drivers/tty/hvc/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 #include <asm/hvsi.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 tty_port port;
  73         struct delayed_work writer;
  74         struct work_struct handshaker;
  75         wait_queue_head_t emptyq; /* woken when outbuf is emptied */
  76         wait_queue_head_t stateq; /* woken when HVSI state changes */
  77         spinlock_t lock;
  78         int index;
  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 static inline int is_console(struct hvsi_struct *hp)
 113 {
 114         return hp->flags & HVSI_CONSOLE;
 115 }
 116
 117 static inline int is_open(struct hvsi_struct *hp)
 118 {
 119         /* if we're waiting for an mctrl then we're already open */
 120         return (hp->state == HVSI_OPEN)
 121                         || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
 122 }
 123
 124 static inline void print_state(struct hvsi_struct *hp)
 125 {
 126 #ifdef DEBUG
 127         static const char *state_names[] = {
 128                 "HVSI_CLOSED",
 129                 "HVSI_WAIT_FOR_VER_RESPONSE",
 130                 "HVSI_WAIT_FOR_VER_QUERY",
 131                 "HVSI_OPEN",
 132                 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
 133                 "HVSI_FSP_DIED",
 134         };
 135         const char *name = (hp->state < ARRAY_SIZE(state_names))
 136                 ? state_names[hp->state] : "UNKNOWN";
 137
 138         pr_debug("hvsi%i: state = %s\n", hp->index, name);
 139 #endif /* DEBUG */
 140 }
 141
 142 static inline void __set_state(struct hvsi_struct *hp, int state)
 143 {
 144         hp->state = state;
 145         print_state(hp);
 146         wake_up_all(&hp->stateq);
 147 }
 148
 149 static inline void set_state(struct hvsi_struct *hp, int state)
 150 {
 151         unsigned long flags;
 152
 153         spin_lock_irqsave(&hp->lock, flags);
 154         __set_state(hp, state);
 155         spin_unlock_irqrestore(&hp->lock, flags);
 156 }
 157
 158 static inline int len_packet(const uint8_t *packet)
 159 {
 160         return (int)((struct hvsi_header *)packet)->len;
 161 }
 162
 163 static inline int is_header(const uint8_t *packet)
 164 {
 165         struct hvsi_header *header = (struct hvsi_header *)packet;
 166         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
 167 }
 168
 169 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
 170 {
 171         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
 172                 return 0; /* don't even have the packet header */
 173
 174         if (hp->inbuf_end < (packet + len_packet(packet)))
 175                 return 0; /* don't have the rest of the packet */
 176
 177         return 1;
 178 }
 179
 180 /* shift remaining bytes in packetbuf down */
 181 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
 182 {
 183         int remaining = (int)(hp->inbuf_end - read_to);
 184
 185         pr_debug("%s: %i chars remain\n", __func__, remaining);
 186
 187         if (read_to != hp->inbuf)
 188                 memmove(hp->inbuf, read_to, remaining);
 189
 190         hp->inbuf_end = hp->inbuf + remaining;
 191 }
 192
 193 #ifdef DEBUG
 194 #define dbg_dump_packet(packet) dump_packet(packet)
 195 #define dbg_dump_hex(data, len) dump_hex(data, len)
 196 #else
 197 #define dbg_dump_packet(packet) do { } while (0)
 198 #define dbg_dump_hex(data, len) do { } while (0)
 199 #endif
 200
 201 static void dump_hex(const uint8_t *data, int len)
 202 {
 203         int i;
 204
 205         printk("    ");
 206         for (i=0; i < len; i++)
 207                 printk("%.2x", data[i]);
 208
 209         printk("\n    ");
 210         for (i=0; i < len; i++) {
 211                 if (isprint(data[i]))
 212                         printk("%c", data[i]);
 213                 else
 214                         printk(".");
 215         }
 216         printk("\n");
 217 }
 218
 219 static void dump_packet(uint8_t *packet)
 220 {
 221         struct hvsi_header *header = (struct hvsi_header *)packet;
 222
 223         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
 224                         header->seqno);
 225
 226         dump_hex(packet, header->len);
 227 }
 228
 229 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
 230 {
 231         unsigned long got;
 232
 233         got = hvc_get_chars(hp->vtermno, buf, count);
 234
 235         return got;
 236 }
 237
 238 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
 239         struct tty_struct *tty, struct hvsi_struct **to_handshake)
 240 {
 241         struct hvsi_control *header = (struct hvsi_control *)packet;
 242
 243         switch (header->verb) {
 244                 case VSV_MODEM_CTL_UPDATE:
