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 > (sizeof(state_names)/sizeof(char*)))
 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 /* can't use hvc_get_chars because that strips CRs */
 295 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
 296 {
 297         unsigned long got;
 298
 299         if (plpar_hcall(H_GET_TERM_CHAR, hp->vtermno, 0, 0, 0, &got,
 300                         (unsigned long *)buf, (unsigned long *)buf+1) == H_Success)
 301                 return got;
 302         return 0;
 303 }
 304
 305 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
 306         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
 307 {
 308         struct hvsi_control *header = (struct hvsi_control *)packet;
 309
 310         switch (header->verb) {
 311                 case VSV_MODEM_CTL_UPDATE:
 312                         if ((header->word & HVSI_TSCD) == 0) {
 313                                 /* CD went away; no more connection */
 314                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
 315                                 hp->mctrl &= TIOCM_CD;
 316                                 if (!(hp->tty->flags & CLOCAL))
 317                                         *to_hangup = hp->tty;
 318                         }
 319                         break;
 320                 case VSV_CLOSE_PROTOCOL:
 321                         pr_debug("hvsi%i: service processor came back\n", hp->index);
 322                         if (hp->state != HVSI_CLOSED) {
 323                                 *to_handshake = hp;
 324                         }
 325                         break;
 326                 default:
 327                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
 328                                 hp->index);
 329                         dump_packet(packet);
 330                         break;
 331         }
 332 }
 333
 334 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
 335 {
 336         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
 337
 338         switch (hp->state) {
 339                 case HVSI_WAIT_FOR_VER_RESPONSE:
 340                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
 341                         break;
 342                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
 343                         hp->mctrl = 0;
 344                         if (resp->u.mctrl_word & HVSI_TSDTR)
 345                                 hp->mctrl |= TIOCM_DTR;
 346                         if (resp->u.mctrl_word & HVSI_TSCD)
 347                                 hp->mctrl |= TIOCM_CD;
 348                         __set_state(hp, HVSI_OPEN);
 349                         break;
 350                 default:
 351                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
 352                         dump_packet(packet);
 353                         break;
 354         }
 355 }
 356
 357 /* respond to service processor's version query */
 358 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
 359 {
 360         struct hvsi_query_response packet __ALIGNED__;
 361         int wrote;
 362
 363         packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
 364         packet.len = sizeof(struct hvsi_query_response);
 365         packet.seqno = atomic_inc_return(&hp->seqno);
 366         packet.verb = VSV_SEND_VERSION_NUMBER;
 367         packet.u.version = HVSI_VERSION;
 368         packet.query_seqno = query_seqno+1;
 369
 370         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
 371         dbg_dump_hex((uint8_t*)&packet, packet.len);
 372
 373         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 374         if (wrote != packet.len) {
 375                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
 376                         hp->index);
 377                 return -EIO;
 378         }
 379
 380         return 0;
 381 }
 382
 383 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
 384 {
 385         struct hvsi_query *query = (struct hvsi_query *)packet;
 386
 387         switch (hp->state) {
 388                 case HVSI_WAIT_FOR_VER_QUERY:
 389                         hvsi_version_respond(hp, query->seqno);
 390                         __set_state(hp, HVSI_OPEN);
 391                         break;
 392                 default:
 393                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
 394                         dump_packet(packet);
 395                         break;
 396         }
 397 }
 398
 399 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
 400 {
 401         int i;
 402
 403         for (i=0; i < len; i++) {
 404                 char c = buf[i];
 405 #ifdef CONFIG_MAGIC_SYSRQ
 406                 if (c == '\0') {
 407                         hp->sysrq = 1;
 408                         continue;
 409                 } else if (hp->sysrq) {
 410                         handle_sysrq(c, NULL, hp->tty);
 411                         hp->sysrq = 0;
 412                         continue;
 413                 }
 414 #endif /* CONFIG_MAGIC_SYSRQ */
 415                 tty_insert_flip_char(hp->tty, c, 0);
 416         }
 417 }
 418
 419 /*
 420  * We could get 252 bytes of data at once here. But the tty layer only
 421  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
 422  * it. Accordingly we won't send more than 128 bytes at a time to the flip
 423  * buffer, which will give the tty buffer a chance to throttle us. Should the
 424  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
 425  * revisited.
