git.oblomov.eu Git - linux-2.6/blob - drivers/char/hvsi.c

   1 /*
   2  * Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  17  */
  18
  19 /* Host Virtual Serial Interface (HVSI) is a protocol between the hosted OS
  20  * and the service processor on IBM pSeries servers. On these servers, there
  21  * are no serial ports under the OS's control, and sometimes there is no other
  22  * console available either. However, the service processor has two standard
  23  * serial ports, so this over-complicated protocol allows the OS to control
  24  * those ports by proxy.
  25  *
  26  * Besides data, the procotol supports the reading/writing of the serial
  27  * port's DTR line, and the reading of the CD line. This is to allow the OS to
  28  * control a modem attached to the service processor's serial port. Note that
  29  * the OS cannot change the speed of the port through this protocol.
  30  */
  31
  32 #undef DEBUG
  33
  34 #include <linux/console.h>
  35 #include <linux/ctype.h>
  36 #include <linux/delay.h>
  37 #include <linux/init.h>
  38 #include <linux/interrupt.h>
  39 #include <linux/module.h>
  40 #include <linux/major.h>
  41 #include <linux/kernel.h>
  42 #include <linux/sched.h>
  43 #include <linux/spinlock.h>
  44 #include <linux/sysrq.h>
  45 #include <linux/tty.h>
  46 #include <linux/tty_flip.h>
  47 #include <asm/hvcall.h>
  48 #include <asm/hvconsole.h>
  49 #include <asm/prom.h>
  50 #include <asm/uaccess.h>
  51 #include <asm/vio.h>
  52 #include <asm/param.h>
  53
  54 #define HVSI_MAJOR      229
  55 #define HVSI_MINOR      128
  56 #define MAX_NR_HVSI_CONSOLES 4
  57
  58 #define HVSI_TIMEOUT (5*HZ)
  59 #define HVSI_VERSION 1
  60 #define HVSI_MAX_PACKET 256
  61 #define HVSI_MAX_READ 16
  62 #define HVSI_MAX_OUTGOING_DATA 12
  63 #define N_OUTBUF 12
  64
  65 /*
  66  * we pass data via two 8-byte registers, so we would like our char arrays
  67  * properly aligned for those loads.
  68  */
  69 #define __ALIGNED__     __attribute__((__aligned__(sizeof(long))))
  70
  71 struct hvsi_struct {
  72         struct work_struct writer;
  73         struct work_struct handshaker;
  74         wait_queue_head_t emptyq; /* woken when outbuf is emptied */
  75         wait_queue_head_t stateq; /* woken when HVSI state changes */
  76         spinlock_t lock;
  77         int index;
  78         struct tty_struct *tty;
  79         unsigned int count;
  80         uint8_t throttle_buf[128];
  81         uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
  82         /* inbuf is for packet reassembly. leave a little room for leftovers. */
  83         uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
  84         uint8_t *inbuf_end;
  85         int n_throttle;
  86         int n_outbuf;
  87         uint32_t vtermno;
  88         uint32_t virq;
  89         atomic_t seqno; /* HVSI packet sequence number */
  90         uint16_t mctrl;
  91         uint8_t state;  /* HVSI protocol state */
  92         uint8_t flags;
  93 #ifdef CONFIG_MAGIC_SYSRQ
  94         uint8_t sysrq;
  95 #endif /* CONFIG_MAGIC_SYSRQ */
  96 };
  97 static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
  98
  99 static struct tty_driver *hvsi_driver;
 100 static int hvsi_count;
 101 static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
 102
 103 enum HVSI_PROTOCOL_STATE {
 104         HVSI_CLOSED,
 105         HVSI_WAIT_FOR_VER_RESPONSE,
 106         HVSI_WAIT_FOR_VER_QUERY,
 107         HVSI_OPEN,
 108         HVSI_WAIT_FOR_MCTRL_RESPONSE,
 109         HVSI_FSP_DIED,
 110 };
 111 #define HVSI_CONSOLE 0x1
 112
 113 #define VS_DATA_PACKET_HEADER           0xff
 114 #define VS_CONTROL_PACKET_HEADER        0xfe
 115 #define VS_QUERY_PACKET_HEADER          0xfd
 116 #define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc
 117
 118 /* control verbs */
 119 #define VSV_SET_MODEM_CTL    1 /* to service processor only */
 120 #define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */
 121 #define VSV_CLOSE_PROTOCOL   3
 122
 123 /* query verbs */
 124 #define VSV_SEND_VERSION_NUMBER 1
 125 #define VSV_SEND_MODEM_CTL_STATUS 2
 126
 127 /* yes, these masks are not consecutive. */
 128 #define HVSI_TSDTR 0x01
 129 #define HVSI_TSCD  0x20
 130
 131 struct hvsi_header {
 132         uint8_t  type;
 133         uint8_t  len;
 134         uint16_t seqno;
 135 } __attribute__((packed));
 136
 137 struct hvsi_data {
 138         uint8_t  type;
 139         uint8_t  len;
 140         uint16_t seqno;
 141         uint8_t  data[HVSI_MAX_OUTGOING_DATA];
 142 } __attribute__((packed));
 143
 144 struct hvsi_control {
 145         uint8_t  type;
 146         uint8_t  len;
 147         uint16_t seqno;
 148         uint16_t verb;
 149         /* optional depending on verb: */
 150         uint32_t word;
 151         uint32_t mask;
 152 } __attribute__((packed));
 153
 154 struct hvsi_query {
 155         uint8_t  type;
 156         uint8_t  len;
 157         uint16_t seqno;
 158         uint16_t verb;
 159 } __attribute__((packed));
 160
 161 struct hvsi_query_response {
 162         uint8_t  type;
 163         uint8_t  len;
 164         uint16_t seqno;
 165         uint16_t verb;
 166         uint16_t query_seqno;
 167         union {
 168                 uint8_t  version;
 169                 uint32_t mctrl_word;
 170         } u;
 171 } __attribute__((packed));
