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/spinlock.h>
  43 #include <linux/sysrq.h>
  44 #include <linux/tty.h>
  45 #include <linux/tty_flip.h>
  46 #include <asm/hvcall.h>
  47 #include <asm/hvconsole.h>
  48 #include <asm/prom.h>
  49 #include <asm/uaccess.h>
  50 #include <asm/vio.h>
  51 #include <asm/param.h>
  52
  53 #define HVSI_MAJOR      229
  54 #define HVSI_MINOR      128
  55 #define MAX_NR_HVSI_CONSOLES 4
  56
  57 #define HVSI_TIMEOUT (5*HZ)
  58 #define HVSI_VERSION 1
  59 #define HVSI_MAX_PACKET 256
  60 #define HVSI_MAX_READ 16
  61 #define HVSI_MAX_OUTGOING_DATA 12
  62 #define N_OUTBUF 12
  63
  64 /*
  65  * we pass data via two 8-byte registers, so we would like our char arrays
  66  * properly aligned for those loads.
  67  */
  68 #define __ALIGNED__     __attribute__((__aligned__(sizeof(long))))
  69
  70 struct hvsi_struct {
  71         struct delayed_work writer;
  72         struct work_struct handshaker;
  73         wait_queue_head_t emptyq; /* woken when outbuf is emptied */
  74         wait_queue_head_t stateq; /* woken when HVSI state changes */
  75         spinlock_t lock;
  76         int index;
  77         struct tty_struct *tty;
  78         unsigned int count;
  79         uint8_t throttle_buf[128];
  80         uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
  81         /* inbuf is for packet reassembly. leave a little room for leftovers. */
  82         uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
  83         uint8_t *inbuf_end;
  84         int n_throttle;
  85         int n_outbuf;
  86         uint32_t vtermno;
  87         uint32_t virq;
  88         atomic_t seqno; /* HVSI packet sequence number */
  89         uint16_t mctrl;
  90         uint8_t state;  /* HVSI protocol state */
  91         uint8_t flags;
  92 #ifdef CONFIG_MAGIC_SYSRQ
  93         uint8_t sysrq;
  94 #endif /* CONFIG_MAGIC_SYSRQ */
  95 };
  96 static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
  97
  98 static struct tty_driver *hvsi_driver;
  99 static int hvsi_count;
 100 static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
 101
 102 enum HVSI_PROTOCOL_STATE {
 103         HVSI_CLOSED,
 104         HVSI_WAIT_FOR_VER_RESPONSE,
 105         HVSI_WAIT_FOR_VER_QUERY,
 106         HVSI_OPEN,
 107         HVSI_WAIT_FOR_MCTRL_RESPONSE,
 108         HVSI_FSP_DIED,
 109 };
 110 #define HVSI_CONSOLE 0x1
 111
 112 #define VS_DATA_PACKET_HEADER           0xff
 113 #define VS_CONTROL_PACKET_HEADER        0xfe
 114 #define VS_QUERY_PACKET_HEADER          0xfd
 115 #define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc
 116
 117 /* control verbs */
 118 #define VSV_SET_MODEM_CTL    1 /* to service processor only */
 119 #define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */
 120 #define VSV_CLOSE_PROTOCOL   3
 121
 122 /* query verbs */
 123 #define VSV_SEND_VERSION_NUMBER 1
 124 #define VSV_SEND_MODEM_CTL_STATUS 2
 125
 126 /* yes, these masks are not consecutive. */
 127 #define HVSI_TSDTR 0x01
 128 #define HVSI_TSCD  0x20
 129
 130 struct hvsi_header {
 131         uint8_t  type;
 132         uint8_t  len;
 133         uint16_t seqno;
 134 } __attribute__((packed));
 135
 136 struct hvsi_data {
 137         uint8_t  type;
 138         uint8_t  len;
 139         uint16_t seqno;
 140         uint8_t  data[HVSI_MAX_OUTGOING_DATA];
 141 } __attribute__((packed));
 142
 143 struct hvsi_control {
 144         uint8_t  type;
 145         uint8_t  len;
 146         uint16_t seqno;
 147         uint16_t verb;
 148         /* optional depending on verb: */
 149         uint32_t word;
 150         uint32_t mask;
 151 } __attribute__((packed));
 152
 153 struct hvsi_query {
 154         uint8_t  type;
 155         uint8_t  len;
 156         uint16_t seqno;
 157         uint16_t verb;
 158 } __attribute__((packed));
 159
 160 struct hvsi_query_response {
 161         uint8_t  type;
 162         uint8_t  len;
 163         uint16_t seqno;
 164         uint16_t verb;
 165         uint16_t query_seqno;
 166         union {
 167                 uint8_t  version;
 168                 uint32_t mctrl_word;
 169         } u;
 170 } __attribute__((packed));
 171
 172
 173
 174 static inline int is_console(struct hvsi_struct *hp)
 175 {
 176         return hp->flags & HVSI_CONSOLE;
 177 }
 178
 179 static inline int is_open(struct hvsi_struct *hp)
 180 {
 181         /* if we're waiting for an mctrl then we're already open */
