1 /* 2 * Engenio/LSI RDAC SCSI Device Handler 3 * 4 * Copyright (C) 2005 Mike Christie. All rights reserved. 5 * Copyright (C) Chandra Seetharaman, IBM Corp. 2007 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 20 * 21 */ 22 #include <scsi/scsi.h> 23 #include <scsi/scsi_eh.h> 24 #include <scsi/scsi_dh.h> 25 26 #define RDAC_NAME "rdac" 27 28 /* 29 * LSI mode page stuff 30 * 31 * These struct definitions and the forming of the 32 * mode page were taken from the LSI RDAC 2.4 GPL'd 33 * driver, and then converted to Linux conventions. 34 */ 35 #define RDAC_QUIESCENCE_TIME 20; 36 /* 37 * Page Codes 38 */ 39 #define RDAC_PAGE_CODE_REDUNDANT_CONTROLLER 0x2c 40 41 /* 42 * Controller modes definitions 43 */ 44 #define RDAC_MODE_TRANSFER_SPECIFIED_LUNS 0x02 45 46 /* 47 * RDAC Options field 48 */ 49 #define RDAC_FORCED_QUIESENCE 0x02 50 51 #define RDAC_TIMEOUT (60 * HZ) 52 #define RDAC_RETRIES 3 53 54 struct rdac_mode_6_hdr { 55 u8 data_len; 56 u8 medium_type; 57 u8 device_params; 58 u8 block_desc_len; 59 }; 60 61 struct rdac_mode_10_hdr { 62 u16 data_len; 63 u8 medium_type; 64 u8 device_params; 65 u16 reserved; 66 u16 block_desc_len; 67 }; 68 69 struct rdac_mode_common { 70 u8 controller_serial[16]; 71 u8 alt_controller_serial[16]; 72 u8 rdac_mode[2]; 73 u8 alt_rdac_mode[2]; 74 u8 quiescence_timeout; 75 u8 rdac_options; 76 }; 77 78 struct rdac_pg_legacy { 79 struct rdac_mode_6_hdr hdr; 80 u8 page_code; 81 u8 page_len; 82 struct rdac_mode_common common; 83 #define MODE6_MAX_LUN 32 84 u8 lun_table[MODE6_MAX_LUN]; 85 u8 reserved2[32]; 86 u8 reserved3; 87 u8 reserved4; 88 }; 89 90 struct rdac_pg_expanded { 91 struct rdac_mode_10_hdr hdr; 92 u8 page_code; 93 u8 subpage_code; 94 u8 page_len[2]; 95 struct rdac_mode_common common; 96 u8 lun_table[256]; 97 u8 reserved3; 98 u8 reserved4; 99 }; 100 101 struct c9_inquiry { 102 u8 peripheral_info; 103 u8 page_code; /* 0xC9 */ 104 u8 reserved1; 105 u8 page_len; 106 u8 page_id[4]; /* "vace" */ 107 u8 avte_cvp; 108 u8 path_prio; 109 u8 reserved2[38]; 110 }; 111 112 #define SUBSYS_ID_LEN 16 113 #define SLOT_ID_LEN 2 114 115 struct c4_inquiry { 116 u8 peripheral_info; 117 u8 page_code; /* 0xC4 */ 118 u8 reserved1; 119 u8 page_len; 120 u8 page_id[4]; /* "subs" */ 121 u8 subsys_id[SUBSYS_ID_LEN]; 122 u8 revision[4]; 123 u8 slot_id[SLOT_ID_LEN]; 124 u8 reserved[2]; 125 }; 126 127 struct rdac_controller { 128 u8 subsys_id[SUBSYS_ID_LEN]; 129 u8 slot_id[SLOT_ID_LEN]; 130 int use_ms10; 131 struct kref kref; 132 struct list_head node; /* list of all controllers */ 133 union { 134 struct rdac_pg_legacy legacy; 135 struct rdac_pg_expanded expanded; 136 } mode_select; 137 }; 138 struct c8_inquiry { 139 u8 peripheral_info; 140 u8 page_code; /* 0xC8 */ 141 u8 reserved1; 142 u8 page_len; 143 u8 page_id[4]; /* "edid" */ 144 u8 reserved2[3]; 145 u8 vol_uniq_id_len; 146 u8 vol_uniq_id[16]; 147 u8 vol_user_label_len; 148 u8 vol_user_label[60]; 149 u8 array_uniq_id_len; 150 u8 array_unique_id[16]; 151 u8 array_user_label_len; 152 u8 array_user_label[60]; 153 u8 lun[8]; 154 }; 155 156 struct c2_inquiry { 157 u8 peripheral_info; 158 u8 page_code; /* 0xC2 */ 159 u8 reserved1; 160 u8 page_len; 161 u8 page_id[4]; /* "swr4" */ 162 u8 sw_version[3]; 163 u8 sw_date[3]; 164 u8 features_enabled; 165 u8 max_lun_supported; 166 u8 partitions[239]; /* Total allocation length should be 0xFF */ 167 }; 168 169 struct rdac_dh_data { 170 struct rdac_controller *ctlr; 171 #define UNINITIALIZED_LUN (1 << 8) 172 unsigned lun; 173 #define