kernel/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 (be16_to_cpu(header->verb)) {
 244                 case VSV_MODEM_CTL_UPDATE:
 245                         if ((be32_to_cpu(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         uint32_t mctrl_word;
 271
 272         switch (hp->state) {
 273                 case HVSI_WAIT_FOR_VER_RESPONSE:
 274                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
 275                         break;
 276                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
 277                         hp->mctrl = 0;
 278                         mctrl_word = be32_to_cpu(resp->u.mctrl_word);
 279                         if (mctrl_word & HVSI_TSDTR)
 280                                 hp->mctrl |= TIOCM_DTR;
 281                         if (mctrl_word & HVSI_TSCD)
 282                                 hp->mctrl |= TIOCM_CD;
 283                         __set_state(hp, HVSI_OPEN);
 284                         break;
 285                 default:
 286                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
 287                         dump_packet(packet);
 288                         break;
 289         }
 290 }
 291
 292 /* respond to service processor's version query */
 293 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
 294 {
 295         struct hvsi_query_response packet __ALIGNED__;
 296         int wrote;
 297
 298         packet.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
 299         packet.hdr.len = sizeof(struct hvsi_query_response);
 300         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
 301         packet.verb = cpu_to_be16(VSV_SEND_VERSION_NUMBER);
 302         packet.u.version = HVSI_VERSION;
 303         packet.query_seqno = cpu_to_be16(query_seqno+1);
 304
 305         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 306         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 307
 308         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 309         if (wrote != packet.hdr.len) {
 310                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
 311                         hp->index);
 312                 return -EIO;
 313         }
 314
 315         return 0;
 316 }
 317
 318 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
 319 {
 320         struct hvsi_query *query = (struct hvsi_query *)packet;
 321
 322         switch (hp->state) {
 323                 case HVSI_WAIT_FOR_VER_QUERY:
 324                         hvsi_version_respond(hp, be16_to_cpu(query->hdr.seqno));
 325                         __set_state(hp, HVSI_OPEN);
 326                         break;
 327                 default:
 328                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
 329                         dump_packet(packet);
 330                         break;
 331         }
 332 }
 333
 334 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
 335 {
 336         int i;
 337
 338         for (i=0; i < len; i++) {
 339                 char c = buf[i];
 340 #ifdef CONFIG_MAGIC_SYSRQ
 341                 if (c == '\0') {
 342                         hp->sysrq = 1;
 343                         continue;
 344                 } else if (hp->sysrq) {
 345                         handle_sysrq(c);
 346                         hp->sysrq = 0;
 347                         continue;
 348                 }
 349 #endif /* CONFIG_MAGIC_SYSRQ */
 350                 tty_insert_flip_char(&hp->port, c, 0);
 351         }
 352 }
 353
 354 /*
 355  * We could get 252 bytes of data at once here. But the tty layer only
 356  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
 357  * it. Accordingly we won't send more than 128 bytes at a time to the flip
 358  * buffer, which will give the tty buffer a chance to throttle us. Should the
 359  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
 360  * revisited.