 426  */
 427 #define TTY_THRESHOLD_THROTTLE 128
 428 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
 429                 const uint8_t *packet)
 430 {
 431         const struct hvsi_header *header = (const struct hvsi_header *)packet;
 432         const uint8_t *data = packet + sizeof(struct hvsi_header);
 433         int datalen = header->len - sizeof(struct hvsi_header);
 434         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
 435
 436         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
 437
 438         if (datalen == 0)
 439                 return NULL;
 440
 441         if (overflow > 0) {
 442                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __FUNCTION__);
 443                 datalen = TTY_THRESHOLD_THROTTLE;
 444         }
 445
 446         hvsi_insert_chars(hp, data, datalen);
 447
 448         if (overflow > 0) {
 449                 /*
 450                  * we still have more data to deliver, so we need to save off the
 451                  * overflow and send it later
 452                  */
 453                 pr_debug("%s: deferring overflow\n", __FUNCTION__);
 454                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
 455                 hp->n_throttle = overflow;
 456         }
 457
 458         return hp->tty;
 459 }
 460
 461 /*
 462  * Returns true/false indicating data successfully read from hypervisor.
 463  * Used both to get packets for tty connections and to advance the state
 464  * machine during console handshaking (in which case tty = NULL and we ignore
 465  * incoming data).
 466  */
 467 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
 468                 struct tty_struct **hangup, struct hvsi_struct **handshake)
 469 {
 470         uint8_t *packet = hp->inbuf;
 471         int chunklen;
 472
 473         *flip = NULL;
 474         *hangup = NULL;
 475         *handshake = NULL;
 476
 477         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
 478         if (chunklen == 0) {
 479                 pr_debug("%s: 0-length read\n", __FUNCTION__);
 480                 return 0;
 481         }
 482
 483         pr_debug("%s: got %i bytes\n", __FUNCTION__, chunklen);
 484         dbg_dump_hex(hp->inbuf_end, chunklen);
 485
 486         hp->inbuf_end += chunklen;
 487
 488         /* handle all completed packets */
 489         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
 490                 struct hvsi_header *header = (struct hvsi_header *)packet;
 491
 492                 if (!is_header(packet)) {
 493                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
 494                         /* skip bytes until we find a header or run out of data */
 495                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
 496                                 packet++;
 497                         continue;
 498                 }
 499
 500                 pr_debug("%s: handling %i-byte packet\n", __FUNCTION__,
 501                                 len_packet(packet));
 502                 dbg_dump_packet(packet);
 503
 504                 switch (header->type) {
 505                         case VS_DATA_PACKET_HEADER:
 506                                 if (!is_open(hp))
 507                                         break;
 508                                 if (hp->tty == NULL)
 509                                         break; /* no tty buffer to put data in */
 510                                 *flip = hvsi_recv_data(hp, packet);
 511                                 break;
 512                         case VS_CONTROL_PACKET_HEADER:
 513                                 hvsi_recv_control(hp, packet, hangup, handshake);
 514                                 break;
 515                         case VS_QUERY_RESPONSE_PACKET_HEADER:
 516                                 hvsi_recv_response(hp, packet);
 517                                 break;
 518                         case VS_QUERY_PACKET_HEADER:
 519                                 hvsi_recv_query(hp, packet);
 520                                 break;
 521                         default:
 522                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
 523                                                 hp->index, header->type);
 524                                 dump_packet(packet);
 525                                 break;
 526                 }
 527
 528                 packet += len_packet(packet);
 529
 530                 if (*hangup || *handshake) {
 531                         pr_debug("%s: hangup or handshake\n", __FUNCTION__);
 532                         /*
 533                          * we need to send the hangup now before receiving any more data.
 534                          * If we get "data, hangup, data", we can't deliver the second
 535                          * data before the hangup.
