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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/networking/z8530drv.txt
downloadlinux-stericsson-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+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+Please note that the information in this document may be hopelessly outdated.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
+
+-----------------------------------------------------------------------------
+
+
+ SCC.C - Linux driver for Z8530 based HDLC cards for AX.25
+
+ ********************************************************************
+
+ (c) 1993,2000 by Joerg Reuter DL1BKE <jreuter@yaina.de>
+
+ portions (c) 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