initial checkin from subversion
This commit is contained in:
Tretter
486
par.c
Normal file
486
par.c
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@@ -0,0 +1,486 @@
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/*
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* par.c V0.32
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*
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* Copyright (C) by R.E.Wolff -- R.E.Wolff@BitWizard.nl
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*
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* This software may be used and distributed according to the terms
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* of the GNU Public License, incorporated herein by reference.
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*
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* I prefer if you try to contact me if you have enhancements,
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* instead of forking off a different branch.....
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*
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* date by what
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* Written: Apr 8 1996 REW initial revision
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* changed: Apr 11 1996 REW Added some more comments.
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* changed: May 12 1996 REW Finished the "read" code.
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* changed: May 15 1996 REW Fixed detection. Code cleanup.
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* changed: May 16 1996 PK Removed depreciated put_fs_byte call
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* Fixed the BIT(x) macro
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* The wake-up woke up the wrong process
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* Added and removed some debugging code
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* Init_module now initializes rstate
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* Locked out forbidden bits
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* Inverted inverting inputs and outputs
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* Made D0..D7 readable (renumbered others)
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* changed: May 18 1996 REW Incorporated above changes with cleanup.
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* fixed crash at rmmod time.
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* changed: May 23 1996 PK Added locking for outputs
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*
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* who-is-who:
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* initials full name Email address
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* REW Roger E. Wolff R.E.Wolff@BitWizard.nl
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* PK Peter Knoppers knop@duteca.et.tudelft.nl
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*
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* This kernel module can be used instead of lp or plip.
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* It will give you access to the bits on the parallel port.
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*
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* You can control external devices this way. As an example, here
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* is the schematic for a set of 8 leds:
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*
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* name pinno
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* / _____
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* D0 2 -----|>|---|_____|-------+
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* / _____ |
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* D1 3 -----|>|---|_____|-------+
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* / _____ |
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* D2 4 -----|>|---|_____|-------+
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* / _____ |
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* D3 5 -----|>|---|_____|-------+
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* / _____ |
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* D4 6 -----|>|---|_____|-------+
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* / _____ |
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* D5 7 -----|>|---|_____|-------+
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* / _____ |
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* D6 8 -----|>|---|_____|-------+
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* / _____ |
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* D7 9 -----|>|---|_____|-------+
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* |
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* GND 25 -------------------------+
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*
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* /
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* You can use any led ( -|>|- ) you can find. The resistors need
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* to be in the 200 to 1k region. 200 ohms will make them quite bright.
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* (14 ma current), I have them much weaker (3.5 ma current).
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* For testing on my laptop, I currently use 810 ohms..... A modern
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* datasheet mentions 14 ma as the source drive capability.
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*
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* Original Paralel ports are spec-ed to 2 ma at 2.4 volts. The IEEE1284
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* spec states 14ma. This is good enough for a led :-)
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*
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**************************************************************************
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*
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* For reference: the pinout of the par port:
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* data relative
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* pin pin direction minor
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* number name in/out number
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* 1 STROBE out ?
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* 2 D0 out 0
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* 3 D1 out 1
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* 4 D2 out 2
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* 5 D3 out 3
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* 6 D4 out 4
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* 7 D5 out 5
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* 8 D6 out 6
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* 9 D7 out 7
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* 10 ACK in
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* 11 BUSY in
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* 12 PAPOUT in
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* 13 SLCT in
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* 14 AUTOFD out ?
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* 15 ERROR in
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* 16 INIT out ?
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* 17 SLCTIN out ?
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* 18-25 GND
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*
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**************************************************************************
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*
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* The devices in /dev are:
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*
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* par0a - par0h (minors 0-7 ) -> D0-D7 on lp0,
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* par0i - par0l (minors 8-11) -> control outputs on lp0
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* par1a - par1h (minors 16-23) -> D0-D7 on lp1,
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* par1i - par1l (minors 24-27) -> control outputs on lp1
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* par2a - par2h (minors 32-39) -> D0-D7 on lp2,
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* par2i - par2l (minors 40-43) -> control outputs on lp2
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*
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* Most modern computers only have lp1.
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*
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* use
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* mknod parXY c 60 <minor>
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* where 60 is the (current) major number....
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*
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* insmod with "base=0xYYY" if you have a port at a weird address.
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* (-- untested: tell me if it works... :-)
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*
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* - Inputs.
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* A par port has about 5 inputs. They can be polled at say
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* 50 ms intervals without too much overhead. (My 386sx25 has
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* been doing that about 200 million times in 4 months)
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* the driver will implement blocking-read (no polling in userspace!).
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* DONE.
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**************************************************************************
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*
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* BUGS and restrictions:
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*
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* (bug me about it if you want it fixed/enhanced -- that's why
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* they are called bugs..... :-)
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*
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* -More than 5 inputs.
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* IF (notice the big if....) your port is 8255 compatible
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* without any buffering between the port and the chip, it
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* should be possible to reconfigure the chip to give about 13
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* inputs available on the connector.
