git.oblomov.eu Git - linux-2.6/blob - drivers/net/wireless/zd1211rw/zd_usb.c

   1 /* zd_usb.c
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  16  */
  17
  18 #include <asm/unaligned.h>
  19 #include <linux/kernel.h>
  20 #include <linux/init.h>
  21 #include <linux/module.h>
  22 #include <linux/firmware.h>
  23 #include <linux/device.h>
  24 #include <linux/errno.h>
  25 #include <linux/skbuff.h>
  26 #include <linux/usb.h>
  27 #include <linux/workqueue.h>
  28 #include <net/ieee80211.h>
  29
  30 #include "zd_def.h"
  31 #include "zd_netdev.h"
  32 #include "zd_mac.h"
  33 #include "zd_usb.h"
  34 #include "zd_util.h"
  35
  36 static struct usb_device_id usb_ids[] = {
  37         /* ZD1211 */
  38         { USB_DEVICE(0x0ace, 0x1211), .driver_info = DEVICE_ZD1211 },
  39         { USB_DEVICE(0x07b8, 0x6001), .driver_info = DEVICE_ZD1211 },
  40         { USB_DEVICE(0x126f, 0xa006), .driver_info = DEVICE_ZD1211 },
  41         { USB_DEVICE(0x6891, 0xa727), .driver_info = DEVICE_ZD1211 },
  42         { USB_DEVICE(0x0df6, 0x9071), .driver_info = DEVICE_ZD1211 },
  43         { USB_DEVICE(0x0df6, 0x9075), .driver_info = DEVICE_ZD1211 },
  44         { USB_DEVICE(0x157e, 0x300b), .driver_info = DEVICE_ZD1211 },
  45         { USB_DEVICE(0x079b, 0x004a), .driver_info = DEVICE_ZD1211 },
  46         { USB_DEVICE(0x1740, 0x2000), .driver_info = DEVICE_ZD1211 },
  47         { USB_DEVICE(0x157e, 0x3204), .driver_info = DEVICE_ZD1211 },
  48         { USB_DEVICE(0x0586, 0x3402), .driver_info = DEVICE_ZD1211 },
  49         { USB_DEVICE(0x0b3b, 0x5630), .driver_info = DEVICE_ZD1211 },
  50         { USB_DEVICE(0x0b05, 0x170c), .driver_info = DEVICE_ZD1211 },
  51         { USB_DEVICE(0x1435, 0x0711), .driver_info = DEVICE_ZD1211 },
  52         { USB_DEVICE(0x0586, 0x3409), .driver_info = DEVICE_ZD1211 },
  53         { USB_DEVICE(0x0b3b, 0x1630), .driver_info = DEVICE_ZD1211 },
  54         { USB_DEVICE(0x0586, 0x3401), .driver_info = DEVICE_ZD1211 },
  55         { USB_DEVICE(0x14ea, 0xab13), .driver_info = DEVICE_ZD1211 },
  56         { USB_DEVICE(0x13b1, 0x001e), .driver_info = DEVICE_ZD1211 },
  57         { USB_DEVICE(0x0586, 0x3407), .driver_info = DEVICE_ZD1211 },
  58         /* ZD1211B */
  59         { USB_DEVICE(0x0ace, 0x1215), .driver_info = DEVICE_ZD1211B },
  60         { USB_DEVICE(0x157e, 0x300d), .driver_info = DEVICE_ZD1211B },
  61         { USB_DEVICE(0x079b, 0x0062), .driver_info = DEVICE_ZD1211B },
  62         { USB_DEVICE(0x1582, 0x6003), .driver_info = DEVICE_ZD1211B },
  63         { USB_DEVICE(0x050d, 0x705c), .driver_info = DEVICE_ZD1211B },
  64         { USB_DEVICE(0x083a, 0x4505), .driver_info = DEVICE_ZD1211B },
  65         { USB_DEVICE(0x0471, 0x1236), .driver_info = DEVICE_ZD1211B },
  66         { USB_DEVICE(0x13b1, 0x0024), .driver_info = DEVICE_ZD1211B },
  67         { USB_DEVICE(0x0586, 0x340f), .driver_info = DEVICE_ZD1211B },
  68         { USB_DEVICE(0x0b05, 0x171b), .driver_info = DEVICE_ZD1211B },
  69         { USB_DEVICE(0x0586, 0x3410), .driver_info = DEVICE_ZD1211B },
  70         { USB_DEVICE(0x0baf, 0x0121), .driver_info = DEVICE_ZD1211B },
  71         { USB_DEVICE(0x0586, 0x3412), .driver_info = DEVICE_ZD1211B },
  72         { USB_DEVICE(0x0586, 0x3413), .driver_info = DEVICE_ZD1211B },
  73         { USB_DEVICE(0x0053, 0x5301), .driver_info = DEVICE_ZD1211B },
  74         /* "Driverless" devices that need ejecting */
  75         { USB_DEVICE(0x0ace, 0x2011), .driver_info = DEVICE_INSTALLER },
  76         { USB_DEVICE(0x0ace, 0x20ff), .driver_info = DEVICE_INSTALLER },
  77         {}
  78 };
  79
  80 MODULE_LICENSE("GPL");
  81 MODULE_DESCRIPTION("USB driver for devices with the ZD1211 chip.");
  82 MODULE_AUTHOR("Ulrich Kunitz");
  83 MODULE_AUTHOR("Daniel Drake");
  84 MODULE_VERSION("1.0");
  85 MODULE_DEVICE_TABLE(usb, usb_ids);
  86
  87 #define FW_ZD1211_PREFIX        "zd1211/zd1211_"
  88 #define FW_ZD1211B_PREFIX       "zd1211/zd1211b_"
  89
  90 /* USB device initialization */
  91
  92 static int request_fw_file(
  93         const struct firmware **fw, const char *name, struct device *device)
  94 {
  95         int r;
  96
  97         dev_dbg_f(device, "fw name %s\n", name);
  98
  99         r = request_firmware(fw, name, device);
 100         if (r)
 101                 dev_err(device,
 102                        "Could not load firmware file %s. Error number %d\n",
 103                        name, r);
 104         return r;
 105 }
 106
 107 static inline u16 get_bcdDevice(const struct usb_device *udev)
 108 {
 109         return le16_to_cpu(udev->descriptor.bcdDevice);
 110 }
 111
 112 enum upload_code_flags {
 113         REBOOT = 1,
 114 };
 115
 116 /* Ensures that MAX_TRANSFER_SIZE is even. */
 117 #define MAX_TRANSFER_SIZE (USB_MAX_TRANSFER_SIZE & ~1)
 118
 119 static int upload_code(struct usb_device *udev,
 120         const u8 *data, size_t size, u16 code_offset, int flags)
 121 {
 122         u8 *p;
 123         int r;
 124
 125         /* USB request blocks need "kmalloced" buffers.