 245                         if ((header->word & HVSI_TSCD) == 0) {
 246                                 /* CD went away; no more connection */
 247                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
 248                                 hp->mctrl &= TIOCM_CD;
 249                                 if (tty && !C_CLOCAL(tty))
 250                                         tty_hangup(tty);
 251                         }
 252                         break;
 253                 case VSV_CLOSE_PROTOCOL:
 254                         pr_debug("hvsi%i: service processor came back\n", hp->index);
 255                         if (hp->state != HVSI_CLOSED) {
 256                                 *to_handshake = hp;
 257                         }
 258                         break;
 259                 default:
 260                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
 261                                 hp->index);
 262                         dump_packet(packet);
 263                         break;
 264         }
 265 }
 266
 267 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
 268 {
 269         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
 270
 271         switch (hp->state) {
 272                 case HVSI_WAIT_FOR_VER_RESPONSE:
 273                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
 274                         break;
 275                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
 276                         hp->mctrl = 0;
 277                         if (resp->u.mctrl_word & HVSI_TSDTR)
 278                                 hp->mctrl |= TIOCM_DTR;
 279                         if (resp->u.mctrl_word & HVSI_TSCD)
 280                                 hp->mctrl |= TIOCM_CD;
 281                         __set_state(hp, HVSI_OPEN);
 282                         break;
 283                 default:
 284                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
 285                         dump_packet(packet);
 286                         break;
 287         }
 288 }
 289
 290 /* respond to service processor's version query */
 291 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
 292 {
 293         struct hvsi_query_response packet __ALIGNED__;
 294         int wrote;
 295
 296         packet.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
 297         packet.hdr.len = sizeof(struct hvsi_query_response);
 298         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
 299         packet.verb = VSV_SEND_VERSION_NUMBER;
 300         packet.u.version = HVSI_VERSION;
 301         packet.query_seqno = query_seqno+1;
 302
 303         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 304         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 305
 306         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 307         if (wrote != packet.hdr.len) {
 308                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
 309                         hp->index);
 310                 return -EIO;
 311         }
 312
 313         return 0;
 314 }
 315
 316 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
 317 {
 318         struct hvsi_query *query = (struct hvsi_query *)packet;
 319
 320         switch (hp->state) {
 321                 case HVSI_WAIT_FOR_VER_QUERY:
 322                         hvsi_version_respond(hp, query->hdr.seqno);
 323                         __set_state(hp, HVSI_OPEN);
 324                         break;
 325                 default:
 326                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
 327                         dump_packet(packet);
 328                         break;
 329         }
 330 }
 331
 332 static void hvsi_insert_chars(struct hvsi_struct *hp, struct tty_struct *tty,
 333                 const char *buf, int len)
 334 {
 335         int i;
 336
 337         for (i=0; i < len; i++) {
 338                 char c = buf[i];
 339 #ifdef CONFIG_MAGIC_SYSRQ
 340                 if (c == '\0') {
 341                         hp->sysrq = 1;
 342                         continue;
 343                 } else if (hp->sysrq) {
 344                         handle_sysrq(c);
 345                         hp->sysrq = 0;
 346                         continue;
 347                 }
 348 #endif /* CONFIG_MAGIC_SYSRQ */
 349                 tty_insert_flip_char(tty, c, 0);
 350         }
 351 }
 352
 353 /*
 354  * We could get 252 bytes of data at once here. But the tty layer only
 355  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
 356  * it. Accordingly we won't send more than 128 bytes at a time to the flip
 357  * buffer, which will give the tty buffer a chance to throttle us. Should the
 358  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
 359  * revisited.