RDAC_STATE_ACTIVE 0 174 #define RDAC_STATE_PASSIVE 1 175 unsigned char state; 176 177 #define RDAC_LUN_UNOWNED 0 178 #define RDAC_LUN_OWNED 1 179 #define RDAC_LUN_AVT 2 180 char lun_state; 181 unsigned char sense[SCSI_SENSE_BUFFERSIZE]; 182 union { 183 struct c2_inquiry c2; 184 struct c4_inquiry c4; 185 struct c8_inquiry c8; 186 struct c9_inquiry c9; 187 } inq; 188 }; 189 190 static const char *lun_state[] = 191 { 192 "unowned", 193 "owned", 194 "owned (AVT mode)", 195 }; 196 197 static LIST_HEAD(ctlr_list); 198 static DEFINE_SPINLOCK(list_lock); 199 200 static inline struct rdac_dh_data *get_rdac_data(struct scsi_device *sdev) 201 { 202 struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data; 203 BUG_ON(scsi_dh_data == NULL); 204 return ((struct rdac_dh_data *) scsi_dh_data->buf); 205 } 206 207 static struct request *get_rdac_req(struct scsi_device *sdev, 208 void *buffer, unsigned buflen, int rw) 209 { 210 struct request *rq; 211 struct request_queue *q = sdev->request_queue; 212 213 rq = blk_get_request(q, rw, GFP_NOIO); 214 215 if (!rq) { 216 sdev_printk(KERN_INFO, sdev, 217 "get_rdac_req: blk_get_request failed.\n"); 218 return NULL; 219 } 220 221 if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) { 222 blk_put_request(rq); 223 sdev_printk(KERN_INFO, sdev, 224 "get_rdac_req: blk_rq_map_kern failed.\n"); 225 return NULL; 226 } 227 228 memset(rq->cmd, 0, BLK_MAX_CDB); 229 230 rq->cmd_type = REQ_TYPE_BLOCK_PC; 231 rq->cmd_flags |= REQ_FAILFAST | REQ_NOMERGE; 232 rq->retries = RDAC_RETRIES; 233 rq->timeout = RDAC_TIMEOUT; 234 235 return rq; 236 } 237 238 static struct request *rdac_failover_get(struct scsi_device *sdev, 239 struct rdac_dh_data *h) 240 { 241 struct request *rq; 242 struct rdac_mode_common *common; 243 unsigned data_size; 244 245 if (h->ctlr->use_ms10) { 246 struct rdac_pg_expanded *rdac_pg; 247 248 data_size = sizeof(struct rdac_pg_expanded); 249 rdac_pg = &h->ctlr->mode_select.expanded; 250 memset(rdac_pg, 0, data_size); 251 common = &rdac_pg->common; 252 rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40; 253 rdac_pg->subpage_code = 0x1; 254 rdac_pg->page_len[0] = 0x01; 255 rdac_pg->page_len[1] = 0x28; 256 rdac_pg->lun_table[h->lun] = 0x81; 257 } else { 258 struct rdac_pg_legacy *rdac_pg; 259 260 data_size = sizeof(struct rdac_pg_legacy); 261 rdac_pg = &h->ctlr->mode_select.legacy; 262 memset(rdac_pg, 0, data_size); 263 common = &rdac_pg->common; 264 rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER; 265 rdac_pg->page_len = 0x68; 266 rdac_pg->lun_table[h->lun] = 0x81; 267 } 268 common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS; 269 common->quiescence_timeout = RDAC_QUIESCENCE_TIME; 270 common->rdac_options = RDAC_FORCED_QUIESENCE; 271 272 /* get request for block layer packet command */ 273 rq = get_rdac_req(sdev, &h->ctlr->mode_select, data_size, WRITE); 274 if (!rq) 275 return NULL; 276 277 /* Prepare the command. */ 278 if (h->ctlr->use_ms10) { 279 rq->cmd[0] = MODE_SELECT_10; 280 rq->cmd[7] = data_size >> 8; 281 rq->cmd[8] = data_size & 0xff; 282 } else { 283 rq->cmd[0] = MODE_SELECT; 284 rq->cmd[4] = data_size; 285 } 286 rq->cmd_len = COMMAND_SIZE(rq->cmd[0]); 287 288 rq->sense = h->sense; 289 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); 290 rq->sense_len = 0; 291 292 return rq; 293 } 294 295 static void release_controller(struct kref *kref) 296 { 297 struct rdac_controller *ctlr; 298 ctlr = container_of(kref, struct rdac_controller, kref); 299 300 