 126          */
 127         p = kmalloc(MAX_TRANSFER_SIZE, GFP_KERNEL);
 128         if (!p) {
 129                 dev_err(&udev->dev, "out of memory\n");
 130                 r = -ENOMEM;
 131                 goto error;
 132         }
 133
 134         size &= ~1;
 135         while (size > 0) {
 136                 size_t transfer_size = size <= MAX_TRANSFER_SIZE ?
 137                         size : MAX_TRANSFER_SIZE;
 138
 139                 dev_dbg_f(&udev->dev, "transfer size %zu\n", transfer_size);
 140
 141                 memcpy(p, data, transfer_size);
 142                 r = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
 143                         USB_REQ_FIRMWARE_DOWNLOAD,
 144                         USB_DIR_OUT | USB_TYPE_VENDOR,
 145                         code_offset, 0, p, transfer_size, 1000 /* ms */);
 146                 if (r < 0) {
 147                         dev_err(&udev->dev,
 148                                "USB control request for firmware upload"
 149                                " failed. Error number %d\n", r);
 150                         goto error;
 151                 }
 152                 transfer_size = r & ~1;
 153
 154                 size -= transfer_size;
 155                 data += transfer_size;
 156                 code_offset += transfer_size/sizeof(u16);
 157         }
 158
 159         if (flags & REBOOT) {
 160                 u8 ret;
 161
 162                 r = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
 163                         USB_REQ_FIRMWARE_CONFIRM,
 164                         USB_DIR_IN | USB_TYPE_VENDOR,
 165                         0, 0, &ret, sizeof(ret), 5000 /* ms */);
 166                 if (r != sizeof(ret)) {
 167                         dev_err(&udev->dev,
 168                                 "control request firmeware confirmation failed."
 169                                 " Return value %d\n", r);
 170                         if (r >= 0)
 171                                 r = -ENODEV;
 172                         goto error;
 173                 }
 174                 if (ret & 0x80) {
 175                         dev_err(&udev->dev,
 176                                 "Internal error while downloading."
 177                                 " Firmware confirm return value %#04x\n",
 178                                 (unsigned int)ret);
 179                         r = -ENODEV;
 180                         goto error;
 181                 }
 182                 dev_dbg_f(&udev->dev, "firmware confirm return value %#04x\n",
 183                         (unsigned int)ret);
 184         }
 185
 186         r = 0;
 187 error:
 188         kfree(p);
 189         return r;
 190 }
 191
 192 static u16 get_word(const void *data, u16 offset)
 193 {
 194         const __le16 *p = data;
 195         return le16_to_cpu(p[offset]);
 196 }
 197
 198 static char *get_fw_name(char *buffer, size_t size, u8 device_type,
 199                        const char* postfix)
 200 {
 201         scnprintf(buffer, size, "%s%s",
 202                 device_type == DEVICE_ZD1211B ?
 203                         FW_ZD1211B_PREFIX : FW_ZD1211_PREFIX,
 204                 postfix);
 205         return buffer;
 206 }
 207
 208 static int handle_version_mismatch(struct usb_device *udev, u8 device_type,
 209         const struct firmware *ub_fw)
 210 {
 211         const struct firmware *ur_fw = NULL;
 212         int offset;
 213         int r = 0;
 214         char fw_name[128];
 215
 216         r = request_fw_file(&ur_fw,
 217                 get_fw_name(fw_name, sizeof(fw_name), device_type, "ur"),
 218                 &udev->dev);
 219         if (r)
 220                 goto error;
 221
 222         r = upload_code(udev, ur_fw->data, ur_fw->size, FW_START, REBOOT);
 223         if (r)
 224                 goto error;
 225
 226         offset = (E2P_BOOT_CODE_OFFSET * sizeof(u16));
 227         r = upload_code(udev, ub_fw->data + offset, ub_fw->size - offset,
 228                 E2P_START + E2P_BOOT_CODE_OFFSET, REBOOT);
 229
 230         /* At this point, the vendor driver downloads the whole firmware
 231          * image, hacks around with version IDs, and uploads it again,
 232          * completely overwriting the boot code. We do not do this here as
 233          * it is not required on any tested devices, and it is suspected to
 234          * cause problems. */
 235 error:
 236         release_firmware(ur_fw);
 237         return r;
 238 }
 239
 240 static int upload_firmware(struct usb_device *udev, u8 device_type)
 241 {
 242         int r;
 243         u16 fw_bcdDevice;
 244         u16 bcdDevice;
 245         const struct firmware *ub_fw = NULL;
 246         const struct firmware *uph_fw = NULL;
 247         char fw_name[128];
 248
 249         bcdDevice = get_bcdDevice(udev);
 250
 251         r = request_fw_file(&ub_fw,
 252                 get_fw_name(fw_name, sizeof(fw_name), device_type,  "ub"),
 253                 &udev->dev);
 254         if (r)
 255                 goto error;
 256
 257         fw_bcdDevice = get_word(ub_fw->data, E2P_DATA_OFFSET);
 258
 259         if (fw_bcdDevice != bcdDevice) {
 260                 dev_info(&udev->dev,
 261                         "firmware version %#06x and device bootcode version "
 262                         "%#06x differ\n", fw_bcdDevice, bcdDevice);
 263                 if (bcdDevice <= 0x4313)
 264                         dev_warn(&udev->dev, "device has old bootcode, please "
 265                                 "report success or failure\n");
 266
 267                 r = handle_version_mismatch(udev, device_type, ub_fw);
 268                 if (r)
 269                         goto error;
 270         } else {
 271                 dev_dbg_f(&udev->dev,
 272                         "firmware device id %#06x is equal to the "
 273                         "actual device id\n", fw_bcdDevice);
 274         }
 275
 276
 277         r = request_fw_file(&uph_fw,
 278                 get_fw_name(fw_name, sizeof(fw_name), device_type, "uphr"),
 279                 &udev->dev);
 280         if (r)
 281                 goto error;
 282
 283         r = upload_code(udev, uph_fw->data, uph_fw->size, FW_START, REBOOT);
 284         if (r) {
 285                 dev_err(&udev->dev,
 286                         "Could not upload firmware code uph. Error number %d\n",
 287                         r);
 288         }
 289
 290         /* FALL-THROUGH */
 291 error:
 292         release_firmware(ub_fw);
 293         release_firmware(uph_fw);
 294         return r;
 295 }
 296
 297 #define urb_dev(urb) (&(urb)->dev->dev)
 298
 299 static inline void handle_regs_int(struct urb *urb)
 300 {
 301         struct zd_usb *usb = urb->context;
 302         struct zd_usb_interrupt *intr = &usb->intr;
 303         int len;
 304
 305         ZD_ASSERT(in_interrupt());
 306         spin_lock(&intr->lock);
 307
 308         if (intr->read_regs_enabled) {