 182         return (hp->state == HVSI_OPEN)
 183                         || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
 184 }
 185
 186 static inline void print_state(struct hvsi_struct *hp)
 187 {
 188 #ifdef DEBUG
 189         static const char *state_names[] = {
 190                 "HVSI_CLOSED",
 191                 "HVSI_WAIT_FOR_VER_RESPONSE",
 192                 "HVSI_WAIT_FOR_VER_QUERY",
 193                 "HVSI_OPEN",
 194                 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
 195                 "HVSI_FSP_DIED",
 196         };
 197         const char *name = state_names[hp->state];
 198
 199         if (hp->state > ARRAY_SIZE(state_names))
 200                 name = "UNKNOWN";
 201
 202         pr_debug("hvsi%i: state = %s\n", hp->index, name);
 203 #endif /* DEBUG */
 204 }
 205
 206 static inline void __set_state(struct hvsi_struct *hp, int state)
 207 {
 208         hp->state = state;
 209         print_state(hp);
 210         wake_up_all(&hp->stateq);
 211 }
 212
 213 static inline void set_state(struct hvsi_struct *hp, int state)
 214 {
 215         unsigned long flags;
 216
 217         spin_lock_irqsave(&hp->lock, flags);
 218         __set_state(hp, state);
 219         spin_unlock_irqrestore(&hp->lock, flags);
 220 }
 221
 222 static inline int len_packet(const uint8_t *packet)
 223 {
 224         return (int)((struct hvsi_header *)packet)->len;
 225 }
 226
 227 static inline int is_header(const uint8_t *packet)
 228 {
 229         struct hvsi_header *header = (struct hvsi_header *)packet;
 230         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
 231 }
 232
 233 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
 234 {
 235         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
 236                 return 0; /* don't even have the packet header */
 237
 238         if (hp->inbuf_end < (packet + len_packet(packet)))
 239                 return 0; /* don't have the rest of the packet */
 240
 241         return 1;
 242 }
 243
 244 /* shift remaining bytes in packetbuf down */
 245 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
 246 {
 247         int remaining = (int)(hp->inbuf_end - read_to);
 248
 249         pr_debug("%s: %i chars remain\n", __func__, remaining);
 250
 251         if (read_to != hp->inbuf)
 252                 memmove(hp->inbuf, read_to, remaining);
 253
 254         hp->inbuf_end = hp->inbuf + remaining;
 255 }
 256
 257 #ifdef DEBUG
 258 #define dbg_dump_packet(packet) dump_packet(packet)
 259 #define dbg_dump_hex(data, len) dump_hex(data, len)
 260 #else
 261 #define dbg_dump_packet(packet) do { } while (0)
 262 #define dbg_dump_hex(data, len) do { } while (0)
 263 #endif
 264
 265 static void dump_hex(const uint8_t *data, int len)
 266 {
 267         int i;
 268
 269         printk("    ");
 270         for (i=0; i < len; i++)
 271                 printk("%.2x", data[i]);
 272
 273         printk("\n    ");
 274         for (i=0; i < len; i++) {
 275                 if (isprint(data[i]))
 276                         printk("%c", data[i]);
 277                 else
 278                         printk(".");
 279         }
 280         printk("\n");
 281 }
 282
 283 static void dump_packet(uint8_t *packet)
 284 {
 285         struct hvsi_header *header = (struct hvsi_header *)packet;
 286
 287         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
 288                         header->seqno);
 289
 290         dump_hex(packet, header->len);
 291 }
 292
 293 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
 294 {
 295         unsigned long got;
 296
 297         got = hvc_get_chars(hp->vtermno, buf, count);
 298
 299         return got;
 300 }
 301
 302 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
 303         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
 304 {
 305         struct hvsi_control *header = (struct hvsi_control *)packet;
 306
 307         switch (header->verb) {
 308                 case VSV_MODEM_CTL_UPDATE:
 309                         if ((header->word & HVSI_TSCD) == 0) {
 310                                 /* CD went away; no more connection */
 311                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
 312                                 hp->mctrl &= TIOCM_CD;
 313                                 /* If userland hasn't done an open(2) yet, hp->tty is NULL. */