spin_lock(&list_lock); 301 list_del(&ctlr->node); 302 spin_unlock(&list_lock); 303 kfree(ctlr); 304 } 305 306 static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id) 307 { 308 struct rdac_controller *ctlr, *tmp; 309 310 spin_lock(&list_lock); 311 312 list_for_each_entry(tmp, &ctlr_list, node) { 313 if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0) && 314 (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) { 315 kref_get(&tmp->kref); 316 spin_unlock(&list_lock); 317 return tmp; 318 } 319 } 320 ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC); 321 if (!ctlr) 322 goto done; 323 324 /* initialize fields of controller */ 325 memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN); 326 memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN); 327 kref_init(&ctlr->kref); 328 ctlr->use_ms10 = -1; 329 list_add(&ctlr->node, &ctlr_list); 330 done: 331 spin_unlock(&list_lock); 332 return ctlr; 333 } 334 335 static int submit_inquiry(struct scsi_device *sdev, int page_code, 336 unsigned int len, struct rdac_dh_data *h) 337 { 338 struct request *rq; 339 struct request_queue *q = sdev->request_queue; 340 int err = SCSI_DH_RES_TEMP_UNAVAIL; 341 342 rq = get_rdac_req(sdev, &h->inq, len, READ); 343 if (!rq) 344 goto done; 345 346 /* Prepare the command. */ 347 rq->cmd[0] = INQUIRY; 348 rq->cmd[1] = 1; 349 rq->cmd[2] = page_code; 350 rq->cmd[4] = len; 351 rq->cmd_len = COMMAND_SIZE(INQUIRY); 352 353 rq->sense = h->sense; 354 memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE); 355 rq->sense_len = 0; 356 357 err = blk_execute_rq(q, NULL, rq, 1); 358 if (err == -EIO) 359 err = SCSI_DH_IO; 360 361 blk_put_request(rq); 362 done: 363 return err; 364 } 365 366 static int get_lun(struct scsi_device *sdev, struct rdac_dh_data *h) 367 { 368 int err; 369 struct c8_inquiry *inqp; 370 371 err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry), h); 372 if (err == SCSI_DH_OK) { 373 inqp = &h->inq.c8; 374 if (inqp->page_code != 0xc8) 375 return SCSI_DH_NOSYS; 376 if (inqp->page_id[0] != 'e' || inqp->page_id[1] != 'd' || 377 inqp->page_id[2] != 'i' || inqp->page_id[3] != 'd') 378 return SCSI_DH_NOSYS; 379 h->lun = scsilun_to_int((struct scsi_lun *)inqp->lun); 380 } 381 return err; 382 } 383 384 static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h) 385 { 386 int err; 387 struct c9_inquiry *inqp; 388 389 err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry), h); 390 if (err == SCSI_DH_OK) { 391 inqp = &h->inq.c9; 392 if ((inqp->avte_cvp >> 7) == 0x1) { 393 /* LUN in AVT mode */ 394 sdev_printk(KERN_NOTICE, sdev, 395 "%s: AVT mode detected\n", 396 RDAC_NAME); 397 h->lun_state = RDAC_LUN_AVT; 398 } else if ((inqp->avte_cvp & 0x1) != 0) { 399 /* LUN was owned by the controller */ 400 h->lun_state = RDAC_LUN_OWNED; 401 } 402 } 403 404 return err; 405 } 406 407 static int initialize_controller(struct scsi_device *sdev, 408 struct rdac_dh_data *h) 409 { 410 int err; 411 struct c4_inquiry *inqp; 412 413 err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h); 414 if (err == SCSI_DH_OK) { 415 inqp = &h->inq.c4; 416 h->ctlr = get_controller(inqp->subsys_id, inqp->slot_id); 417 if (!h->ctlr) 418 err = SCSI_DH_RES_TEMP_UNAVAIL; 419 } 420 return err; 421 } 422 423 static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h) 424 { 425 int err; 426 struct c2_inquiry *inqp; 427 428 err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry), h); 429 if (err == SCSI_DH_OK) { 430 inqp = &h->inq.c2; 431 /* 432 * If more than MODE6_MAX_LUN