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 port = usb_serial_port_get_by_minor(co->index); 112 if (port == 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 serial = port->serial; 118 119 retval = usb_autopm_get_interface(serial->interface); 120 if (retval) 121 goto error_get_interface; 122 123 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 retval = serial->type->open(NULL, port); 155 if (retval) { 156 dev_err(&port->dev, "could not open USB console port\n"); 157 goto fail; 158 } 159 160 if (serial->type->set_termios) { 161 tty->termios.c_cflag = cflag; 162 tty_termios_encode_baud_rate(&tty->termios, baud, baud); 163 memset(&dummy, 0, sizeof(struct ktermios)); 164 serial->type->set_termios(tty, port, &dummy); 165 166 tty_port_tty_set(&port->port, NULL); 167 kfree(tty); 168 } 169 set_bit(ASYNCB_INITIALIZED, &port->port.flags); 170 } 171 /* Now that any required fake tty operations are completed restore 172 * the tty port count */ 173 --port->port.count; 174 /* The console is special in terms of closing the device so 175 * indicate this port is now acting as a system console. */ 176 port->port.console = 1; 177 178 mutex_unlock(&serial->disc_mutex); 179 return retval; 180 181 fail: 182 tty_port_tty_set(&port->port, NULL); 183 free_tty: 184 kfree(tty); 185 reset_open_count: 186 port->port.count = 0; 187 usb_autopm_put_interface(serial->interface); 188 error_get_interface: 189 usb_serial_put(serial); 190 mutex_unlock(&serial->disc_mutex); 191 return retval; 192 } 193 194 static void usb_console_write(struct console *co, 195 const char *buf, unsigned count) 196 { 197 static struct usbcons_info *info = &usbcons_info; 198 struct usb_serial_port *port = info->port; 199 struct usb_serial *serial; 200 int retval = -ENODEV; 201 202 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED) 203 return; 204 serial = port->serial; 205 206 if (count == 0) 207 return; 208 209 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count); 210 211 if (!port->port.console) { 212 dev_dbg(&port->dev, "%s - port not opened\n", __func__); 213 return; 214 } 215 216 while (count) { 217 unsigned int i; 218 unsigned int lf; 219 /* search for LF so we can insert CR if necessary */ 220 for (i = 0, lf = 0 ; i < count ; i++) { 221 if (*(buf + i) == 10) { 222 lf = 1; 223 i++; 224 break; 225 } 226 } 227 /* pass on to the driver specific version of this function if 228 it is available */ 229 retval = serial->type->write(NULL, port, buf, i); 230 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval); 231 if (lf) { 232 /* append CR after LF */ 233 unsigned char cr = 13; 234 retval = serial->type->write(NULL, port, &cr, 1); 235 dev_dbg(&port->dev, "%s - write cr: %d\n", 236 __func__, retval); 237 } 238 buf += i; 239 count -= i; 240 } 241 } 242 243 static struct tty_driver *usb_console_device(struct console *co, int *index) 244 { 245 struct tty_driver **p = (struct tty_driver **)co->data; 246 247 if (!*p) 248 return NULL; 249 250 *index = co->index; 251 return *p; 252 } 253 254 static struct console usbcons = { 255 .name = "ttyUSB", 256 .write = usb_console_write, 257 .device = usb_console_device, 258 .setup = usb_console_setup, 259 .flags = CON_PRINTBUFFER, 260 .index = -1, 261 .data = &usb_serial_tty_driver, 262 }; 263 264 void usb_serial_console_disconnect(struct usb_serial *serial) 265 { 266 if (serial && serial->port && serial->port[0] 267 && serial->port[0] == usbcons_info.port) { 268 usb_serial_console_exit(); 269 usb_serial_put(serial); 270 } 271 } 272 273 void usb_serial_console_init(int minor) 274 { 275 if (minor == 0) { 276 /* 277 * Call register_console() if this is the first device plugged 278 * in. If we call it earlier, then the callback to 279 * console_setup() will fail, as there is not a device seen by 280 * the USB subsystem yet. 281 */ 282 /* 283 * Register console. 284 * NOTES: 285 * console_setup() is called (back) immediately (from 286 * register_console). console_write() is called immediately 287 * from register_console iff CON_PRINTBUFFER is set in flags. 288 */ 289 pr_debug("registering the USB serial console.\n"); 290 register_console(&usbcons); 291 } 292 } 293 294 void usb_serial_console_exit(void) 295 { 296 if (usbcons_info.port) { 297 unregister_console(&usbcons); 298 usbcons_info.port->port.console = 0; 299 usbcons_info.port = NULL; 300 } 301 } 302 303