 361  */
 362 #define TTY_THRESHOLD_THROTTLE 128
 363 static bool hvsi_recv_data(struct hvsi_struct *hp, 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, 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                                 flip = hvsi_recv_data(hp, packet);
 442                                 break;
 443                         case VS_CONTROL_PACKET_HEADER:
 444                                 hvsi_recv_control(hp, packet, tty, handshake);
 445                                 break;
 446                         case VS_QUERY_RESPONSE_PACKET_HEADER:
 447                                 hvsi_recv_response(hp, packet);
 448                                 break;
 449                         case VS_QUERY_PACKET_HEADER:
 450                                 hvsi_recv_query(hp, packet);
 451                                 break;
 452                         default:
 453                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
 454                                                 hp->index, header->type);
 455                                 dump_packet(packet);
 456                                 break;
 457                 }
 458
 459                 packet += len_packet(packet);
 460
 461                 if (*handshake) {
 462                         pr_debug("%s: handshake\n", __func__);
 463                         break;
 464                 }
 465         }
 466
 467         compact_inbuf(hp, packet);
 468
 469         if (flip)
 470                 tty_flip_buffer_push(&hp->port);
 471
 472         return 1;
 473 }
 474
 475 static void hvsi_send_overflow(struct hvsi_struct *hp)
 476 {
 477         pr_debug("%s: delivering %i bytes overflow\n", __func__,
 478                         hp->n_throttle);
 479
 480         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
 481         hp->n_throttle = 0;
 482 }
 483
 484 /*
 485  * must get all pending data because we only get an irq on empty->non-empty
 486  * transition
 487  */
 488 static irqreturn_t hvsi_interrupt(int irq, void *arg)
 489 {
 490         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 491         struct hvsi_struct *handshake;
 492         struct tty_struct *tty;
 493         unsigned long flags;
 494         int again = 1;
 495
 496         pr_debug("%s\n", __func__);
 497
 498         tty = tty_port_tty_get(&hp->port);
 499
 500         while (again) {
 501                 spin_lock_irqsave(&hp->lock, flags);
 502                 again = hvsi_load_chunk(hp, tty, &handshake);
 503                 spin_unlock_irqrestore(&hp->lock, flags);
 504
 505                 if (handshake) {
 506                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
 507                         schedule_work(&handshake->handshaker);
 508                 }
 509         }
 510
 511         spin_lock_irqsave(&hp->lock, flags);
 512         if (tty && hp->n_throttle && !test_bit(TTY_THROTTLED, &tty->flags)) {
 513                 /* we weren't hung up and we weren't throttled, so we can
 514                  * deliver the rest now */
 515                 hvsi_send_overflow(hp);
 516                 tty_flip_buffer_push(&hp->port);
 517         }
 518         spin_unlock_irqrestore(&hp->lock, flags);
 519
 520         tty_kref_put(tty);
 521
 522         return IRQ_HANDLED;
 523 }
 524
 525 /* for boot console, before the irq handler is running */
 526 static int __init poll_for_state(struct hvsi_struct *hp, int state)
 527 {
 528         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 529
 530         for (;;) {
 531                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
 532
 533                 if (hp->state == state)
 534                         return 0;
 535
 536                 mdelay(5);
 537                 if (time_after(jiffies, end_jiffies))
 538                         return -EIO;
 539         }
 540 }
 541
 542 /* wait for irq handler to change our state */
 543 static int wait_for_state(struct hvsi_struct *hp, int state)
 544 {
 545         int ret = 0;
 546
 547         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
 548                 ret = -EIO;
 549
 550         return ret;
 551 }
 552
 553 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
 554 {
 555         struct hvsi_query packet __ALIGNED__;
 556         int wrote;
 557
 558         packet.hdr.type = VS_QUERY_PACKET_HEADER;
 559         packet.hdr.len = sizeof(struct hvsi_query);
 560         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
 561         packet.verb = cpu_to_be16(verb);
 562
 563         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 564         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 565
 566         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 567         if (wrote != packet.hdr.len) {
 568                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
 569                         wrote);
 570                 return -EIO;
 571         }
 572
 573         return 0;
 574 }
 575
 576 static int hvsi_get_mctrl(struct hvsi_struct *hp)
 577 {
 578         int ret;
 579
 580         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
 581         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
 582
 583         ret = hvsi_wait(hp, HVSI_OPEN);
 584         if (ret < 0) {
 585                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
 586                 set_state(hp, HVSI_OPEN);
 587                 return ret;
 588         }
 589
 590         pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
 591
 592         return 0;
 593 }
 594
 595 /* note that we can only set DTR */
 596 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
 597 {
 598         struct hvsi_control packet __ALIGNED__;
 599         int wrote;
 600
 601         packet.hdr.type = VS_CONTROL_PACKET_HEADER;
 602         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
 603         packet.hdr.len = sizeof(struct hvsi_control);
