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linux-next/Documentation/networking/de4x5.txt
Linus Torvalds 1da177e4c3 Linux-2.6.12-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!
2005-04-16 15:20:36 -07:00

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Originally, this driver was written for the Digital Equipment
Corporation series of EtherWORKS Ethernet cards:
DE425 TP/COAX EISA
DE434 TP PCI
DE435 TP/COAX/AUI PCI
DE450 TP/COAX/AUI PCI
DE500 10/100 PCI Fasternet
but it will now attempt to support all cards which conform to the
Digital Semiconductor SROM Specification. The driver currently
recognises the following chips:
DC21040 (no SROM)
DC21041[A]
DC21140[A]
DC21142
DC21143
So far the driver is known to work with the following cards:
KINGSTON
Linksys
ZNYX342
SMC8432
SMC9332 (w/new SROM)
ZNYX31[45]
ZNYX346 10/100 4 port (can act as a 10/100 bridge!)
The driver has been tested on a relatively busy network using the DE425,
DE434, DE435 and DE500 cards and benchmarked with 'ttcp': it transferred
16M of data to a DECstation 5000/200 as follows:
TCP UDP
TX RX TX RX
DE425 1030k 997k 1170k 1128k
DE434 1063k 995k 1170k 1125k
DE435 1063k 995k 1170k 1125k
DE500 1063k 998k 1170k 1125k in 10Mb/s mode
All values are typical (in kBytes/sec) from a sample of 4 for each
measurement. Their error is +/-20k on a quiet (private) network and also
depend on what load the CPU has.
=========================================================================
The ability to load this driver as a loadable module has been included
and used extensively during the driver development (to save those long
reboot sequences). Loadable module support under PCI and EISA has been
achieved by letting the driver autoprobe as if it were compiled into the
kernel. Do make sure you're not sharing interrupts with anything that
cannot accommodate interrupt sharing!
To utilise this ability, you have to do 8 things:
0) have a copy of the loadable modules code installed on your system.
1) copy de4x5.c from the /linux/drivers/net directory to your favourite
temporary directory.
2) for fixed autoprobes (not recommended), edit the source code near
line 5594 to reflect the I/O address you're using, or assign these when
loading by:
insmod de4x5 io=0xghh where g = bus number
hh = device number
NB: autoprobing for modules is now supported by default. You may just
use:
insmod de4x5
to load all available boards. For a specific board, still use
the 'io=?' above.
3) compile de4x5.c, but include -DMODULE in the command line to ensure
that the correct bits are compiled (see end of source code).
4) if you are wanting to add a new card, goto 5. Otherwise, recompile a
kernel with the de4x5 configuration turned off and reboot.
5) insmod de4x5 [io=0xghh]
6) run the net startup bits for your new eth?? interface(s) manually
(usually /etc/rc.inet[12] at boot time).
7) enjoy!
To unload a module, turn off the associated interface(s)
'ifconfig eth?? down' then 'rmmod de4x5'.
Automedia detection is included so that in principle you can disconnect
from, e.g. TP, reconnect to BNC and things will still work (after a
pause whilst the driver figures out where its media went). My tests
using ping showed that it appears to work....
By default, the driver will now autodetect any DECchip based card.
Should you have a need to restrict the driver to DIGITAL only cards, you
can compile with a DEC_ONLY define, or if loading as a module, use the
'dec_only=1' parameter.
I've changed the timing routines to use the kernel timer and scheduling
functions so that the hangs and other assorted problems that occurred
while autosensing the media should be gone. A bonus for the DC21040
auto media sense algorithm is that it can now use one that is more in
line with the rest (the DC21040 chip doesn't have a hardware timer).
The downside is the 1 'jiffies' (10ms) resolution.
IEEE 802.3u MII interface code has been added in anticipation that some
products may use it in the future.
The SMC9332 card has a non-compliant SROM which needs fixing - I have
patched this driver to detect it because the SROM format used complies
to a previous DEC-STD format.
I have removed the buffer copies needed for receive on Intels. I cannot
remove them for Alphas since the Tulip hardware only does longword
aligned DMA transfers and the Alphas get alignment traps with non
longword aligned data copies (which makes them really slow). No comment.
I have added SROM decoding routines to make this driver work with any
card that supports the Digital Semiconductor SROM spec. This will help
all cards running the dc2114x series chips in particular. Cards using
the dc2104x chips should run correctly with the basic driver. I'm in
debt to <mjacob@feral.com> for the testing and feedback that helped get
this feature working. So far we have tested KINGSTON, SMC8432, SMC9332
(with the latest SROM complying with the SROM spec V3: their first was
broken), ZNYX342 and LinkSys. ZNYX314 (dual 21041 MAC) and ZNYX 315
(quad 21041 MAC) cards also appear to work despite their incorrectly
wired IRQs.
I have added a temporary fix for interrupt problems when some SCSI cards
share the same interrupt as the DECchip based cards. The problem occurs
because the SCSI card wants to grab the interrupt as a fast interrupt
(runs the service routine with interrupts turned off) vs. this card
which really needs to run the service routine with interrupts turned on.
This driver will now add the interrupt service routine as a fast
interrupt if it is bounced from the slow interrupt. THIS IS NOT A
RECOMMENDED WAY TO RUN THE DRIVER and has been done for a limited time
until people sort out their compatibility issues and the kernel
interrupt service code is fixed. YOU SHOULD SEPARATE OUT THE FAST
INTERRUPT CARDS FROM THE SLOW INTERRUPT CARDS to ensure that they do not
run on the same interrupt. PCMCIA/CardBus is another can of worms...
Finally, I think I have really fixed the module loading problem with
more than one DECchip based card. As a side effect, I don't mess with
the device structure any more which means that if more than 1 card in
2.0.x is installed (4 in 2.1.x), the user will have to edit
linux/drivers/net/Space.c to make room for them. Hence, module loading
is the preferred way to use this driver, since it doesn't have this
limitation.
Where SROM media detection is used and full duplex is specified in the
SROM, the feature is ignored unless lp->params.fdx is set at compile
time OR during a module load (insmod de4x5 args='eth??:fdx' [see
below]). This is because there is no way to automatically detect full
duplex links except through autonegotiation. When I include the
autonegotiation feature in the SROM autoconf code, this detection will
occur automatically for that case.
Command line arguments are now allowed, similar to passing arguments
through LILO. This will allow a per adapter board set up of full duplex
and media. The only lexical constraints are: the board name (dev->name)
appears in the list before its parameters. The list of parameters ends
either at the end of the parameter list or with another board name. The
following parameters are allowed:
fdx for full duplex
autosense to set the media/speed; with the following
sub-parameters:
TP, TP_NW, BNC, AUI, BNC_AUI, 100Mb, 10Mb, AUTO
Case sensitivity is important for the sub-parameters. They *must* be
upper case. Examples:
insmod de4x5 args='eth1:fdx autosense=BNC eth0:autosense=100Mb'.
For a compiled in driver, in linux/drivers/net/CONFIG, place e.g.
DE4X5_OPTS = -DDE4X5_PARM='"eth0:fdx autosense=AUI eth2:autosense=TP"'
Yes, I know full duplex isn't permissible on BNC or AUI; they're just
examples. By default, full duplex is turned off and AUTO is the default
autosense setting. In reality, I expect only the full duplex option to
be used. Note the use of single quotes in the two examples above and the
lack of commas to separate items.