garmin_gps.c

LINUX 2.6.17.4的源码

/*
 * Garmin GPS driver
 *
 * Copyright (C) 2004 Hermann Kneissel [e-mail]
 *
 * The latest version of the driver can be found at
 * http://sourceforge.net/projects/garmin-gps/
 *
 * This driver has been derived from v2.1 of the visor driver.
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA 02111 USA
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
#include <linux/usb.h>

/* the mode to be set when the port ist opened */
static int initial_mode = 1;

/* debug flag */
static int debug = 0;

#include "usb-serial.h"

#define GARMIN_VENDOR_ID             0x091E

/*
 * Version Information
 */

#define VERSION_MAJOR	0
#define VERSION_MINOR	23

#define _STR(s) #s
#define _DRIVER_VERSION(a,b) "v" _STR(a) "." _STR(b)
#define DRIVER_VERSION _DRIVER_VERSION(VERSION_MAJOR, VERSION_MINOR)
#define DRIVER_AUTHOR "hermann kneissel"
#define DRIVER_DESC "garmin gps driver"

/* error codes returned by the driver */
#define EINVPKT	1000	/* invalid packet structure */


// size of the header of a packet using the usb protocol
#define GARMIN_PKTHDR_LENGTH	12

// max. possible size of a packet using the serial protocol 
#define MAX_SERIAL_PKT_SIZ (3+255+3)

// max. possible size of a packet with worst case stuffing
#define MAX_SERIAL_PKT_SIZ_STUFFED MAX_SERIAL_PKT_SIZ+256

// size of a buffer able to hold a complete (no stuffing) packet
// (the document protocol does not contain packets with a larger
//  size, but in theory a packet may be 64k+12 bytes - if in
//  later protocol versions larger packet sizes occur, this value
//  should be increased accordingly, so the input buffer is always 
//  large enough the store a complete packet inclusive header)
#define GPS_IN_BUFSIZ  (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ) 

// size of a buffer able to hold a complete (incl. stuffing) packet
#define GPS_OUT_BUFSIZ (GARMIN_PKTHDR_LENGTH+MAX_SERIAL_PKT_SIZ_STUFFED) 

// where to place the packet id of a serial packet, so we can
// prepend the usb-packet header without the need to move the
// packets data
#define GSP_INITIAL_OFFSET (GARMIN_PKTHDR_LENGTH-2)

// max. size of incoming private packets (header+1 param)
#define PRIVPKTSIZ (GARMIN_PKTHDR_LENGTH+4)

#define GARMIN_LAYERID_TRANSPORT  0
#define GARMIN_LAYERID_APPL      20
// our own layer-id to use for some control mechanisms
#define GARMIN_LAYERID_PRIVATE	0x01106E4B

#define GARMIN_PKTID_PVT_DATA	51
#define GARMIN_PKTID_L001_COMMAND_DATA 10

#define CMND_ABORT_TRANSFER 0

// packet ids used in private layer
#define PRIV_PKTID_SET_DEBUG	1
#define PRIV_PKTID_SET_MODE	2
#define PRIV_PKTID_INFO_REQ	3
#define PRIV_PKTID_INFO_RESP	4
#define PRIV_PKTID_RESET_REQ	5
#define PRIV_PKTID_SET_DEF_MODE	6


#define ETX	0x03
#define DLE	0x10
#define ACK	0x06
#define NAK	0x15

/* structure used to queue incoming packets */
struct garmin_packet {
	struct list_head  list;
	int               seq;
	int               size; // the real size of the data array, always > 0
	__u8              data[1];
};

/* structure used to keep the current state of the driver */
struct garmin_data {
	__u8   state;
	__u16  flags;
	__u8   mode;
	__u8   ignorePkts;
	__u8   count;
	__u8   pkt_id;
	__u32  serial_num;
	struct timer_list timer;
	struct usb_serial_port *port;
	int    seq_counter;
	int    insize;
	int    outsize;
	__u8   inbuffer [GPS_IN_BUFSIZ];  /* tty -> usb */
	__u8   outbuffer[GPS_OUT_BUFSIZ]; /* usb -> tty */
	__u8   privpkt[4*6];
	spinlock_t lock;
	struct list_head pktlist;
};