 604         packet.verb = cpu_to_be16(VSV_SET_MODEM_CTL);
 605         packet.mask = cpu_to_be32(HVSI_TSDTR);
 606
 607         if (mctrl & TIOCM_DTR)
 608                 packet.word = cpu_to_be32(HVSI_TSDTR);
 609
 610         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 611         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 612
 613         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 614         if (wrote != packet.hdr.len) {
 615                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
 616                 return -EIO;
 617         }
 618
 619         return 0;
 620 }
 621
 622 static void hvsi_drain_input(struct hvsi_struct *hp)
 623 {
 624         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
 625         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 626
 627         while (time_before(end_jiffies, jiffies))
 628                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
 629                         break;
 630 }
 631
 632 static int hvsi_handshake(struct hvsi_struct *hp)
 633 {
 634         int ret;
 635
 636         /*
 637          * We could have a CLOSE or other data waiting for us before we even try
 638          * to open; try to throw it all away so we don't get confused. (CLOSE
 639          * is the first message sent up the pipe when the FSP comes online. We
 640          * need to distinguish between "it came up a while ago and we're the first
 641          * user" and "it was just reset before it saw our handshake packet".)
 642          */
 643         hvsi_drain_input(hp);
 644
 645         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
 646         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
 647         if (ret < 0) {
 648                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
 649                 return ret;
 650         }
 651
 652         ret = hvsi_wait(hp, HVSI_OPEN);
 653         if (ret < 0)
 654                 return ret;
 655
 656         return 0;
 657 }
 658
 659 static void hvsi_handshaker(struct work_struct *work)
 660 {
 661         struct hvsi_struct *hp =
 662                 container_of(work, struct hvsi_struct, handshaker);
 663
 664         if (hvsi_handshake(hp) >= 0)
 665                 return;
 666
 667         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
 668         if (is_console(hp)) {
 669                 /*
 670                  * ttys will re-attempt the handshake via hvsi_open, but
 671                  * the console will not.
 672                  */
 673                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
 674         }
 675 }
 676
 677 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
 678 {
 679         struct hvsi_data packet __ALIGNED__;
 680         int ret;
 681
 682         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
 683
 684         packet.hdr.type = VS_DATA_PACKET_HEADER;
 685         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
 686         packet.hdr.len = count + sizeof(struct hvsi_header);
 687         memcpy(&packet.data, buf, count);
 688
 689         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 690         if (ret == packet.hdr.len) {
 691                 /* return the number of chars written, not the packet length */
 692                 return count;
 693         }
 694         return ret; /* return any errors */
 695 }
 696
 697 static void hvsi_close_protocol(struct hvsi_struct *hp)
 698 {
 699         struct hvsi_control packet __ALIGNED__;
 700
 701         packet.hdr.type = VS_CONTROL_PACKET_HEADER;
 702         packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno));
 703         packet.hdr.len = 6;
 704         packet.verb = cpu_to_be16(VSV_CLOSE_PROTOCOL);
 705
 706         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 707         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 708
 709         hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 710 }
 711
 712 static int hvsi_open(struct tty_struct *tty, struct file *filp)
 713 {
 714         struct hvsi_struct *hp;
 715         unsigned long flags;
 716         int ret;
 717
 718         pr_debug("%s\n", __func__);
 719
 720         hp = &hvsi_ports[tty->index];
 721
 722         tty->driver_data = hp;
 723
 724         mb();
 725         if (hp->state == HVSI_FSP_DIED)
 726                 return -EIO;
 727
 728         tty_port_tty_set(&hp->port, tty);
 729         spin_lock_irqsave(&hp->lock, flags);
 730         hp->port.count++;
 731         atomic_set(&hp->seqno, 0);
 732         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
 733         spin_unlock_irqrestore(&hp->lock, flags);
 734
 735         if (is_console(hp))
 736                 return 0; /* this has already been handshaked as the console */
 737
 738         ret = hvsi_handshake(hp);
 739         if (ret < 0) {
 740                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
 741                 return ret;
 742         }
 743
 744         ret = hvsi_get_mctrl(hp);
 745         if (ret < 0) {
 746                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
 747                 return ret;
 748         }
 749
 750         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
 751         if (ret < 0) {
 752                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
 753                 return ret;
 754         }
 755
 756         return 0;
 757 }
 758
 759 /* wait for hvsi_write_worker to empty hp->outbuf */
 760 static void hvsi_flush_output(struct hvsi_struct *hp)
 761 {
 762         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
 763
 764         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
 765         cancel_delayed_work_sync(&hp->writer);
 766         flush_work(&hp->handshaker);
 767
 768         /*
 769          * it's also possible that our timeout expired and hvsi_write_worker
 770          * didn't manage to push outbuf. poof.
