cdc-acm.c

linux qt class 类的函数定义

/*
 * acm.c  Version 0.21
 *
 * Copyright (c) 1999 Armin Fuerst	<[e-mail]>
 * Copyright (c) 1999 Pavel Machek	<[e-mail]>
 * Copyright (c) 1999 Johannes Erdfelt	<[e-mail]>
 * Copyright (c) 2000 Vojtech Pavlik	<[e-mail]>
 *
 * USB Abstract Control Model driver for USB modems and ISDN adapters
 *
 * Sponsored by SuSE
 *
 * ChangeLog:
 *	v0.9  - thorough cleaning, URBification, almost a rewrite
 *	v0.10 - some more cleanups
 *	v0.11 - fixed flow control, read error doesn't stop reads
 *	v0.12 - added TIOCM ioctls, added break handling, made struct acm kmalloced
 *	v0.13 - added termios, added hangup
 *	v0.14 - sized down struct acm
 *	v0.15 - fixed flow control again - characters could be lost
 *	v0.16 - added code for modems with swapped data and control interfaces
 *	v0.17 - added new style probing
 *	v0.18 - fixed new style probing for devices with more configurations
 *	v0.19 - fixed CLOCAL handling (thanks to Richard Shih-Ping Chan)
 *	v0.20 - switched to probing on interface (rather than device) class
 *	v0.21 - revert to probing on device for devices with multiple configs
 */

/*
 * 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 02111-1307 USA
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/smp_lock.h>
#include <asm/uaccess.h>
#undef DEBUG
#include <linux/usb.h>
#include <asm/byteorder.h>

/*
 * Version Information
 */
#define DRIVER_VERSION "v0.21"
#define DRIVER_AUTHOR "Armin Fuerst, Pavel Machek, Johannes Erdfelt, Vojtech Pavlik"
#define DRIVER_DESC "USB Abstract Control Model driver for USB modems and ISDN adapters"

/*
 * CMSPAR, some architectures can't have space and mark parity.
 */

#ifndef CMSPAR
#define CMSPAR			0
#endif

/*
 * Major and minor numbers.
 */

#define ACM_TTY_MAJOR		166
#define ACM_TTY_MINORS		32

/*
 * Requests.
 */

#define USB_RT_ACM		(USB_TYPE_CLASS | USB_RECIP_INTERFACE)

#define ACM_REQ_COMMAND		0x00
#define ACM_REQ_RESPONSE	0x01
#define ACM_REQ_SET_FEATURE	0x02
#define ACM_REQ_GET_FEATURE	0x03
#define ACM_REQ_CLEAR_FEATURE	0x04

#define ACM_REQ_SET_LINE	0x20
#define ACM_REQ_GET_LINE	0x21
#define ACM_REQ_SET_CONTROL	0x22
#define ACM_REQ_SEND_BREAK	0x23

/*
 * IRQs.
 */

#define ACM_IRQ_NETWORK		0x00
#define ACM_IRQ_LINE_STATE	0x20

/*
 * Output control lines.
 */

#define ACM_CTRL_DTR		0x01
#define ACM_CTRL_RTS		0x02

/*
 * Input control lines and line errors.
 */

#define ACM_CTRL_DCD		0x01
#define ACM_CTRL_DSR		0x02
#define ACM_CTRL_BRK		0x04
#define ACM_CTRL_RI		0x08

#define ACM_CTRL_FRAMING	0x10
#define ACM_CTRL_PARITY		0x20
#define ACM_CTRL_OVERRUN	0x40

/*
 * Line speed and caracter encoding.
 */

struct acm_line {
	__u32 speed;
	__u8 stopbits;
	__u8 parity;
	__u8 databits;
} __attribute__ ((packed));

