cpia_pp.c

一个2.4.21版本的嵌入式linux内核

/*
 * cpia_pp CPiA Parallel Port driver
 *
 * Supports CPiA based parallel port Video Camera's.
 *
 * (C) Copyright 1999 Bas Huisman <[e-mail]>
 * (C) Copyright 1999-2000 Scott J. Bertin <[e-mail]>,
 * (C) Copyright 1999-2000 Peter Pregler <[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.
 */

/* define _CPIA_DEBUG_ for verbose debug output (see cpia.h) */
/* #define _CPIA_DEBUG_  1 */  

#include <linux/config.h>
#include <linux/version.h>

#include <linux/module.h>
#include <linux/init.h>

#include <linux/kernel.h>
#include <linux/parport.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/smp_lock.h>
#include <linux/sched.h>

#include <linux/kmod.h>

/* #define _CPIA_DEBUG_		define for verbose debug output */
#include "cpia.h"

static int cpia_pp_open(void *privdata);
static int cpia_pp_registerCallback(void *privdata, void (*cb) (void *cbdata),
                                    void *cbdata);
static int cpia_pp_transferCmd(void *privdata, u8 *command, u8 *data);
static int cpia_pp_streamStart(void *privdata);
static int cpia_pp_streamStop(void *privdata);
static int cpia_pp_streamRead(void *privdata, u8 *buffer, int noblock);
static int cpia_pp_close(void *privdata);

#define ABOUT "Parallel port driver for Vision CPiA based cameras"

#define PACKET_LENGTH 	8

/* Magic numbers for defining port-device mappings */
#define PPCPIA_PARPORT_UNSPEC -4
#define PPCPIA_PARPORT_AUTO -3
#define PPCPIA_PARPORT_OFF -2
#define PPCPIA_PARPORT_NONE -1

#ifdef MODULE
static int parport_nr[PARPORT_MAX] = {[0 ... PARPORT_MAX - 1] = PPCPIA_PARPORT_UNSPEC};
static char *parport[PARPORT_MAX] = {NULL,};

MODULE_AUTHOR("B. Huisman <[e-mail]> & Peter Pregler <[e-mail]>");
MODULE_DESCRIPTION("Parallel port driver for Vision CPiA based cameras");
MODULE_LICENSE("GPL");

MODULE_PARM(parport, "1-" __MODULE_STRING(PARPORT_MAX) "s");
MODULE_PARM_DESC(parport, "'auto' or a list of parallel port numbers. Just like lp.");
#else
static int parport_nr[PARPORT_MAX] __initdata =
	{[0 ... PARPORT_MAX - 1] = PPCPIA_PARPORT_UNSPEC};
static int parport_ptr = 0;
#endif

struct pp_cam_entry {
	struct pardevice *pdev;
	struct parport *port;
	struct tq_struct cb_task;
	int open_count;
	wait_queue_head_t wq_stream;
	/* image state flags */
	int image_ready;	/* we got an interrupt */
	int image_complete;	/* we have seen 4 EOI */

	int streaming; /* we are in streaming mode */
	int stream_irq;
};

static struct cpia_camera_ops cpia_pp_ops = 
{
	cpia_pp_open,
	cpia_pp_registerCallback,
	cpia_pp_transferCmd,
	cpia_pp_streamStart,
	cpia_pp_streamStop,
	cpia_pp_streamRead,
	cpia_pp_close,
	1,
	THIS_MODULE
};

static LIST_HEAD(cam_list);
static spinlock_t cam_list_lock_pp;

/* FIXME */
static void cpia_parport_enable_irq( struct parport *port ) {
	parport_enable_irq(port);
	mdelay(10);
	return;
}

static void cpia_parport_disable_irq( struct parport *port ) {
	parport_disable_irq(port);
	mdelay(10);
	return;
}

/* Special CPiA PPC modes: These are invoked by using the 1284 Extensibility
 * Link Flag during negotiation */  
#define UPLOAD_FLAG  0x08
#define ECP_TRANSFER 0x03

#define PARPORT_CHUNK_SIZE	PAGE_SIZE


/****************************************************************************
 *
 *  EndTransferMode
 *
 ***************************************************************************/
static void EndTransferMode(struct pp_cam_entry *cam)
{
	parport_negotiate(cam->port, IEEE1284_MODE_COMPAT);
}

/****************************************************************************
 *
 *  ForwardSetup
 *
 ***************************************************************************/
static int ForwardSetup(struct pp_cam_entry *cam)
{
	int retry;
	
	/* After some commands the camera needs extra time before
	 * it will respond again, so we try up to 3 times */
	for(retry=0; retry<3; ++retry) {
		if(!parport_negotiate(cam->port, IEEE1284_MODE_ECP)) {
			break;
		}
	}
	if(retry == 3) {
		DBG("Unable to negotiate ECP mode\n");
		return -1;
	}
	return 0;
}