 536                          */
 537                         break;
 538                 }
 539         }
 540
 541         compact_inbuf(hp, packet);
 542
 543         return 1;
 544 }
 545
 546 static void hvsi_send_overflow(struct hvsi_struct *hp)
 547 {
 548         pr_debug("%s: delivering %i bytes overflow\n", __FUNCTION__,
 549                         hp->n_throttle);
 550
 551         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
 552         hp->n_throttle = 0;
 553 }
 554
 555 /*
 556  * must get all pending data because we only get an irq on empty->non-empty
 557  * transition
 558  */
 559 static irqreturn_t hvsi_interrupt(int irq, void *arg, struct pt_regs *regs)
 560 {
 561         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 562         struct tty_struct *flip;
 563         struct tty_struct *hangup;
 564         struct hvsi_struct *handshake;
 565         unsigned long flags;
 566         int again = 1;
 567
 568         pr_debug("%s\n", __FUNCTION__);
 569
 570         while (again) {
 571                 spin_lock_irqsave(&hp->lock, flags);
 572                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
 573                 spin_unlock_irqrestore(&hp->lock, flags);
 574
 575                 /*
 576                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
 577                  * spinlock. But we also have to keep going until we've read all the
 578                  * available data.
 579                  */
 580
 581                 if (flip) {
 582                         /* there was data put in the tty flip buffer */
 583                         tty_flip_buffer_push(flip);
 584                         flip = NULL;
 585                 }
 586
 587                 if (hangup) {
 588                         tty_hangup(hangup);
 589                 }
 590
 591                 if (handshake) {
 592                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
 593                         schedule_work(&handshake->handshaker);
 594                 }
 595         }
 596
 597         spin_lock_irqsave(&hp->lock, flags);
 598         if (hp->tty && hp->n_throttle
 599                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
 600                 /* we weren't hung up and we weren't throttled, so we can deliver the
 601                  * rest now */
 602                 flip = hp->tty;
 603                 hvsi_send_overflow(hp);
 604         }
 605         spin_unlock_irqrestore(&hp->lock, flags);
 606
 607         if (flip) {
 608                 tty_flip_buffer_push(flip);
 609         }
 610
 611         return IRQ_HANDLED;
 612 }
 613
 614 /* for boot console, before the irq handler is running */
 615 static int __init poll_for_state(struct hvsi_struct *hp, int state)
 616 {
 617         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 618
 619         for (;;) {
 620                 hvsi_interrupt(hp->virq, (void *)hp, NULL); /* get pending data */
 621
 622                 if (hp->state == state)
 623                         return 0;
 624
 625                 mdelay(5);
 626                 if (time_after(jiffies, end_jiffies))
 627                         return -EIO;
 628         }
 629 }
 630
 631 /* wait for irq handler to change our state */
 632 static int wait_for_state(struct hvsi_struct *hp, int state)
 633 {
 634         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 635         unsigned long timeout;
 636         int ret = 0;
 637
 638         DECLARE_WAITQUEUE(myself, current);
 639         set_current_state(TASK_INTERRUPTIBLE);
 640         add_wait_queue(&hp->stateq, &myself);
 641
 642         for (;;) {
 643                 set_current_state(TASK_INTERRUPTIBLE);
 644                 if (hp->state == state)
 645                         break;
 646                 timeout = end_jiffies - jiffies;
 647                 if (time_after(jiffies, end_jiffies)) {
 648                         ret = -EIO;
 649                         break;
 650                 }
 651                 schedule_timeout(timeout);
 652         }
 653         remove_wait_queue(&hp->stateq, &myself);
 654         set_current_state(TASK_RUNNING);
 655
 656         return ret;
 657 }
 658
 659 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
 660 {
 661         struct hvsi_query packet __ALIGNED__;
 662         int wrote;
 663
 664         packet.type = VS_QUERY_PACKET_HEADER;
 665         packet.len = sizeof(struct hvsi_query);
 666         packet.seqno = atomic_inc_return(&hp->seqno);
 667         packet.verb = verb;
 668
 669         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
 670         dbg_dump_hex((uint8_t*)&packet, packet.len);
 671
 672         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 673         if (wrote != packet.len) {