 360  */
 361 #define TTY_THRESHOLD_THROTTLE 128
 362 static bool hvsi_recv_data(struct hvsi_struct *hp, struct tty_struct *tty,
 363                 const uint8_t *packet)
 364 {
 365         const struct hvsi_header *header = (const struct hvsi_header *)packet;
 366         const uint8_t *data = packet + sizeof(struct hvsi_header);
 367         int datalen = header->len - sizeof(struct hvsi_header);
 368         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
 369
 370         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
 371
 372         if (datalen == 0)
 373                 return false;
 374
 375         if (overflow > 0) {
 376                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
 377                 datalen = TTY_THRESHOLD_THROTTLE;
 378         }
 379
 380         hvsi_insert_chars(hp, tty, data, datalen);
 381
 382         if (overflow > 0) {
 383                 /*
 384                  * we still have more data to deliver, so we need to save off the
 385                  * overflow and send it later
 386                  */
 387                 pr_debug("%s: deferring overflow\n", __func__);
 388                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
 389                 hp->n_throttle = overflow;
 390         }
 391
 392         return true;
 393 }
 394
 395 /*
 396  * Returns true/false indicating data successfully read from hypervisor.
 397  * Used both to get packets for tty connections and to advance the state
 398  * machine during console handshaking (in which case tty = NULL and we ignore
 399  * incoming data).
 400  */
 401 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct *tty,
 402                 struct hvsi_struct **handshake)
 403 {
 404         uint8_t *packet = hp->inbuf;
 405         int chunklen;
 406         bool flip = false;
 407
 408         *handshake = NULL;
 409
 410         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
 411         if (chunklen == 0) {
 412                 pr_debug("%s: 0-length read\n", __func__);
 413                 return 0;
 414         }
 415
 416         pr_debug("%s: got %i bytes\n", __func__, chunklen);
 417         dbg_dump_hex(hp->inbuf_end, chunklen);
 418
 419         hp->inbuf_end += chunklen;
 420
 421         /* handle all completed packets */
 422         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
 423                 struct hvsi_header *header = (struct hvsi_header *)packet;
 424
 425                 if (!is_header(packet)) {
 426                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
 427                         /* skip bytes until we find a header or run out of data */
 428                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
 429                                 packet++;
 430                         continue;
 431                 }
 432
 433                 pr_debug("%s: handling %i-byte packet\n", __func__,
 434                                 len_packet(packet));
 435                 dbg_dump_packet(packet);
 436
 437                 switch (header->type) {
 438                         case VS_DATA_PACKET_HEADER:
 439                                 if (!is_open(hp))
 440                                         break;
 441                                 if (tty == NULL)
 442                                         break; /* no tty buffer to put data in */
 443                                 flip = hvsi_recv_data(hp, tty, packet);
 444                                 break;
 445                         case VS_CONTROL_PACKET_HEADER:
 446                                 hvsi_recv_control(hp, packet, tty, handshake);
 447                                 break;
 448                         case VS_QUERY_RESPONSE_PACKET_HEADER:
 449                                 hvsi_recv_response(hp, packet);
 450                                 break;
 451                         case VS_QUERY_PACKET_HEADER:
 452                                 hvsi_recv_query(hp, packet);
 453                                 break;
 454                         default:
 455                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
 456                                                 hp->index, header->type);
 457                                 dump_packet(packet);
 458                                 break;
 459                 }
 460
 461                 packet += len_packet(packet);
 462
 463                 if (*handshake) {
 464                         pr_debug("%s: handshake\n", __func__);
 465                         break;
 466                 }
 467         }
 468
 469         compact_inbuf(hp, packet);
 470
 471         if (flip)
 472                 tty_flip_buffer_push(tty);
 473
 474         return 1;
 475 }
 476
 477 static void hvsi_send_overflow(struct hvsi_struct *hp, struct tty_struct *tty)
 478 {
 479         pr_debug("%s: delivering %i bytes overflow\n", __func__,
 480                         hp->n_throttle);
 481
 482         hvsi_insert_chars(hp, tty, hp->throttle_buf, hp->n_throttle);
 483         hp->n_throttle = 0;
 484 }
 485
 486 /*
 487  * must get all pending data because we only get an irq on empty->non-empty
 488  * transition
 489  */
 490 static irqreturn_t hvsi_interrupt(int irq, void *arg)
 491 {
 492         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 493         struct hvsi_struct *handshake;
 494         struct tty_struct *tty;
 495         unsigned long flags;
 496         int again = 1;
 497
 498         pr_debug("%s\n", __func__);
 499
 500         tty = tty_port_tty_get(&hp->port);
 501
 502         while (again) {
 503                 spin_lock_irqsave(&hp->lock, flags);
 504                 again = hvsi_load_chunk(hp, tty, &handshake);
 505                 spin_unlock_irqrestore(&hp->lock, flags);
 506
 507                 if (handshake) {