 172
 173
 174
 175 static inline int is_console(struct hvsi_struct *hp)
 176 {
 177         return hp->flags & HVSI_CONSOLE;
 178 }
 179
 180 static inline int is_open(struct hvsi_struct *hp)
 181 {
 182         /* if we're waiting for an mctrl then we're already open */
 183         return (hp->state == HVSI_OPEN)
 184                         || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
 185 }
 186
 187 static inline void print_state(struct hvsi_struct *hp)
 188 {
 189 #ifdef DEBUG
 190         static const char *state_names[] = {
 191                 "HVSI_CLOSED",
 192                 "HVSI_WAIT_FOR_VER_RESPONSE",
 193                 "HVSI_WAIT_FOR_VER_QUERY",
 194                 "HVSI_OPEN",
 195                 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
 196                 "HVSI_FSP_DIED",
 197         };
 198         const char *name = state_names[hp->state];
 199
 200         if (hp->state > ARRAY_SIZE(state_names))
 201                 name = "UNKNOWN";
 202
 203         pr_debug("hvsi%i: state = %s\n", hp->index, name);
 204 #endif /* DEBUG */
 205 }
 206
 207 static inline void __set_state(struct hvsi_struct *hp, int state)
 208 {
 209         hp->state = state;
 210         print_state(hp);
 211         wake_up_all(&hp->stateq);
 212 }
 213
 214 static inline void set_state(struct hvsi_struct *hp, int state)
 215 {
 216         unsigned long flags;
 217
 218         spin_lock_irqsave(&hp->lock, flags);
 219         __set_state(hp, state);
 220         spin_unlock_irqrestore(&hp->lock, flags);
 221 }
 222
 223 static inline int len_packet(const uint8_t *packet)
 224 {
 225         return (int)((struct hvsi_header *)packet)->len;
 226 }
 227
 228 static inline int is_header(const uint8_t *packet)
 229 {
 230         struct hvsi_header *header = (struct hvsi_header *)packet;
 231         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
 232 }
 233
 234 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
 235 {
 236         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
 237                 return 0; /* don't even have the packet header */
 238
 239         if (hp->inbuf_end < (packet + len_packet(packet)))
 240                 return 0; /* don't have the rest of the packet */
 241
 242         return 1;
 243 }
 244
 245 /* shift remaining bytes in packetbuf down */
 246 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
 247 {
 248         int remaining = (int)(hp->inbuf_end - read_to);
 249
 250         pr_debug("%s: %i chars remain\n", __FUNCTION__, remaining);
 251
 252         if (read_to != hp->inbuf)
 253                 memmove(hp->inbuf, read_to, remaining);
 254
 255         hp->inbuf_end = hp->inbuf + remaining;
 256 }
 257
 258 #ifdef DEBUG
 259 #define dbg_dump_packet(packet) dump_packet(packet)
 260 #define dbg_dump_hex(data, len) dump_hex(data, len)
 261 #else
 262 #define dbg_dump_packet(packet) do { } while (0)
 263 #define dbg_dump_hex(data, len) do { } while (0)
 264 #endif
 265
 266 static void dump_hex(const uint8_t *data, int len)
 267 {
 268         int i;
 269
 270         printk("    ");
 271         for (i=0; i < len; i++)
 272                 printk("%.2x", data[i]);
 273
 274         printk("\n    ");
 275         for (i=0; i < len; i++) {
 276                 if (isprint(data[i]))
 277                         printk("%c", data[i]);
 278                 else
 279                         printk(".");
 280         }
 281         printk("\n");
 282 }
 283
 284 static void dump_packet(uint8_t *packet)
 285 {
 286         struct hvsi_header *header = (struct hvsi_header *)packet;
 287
 288         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
 289                         header->seqno);
 290
 291         dump_hex(packet, header->len);
 292 }
 293
 294 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
 295 {
 296         unsigned long got;
 297
 298         got = hvc_get_chars(hp->vtermno, buf, count);
 299
 300         return got;
 301 }
 302
 303 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
 304         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
 305 {
 306         struct hvsi_control *header = (struct hvsi_control *)packet;
 307
 308         switch (header->verb) {
 309                 case VSV_MODEM_CTL_UPDATE:
 310                         if ((header->word & HVSI_TSCD) == 0) {
 311                                 /* CD went away; no more connection */
 312                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
 313                                 hp->mctrl &= TIOCM_CD;
 314                                 /* If userland hasn't done an open(2) yet, hp->tty is NULL. */
 315                                 if (hp->tty && !(hp->tty->flags & CLOCAL))
 316                                         *to_hangup = hp->tty;
 317                         }
 318                         break;
 319                 case VSV_CLOSE_PROTOCOL:
 320                         pr_debug("hvsi%i: service processor came back\n", hp->index);
 321                         if (hp->state != HVSI_CLOSED) {
 322                                 *to_handshake = hp;
 323                         }
 324                         break;
 325                 default:
 326                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
 327                                 hp->index);