 314                                 if (hp->tty && !(hp->tty->flags & CLOCAL))
 315                                         *to_hangup = hp->tty;
 316                         }
 317                         break;
 318                 case VSV_CLOSE_PROTOCOL:
 319                         pr_debug("hvsi%i: service processor came back\n", hp->index);
 320                         if (hp->state != HVSI_CLOSED) {
 321                                 *to_handshake = hp;
 322                         }
 323                         break;
 324                 default:
 325                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
 326                                 hp->index);
 327                         dump_packet(packet);
 328                         break;
 329         }
 330 }
 331
 332 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
 333 {
 334         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
 335
 336         switch (hp->state) {
 337                 case HVSI_WAIT_FOR_VER_RESPONSE:
 338                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
 339                         break;
 340                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
 341                         hp->mctrl = 0;
 342                         if (resp->u.mctrl_word & HVSI_TSDTR)
 343                                 hp->mctrl |= TIOCM_DTR;
 344                         if (resp->u.mctrl_word & HVSI_TSCD)
 345                                 hp->mctrl |= TIOCM_CD;
 346                         __set_state(hp, HVSI_OPEN);
 347                         break;
 348                 default:
 349                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
 350                         dump_packet(packet);
 351                         break;
 352         }
 353 }
 354
 355 /* respond to service processor's version query */
 356 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
 357 {
 358         struct hvsi_query_response packet __ALIGNED__;
 359         int wrote;
 360
 361         packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
 362         packet.len = sizeof(struct hvsi_query_response);
 363         packet.seqno = atomic_inc_return(&hp->seqno);
 364         packet.verb = VSV_SEND_VERSION_NUMBER;
 365         packet.u.version = HVSI_VERSION;
 366         packet.query_seqno = query_seqno+1;
 367
 368         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
 369         dbg_dump_hex((uint8_t*)&packet, packet.len);
 370
 371         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 372         if (wrote != packet.len) {
 373                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
 374                         hp->index);
 375                 return -EIO;
 376         }
 377
 378         return 0;
 379 }
 380
 381 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
 382 {
 383         struct hvsi_query *query = (struct hvsi_query *)packet;
 384
 385         switch (hp->state) {
 386                 case HVSI_WAIT_FOR_VER_QUERY:
 387                         hvsi_version_respond(hp, query->seqno);
 388                         __set_state(hp, HVSI_OPEN);
 389                         break;
 390                 default:
 391                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
 392                         dump_packet(packet);
 393                         break;
 394         }
 395 }
 396
 397 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
 398 {
 399         int i;
 400
 401         for (i=0; i < len; i++) {
 402                 char c = buf[i];
 403 #ifdef CONFIG_MAGIC_SYSRQ
 404                 if (c == '\0') {
 405                         hp->sysrq = 1;
 406                         continue;
 407                 } else if (hp->sysrq) {
 408                         handle_sysrq(c, hp->tty);
 409                         hp->sysrq = 0;
 410                         continue;
 411                 }
 412 #endif /* CONFIG_MAGIC_SYSRQ */
 413                 tty_insert_flip_char(hp->tty, c, 0);
 414         }
 415 }
 416
 417 /*
 418  * We could get 252 bytes of data at once here. But the tty layer only
 419  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
 420  * it. Accordingly we won't send more than 128 bytes at a time to the flip
 421  * buffer, which will give the tty buffer a chance to throttle us. Should the
 422  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
 423  * revisited.
