c-qcam.c

powerpc内核mpc8241linux系统下char驱动程序

/*
 *	Video4Linux Colour QuickCam driver
 *	Copyright 1997-1998 Philip Blundell <[e-mail]>
 *
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/malloc.h>
#include <linux/mm.h>
#include <linux/parport.h>
#include <linux/sched.h>
#include <linux/version.h>
#include <linux/videodev.h>
#include <asm/uaccess.h>

struct qcam_device {
	struct video_device vdev;
	struct pardevice *pdev;
	struct parport *pport;
	int width, height;
	int ccd_width, ccd_height;
	int mode;
	int contrast, brightness, whitebal;
	int top, left;
	unsigned int bidirectional;
};

/* The three possible QuickCam modes */
#define QC_MILLIONS	0x18
#define QC_BILLIONS	0x10
#define QC_THOUSANDS	0x08	/* with VIDEC compression (not supported) */

/* The three possible decimations */
#define QC_DECIMATION_1		0
#define QC_DECIMATION_2		2
#define QC_DECIMATION_4		4

static inline void qcam_set_ack(struct qcam_device *qcam, unsigned int i)
{
	/* note: the QC specs refer to the PCAck pin by voltage, not
	   software level.  PC ports have builtin inverters. */
	parport_frob_control(qcam->pport, 8, i?8:0);
}

static inline unsigned int qcam_ready1(struct qcam_device *qcam)
{
	return (parport_read_status(qcam->pport) & 0x8)?1:0;
}

static inline unsigned int qcam_ready2(struct qcam_device *qcam)
{
	return (parport_read_data(qcam->pport) & 0x1)?1:0;
}

static unsigned int qcam_await_ready1(struct qcam_device *qcam, 
					     int value)
{
	unsigned long oldjiffies = jiffies;
	unsigned int i;

	for (oldjiffies = jiffies; (jiffies - oldjiffies) < (HZ/25); )
		if (qcam_ready1(qcam) == value)
			return 0;

	/* If the camera didn't respond within 1/25 second, poll slowly 
	   for a while. */
	for (i = 0; i < 50; i++)
	{
		if (qcam_ready1(qcam) == value)
			return 0;
		current->state=TASK_INTERRUPTIBLE;
		schedule_timeout(HZ/10);
	}

	/* Probably somebody pulled the plug out.  Not much we can do. */
	printk(KERN_ERR "c-qcam: ready1 timeout (%d) %x %x\n", value,
	       parport_read_status(qcam->pport),
	       parport_read_control(qcam->pport));
	return 1;
}

static unsigned int qcam_await_ready2(struct qcam_device *qcam, int value)
{
	unsigned long oldjiffies = jiffies;
	unsigned int i;

	for (oldjiffies = jiffies; (jiffies - oldjiffies) < (HZ/25); )
		if (qcam_ready2(qcam) == value)
			return 0;

	/* If the camera didn't respond within 1/25 second, poll slowly 
	   for a while. */
	for (i = 0; i < 50; i++)
	{
		if (qcam_ready2(qcam) == value)
			return 0;
		current->state=TASK_INTERRUPTIBLE;
		schedule_timeout(HZ/10);
	}

	/* Probably somebody pulled the plug out.  Not much we can do. */
	printk(KERN_ERR "c-qcam: ready2 timeout (%d) %x %x %x\n", value,
	       parport_read_status(qcam->pport),
	       parport_read_control(qcam->pport),
	       parport_read_data(qcam->pport));
	return 1;
}

static int qcam_read_data(struct qcam_device *qcam)
{
	unsigned int idata;
	qcam_set_ack(qcam, 0);
	if (qcam_await_ready1(qcam, 1)) return -1;
	idata = parport_read_status(qcam->pport) & 0xf0;
	qcam_set_ack(qcam, 1);
	if (qcam_await_ready1(qcam, 0)) return -1;
	idata |= (parport_read_status(qcam->pport) >> 4);
	return idata;
}