 328                         dump_packet(packet);
 329                         break;
 330         }
 331 }
 332
 333 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
 334 {
 335         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
 336
 337         switch (hp->state) {
 338                 case HVSI_WAIT_FOR_VER_RESPONSE:
 339                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
 340                         break;
 341                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
 342                         hp->mctrl = 0;
 343                         if (resp->u.mctrl_word & HVSI_TSDTR)
 344                                 hp->mctrl |= TIOCM_DTR;
 345                         if (resp->u.mctrl_word & HVSI_TSCD)
 346                                 hp->mctrl |= TIOCM_CD;
 347                         __set_state(hp, HVSI_OPEN);
 348                         break;
 349                 default:
 350                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
 351                         dump_packet(packet);
 352                         break;
 353         }
 354 }
 355
 356 /* respond to service processor's version query */
 357 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
 358 {
 359         struct hvsi_query_response packet __ALIGNED__;
 360         int wrote;
 361
 362         packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
 363         packet.len = sizeof(struct hvsi_query_response);
 364         packet.seqno = atomic_inc_return(&hp->seqno);
 365         packet.verb = VSV_SEND_VERSION_NUMBER;
 366         packet.u.version = HVSI_VERSION;
 367         packet.query_seqno = query_seqno+1;
 368
 369         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
 370         dbg_dump_hex((uint8_t*)&packet, packet.len);
 371
 372         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 373         if (wrote != packet.len) {
 374                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
 375                         hp->index);
 376                 return -EIO;
 377         }
 378
 379         return 0;
 380 }
 381
 382 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
 383 {
 384         struct hvsi_query *query = (struct hvsi_query *)packet;
 385
 386         switch (hp->state) {
 387                 case HVSI_WAIT_FOR_VER_QUERY:
 388                         hvsi_version_respond(hp, query->seqno);
 389                         __set_state(hp, HVSI_OPEN);
 390                         break;
 391                 default:
 392                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
 393                         dump_packet(packet);
 394                         break;
 395         }
 396 }
 397
 398 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
 399 {
 400         int i;
 401
 402         for (i=0; i < len; i++) {
 403                 char c = buf[i];
 404 #ifdef CONFIG_MAGIC_SYSRQ
 405                 if (c == '\0') {
 406                         hp->sysrq = 1;
 407                         continue;
 408                 } else if (hp->sysrq) {
 409                         handle_sysrq(c, NULL, hp->tty);
 410                         hp->sysrq = 0;
 411                         continue;
 412                 }
 413 #endif /* CONFIG_MAGIC_SYSRQ */
 414                 tty_insert_flip_char(hp->tty, c, 0);
 415         }
 416 }
 417
 418 /*
 419  * We could get 252 bytes of data at once here. But the tty layer only
 420  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
 421  * it. Accordingly we won't send more than 128 bytes at a time to the flip
 422  * buffer, which will give the tty buffer a chance to throttle us. Should the
 423  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
 424  * revisited.
 425  */
 426 #define TTY_THRESHOLD_THROTTLE 128
 427 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
 428                 const uint8_t *packet)
 429 {
 430         const struct hvsi_header *header = (const struct hvsi_header *)packet;
 431         const uint8_t *data = packet + sizeof(struct hvsi_header);
 432         int datalen = header->len - sizeof(struct hvsi_header);
 433         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
 434
 435         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
 436
 437         if (datalen == 0)
 438                 return NULL;
 439
 440         if (overflow > 0) {
 441                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
 442                 datalen = TTY_THRESHOLD_THROTTLE;
 443         }
 444
 445         hvsi_insert_chars(hp, data, datalen);
 446
 447         if (overflow > 0) {
 448                 /*
 449                  * we still have more data to deliver, so we need to save off the
 450                  * overflow and send it later
 451                  */
 452                 pr_debug("%s: deferring overflow\n", __FUNCTION__);
 453                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
 454                 hp->n_throttle = overflow;
 455         }
 456
 457         return hp->tty;
 458 }
 459
 460 /*
 461  * Returns true/false indicating data successfully read from hypervisor.
 462  * Used both to get packets for tty connections and to advance the state
 463  * machine during console handshaking (in which case tty = NULL and we ignore
 464  * incoming data).