 309                 intr->read_regs.length = len = urb->actual_length;
 310
 311                 if (len > sizeof(intr->read_regs.buffer))
 312                         len = sizeof(intr->read_regs.buffer);
 313                 memcpy(intr->read_regs.buffer, urb->transfer_buffer, len);
 314                 intr->read_regs_enabled = 0;
 315                 complete(&intr->read_regs.completion);
 316                 goto out;
 317         }
 318
 319         dev_dbg_f(urb_dev(urb), "regs interrupt ignored\n");
 320 out:
 321         spin_unlock(&intr->lock);
 322 }
 323
 324 static inline void handle_retry_failed_int(struct urb *urb)
 325 {
 326         struct zd_usb *usb = urb->context;
 327         struct zd_mac *mac = zd_usb_to_mac(usb);
 328         struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);
 329
 330         ieee->stats.tx_errors++;
 331         ieee->ieee_stats.tx_retry_limit_exceeded++;
 332         dev_dbg_f(urb_dev(urb), "retry failed interrupt\n");
 333 }
 334
 335
 336 static void int_urb_complete(struct urb *urb)
 337 {
 338         int r;
 339         struct usb_int_header *hdr;
 340
 341         switch (urb->status) {
 342         case 0:
 343                 break;
 344         case -ESHUTDOWN:
 345         case -EINVAL:
 346         case -ENODEV:
 347         case -ENOENT:
 348         case -ECONNRESET:
 349         case -EPIPE:
 350                 goto kfree;
 351         default:
 352                 goto resubmit;
 353         }
 354
 355         if (urb->actual_length < sizeof(hdr)) {
 356                 dev_dbg_f(urb_dev(urb), "error: urb %p to small\n", urb);
 357                 goto resubmit;
 358         }
 359
 360         hdr = urb->transfer_buffer;
 361         if (hdr->type != USB_INT_TYPE) {
 362                 dev_dbg_f(urb_dev(urb), "error: urb %p wrong type\n", urb);
 363                 goto resubmit;
 364         }
 365
 366         switch (hdr->id) {
 367         case USB_INT_ID_REGS:
 368                 handle_regs_int(urb);
 369                 break;
 370         case USB_INT_ID_RETRY_FAILED:
 371                 handle_retry_failed_int(urb);
 372                 break;
 373         default:
 374                 dev_dbg_f(urb_dev(urb), "error: urb %p unknown id %x\n", urb,
 375                         (unsigned int)hdr->id);
 376                 goto resubmit;
 377         }
 378
 379 resubmit:
 380         r = usb_submit_urb(urb, GFP_ATOMIC);
 381         if (r) {
 382                 dev_dbg_f(urb_dev(urb), "resubmit urb %p\n", urb);
 383                 goto kfree;
 384         }
 385         return;
 386 kfree:
 387         kfree(urb->transfer_buffer);
 388 }
 389
 390 static inline int int_urb_interval(struct usb_device *udev)
 391 {
 392         switch (udev->speed) {
 393         case USB_SPEED_HIGH:
 394                 return 4;
 395         case USB_SPEED_LOW:
 396                 return 10;
 397         case USB_SPEED_FULL:
 398         default:
 399                 return 1;
 400         }
 401 }
 402
 403 static inline int usb_int_enabled(struct zd_usb *usb)
 404 {
 405         unsigned long flags;
 406         struct zd_usb_interrupt *intr = &usb->intr;
 407         struct urb *urb;
 408
 409         spin_lock_irqsave(&intr->lock, flags);
 410         urb = intr->urb;
 411         spin_unlock_irqrestore(&intr->lock, flags);
 412         return urb != NULL;
 413 }
 414
 415 int zd_usb_enable_int(struct zd_usb *usb)
 416 {
 417         int r;
 418         struct usb_device *udev;
 419         struct zd_usb_interrupt *intr = &usb->intr;
 420         void *transfer_buffer = NULL;
 421         struct urb *urb;
 422
 423         dev_dbg_f(zd_usb_dev(usb), "\n");
 424
 425         urb = usb_alloc_urb(0, GFP_KERNEL);
 426         if (!urb) {
 427                 r = -ENOMEM;
 428                 goto out;
 429         }
 430
 431         ZD_ASSERT(!irqs_disabled());
 432         spin_lock_irq(&intr->lock);
 433         if (intr->urb) {
 434                 spin_unlock_irq(&intr->lock);
 435                 r = 0;
 436                 goto error_free_urb;
 437         }
 438         intr->urb = urb;
 439         spin_unlock_irq(&intr->lock);
 440
 441         /* TODO: make it a DMA buffer */
 442         r = -ENOMEM;
 443         transfer_buffer = kmalloc(USB_MAX_EP_INT_BUFFER, GFP_KERNEL);
 444         if (!transfer_buffer) {
 445                 dev_dbg_f(zd_usb_dev(usb),
 446                         "couldn't allocate transfer_buffer\n");
 447                 goto error_set_urb_null;
 448         }
 449
 450         udev = zd_usb_to_usbdev(usb);
 451         usb_fill_int_urb(urb, udev, usb_rcvintpipe(udev, EP_INT_IN),
 452                          transfer_buffer, USB_MAX_EP_INT_BUFFER,
 453                          int_urb_complete, usb,
 454                          intr->interval);
 455
 456         dev_dbg_f(zd_usb_dev(usb), "submit urb %p\n", intr->urb);
 457         r = usb_submit_urb(urb, GFP_KERNEL);
 458         if (r) {
 459                 dev_dbg_f(zd_usb_dev(usb),
 460                          "Couldn't submit urb. Error number %d\n", r);
 461                 goto error;
 462         }
 463
 464         return 0;
 465 error:
 466         kfree(transfer_buffer);
 467 error_set_urb_null:
 468         spin_lock_irq(&intr->lock);
 469         intr->urb = NULL;
 470         spin_unlock_irq(&intr->lock);
 471 error_free_urb:
 472         usb_free_urb(urb);
 473 out:
 474         return r;
 475 }
 476
 477 void zd_usb_disable_int(struct zd_usb *usb)
 478 {
 479         unsigned long flags;
 480         struct zd_usb_interrupt *intr = &usb->intr;
 481         struct urb *urb;
 482
 483         spin_lock_irqsave(&intr->lock, flags);
 484         urb = intr->urb;
 485         if (!urb) {
 486                 spin_unlock_irqrestore(&intr->lock, flags);
 487                 return;
 488         }
 489         intr->urb = NULL;
 490         spin_unlock_irqrestore(&intr->lock, flags);
 491
 492         usb_kill_urb(urb);
 493         dev_dbg_f(zd_usb_dev(usb), "urb %p killed\n", urb);
 494         usb_free_urb(urb);
 495 }
 496
 497 static void handle_rx_packet(struct zd_usb *usb, const u8 *buffer,
 498                              unsigned int length)
 499 {
 500         int i;
 501         struct zd_mac *mac = zd_usb_to_mac(usb);
 502         const struct rx_length_info *length_info;
 503
 504         if (length < sizeof(struct rx_length_info)) {
 505                 /* It's not a complete packet anyhow. */
 506                 struct ieee80211_device *ieee = zd_mac_to_ieee80211(mac);
 507                 ieee->stats.rx_errors++;
 508                 ieee->stats.rx_length_errors++;
 509                 return;
 510         }
 511         length_info = (struct rx_length_info *)
 512                 (buffer + length - sizeof(struct rx_length_info));
 513
 514         /* It might be that three frames are merged into a single URB
 515          * transaction. We have to check for the length info tag.
