linux/drivers/usb/serial/ir-usb.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * USB IR Dongle driver
   4 *
   5 *      Copyright (C) 2001-2002 Greg Kroah-Hartman (greg@kroah.com)
   6 *      Copyright (C) 2002      Gary Brubaker (xavyer@ix.netcom.com)
   7 *      Copyright (C) 2010      Johan Hovold (jhovold@gmail.com)
   8 *
   9 * This driver allows a USB IrDA device to be used as a "dumb" serial device.
  10 * This can be useful if you do not have access to a full IrDA stack on the
  11 * other side of the connection.  If you do have an IrDA stack on both devices,
  12 * please use the usb-irda driver, as it contains the proper error checking and
  13 * other goodness of a full IrDA stack.
  14 *
  15 * Portions of this driver were taken from drivers/net/irda/irda-usb.c, which
  16 * was written by Roman Weissgaerber <weissg@vienna.at>, Dag Brattli
  17 * <dag@brattli.net>, and Jean Tourrilhes <jt@hpl.hp.com>
  18 *
  19 * See Documentation/usb/usb-serial.rst for more information on using this
  20 * driver
  21 */
  22
  23#include <linux/kernel.h>
  24#include <linux/errno.h>
  25#include <linux/init.h>
  26#include <linux/slab.h>
  27#include <linux/tty.h>
  28#include <linux/tty_driver.h>
  29#include <linux/tty_flip.h>
  30#include <linux/module.h>
  31#include <linux/spinlock.h>
  32#include <linux/uaccess.h>
  33#include <linux/usb.h>
  34#include <linux/usb/serial.h>
  35#include <linux/usb/irda.h>
  36
  37#define DRIVER_AUTHOR "Greg Kroah-Hartman <greg@kroah.com>, Johan Hovold <jhovold@gmail.com>"
  38#define DRIVER_DESC "USB IR Dongle driver"
  39
  40/* if overridden by the user, then use their value for the size of the read and
  41 * write urbs */
  42static int buffer_size;
  43
  44/* if overridden by the user, then use the specified number of XBOFs */
  45static int xbof = -1;
  46
  47static int  ir_startup (struct usb_serial *serial);
  48static int ir_write(struct tty_struct *tty, struct usb_serial_port *port,
  49                const unsigned char *buf, int count);
  50static unsigned int ir_write_room(struct tty_struct *tty);
  51static void ir_write_bulk_callback(struct urb *urb);
  52static void ir_process_read_urb(struct urb *urb);
  53static void ir_set_termios(struct tty_struct *tty,
  54                struct usb_serial_port *port, struct ktermios *old_termios);
  55
  56/* Not that this lot means you can only have one per system */
  57static u8 ir_baud;
  58static u8 ir_xbof;
  59static u8 ir_add_bof;
  60
  61static const struct usb_device_id ir_id_table[] = {
  62        { USB_DEVICE(0x050f, 0x0180) },         /* KC Technology, KC-180 */
  63        { USB_DEVICE(0x08e9, 0x0100) },         /* XTNDAccess */
  64        { USB_DEVICE(0x09c4, 0x0011) },         /* ACTiSys ACT-IR2000U */
  65        { USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, USB_SUBCLASS_IRDA, 0) },
  66        { }                                     /* Terminating entry */
  67};
  68
  69MODULE_DEVICE_TABLE(usb, ir_id_table);
  70
  71static struct usb_serial_driver ir_device = {
  72        .driver = {
  73                .owner  = THIS_MODULE,
  74                .name   = "ir-usb",
  75        },
  76        .description            = "IR Dongle",
  77        .id_table               = ir_id_table,
  78        .num_ports              = 1,
  79        .num_bulk_in            = 1,
  80        .num_bulk_out           = 1,
  81        .set_termios            = ir_set_termios,
  82        .attach                 = ir_startup,
  83        .write                  = ir_write,
  84        .write_room             = ir_write_room,
  85        .write_bulk_callback    = ir_write_bulk_callback,
  86        .process_read_urb       = ir_process_read_urb,
  87};
  88
  89static struct usb_serial_driver * const serial_drivers[] = {
  90        &ir_device, NULL
  91};
  92
  93static inline void irda_usb_dump_class_desc(struct usb_serial *serial,
  94                                            struct usb_irda_cs_descriptor *desc)
  95{
  96        struct device *dev = &serial->dev->dev;
  97
  98        dev_dbg(dev, "bLength=%x\n", desc->bLength);
  99        dev_dbg(dev, "bDescriptorType=%x\n", desc->bDescriptorType);
 100        dev_dbg(dev, "bcdSpecRevision=%x\n", __le16_to_cpu(desc->bcdSpecRevision));
 101        dev_dbg(dev, "bmDataSize=%x\n", desc->bmDataSize);
 102        dev_dbg(dev, "bmWindowSize=%x\n", desc->bmWindowSize);