 771          */
 772         hp->n_outbuf = 0;
 773 }
 774
 775 static void hvsi_close(struct tty_struct *tty, struct file *filp)
 776 {
 777         struct hvsi_struct *hp = tty->driver_data;
 778         unsigned long flags;
 779
 780         pr_debug("%s\n", __func__);
 781
 782         if (tty_hung_up_p(filp))
 783                 return;
 784
 785         spin_lock_irqsave(&hp->lock, flags);
 786
 787         if (--hp->port.count == 0) {
 788                 tty_port_tty_set(&hp->port, NULL);
 789                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
 790
 791                 /* only close down connection if it is not the console */
 792                 if (!is_console(hp)) {
 793                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
 794                         __set_state(hp, HVSI_CLOSED);
 795                         /*
 796                          * any data delivered to the tty layer after this will be
 797                          * discarded (except for XON/XOFF)
 798                          */
 799                         tty->closing = 1;
 800
 801                         spin_unlock_irqrestore(&hp->lock, flags);
 802
 803                         /* let any existing irq handlers finish. no more will start. */
 804                         synchronize_irq(hp->virq);
 805
 806                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
 807                         hvsi_flush_output(hp);
 808
 809                         /* tell FSP to stop sending data */
 810                         hvsi_close_protocol(hp);
 811
 812                         /*
 813                          * drain anything FSP is still in the middle of sending, and let
 814                          * hvsi_handshake drain the rest on the next open.
 815                          */
 816                         hvsi_drain_input(hp);
 817
 818                         spin_lock_irqsave(&hp->lock, flags);
 819                 }
 820         } else if (hp->port.count < 0)
 821                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
 822                        hp - hvsi_ports, hp->port.count);
 823
 824         spin_unlock_irqrestore(&hp->lock, flags);
 825 }
 826
 827 static void hvsi_hangup(struct tty_struct *tty)
 828 {
 829         struct hvsi_struct *hp = tty->driver_data;
 830         unsigned long flags;
 831
 832         pr_debug("%s\n", __func__);
 833
 834         tty_port_tty_set(&hp->port, NULL);
 835
 836         spin_lock_irqsave(&hp->lock, flags);
 837         hp->port.count = 0;
 838         hp->n_outbuf = 0;
 839         spin_unlock_irqrestore(&hp->lock, flags);
 840 }
 841
 842 /* called with hp->lock held */
 843 static void hvsi_push(struct hvsi_struct *hp)
 844 {
 845         int n;
 846
 847         if (hp->n_outbuf <= 0)
 848                 return;
 849
 850         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
 851         if (n > 0) {
 852                 /* success */
 853                 pr_debug("%s: wrote %i chars\n", __func__, n);
 854                 hp->n_outbuf = 0;
 855         } else if (n == -EIO) {
 856                 __set_state(hp, HVSI_FSP_DIED);
 857                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
 858         }
 859 }
 860
 861 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
 862 static void hvsi_write_worker(struct work_struct *work)
 863 {
 864         struct hvsi_struct *hp =
 865                 container_of(work, struct hvsi_struct, writer.work);
 866         unsigned long flags;
 867 #ifdef DEBUG
 868         static long start_j = 0;
 869
 870         if (start_j == 0)
 871                 start_j = jiffies;
 872 #endif /* DEBUG */
 873
 874         spin_lock_irqsave(&hp->lock, flags);
 875
 876         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
 877
 878         if (!is_open(hp)) {
 879                 /*
 880                  * We could have a non-open connection if the service processor died
 881                  * while we were busily scheduling ourselves. In that case, it could
 882                  * be minutes before the service processor comes back, so only try
 883                  * again once a second.