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*
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*
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* -A major number should be allocated with the devices coordinator.
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* -- Under way....
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*
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* -Like lp.c and plip.c this doesn't allocate the region at open-time
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* but when the device is initialized. This means that you can't compile
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* two of these into the kernel. If I'm going to reconfigure the 8255,
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* it might not even be a bad idea to keep it this way.....
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*
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* -Cannot be compiled into the kernel. Only module.
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*
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* -driver interpreted scripts. Allows low-overhead and accurate
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* timing to be done....
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*/
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#include <linux/module.h>
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/delay.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/ioport.h>
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#include <asm/bitops.h>
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#include <asm/io.h>
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#include <asm/segment.h>
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/* Debugging stuff. */
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#ifdef EBUG
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#define DEBUG
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#endif
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#ifdef DEBUG
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#define dprintk(a) printk a
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#else
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#define dprintk(f)
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#endif
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/* Administratrivia */
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#ifndef PAR_MAJOR
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#define PAR_MAJOR 60
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#endif
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/* Hardware related stuff */
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#define NR_BITS_PER_PORT 16 /* best if this is a power of two */
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#define ALLOWEDWRITEBITS 0x0fff /* three bits reserved, one bit enables IRQ */
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#define INVERTEDOUTPUTS 0x0b00 /* three bits are inverted in the hardware */
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#define ALLOWEDREADBITS 0xf8ff /* two bits reserved, one bit is IRQ status */
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#define INVERTEDINPUTBITS 0x8000 /* one bit is inverted in the hardware */
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#define POLL_INTERVAL 5
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#define NR_PAR 3
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int base[NR_PAR]={0x3bc,0x378,0x278};
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int exists[NR_PAR]={0,};
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#if NR_BITS_PER_PORT != 16
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#warning "There are several places where NR_BITS_PER_PORT is fixed at 16"
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#warning "Just changing the define doesn't work."
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#endif
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/* Local variables. */
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static unsigned short state[NR_PAR]={0,};
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static int nreaders = 0;
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static struct timer_list par_timer;
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struct switch_info {
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struct wait_queue *waitq;
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int bitval;
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int nreaders;
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int nwriters;
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};
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struct switch_info pdat[NR_PAR*NR_BITS_PER_PORT];
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#define BIT(x) ((rstate[(x) / NR_BITS_PER_PORT] >> ((x) % NR_BITS_PER_PORT)) & 1)
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static unsigned short rstate[NR_PAR];
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static unsigned short orstate[NR_PAR];
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static unsigned long lastread;
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#define DATAPORT(i) (base[i]+0)
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#define STATUSPORT(i) (base[i]+1)
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#define CTRLPORT(i) (base[i]+2)
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static void update_rstate (void)
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{
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int i;
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for (i=0;i<NR_PAR;i++)
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if (exists[i]) {
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rstate[i] = (((inb (DATAPORT(i)) & 0xff) ) |
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((inb (STATUSPORT(i)) * 0xff) << 8)) ^
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INVERTEDINPUTBITS;
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}
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lastread = jiffies;
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}
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static int par_write(struct inode * inode,
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struct file * file,
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const char * buf,
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int count)
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{
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unsigned int minor = MINOR(inode->i_rdev);
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int port,bit;
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port = minor / NR_BITS_PER_PORT;
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bit = minor % NR_BITS_PER_PORT;
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buf += count-1;
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if (get_user (buf) & 1)
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set_bit (minor,state);
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else
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clear_bit (minor,state);
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dprintk (("setting port %d (0x%3x) to %02x.\n",
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port,DATAPORT(port),state[port]));
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if (bit % NR_BITS_PER_PORT < 8)
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outb ((state[port] ^ INVERTEDOUTPUTS) , DATAPORT(port));
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else
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outb ((state[port] ^ INVERTEDOUTPUTS) >> 8, CTRLPORT(port));
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return count;
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}
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/*
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* Bug: if you are not guaranteed to see all transitions.
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*
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* Bug: If two processes wait for the same input pin, only
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* One will correctly work (maybe alternating). This needs fixing.