 465  */
 466 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
 467                 struct tty_struct **hangup, struct hvsi_struct **handshake)
 468 {
 469         uint8_t *packet = hp->inbuf;
 470         int chunklen;
 471
 472         *flip = NULL;
 473         *hangup = NULL;
 474         *handshake = NULL;
 475
 476         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
 477         if (chunklen == 0) {
 478                 pr_debug("%s: 0-length read\n", __FUNCTION__);
 479                 return 0;
 480         }
 481
 482         pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
 483         dbg_dump_hex(hp->inbuf_end, chunklen);
 484
 485         hp->inbuf_end += chunklen;
 486
 487         /* handle all completed packets */
 488         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
 489                 struct hvsi_header *header = (struct hvsi_header *)packet;
 490
 491                 if (!is_header(packet)) {
 492                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
 493                         /* skip bytes until we find a header or run out of data */
 494                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
 495                                 packet++;
 496                         continue;
 497                 }
 498
 499                 pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
 500                                 len_packet(packet));
 501                 dbg_dump_packet(packet);
 502
 503                 switch (header->type) {
 504                         case VS_DATA_PACKET_HEADER:
 505                                 if (!is_open(hp))
 506                                         break;
 507                                 if (hp->tty == NULL)
 508                                         break; /* no tty buffer to put data in */
 509                                 *flip = hvsi_recv_data(hp, packet);
 510                                 break;
 511                         case VS_CONTROL_PACKET_HEADER:
 512                                 hvsi_recv_control(hp, packet, hangup, handshake);
 513                                 break;
 514                         case VS_QUERY_RESPONSE_PACKET_HEADER:
 515                                 hvsi_recv_response(hp, packet);
 516                                 break;
 517                         case VS_QUERY_PACKET_HEADER:
 518                                 hvsi_recv_query(hp, packet);
 519                                 break;
 520                         default:
 521                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
 522                                                 hp->index, header->type);
 523                                 dump_packet(packet);
 524                                 break;
 525                 }
 526
 527                 packet += len_packet(packet);
 528
 529                 if (*hangup || *handshake) {
 530                         pr_debug("%s: hangup or handshake\n", __FUNCTION__);
 531                         /*
 532                          * we need to send the hangup now before receiving any more data.
 533                          * If we get "data, hangup, data", we can't deliver the second
 534                          * data before the hangup.
 535                          */
 536                         break;
 537                 }
 538         }
 539
 540         compact_inbuf(hp, packet);
 541
 542         return 1;
 543 }
 544
 545 static void hvsi_send_overflow(struct hvsi_struct *hp)
 546 {
 547         pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
 548                         hp->n_throttle);
 549
 550         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
 551         hp->n_throttle = 0;
 552 }
 553
 554 /*
 555  * must get all pending data because we only get an irq on empty->non-empty
 556  * transition
 557  */
 558 static irqreturn_t hvsi_interrupt(int irq, void *arg, struct pt_regs *regs)
 559 {
 560         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 561         struct tty_struct *flip;
 562         struct tty_struct *hangup;
 563         struct hvsi_struct *handshake;
 564         unsigned long flags;
 565         int again = 1;
 566
 567         pr_debug("%s\n", __FUNCTION__);
 568
 569         while (again) {
 570                 spin_lock_irqsave(&hp->lock, flags);
 571                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
 572                 spin_unlock_irqrestore(&hp->lock, flags);
 573
 574                 /*
 575                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
 576                  * spinlock. But we also have to keep going until we've read all the
 577                  * available data.
 578                  */
 579
 580                 if (flip) {
 581                         /* there was data put in the tty flip buffer */
 582                         tty_flip_buffer_push(flip);
 583                         flip = NULL;
 584                 }
 585
 586                 if (hangup) {
 587                         tty_hangup(hangup);
 588                 }
 589
 590                 if (handshake) {
 591                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
 592                         schedule_work(&handshake->handshaker);
 593                 }
 594         }
 595
 596         spin_lock_irqsave(&hp->lock, flags);
 597         if (hp->tty && hp->n_throttle
 598                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
 599                 /* we weren't hung up and we weren't throttled, so we can deliver the
 600                  * rest now */
 601                 flip = hp->tty;
 602                 hvsi_send_overflow(hp);
 603         }
 604         spin_unlock_irqrestore(&hp->lock, flags);
 605
 606         if (flip) {
 607                 tty_flip_buffer_push(flip);
 608         }
 609
 610         return IRQ_HANDLED;
 611 }
 612
 613 /* for boot console, before the irq handler is running */
 614 static int __init poll_for_state(struct hvsi_struct *hp, int state)
 615 {
 616         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 617
 618         for (;;) {
 619                 hvsi_interrupt(hp->virq, (void *)hp, NULL); /* get pending data */
 620
 621                 if (hp->state == state)
 622                         return 0;
 623
 624                 mdelay(5);
 625                 if (time_after(jiffies, end_jiffies))
 626                         return -EIO;
 627         }
 628 }
 629
 630 /* wait for irq handler to change our state */
 631 static int wait_for_state(struct hvsi_struct *hp, int state)
 632 {
 633         int ret = 0;
 634
 635         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
 636                 ret = -EIO;
 637
 638         return ret;
 639 }
 640
 641 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
 642 {
 643         struct hvsi_query packet __ALIGNED__;
 644         int wrote;
 645
 646         packet.type = VS_QUERY_PACKET_HEADER;
 647         packet.len = sizeof(struct hvsi_query);
 648         packet.seqno = atomic_inc_return(&hp->seqno);
 649         packet.verb = verb;
 650
 651         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