 884                  */
 885                 schedule_delayed_work(&hp->writer, HZ);
 886                 goto out;
 887         }
 888
 889         hvsi_push(hp);
 890         if (hp->n_outbuf > 0)
 891                 schedule_delayed_work(&hp->writer, 10);
 892         else {
 893 #ifdef DEBUG
 894                 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
 895                                 jiffies - start_j);
 896                 start_j = 0;
 897 #endif /* DEBUG */
 898                 wake_up_all(&hp->emptyq);
 899                 tty_port_tty_wakeup(&hp->port);
 900         }
 901
 902 out:
 903         spin_unlock_irqrestore(&hp->lock, flags);
 904 }
 905
 906 static int hvsi_write_room(struct tty_struct *tty)
 907 {
 908         struct hvsi_struct *hp = tty->driver_data;
 909
 910         return N_OUTBUF - hp->n_outbuf;
 911 }
 912
 913 static int hvsi_chars_in_buffer(struct tty_struct *tty)
 914 {
 915         struct hvsi_struct *hp = tty->driver_data;
 916
 917         return hp->n_outbuf;
 918 }
 919
 920 static int hvsi_write(struct tty_struct *tty,
 921                      const unsigned char *buf, int count)
 922 {
 923         struct hvsi_struct *hp = tty->driver_data;
 924         const char *source = buf;
 925         unsigned long flags;
 926         int total = 0;
 927         int origcount = count;
 928
 929         spin_lock_irqsave(&hp->lock, flags);
 930
 931         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
 932
 933         if (!is_open(hp)) {
 934                 /* we're either closing or not yet open; don't accept data */
 935                 pr_debug("%s: not open\n", __func__);
 936                 goto out;
 937         }
 938
 939         /*
 940          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
 941          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
 942          * will see there is no room in outbuf and return.
 943          */
 944         while ((count > 0) && (hvsi_write_room(tty) > 0)) {
 945                 int chunksize = min(count, hvsi_write_room(tty));
 946
 947                 BUG_ON(hp->n_outbuf < 0);
 948                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
 949                 hp->n_outbuf += chunksize;
 950
 951                 total += chunksize;
 952                 source += chunksize;
 953                 count -= chunksize;
 954                 hvsi_push(hp);
 955         }
 956
 957         if (hp->n_outbuf > 0) {
 958                 /*
 959                  * we weren't able to write it all to the hypervisor.
 960                  * schedule another push attempt.
 961                  */
 962                 schedule_delayed_work(&hp->writer, 10);
 963         }
 964
 965 out:
 966         spin_unlock_irqrestore(&hp->lock, flags);
 967
 968         if (total != origcount)
 969                 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
 970                         total);
 971
 972         return total;
 973 }
 974
 975 /*
 976  * I have never seen throttle or unthrottle called, so this little throttle
 977  * buffering scheme may or may not work.
