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/init.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 51 /* 52 * The parsing of the command line works exactly like the 53 * serial.c code, except that the specifier is "ttyUSB" instead 54 * of "ttyS". 55 */ 56 static int usb_console_setup(struct console *co, char *options) 57 { 58 struct usbcons_info *info = &usbcons_info; 59 int baud = 9600; 60 int bits = 8; 61 int parity = 'n'; 62 int doflow = 0; 63 int cflag = CREAD | HUPCL | CLOCAL; 64 char *s; 65 struct usb_serial *serial; 66 struct usb_serial_port *port; 67 int retval; 68 struct tty_struct *tty = NULL; 69 struct ktermios dummy; 70 71 if (options) { 72 baud = simple_strtoul(options, NULL, 10); 73 s = options; 74 while (*s >= '0' && *s <= '9') 75 s++; 76 if (*s) 77 parity = *s++; 78 if (*s) 79 bits = *s++ - '0'; 80 if (*s) 81 doflow = (*s++ == 'r'); 82 } 83 84 /* Sane default */ 85 if (baud == 0) 86 baud = 9600; 87 88 switch (bits) { 89 case 7: 90 cflag |= CS7; 91 break; 92 default: 93 case 8: 94 cflag |= CS8; 95 break; 96 } 97 switch (parity) { 98 case 'o': case 'O': 99 cflag |= PARODD; 100 break; 101 case 'e': case 'E': 102 cflag |= PARENB; 103 break; 104 } 105 co->cflag = cflag; 106 107 /* 108 * no need to check the index here: if the index is wrong, console 109 * code won't call us 110 */ 111 serial = usb_serial_get_by_index(co->index); 112 if (serial == NULL) { 113 /* no device is connected yet, sorry :( */ 114 pr_err("No USB device connected to ttyUSB%i\n", co->index); 115 return -ENODEV; 116 } 117 118 retval = usb_autopm_get_interface(serial->interface); 119 if (retval) 120 goto error_get_interface; 121 122 port = serial->port[co->index - serial->minor]; 123 tty_port_tty_set(&port->port, NULL); 124 125 info->port = port; 126 127 ++port->port.count; 128 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) { 129 if (serial->type->set_termios) { 130 /* 131 * allocate a fake tty so the driver can initialize 132 * the termios structure, then later call set_termios to 133 * configure according to command line arguments 134 */ 135 tty = kzalloc(sizeof(*tty), GFP_KERNEL); 136 if (!tty) { 137 retval = -ENOMEM; 138 dev_err(&port->dev, "no more memory\n"); 139 goto reset_open_count; 140 } 141 kref_init(&tty->kref); 142 tty_port_tty_set(&port->port, tty); 143 tty->driver = usb_serial_tty_driver; 144 tty->index = co->index; 145 if (tty_init_termios(tty)) { 146 retval = -ENOMEM; 147 dev_err(&port->dev, "no more memory\n"); 148 goto free_tty; 149 } 150 } 151 152 /* only call the device specific open if this 153 * is the first time the port is opened */ 154 if (serial->type->open) 155 retval = serial->type->open(NULL, port); 156 else 157 retval = usb_serial_generic_open(NULL, port); 158 159 if (retval) { 160 dev_err(&port->dev, "could not open USB console port\n"); 161 goto fail; 162 } 163 164 if (serial->type->set_termios) { 165 tty->termios.c_cflag = cflag; 166 tty_termios_encode_baud_rate(&tty->termios, baud, baud); 167 memset(&dummy, 0, sizeof(struct ktermios)); 168 serial->type->set_termios(tty, port, &dummy); 169 170 tty_port_tty_set(&port->port, NULL); 171 kfree(tty); 172 } 173 set_bit(ASYNCB_INITIALIZED, &port->port.flags); 174 } 175 /* Now that any required fake tty operations are completed restore 176 * the tty port count */ 177 --port->port.count; 178 /* The console is special in terms of closing the device so 179 * indicate this port is now acting as a