lp.c

unix/linux 编程实践一书的所有源代码

					else
						return -EINTR;
				}

#ifdef LP_STATS
				lp->runchars = 0;
#endif

				if (lp_check_status(minor))
				{
					w_ctr(minor, LP_PSELECP | LP_PINITP);
					return rc ? rc : -EIO;
				}

				if (LP_POLLED(minor) ||
				    lp_table[minor].irq_missed)
				{
				lp_polling:
#if defined(LP_DEBUG) && defined(LP_STATS)
					printk(KERN_DEBUG "lp%d sleeping at %d characters for %d jiffies\n", minor, lp->runchars, LP_TIME(minor));
#endif
					current->state = TASK_INTERRUPTIBLE;
					lp_schedule(minor, LP_TIME(minor));
				} else {
					cli();
					if (LP_PREEMPTED(minor))
					{
						/*
						 * We can' t sleep on the interrupt
						 * since another pardevice need the port.
						 * We must check this in a cli() protected
						 * envinroment to avoid parport sharing
						 * starvation.
						 */
						sti();
						goto lp_polling;
					}
					if (!lp_table[minor].irq_detected)
						interruptible_sleep_on_timeout(&lp->wait_q, LP_TIMEOUT_INTERRUPT);
					sti();
				}
			}
		}

		total_bytes_written += bytes_written;
		buf += bytes_written;
		count -= bytes_written;

	} while (count > 0);

	w_ctr(minor, LP_PSELECP | LP_PINITP);
	return total_bytes_written;
}

static ssize_t lp_write(struct file * file, const char * buf,
		        size_t count, loff_t *ppos)
{
	unsigned int minor = MINOR(file->f_dentry->d_inode->i_rdev);
	ssize_t retv;

#ifdef LP_STATS
	if (jiffies-lp_table[minor].lastcall > LP_TIME(minor))
		lp_table[minor].runchars = 0;

	lp_table[minor].lastcall = jiffies;
#endif

 	/* Claim Parport or sleep until it becomes available
 	 */
 	lp_parport_claim (minor);

	retv = lp_write_buf(minor, buf, count);

 	lp_parport_release (minor);
 	return retv;
}

static long long lp_lseek(struct file * file, long long offset, int origin)
{
	return -ESPIPE;
}

#ifdef CONFIG_PRINTER_READBACK

static int lp_read_nibble(int minor) 
{
	unsigned char i;
	i = r_str(minor)>>3;
	i &= ~8;
	if ((i & 0x10) == 0) i |= 8;
	return (i & 0x0f);
}

static void lp_read_terminate(struct parport *port) {
	parport_write_control(port, (parport_read_control(port) & ~2) | 8);
	/* SelectIN high, AutoFeed low */
	if (parport_wait_peripheral(port, 0x80, 0)) 
		/* timeout, SelectIN high, Autofeed low */
		return;
	parport_write_control(port, parport_read_control(port) | 2);
	/* AutoFeed high */
	parport_wait_peripheral(port, 0x80, 0x80);
	/* no timeout possible, Autofeed low, SelectIN high */
	parport_write_control(port, (parport_read_control(port) & ~2) | 8);
}

/* Status readback confirming to ieee1284 */
static ssize_t lp_read(struct file * file, char * buf,
		       size_t length, loff_t *ppos)
{
	int i;
	unsigned int minor=MINOR(file->f_dentry->d_inode->i_rdev);
	char *temp = buf;
	ssize_t count = 0;
	unsigned char z = 0;
	unsigned char Byte = 0;
	struct parport *port = lp_table[minor].dev->port;

	lp_parport_claim (minor);

	switch (parport_ieee1284_nibble_mode_ok(port, 0))
	{
	case 0:
		/* Handshake failed. */
		lp_read_terminate(port);
		lp_parport_release (minor);
		return -EIO;
	case 1:
		/* No data. */
		lp_read_terminate(port);
		lp_parport_release (minor);
		return 0;
	default:
		/* Data available. */

		/* Hack: Wait 10ms (between events 6 and 7) */
		current->state = TASK_INTERRUPTIBLE;
                schedule_timeout((HZ+99)/100);
                break;
	}

	for (i=0; ; i++) {
		parport_frob_control(port, 2, 2); /* AutoFeed high */
		if (parport_wait_peripheral(port, 0x40, 0)) {
#ifdef LP_READ_DEBUG
			/* Some peripherals just time out when they've sent
			   all their data.  */
			printk("%s: read1 timeout.\n", port->name);
#endif
			parport_frob_control(port, 2, 0); /* AutoFeed low */
			break;
		}
		z = lp_read_nibble(minor);
		parport_frob_control(port, 2, 0); /* AutoFeed low */
		if (parport_wait_peripheral(port, 0x40, 0x40)) {
			printk("%s: read2 timeout.\n", port->name);
			break;
		}
		if ((i & 1) != 0) {
			Byte |= (z<<4);
			if (__put_user (Byte, temp))
			{
				count = -EFAULT;
				break;
			} else {
				temp++;

				if (++count == length)
					break;
			}
			/* Does the error line indicate end of data? */
			if ((parport_read_status(port) & LP_PERRORP) == 
			    LP_PERRORP) 
				break;
		} else 
			Byte=z;
	}

	lp_read_terminate(port);

	lp_parport_release (minor);

	return count;
}

#endif

static int lp_open(struct inode * inode, struct file * file)
{
	unsigned int minor = MINOR(inode->i_rdev);

	if (minor >= LP_NO)
		return -ENXIO;
	if ((LP_F(minor) & LP_EXIST) == 0)
		return -ENXIO;
	if (test_and_set_bit(LP_BUSY_BIT_POS, &LP_F(minor)))
		return -EBUSY;

