baycom_epp.c

linux-2.6.15.6

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

/*
 *	baycom_epp.c  -- baycom epp radio modem driver.
 *
 *	Copyright (C) 1998-2000
 *          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.
 *
 *
 *  History:
 *   0.1  xx.xx.1998  Initial version by Matthias Welwarsky (dg2fef)
 *   0.2  21.04.1998  Massive rework by Thomas Sailer
 *                    Integrated FPGA EPP modem configuration routines
 *   0.3  11.05.1998  Took FPGA config out and moved it into a separate program
 *   0.4  26.07.1999  Adapted to new lowlevel parport driver interface
 *   0.5  03.08.1999  adapt to Linus' new __setup/__initcall
 *                    removed some pre-2.2 kernel compatibility cruft
 *   0.6  10.08.1999  Check if parport can do SPP and is safe to access during interrupt contexts
 *   0.7  12.02.2000  adapted to softnet driver interface
 *
 */

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

#include <linux/crc-ccitt.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/workqueue.h>
#include <linux/fs.h>
#include <linux/parport.h>
#include <linux/if_arp.h>
#include <linux/hdlcdrv.h>
#include <linux/baycom.h>
#include <linux/jiffies.h>
#include <net/ax25.h> 
#include <asm/uaccess.h>

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

#define BAYCOM_DEBUG
#define BAYCOM_MAGIC 19730510

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

static const char paranoia_str[] = KERN_ERR 
	"baycom_epp: bad magic number for hdlcdrv_state struct in routine %s\n";

static const char bc_drvname[] = "baycom_epp";
static const char bc_drvinfo[] = KERN_INFO "baycom_epp: (C) 1998-2000 Thomas Sailer, HB9JNX/AE4WA\n"
KERN_INFO "baycom_epp: version 0.7 compiled " __TIME__ " " __DATE__ "\n";

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

#define NR_PORTS 4

static struct net_device *baycom_device[NR_PORTS];

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

/* EPP status register */
#define EPP_DCDBIT      0x80
#define EPP_PTTBIT      0x08
#define EPP_NREF        0x01
#define EPP_NRAEF       0x02
#define EPP_NRHF        0x04
#define EPP_NTHF        0x20
#define EPP_NTAEF       0x10
#define EPP_NTEF        EPP_PTTBIT

/* EPP control register */
#define EPP_TX_FIFO_ENABLE 0x10
#define EPP_RX_FIFO_ENABLE 0x08
#define EPP_MODEM_ENABLE   0x20
#define EPP_LEDS           0xC0
#define EPP_IRQ_ENABLE     0x10

/* LPT registers */
#define LPTREG_ECONTROL       0x402
#define LPTREG_CONFIGB        0x401
#define LPTREG_CONFIGA        0x400
#define LPTREG_EPPDATA        0x004
#define LPTREG_EPPADDR        0x003
#define LPTREG_CONTROL        0x002
#define LPTREG_STATUS         0x001
#define LPTREG_DATA           0x000

/* LPT control register */
#define LPTCTRL_PROGRAM       0x04   /* 0 to reprogram */
#define LPTCTRL_WRITE         0x01
#define LPTCTRL_ADDRSTB       0x08
#define LPTCTRL_DATASTB       0x02
#define LPTCTRL_INTEN         0x10

/* LPT status register */
#define LPTSTAT_SHIFT_NINTR   6
#define LPTSTAT_WAIT          0x80
#define LPTSTAT_NINTR         (1<<LPTSTAT_SHIFT_NINTR)
#define LPTSTAT_PE            0x20
#define LPTSTAT_DONE          0x10
#define LPTSTAT_NERROR        0x08
#define LPTSTAT_EPPTIMEOUT    0x01

/* LPT data register */
#define LPTDATA_SHIFT_TDI     0
#define LPTDATA_SHIFT_TMS     2
#define LPTDATA_TDI           (1<<LPTDATA_SHIFT_TDI)
#define LPTDATA_TCK           0x02
#define LPTDATA_TMS           (1<<LPTDATA_SHIFT_TMS)
#define LPTDATA_INITBIAS      0x80


