baycom_par.c

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/*****************************************************************************/

/*
 *  baycom_par.c  -- baycom par96 and picpar radio modem driver.
 *
 *  Copyright (C) 1996-2000  Thomas Sailer ([email protected])
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *  Please note that the GPL allows you to use the driver, NOT the radio.
 *  In order to use the radio, you need a license from the communications
 *  authority of your country.
 *
 *
 *  Supported modems
 *
 *  par96:  This is a modem for 9600 baud FSK compatible to the G3RUH standard.
 *          The modem does all the filtering and regenerates the receiver clock.
 *          Data is transferred from and to the PC via a shift register.
 *          The shift register is filled with 16 bits and an interrupt is
 *          signalled. The PC then empties the shift register in a burst. This
 *          modem connects to the parallel port, hence the name. The modem
 *          leaves the implementation of the HDLC protocol and the scrambler
 *          polynomial to the PC. This modem is no longer available (at least
 *          from Baycom) and has been replaced by the PICPAR modem (see below).
 *          You may however still build one from the schematics published in
 *          cq-DL :-).
 *
 *  picpar: This is a redesign of the par96 modem by Henning Rech, DF9IC. The
 *          modem is protocol compatible to par96, but uses only three low
 *          power ICs and can therefore be fed from the parallel port and
 *          does not require an additional power supply. It features
 *          built in DCD circuitry. The driver should therefore be configured
 *          for hardware DCD.
 *
 *
 *  Command line options (insmod command line)
 *
 *  mode     driver mode string. Valid choices are par96 and picpar.
 *  iobase   base address of the port; common values are 0x378, 0x278, 0x3bc
 *
 *
 *  History:
 *   0.1  26.06.1996  Adapted from baycom.c and made network driver interface
 *        18.10.1996  Changed to new user space access routines (copy_{to,from}_user)
 *   0.3  26.04.1997  init code/data tagged
 *   0.4  08.07.1997  alternative ser12 decoding algorithm (uses delta CTS ints)
 *   0.5  11.11.1997  split into separate files for ser12/par96
 *   0.6  03.08.1999  adapt to Linus' new __setup/__initcall
 *                    removed some pre-2.2 kernel compatibility cruft
 *   0.7  10.08.1999  Check if parport can do SPP and is safe to access during interrupt contexts
 *   0.8  12.02.2000  adapted to softnet driver interface
 *                    removed direct parport access, uses parport driver methods
 *   0.9  03.07.2000  fix interface name handling
 */

/*****************************************************************************/

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/hdlcdrv.h>
#include <linux/baycom.h>
#include <linux/parport.h>
#include <linux/bitops.h>
#include <linux/jiffies.h>

#include <asm/uaccess.h>

/* --------------------------------------------------------------------- */

#define BAYCOM_DEBUG

/*
 * modem options; bit mask
 */
#define BAYCOM_OPTIONS_SOFTDCD  1

/* --------------------------------------------------------------------- */

static const char bc_drvname[] = "baycom_par";
static const char bc_drvinfo[] = KERN_INFO "baycom_par: (C) 1996-2000 Thomas Sailer, HB9JNX/AE4WA\n"
"baycom_par: version 0.9\n";

/* --------------------------------------------------------------------- */

#define NR_PORTS 4

static struct net_device *baycom_device[NR_PORTS];

/* --------------------------------------------------------------------- */

#define PAR96_BURSTBITS 16
#define PAR96_BURST     4
#define PAR96_PTT       2
#define PAR96_TXBIT     1
#define PAR96_ACK       0x40
#define PAR96_RXBIT     0x20
#define PAR96_DCD       0x10
#define PAR97_POWER     0xf8

/* ---------------------------------------------------------------------- */
/*
 * Information that need to be kept for each board.
 */

struct baycom_state {
    struct hdlcdrv_state hdrv;

    struct pardevice *pdev;
    unsigned int options;

    struct modem_state {
        short arb_divider;
        unsigned char flags;
        unsigned int shreg;
        struct modem_state_par96 {
            int dcd_count;
            unsigned int dcd_shreg;
            unsigned long descram;
            unsigned long scram;
        } par96;
    } modem;