	MOD_INC_USE_COUNT;

	/* If ABORTOPEN is set and the printer is offline or out of paper,
	   we may still want to open it to perform ioctl()s.  Therefore we
	   have commandeered O_NONBLOCK, even though it is being used in
	   a non-standard manner.  This is strictly a Linux hack, and
	   should most likely only ever be used by the tunelp application. */
	if ((LP_F(minor) & LP_ABORTOPEN) && !(file->f_flags & O_NONBLOCK)) {
		int status;
		lp_parport_claim (minor);
		status = r_str(minor);
		lp_parport_release (minor);
		if (status & LP_POUTPA) {
			printk(KERN_INFO "lp%d out of paper\n", minor);
			MOD_DEC_USE_COUNT;
			LP_F(minor) &= ~LP_BUSY;
			return -ENOSPC;
		} else if (!(status & LP_PSELECD)) {
			printk(KERN_INFO "lp%d off-line\n", minor);
			MOD_DEC_USE_COUNT;
			LP_F(minor) &= ~LP_BUSY;
			return -EIO;
		} else if (!(status & LP_PERRORP)) {
			printk(KERN_ERR "lp%d printer error\n", minor);
			MOD_DEC_USE_COUNT;
			LP_F(minor) &= ~LP_BUSY;
			return -EIO;
		}
	}
	lp_table[minor].lp_buffer = (char *) kmalloc(LP_BUFFER_SIZE, GFP_KERNEL);
	if (!lp_table[minor].lp_buffer) {
		MOD_DEC_USE_COUNT;
		LP_F(minor) &= ~LP_BUSY;
		return -ENOMEM;
	}
	return 0;
}

static int lp_release(struct inode * inode, struct file * file)
{
	unsigned int minor = MINOR(inode->i_rdev);

	kfree_s(lp_table[minor].lp_buffer, LP_BUFFER_SIZE);
	lp_table[minor].lp_buffer = NULL;
	MOD_DEC_USE_COUNT;
	LP_F(minor) &= ~LP_BUSY;
	return 0;
}

static int lp_ioctl(struct inode *inode, struct file *file,
		    unsigned int cmd, unsigned long arg)
{
	unsigned int minor = MINOR(inode->i_rdev);
	int status;
	int retval = 0;

#ifdef LP_DEBUG
	printk(KERN_DEBUG "lp%d ioctl, cmd: 0x%x, arg: 0x%x\n", minor, cmd, arg);
#endif
	if (minor >= LP_NO)
		return -ENODEV;
	if ((LP_F(minor) & LP_EXIST) == 0)
		return -ENODEV;
	switch ( cmd ) {
		case LPTIME:
			LP_TIME(minor) = arg * HZ/100;
			break;
		case LPCHAR:
			LP_CHAR(minor) = arg;
			break;
		case LPABORT:
			if (arg)
				LP_F(minor) |= LP_ABORT;
			else
				LP_F(minor) &= ~LP_ABORT;
			break;
		case LPABORTOPEN:
			if (arg)
				LP_F(minor) |= LP_ABORTOPEN;
			else
				LP_F(minor) &= ~LP_ABORTOPEN;
			break;
		case LPCAREFUL:
			if (arg)
				LP_F(minor) |= LP_CAREFUL;
			else
				LP_F(minor) &= ~LP_CAREFUL;
			break;
		case LPTRUSTIRQ:
			if (arg)
				LP_F(minor) |= LP_TRUST_IRQ;
			else
				LP_F(minor) &= ~LP_TRUST_IRQ;
			break;
		case LPWAIT:
			LP_WAIT(minor) = arg;
			break;
		case LPSETIRQ: 
			return -EINVAL;
			break;
		case LPGETIRQ:
			if (copy_to_user((int *) arg, &LP_IRQ(minor),
					sizeof(int)))
				return -EFAULT;
			break;
		case LPGETSTATUS:
			lp_parport_claim(minor);
			status = r_str(minor);
			lp_parport_release(minor);

			if (copy_to_user((int *) arg, &status, sizeof(int)))
				return -EFAULT;
			break;
		case LPRESET:
			lp_reset(minor);
			break;
#ifdef LP_STATS
		case LPGETSTATS:
			if (copy_to_user((int *) arg, &LP_STAT(minor),
					sizeof(struct lp_stats)))
				return -EFAULT;
			if (suser())
				memset(&LP_STAT(minor), 0,
						sizeof(struct lp_stats));
			break;
#endif
 		case LPGETFLAGS:
 			status = LP_F(minor);
			if (copy_to_user((int *) arg, &status, sizeof(int)))
				return -EFAULT;
			break;
		default:
			retval = -EINVAL;
	}
	return retval;
}

static struct file_operations lp_fops = {
	lp_lseek,
#ifdef CONFIG_PRINTER_READBACK
	lp_read,
#else
	NULL,
#endif
	lp_write,
	NULL,		/* lp_readdir */
	NULL,		/* lp_poll */
	lp_ioctl,
	NULL,		/* lp_mmap */
	lp_open,
	NULL,		/* flush */
	lp_release
};