 652         dbg_dump_hex((uint8_t*)&packet, packet.len);
 653
 654         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 655         if (wrote != packet.len) {
 656                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
 657                         wrote);
 658                 return -EIO;
 659         }
 660
 661         return 0;
 662 }
 663
 664 static int hvsi_get_mctrl(struct hvsi_struct *hp)
 665 {
 666         int ret;
 667
 668         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
 669         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
 670
 671         ret = hvsi_wait(hp, HVSI_OPEN);
 672         if (ret < 0) {
 673                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
 674                 set_state(hp, HVSI_OPEN);
 675                 return ret;
 676         }
 677
 678         pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);
 679
 680         return 0;
 681 }
 682
 683 /* note that we can only set DTR */
 684 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
 685 {
 686         struct hvsi_control packet __ALIGNED__;
 687         int wrote;
 688
 689         packet.type = VS_CONTROL_PACKET_HEADER,
 690         packet.seqno = atomic_inc_return(&hp->seqno);
 691         packet.len = sizeof(struct hvsi_control);
 692         packet.verb = VSV_SET_MODEM_CTL;
 693         packet.mask = HVSI_TSDTR;
 694
 695         if (mctrl & TIOCM_DTR)
 696                 packet.word = HVSI_TSDTR;
 697
 698         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
 699         dbg_dump_hex((uint8_t*)&packet, packet.len);
 700
 701         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 702         if (wrote != packet.len) {
 703                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
 704                 return -EIO;
 705         }
 706
 707         return 0;
 708 }
 709
 710 static void hvsi_drain_input(struct hvsi_struct *hp)
 711 {
 712         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
 713         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 714
 715         while (time_before(end_jiffies, jiffies))
 716                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
 717                         break;
 718 }
 719
 720 static int hvsi_handshake(struct hvsi_struct *hp)
 721 {
 722         int ret;
 723
 724         /*
 725          * We could have a CLOSE or other data waiting for us before we even try
 726          * to open; try to throw it all away so we don't get confused. (CLOSE
 727          * is the first message sent up the pipe when the FSP comes online. We
 728          * need to distinguish between "it came up a while ago and we're the first
 729          * user" and "it was just reset before it saw our handshake packet".)
 730          */
 731         hvsi_drain_input(hp);
 732
 733         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
 734         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
 735         if (ret < 0) {
 736                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
 737                 return ret;
 738         }
 739
 740         ret = hvsi_wait(hp, HVSI_OPEN);
 741         if (ret < 0)
 742                 return ret;
 743
 744         return 0;
 745 }
 746
 747 static void hvsi_handshaker(void *arg)
 748 {
 749         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 750
 751         if (hvsi_handshake(hp) >= 0)
 752                 return;
 753
 754         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
 755         if (is_console(hp)) {
 756                 /*
 757                  * ttys will re-attempt the handshake via hvsi_open, but
 758                  * the console will not.
 759                  */
 760                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
 761         }
 762 }
 763
 764 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
 765 {
 766         struct hvsi_data packet __ALIGNED__;
 767         int ret;
 768
 769         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
 770
 771         packet.type = VS_DATA_PACKET_HEADER;
 772         packet.seqno = atomic_inc_return(&hp->seqno);
 773         packet.len = count + sizeof(struct hvsi_header);
 774         memcpy(&packet.data, buf, count);
 775
 776         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 777         if (ret == packet.len) {
 778                 /* return the number of chars written, not the packet length */
 779                 return count;
 780         }
 781         return ret; /* return any errors */
 782 }
 783
 784 static void hvsi_close_protocol(struct hvsi_struct *hp)
 785 {
 786         struct hvsi_control packet __ALIGNED__;
 787
 788         packet.type = VS_CONTROL_PACKET_HEADER;
 789         packet.seqno = atomic_inc_return(&hp->seqno);
 790         packet.len = 6;
 791         packet.verb = VSV_CLOSE_PROTOCOL;
 792
 793         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
 794         dbg_dump_hex((uint8_t*)&packet, packet.len);
 795
 796         hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 797 }
 798
 799 static int hvsi_open(struct tty_struct *tty, struct file *filp)
 800 {
 801         struct hvsi_struct *hp;
 802         unsigned long flags;
 803         int line = tty->index;
 804         int ret;
 805
 806         pr_debug("%s\n", __FUNCTION__);
 807
 808         if (line < 0 || line >= hvsi_count)
 809                 return -ENODEV;
 810         hp = &hvsi_ports[line];
 811
 812         tty->driver_data = hp;
 813         tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
 814
 815         mb();
 816         if (hp->state == HVSI_FSP_DIED)
 817                 return -EIO;
 818
 819         spin_lock_irqsave(&hp->lock, flags);
 820         hp->tty = tty;
 821         hp->count++;
 822         atomic_set(&hp->seqno, 0);
 823         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
 824         spin_unlock_irqrestore(&hp->lock, flags);
 825
 826         if (is_console(hp))
 827                 return 0; /* this has already been handshaked as the console */
 828
 829         ret = hvsi_handshake(hp);
 830         if (ret < 0) {
 831                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
 832                 return ret;
 833         }
 834
 835         ret = hvsi_get_mctrl(hp);
 836         if (ret < 0) {
 837                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
 838                 return ret;
 839         }
 840
 841         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
 842         if (ret < 0) {
 843                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
 844                 return ret;
 845         }
 846
 847         return 0;
 848 }
 849
 850 /* wait for hvsi_write_worker to empty hp->outbuf */
 851 static void hvsi_flush_output(struct hvsi_struct *hp)
 852 {
 853         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
 854
 855         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
 856         cancel_delayed_work(&hp->writer);
 857         flush_scheduled_work();
 858
 859         /*
 860          * it's also possible that our timeout expired and hvsi_write_worker
 861          * didn't manage to push outbuf. poof.