 424  */
 425 #define TTY_THRESHOLD_THROTTLE 128
 426 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
 427                 const uint8_t *packet)
 428 {
 429         const struct hvsi_header *header = (const struct hvsi_header *)packet;
 430         const uint8_t *data = packet + sizeof(struct hvsi_header);
 431         int datalen = header->len - sizeof(struct hvsi_header);
 432         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
 433
 434         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
 435
 436         if (datalen == 0)
 437                 return NULL;
 438
 439         if (overflow > 0) {
 440                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
 441                 datalen = TTY_THRESHOLD_THROTTLE;
 442         }
 443
 444         hvsi_insert_chars(hp, data, datalen);
 445
 446         if (overflow > 0) {
 447                 /*
 448                  * we still have more data to deliver, so we need to save off the
 449                  * overflow and send it later
 450                  */
 451                 pr_debug("%s: deferring overflow\n", __func__);
 452                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
 453                 hp->n_throttle = overflow;
 454         }
 455
 456         return hp->tty;
 457 }
 458
 459 /*
 460  * Returns true/false indicating data successfully read from hypervisor.
 461  * Used both to get packets for tty connections and to advance the state
 462  * machine during console handshaking (in which case tty = NULL and we ignore
 463  * incoming data).
 464  */
 465 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
 466                 struct tty_struct **hangup, struct hvsi_struct **handshake)
 467 {
 468         uint8_t *packet = hp->inbuf;
 469         int chunklen;
 470
 471         *flip = NULL;
 472         *hangup = NULL;
 473         *handshake = NULL;
 474
 475         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
 476         if (chunklen == 0) {
 477                 pr_debug("%s: 0-length read\n", __func__);
 478                 return 0;
 479         }
 480
 481         pr_debug("%s: got %i bytes\n", __func__, chunklen);
 482         dbg_dump_hex(hp->inbuf_end, chunklen);
 483
 484         hp->inbuf_end += chunklen;
 485
 486         /* handle all completed packets */
 487         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
 488                 struct hvsi_header *header = (struct hvsi_header *)packet;
 489
 490                 if (!is_header(packet)) {
 491                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
 492                         /* skip bytes until we find a header or run out of data */
 493                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
 494                                 packet++;
 495                         continue;
 496                 }
 497
 498                 pr_debug("%s: handling %i-byte packet\n", __func__,
 499                                 len_packet(packet));
 500                 dbg_dump_packet(packet);
 501
 502                 switch (header->type) {
 503                         case VS_DATA_PACKET_HEADER:
 504                                 if (!is_open(hp))
 505                                         break;
 506                                 if (hp->tty == NULL)
 507                                         break; /* no tty buffer to put data in */
 508                                 *flip = hvsi_recv_data(hp, packet);
 509                                 break;
 510                         case VS_CONTROL_PACKET_HEADER:
 511                                 hvsi_recv_control(hp, packet, hangup, handshake);
 512                                 break;
 513                         case VS_QUERY_RESPONSE_PACKET_HEADER:
 514                                 hvsi_recv_response(hp, packet);
 515                                 break;
 516                         case VS_QUERY_PACKET_HEADER:
 517                                 hvsi_recv_query(hp, packet);
 518                                 break;
 519                         default:
 520                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
 521                                                 hp->index, header->type);
 522                                 dump_packet(packet);
 523                                 break;
 524                 }
 525
 526                 packet += len_packet(packet);
 527
 528                 if (*hangup || *handshake) {
 529                         pr_debug("%s: hangup or handshake\n", __func__);
 530                         /*
 531                          * we need to send the hangup now before receiving any more data.
 532                          * If we get "data, hangup, data", we can't deliver the second
 533                          * data before the hangup.