#ifdef BAYCOM_DEBUG
    struct debug_vals {
        unsigned long last_jiffies;
        unsigned cur_intcnt;
        unsigned last_intcnt;
        int cur_pllcorr;
        int last_pllcorr;
    } debug_vals;
#endif /* BAYCOM_DEBUG */
};

/* --------------------------------------------------------------------- */

static void __inline__ baycom_int_freq(struct baycom_state *bc)
{
#ifdef BAYCOM_DEBUG
    unsigned long cur_jiffies = jiffies;
    /*
     * measure the interrupt frequency
     */
    bc->debug_vals.cur_intcnt++;
    if (time_after_eq(cur_jiffies, bc->debug_vals.last_jiffies + HZ)) {
        bc->debug_vals.last_jiffies = cur_jiffies;
        bc->debug_vals.last_intcnt = bc->debug_vals.cur_intcnt;
        bc->debug_vals.cur_intcnt = 0;
        bc->debug_vals.last_pllcorr = bc->debug_vals.cur_pllcorr;
        bc->debug_vals.cur_pllcorr = 0;
    }
#endif /* BAYCOM_DEBUG */
}

/* --------------------------------------------------------------------- */
/*
 * ===================== PAR96 specific routines =========================
 */

#define PAR96_DESCRAM_TAP1 0x20000
#define PAR96_DESCRAM_TAP2 0x01000
#define PAR96_DESCRAM_TAP3 0x00001

#define PAR96_DESCRAM_TAPSH1 17
#define PAR96_DESCRAM_TAPSH2 12
#define PAR96_DESCRAM_TAPSH3 0

#define PAR96_SCRAM_TAP1 0x20000 /* X^17 */
#define PAR96_SCRAM_TAPN 0x00021 /* X^0+X^5 */

/* --------------------------------------------------------------------- */

static __inline__ void par96_tx(struct net_device *dev, struct baycom_state *bc)
{
    int i;
    unsigned int data = hdlcdrv_getbits(&bc->hdrv);
    struct parport *pp = bc->pdev->port;

    for(i = 0; i < PAR96_BURSTBITS; i++, data >>= 1) {
        unsigned char val = PAR97_POWER;
        bc->modem.par96.scram = ((bc->modem.par96.scram << 1) |
                     (bc->modem.par96.scram & 1));
        if (!(data & 1))
            bc->modem.par96.scram ^= 1;
        if (bc->modem.par96.scram & (PAR96_SCRAM_TAP1 << 1))
            bc->modem.par96.scram ^=
                (PAR96_SCRAM_TAPN << 1);
        if (bc->modem.par96.scram & (PAR96_SCRAM_TAP1 << 2))
            val |= PAR96_TXBIT;
        pp->ops->write_data(pp, val);
        pp->ops->write_data(pp, val | PAR96_BURST);
    }
}

/* --------------------------------------------------------------------- */

static __inline__ void par96_rx(struct net_device *dev, struct baycom_state *bc)
{
    int i;
    unsigned int data, mask, mask2, descx;
    struct parport *pp = bc->pdev->port;