 674                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
 675                         wrote);
 676                 return -EIO;
 677         }
 678
 679         return 0;
 680 }
 681
 682 static int hvsi_get_mctrl(struct hvsi_struct *hp)
 683 {
 684         int ret;
 685
 686         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
 687         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
 688
 689         ret = hvsi_wait(hp, HVSI_OPEN);
 690         if (ret < 0) {
 691                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
 692                 set_state(hp, HVSI_OPEN);
 693                 return ret;
 694         }
 695
 696         pr_debug("%s: mctrl 0x%x\n", __FUNCTION__, hp->mctrl);
 697
 698         return 0;
 699 }
 700
 701 /* note that we can only set DTR */
 702 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
 703 {
 704         struct hvsi_control packet __ALIGNED__;
 705         int wrote;
 706
 707         packet.type = VS_CONTROL_PACKET_HEADER,
 708         packet.seqno = atomic_inc_return(&hp->seqno);
 709         packet.len = sizeof(struct hvsi_control);
 710         packet.verb = VSV_SET_MODEM_CTL;
 711         packet.mask = HVSI_TSDTR;
 712
 713         if (mctrl & TIOCM_DTR)
 714                 packet.word = HVSI_TSDTR;
 715
 716         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
 717         dbg_dump_hex((uint8_t*)&packet, packet.len);
 718
 719         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 720         if (wrote != packet.len) {
 721                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
 722                 return -EIO;
 723         }
 724
 725         return 0;
 726 }
 727
 728 static void hvsi_drain_input(struct hvsi_struct *hp)
 729 {
 730         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
 731         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 732
 733         while (time_before(end_jiffies, jiffies))
 734                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
 735                         break;
 736 }
 737
 738 static int hvsi_handshake(struct hvsi_struct *hp)
 739 {
 740         int ret;
 741
 742         /*
 743          * We could have a CLOSE or other data waiting for us before we even try
 744          * to open; try to throw it all away so we don't get confused. (CLOSE
 745          * is the first message sent up the pipe when the FSP comes online. We
 746          * need to distinguish between "it came up a while ago and we're the first
 747          * user" and "it was just reset before it saw our handshake packet".)
 748          */
 749         hvsi_drain_input(hp);
 750
 751         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
 752         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
 753         if (ret < 0) {
 754                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
 755                 return ret;
 756         }
 757
 758         ret = hvsi_wait(hp, HVSI_OPEN);
 759         if (ret < 0)
 760                 return ret;
 761
 762         return 0;
 763 }
 764
 765 static void hvsi_handshaker(void *arg)
 766 {
 767         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 768
 769         if (hvsi_handshake(hp) >= 0)
 770                 return;
 771
 772         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
 773         if (is_console(hp)) {
 774                 /*
 775                  * ttys will re-attempt the handshake via hvsi_open, but
 776                  * the console will not.
 777                  */
 778                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
 779         }
 780 }
 781
 782 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
 783 {
 784         struct hvsi_data packet __ALIGNED__;
 785         int ret;
 786
 787         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
 788
 789         packet.type = VS_DATA_PACKET_HEADER;
 790         packet.seqno = atomic_inc_return(&hp->seqno);
 791         packet.len = count + sizeof(struct hvsi_header);
 792         memcpy(&packet.data, buf, count);
 793
 794         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 795         if (ret == packet.len) {
 796                 /* return the number of chars written, not the packet length */
 797                 return count;
 798         }
 799         return ret; /* return any errors */
 800 }
 801
 802 static void hvsi_close_protocol(struct hvsi_struct *hp)
 803 {
 804         struct hvsi_control packet __ALIGNED__;
 805
 806         packet.type = VS_CONTROL_PACKET_HEADER;
 807         packet.seqno = atomic_inc_return(&hp->seqno);
 808         packet.len = 6;
 809         packet.verb = VSV_CLOSE_PROTOCOL;
 810