 508                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
 509                         schedule_work(&handshake->handshaker);
 510                 }
 511         }
 512
 513         spin_lock_irqsave(&hp->lock, flags);
 514         if (tty && hp->n_throttle && !test_bit(TTY_THROTTLED, &tty->flags)) {
 515                 /* we weren't hung up and we weren't throttled, so we can
 516                  * deliver the rest now */
 517                 hvsi_send_overflow(hp, tty);
 518                 tty_flip_buffer_push(tty);
 519         }
 520         spin_unlock_irqrestore(&hp->lock, flags);
 521
 522         tty_kref_put(tty);
 523
 524         return IRQ_HANDLED;
 525 }
 526
 527 /* for boot console, before the irq handler is running */
 528 static int __init poll_for_state(struct hvsi_struct *hp, int state)
 529 {
 530         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 531
 532         for (;;) {
 533                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
 534
 535                 if (hp->state == state)
 536                         return 0;
 537
 538                 mdelay(5);
 539                 if (time_after(jiffies, end_jiffies))
 540                         return -EIO;
 541         }
 542 }
 543
 544 /* wait for irq handler to change our state */
 545 static int wait_for_state(struct hvsi_struct *hp, int state)
 546 {
 547         int ret = 0;
 548
 549         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
 550                 ret = -EIO;
 551
 552         return ret;
 553 }
 554
 555 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
 556 {
 557         struct hvsi_query packet __ALIGNED__;
 558         int wrote;
 559
 560         packet.hdr.type = VS_QUERY_PACKET_HEADER;
 561         packet.hdr.len = sizeof(struct hvsi_query);
 562         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
 563         packet.verb = verb;
 564
 565         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 566         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 567
 568         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 569         if (wrote != packet.hdr.len) {
 570                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
 571                         wrote);
 572                 return -EIO;
 573         }
 574
 575         return 0;
 576 }
 577
 578 static int hvsi_get_mctrl(struct hvsi_struct *hp)
 579 {
 580         int ret;
 581
 582         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
 583         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
 584
 585         ret = hvsi_wait(hp, HVSI_OPEN);
 586         if (ret < 0) {
 587                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
 588                 set_state(hp, HVSI_OPEN);
 589                 return ret;
 590         }
 591
 592         pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
 593
 594         return 0;
 595 }
 596
 597 /* note that we can only set DTR */
 598 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
 599 {
 600         struct hvsi_control packet __ALIGNED__;
 601         int wrote;
 602
 603         packet.hdr.type = VS_CONTROL_PACKET_HEADER,
 604         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
 605         packet.hdr.len = sizeof(struct hvsi_control);
 606         packet.verb = VSV_SET_MODEM_CTL;
 607         packet.mask = HVSI_TSDTR;
 608
 609         if (mctrl & TIOCM_DTR)
 610                 packet.word = HVSI_TSDTR;
 611
 612         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 613         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 614
 615         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 616         if (wrote != packet.hdr.len) {
 617                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
 618                 return -EIO;
 619         }
 620
 621         return 0;
 622 }
 623
 624 static void hvsi_drain_input(struct hvsi_struct *hp)
 625 {
 626         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
 627         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 628
 629         while (time_before(end_jiffies, jiffies))
 630                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
 631                         break;
 632 }
 633
 634 static int hvsi_handshake(struct hvsi_struct *hp)
 635 {
 636         int ret;
 637
 638         /*
 639          * We could have a CLOSE or other data waiting for us before we even try
 640          * to open; try to throw it all away so we don't get confused. (CLOSE
 641          * is the first message sent up the pipe when the FSP comes online. We
 642          * need to distinguish between "it came up a while ago and we're the first
 643          * user" and "it was just reset before it saw our handshake packet".)
 644          */
 645         hvsi_drain_input(hp);
 646
 647         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
 648         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
 649         if (ret < 0) {
 650                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
 651                 return ret;
 652         }
 653
 654         ret = hvsi_wait(hp, HVSI_OPEN);
 655         if (ret < 0)
 656                 return ret;
 657
 658         return 0;
 659 }
 660
 661 static void hvsi_handshaker(struct work_struct *work)
 662 {
 663         struct hvsi_struct *hp =
 664                 container_of(work, struct hvsi_struct, handshaker);
 665
 666         if (hvsi_handshake(hp) >= 0)
 667                 return;
 668
 669         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
 670         if (is_console(hp)) {
 671                 /*
 672                  * ttys will re-attempt the handshake via hvsi_open, but
 673                  * the console will not.