    /*
     * do receiver; differential decode and descramble on the fly
     */
    for(data = i = 0; i < PAR96_BURSTBITS; i++) {
        bc->modem.par96.descram = (bc->modem.par96.descram << 1);
        if (pp->ops->read_status(pp) & PAR96_RXBIT)
            bc->modem.par96.descram |= 1;
        descx = bc->modem.par96.descram ^
            (bc->modem.par96.descram >> 1);
        /* now the diff decoded data is inverted in descram */
        pp->ops->write_data(pp, PAR97_POWER | PAR96_PTT);
        descx ^= ((descx >> PAR96_DESCRAM_TAPSH1) ^
              (descx >> PAR96_DESCRAM_TAPSH2));
        data >>= 1;
        if (!(descx & 1))
            data |= 0x8000;
        pp->ops->write_data(pp, PAR97_POWER | PAR96_PTT | PAR96_BURST);
    }
    hdlcdrv_putbits(&bc->hdrv, data);
    /*
     * do DCD algorithm
     */
    if (bc->options & BAYCOM_OPTIONS_SOFTDCD) {
        bc->modem.par96.dcd_shreg = (bc->modem.par96.dcd_shreg >> 16)
            | (data << 16);
        /* search for flags and set the dcd counter appropriately */
        for(mask = 0x1fe00, mask2 = 0xfc00, i = 0;
            i < PAR96_BURSTBITS; i++, mask <<= 1, mask2 <<= 1)
            if ((bc->modem.par96.dcd_shreg & mask) == mask2)
                bc->modem.par96.dcd_count = HDLCDRV_MAXFLEN+4;
        /* check for abort/noise sequences */
        for(mask = 0x1fe00, mask2 = 0x1fe00, i = 0;
            i < PAR96_BURSTBITS; i++, mask <<= 1, mask2 <<= 1)
            if (((bc->modem.par96.dcd_shreg & mask) == mask2) &&
                (bc->modem.par96.dcd_count >= 0))
                bc->modem.par96.dcd_count -= HDLCDRV_MAXFLEN-10;
        /* decrement and set the dcd variable */
        if (bc->modem.par96.dcd_count >= 0)
            bc->modem.par96.dcd_count -= 2;
        hdlcdrv_setdcd(&bc->hdrv, bc->modem.par96.dcd_count > 0);
    } else {
        hdlcdrv_setdcd(&bc->hdrv, !!(pp->ops->read_status(pp) & PAR96_DCD));
    }
}

/* --------------------------------------------------------------------- */

static void par96_interrupt(void *dev_id)
{
    struct net_device *dev = dev_id;
    struct baycom_state *bc = netdev_priv(dev);

    baycom_int_freq(bc);
    /*
     * check if transmitter active
     */
    if (hdlcdrv_ptt(&bc->hdrv))
        par96_tx(dev, bc);
    else {
        par96_rx(dev, bc);
        if (--bc->modem.arb_divider <= 0) {
            bc->modem.arb_divider = 6;
            local_irq_enable();
            hdlcdrv_arbitrate(dev, &bc->hdrv);
        }
    }
    local_irq_enable();
    hdlcdrv_transmitter(dev, &bc->hdrv);
    hdlcdrv_receiver(dev, &bc->hdrv);
        local_irq_disable();
}

/* --------------------------------------------------------------------- */

static void par96_wakeup(void *handle)
{
        struct net_device *dev = (struct net_device *)handle;
    struct baycom_state *bc = netdev_priv(dev);

    printk(KERN_DEBUG "baycom_par: %s: why am I being woken up?\n", dev->name);
    if (!parport_claim(bc->pdev))
        printk(KERN_DEBUG "baycom_par: %s: I'm broken.\n", dev->name);
}

/* --------------------------------------------------------------------- */

static int par96_open(struct net_device *dev)
{
    struct baycom_state *bc = netdev_priv(dev);
    struct parport *pp;