/*
 * Internal driver structures.
 */

struct acm {
	struct usb_device *dev;				/* the coresponding usb device */
	struct usb_interface *iface;			/* the interfaces - +0 control +1 data */
	struct tty_struct *tty;				/* the coresponding tty */
	struct urb *ctrlurb, *readurb, *writeurb;	/* urbs */
	struct acm_line line;				/* line coding (bits, stop, parity) */
	struct tq_struct tqueue;			/* task queue for line discipline waking up */
	unsigned int ctrlin;				/* input control lines (DCD, DSR, RI, break, overruns) */
	unsigned int ctrlout;				/* output control lines (DTR, RTS) */
	unsigned int writesize;				/* max packet size for the output bulk endpoint */
	unsigned int used;				/* someone has this acm's device open */
	unsigned int minor;				/* acm minor number */
	unsigned char throttle;				/* throttled by tty layer */
	unsigned char clocal;				/* termios CLOCAL */
};

static struct usb_driver acm_driver;
static struct tty_driver acm_tty_driver;
static struct acm *acm_table[ACM_TTY_MINORS];

#define ACM_READY(acm)	(acm && acm->dev && acm->used)

/*
 * Functions for ACM control messages.
 */

static int acm_ctrl_msg(struct acm *acm, int request, int value, void *buf, int len)
{
	int retval = usb_control_msg(acm->dev, usb_sndctrlpipe(acm->dev, 0),
		request, USB_RT_ACM, value, acm->iface[0].altsetting[0].bInterfaceNumber, buf, len, HZ * 5);
	dbg("acm_control_msg: rq: 0x%02x val: %#x len: %#x result: %d", request, value, len, retval);
	return retval < 0 ? retval : 0;
}

#define acm_set_control(acm, control)	acm_ctrl_msg(acm, ACM_REQ_SET_CONTROL, control, NULL, 0)
#define acm_set_line(acm, line)		acm_ctrl_msg(acm, ACM_REQ_SET_LINE, 0, line, sizeof(struct acm_line))
#define acm_send_break(acm, ms)		acm_ctrl_msg(acm, ACM_REQ_SEND_BREAK, ms, NULL, 0)

/*
 * Interrupt handler for various ACM control events
 */

static void acm_ctrl_irq(struct urb *urb)
{
	struct acm *acm = urb->context;
	struct usb_ctrlrequest *dr = urb->transfer_buffer;
	unsigned char *data = (unsigned char *)(dr + 1);
	int newctrl;

	if (!ACM_READY(acm)) return;

	if (urb->status < 0) {
		dbg("nonzero ctrl irq status received: %d", urb->status);
		return;
	}

	switch (dr->bRequest) {

		case ACM_IRQ_NETWORK:

			dbg("%s network", data[0] ? "connected to" : "disconnected from");
			return;

		case ACM_IRQ_LINE_STATE:

			newctrl = le16_to_cpup((__u16 *) data);

			if (acm->tty && !acm->clocal && (acm->ctrlin & ~newctrl & ACM_CTRL_DCD)) {
				dbg("calling hangup");
				tty_hangup(acm->tty);
			}

			acm->ctrlin = newctrl;

			dbg("input control lines: dcd%c dsr%c break%c ring%c framing%c parity%c overrun%c",
				acm->ctrlin & ACM_CTRL_DCD ? '+' : '-',	acm->ctrlin & ACM_CTRL_DSR ? '+' : '-',
				acm->ctrlin & ACM_CTRL_BRK ? '+' : '-',	acm->ctrlin & ACM_CTRL_RI  ? '+' : '-',
				acm->ctrlin & ACM_CTRL_FRAMING ? '+' : '-',	acm->ctrlin & ACM_CTRL_PARITY ? '+' : '-',
				acm->ctrlin & ACM_CTRL_OVERRUN ? '+' : '-');

			return;

		default:
			dbg("unknown control event received: request %d index %d len %d data0 %d data1 %d",
				dr->bRequest, dr->wIndex, dr->wLength, data[0], data[1]);
			return;
	}
}

static void acm_read_bulk(struct urb *urb)
{
	struct acm *acm = urb->context;
	struct tty_struct *tty = acm->tty;
	unsigned char *data = urb->transfer_buffer;
	int i = 0;

	if (!ACM_READY(acm)) return;

	if (urb->status)
		dbg("nonzero read bulk status received: %d", urb->status);