luns are supported, use 433 * mode select 10 434 */ 435 if (inqp->max_lun_supported >= MODE6_MAX_LUN) 436 h->ctlr->use_ms10 = 1; 437 else 438 h->ctlr->use_ms10 = 0; 439 } 440 return err; 441 } 442 443 static int mode_select_handle_sense(struct scsi_device *sdev, 444 unsigned char *sensebuf) 445 { 446 struct scsi_sense_hdr sense_hdr; 447 int sense, err = SCSI_DH_IO, ret; 448 449 ret = scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE, &sense_hdr); 450 if (!ret) 451 goto done; 452 453 err = SCSI_DH_OK; 454 sense = (sense_hdr.sense_key << 16) | (sense_hdr.asc << 8) | 455 sense_hdr.ascq; 456 /* If it is retryable failure, submit the c9 inquiry again */ 457 if (sense == 0x59136 || sense == 0x68b02 || sense == 0xb8b02 || 458 sense == 0x62900) { 459 /* 0x59136 - Command lock contention 460 * 0x[6b]8b02 - Quiesense in progress or achieved 461 * 0x62900 - Power On, Reset, or Bus Device Reset 462 */ 463 err = SCSI_DH_RETRY; 464 } 465 466 if (sense) 467 sdev_printk(KERN_INFO, sdev, 468 "MODE_SELECT failed with sense 0x%x.\n", sense); 469 done: 470 return err; 471 } 472 473 static int send_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h) 474 { 475 struct request *rq; 476 struct request_queue *q = sdev->request_queue; 477 int err = SCSI_DH_RES_TEMP_UNAVAIL; 478 479 rq = rdac_failover_get(sdev, h); 480 if (!rq) 481 goto done; 482 483 sdev_printk(KERN_INFO, sdev, "queueing MODE_SELECT command.\n"); 484 485 err = blk_execute_rq(q, NULL, rq, 1); 486 if (err != SCSI_DH_OK) 487 err = mode_select_handle_sense(sdev, h->sense); 488 if (err == SCSI_DH_OK) 489 h->state = RDAC_STATE_ACTIVE; 490 491 blk_put_request(rq); 492 done: 493 return err; 494 } 495 496 static int rdac_activate(struct scsi_device *sdev) 497 { 498 struct rdac_dh_data *h = get_rdac_data(sdev); 499 int err = SCSI_DH_OK; 500 501 err = check_ownership(sdev, h); 502 if (err != SCSI_DH_OK) 503 goto done; 504 505 if (!h->ctlr) { 506 err = initialize_controller(sdev, h); 507 if (err != SCSI_DH_OK) 508 goto done; 509 } 510 511 if (h->ctlr->use_ms10 == -1) { 512 err = set_mode_select(sdev, h); 513 if (err != SCSI_DH_OK) 514 goto done; 515 } 516 if (h->lun_state == RDAC_LUN_UNOWNED) 517 err = send_mode_select(sdev, h); 518 done: 519 return err; 520 } 521 522 static int rdac_prep_fn(struct scsi_device *sdev, struct request *req) 523 { 524 struct rdac_dh_data *h = get_rdac_data(sdev); 525 int ret = BLKPREP_OK; 526 527 if (h->state != RDAC_STATE_ACTIVE) { 528 ret = BLKPREP_KILL; 529 req->cmd_flags |= REQ_QUIET; 530 } 531 return ret; 532 533 } 534 535 static int rdac_check_sense(struct scsi_device *sdev, 536 struct scsi_sense_hdr *sense_hdr) 537 { 538 struct rdac_dh_data *h = get_rdac_data(sdev); 539 switch (sense_hdr->sense_key) { 540 case NOT_READY: 541 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81) 542 /* LUN Not Ready - Storage firmware incompatible 543 * Manual code synchonisation required. 544 * 545 * Nothing we can do here. Try to bypass the path. 546 */ 547 return SUCCESS; 548 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1) 549 /* LUN Not Ready - Quiescense in progress 550 * 551 * Just retry and wait. 552 */ 553 return NEEDS_RETRY; 554 break; 555 case ILLEGAL_REQUEST: 556 if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) { 557 /* Invalid Request - Current Logical Unit Ownership. 558 * Controller is not the current owner of the LUN, 559 * Fail the path, so that the other path be used. 560 */ 561 h->state = RDAC_STATE_PASSIVE; 562 return SUCCESS; 563 } 564 break; 565 case UNIT_ATTENTION: 566 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) 567 /* 568 * Power On, Reset, or Bus Device Reset, just retry. 