 103        dev_dbg(dev, "bmMinTurnaroundTime=%d\n", desc->bmMinTurnaroundTime);
 104        dev_dbg(dev, "wBaudRate=%x\n", __le16_to_cpu(desc->wBaudRate));
 105        dev_dbg(dev, "bmAdditionalBOFs=%x\n", desc->bmAdditionalBOFs);
 106        dev_dbg(dev, "bIrdaRateSniff=%x\n", desc->bIrdaRateSniff);
 107        dev_dbg(dev, "bMaxUnicastList=%x\n", desc->bMaxUnicastList);
 108}
 109
 110/*------------------------------------------------------------------*/
 111/*
 112 * Function irda_usb_find_class_desc(dev, ifnum)
 113 *
 114 *    Returns instance of IrDA class descriptor, or NULL if not found
 115 *
 116 * The class descriptor is some extra info that IrDA USB devices will
 117 * offer to us, describing their IrDA characteristics. We will use that in
 118 * irda_usb_init_qos()
 119 *
 120 * Based on the same function in drivers/net/irda/irda-usb.c
 121 */
 122static struct usb_irda_cs_descriptor *
 123irda_usb_find_class_desc(struct usb_serial *serial, unsigned int ifnum)
 124{
 125        struct usb_device *dev = serial->dev;
 126        struct usb_irda_cs_descriptor *desc;
 127        int ret;
 128
 129        desc = kzalloc(sizeof(*desc), GFP_KERNEL);
 130        if (!desc)
 131                return NULL;
 132
 133        ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
 134                        USB_REQ_CS_IRDA_GET_CLASS_DESC,
 135                        USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 136                        0, ifnum, desc, sizeof(*desc), 1000);
 137
 138        dev_dbg(&serial->dev->dev, "%s -  ret=%d\n", __func__, ret);
 139        if (ret < (int)sizeof(*desc)) {
 140                dev_dbg(&serial->dev->dev,
 141                        "%s - class descriptor read %s (%d)\n", __func__,
 142                        (ret < 0) ? "failed" : "too short", ret);
 143                goto error;
 144        }
 145        if (desc->bDescriptorType != USB_DT_CS_IRDA) {
 146                dev_dbg(&serial->dev->dev, "%s - bad class descriptor type\n",
 147                        __func__);
 148                goto error;
 149        }
 150
 151        irda_usb_dump_class_desc(serial, desc);
 152        return desc;
 153
 154error:
 155        kfree(desc);
 156        return NULL;
 157}
 158
 159static u8 ir_xbof_change(u8 xbof)
 160{
 161        u8 result;
 162
 163        /* reference irda-usb.c */
 164        switch (xbof) {
 165        case 48:
 166                result = 0x10;
 167                break;
 168        case 28:
 169        case 24:
 170                result = 0x20;
 171                break;
 172        default:
 173        case 12:
 174                result = 0x30;
 175                break;
 176        case  5:
 177        case  6:
 178                result = 0x40;
 179                break;
 180        case  3:
 181                result = 0x50;
 182                break;
 183        case  2:
 184                result = 0x60;
 185                break;
 186        case  1:
 187                result = 0x70;
 188                break;
 189        case  0:
 190                result = 0x80;
 191                break;
 192        }
 193
 194        return(result);
 195}
 196
 197static int ir_startup(struct usb_serial *serial)
 198{
 199        struct usb_irda_cs_descriptor *irda_desc;
 200        int rates;
 201
 202        irda_desc = irda_usb_find_class_desc(serial, 0);
 203        if (!irda_desc) {
 204                dev_err(&serial->dev->dev,
 205                        "IRDA class descriptor not found, device not bound\n");
 206                return -ENODEV;
 207        }
 208
 209        rates = le16_to_cpu(irda_desc->wBaudRate);
 210
 211        dev_dbg(&serial->dev->dev,
 212                "%s - Baud rates supported:%s%s%s%s%s%s%s%s%s\n",
 213                __func__,
 214                (rates & USB_IRDA_BR_2400) ? " 2400" : "",
 215                (rates & USB_IRDA_BR_9600) ? " 9600" : "",
 216                (rates & USB_IRDA_BR_19200) ? " 19200" : "",
 217                (rates & USB_IRDA_BR_38400) ? " 38400" : "",
 218                (rates & USB_IRDA_BR_57600) ? " 57600" : "",
 219                (rates & USB_IRDA_BR_115200) ? " 115200" : "",
 220                (rates & USB_IRDA_BR_576000) ? " 576000" : "",
 221                (rates & USB_IRDA_BR_1152000) ? " 1152000" : "",
 222                (rates & USB_IRDA_BR_4000000) ? " 4000000" : "");
 223
 224        switch (irda_desc->bmAdditionalBOFs) {
 225        case USB_IRDA_AB_48:
 226                ir_add_bof = 48;
 227                break;
 228        case USB_IRDA_AB_24:
 229                ir_add_bof = 24;
 230                break;
 231        case USB_IRDA_AB_12:
 232                ir_add_bof = 12;
 233                break;
 234        case USB_IRDA_AB_6:
 235                ir_add_bof = 6;
 236                break;
 237        case USB_IRDA_AB_3:
 238                ir_add_bof = 3;
 239                break;
 240        case USB_IRDA_AB_2:
 241                ir_add_bof = 2;
 242                break;
 243        case USB_IRDA_AB_1:
 244                ir_add_bof = 1;
 245                break;
 246        case USB_IRDA_AB_0:
 247                ir_add_bof = 0;
 248                break;
 249        default:
 250                break;
 251        }
 252
 253        kfree(irda_desc);
 254
 255        return 0;
 256}
 257
 258static int ir_write(struct tty_struct *tty, struct usb_serial_port *port,
 259                const unsigned char *buf, int count)
 260{
 261        struct urb *urb = NULL;
 262        unsigned long flags;
 263        int ret;
 264
 265        if (port->bulk_out_size == 0)
 266                return -EINVAL;
 267
 268        if (count == 0)
 269                return 0;
 270
 271        count = min(count, port->bulk_out_size - 1);
 272
 273        spin_lock_irqsave(&port->lock, flags);
 274        if (__test_and_clear_bit(0, &port->write_urbs_free)) {
 275                urb = port->write_urbs[0];
 276                port->tx_bytes += count;
 277        }
 278        spin_unlock_irqrestore(&port->lock, flags);
 279
 280        if (!urb)
 281                return 0;
 282
 283        /*
 284         * The first byte of the packet we send to the device contains an
 285         * outbound header which indicates an additional number of BOFs and
 286         * a baud rate change.
 287         *
 288         * See section 5.4.2.2 of the USB IrDA spec.
 289         */
 290        *(u8 *)urb->transfer_buffer = ir_xbof | ir_baud;
 291
 292        memcpy(urb->transfer_buffer + 1, buf, count);
 293
 294        urb->transfer_buffer_length = count + 1;
 295        urb->transfer_flags = URB_ZERO_PACKET;
 296
 297        ret = usb_submit_urb(urb, GFP_ATOMIC);
 298        if (ret) {
 299                dev_err(&port->dev, "failed to submit write urb: %d\n", ret);
 300
 301                spin_lock_irqsave(&port->lock, flags);
 302                __set_bit(0, &port->write_urbs_free);
 303                port->tx_bytes -= count;
 304                spin_unlock_irqrestore(&port->lock, flags);
 305
 306                return ret;
 307        }
 308
 309        return count;
 310}
 311
 312static void ir_write_bulk_callback(struct urb *urb)
 313{
 314        struct usb_serial_port *port = urb->context;
 315        int status = urb->status;
 316        unsigned long flags;
 317
 318        spin_lock_irqsave(&port->lock, flags);
 319        __set_bit(0, &port->write_urbs_free);
 320        port->tx_bytes -= urb->transfer_buffer_length - 1;
 321        spin_unlock_irqrestore(&port->lock, flags);
 322
 323        switch (status) {
 324        case 0:
 325                break;
 326        case -ENOENT:
 327        case -ECONNRESET:
 328        case -ESHUTDOWN:
 329                dev_dbg(&port->dev, "write urb stopped: %d\n", status);
 330                return;
 331        case -EPIPE:
 332                dev_err(&port->dev, "write urb stopped: %d\n", status);
 333                return;
 334        default:
 335                dev_err(&port->dev, "nonzero write-urb status: %d\n", status);
 336                break;
 337        }
 338
 339        usb_serial_port_softint(port);
 340}
 341
 342static unsigned int ir_write_room(struct tty_struct *tty)
 343{
 344        struct usb_serial_port *port = tty->driver_data;
 345        unsigned int count = 0;
 346
 347        if (port->bulk_out_size == 0)
 348                return 0;
 349
 350        if (test_bit(0, &port->write_urbs_free))
 351                count = port->bulk_out_size - 1;
 352
 353        return count;
 354}
 355
 356static void ir_process_read_urb(struct urb *urb)
 357{
 358        struct usb_serial_port *port = urb->context;
 359        unsigned char *data = urb->transfer_buffer;
 360
 361        if (!urb->actual_length)
 362                return;
 363        /*
 364         * The first byte of the packet we get from the device
 365         * contains a busy indicator and baud rate change.