 516          *
 517          * While testing we discovered that length_info might be unaligned,
 518          * because if USB transactions are merged, the last packet will not
 519          * be padded. Unaligned access might also happen if the length_info
 520          * structure is not present.
 521          */
 522         if (get_unaligned(&length_info->tag) == cpu_to_le16(RX_LENGTH_INFO_TAG))
 523         {
 524                 unsigned int l, k, n;
 525                 for (i = 0, l = 0;; i++) {
 526                         k = le16_to_cpu(get_unaligned(&length_info->length[i]));
 527                         if (k == 0)
 528                                 return;
 529                         n = l+k;
 530                         if (n > length)
 531                                 return;
 532                         zd_mac_rx_irq(mac, buffer+l, k);
 533                         if (i >= 2)
 534                                 return;
 535                         l = (n+3) & ~3;
 536                 }
 537         } else {
 538                 zd_mac_rx_irq(mac, buffer, length);
 539         }
 540 }
 541
 542 static void rx_urb_complete(struct urb *urb)
 543 {
 544         struct zd_usb *usb;
 545         struct zd_usb_rx *rx;
 546         const u8 *buffer;
 547         unsigned int length;
 548
 549         switch (urb->status) {
 550         case 0:
 551                 break;
 552         case -ESHUTDOWN:
 553         case -EINVAL:
 554         case -ENODEV:
 555         case -ENOENT:
 556         case -ECONNRESET:
 557         case -EPIPE:
 558                 return;
 559         default:
 560                 dev_dbg_f(urb_dev(urb), "urb %p error %d\n", urb, urb->status);
 561                 goto resubmit;
 562         }
 563
 564         buffer = urb->transfer_buffer;
 565         length = urb->actual_length;
 566         usb = urb->context;
 567         rx = &usb->rx;
 568
 569         if (length%rx->usb_packet_size > rx->usb_packet_size-4) {
 570                 /* If there is an old first fragment, we don't care. */
 571                 dev_dbg_f(urb_dev(urb), "*** first fragment ***\n");
 572                 ZD_ASSERT(length <= ARRAY_SIZE(rx->fragment));
 573                 spin_lock(&rx->lock);
 574                 memcpy(rx->fragment, buffer, length);
 575                 rx->fragment_length = length;
 576                 spin_unlock(&rx->lock);
 577                 goto resubmit;
 578         }
 579
 580         spin_lock(&rx->lock);
 581         if (rx->fragment_length > 0) {
 582                 /* We are on a second fragment, we believe */
 583                 ZD_ASSERT(length + rx->fragment_length <=
 584                           ARRAY_SIZE(rx->fragment));
 585                 dev_dbg_f(urb_dev(urb), "*** second fragment ***\n");
 586                 memcpy(rx->fragment+rx->fragment_length, buffer, length);
 587                 handle_rx_packet(usb, rx->fragment,
 588                                  rx->fragment_length + length);
 589                 rx->fragment_length = 0;
 590                 spin_unlock(&rx->lock);
 591         } else {
 592                 spin_unlock(&rx->lock);
 593                 handle_rx_packet(usb, buffer, length);
 594         }
 595
 596 resubmit:
 597         usb_submit_urb(urb, GFP_ATOMIC);
 598 }
 599
 600 static struct urb *alloc_urb(struct zd_usb *usb)
 601 {
 602         struct usb_device *udev = zd_usb_to_usbdev(usb);
 603         struct urb *urb;
 604         void *buffer;
 605
 606         urb = usb_alloc_urb(0, GFP_KERNEL);
 607         if (!urb)
 608                 return NULL;
 609         buffer = usb_buffer_alloc(udev, USB_MAX_RX_SIZE, GFP_KERNEL,
 610                                   &urb->transfer_dma);
 611         if (!buffer) {
 612                 usb_free_urb(urb);
 613                 return NULL;
 614         }
 615
 616         usb_fill_bulk_urb(urb, udev, usb_rcvbulkpipe(udev, EP_DATA_IN),
 617                           buffer, USB_MAX_RX_SIZE,
 618                           rx_urb_complete, usb);
 619         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 620
 621         return urb;
 622 }
 623
 624 static void free_urb(struct urb *urb)
 625 {
 626         if (!urb)
 627                 return;
 628         usb_buffer_free(urb->dev, urb->transfer_buffer_length,
 629                         urb->transfer_buffer, urb->transfer_dma);
 630         usb_free_urb(urb);
 631 }
 632
 633 int zd_usb_enable_rx(struct zd_usb *usb)
 634 {
 635         int i, r;
 636         struct zd_usb_rx *rx = &usb->rx;
 637         struct urb **urbs;
 638
 639         dev_dbg_f(zd_usb_dev(usb), "\n");
 640
 641         r = -ENOMEM;
 642         urbs = kcalloc(URBS_COUNT, sizeof(struct urb *), GFP_KERNEL);
 643         if (!urbs)
 644                 goto error;
 645         for (i = 0; i < URBS_COUNT; i++) {
 646                 urbs[i] = alloc_urb(usb);
 647                 if (!urbs[i])
 648                         goto error;
 649         }
 650
 651         ZD_ASSERT(!irqs_disabled());
 652         spin_lock_irq(&rx->lock);
 653         if (rx->urbs) {
 654                 spin_unlock_irq(&rx->lock);
 655                 r = 0;
 656                 goto error;
 657         }
 658         rx->urbs = urbs;
 659         rx->urbs_count = URBS_COUNT;
 660         spin_unlock_irq(&rx->lock);
 661
 662         for (i = 0; i < URBS_COUNT; i++) {
 663                 r = usb_submit_urb(urbs[i], GFP_KERNEL);
 664                 if (r)
 665                         goto error_submit;
 666         }
 667
 668         return 0;
 669 error_submit:
 670         for (i = 0; i < URBS_COUNT; i++) {
 671                 usb_kill_urb(urbs[i]);
 672         }
 673         spin_lock_irq(&rx->lock);
 674         rx->urbs = NULL;
 675         rx->urbs_count = 0;
 676         spin_unlock_irq(&rx->lock);
 677 error:
 678         if (urbs) {
