freebsd/share/man/man4/patm.4

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.\" Author: Hartmut Brandt <harti@FreeBSD.org>
.\"
.\" $FreeBSD$
.\"
.\" patm(4) man page
.\"
.Dd July 15, 2003
.Dt PATM 4
.Os
.Sh NAME
.Nm patm
.Nd "device driver for IDT77252 based ATM interfaces (ProSum and IDT)"
.Sh SYNOPSIS
.Cd device patm
.Cd device utopia
.Cd device atm
.Pp
.Cd options NATM
.Cd options LIBMBPOOL
.Sh DESCRIPTION
The
.Nm
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
.Xr natm 4
framework,
.Xr netgraph 4
and HARP.
It provides only PVC services.
Signalling, ATMARP, ILMI and other
higher layer protocols are implemented using
.Xr netgraph 4
or HARP.
.Pp
For configuring the card for IP see
.Xr natmip 4 .
.Pp
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 allowed range) that are not
claimed by other open connections.
This may be used for monitoring purposes.
.Pp
The following sysctls are recognized by the driver additionally to those
handled by
.Xr utopia 4 :
.Bl -tag -width indent
.It Va hw.atm.patm Ns Ar N Ns Va .istats
Returns a list of
.Vt uint32_t
statistic counters with internal driver statistics.
.It Va hw.atm.patm Ns Ar N Ns Va .eeprom
This is a read-only variable containing the contents of the on-board EEPROM
device.
.It Va hw.atm.patm Ns Ar N Ns Va .lbuf_max
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
.Xr loader 8
tunable.
.It Va hw.atm.patm Ns Ar N Ns Va .tx_maxmaps
This is the upper limit of transmission DMA maps the driver will allocate.
This is read-only but may be set via a
.Xr loader 8
tunable.
.It Va hw.atm.patm Ns Ar N Ns Va .debug
.Bf Em
(Only if debugging enabled.)
.Ef
These are debugging flags.
See
.Pa src/sys/dev/patm/if_patmvar.h
for the possible flags.
This may be initialized via a
.Xr loader 8
tunable.
.It Va hw.atm.patm Ns Ar N Ns Va .regs
.Bf Em
(Only if debugging enabled.)
.Ef
Returns the current values of the card's registers.
.It Va hw.atm.patm Ns Ar N Ns Va .tsq
Returns the transmit status queue.
.El
.Pp
When loaded, the driver initializes several variables from
.Xr loader 8
tunables:
.Bl -tag -width indent
.It Va hw.patm Ns Ar N Ns Va .lbuf_max
This initializes the corresponding
.Xr sysctl 8
variable and defines an upper
limit on the number of large receive buffers (mbuf clusters).
.It Va hw.patm Ns Ar N Ns Va .tx_maxmaps
This initializes the corresponding
.Xr sysctl 8
variable and is the maximum
number of DMA maps for transmission that the driver will allocated.
.It Va hw.patm Ns Ar N Ns Va .debug
.Bf Em
(Only if debugging enabled.)
.Ef
Initializes the debugging flags.
.El
.Pp
The driver supports the media options
.Cm sdh , noscramb
and
.Cm unassigned
(see
.Xr 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.
.Sh DIAGNOSTICS
.Bd -literal
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
.Ed
.Sh SEE ALSO
.Xr natm 4 ,
.Xr natmip 4 ,
.Xr utopia 4
.Sh CAVEATS
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.
.Pp
Although the card supports AAL3/4 the driver does not.
.Pp
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 aggressive 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
.Pa /usr/src/sys/dev/patm/genrtab ,
and regenerating them.
.Pp
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.
.Pp
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, according to the documentation, this should not influence cell spacing,
it does, so the driver lets the chip generate idle cells.
.Sh ACKNOWLEDGEMENTS
Thanks to Christian Bucari from ProSum for lending two of these cards to enable
the development of this driver.
Thanks also for answering my questions.
.Sh AUTHORS
.An Harti Brandt Aq harti@FreeBSD.org