 811         pr_debug("%s: sending %i bytes\n", __FUNCTION__, packet.len);
 812         dbg_dump_hex((uint8_t*)&packet, packet.len);
 813
 814         hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 815 }
 816
 817 static int hvsi_open(struct tty_struct *tty, struct file *filp)
 818 {
 819         struct hvsi_struct *hp;
 820         unsigned long flags;
 821         int line = tty->index;
 822         int ret;
 823
 824         pr_debug("%s\n", __FUNCTION__);
 825
 826         if (line < 0 || line >= hvsi_count)
 827                 return -ENODEV;
 828         hp = &hvsi_ports[line];
 829
 830         tty->driver_data = hp;
 831         tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */
 832
 833         mb();
 834         if (hp->state == HVSI_FSP_DIED)
 835                 return -EIO;
 836
 837         spin_lock_irqsave(&hp->lock, flags);
 838         hp->tty = tty;
 839         hp->count++;
 840         atomic_set(&hp->seqno, 0);
 841         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
 842         spin_unlock_irqrestore(&hp->lock, flags);
 843
 844         if (is_console(hp))
 845                 return 0; /* this has already been handshaked as the console */
 846
 847         ret = hvsi_handshake(hp);
 848         if (ret < 0) {
 849                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
 850                 return ret;
 851         }
 852
 853         ret = hvsi_get_mctrl(hp);
 854         if (ret < 0) {
 855                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
 856                 return ret;
 857         }
 858
 859         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
 860         if (ret < 0) {
 861                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
 862                 return ret;
 863         }
 864
 865         return 0;
 866 }
 867
 868 /* wait for hvsi_write_worker to empty hp->outbuf */
 869 static void hvsi_flush_output(struct hvsi_struct *hp)
 870 {
 871         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 872         unsigned long timeout;
 873
 874         DECLARE_WAITQUEUE(myself, current);
 875         set_current_state(TASK_UNINTERRUPTIBLE);
 876         add_wait_queue(&hp->emptyq, &myself);
 877
 878         for (;;) {
 879                 set_current_state(TASK_UNINTERRUPTIBLE);
 880                 if (hp->n_outbuf <= 0)
 881                         break;
 882                 timeout = end_jiffies - jiffies;
 883                 if (time_after(jiffies, end_jiffies))
 884                         break;
 885                 schedule_timeout(timeout);
 886         }
 887         remove_wait_queue(&hp->emptyq, &myself);
 888         set_current_state(TASK_RUNNING);
 889
 890         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
 891         cancel_delayed_work(&hp->writer);
 892         flush_scheduled_work();
 893
 894         /*
 895          * it's also possible that our timeout expired and hvsi_write_worker
 896          * didn't manage to push outbuf. poof.
 897          */
 898         hp->n_outbuf = 0;
 899 }
 900
 901 static void hvsi_close(struct tty_struct *tty, struct file *filp)
 902 {
 903         struct hvsi_struct *hp = tty->driver_data;
 904         unsigned long flags;
 905
 906         pr_debug("%s\n", __FUNCTION__);
 907
 908         if (tty_hung_up_p(filp))
 909                 return;
 910
 911         spin_lock_irqsave(&hp->lock, flags);
 912
 913         if (--hp->count == 0) {
 914                 hp->tty = NULL;
 915                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
 916
 917                 /* only close down connection if it is not the console */
 918                 if (!is_console(hp)) {
 919                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
 920                         __set_state(hp, HVSI_CLOSED);
 921                         /*
 922                          * any data delivered to the tty layer after this will be
 923                          * discarded (except for XON/XOFF)
 924                          */
 925                         tty->closing = 1;
 926
 927                         spin_unlock_irqrestore(&hp->lock, flags);
 928
 929                         /* let any existing irq handlers finish. no more will start. */
 930                         synchronize_irq(hp->virq);
 931
 932                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
 933                         hvsi_flush_output(hp);
 934
 935                         /* tell FSP to stop sending data */
 936                         hvsi_close_protocol(hp);
 937
 938                         /*
 939                          * drain anything FSP is still in the middle of sending, and let
 940                          * hvsi_handshake drain the rest on the next open.