 862          */
 863         hp->n_outbuf = 0;
 864 }
 865
 866 static void hvsi_close(struct tty_struct *tty, struct file *filp)
 867 {
 868         struct hvsi_struct *hp = tty->driver_data;
 869         unsigned long flags;
 870
 871         pr_debug("%s\n", __FUNCTION__);
 872
 873         if (tty_hung_up_p(filp))
 874                 return;
 875
 876         spin_lock_irqsave(&hp->lock, flags);
 877
 878         if (--hp->count == 0) {
 879                 hp->tty = NULL;
 880                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
 881
 882                 /* only close down connection if it is not the console */
 883                 if (!is_console(hp)) {
 884                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
 885                         __set_state(hp, HVSI_CLOSED);
 886                         /*
 887                          * any data delivered to the tty layer after this will be
 888                          * discarded (except for XON/XOFF)
 889                          */
 890                         tty->closing = 1;
 891
 892                         spin_unlock_irqrestore(&hp->lock, flags);
 893
 894                         /* let any existing irq handlers finish. no more will start. */
 895                         synchronize_irq(hp->virq);
 896
 897                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
 898                         hvsi_flush_output(hp);
 899
 900                         /* tell FSP to stop sending data */
 901                         hvsi_close_protocol(hp);
 902
 903                         /*
 904                          * drain anything FSP is still in the middle of sending, and let
 905                          * hvsi_handshake drain the rest on the next open.
 906                          */
 907                         hvsi_drain_input(hp);
 908
 909                         spin_lock_irqsave(&hp->lock, flags);
 910                 }
 911         } else if (hp->count < 0)
 912                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
 913                        hp - hvsi_ports, hp->count);
 914
 915         spin_unlock_irqrestore(&hp->lock, flags);
 916 }
 917
 918 static void hvsi_hangup(struct tty_struct *tty)
 919 {
 920         struct hvsi_struct *hp = tty->driver_data;
 921         unsigned long flags;
 922
 923         pr_debug("%s\n", __FUNCTION__);
 924
 925         spin_lock_irqsave(&hp->lock, flags);
 926
 927         hp->count = 0;
 928         hp->n_outbuf = 0;
 929         hp->tty = NULL;
 930
 931         spin_unlock_irqrestore(&hp->lock, flags);
 932 }
 933
 934 /* called with hp->lock held */
 935 static void hvsi_push(struct hvsi_struct *hp)
 936 {
 937         int n;
 938
 939         if (hp->n_outbuf <= 0)
 940                 return;
 941
 942         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
 943         if (n > 0) {
 944                 /* success */
 945                 pr_debug("%s: wrote %i chars\n", __FUNCTION__, n);
 946                 hp->n_outbuf = 0;
 947         } else if (n == -EIO) {
 948                 __set_state(hp, HVSI_FSP_DIED);
 949                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
 950         }
 951 }
 952
 953 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
 954 static void hvsi_write_worker(void *arg)
 955 {
 956         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 957         unsigned long flags;
 958 #ifdef DEBUG
 959         static long start_j = 0;
 960
 961         if (start_j == 0)
 962                 start_j = jiffies;
 963 #endif /* DEBUG */
 964
 965         spin_lock_irqsave(&hp->lock, flags);
 966
 967         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
 968
 969         if (!is_open(hp)) {
 970                 /*
 971                  * We could have a non-open connection if the service processor died
 972                  * while we were busily scheduling ourselves. In that case, it could
 973                  * be minutes before the service processor comes back, so only try
 974                  * again once a second.