/* EPP modem config/status bits */
#define EPP_DCDBIT            0x80
#define EPP_PTTBIT            0x08
#define EPP_RXEBIT            0x01
#define EPP_RXAEBIT           0x02
#define EPP_RXHFULL           0x04

#define EPP_NTHF              0x20
#define EPP_NTAEF             0x10
#define EPP_NTEF              EPP_PTTBIT

#define EPP_TX_FIFO_ENABLE    0x10
#define EPP_RX_FIFO_ENABLE    0x08
#define EPP_MODEM_ENABLE      0x20
#define EPP_LEDS              0xC0
#define EPP_IRQ_ENABLE        0x10

/* Xilinx 4k JTAG instructions */
#define XC4K_IRLENGTH   3
#define XC4K_EXTEST     0
#define XC4K_PRELOAD    1
#define XC4K_CONFIGURE  5
#define XC4K_BYPASS     7

#define EPP_CONVENTIONAL  0
#define EPP_FPGA          1
#define EPP_FPGAEXTSTATUS 2

#define TXBUFFER_SIZE     ((HDLCDRV_MAXFLEN*6/5)+8)

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

struct baycom_state {
	int magic;

        struct pardevice *pdev;
	unsigned int work_running;
	struct work_struct run_work;
	unsigned int modem;
	unsigned int bitrate;
	unsigned char stat;

	struct {
		unsigned int intclk;
		unsigned int fclk;
		unsigned int bps;
		unsigned int extmodem;
		unsigned int loopback;
	} cfg;

        struct hdlcdrv_channel_params ch_params;

        struct {
		unsigned int bitbuf, bitstream, numbits, state;
		unsigned char *bufptr;
		int bufcnt;
		unsigned char buf[TXBUFFER_SIZE];
        } hdlcrx;

        struct {
		int calibrate;
                int slotcnt;
		int flags;
		enum { tx_idle = 0, tx_keyup, tx_data, tx_tail } state;
		unsigned char *bufptr;
		int bufcnt;
		unsigned char buf[TXBUFFER_SIZE];
        } hdlctx;

        struct net_device_stats stats;
	unsigned int ptt_keyed;
	struct sk_buff *skb;  /* next transmit packet  */

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

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

#define KISS_VERBOSE

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

#define PARAM_TXDELAY   1
#define PARAM_PERSIST   2
#define PARAM_SLOTTIME  3
#define PARAM_TXTAIL    4
#define PARAM_FULLDUP   5
#define PARAM_HARDWARE  6
#define PARAM_RETURN    255

/* --------------------------------------------------------------------- */
/*
 * the CRC routines are stolen from WAMPES
 * by Dieter Deyke
 */


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

#if 0
static inline void append_crc_ccitt(unsigned char *buffer, int len)
{
 	unsigned int crc = 0xffff;

	for (;len>0;len--)
		crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buffer++) & 0xff];
	crc ^= 0xffff;
	*buffer++ = crc;
	*buffer++ = crc >> 8;
}
#endif

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

static inline int check_crc_ccitt(const unsigned char *buf, int cnt)
{
	return (crc_ccitt(0xffff, buf, cnt) & 0xffff) == 0xf0b8;
}

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

static inline int calc_crc_ccitt(const unsigned char *buf, int cnt)
{
	return (crc_ccitt(0xffff, buf, cnt) ^ 0xffff) & 0xffff;
}

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

#define tenms_to_flags(bc,tenms) ((tenms * bc->bitrate) / 800)

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

static inline void 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 */
}

/* ---------------------------------------------------------------------- */
/*
 *    eppconfig_path should be setable  via /proc/sys.
 */

static char eppconfig_path[256] = "/usr/sbin/eppfpga";

static char *envp[] = { "HOME=/", "TERM=linux", "PATH=/usr/bin:/bin", NULL };

/* eppconfig: called during ifconfig up to configure the modem */
static int eppconfig(struct baycom_state *bc)
{
	char modearg[256];
	char portarg[16];
        char *argv[] = { eppconfig_path, "-s", "-p", portarg, "-m", modearg,
			 NULL };