 534                          */
 535                         break;
 536                 }
 537         }
 538
 539         compact_inbuf(hp, packet);
 540
 541         return 1;
 542 }
 543
 544 static void hvsi_send_overflow(struct hvsi_struct *hp)
 545 {
 546         pr_debug("%s: delivering %i bytes overflow\n", __func__,
 547                         hp->n_throttle);
 548
 549         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
 550         hp->n_throttle = 0;
 551 }
 552
 553 /*
 554  * must get all pending data because we only get an irq on empty->non-empty
 555  * transition
 556  */
 557 static irqreturn_t hvsi_interrupt(int irq, void *arg)
 558 {
 559         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 560         struct tty_struct *flip;
 561         struct tty_struct *hangup;
 562         struct hvsi_struct *handshake;
 563         unsigned long flags;
 564         int again = 1;
 565
 566         pr_debug("%s\n", __func__);
 567
 568         while (again) {
 569                 spin_lock_irqsave(&hp->lock, flags);
 570                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
 571                 spin_unlock_irqrestore(&hp->lock, flags);
 572
 573                 /*
 574                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
 575                  * spinlock. But we also have to keep going until we've read all the
 576                  * available data.
 577                  */
 578
 579                 if (flip) {
 580                         /* there was data put in the tty flip buffer */
 581                         tty_flip_buffer_push(flip);
 582                         flip = NULL;
 583                 }
 584
 585                 if (hangup) {
 586                         tty_hangup(hangup);
 587                 }
 588
 589                 if (handshake) {
 590                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
 591                         schedule_work(&handshake->handshaker);
 592                 }
 593         }
 594
 595         spin_lock_irqsave(&hp->lock, flags);
 596         if (hp->tty && hp->n_throttle
 597                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
 598                 /* we weren't hung up and we weren't throttled, so we can deliver the
 599                  * rest now */
 600                 flip = hp->tty;
 601                 hvsi_send_overflow(hp);
 602         }
 603         spin_unlock_irqrestore(&hp->lock, flags);
 604
 605         if (flip) {
 606                 tty_flip_buffer_push(flip);
 607         }
 608
 609         return IRQ_HANDLED;
 610 }
 611
 612 /* for boot console, before the irq handler is running */
 613 static int __init poll_for_state(struct hvsi_struct *hp, int state)
 614 {
 615         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 616
 617         for (;;) {
 618                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
 619
 620                 if (hp->state == state)
 621                         return 0;
 622
 623                 mdelay(5);
 624                 if (time_after(jiffies, end_jiffies))
 625                         return -EIO;
 626         }
 627 }
 628
 629 /* wait for irq handler to change our state */
 630 static int wait_for_state(struct hvsi_struct *hp, int state)
 631 {
 632         int ret = 0;
 633
 634         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
 635                 ret = -EIO;
 636
 637         return ret;
 638 }
 639
 640 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
 641 {
 642         struct hvsi_query packet __ALIGNED__;
 643         int wrote;
 644
 645         packet.type = VS_QUERY_PACKET_HEADER;
 646         packet.len = sizeof(struct hvsi_query);
 647         packet.seqno = atomic_inc_return(&hp->seqno);
 648         packet.verb = verb;
 649
 650         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
 651         dbg_dump_hex((uint8_t*)&packet, packet.len);
 652
 653         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 654         if (wrote != packet.len) {
 655                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
 656                         wrote);
 657                 return -EIO;
 658         }
 659
 660         return 0;
 661 }
 662
 663 static int hvsi_get_mctrl(struct hvsi_struct *hp)
 664 {
 665         int ret;
 666
 667         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
 668         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
 669
 670         ret = hvsi_wait(hp, HVSI_OPEN);
 671         if (ret < 0) {
 672                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
 673                 set_state(hp, HVSI_OPEN);
 674                 return ret;
 675         }
 676
 677         pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
 678
 679         return 0;
 680 }
 681
 682 /* note that we can only set DTR */
 683 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
 684 {
 685         struct hvsi_control packet __ALIGNED__;
 686         int wrote;
 687
 688         packet.type = VS_CONTROL_PACKET_HEADER,
 689         packet.seqno = atomic_inc_return(&hp->seqno);
 690         packet.len = sizeof(struct hvsi_control);
 691         packet.verb = VSV_SET_MODEM_CTL;
 692         packet.mask = HVSI_TSDTR;
 693
 694         if (mctrl & TIOCM_DTR)
 695                 packet.word = HVSI_TSDTR;
 696
 697         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
 698         dbg_dump_hex((uint8_t*)&packet, packet.len);
 699
 700         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 701         if (wrote != packet.len) {
 702                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
 703                 return -EIO;
 704         }
 705
 706         return 0;
 707 }
 708
 709 static void hvsi_drain_input(struct hvsi_struct *hp)
 710 {
 711         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
 712         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 713
 714         while (time_before(end_jiffies, jiffies))
 715                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
 716                         break;
 717 }
 718
 719 static int hvsi_handshake(struct hvsi_struct *hp)
 720 {
 721         int ret;
 722
 723         /*
 724          * We could have a CLOSE or other data waiting for us before we even try
 725          * to open; try to throw it all away so we don't get confused. (CLOSE
 726          * is the first message sent up the pipe when the FSP comes online. We
 727          * need to distinguish between "it came up a while ago and we're the first
 728          * user" and "it was just reset before it saw our handshake packet".)