 975                  */
 976                 schedule_delayed_work(&hp->writer, HZ);
 977                 goto out;
 978         }
 979
 980         hvsi_push(hp);
 981         if (hp->n_outbuf > 0)
 982                 schedule_delayed_work(&hp->writer, 10);
 983         else {
 984 #ifdef DEBUG
 985                 pr_debug("%s: outbuf emptied after %li jiffies\n", __FUNCTION__,
 986                                 jiffies - start_j);
 987                 start_j = 0;
 988 #endif /* DEBUG */
 989                 wake_up_all(&hp->emptyq);
 990                 tty_wakeup(hp->tty);
 991         }
 992
 993 out:
 994         spin_unlock_irqrestore(&hp->lock, flags);
 995 }
 996
 997 static int hvsi_write_room(struct tty_struct *tty)
 998 {
 999         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1000
1001         return N_OUTBUF - hp->n_outbuf;
1002 }
1003
1004 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1005 {
1006         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1007
1008         return hp->n_outbuf;
1009 }
1010
1011 static int hvsi_write(struct tty_struct *tty,
1012                      const unsigned char *buf, int count)
1013 {
1014         struct hvsi_struct *hp = tty->driver_data;
1015         const char *source = buf;
1016         unsigned long flags;
1017         int total = 0;
1018         int origcount = count;
1019
1020         spin_lock_irqsave(&hp->lock, flags);
1021
1022         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
1023
1024         if (!is_open(hp)) {
1025                 /* we're either closing or not yet open; don't accept data */
1026                 pr_debug("%s: not open\n", __FUNCTION__);
1027                 goto out;
1028         }
1029
1030         /*
1031          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1032          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1033          * will see there is no room in outbuf and return.
1034          */
1035         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1036                 int chunksize = min(count, hvsi_write_room(hp->tty));
1037
1038                 BUG_ON(hp->n_outbuf < 0);
1039                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1040                 hp->n_outbuf += chunksize;
1041
1042                 total += chunksize;
1043                 source += chunksize;
1044                 count -= chunksize;
1045                 hvsi_push(hp);
1046         }
1047
1048         if (hp->n_outbuf > 0) {
1049                 /*
1050                  * we weren't able to write it all to the hypervisor.
1051                  * schedule another push attempt.
1052                  */
1053                 schedule_delayed_work(&hp->writer, 10);
1054         }
1055
1056 out:
1057         spin_unlock_irqrestore(&hp->lock, flags);
1058
1059         if (total != origcount)
1060                 pr_debug("%s: wanted %i, only wrote %i\n", __FUNCTION__, origcount,
1061                         total);
1062
1063         return total;
1064 }
1065
1066 /*
1067  * I have never seen throttle or unthrottle called, so this little throttle
1068  * buffering scheme may or may not work.
1069  */
1070 static void hvsi_throttle(struct tty_struct *tty)
1071 {
1072         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1073
1074         pr_debug("%s\n", __FUNCTION__);
1075
1076         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1077 }
1078
1079 static void hvsi_unthrottle(struct tty_struct *tty)
1080 {
1081         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1082         unsigned long flags;
1083         int shouldflip = 0;
1084
1085         pr_debug("%s\n", __FUNCTION__);
1086
1087         spin_lock_irqsave(&hp->lock, flags);
1088         if (hp->n_throttle) {
1089                 hvsi_send_overflow(hp);
1090                 shouldflip = 1;
1091         }
1092         spin_unlock_irqrestore(&hp->lock, flags);
1093
1094         if (shouldflip)
1095                 tty_flip_buffer_push(hp->tty);
1096
1097         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1098 }
1099
1100 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1101 {
1102         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1103
1104         hvsi_get_mctrl(hp);
1105         return hp->mctrl;
1106 }
1107
1108 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1109                 unsigned int set, unsigned int clear)
1110 {
1111         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1112         unsigned long flags;
1113         uint16_t new_mctrl;
1114
1115         /* we can only alter DTR */
1116         clear &= TIOCM_DTR;
1117         set &= TIOCM_DTR;
1118
1119         spin_lock_irqsave(&hp->lock, flags);
1120
1121         new_mctrl = (hp->mctrl & ~clear) | set;
1122
1123         if (hp->mctrl != new_mctrl) {
1124                 hvsi_set_mctrl(hp, new_mctrl);
1125                 hp->mctrl = new_mctrl;
1126         }
1127         spin_unlock_irqrestore(&hp->lock, flags);
1128
1129         return 0;
1130 }
1131
1132
1133 static struct tty_operations hvsi_ops = {
1134         .open = hvsi_open,
1135         .close = hvsi_close,
1136         .write = hvsi_write,
1137         .hangup = hvsi_hangup,
1138         .write_room = hvsi_write_room,
1139         .chars_in_buffer = hvsi_chars_in_buffer,
1140         .throttle = hvsi_throttle,
1141         .unthrottle = hvsi_unthrottle,
1142         .tiocmget = hvsi_tiocmget,
1143         .tiocmset = hvsi_tiocmset,
1144 };
1145
1146 static int __init hvsi_init(void)
1147 {
1148         int i;
1149
1150         hvsi_driver = alloc_tty_driver(hvsi_count);
1151         if (!hvsi_driver)
1152                 return -ENOMEM;
1153
1154         hvsi_driver->owner = THIS_MODULE;
1155         hvsi_driver->driver_name = "hvsi";
1156         hvsi_driver->name = "hvsi";
1157         hvsi_driver->major = HVSI_MAJOR;
1158         hvsi_driver->minor_start = HVSI_MINOR;
1159         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1160         hvsi_driver->init_termios = tty_std_termios;
1161         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1162         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1163         tty_set_operations(hvsi_driver, &hvsi_ops);
1164
1165         for (i=0; i < hvsi_count; i++) {
1166                 struct hvsi_struct *hp = &hvsi_ports[i];
1167                 int ret = 1;
1168
1169                 ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp);
1170                 if (ret)
1171                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1172                                 hp->virq, ret);
1173         }
1174         hvsi_wait = wait_for_state; /* irqs active now */
1175
1176         if (tty_register_driver(hvsi_driver))
1177                 panic("Couldn't register hvsi console driver\n");
1178
1179         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1180
1181         return 0;
1182 }
1183 device_initcall(hvsi_init);
1184
1185 /***** console (not tty) code: *****/
1186
1187 static void hvsi_console_print(struct console *console, const char *buf,
1188                 unsigned int count)
1189 {
1190         struct hvsi_struct *hp = &hvsi_ports[console->index];
1191         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1192         unsigned int i = 0, n = 0;
1193         int ret, donecr = 0;
1194
1195         mb();
1196         if (!is_open(hp))
1197                 return;
1198
1199         /*
1200          * ugh, we have to translate LF -> CRLF ourselves, in place.
