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