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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/usb/serial/console.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/usb/serial/console.c')
-rw-r--r-- | drivers/usb/serial/console.c | 304 |
1 files changed, 304 insertions, 0 deletions
diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c new file mode 100644 index 000000000..da19a5fa4 --- /dev/null +++ b/drivers/usb/serial/console.c @@ -0,0 +1,304 @@ +// 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(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_save_termios(tty); + 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; + 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; + } +} + |