1201          * copied from hvc_console.c:
1202          */
1203         while (count > 0 || i > 0) {
1204                 if (count > 0 && i < sizeof(c)) {
1205                         if (buf[n] == '\n' && !donecr) {
1206                                 c[i++] = '\r';
1207                                 donecr = 1;
1208                         } else {
1209                                 c[i++] = buf[n++];
1210                                 donecr = 0;
1211                                 --count;
1212                         }
1213                 } else {
1214                         ret = hvsi_put_chars(hp, c, i);
1215                         if (ret < 0)
1216                                 i = 0;
1217                         i -= ret;
1218                 }
1219         }
1220 }
1221
1222 static struct tty_driver *hvsi_console_device(struct console *console,
1223         int *index)
1224 {
1225         *index = console->index;
1226         return hvsi_driver;
1227 }
1228
1229 static int __init hvsi_console_setup(struct console *console, char *options)
1230 {
1231         struct hvsi_struct *hp = &hvsi_ports[console->index];
1232         int ret;
1233
1234         if (console->index < 0 || console->index >= hvsi_count)
1235                 return -1;
1236
1237         /* give the FSP a chance to change the baud rate when we re-open */
1238         hvsi_close_protocol(hp);
1239
1240         ret = hvsi_handshake(hp);
1241         if (ret < 0)
1242                 return ret;
1243
1244         ret = hvsi_get_mctrl(hp);
1245         if (ret < 0)
1246                 return ret;
1247
1248         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1249         if (ret < 0)
1250                 return ret;
1251
1252         hp->flags |= HVSI_CONSOLE;
1253
1254         return 0;
1255 }
1256
1257 static struct console hvsi_con_driver = {
1258         .name           = "hvsi",
1259         .write          = hvsi_console_print,
1260         .device         = hvsi_console_device,
1261         .setup          = hvsi_console_setup,
1262         .flags          = CON_PRINTBUFFER,
1263         .index          = -1,
1264 };
1265
1266 static int __init hvsi_console_init(void)
1267 {
1268         struct device_node *vty;
1269
1270         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1271
1272         /* search device tree for vty nodes */
1273         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1274                         vty != NULL;
1275                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1276                 struct hvsi_struct *hp;
1277                 uint32_t *vtermno;
1278                 uint32_t *irq;
1279
1280                 vtermno = (uint32_t *)get_property(vty, "reg", NULL);
1281                 irq = (uint32_t *)get_property(vty, "interrupts", NULL);
1282                 if (!vtermno || !irq)
1283                         continue;
1284
1285                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1286                         of_node_put(vty);
1287                         break;
1288                 }
1289
1290                 hp = &hvsi_ports[hvsi_count];
1291                 INIT_WORK(&hp->writer, hvsi_write_worker, hp);
1292                 INIT_WORK(&hp->handshaker, hvsi_handshaker, hp);
1293                 init_waitqueue_head(&hp->emptyq);
1294                 init_waitqueue_head(&hp->stateq);
1295                 spin_lock_init(&hp->lock);
1296                 hp->index = hvsi_count;
1297                 hp->inbuf_end = hp->inbuf;
1298                 hp->state = HVSI_CLOSED;
1299                 hp->vtermno = *vtermno;
1300                 hp->virq = irq_create_mapping(NULL, irq[0]);
1301                 if (hp->virq == NO_IRQ) {
1302                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1303                                 __FUNCTION__, irq[0]);
1304                         continue;
1305                 }
1306
1307                 hvsi_count++;
1308         }
1309
1310         if (hvsi_count)
1311                 register_console(&hvsi_con_driver);
1312         return 0;
1313 }
1314 console_initcall(hvsi_console_init);