    if (!dev || !bc)
        return -ENXIO;
    pp = parport_find_base(dev->base_addr);
    if (!pp) {
        printk(KERN_ERR "baycom_par: parport at 0x%lx unknown\n", dev->base_addr);
        return -ENXIO;
    }
    if (pp->irq < 0) {
        printk(KERN_ERR "baycom_par: parport at 0x%lx has no irq\n", pp->base);
        parport_put_port(pp);
        return -ENXIO;
    }
    if ((~pp->modes) & (PARPORT_MODE_PCSPP | PARPORT_MODE_SAFEININT)) {
        printk(KERN_ERR "baycom_par: parport at 0x%lx cannot be used\n", pp->base);
        parport_put_port(pp);
        return -ENXIO;
    }
    memset(&bc->modem, 0, sizeof(bc->modem));
    bc->hdrv.par.bitrate = 9600;
    bc->pdev = parport_register_device(pp, dev->name, NULL, par96_wakeup, 
                 par96_interrupt, PARPORT_DEV_EXCL, dev);
    parport_put_port(pp);
    if (!bc->pdev) {
        printk(KERN_ERR "baycom_par: cannot register parport at 0x%lx\n", dev->base_addr);
        return -ENXIO;
    }
    if (parport_claim(bc->pdev)) {
        printk(KERN_ERR "baycom_par: parport at 0x%lx busy\n", pp->base);
        parport_unregister_device(bc->pdev);
        return -EBUSY;
    }
    pp = bc->pdev->port;
    dev->irq = pp->irq;
    pp->ops->data_forward(pp);
        bc->hdrv.par.bitrate = 9600;
    pp->ops->write_data(pp, PAR96_PTT | PAR97_POWER); /* switch off PTT */
    pp->ops->enable_irq(pp);
    printk(KERN_INFO "%s: par96 at iobase 0x%lx irq %u options 0x%x\n",
           bc_drvname, dev->base_addr, dev->irq, bc->options);
    return 0;
}

/* --------------------------------------------------------------------- */

static int par96_close(struct net_device *dev)
{
    struct baycom_state *bc = netdev_priv(dev);
    struct parport *pp;

    if (!dev || !bc)
        return -EINVAL;
    pp = bc->pdev->port;
    /* disable interrupt */
    pp->ops->disable_irq(pp);
    /* switch off PTT */
    pp->ops->write_data(pp, PAR96_PTT | PAR97_POWER);
    parport_release(bc->pdev);
    parport_unregister_device(bc->pdev);
    printk(KERN_INFO "%s: close par96 at iobase 0x%lx irq %u\n",
           bc_drvname, dev->base_addr, dev->irq);
    return 0;
}

/* --------------------------------------------------------------------- */
/*
 * ===================== hdlcdrv driver interface =========================
 */

static int baycom_ioctl(struct net_device *dev, struct ifreq *ifr,
            struct hdlcdrv_ioctl *hi, int cmd);

/* --------------------------------------------------------------------- */

static struct hdlcdrv_ops par96_ops = {
    .drvname = bc_drvname,
    .drvinfo = bc_drvinfo,
    .open    = par96_open,
    .close   = par96_close,
    .ioctl   = baycom_ioctl
};

/* --------------------------------------------------------------------- */

static int baycom_setmode(struct baycom_state *bc, const char *modestr)
{
    if (!strncmp(modestr, "picpar", 6))
        bc->options = 0;
    else if (!strncmp(modestr, "par96", 5))
        bc->options = BAYCOM_OPTIONS_SOFTDCD;
    else
        bc->options = !!strchr(modestr, '*');
    return 0;
}

/* --------------------------------------------------------------------- */

static int baycom_ioctl(struct net_device *dev, struct ifreq *ifr,
            struct hdlcdrv_ioctl *hi, int cmd)
{
    struct baycom_state *bc;
    struct baycom_ioctl bi;

    if (!dev)
        return -EINVAL;

    bc = netdev_priv(dev);
    BUG_ON(bc->hdrv.magic != HDLCDRV_MAGIC);

    if (cmd != SIOCDEVPRIVATE)
        return -ENOIOCTLCMD;
    switch (hi->cmd) {
    default:
        break;

    case HDLCDRVCTL_GETMODE:
        strcpy(hi->data.modename, bc->options ? "par96" : "picpar");
        if (copy_to_user(ifr->ifr_data, hi, sizeof(struct hdlcdrv_ioctl)))
            return -EFAULT;
        return 0;

    case HDLCDRVCTL_SETMODE:
        if (netif_running(dev) || !capable(CAP_NET_ADMIN))
            return -EACCES;
        hi->data.modename[sizeof(hi->data.modename)-1] = '\0';
        return baycom_setmode(bc, hi->data.modename);

    case HDLCDRVCTL_MODELIST:
        strcpy(hi->data.modename, "par96,picpar");
        if (copy_to_user(ifr->ifr_data, hi, sizeof(struct hdlcdrv_ioctl)))
            return -EFAULT;
        return 0;

    case HDLCDRVCTL_MODEMPARMASK:
        return HDLCDRV_PARMASK_IOBASE;

