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PATM(4)			 BSD Kernel Interfaces Manual		       PATM(4)

     patm -- device driver for IDT77252	based ATM interfaces (ProSum and IDT)

     device patm
     device utopia
     device atm

     options NATM
     options LIBMBPOOL

     The patm device driver supports ATM cards based on	the IDT77252 chip.  It
     has been tested with ProSum's ProATM-155 cards and	with IDT's evaluation
     boards.  The driver interfaces with the natm(4) framework,	netgraph(4)
     and HARP.	It provides only PVC services.	Signalling, ATMARP, ILMI and
     other higher layer	protocols are implemented using	netgraph(4) or HARP.

     For configuring the card for IP see natmip(4).

     The driver	supports UBR, CBR, VBR and ABR traffic.	 Supported AALs	are:
     AAL0 (cell	payloads), AAL5	and raw	AAL.  The driver supports opening of
     VCI/VPI 0/0 in RX,	raw AAL-mode.  This VC will receive all	incoming cells
     (even those with non-zero GFC fields and VPI/VCI values outside the al-
     lowed range) that are not claimed by other	open connections.  This	may be
     used for monitoring purposes.

     The following sysctls are recognized by the driver	additionally to	those
     handled by	utopia(4):

	     Returns a list of uint32_t	statistic counters with	internal
	     driver statistics.

	     This is a read-only variable containing the contents of the on-
	     board EEPROM device.

	     This puts an upper	limit on the number of large receive buffers
	     the driver	will allocate.	This is	a read-only variable that can
	     be	set via	a loader(8) tunable.

	     This is the upper limit of	transmission DMA maps the driver will
	     allocate.	This is	read-only but may be set via a loader(8) tun-

	     (Only if debugging	enabled.)  These are debugging flags.  See
	     src/sys/dev/patm/if_patmvar.h for the possible flags.  This may
	     be	initialized via	a loader(8) tunable.

	     (Only if debugging	enabled.)  Returns the current values of the
	     card's registers.

	     Returns the transmit status queue.

     When loaded, the driver initializes several variables from	loader(8) tun-

	     This initializes the corresponding	sysctl(8) variable and defines
	     an	upper limit on the number of large receive buffers (mbuf clus-

	     This initializes the corresponding	sysctl(8) variable and is the
	     maximum number of DMA maps	for transmission that the driver will

	     (Only if debugging	enabled.)  Initializes the debugging flags.

     The driver	supports the media options sdh,	noscramb and unassigned	(see
     utopia(4))	when the card is a 155MBit card.  Both PMC-Sierra S/UNI	and
     IDT77155 PHY chips	are supported for these	cards.	For 25MBit cards the
     IDT77105 is supported.

     patm1: <NICStAR (77222/77252) ATM adapter>	port 0xc000-0xc0ff mem 0xf8000000-0xf83fffff,0xf4000000-0xf4000fff irq 11 at device 8.0	on pci2
     patm1: IDT77252 155MBit interface;	idt77252 Rev. G; IDT77155 PHY
     patm1: 128K x 32 SRAM; 4096 connections

     natm(4), natmip(4), utopia(4)

     The card fails to generate	an interrupt if	a cell is received in AAL0
     mode that has the MSB of the PTI field cleared.  Therefore	cells will be
     delivered on the next receive interrupt which can happen either when the
     receive status queue is full, or a	cell with the last bit of the PTI set
     is	received.

     Although the card supports	AAL3/4 the driver does not.

     The rate tables used by this driver are not the tables recommended	by IDT
     (they are wrong anyway).  The driver's tables are slightly	more aggres-
     sive than IDT's.  That means, that	the actual cell	rate can be slightly
     higher than the specified.	 This is in contrast to	the IDT	tables where
     cell rates	5% less	than the allowed one have been observed.  This can be
     changed by	changing the program that generates these tables, found	in
     /usr/src/sys/dev/patm/genrtab, and	regenerating them.

     The reported media	for the	155MBit	cards will always be OC3/MM, because
     there is no (known	to me) way to figure out the actual medium.  The
     medium should really be coded in the EEPROM by the	manufacturer.

     The Tx cell counter in the	utopia statistics is wrong, because the	chip
     uses idle cells for spacing and the PHY counts these cells.  While	there
     is	a configuration	option for the chip to switch of these cells and, ac-
     cording to	the documentation, this	should not influence cell spacing, it
     does, so the driver lets the chip generate	idle cells.

     Thanks to Christian Bucari	from ProSum for	lending	two of these cards to
     enable the	development of this driver.  Thanks also for answering my

     Harti Brandt <>

BSD				 July 15, 2003				   BSD


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