time. + + Example: sccparam /dev/scc0 maxk 20 + +min: + This is the time the transmitter will be switched off when + the maximum transmission time is exceeded. + + Example: sccparam /dev/scc3 min 10 + +idle: + This parameter specifies the maximum idle time in full duplex + 2 mode, in seconds. When no frames have been sent for this + time, the transmitter will be keyed down. A value of 0 is + has same result as the fullduplex mode 1. This parameter + can be disabled. + + Example: sccparam /dev/scc2 idle off # transmit forever + +maxdefer + This is the maximum time (in seconds) to wait for a free channel + to send. When this timer expires the transmitter will be keyed + IMMEDIATELY. If you love to get trouble with other users you + should set this to a very low value ;-) + + Example: sccparam /dev/scc0 maxdefer 240 # 2 minutes + + +txoff: + When this parameter has the value 0, the transmission of packets + is enable. Otherwise it is disabled. + + Example: sccparam /dev/scc2 txoff on + +group: + It is possible to build special radio equipment to use more than + one frequency on the same band, e.g. using several receivers and + only one transmitter that can be switched between frequencies. + Also, you can connect several radios that are active on the same + band. In these cases, it is not possible, or not a good idea, to + transmit on more than one frequency. The SCC driver provides a + method to lock transmitters on different interfaces, using the + "param <interface> group <x>" command. This will only work when + you are using CSMA mode (parameter full = 0). + + The number <x> must be 0 if you want no group restrictions, and + can be computed as follows to create restricted groups: + <x> is the sum of some OCTAL numbers: + + + === ======================================================= + 200 This transmitter will only be keyed when all other + transmitters in the group are off. + 100 This transmitter will only be keyed when the carrier + detect of all other interfaces in the group is off. + 0xx A byte that can be used to define different groups. + Interfaces are in the same group, when the logical AND + between their xx values is nonzero. + === ======================================================= + + Examples: + + When 2 interfaces use group 201, their transmitters will never be + keyed at the same time. + + When 2 interfaces use group 101, the transmitters will only key + when both channels are clear at the same time. When group 301, + the transmitters will not be keyed at the same time. + + Don't forget to convert the octal numbers into decimal before + you set the parameter. + + Example: (to be written) + +softdcd: + use a software dcd instead of the real one... Useful for a very + slow squelch. + + Example: sccparam /dev/scc0 soft on + + +4. Problems +=========== + +If you have tx-problems with your BayCom USCC card please check +the manufacturer of the 8530. SGS chips have a slightly +different timing. Try Zilog... A solution is to write to register 8 +instead to the data port, but this won't work with the ESCC chips. +*SIGH!* + +A very common problem is that the PTT locks until the maxkeyup timer +expires, although interrupts and clock source are correct. In most +cases compiling the driver with CONFIG_SCC_DELAY (set with +make config) solves the problems. For more hints read the (pseudo) FAQ +and the documentation coming with z8530drv-utils. + +I got reports that the driver has problems on some 386-based systems. +(i.e. Amstrad) Those systems have a bogus AT bus timing which will +lead to delayed answers on interrupts. You can recognize these +problems by looking at the output of Sccstat for the suspected +port. If it shows under- and overruns you own such a system. + +Delayed processing of received data: This depends on + +- the kernel version + +- kernel profiling compiled or not + +- a high interrupt load + +- a high load of the machine --- running X, Xmorph, XV and Povray, + while compiling the kernel... hmm ... even with 32 MB RAM ... ;-) + Or running a named for the whole .ampr.org domain on an 8 MB + box... + +- using information from rxecho or kissbridge. + +Kernel panics: please read /linux/README and find out if it +really occurred within the scc driver. + +If you cannot solve a problem, send me + +- a description of the problem, +- information on your hardware (computer system, scc board, modem) +- your kernel version +- the output of cat /proc/net/z8530 + +4. Thor RLC100 +============== + +Mysteriously this board seems not to work with the driver. Anyone +got it up-and-running? + + +Many thanks to Linus Torvalds and Alan Cox for including the driver +in the Linux standard distribution and their support. + +:: + + Joerg Reuter ampr-net: dl1bke@db0pra.ampr.org + AX-25 : DL1BKE @ DB0ABH.#BAY.DEU.EU + Internet: jreuter@yaina.de + WWW : http://yaina.de/jreuter |