 674                  */
 675                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
 676         }
 677 }
 678
 679 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
 680 {
 681         struct hvsi_data packet __ALIGNED__;
 682         int ret;
 683
 684         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
 685
 686         packet.hdr.type = VS_DATA_PACKET_HEADER;
 687         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
 688         packet.hdr.len = count + sizeof(struct hvsi_header);
 689         memcpy(&packet.data, buf, count);
 690
 691         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 692         if (ret == packet.hdr.len) {
 693                 /* return the number of chars written, not the packet length */
 694                 return count;
 695         }
 696         return ret; /* return any errors */
 697 }
 698
 699 static void hvsi_close_protocol(struct hvsi_struct *hp)
 700 {
 701         struct hvsi_control packet __ALIGNED__;
 702
 703         packet.hdr.type = VS_CONTROL_PACKET_HEADER;
 704         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
 705         packet.hdr.len = 6;
 706         packet.verb = VSV_CLOSE_PROTOCOL;
 707
 708         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 709         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 710
 711         hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 712 }
 713
 714 static int hvsi_open(struct tty_struct *tty, struct file *filp)
 715 {
 716         struct hvsi_struct *hp;
 717         unsigned long flags;
 718         int ret;
 719
 720         pr_debug("%s\n", __func__);
 721
 722         hp = &hvsi_ports[tty->index];
 723
 724         tty->driver_data = hp;
 725
 726         mb();
 727         if (hp->state == HVSI_FSP_DIED)
 728                 return -EIO;
 729
 730         tty_port_tty_set(&hp->port, tty);
 731         spin_lock_irqsave(&hp->lock, flags);
 732         hp->port.count++;
 733         atomic_set(&hp->seqno, 0);
 734         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
 735         spin_unlock_irqrestore(&hp->lock, flags);
 736
 737         if (is_console(hp))
 738                 return 0; /* this has already been handshaked as the console */
 739
 740         ret = hvsi_handshake(hp);
 741         if (ret < 0) {
 742                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
 743                 return ret;
 744         }
 745
 746         ret = hvsi_get_mctrl(hp);
 747         if (ret < 0) {
 748                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
 749                 return ret;
 750         }
 751
 752         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
 753         if (ret < 0) {
 754                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
 755                 return ret;
 756         }
 757
 758         return 0;
 759 }
 760
 761 /* wait for hvsi_write_worker to empty hp->outbuf */
 762 static void hvsi_flush_output(struct hvsi_struct *hp)
 763 {
 764         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
 765
 766         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
 767         cancel_delayed_work_sync(&hp->writer);
 768         flush_work(&hp->handshaker);
 769
 770         /*
 771          * it's also possible that our timeout expired and hvsi_write_worker
 772          * didn't manage to push outbuf. poof.
 773          */
 774         hp->n_outbuf = 0;
 775 }
 776
 777 static void hvsi_close(struct tty_struct *tty, struct file *filp)
 778 {
 779         struct hvsi_struct *hp = tty->driver_data;
 780         unsigned long flags;
 781
 782         pr_debug("%s\n", __func__);
 783
 784         if (tty_hung_up_p(filp))
 785                 return;
 786
 787         spin_lock_irqsave(&hp->lock, flags);
 788
 789         if (--hp->port.count == 0) {
 790                 tty_port_tty_set(&hp->port, NULL);
 791                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
 792
 793                 /* only close down connection if it is not the console */
 794                 if (!is_console(hp)) {
 795                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
 796                         __set_state(hp, HVSI_CLOSED);
 797                         /*
 798                          * any data delivered to the tty layer after this will be
 799                          * discarded (except for XON/XOFF)
 800                          */
 801                         tty->closing = 1;
 802
 803                         spin_unlock_irqrestore(&hp->lock, flags);
 804
 805                         /* let any existing irq handlers finish. no more will start. */
 806                         synchronize_irq(hp->virq);
 807
 808                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
 809                         hvsi_flush_output(hp);
 810
 811                         /* tell FSP to stop sending data */
 812                         hvsi_close_protocol(hp);
 813
 814                         /*
 815                          * drain anything FSP is still in the middle of sending, and let
 816                          * hvsi_handshake drain the rest on the next open.