	/* set up arguments */
	sprintf(modearg, "%sclk,%smodem,fclk=%d,bps=%d,divider=%d%s,extstat",
		bc->cfg.intclk ? "int" : "ext",
		bc->cfg.extmodem ? "ext" : "int", bc->cfg.fclk, bc->cfg.bps,
		(bc->cfg.fclk + 8 * bc->cfg.bps) / (16 * bc->cfg.bps),
		bc->cfg.loopback ? ",loopback" : "");
	sprintf(portarg, "%ld", bc->pdev->port->base);
	printk(KERN_DEBUG "%s: %s -s -p %s -m %s\n", bc_drvname, eppconfig_path, portarg, modearg);

	return call_usermodehelper(eppconfig_path, argv, envp, 1);
}

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

static void epp_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
}

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

static inline void do_kiss_params(struct baycom_state *bc,
				  unsigned char *data, unsigned long len)
{

#ifdef KISS_VERBOSE
#define PKP(a,b) printk(KERN_INFO "baycomm_epp: channel params: " a "\n", b)
#else /* KISS_VERBOSE */	      
#define PKP(a,b) 
#endif /* KISS_VERBOSE */	      

	if (len < 2)
		return;
	switch(data[0]) {
	case PARAM_TXDELAY:
		bc->ch_params.tx_delay = data[1];
		PKP("TX delay = %ums", 10 * bc->ch_params.tx_delay);
		break;
	case PARAM_PERSIST:   
		bc->ch_params.ppersist = data[1];
		PKP("p persistence = %u", bc->ch_params.ppersist);
		break;
	case PARAM_SLOTTIME:  
		bc->ch_params.slottime = data[1];
		PKP("slot time = %ums", bc->ch_params.slottime);
		break;
	case PARAM_TXTAIL:    
		bc->ch_params.tx_tail = data[1];
		PKP("TX tail = %ums", bc->ch_params.tx_tail);
		break;
	case PARAM_FULLDUP:   
		bc->ch_params.fulldup = !!data[1];
		PKP("%s duplex", bc->ch_params.fulldup ? "full" : "half");
		break;
	default:
		break;
	}
#undef PKP
}

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

static void encode_hdlc(struct baycom_state *bc)
{
	struct sk_buff *skb;
	unsigned char *wp, *bp;
	int pkt_len;
        unsigned bitstream, notbitstream, bitbuf, numbit, crc;
	unsigned char crcarr[2];
	int j;
	
	if (bc->hdlctx.bufcnt > 0)
		return;
	skb = bc->skb;
	if (!skb)
		return;
	bc->skb = NULL;
	pkt_len = skb->len-1; /* strip KISS byte */
	wp = bc->hdlctx.buf;
	bp = skb->data+1;
	crc = calc_crc_ccitt(bp, pkt_len);
	crcarr[0] = crc;
	crcarr[1] = crc >> 8;
	*wp++ = 0x7e;
	bitstream = bitbuf = numbit = 0;
	while (pkt_len > -2) {
		bitstream >>= 8;
		bitstream |= ((unsigned int)*bp) << 8;
		bitbuf |= ((unsigned int)*bp) << numbit;
		notbitstream = ~bitstream;
		bp++;
		pkt_len--;
		if (!pkt_len)
			bp = crcarr;
		for (j = 0; j < 8; j++)
			if (unlikely(!(notbitstream & (0x1f0 << j)))) {
				bitstream &= ~(0x100 << j);
 				bitbuf = (bitbuf & (((2 << j) << numbit) - 1)) |
					((bitbuf & ~(((2 << j) << numbit) - 1)) << 1);
				numbit++;
				notbitstream = ~bitstream;
			}
		numbit += 8;
		while (numbit >= 8) {
			*wp++ = bitbuf;
			bitbuf >>= 8;
			numbit -= 8;
		}
	}
	bitbuf |= 0x7e7e << numbit;
	numbit += 16;
	while (numbit >= 8) {
		*wp++ = bitbuf;
		bitbuf >>= 8;
		numbit -= 8;
	}
	bc->hdlctx.bufptr = bc->hdlctx.buf;
	bc->hdlctx.bufcnt = wp - bc->hdlctx.buf;
	dev_kfree_skb(skb);
	bc->stats.tx_packets++;
}

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

static unsigned short random_seed;

static inline unsigned short random_num(void)
{
	random_seed = 28629 * random_seed + 157;