1 /* 2 * USB Serial Console driver 3 * 4 * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License version 8 * 2 as published by the Free Software Foundation. 9 * 10 * Thanks to Randy Dunlap for the original version of this code. 11 * 12 */ 13 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/slab.h> 19 #include <linux/tty.h> 20 #include <linux/console.h> 21 #include <linux/serial.h> 22 #include <linux/usb.h> 23 #include <linux/usb/serial.h> 24 25 struct usbcons_info { 26 int magic; 27 int break_flag; 28 struct usb_serial_port *port; 29 }; 30 31 static struct usbcons_info usbcons_info; 32 static struct console usbcons; 33 34 /* 35 * ------------------------------------------------------------ 36 * USB Serial console driver 37 * 38 * Much of the code here is copied from drivers/char/serial.c 39 * and implements a phony serial console in the same way that 40 * serial.c does so that in case some software queries it, 41 * it will get the same results. 42 * 43 * Things that are different from the way the serial port code 44 * does things, is that we call the lower level usb-serial 45 * driver code to initialize the device, and we set the initial 46 * console speeds based on the command line arguments. 47 * ------------------------------------------------------------ 48 */ 49 50 static const struct tty_operations usb_console_fake_tty_ops = { 51 }; 52 53 /* 54 * The parsing of the command line works exactly like the 55 * serial.c code, except that the specifier is "ttyUSB" instead 56 * of "ttyS". 57 */ 58 static int usb_console_setup(struct console *co, char *options) 59 { 60 struct usbcons_info *info = &usbcons_info; 61 int baud = 9600; 62 int bits = 8; 63 int parity = 'n'; 64 int doflow = 0; 65 int cflag = CREAD | HUPCL | CLOCAL; 66 char *s; 67 struct usb_serial *serial; 68 struct usb_serial_port *port; 69 int retval; 70 struct tty_struct *tty = NULL; 71 struct ktermios dummy; 72 73 if (options) { 74 baud = simple_strtoul(options, NULL, 10); 75 s = options; 76 while (*s >= '0' && *s <= '9') 77 s++; 78 if (*s) 79 parity = *s++; 80 if (*s) 81 bits = *s++ - '0'; 82 if (*s) 83 doflow = (*s++ == 'r'); 84 } 85 86 /* Sane default */ 87 if (baud == 0) 88 baud = 9600; 89 90 switch (bits) { 91 case 7: 92 cflag |= CS7; 93 break; 94 default: 95 case 8: 96 cflag |= CS8; 97 break; 98 } 99 switch (parity) { 100 case 'o': case 'O': 101 cflag |= PARODD; 102 break; 103 case 'e': case 'E': 104 cflag |= PARENB; 105 break; 106 } 107 co->cflag = cflag; 108 109 /* 110 * no need to check the index here: if the index is wrong, console 111 * code won't call us 112 */ 113 port = usb_serial_port_get_by_minor(co->index); 114 if (port == NULL) { 115 /* no device is connected yet, sorry :( */ 116 pr_err("No USB device connected to ttyUSB%i\n", co->index); 117 return -ENODEV; 118 } 119 serial = port->serial; 120 121 retval = usb_autopm_get_interface(serial->interface); 122 if (retval) 123 goto error_get_interface; 124 125 tty_port_tty_set(&port->port, NULL); 126 127 info->port = port; 128 129 ++port->port.count; 130 if (!tty_port_initialized(&port->port)) { 131 if (serial->type->set_termios) { 132 /* 133 * allocate a fake tty so the driver can initialize 134 * the termios structure, then later call set_termios to 135 * configure according to command line arguments 136 */ 137 tty = kzalloc(sizeof(*tty), GFP_KERNEL); 138 if (!tty) { 139 retval = -ENOMEM; 140 goto reset_open_count; 141 } 142 kref_init(&tty->kref); 143 tty->driver = usb_serial_tty_driver; 144 tty->index = co->index; 145 init_ldsem(&tty->ldisc_sem); 146 spin_lock_init(&tty->files_lock); 147 INIT_LIST_HEAD(&tty->tty_files); 148 kref_get(&tty->driver->kref); 149 __module_get(tty->driver->owner); 150 tty->ops = &usb_console_fake_tty_ops; 151 tty_init_termios(tty); 152 tty_port_tty_set(&port->port, tty); 153 } 154 155 /* only call the device specific open if this 156 * is the first time the port is opened */ 157 retval = serial->type->open(NULL, port); 158 if (retval) { 159 dev_err(&port->dev, "could not open USB console port\n"); 160 goto fail; 161 } 162 163 if (serial->type->set_termios) { 164 tty->termios.c_cflag = cflag; 165 tty_termios_encode_baud_rate(&tty->termios, baud, baud); 166 memset(&dummy, 0, sizeof(struct ktermios)); 167 serial->type->set_termios(tty, port, &dummy); 168 169 tty_port_tty_set(&port->port, NULL); 170 tty_kref_put(tty); 171 } 172 tty_port_set_initialized(&port->port, 1); 173 } 174 /* Now that any required fake tty operations are completed restore 175 * the tty port count */ 176 --port->port.count; 177 /* The console is special in terms of closing the device so 178 * indicate this port is now acting as a system console. */ 179 port->port.console = 1; 180 181 mutex_unlock(&serial->disc_mutex); 182 return retval; 183 184 fail: 185 tty_port_tty_set(&port->port, NULL); 186 tty_kref_put(tty); 187 reset_open_count: 188 port->port.count = 0; 189 usb_autopm_put_interface(serial->interface); 190 error_get_interface: 191 usb_serial_put(serial); 192 mutex_unlock(&serial->disc_mutex); 193 return retval; 194 } 195 196 static void usb_console_write(struct console *co, 197 const char *buf, unsigned count) 198 { 199 static struct usbcons_info *info = &usbcons_info; 200 struct usb_serial_port *port = info->port; 201 struct usb_serial *serial; 202 int retval = -ENODEV; 203 204 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED) 205 return; 206 serial = port->serial; 207 208 if (count == 0) 209 return; 210 211 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count); 212 213 if (!port->port.console) { 214 dev_dbg(&port->dev, "%s - port not opened\n", __func__); 215 return; 216 } 217 218 while (count) { 219 unsigned int i; 220 unsigned int lf; 221 /* search for LF so we can insert CR if necessary */ 222 for (i = 0, lf = 0 ; i < count ; i++) { 223 if (*(buf + i) == 10) { 224 lf = 1; 225 i++; 226 break; 227 } 228 } 229 /* pass on to the driver specific version of this function if 230 it is available */ 231 retval = serial->type->write(NULL, port, buf, i); 232 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval); 233 if (lf) { 234 /* append CR after LF */ 235 unsigned char cr = 13; 236 retval = serial->type->write(NULL, port, &cr, 1); 237 dev_dbg(&port->dev, "%s - write cr: %d\n", 238 __func__, retval); 239 } 240 buf += i; 241 count -= i; 242 } 243 } 244 245 static struct tty_driver *usb_console_device(struct console *co, int *index) 246 { 247 struct tty_driver **p = (struct tty_driver **)co->data; 248 249 if (!*p) 250 return NULL; 251 252 *index = co->index; 253 return *p; 254 } 255 256 static struct console usbcons = { 257 .name = "ttyUSB", 258 .write = usb_console_write, 259 .device = usb_console_device, 260 .setup = usb_console_setup, 261 .flags = CON_PRINTBUFFER, 262 .index = -1, 263 .data = &usb_serial_tty_driver, 264 }; 265 266 void usb_serial_console_disconnect(struct usb_serial *serial) 267 { 268 if (serial->port[0] == usbcons_info.port) { 269 usb_serial_console_exit(); 270 usb_serial_put(serial); 271 } 272 } 273 274 void usb_serial_console_init(int minor) 275 { 276 if (minor == 0) { 277 /* 278 * Call register_console() if this is the first device plugged 279 * in. If we call it earlier, then the callback to 280 * console_setup() will fail, as there is not a device seen by 281 * the USB subsystem yet. 282 */ 283 /* 284 * Register console. 285 * NOTES: 286 * console_setup() is called (back) immediately (from 287 * register_console). console_write() is called immediately 288 * from register_console iff CON_PRINTBUFFER is set in flags. 289 */ 290 pr_debug("registering the USB serial console.\n"); 291 register_console(&usbcons); 292 } 293 } 294 295 void usb_serial_console_exit(void) 296 { 297 if (usbcons_info.port) { 298 unregister_console(&usbcons); 299 usbcons_info.port->port.console = 0; 300 usbcons_info.port = NULL; 301 } 302 } 303 304