cregit-Linux how code gets into the kernel

Release 4.11 drivers/usb/serial/console.c

/*
 * USB Serial Console driver
 *
 * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com)
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License version
 *      2 as published by the Free Software Foundation.
 *
 * 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; } co->cflag = cflag; /* * 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(sizeof(*tty), GFP_KERNEL); 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_kref_put(tty); } tty_port_set_initialized(&port->port, 1); } /* 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; usb_autopm_put_interface(serial->interface); error_get_interface: usb_serial_put(serial); mutex_unlock(&serial->disc_mutex); return retval; }

Contributors

PersonTokensPropCommitsCommitProp
Greg Kroah-Hartman32050.39%518.52%
Aristeu Sergio Rozanski Filho8012.60%311.11%
Johan Hovold629.76%414.81%
Alan Stern599.29%13.70%
Jason Wessel548.50%414.81%
Alan Cox457.09%622.22%
Kevin Hao81.26%13.70%
Peter Hurley40.63%13.70%
Stephen Rothwell20.31%13.70%
Burman Yan10.16%13.70%
Total635100.00%27100.00%


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; } }

Contributors

PersonTokensPropCommitsCommitProp
Greg Kroah-Hartman10741.96%327.27%
Paul Fulghum10039.22%19.09%
Johan Hovold2710.59%19.09%
Guennadi Liakhovetski103.92%19.09%
Alan Cox51.96%218.18%
Jason Wessel31.18%218.18%
Harvey Harrison31.18%19.09%
Total255100.00%11100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Kevin Hao53100.00%1100.00%
Total53100.00%1100.00%

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] == usbcons_info.port) { usb_serial_console_exit(); usb_serial_put(serial); } }

Contributors

PersonTokensPropCommitsCommitProp
Guennadi Liakhovetski33100.00%1100.00%
Total33100.00%1100.00%


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); } }

Contributors

PersonTokensPropCommitsCommitProp
Greg Kroah-Hartman2793.10%266.67%
Alan Cox26.90%133.33%
Total29100.00%3100.00%


void usb_serial_console_exit(void) { if (usbcons_info.port) { unregister_console(&usbcons); usbcons_info.port->port.console = 0; usbcons_info.port = NULL; } }

Contributors

PersonTokensPropCommitsCommitProp
Guennadi Liakhovetski1951.35%125.00%
Greg Kroah-Hartman1335.14%125.00%
Jason Wessel513.51%250.00%
Total37100.00%4100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Greg Kroah-Hartman55347.92%720.00%
Johan Hovold1008.67%514.29%
Paul Fulghum1008.67%12.86%
Aristeu Sergio Rozanski Filho806.93%38.57%
Kevin Hao726.24%25.71%
Jason Wessel625.37%514.29%
Alan Stern625.37%12.86%
Guennadi Liakhovetski625.37%12.86%
Alan Cox534.59%617.14%
Peter Hurley40.35%12.86%
Harvey Harrison30.26%12.86%
Stephen Rothwell20.17%12.86%
Burman Yan10.09%12.86%
Total1154100.00%35100.00%
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