baycom_ser_fdx.c

linux-2.4.29操作系统的源码

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

/*
 *	baycom_ser_fdx.c  -- baycom ser12 fullduplex radio modem driver.
 *
 *	Copyright (C) 1996-2000  Thomas Sailer ([e-mail])
 *
 *	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
 *
 *  ser12:  This is a very simple 1200 baud AFSK modem. The modem consists only
 *          of a modulator/demodulator chip, usually a TI TCM3105. The computer
 *          is responsible for regenerating the receiver bit clock, as well as
 *          for handling the HDLC protocol. The modem connects to a serial port,
 *          hence the name. Since the serial port is not used as an async serial
 *          port, the kernel driver for serial ports cannot be used, and this
 *          driver only supports standard serial hardware (8250, 16450, 16550A)
 *
 *          This modem usually draws its supply current out of the otherwise unused
 *          TXD pin of the serial port. Thus a contignuous stream of 0x00-bytes
 *          is transmitted to achieve a positive supply voltage.
 *
 *  hsk:    This is a 4800 baud FSK modem, designed for TNC use. It works fine
 *          in 'baycom-mode' :-)  In contrast to the TCM3105 modem, power is
 *          externally supplied. So there's no need to provide the 0x00-byte-stream
 *          when receiving or idle, which drastically reduces interrupt load.
 *
 *  Command line options (insmod command line)
 *
 *  mode     ser#    hardware DCD
 *           ser#*   software DCD
 *           ser#+   hardware DCD, inverted signal at DCD pin
 *           '#' denotes the baud rate / 100, eg. ser12* is '1200 baud, soft DCD'
 *  iobase   base address of the port; common values are 0x3f8, 0x2f8, 0x3e8, 0x2e8
 *  baud     baud rate (between 300 and 4800)
 *  irq      interrupt line of the port; common values are 4,3
 *
 *
 *  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  ser12/par96 split into separate files
 *   0.6  24.01.1998  Thorsten Kranzkowski, dl8bcu and Thomas Sailer:
 *                    reduced interrupt load in transmit case
 *                    reworked receiver
 *   0.7  03.08.1999  adapt to Linus' new __setup/__initcall
 *   0.8  10.08.1999  use module_init/module_exit
 *   0.9  12.02.2000  adapted to softnet driver interface
 *   0.10 03.07.2000  fix interface name handling
 */

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

#include <linux/version.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/string.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/hdlcdrv.h>
#include <linux/baycom.h>

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

#define BAYCOM_DEBUG

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

static const char bc_drvname[] = "baycom_ser_fdx";
static const char bc_drvinfo[] = KERN_INFO "baycom_ser_fdx: (C) 1996-2000 Thomas Sailer, HB9JNX/AE4WA\n"
KERN_INFO "baycom_ser_fdx: version 0.10 compiled " __TIME__ " " __DATE__ "\n";

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

#define NR_PORTS 4

static struct net_device baycom_device[NR_PORTS];

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

#define RBR(iobase) (iobase+0)
#define THR(iobase) (iobase+0)
#define IER(iobase) (iobase+1)
#define IIR(iobase) (iobase+2)
#define FCR(iobase) (iobase+2)
#define LCR(iobase) (iobase+3)
#define MCR(iobase) (iobase+4)
#define LSR(iobase) (iobase+5)
#define MSR(iobase) (iobase+6)
#define SCR(iobase) (iobase+7)
#define DLL(iobase) (iobase+0)
#define DLM(iobase) (iobase+1)

#define SER12_EXTENT 8

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

struct baycom_state {
	struct hdlcdrv_state hdrv;

	unsigned int baud, baud_us, baud_arbdiv, baud_uartdiv, baud_dcdtimeout;
	int opt_dcd;

	struct modem_state {
		unsigned char flags;
		unsigned char ptt;
		unsigned int shreg;
		struct modem_state_ser12 {
			unsigned char tx_bit;
			unsigned char last_rxbit;
			int dcd_sum0, dcd_sum1, dcd_sum2;
			int dcd_time;
			unsigned int pll_time;
			unsigned int txshreg;
		} ser12;
	} 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 ((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 */
}

/* --------------------------------------------------------------------- */
/*
 * ===================== SER12 specific routines =========================
 */

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

static inline void ser12_set_divisor(struct net_device *dev,
                                     unsigned int divisor)
{
        outb(0x81, LCR(dev->base_addr));        /* DLAB = 1 */
        outb(divisor, DLL(dev->base_addr));
        outb(divisor >> 8, DLM(dev->base_addr));
        outb(0x01, LCR(dev->base_addr));        /* word length = 6 */
        /*
         * make sure the next interrupt is generated;
         * 0 must be used to power the modem; the modem draws its
         * power from the TxD line
         */
        outb(0x00, THR(dev->base_addr));
        /*
         * it is important not to set the divider while transmitting;
         * this reportedly makes some UARTs generating interrupts
         * in the hundredthousands per second region
         * Reported by: [e-mail] (Ignacio Arenaza Nuno)
         */
}

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

#if 0
static inline unsigned int hweight16(unsigned int w)
        __attribute__ ((unused));
static inline unsigned int hweight8(unsigned int w)
        __attribute__ ((unused));

static inline unsigned int hweight16(unsigned int w)
{
        unsigned short res = (w & 0x5555) + ((w >> 1) & 0x5555);
        res = (res & 0x3333) + ((res >> 2) & 0x3333);
        res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F);
        return (res & 0x00FF) + ((res >> 8) & 0x00FF);
}

static inline unsigned int hweight8(unsigned int w)
{
        unsigned short res = (w & 0x55) + ((w >> 1) & 0x55);
        res = (res & 0x33) + ((res >> 2) & 0x33);
        return (res & 0x0F) + ((res >> 4) & 0x0F);
}
#endif