 941                          */
 942                         hvsi_drain_input(hp);
 943
 944                         spin_lock_irqsave(&hp->lock, flags);
 945                 }
 946         } else if (hp->count < 0)
 947                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
 948                        hp - hvsi_ports, hp->count);
 949
 950         spin_unlock_irqrestore(&hp->lock, flags);
 951 }
 952
 953 static void hvsi_hangup(struct tty_struct *tty)
 954 {
 955         struct hvsi_struct *hp = tty->driver_data;
 956         unsigned long flags;
 957
 958         pr_debug("%s\n", __FUNCTION__);
 959
 960         spin_lock_irqsave(&hp->lock, flags);
 961
 962         hp->count = 0;
 963         hp->n_outbuf = 0;
 964         hp->tty = NULL;
 965
 966         spin_unlock_irqrestore(&hp->lock, flags);
 967 }
 968
 969 /* called with hp->lock held */
 970 static void hvsi_push(struct hvsi_struct *hp)
 971 {
 972         int n;
 973
 974         if (hp->n_outbuf <= 0)
 975                 return;
 976
 977         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
 978         if (n > 0) {
 979                 /* success */
 980                 pr_debug("%s: wrote %i chars\n", __FUNCTION__, n);
 981                 hp->n_outbuf = 0;
 982         } else if (n == -EIO) {
 983                 __set_state(hp, HVSI_FSP_DIED);
 984                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
 985         }
 986 }
 987
 988 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
 989 static void hvsi_write_worker(void *arg)
 990 {
 991         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 992         unsigned long flags;
 993 #ifdef DEBUG
 994         static long start_j = 0;
 995
 996         if (start_j == 0)
 997                 start_j = jiffies;
 998 #endif /* DEBUG */
 999
1000         spin_lock_irqsave(&hp->lock, flags);
1001
1002         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
1003
1004         if (!is_open(hp)) {
1005                 /*
1006                  * We could have a non-open connection if the service processor died
1007                  * while we were busily scheduling ourselves. In that case, it could
1008                  * be minutes before the service processor comes back, so only try
1009                  * again once a second.
1010                  */
1011                 schedule_delayed_work(&hp->writer, HZ);
1012                 goto out;
1013         }
1014
1015         hvsi_push(hp);
1016         if (hp->n_outbuf > 0)
1017                 schedule_delayed_work(&hp->writer, 10);
1018         else {
1019 #ifdef DEBUG
1020                 pr_debug("%s: outbuf emptied after %li jiffies\n", __FUNCTION__,
1021                                 jiffies - start_j);
1022                 start_j = 0;
1023 #endif /* DEBUG */
1024                 wake_up_all(&hp->emptyq);
1025                 if (test_bit(TTY_DO_WRITE_WAKEUP, &hp->tty->flags)
1026                                 && hp->tty->ldisc.write_wakeup)
1027                         hp->tty->ldisc.write_wakeup(hp->tty);
1028                 wake_up_interruptible(&hp->tty->write_wait);
1029         }
1030
1031 out:
1032         spin_unlock_irqrestore(&hp->lock, flags);
1033 }
1034
1035 static int hvsi_write_room(struct tty_struct *tty)
1036 {
1037         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1038
1039         return N_OUTBUF - hp->n_outbuf;
1040 }
1041
1042 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1043 {
1044         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1045
1046         return hp->n_outbuf;
1047 }
1048
1049 static int hvsi_write(struct tty_struct *tty,
1050                      const unsigned char *buf, int count)
1051 {
1052         struct hvsi_struct *hp = tty->driver_data;
1053         const char *source = buf;
1054         unsigned long flags;
1055         int total = 0;
1056         int origcount = count;
1057
1058         spin_lock_irqsave(&hp->lock, flags);
1059
1060         pr_debug("%s: %i chars in buffer\n", __FUNCTION__, hp->n_outbuf);
1061
1062         if (!is_open(hp)) {
1063                 /* we're either closing or not yet open; don't accept data */
1064                 pr_debug("%s: not open\n", __FUNCTION__);
1065                 goto out;
1066         }
1067
1068         /*
1069          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1070          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1071          * will see there is no room in outbuf and return.
1072          */
1073         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1074                 int chunksize = min(count, hvsi_write_room(hp->tty));
1075
1076                 BUG_ON(hp->n_outbuf < 0);
1077                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1078                 hp->n_outbuf += chunksize;
1079
1080                 total += chunksize;
1081                 source += chunksize;
1082                 count -= chunksize;
1083                 hvsi_push(hp);
1084         }
1085
1086         if (hp->n_outbuf > 0) {
1087                 /*
1088                  * we weren't able to write it all to the hypervisor.
1089                  * schedule another push attempt.
