linux-hardened/drivers/usb/serial/console.c
Greg Kroah-Hartman e5b1e2062e USB: serial: make minor allocation dynamic
This moves the allocation of minor device numbers from a static array to
be dynamic, using the idr interface.  This means that you could
potentially get "gaps" in a minor number range for a single USB serial
device with multiple ports, but all should still work properly.

We remove the 'minor' field from the usb_serial structure, as it no
longer makes any sense for it (use the field in the usb_serial_port
structure if you really want to know this number), and take the fact
that we were overloading a number in this field to determine if we had
initialized the minor numbers or not, and just use a flag variable
instead.

Note, we still have the limitation of 255 USB to serial devices in the
system, as that is all we are registering with the TTY layer at this
point in time.

Tested-by: Tobias Winter <tobias@linuxdingsda.de>
Reviewed-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-06-17 13:30:02 -07:00

313 lines
7.4 KiB
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/init.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.
* ------------------------------------------------------------
*/
/*
* 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 (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) {
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;
dev_err(&port->dev, "no more memory\n");
goto reset_open_count;
}
kref_init(&tty->kref);
tty_port_tty_set(&port->port, tty);
tty->driver = usb_serial_tty_driver;
tty->index = co->index;
if (tty_init_termios(tty)) {
retval = -ENOMEM;
dev_err(&port->dev, "no more memory\n");
goto free_tty;
}
}
/* only call the device specific open if this
* is the first time the port is opened */
if (serial->type->open)
retval = serial->type->open(NULL, port);
else
retval = usb_serial_generic_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);
kfree(tty);
}
set_bit(ASYNCB_INITIALIZED, &port->port.flags);
}
/* 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);
free_tty:
kfree(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;
}
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;
pr_debug("%s - minor %d, %d byte(s)\n", __func__, port->minor, count);
if (!port->port.console) {
pr_debug("%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 */
if (serial->type->write)
retval = serial->type->write(NULL, port, buf, i);
else
retval = usb_serial_generic_write(NULL, port, buf, i);
pr_debug("%s - return value : %d\n", __func__, retval);
if (lf) {
/* append CR after LF */
unsigned char cr = 13;
if (serial->type->write)
retval = serial->type->write(NULL,
port, &cr, 1);
else
retval = usb_serial_generic_write(NULL,
port, &cr, 1);
pr_debug("%s - return value : %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 && serial->port && 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;
}
}