/* --- initialisation code ------------------------------------- */

#ifdef MODULE

static int parport_nr[LP_NO] = { [0 ... LP_NO-1] = LP_PARPORT_UNSPEC };
static char *parport[LP_NO] = { NULL,  };
static int reset = 0;

MODULE_PARM(parport, "1-" __MODULE_STRING(LP_NO) "s");
MODULE_PARM(reset, "i");

#else

static int parport_nr[LP_NO] __initdata = { [0 ... LP_NO-1] = LP_PARPORT_UNSPEC };
static int reset __initdata = 0;

static int parport_ptr = 0;

__initfunc(void lp_setup(char *str, int *ints))
{
	if (!str) {
		if (ints[0] == 0 || ints[1] == 0) {
			/* disable driver on "lp=" or "lp=0" */
			parport_nr[0] = LP_PARPORT_OFF;
		} else {
			printk(KERN_WARNING "warning: 'lp=0x%x' is deprecated, ignored\n", ints[1]);
		}
	} else if (!strncmp(str, "parport", 7)) {
		int n = simple_strtoul(str+7, NULL, 10);
		if (parport_ptr < LP_NO)
			parport_nr[parport_ptr++] = n;
		else
			printk(KERN_INFO "lp: too many ports, %s ignored.\n",
			       str);
	} else if (!strcmp(str, "auto")) {
		parport_nr[0] = LP_PARPORT_AUTO;
	} else if (!strcmp(str, "none")) {
		parport_nr[parport_ptr++] = LP_PARPORT_NONE;
	} else if (!strcmp(str, "reset")) {
		reset = 1;
	}
}

#endif

int lp_register(int nr, struct parport *port)
{
	lp_table[nr].dev = parport_register_device(port, "lp", 
						   lp_preempt, NULL,
						   lp_interrupt, 
						   0,
						   (void *) &lp_table[nr]);
	if (lp_table[nr].dev == NULL)
		return 1;
	lp_table[nr].flags |= LP_EXIST;

	if (reset)
		lp_reset(nr);

	printk(KERN_INFO "lp%d: using %s (%s).\n", nr, port->name, 
	       (port->irq == PARPORT_IRQ_NONE)?"polling":"interrupt-driven");

	return 0;
}

int lp_init(void)
{
	unsigned int count = 0;
	unsigned int i;
	struct parport *port;

	switch (parport_nr[0])
	{
	case LP_PARPORT_OFF:
		return 0;

	case LP_PARPORT_UNSPEC:
	case LP_PARPORT_AUTO:
	        for (port = parport_enumerate(); port; port = port->next) {

			if (parport_nr[0] == LP_PARPORT_AUTO &&
			    port->probe_info.class != PARPORT_CLASS_PRINTER)
				continue;

			if (!lp_register(count, port))
				if (++count == LP_NO)
					break;
		}
		break;

	default:
		for (i = 0; i < LP_NO; i++) {
			for (port = parport_enumerate(); port; 
			     port = port->next) {
				if (port->number == parport_nr[i]) {
					if (!lp_register(i, port))
						count++;
					break;
				}
			}
		}
		break;
	}

	if (count) {
		if (register_chrdev(LP_MAJOR, "lp", &lp_fops)) {
			printk("lp: unable to get major %d\n", LP_MAJOR);
			return -EIO;
		}
	} else {
		printk(KERN_INFO "lp: no devices found\n");
		return -ENODEV;
	}

	return 0;
}

#ifdef MODULE
int init_module(void)
{
	if (parport[0]) {
		/* The user gave some parameters.  Let's see what they were.  */
		if (!strncmp(parport[0], "auto", 4))
			parport_nr[0] = LP_PARPORT_AUTO;
		else {
			int n;
			for (n = 0; n < LP_NO && parport[n]; n++) {
				if (!strncmp(parport[n], "none", 4))
					parport_nr[n] = LP_PARPORT_NONE;
				else {
					char *ep;
					unsigned long r = simple_strtoul(parport[n], &ep, 0);
					if (ep != parport[n]) 
						parport_nr[n] = r;
					else {
						printk(KERN_ERR "lp: bad port specifier `%s'\n", parport[n]);
						return -ENODEV;
					}
				}
			}
		}
	}

	return lp_init();
}

void cleanup_module(void)
{
	unsigned int offset;

	unregister_chrdev(LP_MAJOR, "lp");
	for (offset = 0; offset < LP_NO; offset++) {
		if (lp_table[offset].dev == NULL)
			continue;
		parport_unregister_device(lp_table[offset].dev);
	}
}
#endif