 366         * See section 5.4.1.2 of the USB IrDA spec.
 367         */
 368        if (*data & 0x0f)
 369                ir_baud = *data & 0x0f;
 370
 371        if (urb->actual_length == 1)
 372                return;
 373
 374        tty_insert_flip_string(&port->port, data + 1, urb->actual_length - 1);
 375        tty_flip_buffer_push(&port->port);
 376}
 377
 378static void ir_set_termios(struct tty_struct *tty,
 379                struct usb_serial_port *port, struct ktermios *old_termios)
 380{
 381        struct usb_device *udev = port->serial->dev;
 382        unsigned char *transfer_buffer;
 383        int actual_length;
 384        speed_t baud;
 385        int ir_baud;
 386        int ret;
 387
 388        baud = tty_get_baud_rate(tty);
 389
 390        /*
 391         * FIXME, we should compare the baud request against the
 392         * capability stated in the IR header that we got in the
 393         * startup function.
 394         */
 395
 396        switch (baud) {
 397        case 2400:
 398                ir_baud = USB_IRDA_LS_2400;
 399                break;
 400        case 9600:
 401                ir_baud = USB_IRDA_LS_9600;
 402                break;
 403        case 19200:
 404                ir_baud = USB_IRDA_LS_19200;
 405                break;
 406        case 38400:
 407                ir_baud = USB_IRDA_LS_38400;
 408                break;
 409        case 57600:
 410                ir_baud = USB_IRDA_LS_57600;
 411                break;
 412        case 115200:
 413                ir_baud = USB_IRDA_LS_115200;
 414                break;
 415        case 576000:
 416                ir_baud = USB_IRDA_LS_576000;
 417                break;
 418        case 1152000:
 419                ir_baud = USB_IRDA_LS_1152000;
 420                break;
 421        case 4000000:
 422                ir_baud = USB_IRDA_LS_4000000;
 423                break;
 424        default:
 425                ir_baud = USB_IRDA_LS_9600;
 426                baud = 9600;
 427        }
 428
 429        if (xbof == -1)
 430                ir_xbof = ir_xbof_change(ir_add_bof);
 431        else
 432                ir_xbof = ir_xbof_change(xbof) ;
 433
 434        /* Only speed changes are supported */
 435        tty_termios_copy_hw(&tty->termios, old_termios);
 436        tty_encode_baud_rate(tty, baud, baud);
 437
 438        /*
 439         * send the baud change out on an "empty" data packet
 440         */
 441        transfer_buffer = kmalloc(1, GFP_KERNEL);
 442        if (!transfer_buffer)
 443                return;
 444
 445        *transfer_buffer = ir_xbof | ir_baud;
 446
 447        ret = usb_bulk_msg(udev,
 448                        usb_sndbulkpipe(udev, port->bulk_out_endpointAddress),
 449                        transfer_buffer, 1, &actual_length, 5000);
 450        if (ret || actual_length != 1) {
 451                if (!ret)
 452                        ret = -EIO;
 453                dev_err(&port->dev, "failed to change line speed: %d\n", ret);
 454        }
 455
 456        kfree(transfer_buffer);
 457}
 458
 459static int __init ir_init(void)
 460{
 461        if (buffer_size) {
 462                ir_device.bulk_in_size = buffer_size;
 463                ir_device.bulk_out_size = buffer_size;
 464        }
 465
 466        return usb_serial_register_drivers(serial_drivers, KBUILD_MODNAME, ir_id_table);
 467}
 468
 469static void __exit ir_exit(void)
 470{
 471        usb_serial_deregister_drivers(serial_drivers);
 472}
 473
 474
 475module_init(ir_init);
 476module_exit(ir_exit);
 477
 478MODULE_AUTHOR(DRIVER_AUTHOR);
 479MODULE_DESCRIPTION(DRIVER_DESC);
 480MODULE_LICENSE("GPL");
 481
 482module_param(xbof, int, 0);
 483MODULE_PARM_DESC(xbof, "Force specific number of XBOFs");
 484module_param(buffer_size, int, 0);
 485MODULE_PARM_DESC(buffer_size, "Size of the transfer buffers");
 486
 487