1090                  */
1091                 schedule_delayed_work(&hp->writer, 10);
1092         }
1093
1094 out:
1095         spin_unlock_irqrestore(&hp->lock, flags);
1096
1097         if (total != origcount)
1098                 pr_debug("%s: wanted %i, only wrote %i\n", __FUNCTION__, origcount,
1099                         total);
1100
1101         return total;
1102 }
1103
1104 /*
1105  * I have never seen throttle or unthrottle called, so this little throttle
1106  * buffering scheme may or may not work.
1107  */
1108 static void hvsi_throttle(struct tty_struct *tty)
1109 {
1110         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1111
1112         pr_debug("%s\n", __FUNCTION__);
1113
1114         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1115 }
1116
1117 static void hvsi_unthrottle(struct tty_struct *tty)
1118 {
1119         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1120         unsigned long flags;
1121         int shouldflip = 0;
1122
1123         pr_debug("%s\n", __FUNCTION__);
1124
1125         spin_lock_irqsave(&hp->lock, flags);
1126         if (hp->n_throttle) {
1127                 hvsi_send_overflow(hp);
1128                 shouldflip = 1;
1129         }
1130         spin_unlock_irqrestore(&hp->lock, flags);
1131
1132         if (shouldflip)
1133                 tty_flip_buffer_push(hp->tty);
1134
1135         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1136 }
1137
1138 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1139 {
1140         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1141
1142         hvsi_get_mctrl(hp);
1143         return hp->mctrl;
1144 }
1145
1146 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1147                 unsigned int set, unsigned int clear)
1148 {
1149         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1150         unsigned long flags;
1151         uint16_t new_mctrl;
1152
1153         /* we can only alter DTR */
1154         clear &= TIOCM_DTR;
1155         set &= TIOCM_DTR;
1156
1157         spin_lock_irqsave(&hp->lock, flags);
1158
1159         new_mctrl = (hp->mctrl & ~clear) | set;
1160
1161         if (hp->mctrl != new_mctrl) {
1162                 hvsi_set_mctrl(hp, new_mctrl);
1163                 hp->mctrl = new_mctrl;
1164         }
1165         spin_unlock_irqrestore(&hp->lock, flags);
1166
1167         return 0;
1168 }
1169
1170
1171 static struct tty_operations hvsi_ops = {
1172         .open = hvsi_open,
1173         .close = hvsi_close,
1174         .write = hvsi_write,
1175         .hangup = hvsi_hangup,
1176         .write_room = hvsi_write_room,
1177         .chars_in_buffer = hvsi_chars_in_buffer,
1178         .throttle = hvsi_throttle,
1179         .unthrottle = hvsi_unthrottle,
1180         .tiocmget = hvsi_tiocmget,
1181         .tiocmset = hvsi_tiocmset,
1182 };
1183
1184 static int __init hvsi_init(void)
1185 {
1186         int i;
1187
1188         hvsi_driver = alloc_tty_driver(hvsi_count);
1189         if (!hvsi_driver)
1190                 return -ENOMEM;
1191
1192         hvsi_driver->owner = THIS_MODULE;
1193         hvsi_driver->devfs_name = "hvsi/";
1194         hvsi_driver->driver_name = "hvsi";
1195         hvsi_driver->name = "hvsi";
1196         hvsi_driver->major = HVSI_MAJOR;
1197         hvsi_driver->minor_start = HVSI_MINOR;
1198         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1199         hvsi_driver->init_termios = tty_std_termios;
1200         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1201         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1202         tty_set_operations(hvsi_driver, &hvsi_ops);
1203
1204         for (i=0; i < hvsi_count; i++) {
1205                 struct hvsi_struct *hp = &hvsi_ports[i];
1206                 int ret = 1;
1207
1208                 ret = request_irq(hp->virq, hvsi_interrupt, SA_INTERRUPT, "hvsi", hp);
1209                 if (ret)
1210                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1211                                 hp->virq, ret);
1212         }
1213         hvsi_wait = wait_for_state; /* irqs active now */
1214
1215         if (tty_register_driver(hvsi_driver))
1216                 panic("Couldn't register hvsi console driver\n");
1217
1218         printk(KERN_INFO "HVSI: registered %i devices\n", hvsi_count);
1219
1220         return 0;
1221 }
1222 device_initcall(hvsi_init);
1223
1224 /***** console (not tty) code: *****/
1225
1226 static void hvsi_console_print(struct console *console, const char *buf,
1227                 unsigned int count)
1228 {
1229         struct hvsi_struct *hp = &hvsi_ports[console->index];
1230         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1231         unsigned int i = 0, n = 0;
1232         int ret, donecr = 0;
1233
1234         mb();
1235         if (!is_open(hp))
1236                 return;
1237
1238         /*
1239          * ugh, we have to translate LF -> CRLF ourselves, in place.
