magma man page on OpenBSD

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MAGMA(4)	     OpenBSD Programmer's Manual (SPARC64)	      MAGMA(4)

     magma - Magma Sp Serial/Parallel board device driver

     magma? at sbus?
     mtty? at magma?
     mbpp? at magma?

     This driver provides an interface to Magma LC2+1Sp, 2+1Sp, 4+1Sp, 8+2Sp,
     4Sp, 8Sp, 12Sp, 16Sp, 1P, 2P, and 2+1HS boards.  These boards are based
     around the Cirrus Logic CD1400 serial/parallel communications engine and
     the Cirrus Logic CD1190 parallel communications engine.

     The device minor numbers for this driver are encoded as follows:

	 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
	   |   |   |   |   |   |   |   |
	   |   |   |   |   +---+---+---+---> port number
	   |   |   |   |
	   |   |   |   +-------------------> dial-out (on tty ports)
	   |   |   |
	   |   |   +-----------------------> unused
	   |   |
	   +---+---------------------------> card number

     Up to four cards are supported in the system.

     All tty ports have full automatic hardware (RTS/CTS) flow control
     available and a 12 byte FIFO on the chip in each direction so errors
     should be minimal.

     /dev/tty[mno][0-f]	 Serial ports
     /dev/bpp[mno][0-1]	 Parallel ports

     mtty%d%x: ring buffer overflow  Incoming characters have been discarded
     due to a buffer overflow.	This is caused by the process in control of
     the device not reading characters fast enough.  If need be you can make
     the ring buffer bigger by changing the MAGMA_RBUF_SIZE #define to
     something bigger, but it should be a multiple of two.

     mtty%d%x: fifo overflow  Incoming characters have been discarded due to a
     CD1400 channel overrun.  This is caused by interrupts not being serviced
     sufficiently quickly to prevent the 12 byte receive FIFO on a serial
     channel from overflowing.	Reducing the value of either the
     MTTY_RX_FIFO_THRESHOLD or MTTY_RX_DTR_THRESHOLD #define's to something
     smaller may help slow machines avoid this problem.

     intro(4), sbus(4), tty(4)

     The driver was loosely based upon the cy(4) Cyclades Cyclom device driver
     written by Andrew Herbert and Timo Rossi.

     The driver was written by Iain Hibbert <>

     CD1190 parallel support.

     bpp input.

     Dial-out (cua) devices are not yet supported.

     mdmbuf is unsupported.

     Automatic XON/XOFF handshaking could be implemented fairly easily.

     It would be good if the tty port waited for the FIFO to empty before
     allowing a close, so that I could turn off the channel interrupts at that
     time.  It can be done.

OpenBSD 4.9		       November 29, 2008		   OpenBSD 4.9

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