	if (!urb->status & !acm->throttle)  {
		for (i = 0; i < urb->actual_length && !acm->throttle; i++) {
			/* if we insert more than TTY_FLIPBUF_SIZE characters,
			 * we drop them. */
			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
				tty_flip_buffer_push(tty);
			}
			tty_insert_flip_char(tty, data[i], 0);
		}
		tty_flip_buffer_push(tty);
	}

	if (acm->throttle) {
		memmove(data, data + i, urb->actual_length - i);
		urb->actual_length -= i;
		return;
	}

	urb->actual_length = 0;
	urb->dev = acm->dev;

	if (usb_submit_urb(urb, GFP_KERNEL))
		dbg("failed resubmitting read urb");
}

static void acm_write_bulk(struct urb *urb)
{
	struct acm *acm = (struct acm *)urb->context;

	if (!ACM_READY(acm)) return;

	if (urb->status)
		dbg("nonzero write bulk status received: %d", urb->status);

	queue_task(&acm->tqueue, &tq_immediate);
	mark_bh(IMMEDIATE_BH);
}

static void acm_softint(void *private)
{
	struct acm *acm = private;
	struct tty_struct *tty = acm->tty;

	if (!ACM_READY(acm)) return;

	if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && tty->ldisc.write_wakeup)
		(tty->ldisc.write_wakeup)(tty);

	wake_up_interruptible(&tty->write_wait);
}

/*
 * TTY handlers
 */

static int acm_tty_open(struct tty_struct *tty, struct file *filp)
{
	struct acm *acm = acm_table[minor(tty->device)];

	if (!acm || !acm->dev) return -EINVAL;

	tty->driver_data = acm;
	acm->tty = tty;

	MOD_INC_USE_COUNT;

        lock_kernel();

	if (acm->used++) {
                unlock_kernel();
                return 0;
        }

        unlock_kernel();

	acm->ctrlurb->dev = acm->dev;
	if (usb_submit_urb(acm->ctrlurb, GFP_KERNEL))
		dbg("usb_submit_urb(ctrl irq) failed");

	acm->readurb->dev = acm->dev;
	if (usb_submit_urb(acm->readurb, GFP_KERNEL))
		dbg("usb_submit_urb(read bulk) failed");

	acm_set_control(acm, acm->ctrlout = ACM_CTRL_DTR | ACM_CTRL_RTS);

	/* force low_latency on so that our tty_push actually forces the data through, 
	   otherwise it is scheduled, and with high data rates data can get lost. */
	tty->low_latency = 1;

	return 0;
}

static void acm_tty_close(struct tty_struct *tty, struct file *filp)
{
	struct acm *acm = tty->driver_data;

	if (!acm || !acm->used) return;

	if (!--acm->used) {
		if (acm->dev) {
			acm_set_control(acm, acm->ctrlout = 0);
			usb_unlink_urb(acm->ctrlurb);
			usb_unlink_urb(acm->writeurb);
			usb_unlink_urb(acm->readurb);
		} else {
			tty_unregister_devfs(&acm_tty_driver, acm->minor);
			acm_table[acm->minor] = NULL;
			usb_free_urb(acm->ctrlurb);
			usb_free_urb(acm->readurb);
			usb_free_urb(acm->writeurb);
			kfree(acm);
		}
	}
	MOD_DEC_USE_COUNT;
}

static int acm_tty_write(struct tty_struct *tty, int from_user, const unsigned char *buf, int count)
{
	struct acm *acm = tty->driver_data;

	if (!ACM_READY(acm)) return -EINVAL;
	if (acm->writeurb->status == -EINPROGRESS) return 0;
	if (!count) return 0;

	count = (count > acm->writesize) ? acm->writesize : count;

	if (from_user) {
		if (copy_from_user(acm->writeurb->transfer_buffer, buf, count))
			return -EFAULT;
	} else
		memcpy(acm->writeurb->transfer_buffer, buf, count);

	acm->writeurb->transfer_buffer_length = count;
	acm->writeurb->dev = acm->dev;

	if (usb_submit_urb(acm->writeurb, GFP_KERNEL))
		dbg("usb_submit_urb(write bulk) failed");

	return count;
}

static int acm_tty_write_room(struct tty_struct *tty)
{