 679                 for (i = 0; i < URBS_COUNT; i++)
 680                         free_urb(urbs[i]);
 681         }
 682         return r;
 683 }
 684
 685 void zd_usb_disable_rx(struct zd_usb *usb)
 686 {
 687         int i;
 688         unsigned long flags;
 689         struct urb **urbs;
 690         unsigned int count;
 691         struct zd_usb_rx *rx = &usb->rx;
 692
 693         spin_lock_irqsave(&rx->lock, flags);
 694         urbs = rx->urbs;
 695         count = rx->urbs_count;
 696         spin_unlock_irqrestore(&rx->lock, flags);
 697         if (!urbs)
 698                 return;
 699
 700         for (i = 0; i < count; i++) {
 701                 usb_kill_urb(urbs[i]);
 702                 free_urb(urbs[i]);
 703         }
 704         kfree(urbs);
 705
 706         spin_lock_irqsave(&rx->lock, flags);
 707         rx->urbs = NULL;
 708         rx->urbs_count = 0;
 709         spin_unlock_irqrestore(&rx->lock, flags);
 710 }
 711
 712 static void tx_urb_complete(struct urb *urb)
 713 {
 714         int r;
 715
 716         switch (urb->status) {
 717         case 0:
 718                 break;
 719         case -ESHUTDOWN:
 720         case -EINVAL:
 721         case -ENODEV:
 722         case -ENOENT:
 723         case -ECONNRESET:
 724         case -EPIPE:
 725                 dev_dbg_f(urb_dev(urb), "urb %p error %d\n", urb, urb->status);
 726                 break;
 727         default:
 728                 dev_dbg_f(urb_dev(urb), "urb %p error %d\n", urb, urb->status);
 729                 goto resubmit;
 730         }
 731 free_urb:
 732         usb_buffer_free(urb->dev, urb->transfer_buffer_length,
 733                         urb->transfer_buffer, urb->transfer_dma);
 734         usb_free_urb(urb);
 735         return;
 736 resubmit:
 737         r = usb_submit_urb(urb, GFP_ATOMIC);
 738         if (r) {
 739                 dev_dbg_f(urb_dev(urb), "error resubmit urb %p %d\n", urb, r);
 740                 goto free_urb;
 741         }
 742 }
 743
 744 /* Puts the frame on the USB endpoint. It doesn't wait for
 745  * completion. The frame must contain the control set.
 746  */
 747 int zd_usb_tx(struct zd_usb *usb, const u8 *frame, unsigned int length)
 748 {
 749         int r;
 750         struct usb_device *udev = zd_usb_to_usbdev(usb);
 751         struct urb *urb;
 752         void *buffer;
 753
 754         urb = usb_alloc_urb(0, GFP_ATOMIC);
 755         if (!urb) {
 756                 r = -ENOMEM;
 757                 goto out;
 758         }
 759
 760         buffer = usb_buffer_alloc(zd_usb_to_usbdev(usb), length, GFP_ATOMIC,
 761                                   &urb->transfer_dma);
 762         if (!buffer) {
 763                 r = -ENOMEM;
 764                 goto error_free_urb;
 765         }
 766         memcpy(buffer, frame, length);
 767
 768         usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT),
 769                           buffer, length, tx_urb_complete, NULL);
 770         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 771
 772         r = usb_submit_urb(urb, GFP_ATOMIC);
 773         if (r)
 774                 goto error;
 775         return 0;
 776 error:
 777         usb_buffer_free(zd_usb_to_usbdev(usb), length, buffer,
 778                         urb->transfer_dma);
 779 error_free_urb:
 780         usb_free_urb(urb);
 781 out:
 782         return r;
 783 }
 784
 785 static inline void init_usb_interrupt(struct zd_usb *usb)
 786 {
 787         struct zd_usb_interrupt *intr = &usb->intr;
 788
 789         spin_lock_init(&intr->lock);
 790         intr->interval = int_urb_interval(zd_usb_to_usbdev(usb));
 791         init_completion(&intr->read_regs.completion);
 792         intr->read_regs.cr_int_addr = cpu_to_le16((u16)CR_INTERRUPT);
 793 }
 794
 795 static inline void init_usb_rx(struct zd_usb *usb)
 796 {
 797         struct zd_usb_rx *rx = &usb->rx;
 798         spin_lock_init(&rx->lock);
 799         if (interface_to_usbdev(usb->intf)->speed == USB_SPEED_HIGH) {
 800                 rx->usb_packet_size = 512;
 801         } else {
 802                 rx->usb_packet_size = 64;
 803         }
 804         ZD_ASSERT(rx->fragment_length == 0);
 805 }
 806
 807 static inline void init_usb_tx(struct zd_usb *usb)
 808 {
 809         /* FIXME: at this point we will allocate a fixed number of urb's for
 810          * use in a cyclic scheme */
 811 }
 812
 813 void zd_usb_init(struct zd_usb *usb, struct net_device *netdev,
 814                  struct usb_interface *intf)
 815 {
 816         memset(usb, 0, sizeof(*usb));
 817         usb->intf = usb_get_intf(intf);
 818         usb_set_intfdata(usb->intf, netdev);
 819         init_usb_interrupt(usb);
 820         init_usb_tx(usb);
 821         init_usb_rx(usb);
 822 }
 823
 824 void zd_usb_clear(struct zd_usb *usb)
 825 {
 826         usb_set_intfdata(usb->intf, NULL);
 827         usb_put_intf(usb->intf);
 828         ZD_MEMCLEAR(usb, sizeof(*usb));
 829         /* FIXME: usb_interrupt, usb_tx, usb_rx? */
 830 }
 831
 832 static const char *speed(enum usb_device_speed speed)
 833 {
 834         switch (speed) {
 835         case USB_SPEED_LOW:
 836                 return "low";
 837         case USB_SPEED_FULL:
 838                 return "full";
 839         case USB_SPEED_HIGH:
 840                 return "high";
 841         default:
 842                 return "unknown speed";
 843         }
 844 }
 845
 846 static int scnprint_id(struct usb_device *udev, char *buffer, size_t size)
 847 {
 848         return scnprintf(buffer, size, "%04hx:%04hx v%04hx %s",
 849                 le16_to_cpu(udev->descriptor.idVendor),
 850                 le16_to_cpu(udev->descriptor.idProduct),
 851                 get_bcdDevice(udev),
 852                 speed(udev->speed));
 853 }
 854
 855 int zd_usb_scnprint_id(struct zd_usb *usb, char *buffer, size_t size)
 856 {