static int qcam_write_data(struct qcam_device *qcam, unsigned int data)
{
	unsigned int idata;
	parport_write_data(qcam->pport, data);
	idata = qcam_read_data(qcam);
	if (data != idata) 
	{
		printk(KERN_WARNING "cqcam: sent %x but received %x\n", data, 
		       idata);
		return 1;
	} 
	return 0;
}

static inline int qcam_set(struct qcam_device *qcam, unsigned int cmd, unsigned int data)
{
	if (qcam_write_data(qcam, cmd))
		return -1;
	if (qcam_write_data(qcam, data))
		return -1;
	return 0;
}

static inline int qcam_get(struct qcam_device *qcam, unsigned int cmd)
{
	if (qcam_write_data(qcam, cmd))
		return -1;
	return qcam_read_data(qcam);
}

static int qc_detect(struct qcam_device *qcam)
{
	unsigned int stat, ostat, i, count = 0;

	parport_write_control(qcam->pport, 0xc);

	/* look for a heartbeat */
	ostat = stat = parport_read_status(qcam->pport);
	for (i=0; i<250; i++) 
	{
		mdelay(1);
		stat = parport_read_status(qcam->pport);
		if (ostat != stat) 
		{
			if (++count >= 3) return 1;
			ostat = stat;
		}
	}

	/* no (or flatline) camera, give up */
	return 0;
}

static void qc_reset(struct qcam_device *qcam)
{
	parport_write_control(qcam->pport, 0xc);
	parport_write_control(qcam->pport, 0x8);
	mdelay(1);
	parport_write_control(qcam->pport, 0xc);
	mdelay(1);          
}

/* Reset the QuickCam and program for brightness, contrast,
 * white-balance, and resolution. */

static void qc_setup(struct qcam_device *q)
{
	qc_reset(q);

	/* Set the brightness.  */
       	qcam_set(q, 11, q->brightness);

	/* Set the height and width.  These refer to the actual
	   CCD area *before* applying the selected decimation.  */
	qcam_set(q, 17, q->ccd_height);
	qcam_set(q, 19, q->ccd_width / 2);

	/* Set top and left.  */
	qcam_set(q, 0xd, q->top);
	qcam_set(q, 0xf, q->left);

	/* Set contrast and white balance.  */
	qcam_set(q, 0x19, q->contrast);
	qcam_set(q, 0x1f, q->whitebal);
	
	/* Set the speed.  */
	qcam_set(q, 45, 2);
}

/* Read some bytes from the camera and put them in the buffer. 
   nbytes should be a multiple of 3, because bidirectional mode gives
   us three bytes at a time.  */

static unsigned int qcam_read_bytes(struct qcam_device *q, unsigned char *buf, unsigned int nbytes)
{
	unsigned int bytes = 0;
	qcam_set_ack(q, 0);
	if (q->bidirectional)
	{
		/* It's a bidirectional port */
		while (bytes < nbytes)
		{
			unsigned int lo1, hi1, lo2, hi2;
			if (qcam_await_ready2(q, 1)) return bytes;
			lo1 = parport_read_data(q->pport) >> 1;
			hi1 = ((parport_read_status(q->pport) >> 3) & 0x1f) ^ 0x10;
			qcam_set_ack(q, 1);
			if (qcam_await_ready2(q, 0)) return bytes;
			lo2 = parport_read_data(q->pport) >> 1;
			hi2 = ((parport_read_status(q->pport) >> 3) & 0x1f) ^ 0x10;
			qcam_set_ack(q, 0);
			buf[bytes++] = (lo1 | ((hi1 & 1)<<7));
			buf[bytes++] = ((hi1 & 0x1e)<<3) | ((hi2 & 0x1e)>>1);
			buf[bytes++] = (lo2 | ((hi2 & 1)<<7));
		}
	}
	else
	{
		/* It's a unidirectional port */
		while (bytes < nbytes)
		{
			unsigned int hi, lo;
			if (qcam_await_ready1(q, 1)) return bytes;
			hi = (parport_read_status(q->pport) & 0xf0);
			qcam_set_ack(q, 1);
			if (qcam_await_ready1(q, 0)) return bytes;
			lo = (parport_read_status(q->pport) & 0xf0);
			qcam_set_ack(q, 0);
			/* flip some bits */
			buf[bytes++] = (hi | (lo >> 4)) ^ 0x88;
		}
	}
	return bytes;
}