/****************************************************************************
 *
 *  ReverseSetup
 *
 ***************************************************************************/
static int ReverseSetup(struct pp_cam_entry *cam, int extensibility)
{
	int retry;
	int mode = IEEE1284_MODE_ECP;
	if(extensibility) mode = UPLOAD_FLAG|ECP_TRANSFER|IEEE1284_EXT_LINK;

	/* After some commands the camera needs extra time before
	 * it will respond again, so we try up to 3 times */
	for(retry=0; retry<3; ++retry) {
		if(!parport_negotiate(cam->port, mode)) {
			break;
		}
	}
	if(retry == 3) {
		if(extensibility)
			DBG("Unable to negotiate extensibility mode\n");
		else
			DBG("Unable to negotiate ECP mode\n");
		return -1;
	}
	if(extensibility) cam->port->ieee1284.mode = IEEE1284_MODE_ECP;
	return 0;
}

/****************************************************************************
 *
 *  WritePacket
 *
 ***************************************************************************/
static int WritePacket(struct pp_cam_entry *cam, const u8 *packet, size_t size)
{
	int retval=0;
	int size_written;

	if (packet == NULL) {
		return -EINVAL;
	}
	if (ForwardSetup(cam)) {
		DBG("Write failed in setup\n");
		return -EIO;
	}
	size_written = parport_write(cam->port, packet, size);
	if(size_written != size) {
		DBG("Write failed, wrote %d/%d\n", size_written, size);
		retval = -EIO;
	}
	EndTransferMode(cam);
	return retval;
}

/****************************************************************************
 *
 *  ReadPacket
 *
 ***************************************************************************/
static int ReadPacket(struct pp_cam_entry *cam, u8 *packet, size_t size)
{
	int retval=0;
	if (packet == NULL) {
		return -EINVAL;
	}
	if (ReverseSetup(cam, 0)) {
		return -EIO;
	}
	if(parport_read(cam->port, packet, size) != size) {
		retval = -EIO;
	}
	EndTransferMode(cam);
	return retval;
}

/****************************************************************************
 *
 *  cpia_pp_streamStart
 *
 ***************************************************************************/
static int cpia_pp_streamStart(void *privdata)
{
	struct pp_cam_entry *cam = privdata;
	DBG("\n");
	cam->streaming=1;
	cam->image_ready=0;
	//if (ReverseSetup(cam,1)) return -EIO;
	if(cam->stream_irq) cpia_parport_enable_irq(cam->port);
	return 0;
}

/****************************************************************************
 *
 *  cpia_pp_streamStop
 *
 ***************************************************************************/
static int cpia_pp_streamStop(void *privdata)
{
	struct pp_cam_entry *cam = privdata;

	DBG("\n");
	cam->streaming=0;
	cpia_parport_disable_irq(cam->port);
	//EndTransferMode(cam);

	return 0;
}

/****************************************************************************
 *
 *  cpia_pp_streamRead
 *
 ***************************************************************************/
static int cpia_pp_read(struct parport *port, u8 *buffer, int len)
{
	int bytes_read, new_bytes;
	for(bytes_read=0; bytes_read<len; bytes_read += new_bytes) {
		new_bytes = parport_read(port, buffer+bytes_read,
			                 len-bytes_read);
		if(new_bytes < 0) break;
	}
	return bytes_read;
}

static int cpia_pp_streamRead(void *privdata, u8 *buffer, int noblock)
{
	struct pp_cam_entry *cam = privdata;
	int read_bytes = 0;
	int i, endseen, block_size, new_bytes;

	if(cam == NULL) {
		DBG("Internal driver error: cam is NULL\n");
		return -EINVAL;
	}
	if(buffer == NULL) {
		DBG("Internal driver error: buffer is NULL\n");
		return -EINVAL;
	}
	//if(cam->streaming) DBG("%d / %d\n", cam->image_ready, noblock);
	if( cam->stream_irq ) {
		DBG("%d\n", cam->image_ready);
		cam->image_ready--;
	}
	cam->image_complete=0;
	if (0/*cam->streaming*/) {
		if(!cam->image_ready) {
			if(noblock) return -EWOULDBLOCK;
			interruptible_sleep_on(&cam->wq_stream);
			if( signal_pending(current) ) return -EINTR;
			DBG("%d\n", cam->image_ready);
		}
	} else {
		if (ReverseSetup(cam, 1)) {
			DBG("unable to ReverseSetup\n");
			return -EIO;
		}
	}
	endseen = 0;
	block_size = PARPORT_CHUNK_SIZE;
	while( !cam->image_complete ) {
		if(current->need_resched)  schedule();
		
		new_bytes = cpia_pp_read(cam->port, buffer, block_size );
		if( new_bytes <= 0 ) {
			break;
		}
		i=-1;
		while(++i<new_bytes && endseen<4) {
	        	if(*buffer==EOI) {
	                	endseen++;
	                } else {
	                	endseen=0;