569 */ 570 return NEEDS_RETRY; 571 break; 572 } 573 /* success just means we do not care what scsi-ml does */ 574 return SCSI_RETURN_NOT_HANDLED; 575 } 576 577 const struct scsi_dh_devlist rdac_dev_list[] = { 578 {"IBM", "1722"}, 579 {"IBM", "1724"}, 580 {"IBM", "1726"}, 581 {"IBM", "1742"}, 582 {"IBM", "1814"}, 583 {"IBM", "1815"}, 584 {"IBM", "1818"}, 585 {"IBM", "3526"}, 586 {"SGI", "TP9400"}, 587 {"SGI", "TP9500"}, 588 {"SGI", "IS"}, 589 {"STK", "OPENstorage D280"}, 590 {"SUN", "CSM200_R"}, 591 {"SUN", "LCSM100_F"}, 592 {NULL, NULL}, 593 }; 594 595 static int rdac_bus_attach(struct scsi_device *sdev); 596 static void rdac_bus_detach(struct scsi_device *sdev); 597 598 static struct scsi_device_handler rdac_dh = { 599 .name = RDAC_NAME, 600 .module = THIS_MODULE, 601 .devlist = rdac_dev_list, 602 .prep_fn = rdac_prep_fn, 603 .check_sense = rdac_check_sense, 604 .attach = rdac_bus_attach, 605 .detach = rdac_bus_detach, 606 .activate = rdac_activate, 607 }; 608 609 static int rdac_bus_attach(struct scsi_device *sdev) 610 { 611 struct scsi_dh_data *scsi_dh_data; 612 struct rdac_dh_data *h; 613 unsigned long flags; 614 int err; 615 616 scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *) 617 + sizeof(*h) , GFP_KERNEL); 618 if (!scsi_dh_data) { 619 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n", 620 RDAC_NAME); 621 return 0; 622 } 623 624 scsi_dh_data->scsi_dh = &rdac_dh; 625 h = (struct rdac_dh_data *) scsi_dh_data->buf; 626 h->lun = UNINITIALIZED_LUN; 627 h->state = RDAC_STATE_ACTIVE; 628 629 err = get_lun(sdev, h); 630 if (err != SCSI_DH_OK) 631 goto failed; 632 633 err = check_ownership(sdev, h); 634 if (err != SCSI_DH_OK) 635 goto failed; 636 637 if (!try_module_get(THIS_MODULE)) 638 goto failed; 639 640 spin_lock_irqsave(sdev->request_queue->queue_lock, flags); 641 sdev->scsi_dh_data = scsi_dh_data; 642 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); 643 644 sdev_printk(KERN_NOTICE, sdev, 645 "%s: LUN %d (%s)\n", 646 RDAC_NAME, h->lun, lun_state[(int)h->lun_state]); 647 648 return 0; 649 650 failed: 651 kfree(scsi_dh_data); 652 sdev_printk(KERN_ERR, sdev, "%s: not attached\n", 653 RDAC_NAME); 654 return -EINVAL; 655 } 656 657 static void rdac_bus_detach( struct scsi_device *sdev ) 658 { 659 struct scsi_dh_data *scsi_dh_data; 660 struct rdac_dh_data *h; 661 unsigned long flags; 662 663 spin_lock_irqsave(sdev->request_queue->queue_lock, flags); 664 scsi_dh_data = sdev->scsi_dh_data; 665 sdev->scsi_dh_data = NULL; 666 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); 667 668 h = (struct rdac_dh_data *) scsi_dh_data->buf; 669 if (h->ctlr) 670 kref_put(&h->ctlr->kref, release_controller); 671 kfree(scsi_dh_data); 672 module_put(THIS_MODULE); 673 sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", RDAC_NAME); 674 } 675 676 677 678 static int __init rdac_init(void) 679 { 680 int r; 681 682 r = scsi_register_device_handler(&rdac_dh); 683 if (r != 0) 684 printk(KERN_ERR "Failed to register scsi device handler."); 685 return r; 686 } 687 688 static void __exit rdac_exit(void) 689 { 690 scsi_unregister_device_handler(&rdac_dh); 691 } 692 693 module_init(rdac_init); 694 module_exit(rdac_exit); 695 696 MODULE_DESCRIPTION("Multipath LSI/Engenio RDAC driver"); 697 MODULE_AUTHOR("Mike Christie, Chandra Seetharaman"); 698 MODULE_LICENSE("GPL"); 699