#define BUFSZ	150

static long qc_capture(struct qcam_device *q, char *buf, unsigned long len)
{
	unsigned lines, pixelsperline, bitsperxfer;
	unsigned int is_bi_dir = q->bidirectional;
	size_t wantlen, outptr = 0;
	char tmpbuf[BUFSZ];

	if (verify_area(VERIFY_WRITE, buf, len))
		return -EFAULT;

	/* Wait for camera to become ready */
	for (;;)
	{
		int i = qcam_get(q, 41);
		if (i == -1) {
			qc_setup(q);
			return -EIO;
		}
		if ((i & 0x80) == 0)
			break;
		else
			schedule();
	}

	if (qcam_set(q, 7, (q->mode | (is_bi_dir?1:0)) + 1))
		return -EIO;
	
	lines = q->height;
	pixelsperline = q->width;
	bitsperxfer = (is_bi_dir) ? 24 : 8;

	if (is_bi_dir)
	{
		/* Turn the port around */
		parport_frob_control(q->pport, 0x20, 0x20);
		mdelay(3);
		qcam_set_ack(q, 0);
		if (qcam_await_ready1(q, 1)) {
			qc_setup(q);
			return -EIO;
		}
		qcam_set_ack(q, 1);
		if (qcam_await_ready1(q, 0)) {
			qc_setup(q);
			return -EIO;
		}
	}

	wantlen = lines * pixelsperline * 24 / 8;

	while (wantlen)
	{
		size_t t, s;
		s = (wantlen > BUFSZ)?BUFSZ:wantlen;
		t = qcam_read_bytes(q, tmpbuf, s);
		if (outptr < len)
		{
			size_t sz = len - outptr;
			if (sz > t) sz = t;
			if (__copy_to_user(buf+outptr, tmpbuf, sz))
				break;
			outptr += sz;
		}
		wantlen -= t;
		if (t < s)
			break;
		if (current->need_resched)
			schedule();
	}

	len = outptr;

	if (wantlen)
	{
		printk("qcam: short read.\n");
		if (is_bi_dir)
			parport_frob_control(q->pport, 0x20, 0);
		qc_setup(q);
		return len;
	}

	if (is_bi_dir)
	{
		int l;
		do {
			l = qcam_read_bytes(q, tmpbuf, 3);
			if (current->need_resched)
				schedule();
		} while (l && (tmpbuf[0] == 0x7e || tmpbuf[1] == 0x7e || tmpbuf[2] == 0x7e));
		if (tmpbuf[0] != 0xe || tmpbuf[1] != 0x0 || tmpbuf[2] != 0xf)
			printk("qcam: bad EOF\n");
		qcam_set_ack(q, 0);
		if (qcam_await_ready1(q, 1))
		{
			printk("qcam: no ack after EOF\n");
			parport_frob_control(q->pport, 0x20, 0);
			qc_setup(q);
			return len;
		}
		parport_frob_control(q->pport, 0x20, 0);
		mdelay(3);
		qcam_set_ack(q, 1);
		if (qcam_await_ready1(q, 0))
		{
			printk("qcam: no ack to port turnaround\n");
			qc_setup(q);
			return len;
		}
	}
	else
	{
		int l;
		do {
			l = qcam_read_bytes(q, tmpbuf, 1);
			if (current->need_resched)
				schedule();
		} while (l && tmpbuf[0] == 0x7e);
		l = qcam_read_bytes(q, tmpbuf+1, 2);
		if (tmpbuf[0] != 0xe || tmpbuf[1] != 0x0 || tmpbuf[2] != 0xf)