#define STATE_NEW            0
#define STATE_INITIAL_DELAY  1
#define STATE_TIMEOUT        2
#define STATE_SESSION_REQ1   3
#define STATE_SESSION_REQ2   4
#define STATE_ACTIVE         5

#define STATE_RESET	     8
#define STATE_DISCONNECTED   9
#define STATE_WAIT_TTY_ACK  10
#define STATE_GSP_WAIT_DATA 11

#define MODE_NATIVE          0
#define MODE_GARMIN_SERIAL   1

// Flags used in garmin_data.flags:
#define FLAGS_SESSION_REPLY_MASK  0x00C0
#define FLAGS_SESSION_REPLY1_SEEN 0x0080
#define FLAGS_SESSION_REPLY2_SEEN 0x0040
#define FLAGS_BULK_IN_ACTIVE      0x0020
#define FLAGS_THROTTLED           0x0010
#define CLEAR_HALT_REQUIRED       0x0001

#define FLAGS_QUEUING             0x0100
#define FLAGS_APP_RESP_SEEN       0x0200
#define FLAGS_APP_REQ_SEEN        0x0400
#define FLAGS_DROP_DATA           0x0800

#define FLAGS_GSP_SKIP            0x1000
#define FLAGS_GSP_DLESEEN         0x2000






/* function prototypes */
static void gsp_next_packet(struct garmin_data * garmin_data_p);
static int  garmin_write_bulk(struct usb_serial_port *port,
			     const unsigned char *buf, int count);

/* some special packets to be send or received */
static unsigned char const GARMIN_START_SESSION_REQ[]
	= { 0, 0, 0, 0,  5, 0, 0, 0, 0, 0, 0, 0 };
static unsigned char const GARMIN_START_SESSION_REQ2[]
	= { 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0 };
static unsigned char const GARMIN_START_SESSION_REPLY[]
	= { 0, 0, 0, 0,  6, 0, 0, 0, 4, 0, 0, 0 };
static unsigned char const GARMIN_SESSION_ACTIVE_REPLY[]
	= { 0, 0, 0, 0, 17, 0, 0, 0, 4, 0, 0, 0, 0, 16, 0, 0 };
static unsigned char const GARMIN_BULK_IN_AVAIL_REPLY[]
	= { 0, 0, 0, 0,  2, 0, 0, 0, 0, 0, 0, 0 };
static unsigned char const GARMIN_APP_LAYER_REPLY[]
	= { 0x14, 0, 0, 0 };
static unsigned char const GARMIN_START_PVT_REQ[]
	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 49, 0 };
static unsigned char const GARMIN_STOP_PVT_REQ[]
	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 50, 0 };
static unsigned char const GARMIN_STOP_TRANSFER_REQ[]
	= { 20, 0, 0, 0,  10, 0, 0, 0, 2, 0, 0, 0, 0, 0 };
static unsigned char const GARMIN_STOP_TRANSFER_REQ_V2[]
	= { 20, 0, 0, 0,  10, 0, 0, 0, 1, 0, 0, 0, 0 };
static unsigned char const PRIVATE_REQ[]
	=    { 0x4B, 0x6E, 0x10, 0x01,  0xFF, 0, 0, 0, 0xFF, 0, 0, 0 };



static struct usb_device_id id_table [] = {
	/* the same device id seems to be used by all usb enabled gps devices */
	{ USB_DEVICE(GARMIN_VENDOR_ID, 3 ) },
	{ }					/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, id_table);

static struct usb_driver garmin_driver = {
	.name =		"garmin_gps",
	.probe =	usb_serial_probe,
	.disconnect =	usb_serial_disconnect,
	.id_table =	id_table,
	.no_dynamic_id = 	1,
};


static inline int noResponseFromAppLayer(struct garmin_data * garmin_data_p)
{
	return ((garmin_data_p->flags
				& (FLAGS_APP_REQ_SEEN|FLAGS_APP_RESP_SEEN))
	        == FLAGS_APP_REQ_SEEN);
}


static inline int getLayerId(const __u8 *usbPacket)
{
	return __le32_to_cpup((__le32 *)(usbPacket));
}

static inline int getPacketId(const __u8 *usbPacket)
{
	return __le32_to_cpup((__le32 *)(usbPacket+4));
}

static inline int getDataLength(const __u8 *usbPacket)
{
	return __le32_to_cpup((__le32 *)(usbPacket+8));
}