1240          * copied from hvc_console.c:
1241          */
1242         while (count > 0 || i > 0) {
1243                 if (count > 0 && i < sizeof(c)) {
1244                         if (buf[n] == '\n' && !donecr) {
1245                                 c[i++] = '\r';
1246                                 donecr = 1;
1247                         } else {
1248                                 c[i++] = buf[n++];
1249                                 donecr = 0;
1250                                 --count;
1251                         }
1252                 } else {
1253                         ret = hvsi_put_chars(hp, c, i);
1254                         if (ret < 0)
1255                                 i = 0;
1256                         i -= ret;
1257                 }
1258         }
1259 }
1260
1261 static struct tty_driver *hvsi_console_device(struct console *console,
1262         int *index)
1263 {
1264         *index = console->index;
1265         return hvsi_driver;
1266 }
1267
1268 static int __init hvsi_console_setup(struct console *console, char *options)
1269 {
1270         struct hvsi_struct *hp = &hvsi_ports[console->index];
1271         int ret;
1272
1273         if (console->index < 0 || console->index >= hvsi_count)
1274                 return -1;
1275
1276         /* give the FSP a chance to change the baud rate when we re-open */
1277         hvsi_close_protocol(hp);
1278
1279         ret = hvsi_handshake(hp);
1280         if (ret < 0)
1281                 return ret;
1282
1283         ret = hvsi_get_mctrl(hp);
1284         if (ret < 0)
1285                 return ret;
1286
1287         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1288         if (ret < 0)
1289                 return ret;
1290
1291         hp->flags |= HVSI_CONSOLE;
1292
1293         return 0;
1294 }
1295
1296 static struct console hvsi_con_driver = {
1297         .name           = "hvsi",
1298         .write          = hvsi_console_print,
1299         .device         = hvsi_console_device,
1300         .setup          = hvsi_console_setup,
1301         .flags          = CON_PRINTBUFFER,
1302         .index          = -1,
1303 };
1304
1305 static int __init hvsi_console_init(void)
1306 {
1307         struct device_node *vty;
1308
1309         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1310
1311         /* search device tree for vty nodes */
1312         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1313                         vty != NULL;
1314                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1315                 struct hvsi_struct *hp;
1316                 uint32_t *vtermno;
1317                 uint32_t *irq;
1318
1319                 vtermno = (uint32_t *)get_property(vty, "reg", NULL);
1320                 irq = (uint32_t *)get_property(vty, "interrupts", NULL);
1321                 if (!vtermno || !irq)
1322                         continue;
1323
1324                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1325                         of_node_put(vty);
1326                         break;
1327                 }
1328
1329                 hp = &hvsi_ports[hvsi_count];
1330                 INIT_WORK(&hp->writer, hvsi_write_worker, hp);
1331                 INIT_WORK(&hp->handshaker, hvsi_handshaker, hp);
1332                 init_waitqueue_head(&hp->emptyq);
1333                 init_waitqueue_head(&hp->stateq);
1334                 spin_lock_init(&hp->lock);
1335                 hp->index = hvsi_count;
1336                 hp->inbuf_end = hp->inbuf;
1337                 hp->state = HVSI_CLOSED;
1338                 hp->vtermno = *vtermno;
1339                 hp->virq = virt_irq_create_mapping(irq[0]);
1340                 if (hp->virq == NO_IRQ) {
1341                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1342                                 __FUNCTION__, hp->virq);
1343                         continue;
1344                 } else
1345                         hp->virq = irq_offset_up(hp->virq);
1346
1347                 hvsi_count++;
1348         }
1349
1350         if (hvsi_count)
1351                 register_console(&hvsi_con_driver);
1352         return 0;
1353 }
1354 console_initcall(hvsi_console_init);