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 goto reset_open_count; 139 } 140 kref_init(&tty->kref); 141 tty_port_tty_set(&port->port, tty); 142 tty->driver = usb_serial_tty_driver; 143 tty->index = co->index; 144 if (tty_init_termios(tty)) { 145 retval = -ENOMEM; 146 goto free_tty; 147 } 148 } 149 150 /* only call the device specific open if this 151 * is the first time the port is opened */ 152 retval = serial->type->open(NULL, port); 153 if (retval) { 154 dev_err(&port->dev, "could not open USB console port\n"); 155 goto fail; 156 } 157 158 if (serial->type->set_termios) { 159 tty->termios.c_cflag = cflag; 160 tty_termios_encode_baud_rate(&tty->termios, baud, baud); 161 memset(&dummy, 0, sizeof(struct ktermios)); 162 serial->type->set_termios(tty, port, &dummy); 163 164 tty_port_tty_set(&port->port, NULL); 165 kfree(tty); 166 } 167 set_bit(ASYNCB_INITIALIZED, &port->port.flags); 168 } 169 /* Now that any required fake tty operations are completed restore 170 * the tty port count */ 171 --port->port.count; 172 /* The console is special in terms of closing the device so 173 * indicate this port is now acting as a system console. */ 174 port->port.console = 1; 175 176 mutex_unlock(&serial->disc_mutex); 177 return retval; 178 179 fail: 180 tty_port_tty_set(&port->port, NULL); 181 free_tty: 182 kfree(tty); 183 reset_open_count: 184 port->port.count = 0; 185 usb_autopm_put_interface(serial->interface); 186 error_get_interface: 187 usb_serial_put(serial); 188 mutex_unlock(&serial->disc_mutex); 189 return retval; 190 } 191 192 static void usb_console_write(struct console *co, 193 const char *buf, unsigned count) 194 { 195 static struct usbcons_info *info = &usbcons_info; 196 struct usb_serial_port *port = info->port; 197 struct usb_serial *serial; 198 int retval = -ENODEV; 199 200 if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED) 201 return; 202 serial = port->serial; 203 204 if (count == 0) 205 return; 206 207 dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count); 208 209 if (!port->port.console) { 210 dev_dbg(&port->dev, "%s - port not opened\n", __func__); 211 return; 212 } 213 214 while (count) { 215 unsigned int i; 216 unsigned int lf; 217 /* search for LF so we can insert CR if necessary */ 218 for (i = 0, lf = 0 ; i < count ; i++) { 219 if (*(buf + i) == 10) { 220 lf = 1; 221 i++; 222 break; 223 } 224 } 225 /* pass on to the driver specific version of this function if 226 it is available */ 227 retval = serial->type->write(NULL, port, buf, i); 228 dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval); 229 if (lf) { 230 /* append CR after LF */ 231 unsigned char cr = 13; 232 retval = serial->type->write(NULL, port, &cr, 1); 233 dev_dbg(&port->dev, "%s - write cr: %d\n", 234 __func__, retval); 235 } 236 buf += i; 237 count -= i; 238 } 239 } 240 241 static struct tty_driver *usb_console_device(struct console *co, int *index) 242 { 243 struct tty_driver **p = (struct tty_driver **)co->data; 244 245 if (!*p) 246 return NULL; 247 248 *index = co->index; 249 return *p; 250 } 251 252 static struct console usbcons = { 253 .name = "ttyUSB", 254 .write = usb_console_write, 255 .device = usb_console_device, 256 .setup = usb_console_setup, 257 .flags = CON_PRINTBUFFER, 258 .index = -1, 259 .data = &usb_serial_tty_driver, 260 }; 261 262 void usb_serial_console_disconnect(struct usb_serial *serial) 263 { 264 if (serial && serial->port && serial->port[0] 265 && serial->port[0] == usbcons_info.port) { 266 usb_serial_console_exit(); 267 usb_serial_put(serial); 268 } 269 } 270 271 void usb_serial_console_init(int minor) 272 { 273 if (minor == 0) { 274 /* 275 * Call register_console() if this is the first device plugged 276 * in. If we call it earlier, then the callback to 277 * console_setup() will fail, as there is not a device seen by 278 * the USB subsystem yet. 279 */ 280 /* 281 * Register console. 282 * NOTES: 283 * console_setup() is called (back) immediately (from 284 * register_console). console_write() is called immediately 285 * from register_console iff CON_PRINTBUFFER is set in flags. 286 */ 287 pr_debug("registering the USB serial console.\n"); 288 register_console(&usbcons); 289 } 290 } 291 292 void usb_serial_console_exit(void) 293 { 294 if (usbcons_info.port) { 295 unregister_console(&usbcons); 296 usbcons_info.port->port.console = 0; 297 usbcons_info.port = NULL; 298 } 299 } 300 301