 857         struct usb_device *udev = interface_to_usbdev(usb->intf);
 858         return scnprint_id(udev, buffer, size);
 859 }
 860
 861 #ifdef DEBUG
 862 static void print_id(struct usb_device *udev)
 863 {
 864         char buffer[40];
 865
 866         scnprint_id(udev, buffer, sizeof(buffer));
 867         buffer[sizeof(buffer)-1] = 0;
 868         dev_dbg_f(&udev->dev, "%s\n", buffer);
 869 }
 870 #else
 871 #define print_id(udev) do { } while (0)
 872 #endif
 873
 874 static int eject_installer(struct usb_interface *intf)
 875 {
 876         struct usb_device *udev = interface_to_usbdev(intf);
 877         struct usb_host_interface *iface_desc = &intf->altsetting[0];
 878         struct usb_endpoint_descriptor *endpoint;
 879         unsigned char *cmd;
 880         u8 bulk_out_ep;
 881         int r;
 882
 883         /* Find bulk out endpoint */
 884         endpoint = &iface_desc->endpoint[1].desc;
 885         if ((endpoint->bEndpointAddress & USB_TYPE_MASK) == USB_DIR_OUT &&
 886             (endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
 887             USB_ENDPOINT_XFER_BULK) {
 888                 bulk_out_ep = endpoint->bEndpointAddress;
 889         } else {
 890                 dev_err(&udev->dev,
 891                         "zd1211rw: Could not find bulk out endpoint\n");
 892                 return -ENODEV;
 893         }
 894
 895         cmd = kzalloc(31, GFP_KERNEL);
 896         if (cmd == NULL)
 897                 return -ENODEV;
 898
 899         /* USB bulk command block */
 900         cmd[0] = 0x55;  /* bulk command signature */
 901         cmd[1] = 0x53;  /* bulk command signature */
 902         cmd[2] = 0x42;  /* bulk command signature */
 903         cmd[3] = 0x43;  /* bulk command signature */
 904         cmd[14] = 6;    /* command length */
 905
 906         cmd[15] = 0x1b; /* SCSI command: START STOP UNIT */
 907         cmd[19] = 0x2;  /* eject disc */
 908
 909         dev_info(&udev->dev, "Ejecting virtual installer media...\n");
 910         r = usb_bulk_msg(udev, usb_sndbulkpipe(udev, bulk_out_ep),
 911                 cmd, 31, NULL, 2000);
 912         kfree(cmd);
 913         if (r)
 914                 return r;
 915
 916         /* At this point, the device disconnects and reconnects with the real
 917          * ID numbers. */
 918
 919         usb_set_intfdata(intf, NULL);
 920         return 0;
 921 }
 922
 923 static int probe(struct usb_interface *intf, const struct usb_device_id *id)
 924 {
 925         int r;
 926         struct usb_device *udev = interface_to_usbdev(intf);
 927         struct net_device *netdev = NULL;
 928
 929         print_id(udev);
 930
 931         if (id->driver_info & DEVICE_INSTALLER)
 932                 return eject_installer(intf);
 933
 934         switch (udev->speed) {
 935         case USB_SPEED_LOW:
 936         case USB_SPEED_FULL:
 937         case USB_SPEED_HIGH:
 938                 break;
 939         default:
 940                 dev_dbg_f(&intf->dev, "Unknown USB speed\n");
 941                 r = -ENODEV;
 942                 goto error;
 943         }
 944
 945         usb_reset_device(interface_to_usbdev(intf));
 946
 947         netdev = zd_netdev_alloc(intf);
 948         if (netdev == NULL) {
 949                 r = -ENOMEM;
 950                 goto error;
 951         }
 952
 953         r = upload_firmware(udev, id->driver_info);
 954         if (r) {
 955                 dev_err(&intf->dev,
 956                        "couldn't load firmware. Error number %d\n", r);
 957                 goto error;
 958         }
 959
 960         r = usb_reset_configuration(udev);
 961         if (r) {
 962                 dev_dbg_f(&intf->dev,
 963                         "couldn't reset configuration. Error number %d\n", r);
 964                 goto error;
 965         }
 966
 967         /* At this point the interrupt endpoint is not generally enabled. We
 968          * save the USB bandwidth until the network device is opened. But
 969          * notify that the initialization of the MAC will require the
 970          * interrupts to be temporary enabled.
 971          */
 972         r = zd_mac_init_hw(zd_netdev_mac(netdev), id->driver_info);
 973         if (r) {
 974                 dev_dbg_f(&intf->dev,
 975                          "couldn't initialize mac. Error number %d\n", r);
 976                 goto error;
 977         }
 978
 979         r = register_netdev(netdev);
 980         if (r) {
 981                 dev_dbg_f(&intf->dev,
 982                          "couldn't register netdev. Error number %d\n", r);
 983                 goto error;
 984         }
 985
 986         dev_dbg_f(&intf->dev, "successful\n");
 987         dev_info(&intf->dev,"%s\n", netdev->name);
 988         return 0;
 989 error:
 990         usb_reset_device(interface_to_usbdev(intf));
 991         zd_netdev_free(netdev);
 992         return r;
 993 }
 994
 995 static void disconnect(struct usb_interface *intf)
 996 {
 997         struct net_device *netdev = zd_intf_to_netdev(intf);
 998         struct zd_mac *mac = zd_netdev_mac(netdev);
 999         struct zd_usb *usb = &mac->chip.usb;
1000
1001         /* Either something really bad happened, or we're just dealing with
1002          * a DEVICE_INSTALLER. */
1003         if (netdev == NULL)
1004                 return;
1005
1006         dev_dbg_f(zd_usb_dev(usb), "\n");
1007
1008         zd_netdev_disconnect(netdev);
1009
1010         /* Just in case something has gone wrong! */
1011         zd_usb_disable_rx(usb);
1012         zd_usb_disable_int(usb);
1013
1014         /* If the disconnect has been caused by a removal of the
1015          * driver module, the reset allows reloading of the driver. If the
1016          * reset will not be executed here, the upload of the firmware in the
1017          * probe function caused by the reloading of the driver will fail.