 729          */
 730         hvsi_drain_input(hp);
 731
 732         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
 733         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
 734         if (ret < 0) {
 735                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
 736                 return ret;
 737         }
 738
 739         ret = hvsi_wait(hp, HVSI_OPEN);
 740         if (ret < 0)
 741                 return ret;
 742
 743         return 0;
 744 }
 745
 746 static void hvsi_handshaker(struct work_struct *work)
 747 {
 748         struct hvsi_struct *hp =
 749                 container_of(work, struct hvsi_struct, handshaker);
 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", __func__, 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", __func__);
 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", __func__);
 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", __func__);
 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", __func__, 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(struct work_struct *work)
 955 {
 956         struct hvsi_struct *hp =
 957                 container_of(work, struct hvsi_struct, writer.work);
 958         unsigned long flags;
 959 #ifdef DEBUG
 960         static long start_j = 0;
 961
 962         if (start_j == 0)
 963                 start_j = jiffies;
 964 #endif /* DEBUG */
 965
 966         spin_lock_irqsave(&hp->lock, flags);
 967
 968         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
 969
 970         if (!is_open(hp)) {
 971                 /*
 972                  * We could have a non-open connection if the service processor died
 973                  * while we were busily scheduling ourselves. In that case, it could
 974                  * be minutes before the service processor comes back, so only try
 975                  * again once a second.
 976                  */
 977                 schedule_delayed_work(&hp->writer, HZ);
 978                 goto out;
 979         }
 980
 981         hvsi_push(hp);
 982         if (hp->n_outbuf > 0)
 983                 schedule_delayed_work(&hp->writer, 10);
 984         else {
 985 #ifdef DEBUG
 986                 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
 987                                 jiffies - start_j);
 988                 start_j = 0;
 989 #endif /* DEBUG */
 990                 wake_up_all(&hp->emptyq);
 991                 tty_wakeup(hp->tty);
 992         }
 993
 994 out:
 995         spin_unlock_irqrestore(&hp->lock, flags);
 996 }
 997
 998 static int hvsi_write_room(struct tty_struct *tty)
 999 {
1000         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1001
1002         return N_OUTBUF - hp->n_outbuf;
1003 }
1004
1005 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1006 {
1007         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1008
1009         return hp->n_outbuf;
1010 }
1011
1012 static int hvsi_write(struct tty_struct *tty,
1013                      const unsigned char *buf, int count)
1014 {
1015         struct hvsi_struct *hp = tty->driver_data;
1016         const char *source = buf;
1017         unsigned long flags;
1018         int total = 0;
1019         int origcount = count;
1020
1021         spin_lock_irqsave(&hp->lock, flags);
1022
1023         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
1024
1025         if (!is_open(hp)) {
1026                 /* we're either closing or not yet open; don't accept data */
1027                 pr_debug("%s: not open\n", __func__);
1028                 goto out;
1029         }
1030
1031         /*
1032          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1033          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1034          * will see there is no room in outbuf and return.
1035          */
1036         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1037                 int chunksize = min(count, hvsi_write_room(hp->tty));
1038
1039                 BUG_ON(hp->n_outbuf < 0);
1040                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1041                 hp->n_outbuf += chunksize;
1042
1043                 total += chunksize;
1044                 source += chunksize;
1045                 count -= chunksize;
1046                 hvsi_push(hp);
1047         }
1048
1049         if (hp->n_outbuf > 0) {
1050                 /*
1051                  * we weren't able to write it all to the hypervisor.
