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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#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; }}