1018          */
1019         usb_reset_device(interface_to_usbdev(intf));
1020
1021         zd_netdev_free(netdev);
1022         dev_dbg(&intf->dev, "disconnected\n");
1023 }
1024
1025 static struct usb_driver driver = {
1026         .name           = "zd1211rw",
1027         .id_table       = usb_ids,
1028         .probe          = probe,
1029         .disconnect     = disconnect,
1030 };
1031
1032 struct workqueue_struct *zd_workqueue;
1033
1034 static int __init usb_init(void)
1035 {
1036         int r;
1037
1038         pr_debug("%s usb_init()\n", driver.name);
1039
1040         zd_workqueue = create_singlethread_workqueue(driver.name);
1041         if (zd_workqueue == NULL) {
1042                 printk(KERN_ERR "%s couldn't create workqueue\n", driver.name);
1043                 return -ENOMEM;
1044         }
1045
1046         r = usb_register(&driver);
1047         if (r) {
1048                 destroy_workqueue(zd_workqueue);
1049                 printk(KERN_ERR "%s usb_register() failed. Error number %d\n",
1050                        driver.name, r);
1051                 return r;
1052         }
1053
1054         pr_debug("%s initialized\n", driver.name);
1055         return 0;
1056 }
1057
1058 static void __exit usb_exit(void)
1059 {
1060         pr_debug("%s usb_exit()\n", driver.name);
1061         usb_deregister(&driver);
1062         destroy_workqueue(zd_workqueue);
1063 }
1064
1065 module_init(usb_init);
1066 module_exit(usb_exit);
1067
1068 static int usb_int_regs_length(unsigned int count)
1069 {
1070         return sizeof(struct usb_int_regs) + count * sizeof(struct reg_data);
1071 }
1072
1073 static void prepare_read_regs_int(struct zd_usb *usb)
1074 {
1075         struct zd_usb_interrupt *intr = &usb->intr;
1076
1077         spin_lock_irq(&intr->lock);
1078         intr->read_regs_enabled = 1;
1079         INIT_COMPLETION(intr->read_regs.completion);
1080         spin_unlock_irq(&intr->lock);
1081 }
1082
1083 static void disable_read_regs_int(struct zd_usb *usb)
1084 {
1085         struct zd_usb_interrupt *intr = &usb->intr;
1086
1087         spin_lock_irq(&intr->lock);
1088         intr->read_regs_enabled = 0;
1089         spin_unlock_irq(&intr->lock);
1090 }
1091
1092 static int get_results(struct zd_usb *usb, u16 *values,
1093                        struct usb_req_read_regs *req, unsigned int count)
1094 {
1095         int r;
1096         int i;
1097         struct zd_usb_interrupt *intr = &usb->intr;
1098         struct read_regs_int *rr = &intr->read_regs;
1099         struct usb_int_regs *regs = (struct usb_int_regs *)rr->buffer;
1100
1101         spin_lock_irq(&intr->lock);
1102
1103         r = -EIO;
1104         /* The created block size seems to be larger than expected.
1105          * However results appear to be correct.
1106          */
1107         if (rr->length < usb_int_regs_length(count)) {
1108                 dev_dbg_f(zd_usb_dev(usb),
1109                          "error: actual length %d less than expected %d\n",
1110                          rr->length, usb_int_regs_length(count));
1111                 goto error_unlock;
1112         }
1113         if (rr->length > sizeof(rr->buffer)) {
1114                 dev_dbg_f(zd_usb_dev(usb),
1115                          "error: actual length %d exceeds buffer size %zu\n",
1116                          rr->length, sizeof(rr->buffer));
1117                 goto error_unlock;
1118         }
1119
1120         for (i = 0; i < count; i++) {
1121                 struct reg_data *rd = &regs->regs[i];
1122                 if (rd->addr != req->addr[i]) {
1123                         dev_dbg_f(zd_usb_dev(usb),
1124                                  "rd[%d] addr %#06hx expected %#06hx\n", i,
1125                                  le16_to_cpu(rd->addr),
1126                                  le16_to_cpu(req->addr[i]));
1127                         goto error_unlock;
1128                 }
1129                 values[i] = le16_to_cpu(rd->value);
1130         }
1131
1132         r = 0;
1133 error_unlock:
1134         spin_unlock_irq(&intr->lock);
1135         return r;
1136 }
1137
1138 int zd_usb_ioread16v(struct zd_usb *usb, u16 *values,
1139                      const zd_addr_t *addresses, unsigned int count)
1140 {
1141         int r;
1142         int i, req_len, actual_req_len;
1143         struct usb_device *udev;
1144         struct usb_req_read_regs *req = NULL;
1145         unsigned long timeout;
1146
1147         if (count < 1) {
1148                 dev_dbg_f(zd_usb_dev(usb), "error: count is zero\n");
1149                 return -EINVAL;
1150         }
1151         if (count > USB_MAX_IOREAD16_COUNT) {
1152                 dev_dbg_f(zd_usb_dev(usb),
1153                          "error: count %u exceeds possible max %u\n",
1154                          count, USB_MAX_IOREAD16_COUNT);
1155                 return -EINVAL;
1156         }
1157         if (in_atomic()) {
1158                 dev_dbg_f(zd_usb_dev(usb),
1159                          "error: io in atomic context not supported\n");
1160                 return -EWOULDBLOCK;
1161         }
1162         if (!usb_int_enabled(usb)) {
1163                  dev_dbg_f(zd_usb_dev(usb),
1164                           "error: usb interrupt not enabled\n");
1165                 return -EWOULDBLOCK;
1166         }
1167
1168         req_len = sizeof(struct usb_req_read_regs) + count * sizeof(__le16);
1169         req = kmalloc(req_len, GFP_KERNEL);
1170         if (!req)
1171                 return -ENOMEM;
1172         req->id = cpu_to_le16(USB_REQ_READ_REGS);
1173         for (i = 0; i < count; i++)
1174                 req->addr[i] = cpu_to_le16((u16)addresses[i]);
1175
1176         udev = zd_usb_to_usbdev(usb);
1177         prepare_read_regs_int(usb);
1178         r = usb_bulk_msg(udev, usb_sndbulkpipe(udev, EP_REGS_OUT),
1179                          req, req_len, &actual_req_len, 1000 /* ms */);
1180         if (r) {
1181                 dev_dbg_f(zd_usb_dev(usb),
1182                         "error in usb_bulk_msg(). Error number %d\n", r);
1183                 goto error;
1184         }
1185         if (req_len != actual_req_len) {
1186                 dev_dbg_f(zd_usb_dev(usb), "error in usb_bulk_msg()\n"