1052                  * schedule another push attempt.
1053                  */
1054                 schedule_delayed_work(&hp->writer, 10);
1055         }
1056
1057 out:
1058         spin_unlock_irqrestore(&hp->lock, flags);
1059
1060         if (total != origcount)
1061                 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
1062                         total);
1063
1064         return total;
1065 }
1066
1067 /*
1068  * I have never seen throttle or unthrottle called, so this little throttle
1069  * buffering scheme may or may not work.
1070  */
1071 static void hvsi_throttle(struct tty_struct *tty)
1072 {
1073         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1074
1075         pr_debug("%s\n", __func__);
1076
1077         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1078 }
1079
1080 static void hvsi_unthrottle(struct tty_struct *tty)
1081 {
1082         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1083         unsigned long flags;
1084         int shouldflip = 0;
1085
1086         pr_debug("%s\n", __func__);
1087
1088         spin_lock_irqsave(&hp->lock, flags);
1089         if (hp->n_throttle) {
1090                 hvsi_send_overflow(hp);
1091                 shouldflip = 1;
1092         }
1093         spin_unlock_irqrestore(&hp->lock, flags);
1094
1095         if (shouldflip)
1096                 tty_flip_buffer_push(hp->tty);
1097
1098         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1099 }
1100
1101 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1102 {
1103         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1104
1105         hvsi_get_mctrl(hp);
1106         return hp->mctrl;
1107 }
1108
1109 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1110                 unsigned int set, unsigned int clear)
1111 {
1112         struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data;
1113         unsigned long flags;
1114         uint16_t new_mctrl;
1115
1116         /* we can only alter DTR */
1117         clear &= TIOCM_DTR;
1118         set &= TIOCM_DTR;
1119
1120         spin_lock_irqsave(&hp->lock, flags);
1121
1122         new_mctrl = (hp->mctrl & ~clear) | set;
1123
1124         if (hp->mctrl != new_mctrl) {
1125                 hvsi_set_mctrl(hp, new_mctrl);
1126                 hp->mctrl = new_mctrl;
1127         }
1128         spin_unlock_irqrestore(&hp->lock, flags);
1129
1130         return 0;
1131 }
1132
1133
1134 static const struct tty_operations hvsi_ops = {
1135         .open = hvsi_open,
1136         .close = hvsi_close,
1137         .write = hvsi_write,
1138         .hangup = hvsi_hangup,
1139         .write_room = hvsi_write_room,
1140         .chars_in_buffer = hvsi_chars_in_buffer,
1141         .throttle = hvsi_throttle,
1142         .unthrottle = hvsi_unthrottle,
1143         .tiocmget = hvsi_tiocmget,
1144         .tiocmset = hvsi_tiocmset,
1145 };
1146
1147 static int __init hvsi_init(void)
1148 {
1149         int i;
1150
1151         hvsi_driver = alloc_tty_driver(hvsi_count);
1152         if (!hvsi_driver)
1153                 return -ENOMEM;
1154
1155         hvsi_driver->owner = THIS_MODULE;
1156         hvsi_driver->driver_name = "hvsi";
1157         hvsi_driver->name = "hvsi";
1158         hvsi_driver->major = HVSI_MAJOR;
1159         hvsi_driver->minor_start = HVSI_MINOR;
1160         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1161         hvsi_driver->init_termios = tty_std_termios;
1162         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1163         hvsi_driver->init_termios.c_ispeed = 9600;
1164         hvsi_driver->init_termios.c_ospeed = 9600;
1165         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1166         tty_set_operations(hvsi_driver, &hvsi_ops);
1167
1168         for (i=0; i < hvsi_count; i++) {
1169                 struct hvsi_struct *hp = &hvsi_ports[i];
1170                 int ret = 1;
1171
1172                 ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp);
1173                 if (ret)
1174                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1175                                 hp->virq, ret);
1176         }
1177         hvsi_wait = wait_for_state; /* irqs active now */
1178
1179         if (tty_register_driver(hvsi_driver))
1180                 panic("Couldn't register hvsi console driver\n");
1181
1182         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1183
1184         return 0;
1185 }
1186 device_initcall(hvsi_init);
1187
1188 /***** console (not tty) code: *****/
1189
1190 static void hvsi_console_print(struct console *console, const char *buf,
1191                 unsigned int count)
1192 {
1193         struct hvsi_struct *hp = &hvsi_ports[console->index];
1194         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1195         unsigned int i = 0, n = 0;
1196         int ret, donecr = 0;
1197
1198         mb();
1199         if (!is_open(hp))
1200                 return;
1201
1202         /*
1203          * ugh, we have to translate LF -> CRLF ourselves, in place.