 978  */
 979 static void hvsi_throttle(struct tty_struct *tty)
 980 {
 981         struct hvsi_struct *hp = tty->driver_data;
 982
 983         pr_debug("%s\n", __func__);
 984
 985         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
 986 }
 987
 988 static void hvsi_unthrottle(struct tty_struct *tty)
 989 {
 990         struct hvsi_struct *hp = tty->driver_data;
 991         unsigned long flags;
 992
 993         pr_debug("%s\n", __func__);
 994
 995         spin_lock_irqsave(&hp->lock, flags);
 996         if (hp->n_throttle) {
 997                 hvsi_send_overflow(hp);
 998                 tty_flip_buffer_push(&hp->port);
 999         }
1000         spin_unlock_irqrestore(&hp->lock, flags);
1001
1002
1003         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1004 }
1005
1006 static int hvsi_tiocmget(struct tty_struct *tty)
1007 {
1008         struct hvsi_struct *hp = tty->driver_data;
1009
1010         hvsi_get_mctrl(hp);
1011         return hp->mctrl;
1012 }
1013
1014 static int hvsi_tiocmset(struct tty_struct *tty,
1015                                 unsigned int set, unsigned int clear)
1016 {
1017         struct hvsi_struct *hp = tty->driver_data;
1018         unsigned long flags;
1019         uint16_t new_mctrl;
1020
1021         /* we can only alter DTR */
1022         clear &= TIOCM_DTR;
1023         set &= TIOCM_DTR;
1024
1025         spin_lock_irqsave(&hp->lock, flags);
1026
1027         new_mctrl = (hp->mctrl & ~clear) | set;
1028
1029         if (hp->mctrl != new_mctrl) {
1030                 hvsi_set_mctrl(hp, new_mctrl);
1031                 hp->mctrl = new_mctrl;
1032         }
1033         spin_unlock_irqrestore(&hp->lock, flags);
1034
1035         return 0;
1036 }
1037
1038
1039 static const struct tty_operations hvsi_ops = {
1040         .open = hvsi_open,
1041         .close = hvsi_close,
1042         .write = hvsi_write,
1043         .hangup = hvsi_hangup,
1044         .write_room = hvsi_write_room,
1045         .chars_in_buffer = hvsi_chars_in_buffer,
1046         .throttle = hvsi_throttle,
1047         .unthrottle = hvsi_unthrottle,
1048         .tiocmget = hvsi_tiocmget,
1049         .tiocmset = hvsi_tiocmset,
1050 };
1051
1052 static int __init hvsi_init(void)
1053 {
1054         int i;
1055
1056         hvsi_driver = alloc_tty_driver(hvsi_count);
1057         if (!hvsi_driver)
1058                 return -ENOMEM;
1059
1060         hvsi_driver->driver_name = "hvsi";
1061         hvsi_driver->name = "hvsi";
1062         hvsi_driver->major = HVSI_MAJOR;
1063         hvsi_driver->minor_start = HVSI_MINOR;
1064         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1065         hvsi_driver->init_termios = tty_std_termios;
1066         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1067         hvsi_driver->init_termios.c_ispeed = 9600;
1068         hvsi_driver->init_termios.c_ospeed = 9600;
1069         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1070         tty_set_operations(hvsi_driver, &hvsi_ops);
1071
1072         for (i=0; i < hvsi_count; i++) {
1073                 struct hvsi_struct *hp = &hvsi_ports[i];
1074                 int ret = 1;
1075
1076                 tty_port_link_device(&hp->port, hvsi_driver, i);
1077
1078                 ret = request_irq(hp->virq, hvsi_interrupt, 0, "hvsi", hp);
1079                 if (ret)
1080                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1081                                 hp->virq, ret);
1082         }
1083         hvsi_wait = wait_for_state; /* irqs active now */
1084
1085         if (tty_register_driver(hvsi_driver))
1086                 panic("Couldn't register hvsi console driver\n");
1087
1088         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1089
1090         return 0;
1091 }
1092 device_initcall(hvsi_init);
1093
1094 /***** console (not tty) code: *****/
1095
1096 static void hvsi_console_print(struct console *console, const char *buf,
1097                 unsigned int count)
1098 {
1099         struct hvsi_struct *hp = &hvsi_ports[console->index];
1100         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1101         unsigned int i = 0, n = 0;
1102         int ret, donecr = 0;
1103
1104         mb();
1105         if (!is_open(hp))
1106                 return;
1107
1108         /*
1109          * ugh, we have to translate LF -> CRLF ourselves, in place.