 817                          */
 818                         hvsi_drain_input(hp);
 819
 820                         spin_lock_irqsave(&hp->lock, flags);
 821                 }
 822         } else if (hp->port.count < 0)
 823                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
 824                        hp - hvsi_ports, hp->port.count);
 825
 826         spin_unlock_irqrestore(&hp->lock, flags);
 827 }
 828
 829 static void hvsi_hangup(struct tty_struct *tty)
 830 {
 831         struct hvsi_struct *hp = tty->driver_data;
 832         unsigned long flags;
 833
 834         pr_debug("%s\n", __func__);
 835
 836         tty_port_tty_set(&hp->port, NULL);
 837
 838         spin_lock_irqsave(&hp->lock, flags);
 839         hp->port.count = 0;
 840         hp->n_outbuf = 0;
 841         spin_unlock_irqrestore(&hp->lock, flags);
 842 }
 843
 844 /* called with hp->lock held */
 845 static void hvsi_push(struct hvsi_struct *hp)
 846 {
 847         int n;
 848
 849         if (hp->n_outbuf <= 0)
 850                 return;
 851
 852         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
 853         if (n > 0) {
 854                 /* success */
 855                 pr_debug("%s: wrote %i chars\n", __func__, n);
 856                 hp->n_outbuf = 0;
 857         } else if (n == -EIO) {
 858                 __set_state(hp, HVSI_FSP_DIED);
 859                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
 860         }
 861 }
 862
 863 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
 864 static void hvsi_write_worker(struct work_struct *work)
 865 {
 866         struct hvsi_struct *hp =
 867                 container_of(work, struct hvsi_struct, writer.work);
 868         struct tty_struct *tty;
 869         unsigned long flags;
 870 #ifdef DEBUG
 871         static long start_j = 0;
 872
 873         if (start_j == 0)
 874                 start_j = jiffies;
 875 #endif /* DEBUG */
 876
 877         spin_lock_irqsave(&hp->lock, flags);
 878
 879         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
 880
 881         if (!is_open(hp)) {
 882                 /*
 883                  * We could have a non-open connection if the service processor died
 884                  * while we were busily scheduling ourselves. In that case, it could
 885                  * be minutes before the service processor comes back, so only try
 886                  * again once a second.
 887                  */
 888                 schedule_delayed_work(&hp->writer, HZ);
 889                 goto out;
 890         }
 891
 892         hvsi_push(hp);
 893         if (hp->n_outbuf > 0)
 894                 schedule_delayed_work(&hp->writer, 10);
 895         else {
 896 #ifdef DEBUG
 897                 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
 898                                 jiffies - start_j);
 899                 start_j = 0;
 900 #endif /* DEBUG */
 901                 wake_up_all(&hp->emptyq);
 902                 tty = tty_port_tty_get(&hp->port);
 903                 if (tty) {
 904                         tty_wakeup(tty);
 905                         tty_kref_put(tty);
 906                 }
 907         }
 908
 909 out:
 910         spin_unlock_irqrestore(&hp->lock, flags);
 911 }
 912
 913 static int hvsi_write_room(struct tty_struct *tty)
 914 {
 915         struct hvsi_struct *hp = tty->driver_data;
 916
 917         return N_OUTBUF - hp->n_outbuf;
 918 }
 919
 920 static int hvsi_chars_in_buffer(struct tty_struct *tty)
 921 {
 922         struct hvsi_struct *hp = tty->driver_data;
 923
 924         return hp->n_outbuf;
 925 }
 926
 927 static int hvsi_write(struct tty_struct *tty,
 928                      const unsigned char *buf, int count)
 929 {
 930         struct hvsi_struct *hp = tty->driver_data;
 931         const char *source = buf;
 932         unsigned long flags;
 933         int total = 0;
 934         int origcount = count;
 935
 936         spin_lock_irqsave(&hp->lock, flags);
 937
 938         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
 939
 940         if (!is_open(hp)) {
 941                 /* we're either closing or not yet open; don't accept data */
 942                 pr_debug("%s: not open\n", __func__);
 943                 goto out;
 944         }
 945
 946         /*
 947          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
 948          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
 949          * will see there is no room in outbuf and return.
 950          */
 951         while ((count > 0) && (hvsi_write_room(tty) > 0)) {
 952                 int chunksize = min(count, hvsi_write_room(tty));
 953
 954                 BUG_ON(hp->n_outbuf < 0);
 955                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
 956                 hp->n_outbuf += chunksize;
 957
 958                 total += chunksize;
 959                 source += chunksize;
 960                 count -= chunksize;
 961                 hvsi_push(hp);
 962         }
 963
 964         if (hp->n_outbuf > 0) {
 965                 /*
 966                  * we weren't able to write it all to the hypervisor.