system console. */ 180 port->port.console = 1; 181 182 mutex_unlock(&serial->disc_mutex); 183 return retval; 184 185 fail: 186 tty_port_tty_set(&port->port, NULL); 187 free_tty: 188 kfree(tty); 189 reset_open_count: 190 port->port.count = 0; 191 usb_autopm_put_interface(serial->interface); 192 error_get_interface: 193 usb_serial_put(serial); 194 mutex_unlock(&serial->disc_mutex); 195 return retval; 196 } 197 198 static void usb_console_write(struct console *co, 199 const char *buf, unsigned count) 200 { 201 static struct usbcons_info *info = &usbcons_info; 202 struct usb_serial_port *port = info->port; 203 struct usb_serial *serial; 204 int retval = -ENODEV; 205 206 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED) 207 return; 208 serial = port->serial; 209 210 if (count == 0) 211 return; 212 213 pr_debug("%s - port %d, %d byte(s)\n", __func__, port->number, count); 214 215 if (!port->port.console) { 216 pr_debug("%s - port not opened\n", __func__); 217 return; 218 } 219 220 while (count) { 221 unsigned int i; 222 unsigned int lf; 223 /* search for LF so we can insert CR if necessary */ 224 for (i = 0, lf = 0 ; i < count ; i++) { 225 if (*(buf + i) == 10) { 226 lf = 1; 227 i++; 228 break; 229 } 230 } 231 /* pass on to the driver specific version of this function if 232 it is available */ 233 if (serial->type->write) 234 retval = serial->type->write(NULL, port, buf, i); 235 else 236 retval = usb_serial_generic_write(NULL, port, buf, i); 237 pr_debug("%s - return value : %d\n", __func__, retval); 238 if (lf) { 239 /* append CR after LF */ 240 unsigned char cr = 13; 241 if (serial->type->write) 242 retval = serial->type->write(NULL, 243 port, &cr, 1); 244 else 245 retval = usb_serial_generic_write(NULL, 246 port, &cr, 1); 247 pr_debug("%s - return value : %d\n", __func__, retval); 248 } 249 buf += i; 250 count -= i; 251 } 252 } 253 254 static struct tty_driver *usb_console_device(struct console *co, int *index) 255 { 256 struct tty_driver **p = (struct tty_driver **)co->data; 257 258 if (!*p) 259 return NULL; 260 261 *index = co->index; 262 return *p; 263 } 264 265 static struct console usbcons = { 266 .name = "ttyUSB", 267 .write = usb_console_write, 268 .device = usb_console_device, 269 .setup = usb_console_setup, 270 .flags = CON_PRINTBUFFER, 271 .index = -1, 272 .data = &usb_serial_tty_driver, 273 }; 274 275 void usb_serial_console_disconnect(struct usb_serial *serial) 276 { 277 if (serial && serial->port && serial->port[0] 278 && serial->port[0] == usbcons_info.port) { 279 usb_serial_console_exit(); 280 usb_serial_put(serial); 281 } 282 } 283 284 void usb_serial_console_init(int minor) 285 { 286 if (minor == 0) { 287 /* 288 * Call register_console() if this is the first device plugged 289 * in. If we call it earlier, then the callback to 290 * console_setup() will fail, as there is not a device seen by 291 * the USB subsystem yet. 292 */ 293 /* 294 * Register console. 295 * NOTES: 296 * console_setup() is called (back) immediately (from 297 * register_console). console_write() is called immediately 298 * from register_console iff CON_PRINTBUFFER is set in flags. 299 */ 300 pr_debug("registering the USB serial console.\n"); 301 register_console(&usbcons); 302 } 303 } 304 305 void usb_serial_console_exit(void) 306 { 307 if (usbcons_info.port) { 308 unregister_console(&usbcons); 309 usbcons_info.port->port.console = 0; 310 usbcons_info.port = NULL; 311 } 312 } 313 314