1110          * copied from hvc_console.c:
1111          */
1112         while (count > 0 || i > 0) {
1113                 if (count > 0 && i < sizeof(c)) {
1114                         if (buf[n] == '\n' && !donecr) {
1115                                 c[i++] = '\r';
1116                                 donecr = 1;
1117                         } else {
1118                                 c[i++] = buf[n++];
1119                                 donecr = 0;
1120                                 --count;
1121                         }
1122                 } else {
1123                         ret = hvsi_put_chars(hp, c, i);
1124                         if (ret < 0)
1125                                 i = 0;
1126                         i -= ret;
1127                 }
1128         }
1129 }
1130
1131 static struct tty_driver *hvsi_console_device(struct console *console,
1132         int *index)
1133 {
1134         *index = console->index;
1135         return hvsi_driver;
1136 }
1137
1138 static int __init hvsi_console_setup(struct console *console, char *options)
1139 {
1140         struct hvsi_struct *hp;
1141         int ret;
1142
1143         if (console->index < 0 || console->index >= hvsi_count)
1144                 return -1;
1145         hp = &hvsi_ports[console->index];
1146
1147         /* give the FSP a chance to change the baud rate when we re-open */
1148         hvsi_close_protocol(hp);
1149
1150         ret = hvsi_handshake(hp);
1151         if (ret < 0)
1152                 return ret;
1153
1154         ret = hvsi_get_mctrl(hp);
1155         if (ret < 0)
1156                 return ret;
1157
1158         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1159         if (ret < 0)
1160                 return ret;
1161
1162         hp->flags |= HVSI_CONSOLE;
1163
1164         return 0;
1165 }
1166
1167 static struct console hvsi_console = {
1168         .name           = "hvsi",
1169         .write          = hvsi_console_print,
1170         .device         = hvsi_console_device,
1171         .setup          = hvsi_console_setup,
1172         .flags          = CON_PRINTBUFFER,
1173         .index          = -1,
1174 };
1175
1176 static int __init hvsi_console_init(void)
1177 {
1178         struct device_node *vty;
1179
1180         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1181
1182         /* search device tree for vty nodes */
1183         for_each_compatible_node(vty, "serial", "hvterm-protocol") {
1184                 struct hvsi_struct *hp;
1185                 const __be32 *vtermno, *irq;
1186
1187                 vtermno = of_get_property(vty, "reg", NULL);
1188                 irq = of_get_property(vty, "interrupts", NULL);
1189                 if (!vtermno || !irq)
1190                         continue;
1191
1192                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1193                         of_node_put(vty);
1194                         break;
1195                 }
1196
1197                 hp = &hvsi_ports[hvsi_count];
1198                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1199                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1200                 init_waitqueue_head(&hp->emptyq);
1201                 init_waitqueue_head(&hp->stateq);
1202                 spin_lock_init(&hp->lock);
1203                 tty_port_init(&hp->port);
1204                 hp->index = hvsi_count;
1205                 hp->inbuf_end = hp->inbuf;
1206                 hp->state = HVSI_CLOSED;
1207                 hp->vtermno = be32_to_cpup(vtermno);
1208                 hp->virq = irq_create_mapping(NULL, be32_to_cpup(irq));
1209                 if (hp->virq == 0) {
1210                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1211                                __func__, be32_to_cpup(irq));
1212                         tty_port_destroy(&hp->port);
1213                         continue;
1214                 }
1215
1216                 hvsi_count++;
1217         }
1218
1219         if (hvsi_count)
1220                 register_console(&hvsi_console);
1221         return 0;
1222 }
1223 console_initcall(hvsi_console_init);