    }

    if (copy_from_user(&bi, ifr->ifr_data, sizeof(bi)))
        return -EFAULT;
    switch (bi.cmd) {
    default:
        return -ENOIOCTLCMD;

#ifdef BAYCOM_DEBUG
    case BAYCOMCTL_GETDEBUG:
        bi.data.dbg.debug1 = bc->hdrv.ptt_keyed;
        bi.data.dbg.debug2 = bc->debug_vals.last_intcnt;
        bi.data.dbg.debug3 = bc->debug_vals.last_pllcorr;
        break;
#endif /* BAYCOM_DEBUG */

    }
    if (copy_to_user(ifr->ifr_data, &bi, sizeof(bi)))
        return -EFAULT;
    return 0;

}

/* --------------------------------------------------------------------- */

/*
 * command line settable parameters
 */
static char *mode[NR_PORTS] = { "picpar", };
static int iobase[NR_PORTS] = { 0x378, };

module_param_array(mode, charp, NULL, 0);
MODULE_PARM_DESC(mode, "baycom operating mode; eg. par96 or picpar");
module_param_array(iobase, int, NULL, 0);
MODULE_PARM_DESC(iobase, "baycom io base address");

MODULE_AUTHOR("Thomas M. Sailer, [email protected], [email protected]");
MODULE_DESCRIPTION("Baycom par96 and picpar amateur radio modem driver");
MODULE_LICENSE("GPL");

/* --------------------------------------------------------------------- */

static int __init init_baycompar(void)
{
    int i, found = 0;
    char set_hw = 1;

    printk(bc_drvinfo);
    /*
     * register net devices
     */
    for (i = 0; i < NR_PORTS; i++) {
        struct net_device *dev;
        struct baycom_state *bc;
        char ifname[IFNAMSIZ];

        sprintf(ifname, "bcp%d", i);

        if (!mode[i])
            set_hw = 0;
        if (!set_hw)
            iobase[i] = 0;

        dev = hdlcdrv_register(&par96_ops,
                       sizeof(struct baycom_state),
                       ifname, iobase[i], 0, 0);
        if (IS_ERR(dev)) 
            break;

        bc = netdev_priv(dev);
        if (set_hw && baycom_setmode(bc, mode[i]))
            set_hw = 0;
        found++;
        baycom_device[i] = dev;
    }

    if (!found)
        return -ENXIO;
    return 0;
}

static void __exit cleanup_baycompar(void)
{
    int i;

    for(i = 0; i < NR_PORTS; i++) {
        struct net_device *dev = baycom_device[i];

        if (dev)
            hdlcdrv_unregister(dev);
    }
}

module_init(init_baycompar);
module_exit(cleanup_baycompar);

/* --------------------------------------------------------------------- */

#ifndef MODULE

/*
 * format: baycom_par=io,mode
 * mode: par96,picpar
 */

static int __init baycom_par_setup(char *str)
{
        static unsigned nr_dev;
    int ints[2];

        if (nr_dev >= NR_PORTS)
                return 0;
        str = get_options(str, 2, ints);
        if (ints[0] < 1)
                return 0;
        mode[nr_dev] = str;
        iobase[nr_dev] = ints[1];
    nr_dev++;
    return 1;
}

__setup("baycom_par=", baycom_par_setup);

#endif /* MODULE */
/* --------------------------------------------------------------------- */