// SPDX-License-Identifier: GPL-2.0/* * USB Serial Console driver * * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com) * * Thanks to Randy Dunlap for the original version of this code. * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/tty.h>#include <linux/console.h>#include <linux/serial.h>#include <linux/usb.h>#include <linux/usb/serial.h> struct usbcons_info {	int			magic;	int			break_flag;	struct usb_serial_port	*port;}; static struct usbcons_info usbcons_info;static struct console usbcons; /* * ------------------------------------------------------------ * USB Serial console driver * * Much of the code here is copied from drivers/char/serial.c * and implements a phony serial console in the same way that * serial.c does so that in case some software queries it, * it will get the same results. * * Things that are different from the way the serial port code * does things, is that we call the lower level usb-serial * driver code to initialize the device, and we set the initial * console speeds based on the command line arguments. * ------------------------------------------------------------ */ static const struct tty_operations usb_console_fake_tty_ops = {}; /* * The parsing of the command line works exactly like the * serial.c code, except that the specifier is "ttyUSB" instead * of "ttyS". */static int usb_console_setup(struct console *co, char *options){	struct usbcons_info *info = &usbcons_info;	int baud = 9600;	int bits = 8;	int parity = 'n';	int doflow = 0;	int cflag = CREAD | HUPCL | CLOCAL;	char *s;	struct usb_serial *serial;	struct usb_serial_port *port;	int retval;	struct tty_struct *tty = NULL;	struct ktermios dummy; 	if (options) {		baud = simple_strtoul(options, NULL, 10);		s = options;		while (*s >= '0' && *s <= '9')			s++;		if (*s)			parity = *s++;		if (*s)			bits   = *s++ - '0';		if (*s)			doflow = (*s++ == 'r');	} 	/* Sane default */	if (baud == 0)		baud = 9600; 	switch (bits) {	case 7:		cflag |= CS7;		break;	default:	case 8:		cflag |= CS8;		break;	}	switch (parity) {	case 'o': case 'O':		cflag |= PARODD;		break;	case 'e': case 'E':		cflag |= PARENB;		break;	} 	if (doflow)		cflag |= CRTSCTS; 	/*	 * no need to check the index here: if the index is wrong, console	 * code won't call us	 */	port = usb_serial_port_get_by_minor(co->index);	if (port == NULL) {		/* no device is connected yet, sorry :( */		pr_err("No USB device connected to ttyUSB%i\n", co->index);		return -ENODEV;	}	serial = port->serial; 	retval = usb_autopm_get_interface(serial->interface);	if (retval)		goto error_get_interface; 	tty_port_tty_set(&port->port, NULL); 	info->port = port; 	++port->port.count;	if (!tty_port_initialized(&port->port)) {		if (serial->type->set_termios) {			/*			 * allocate a fake tty so the driver can initialize			 * the termios structure, then later call set_termios to			 * configure according to command line arguments			 */			tty = kzalloc_obj(*tty);			if (!tty) {				retval = -ENOMEM;				goto reset_open_count;			}			kref_init(&tty->kref);			tty->driver = usb_serial_tty_driver;			tty->index = co->index;			init_ldsem(&tty->ldisc_sem);			spin_lock_init(&tty->files_lock);			INIT_LIST_HEAD(&tty->tty_files);			kref_get(&tty->driver->kref);			__module_get(tty->driver->owner);			tty->ops = &usb_console_fake_tty_ops;			tty_init_termios(tty);			tty_port_tty_set(&port->port, tty);		} 		/* only call the device specific open if this		 * is the first time the port is opened */		retval = serial->type->open(NULL, port);		if (retval) {			dev_err(&port->dev, "could not open USB console port\n");			goto fail;		} 		if (serial->type->set_termios) {			tty->termios.c_cflag = cflag;			tty_termios_encode_baud_rate(&tty->termios, baud, baud);			memset(&dummy, 0, sizeof(struct ktermios));			serial->type->set_termios(tty, port, &dummy); 			tty_port_tty_set(&port->port, NULL);			tty_save_termios(tty);			tty_kref_put(tty);		}		tty_port_set_initialized(&port->port, true);	}	/* Now that any required fake tty operations are completed restore	 * the tty port count */	--port->port.count;	/* The console is special in terms of closing the device so	 * indicate this port is now acting as a system console. */	port->port.console = 1; 	mutex_unlock(&serial->disc_mutex);	return retval;  fail:	tty_port_tty_set(&port->port, NULL);	tty_kref_put(tty); reset_open_count:	port->port.count = 0;	info->port = NULL;	usb_autopm_put_interface(serial->interface); error_get_interface:	mutex_unlock(&serial->disc_mutex);	usb_serial_put(serial);	return retval;} static void usb_console_write(struct console *co,					const char *buf, unsigned count){	static struct usbcons_info *info = &usbcons_info;	struct usb_serial_port *port = info->port;	struct usb_serial *serial;	int retval = -ENODEV; 	if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)		return;	serial = port->serial; 	if (count == 0)		return; 	dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count); 	if (!port->port.console) {		dev_dbg(&port->dev, "%s - port not opened\n", __func__);		return;	} 	while (count) {		unsigned int i;		unsigned int lf;		/* search for LF so we can insert CR if necessary */		for (i = 0, lf = 0 ; i < count ; i++) {			if (*(buf + i) == 10) {				lf = 1;				i++;				break;			}		}		/* pass on to the driver specific version of this function if		   it is available */		retval = serial->type->write(NULL, port, buf, i);		dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval);		if (lf) {			/* append CR after LF */			unsigned char cr = 13;			retval = serial->type->write(NULL, port, &cr, 1);			dev_dbg(&port->dev, "%s - write cr: %d\n",							__func__, retval);		}		buf += i;		count -= i;	}} static struct tty_driver *usb_console_device(struct console *co, int *index){	struct tty_driver **p = (struct tty_driver **)co->data; 	if (!*p)		return NULL; 	*index = co->index;	return *p;} static struct console usbcons = {	.name =		"ttyUSB",	.write =	usb_console_write,	.device =	usb_console_device,	.setup =	usb_console_setup,	.flags =	CON_PRINTBUFFER,	.index =	-1,	.data = 	&usb_serial_tty_driver,}; void usb_serial_console_disconnect(struct usb_serial *serial){	if (serial->port[0] && serial->port[0] == usbcons_info.port) {		usb_serial_console_exit();		usb_serial_put(serial);	}} void usb_serial_console_init(int minor){	if (minor == 0) {		/*		 * Call register_console() if this is the first device plugged		 * in.  If we call it earlier, then the callback to		 * console_setup() will fail, as there is not a device seen by		 * the USB subsystem yet.		 */		/*		 * Register console.		 * NOTES:		 * console_setup() is called (back) immediately (from		 * register_console). console_write() is called immediately		 * from register_console iff CON_PRINTBUFFER is set in flags.		 */		pr_debug("registering the USB serial console.\n");		register_console(&usbcons);	}} void usb_serial_console_exit(void){	if (usbcons_info.port) {		unregister_console(&usbcons);		usbcons_info.port->port.console = 0;		usbcons_info.port = NULL;	}}