1204          * copied from hvc_console.c:
1205          */
1206         while (count > 0 || i > 0) {
1207                 if (count > 0 && i < sizeof(c)) {
1208                         if (buf[n] == '\n' && !donecr) {
1209                                 c[i++] = '\r';
1210                                 donecr = 1;
1211                         } else {
1212                                 c[i++] = buf[n++];
1213                                 donecr = 0;
1214                                 --count;
1215                         }
1216                 } else {
1217                         ret = hvsi_put_chars(hp, c, i);
1218                         if (ret < 0)
1219                                 i = 0;
1220                         i -= ret;
1221                 }
1222         }
1223 }
1224
1225 static struct tty_driver *hvsi_console_device(struct console *console,
1226         int *index)
1227 {
1228         *index = console->index;
1229         return hvsi_driver;
1230 }
1231
1232 static int __init hvsi_console_setup(struct console *console, char *options)
1233 {
1234         struct hvsi_struct *hp = &hvsi_ports[console->index];
1235         int ret;
1236
1237         if (console->index < 0 || console->index >= hvsi_count)
1238                 return -1;
1239
1240         /* give the FSP a chance to change the baud rate when we re-open */
1241         hvsi_close_protocol(hp);
1242
1243         ret = hvsi_handshake(hp);
1244         if (ret < 0)
1245                 return ret;
1246
1247         ret = hvsi_get_mctrl(hp);
1248         if (ret < 0)
1249                 return ret;
1250
1251         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1252         if (ret < 0)
1253                 return ret;
1254
1255         hp->flags |= HVSI_CONSOLE;
1256
1257         return 0;
1258 }
1259
1260 static struct console hvsi_con_driver = {
1261         .name           = "hvsi",
1262         .write          = hvsi_console_print,
1263         .device         = hvsi_console_device,
1264         .setup          = hvsi_console_setup,
1265         .flags          = CON_PRINTBUFFER,
1266         .index          = -1,
1267 };
1268
1269 static int __init hvsi_console_init(void)
1270 {
1271         struct device_node *vty;
1272
1273         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1274
1275         /* search device tree for vty nodes */
1276         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1277                         vty != NULL;
1278                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1279                 struct hvsi_struct *hp;
1280                 const uint32_t *vtermno, *irq;
1281
1282                 vtermno = of_get_property(vty, "reg", NULL);
1283                 irq = of_get_property(vty, "interrupts", NULL);
1284                 if (!vtermno || !irq)
1285                         continue;
1286
1287                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1288                         of_node_put(vty);
1289                         break;
1290                 }
1291
1292                 hp = &hvsi_ports[hvsi_count];
1293                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1294                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1295                 init_waitqueue_head(&hp->emptyq);
1296                 init_waitqueue_head(&hp->stateq);
1297                 spin_lock_init(&hp->lock);
1298                 hp->index = hvsi_count;
1299                 hp->inbuf_end = hp->inbuf;
1300                 hp->state = HVSI_CLOSED;
1301                 hp->vtermno = *vtermno;
1302                 hp->virq = irq_create_mapping(NULL, irq[0]);
1303                 if (hp->virq == NO_IRQ) {
1304                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1305                                 __func__, irq[0]);
1306                         continue;
1307                 }
1308
1309                 hvsi_count++;
1310         }
1311
1312         if (hvsi_count)
1313                 register_console(&hvsi_con_driver);
1314         return 0;
1315 }
1316 console_initcall(hvsi_console_init);