/*
 * check if the usb-packet in buf contains an abort-transfer command.
 * (if yes, all queued data will be dropped)
 */
static inline int isAbortTrfCmnd(const unsigned char *buf)
{
	if (0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ, 
	                sizeof(GARMIN_STOP_TRANSFER_REQ)) ||
	    0 == memcmp(buf, GARMIN_STOP_TRANSFER_REQ_V2, 
	                sizeof(GARMIN_STOP_TRANSFER_REQ_V2)))
		return 1;
	else
		return 0;
}



static void send_to_tty(struct usb_serial_port *port,
                        char *data, unsigned int actual_length)
{
	struct tty_struct *tty = port->tty;

	if (tty && actual_length) {

		usb_serial_debug_data(debug, &port->dev, 
					__FUNCTION__, actual_length, data);

		tty_buffer_request_room(tty, actual_length);
		tty_insert_flip_string(tty, data, actual_length);
		tty_flip_buffer_push(tty);
	}
}


/******************************************************************************
 * packet queue handling
 ******************************************************************************/

/*
 * queue a received (usb-)packet for later processing
 */
static int pkt_add(struct garmin_data * garmin_data_p,
                   unsigned char *data, unsigned int data_length)
{
	int result = 0;
	unsigned long flags;
	struct garmin_packet *pkt;

	/* process only packets containg data ... */
	if (data_length) {
		garmin_data_p->flags |= FLAGS_QUEUING;
		pkt = kmalloc(sizeof(struct garmin_packet)+data_length,
		              GFP_ATOMIC);
		if (pkt == NULL) {
			dev_err(&garmin_data_p->port->dev, "out of memory\n");
			return 0;
		}
		pkt->size = data_length;
		memcpy(pkt->data, data, data_length);

		spin_lock_irqsave(&garmin_data_p->lock, flags);
		result = list_empty(&garmin_data_p->pktlist);
		pkt->seq = garmin_data_p->seq_counter++;
		list_add_tail(&pkt->list, &garmin_data_p->pktlist);
		spin_unlock_irqrestore(&garmin_data_p->lock, flags);

		/* in serial mode, if someone is waiting for data from
		   the device, iconvert and send the next packet to tty. */
		if (result && (garmin_data_p->state == STATE_GSP_WAIT_DATA)) {
			gsp_next_packet(garmin_data_p);
		}
	}
	return result;
}


/* get the next pending packet */
static struct garmin_packet *pkt_pop(struct garmin_data * garmin_data_p)
{
	unsigned long flags;
	struct garmin_packet *result = NULL;

	spin_lock_irqsave(&garmin_data_p->lock, flags);
	if (!list_empty(&garmin_data_p->pktlist)) {
		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
		list_del(&result->list);
	}
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
	return result;
}


/* free up all queued data */
static void pkt_clear(struct garmin_data * garmin_data_p)
{
	unsigned long flags;
	struct garmin_packet *result = NULL;

	dbg("%s", __FUNCTION__);

	spin_lock_irqsave(&garmin_data_p->lock, flags);
	while (!list_empty(&garmin_data_p->pktlist)) {
		result = (struct garmin_packet *)garmin_data_p->pktlist.next;
		list_del(&result->list);
		kfree(result);
	}
	spin_unlock_irqrestore(&garmin_data_p->lock, flags);
}


/******************************************************************************
 * garmin serial protocol handling handling
 ******************************************************************************/

/* send an ack packet back to the tty */
static int gsp_send_ack(struct garmin_data * garmin_data_p, __u8 pkt_id)
{
	__u8 pkt[10];
        __u8 cksum = 0;
        __u8 *ptr = pkt;
        unsigned  l = 0;

	dbg("%s - pkt-id: 0x%X.", __FUNCTION__, 0xFF & pkt_id);

	*ptr++ = DLE;
	*ptr++ = ACK;
	cksum += ACK;

