se_hdlc - on-board high-performance serial HDLC interface


     se@bus_address:port_number[, hdlc]


     The se_hdlc devices are a synchronous hdlc-framing interface
     for  the   se  serial  devices.  Both  built-in serial ports
     (port_number)  on platforms which have the  se  serial  dev-
     ices, support synchronous data transfer at a maximum rate of
     384 kbps. bus_address is the platform  specific   se  device
     bus address. port_number is a single digit number (0-9).


     The se_hdlcn devices provide a data path which supports  the
     transfer  of  data via read(2) and write(2) system calls, as
     well as ioctl(2) calls.  Data path opens  are  exclusive  in
     order  to  protect against injection or diversion of data by
     another process.

     The se_hdlc device provides a separate control path for  use
     by  programs  that need to configure or monitor a connection
     independent of any exclusive access restrictions imposed  by
     data path opens.  Up to three control paths may be active on
     a particular serial channel at any one time.   Control  path
     accesses  are  restricted  to  ioctl(2)  calls only; no data
     transfer is possible.

     When used in synchronous modes, the SAB 82532 ESCC  supports
     several  options for clock sourcing and data encolding. Both
     the transmit and receive clock sources can be set to be  the
     external  Transmit  clock  (TRxC),  external  Receive  Clock
     (RTxC), the internal Baud Rate Generator (BRG), or the  out-
     put of the ESCC 's Digital Phase-Lock Loop (DPLL).

     The BRG is a programmable divisor that derives a clock  fre-
     quency  from  the  PCLK  input  signal to the ESCC. The pro-
     grammed baud rate is translated into a floating  point   (6-
     bit  mantissa, 4-bit exponent) number  time constant that is
     stored in the ESCC.

     A local loopback mode is available,  primarily  for  use  by
     syncloop(1M)  for  testing  purposes, and should not be con-
     fused with SDLC loop mode, which is not  supported  on  this
     interface.   Also, an auto-echo feature may be selected that
     causes all incoming data to be routed to the  transmit  data
     line,  allowing the port to act as the remote end of a digi-
     tal loop. Neither of these options should be selected  casu-
     ally, or left in use when not needed.

     The se driver keeps running totals of various hardware  gen-
     erated  events   for each channel.  These include numbers of
     packets and characters sent and received,  abort  conditions
     detected  by  the  receiver,  receive  CRC  errors, transmit
     underruns,  receive  overruns,  input  errors   and   output
     errors,  and message block allocation failures. Input errors
     are logged whenever an incoming message must be   discarded,
     such  as  when  an abort or CRC error is detected, a receive
     overrun occurs, or when no message  block  is  available  to
     store  incoming data. Output errors are logged when the data
     must  be  discarded  due  to  underruns,  CTS  drops  during
     transmission,  CTS  timeouts, or excessive watchdog timeouts
     caused by a cable break.


     The se driver supports the following  ioctl() commands.

           Return  a  struct   scc_mode   containing   parameters
           currently  in  use.  These  include  the  transmit and
           receive clock sources, boolean loopback and  NRZI mode
           flags and the integer baud rate.

           The argument is a struct scc_mode from which the  ESCC
           channel will be programmed.

           Return a struct sl_stats containing the current totals
           of hardware-generated events.
            These include numbers of packets and characters  sent
           and  received  by  the  driver,  aborts and CRC errors
           detected, transmit underruns, and receive overruns.

           Clear the hardware statistics for this channel.

           Returns the currently set baud  rate  as  an  integer.
           This  may not reflect the actual data transfer rate if
           external clocks are used.

           Returns the current state of the CTS and DCD  incoming
           modem interface signals as an integer.

     The following structures are used with se hdlc ioctl()  com-

     struct scc_mode {
      char sm_txclock;    /* transmit clock sources */
      char sm_rxclock;    /* receive clock sources */
      char sm_iflags;     /* data and clock inversion flags (non-zsh) */
      uchar_t sm_config;  /* boolean configuration options */
      int sm_baudrate;    /* real baud rate */
      int sm_retval;      /* reason codes for ioctl failures */
     struct sl_stats {
      long     ipack;        /* input packets */
      long     opack;        /* output packets */
      long     ichar;        /* input bytes */
      long     ochar;        /* output bytes */
      long     abort;        /* abort received */
      long     crc;          /* CRC error */
      long     cts;          /* CTS timeouts */
      long     dcd;          /* Carrier drops */
      long     overrun;      /* receive overrun */
      long     underrun;     /* transmit underrun */
      long     ierror;       /* input error */
      long     oerror;       /* output error */
      long     nobuffers;    /* receive side memory allocation failure */


     An open() will fail if a STREAMS  message  block  cannot  be
     allocated or under the following conditions:

          ENXIO The unit being opened does not exist.

          EBUSY The device is in use by another serial protocol.

     An ioctl() will fail under the following conditions:

                An attempt was made to select an invalid clocking

                The baud rate specified for  use  with  the  baud
                rate  generator  would  translate  to a null time
                constant in the ESCC's registers.


     /dev/se_hdlc[0-1], /dev/se_hdlc
           character-special devices

           header file specifying synchronous  serial  communica-
           tion definitions


     See attributes(5) for descriptions of the  following  attri-

    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    | Architecture                | SPARC                       |


     syncinit(1M), syncloop(1M), syncstat(1M), ioctl(2), open(2),
     read(2), write(2), attributes(5), se(7D), zsh(7D)

     Siemens ESCC2 SAB 82532 Enhanced Serial  Communication  Con-
     troller User's Manual


     se_hdlc clone open failed, no memory, rq=nnn
           A kernel memory  allocation  failed  for  one  of  the
           private  data  structures.  The  value  of  nnn is the
           address of the read queue passed to open(2).

     se_hdlc: clone device must be attached before use!
           An operation was  attempted  through  a  control  path
           before  that  path  had  been attached to a particular
           serial channel.

     se_hdlcn: not initialized, can't send message
           An M_DATA message was passed to the driver for a chan-
           nel  that  had not been programmed at least once since
           the driver was loaded.  The ESCC's registers were   in
           an unknown state.  The S_IOCSETMODE ioctl command per-
           forms the programming operation.

     sen hdlc_start: Invalid message type d on write queue
           driver received an invalid message type from streams.

     se_hdlcn: transmit hung
           The transmitter was not successfully  restarted  after
           the  watchdog timer expired. This is usually caused by
           a bad or disconnected cable.

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