 967                  * schedule another push attempt.
 968                  */
 969                 schedule_delayed_work(&hp->writer, 10);
 970         }
 971
 972 out:
 973         spin_unlock_irqrestore(&hp->lock, flags);
 974
 975         if (total != origcount)
 976                 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
 977                         total);
 978
 979         return total;
 980 }
 981
 982 /*
 983  * I have never seen throttle or unthrottle called, so this little throttle
 984  * buffering scheme may or may not work.
 985  */
 986 static void hvsi_throttle(struct tty_struct *tty)
 987 {
 988         struct hvsi_struct *hp = tty->driver_data;
 989
 990         pr_debug("%s\n", __func__);
 991
 992         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
 993 }
 994
 995 static void hvsi_unthrottle(struct tty_struct *tty)
 996 {
 997         struct hvsi_struct *hp = tty->driver_data;
 998         unsigned long flags;
 999
1000         pr_debug("%s\n", __func__);
1001
1002         spin_lock_irqsave(&hp->lock, flags);
1003         if (hp->n_throttle) {
1004                 hvsi_send_overflow(hp, tty);
1005                 tty_flip_buffer_push(tty);
1006         }
1007         spin_unlock_irqrestore(&hp->lock, flags);
1008
1009
1010         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1011 }
1012
1013 static int hvsi_tiocmget(struct tty_struct *tty)
1014 {
1015         struct hvsi_struct *hp = tty->driver_data;
1016
1017         hvsi_get_mctrl(hp);
1018         return hp->mctrl;
1019 }
1020
1021 static int hvsi_tiocmset(struct tty_struct *tty,
1022                                 unsigned int set, unsigned int clear)
1023 {
1024         struct hvsi_struct *hp = tty->driver_data;
1025         unsigned long flags;
1026         uint16_t new_mctrl;
1027
1028         /* we can only alter DTR */
1029         clear &= TIOCM_DTR;
1030         set &= TIOCM_DTR;
1031
1032         spin_lock_irqsave(&hp->lock, flags);
1033
1034         new_mctrl = (hp->mctrl & ~clear) | set;
1035
1036         if (hp->mctrl != new_mctrl) {
1037                 hvsi_set_mctrl(hp, new_mctrl);
1038                 hp->mctrl = new_mctrl;
1039         }
1040         spin_unlock_irqrestore(&hp->lock, flags);
1041
1042         return 0;
1043 }
1044
1045
1046 static const struct tty_operations hvsi_ops = {
1047         .open = hvsi_open,
1048         .close = hvsi_close,
1049         .write = hvsi_write,
1050         .hangup = hvsi_hangup,
1051         .write_room = hvsi_write_room,
1052         .chars_in_buffer = hvsi_chars_in_buffer,
1053         .throttle = hvsi_throttle,
1054         .unthrottle = hvsi_unthrottle,
1055         .tiocmget = hvsi_tiocmget,
1056         .tiocmset = hvsi_tiocmset,
1057 };
1058
1059 static int __init hvsi_init(void)
1060 {
1061         int i;
1062
1063         hvsi_driver = alloc_tty_driver(hvsi_count);
1064         if (!hvsi_driver)
1065                 return -ENOMEM;
1066
1067         hvsi_driver->driver_name = "hvsi";
1068         hvsi_driver->name = "hvsi";
1069         hvsi_driver->major = HVSI_MAJOR;
1070         hvsi_driver->minor_start = HVSI_MINOR;
1071         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1072         hvsi_driver->init_termios = tty_std_termios;
1073         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1074         hvsi_driver->init_termios.c_ispeed = 9600;
1075         hvsi_driver->init_termios.c_ospeed = 9600;
1076         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1077         tty_set_operations(hvsi_driver, &hvsi_ops);
1078
1079         for (i=0; i < hvsi_count; i++) {
1080                 struct hvsi_struct *hp = &hvsi_ports[i];
1081                 int ret = 1;
1082
1083                 tty_port_link_device(&hp->port, hvsi_driver, i);
1084
1085                 ret = request_irq(hp->virq, hvsi_interrupt, 0, "hvsi", hp);
1086                 if (ret)
1087                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1088                                 hp->virq, ret);
1089         }
1090         hvsi_wait = wait_for_state; /* irqs active now */
1091
1092         if (tty_register_driver(hvsi_driver))
1093                 panic("Couldn't register hvsi console driver\n");
1094
1095         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1096
1097         return 0;
1098 }
1099 device_initcall(hvsi_init);
1100
1101 /***** console (not tty) code: *****/
1102
1103 static void hvsi_console_print(struct console *console, const char *buf,
1104                 unsigned int count)
1105 {
1106         struct hvsi_struct *hp = &hvsi_ports[console->index];
1107         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1108         unsigned int i = 0, n = 0;
1109         int ret, donecr = 0;
1110
1111         mb();
1112         if (!is_open(hp))
1113                 return;
1114
1115         /*
1116          * ugh, we have to translate LF -> CRLF ourselves, in place.