1187                         " req_len %d != actual_req_len %d\n",
1188                         req_len, actual_req_len);
1189                 r = -EIO;
1190                 goto error;
1191         }
1192
1193         timeout = wait_for_completion_timeout(&usb->intr.read_regs.completion,
1194                                               msecs_to_jiffies(1000));
1195         if (!timeout) {
1196                 disable_read_regs_int(usb);
1197                 dev_dbg_f(zd_usb_dev(usb), "read timed out\n");
1198                 r = -ETIMEDOUT;
1199                 goto error;
1200         }
1201
1202         r = get_results(usb, values, req, count);
1203 error:
1204         kfree(req);
1205         return r;
1206 }
1207
1208 int zd_usb_iowrite16v(struct zd_usb *usb, const struct zd_ioreq16 *ioreqs,
1209                       unsigned int count)
1210 {
1211         int r;
1212         struct usb_device *udev;
1213         struct usb_req_write_regs *req = NULL;
1214         int i, req_len, actual_req_len;
1215
1216         if (count == 0)
1217                 return 0;
1218         if (count > USB_MAX_IOWRITE16_COUNT) {
1219                 dev_dbg_f(zd_usb_dev(usb),
1220                         "error: count %u exceeds possible max %u\n",
1221                         count, USB_MAX_IOWRITE16_COUNT);
1222                 return -EINVAL;
1223         }
1224         if (in_atomic()) {
1225                 dev_dbg_f(zd_usb_dev(usb),
1226                         "error: io in atomic context not supported\n");
1227                 return -EWOULDBLOCK;
1228         }
1229
1230         req_len = sizeof(struct usb_req_write_regs) +
1231                   count * sizeof(struct reg_data);
1232         req = kmalloc(req_len, GFP_KERNEL);
1233         if (!req)
1234                 return -ENOMEM;
1235
1236         req->id = cpu_to_le16(USB_REQ_WRITE_REGS);
1237         for (i = 0; i < count; i++) {
1238                 struct reg_data *rw  = &req->reg_writes[i];
1239                 rw->addr = cpu_to_le16((u16)ioreqs[i].addr);
1240                 rw->value = cpu_to_le16(ioreqs[i].value);
1241         }
1242
1243         udev = zd_usb_to_usbdev(usb);
1244         r = usb_bulk_msg(udev, usb_sndbulkpipe(udev, EP_REGS_OUT),
1245                          req, req_len, &actual_req_len, 1000 /* ms */);
1246         if (r) {
1247                 dev_dbg_f(zd_usb_dev(usb),
1248                         "error in usb_bulk_msg(). Error number %d\n", r);
1249                 goto error;
1250         }
1251         if (req_len != actual_req_len) {
1252                 dev_dbg_f(zd_usb_dev(usb),
1253                         "error in usb_bulk_msg()"
1254                         " req_len %d != actual_req_len %d\n",
1255                         req_len, actual_req_len);
1256                 r = -EIO;
1257                 goto error;
1258         }
1259
1260         /* FALL-THROUGH with r == 0 */
1261 error:
1262         kfree(req);
1263         return r;
1264 }
1265
1266 int zd_usb_rfwrite(struct zd_usb *usb, u32 value, u8 bits)
1267 {
1268         int r;
1269         struct usb_device *udev;
1270         struct usb_req_rfwrite *req = NULL;
1271         int i, req_len, actual_req_len;
1272         u16 bit_value_template;
1273
1274         if (in_atomic()) {
1275                 dev_dbg_f(zd_usb_dev(usb),
1276                         "error: io in atomic context not supported\n");
1277                 return -EWOULDBLOCK;
1278         }
1279         if (bits < USB_MIN_RFWRITE_BIT_COUNT) {
1280                 dev_dbg_f(zd_usb_dev(usb),
1281                         "error: bits %d are smaller than"
1282                         " USB_MIN_RFWRITE_BIT_COUNT %d\n",
1283                         bits, USB_MIN_RFWRITE_BIT_COUNT);
1284                 return -EINVAL;
1285         }
1286         if (bits > USB_MAX_RFWRITE_BIT_COUNT) {
1287                 dev_dbg_f(zd_usb_dev(usb),
1288                         "error: bits %d exceed USB_MAX_RFWRITE_BIT_COUNT %d\n",
1289                         bits, USB_MAX_RFWRITE_BIT_COUNT);
1290                 return -EINVAL;
1291         }
1292 #ifdef DEBUG
1293         if (value & (~0UL << bits)) {
1294                 dev_dbg_f(zd_usb_dev(usb),
1295                         "error: value %#09x has bits >= %d set\n",
1296                         value, bits);
1297                 return -EINVAL;
1298         }
1299 #endif /* DEBUG */
1300
1301         dev_dbg_f(zd_usb_dev(usb), "value %#09x bits %d\n", value, bits);
1302
1303         r = zd_usb_ioread16(usb, &bit_value_template, CR203);
1304         if (r) {
1305                 dev_dbg_f(zd_usb_dev(usb),
1306                         "error %d: Couldn't read CR203\n", r);
1307                 goto out;
1308         }
1309         bit_value_template &= ~(RF_IF_LE|RF_CLK|RF_DATA);
1310
1311         req_len = sizeof(struct usb_req_rfwrite) + bits * sizeof(__le16);
1312         req = kmalloc(req_len, GFP_KERNEL);
1313         if (!req)
1314                 return -ENOMEM;
1315
1316         req->id = cpu_to_le16(USB_REQ_WRITE_RF);
1317         /* 1: 3683a, but not used in ZYDAS driver */
1318         req->value = cpu_to_le16(2);
1319         req->bits = cpu_to_le16(bits);
1320
1321         for (i = 0; i < bits; i++) {
1322                 u16 bv = bit_value_template;
1323                 if (value & (1 << (bits-1-i)))
1324                         bv |= RF_DATA;
1325                 req->bit_values[i] = cpu_to_le16(bv);
1326         }
1327
1328         udev = zd_usb_to_usbdev(usb);
1329         r = usb_bulk_msg(udev, usb_sndbulkpipe(udev, EP_REGS_OUT),
1330                          req, req_len, &actual_req_len, 1000 /* ms */);
1331         if (r) {
1332                 dev_dbg_f(zd_usb_dev(usb),
1333                         "error in usb_bulk_msg(). Error number %d\n", r);
1334                 goto out;
1335         }
1336         if (req_len != actual_req_len) {
1337                 dev_dbg_f(zd_usb_dev(usb), "error in usb_bulk_msg()"
1338                         " req_len %d != actual_req_len %d\n",
1339                         req_len, actual_req_len);
1340                 r = -EIO;
1341                 goto out;
1342         }
1343
1344         /* FALL-THROUGH with r == 0 */
1345 out:
1346         kfree(req);
1347         return r;
1348 }