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

static __inline__ void ser12_rx(struct net_device *dev, struct baycom_state *bc, struct timeval *tv, unsigned char curs)
{
	int timediff;
	int bdus8 = bc->baud_us >> 3;
	int bdus4 = bc->baud_us >> 2;
	int bdus2 = bc->baud_us >> 1;

	timediff = 1000000 + tv->tv_usec - bc->modem.ser12.pll_time;
	while (timediff >= 500000)
		timediff -= 1000000;
	while (timediff >= bdus2) {
		timediff -= bc->baud_us;
		bc->modem.ser12.pll_time += bc->baud_us;
		bc->modem.ser12.dcd_time--;
		/* first check if there is room to add a bit */
		if (bc->modem.shreg & 1) {
			hdlcdrv_putbits(&bc->hdrv, (bc->modem.shreg >> 1) ^ 0xffff);
			bc->modem.shreg = 0x10000;
		}
		/* add a one bit */
		bc->modem.shreg >>= 1;
	}
	if (bc->modem.ser12.dcd_time <= 0) {
		if (!bc->opt_dcd)
			hdlcdrv_setdcd(&bc->hdrv, (bc->modem.ser12.dcd_sum0 + 
						   bc->modem.ser12.dcd_sum1 + 
						   bc->modem.ser12.dcd_sum2) < 0);
		bc->modem.ser12.dcd_sum2 = bc->modem.ser12.dcd_sum1;
		bc->modem.ser12.dcd_sum1 = bc->modem.ser12.dcd_sum0;
		bc->modem.ser12.dcd_sum0 = 2; /* slight bias */
		bc->modem.ser12.dcd_time += 120;
	}
	if (bc->modem.ser12.last_rxbit != curs) {
		bc->modem.ser12.last_rxbit = curs;
		bc->modem.shreg |= 0x10000;
		/* adjust the PLL */
		if (timediff > 0)
			bc->modem.ser12.pll_time += bdus8;
		else
			bc->modem.ser12.pll_time += 1000000 - bdus8;
		/* update DCD */
		if (abs(timediff) > bdus4)
			bc->modem.ser12.dcd_sum0 += 4;
		else
			bc->modem.ser12.dcd_sum0--;
#ifdef BAYCOM_DEBUG
		bc->debug_vals.cur_pllcorr = timediff;
#endif /* BAYCOM_DEBUG */
	}
	while (bc->modem.ser12.pll_time >= 1000000)
		bc->modem.ser12.pll_time -= 1000000;
}

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

static void ser12_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	struct net_device *dev = (struct net_device *)dev_id;
	struct baycom_state *bc = (struct baycom_state *)dev->priv;
	struct timeval tv;
	unsigned char iir, msr;
	unsigned int txcount = 0;

	if (!bc || bc->hdrv.magic != HDLCDRV_MAGIC)
		return;
	/* fast way out for shared irq */
	if ((iir = inb(IIR(dev->base_addr))) & 1) 	
		return;
	/* get current time */
	do_gettimeofday(&tv);
	msr = inb(MSR(dev->base_addr));
	/* delta DCD */
	if ((msr & 8) && bc->opt_dcd)
		hdlcdrv_setdcd(&bc->hdrv, !((msr ^ bc->opt_dcd) & 0x80));
	do {
		switch (iir & 6) {
		case 6:
			inb(LSR(dev->base_addr));
			break;
			
		case 4:
			inb(RBR(dev->base_addr));
			break;
			
		case 2:
			/*
			 * make sure the next interrupt is generated;
			 * 0 must be used to power the modem; the modem draws its
			 * power from the TxD line
			 */
			outb(0x00, THR(dev->base_addr));
			baycom_int_freq(bc);
			txcount++;
			/*
			 * first output the last bit (!) then call HDLC transmitter,
			 * since this may take quite long
			 */
			if (bc->modem.ptt)
				outb(0x0e | (!!bc->modem.ser12.tx_bit), MCR(dev->base_addr));
			else
				outb(0x0d, MCR(dev->base_addr));       /* transmitter off */
			break;
			
		default:
			msr = inb(MSR(dev->base_addr));
			/* delta DCD */
			if ((msr & 8) && bc->opt_dcd) 
				hdlcdrv_setdcd(&bc->hdrv, !((msr ^ bc->opt_dcd) & 0x80));
			break;
		}
		iir = inb(IIR(dev->base_addr));
	} while (!(iir & 1));
	ser12_rx(dev, bc, &tv, msr & 0x10); /* CTS */
	if (bc->modem.ptt && txcount) {
		if (bc->modem.ser12.txshreg <= 1) {
			bc->modem.ser12.txshreg = 0x10000 | hdlcdrv_getbits(&bc->hdrv);
			if (!hdlcdrv_ptt(&bc->hdrv)) {
				ser12_set_divisor(dev, 115200/100/8);
				bc->modem.ptt = 0;
				goto end_transmit;
			}
		}
		bc->modem.ser12.tx_bit = !(bc->modem.ser12.tx_bit ^ (bc->modem.ser12.txshreg & 1));
		bc->modem.ser12.txshreg >>= 1;
	}
 end_transmit:
	__sti();
	if (!bc->modem.ptt && txcount) {
		hdlcdrv_arbitrate(dev, &bc->hdrv);
		if (hdlcdrv_ptt(&bc->hdrv)) {
			ser12_set_divisor(dev, bc->baud_uartdiv);
			bc->modem.ser12.txshreg = 1;