1117          * copied from hvc_console.c:
1118          */
1119         while (count > 0 || i > 0) {
1120                 if (count > 0 && i < sizeof(c)) {
1121                         if (buf[n] == '\n' && !donecr) {
1122                                 c[i++] = '\r';
1123                                 donecr = 1;
1124                         } else {
1125                                 c[i++] = buf[n++];
1126                                 donecr = 0;
1127                                 --count;
1128                         }
1129                 } else {
1130                         ret = hvsi_put_chars(hp, c, i);
1131                         if (ret < 0)
1132                                 i = 0;
1133                         i -= ret;
1134                 }
1135         }
1136 }
1137
1138 static struct tty_driver *hvsi_console_device(struct console *console,
1139         int *index)
1140 {
1141         *index = console->index;
1142         return hvsi_driver;
1143 }
1144
1145 static int __init hvsi_console_setup(struct console *console, char *options)
1146 {
1147         struct hvsi_struct *hp;
1148         int ret;
1149
1150         if (console->index < 0 || console->index >= hvsi_count)
1151                 return -1;
1152         hp = &hvsi_ports[console->index];
1153
1154         /* give the FSP a chance to change the baud rate when we re-open */
1155         hvsi_close_protocol(hp);
1156
1157         ret = hvsi_handshake(hp);
1158         if (ret < 0)
1159                 return ret;
1160
1161         ret = hvsi_get_mctrl(hp);
1162         if (ret < 0)
1163                 return ret;
1164
1165         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1166         if (ret < 0)
1167                 return ret;
1168
1169         hp->flags |= HVSI_CONSOLE;
1170
1171         return 0;
1172 }
1173
1174 static struct console hvsi_console = {
1175         .name           = "hvsi",
1176         .write          = hvsi_console_print,
1177         .device         = hvsi_console_device,
1178         .setup          = hvsi_console_setup,
1179         .flags          = CON_PRINTBUFFER,
1180         .index          = -1,
1181 };
1182
1183 static int __init hvsi_console_init(void)
1184 {
1185         struct device_node *vty;
1186
1187         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1188
1189         /* search device tree for vty nodes */
1190         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1191                         vty != NULL;
1192                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1193                 struct hvsi_struct *hp;
1194                 const uint32_t *vtermno, *irq;
1195
1196                 vtermno = of_get_property(vty, "reg", NULL);
1197                 irq = of_get_property(vty, "interrupts", NULL);
1198                 if (!vtermno || !irq)
1199                         continue;
1200
1201                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1202                         of_node_put(vty);
1203                         break;
1204                 }
1205
1206                 hp = &hvsi_ports[hvsi_count];
1207                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1208                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1209                 init_waitqueue_head(&hp->emptyq);
1210                 init_waitqueue_head(&hp->stateq);
1211                 spin_lock_init(&hp->lock);
1212                 tty_port_init(&hp->port);
1213                 hp->index = hvsi_count;
1214                 hp->inbuf_end = hp->inbuf;
1215                 hp->state = HVSI_CLOSED;
1216                 hp->vtermno = *vtermno;
1217                 hp->virq = irq_create_mapping(NULL, irq[0]);
1218                 if (hp->virq == 0) {
1219                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1220                                 __func__, irq[0]);
1221                         tty_port_destroy(&hp->port);
1222                         continue;
1223                 }
1224
1225                 hvsi_count++;
1226         }
1227
1228         if (hvsi_count)
1229                 register_console(&hvsi_console);
1230         return 0;
1231 }
1232 console_initcall(hvsi_console_init);