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 (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) { 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 INIT_LIST_HEAD(&tty->tty_files); 147 kref_get(&tty->driver->kref); 148 __module_get(tty->driver->owner); 149 tty->ops = &usb_console_fake_tty_ops; 150 if (tty_init_termios(tty)) { 151 retval = -ENOMEM; 152 goto put_tty; 153 } 154 tty_port_tty_set(&port->port, tty); 155 } 156 157 /* only call the device specific open if this 158 * is the first time the port is opened */ 159 retval = serial->type->open(NULL, port); 160 if (retval) { 161 dev_err(&port->dev, "could not open USB console port\n"); 162 goto fail; 163 } 164 165 if (serial->type->set_termios) { 166 tty->termios.c_cflag = cflag; 167 tty_termios_encode_baud_rate(&tty->termios, baud, baud); 168 memset(&dummy, 0, sizeof(struct ktermios)); 169 serial->type->set_termios(tty, port, &dummy); 170 171 tty_port_tty_set(&port->port, NULL); 172 tty_kref_put(tty); 173 } 174 set_bit(ASYNCB_INITIALIZED, &port->port.flags); 175 } 176 /* Now that any required fake tty operations are completed restore 177 * the tty port count */ 178 --port->port.count; 179 /* The console is special in terms of closing the device so 180 * indicate this port is now acting as a system console. */ 181 port->port.console = 1; 182 183 mutex_unlock(&serial->disc_mutex); 184 return retval; 185 186 fail: 187 tty_port_tty_set(&port->port, NULL); 188 put_tty: 189 tty_kref_put(tty); 190 reset_open_count: 191 port->port.count = 0; 192 usb_autopm_put_interface(serial->interface); 193 error_get_interface: 194 usb_serial_put(serial); 195 mutex_unlock(&serial->disc_mutex); 196 return retval; 197 } 198 199 static void usb_console_write(struct console *co, 200 const char *buf, unsigned count) 201 { 202 static struct usbcons_info *info = &usbcons_info; 203 struct usb_serial_port *port = info->port; 204 struct usb_serial *serial; 205 int retval = -ENODEV; 206 207 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED) 208 return; 209 serial = port->serial; 210 211 if (count == 0) 212 return; 213 214 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count); 215 216 if (!port->port.console) { 217 dev_dbg(&port->dev, "%s - port not opened\n", __func__); 218 return; 219 } 220 221 while (count) { 222 unsigned int i; 223 unsigned int lf; 224 /* search for LF so we can insert CR if necessary */ 225 for (i = 0, lf = 0 ; i < count ; i++) { 226 if (*(buf + i) == 10) { 227 lf = 1; 228 i++; 229 break; 230 } 231 } 232 /* pass on to the driver specific version of this function if 233 it is available */ 234 retval = serial->type->write(NULL, port, buf, i); 235 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval); 236 if (lf) { 237 /* append CR after LF */ 238 unsigned char cr = 13; 239 retval = serial->type->write(NULL, port, &cr, 1); 240 dev_dbg(&port->dev, "%s - write cr: %d\n", 241 __func__, retval); 242 } 243 buf += i; 244 count -= i; 245 } 246 } 247 248 static struct tty_driver *usb_console_device(struct console *co, int *index) 249 { 250 struct tty_driver **p = (struct tty_driver **)co->data; 251 252 if (!*p) 253 return NULL; 254 255 *index = co->index; 256 return *p; 257 } 258 259 static struct console usbcons = { 260 .name = "ttyUSB", 261 .write = usb_console_write, 262 .device = usb_console_device, 263 .setup = usb_console_setup, 264 .flags = CON_PRINTBUFFER, 265 .index = -1, 266 .data = &usb_serial_tty_driver, 267 }; 268 269 void usb_serial_console_disconnect(struct usb_serial *serial) 270 { 271 if (serial && serial->port && serial->port[0] 272 && serial->port[0] == usbcons_info.port) { 273 usb_serial_console_exit(); 274 usb_serial_put(serial); 275 } 276 } 277 278 void usb_serial_console_init(int minor) 279 { 280 if (minor == 0) { 281 /* 282 * Call register_console() if this is the first device plugged 283 * in. If we call it earlier, then the callback to 284 * console_setup() will fail, as there is not a device seen by 285 * the USB subsystem yet. 286 */ 287 /* 288 * Register console. 289 * NOTES: 290 * console_setup() is called (back) immediately (from 291 * register_console). console_write() is called immediately 292 * from register_console iff CON_PRINTBUFFER is set in flags. 293 */ 294 pr_debug("registering the USB serial console.\n"); 295 register_console(&usbcons); 296 } 297 } 298 299 void usb_serial_console_exit(void) 300 { 301 if (usbcons_info.port) { 302 unregister_console(&usbcons); 303 usbcons_info.port->port.console = 0; 304 usbcons_info.port = NULL; 305 } 306 } 307 308