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