Date: Wed, 17 Mar 1999 22:10:14 +0100 From: Gerald Heinig <heinig@hdz-ima.rwth-aachen.de> To: freebsd-isdn@freebsd.org, hm@hcs.de Subject: I/O base address for ISAC/HSCX Message-ID: <36F01A36.8EB476A8@hdz-ima.rwth-aachen.de>
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Hi,
I've finally found the time again to have a look at the i4b internals
and I have a question which has been bugging me for a while now: why do
you do all that I/O address translation ie. base + offset -
somethingelse in the Fritz card low-level driver? more specifically,
the lines
#define AVM_CONF_REG 0x1800 /* base offset for config register */
#define AVM_CONF_IRQ 0x1801 /* base offset for IRQ register */
/* config register write */
in i4b_avm_a1.c are a source of puzzlement. Where do you get the 0x1800
from? Aren't the first set of ISAC registers simply mapped consecutively
at I/O address (one of: 0x200/0x240/0x300/0x340)? If they're mapped
elsewhere, where did this info come from? [hmm.. let me guess... AVM?
:-) ].
Another bit is where you do the following: i4b_avm_a1.c line 121
insb((int)base - 0x3e0, (u_char *)buf, (u_int)len);
^^^^^^^^^^^^^
Why the base +/- offset business?
Cheers,
Gerald
--
"Would you like to buy an encyclopaedia to help your child get to
college?"
"He doesn't need it. He takes the bus!"
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