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*/
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static int par_read(struct inode * inode, struct file * file,
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char * buf, int count)
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{
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int bitno = MINOR(inode->i_rdev);
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int t;
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struct switch_info *pd = pdat+bitno;
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dprintk(("par_read: request for minor %d, current value = %d\n", bitno,
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pd->bitval));
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while (pd->bitval == (t = BIT(bitno))) {
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interruptible_sleep_on(& pd->waitq);
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if (current->signal & ~current->blocked)
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return -ERESTARTSYS;
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}
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pd->bitval = t;
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put_user (t,buf++);
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return 1;
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}
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/* XXX Is this correct? */
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static int par_select(struct inode * inode, struct file * file,
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int sel_type, select_table * wait)
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{
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int bitno = MINOR(inode->i_rdev);
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int bitval;
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/* Check sel_type? */
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bitval = pdat[bitno].bitval;
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if (bitval != BIT (bitno)) return 1;
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select_wait( & pdat[bitno].waitq, wait);
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return 0;
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}
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static void par_timer_function (unsigned long data)
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{
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int i,j;
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unsigned short t;
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if (lastread != jiffies) update_rstate ();
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for (i=0;i<NR_PAR;i++) {
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if ((t = orstate[i] ^ rstate[i])) {
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for (j=i*NR_BITS_PER_PORT;t != 0;t >>= 1,j++) {
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if ((t & 1) && (pdat[j].nreaders)) {
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wake_up(&pdat[j].waitq);
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}
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}
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orstate[i] = rstate[i];
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}
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}
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par_timer.expires = jiffies + POLL_INTERVAL;
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add_timer (&par_timer);
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}
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static int par_open(struct inode * inode, struct file * file)
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{
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int minor = MINOR(inode->i_rdev);
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dprintk (("par_open called. Minor = %d.\n", minor));
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if (file->f_flags == O_RDWR) {
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printk ("par: Cannot do both read and write on minor %d.\n",minor);
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return -EPERM;
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}
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if (!exists [minor / NR_BITS_PER_PORT])
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return -ENODEV;
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if (file->f_flags == O_RDONLY) {
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if ((1 << (minor % NR_BITS_PER_PORT) & ALLOWEDREADBITS) == 0)
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return -ENODEV;
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pdat[minor].bitval = -1;
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pdat[minor].nreaders++;
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dprintk(("par_open: nreaders for minor %d is now %d\n", minor,
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pdat[minor].nreaders));
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if (!nreaders) {
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init_timer (&par_timer);
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par_timer.function = par_timer_function;
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par_timer.expires = jiffies+POLL_INTERVAL;
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add_timer (&par_timer);
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dprintk(("par_open: timer added, at jiffies=%ld, expires at %ld\n",
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jiffies, par_timer.expires));
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dprintk(("par_open: rstate=[%02x,%02x,%02x]\n",
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rstate[0], rstate[1], rstate[2]));
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}
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nreaders++;
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} else {
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if ((1 << (minor % NR_BITS_PER_PORT) & ALLOWEDWRITEBITS) == 0)
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return -ENODEV;
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if (pdat[minor].nwriters)
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return -EBUSY;
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pdat[minor].nwriters++;
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}
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MOD_INC_USE_COUNT;
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return 0;
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}
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static void par_release(struct inode * inode, struct file * file)
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{
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if (file->f_flags == O_RDONLY) {
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nreaders--;
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if (!nreaders) {
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del_timer (&par_timer);
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}
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} else
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pdat[MINOR(inode->i_rdev)].nwriters--;
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MOD_DEC_USE_COUNT;
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}
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static struct file_operations par_fops = {
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NULL, /* par_lseek */
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par_read, /* par_read */
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par_write, /* par_write */
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NULL, /* par_readdir */
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par_select, /* par_select */
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NULL, /* par_ioctl */
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NULL, /* par_mmap */
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par_open, /* par_open */
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par_release /* par_release */
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};
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#ifdef MODULE
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int init_module (void)
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{
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int i,sz,t,nports;
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if (register_chrdev(PAR_MAJOR,"par",&par_fops)) {
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printk("par: unable to get major %d\n", PAR_MAJOR);
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return -EIO;
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}
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nports = 0;
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for (i=0;i<NR_PAR;i++) {
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sz = (base[i] & 4) ? 3 : 8;
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if (check_region (base[i],sz))
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continue;
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outb (0,DATAPORT(i));
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udelay (50);
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t = inb (DATAPORT(i));
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if (t != 0)
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continue;
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exists[i]++;
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request_region (base[i],sz,"par");
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/* initialize state[i] with the current state of the hardware */
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state[i] = (((inb (DATAPORT(i)) & 0xff) ) |
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((inb (CTRLPORT(i)) & 0xff) << 8)) ^ INVERTEDOUTPUTS;
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nports++;
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printk ("par: port %d at 0x%3x. Current value: 0x%04x\n",
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i,base[i],state[i]);
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}
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update_rstate();
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return nports?0:-EIO;
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}
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void cleanup_module(void)
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{
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int i;
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int sz;
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/* Most modules don't check this it must be ok to continue anyway.... */
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if (MOD_IN_USE) {
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printk ("par module is still in use. Now what?\n");
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/* return; */
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}
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/* Don't forget this..... (BOOM) */
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if (nreaders)
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del_timer (&par_timer);
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unregister_chrdev(PAR_MAJOR,"par");
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for (i = 0; i < NR_PAR; i++) {
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sz = (base[i] & 4) ? 3 : 8;
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if (exists[i])
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release_region(base[i],sz);
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}
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printk ("par_cleanup: Bye bye...\n");
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}
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#else
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#warning I am not sure if you can compile this into the kernel.....
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#warning For instance the initialization is never called....
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#endif
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/*
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* Local variables:
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* compile-command: "cc -DMODULE -D__KERNEL__ -Wall -O2 -DEBUG -c par.c
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* tab-width: 8
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* End:
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*/
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Reference in New Issue
Block a user