	*ptr++ = 2;
	cksum += 2;

	*ptr++ = pkt_id;
	cksum += pkt_id;

	if (pkt_id == DLE) {
		*ptr++ = DLE;
	}

	*ptr++ = 0;
	*ptr++ = 0xFF & (-cksum);
	*ptr++ = DLE;
	*ptr++ = ETX;

	l = ptr-pkt;

	send_to_tty(garmin_data_p->port, pkt, l);
	return 0;
}



/*
 * called for a complete packet received from tty layer
 *
 * the complete packet (pkzid ... cksum) is in garmin_data_p->inbuf starting
 * at GSP_INITIAL_OFFSET.
 *
 * count - number of bytes in the input buffer including space reserved for
 *         the usb header: GSP_INITIAL_OFFSET + number of bytes in packet 
 *         (including pkt-id, data-length a. cksum)
 */
static int gsp_rec_packet(struct garmin_data * garmin_data_p, int count)
{
	const __u8* recpkt = garmin_data_p->inbuffer+GSP_INITIAL_OFFSET;
        __le32 *usbdata = (__le32 *) garmin_data_p->inbuffer;

	int cksum = 0;
	int n = 0;
	int pktid = recpkt[0];
	int size = recpkt[1];

	usb_serial_debug_data(debug, &garmin_data_p->port->dev,
			       __FUNCTION__, count-GSP_INITIAL_OFFSET, recpkt);

	if (size != (count-GSP_INITIAL_OFFSET-3)) {
		dbg("%s - invalid size, expected %d bytes, got %d",
			__FUNCTION__, size, (count-GSP_INITIAL_OFFSET-3));
		return -EINVPKT;
	}

	cksum += *recpkt++;
	cksum += *recpkt++;

	// sanity check, remove after test ...
	if ((__u8*)&(usbdata[3]) != recpkt) {
		dbg("%s - ptr mismatch %p - %p",
			__FUNCTION__, &(usbdata[4]), recpkt);
		return -EINVPKT;
	}

	while (n < size) {
		cksum += *recpkt++;
		n++;
	}

       if ((0xff & (cksum + *recpkt)) != 0) {
                dbg("%s - invalid checksum, expected %02x, got %02x",
                        __FUNCTION__, 0xff & -cksum, 0xff & *recpkt);
                return -EINVPKT;
        }

	usbdata[0] = __cpu_to_le32(GARMIN_LAYERID_APPL);
	usbdata[1] = __cpu_to_le32(pktid);
	usbdata[2] = __cpu_to_le32(size);

	garmin_write_bulk (garmin_data_p->port, garmin_data_p->inbuffer,
			   GARMIN_PKTHDR_LENGTH+size);

	/* if this was an abort-transfer command, flush all
	   queued data. */
	if (isAbortTrfCmnd(garmin_data_p->inbuffer)) {
		garmin_data_p->flags |= FLAGS_DROP_DATA;
		pkt_clear(garmin_data_p);
	}

	return count;
}



/*
 * Called for data received from tty
 *
 * buf contains the data read, it may span more than one packet or even
 * incomplete packets
 *
 * input record should be a serial-record, but it may not be complete.
 * Copy it into our local buffer, until an etx is seen (or an error
 * occurs).
 * Once the record is complete, convert into a usb packet and send it
 * to the bulk pipe, send an ack back to the tty.
 *
 * If the input is an ack, just send the last queued packet to the
 * tty layer.
 *
 * if the input is an abort command, drop all queued data.
 */

static int gsp_receive(struct garmin_data * garmin_data_p,
                       const unsigned char *buf, int count)
{
	int offs = 0;
	int ack_or_nak_seen = 0;
	int i = 0;
	__u8 *dest = garmin_data_p->inbuffer;
	int size = garmin_data_p->insize;
	// dleSeen: set if last byte read was a DLE
	int dleSeen = garmin_data_p->flags & FLAGS_GSP_DLESEEN;
	// skip: if set, skip incoming data until possible start of
	//       new packet
	int skip = garmin_data_p->flags & FLAGS_GSP_SKIP;
	__u8 data;

	dbg("%s - dle=%d skip=%d size=%d count=%d",