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 delayed_work writer;
  73         struct work_struct handshaker;
  74         wait_queue_head_t emptyq; /* woken when outbuf is emptied */
  75         wait_queue_head_t stateq; /* woken when HVSI state changes */
  76         spinlock_t lock;
  77         int index;
  78         struct tty_struct *tty;
  79         int count;
  80         uint8_t throttle_buf[128];
  81         uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
  82         /* inbuf is for packet reassembly. leave a little room for leftovers. */
  83         uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
  84         uint8_t *inbuf_end;
  85         int n_throttle;
  86         int n_outbuf;
  87         uint32_t vtermno;
  88         uint32_t virq;
  89         atomic_t seqno; /* HVSI packet sequence number */
  90         uint16_t mctrl;
  91         uint8_t state;  /* HVSI protocol state */
  92         uint8_t flags;
  93 #ifdef CONFIG_MAGIC_SYSRQ
  94         uint8_t sysrq;
  95 #endif /* CONFIG_MAGIC_SYSRQ */
  96 };
  97 static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
  98
  99 static struct tty_driver *hvsi_driver;
 100 static int hvsi_count;
 101 static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
 102
 103 enum HVSI_PROTOCOL_STATE {
 104         HVSI_CLOSED,
 105         HVSI_WAIT_FOR_VER_RESPONSE,
 106         HVSI_WAIT_FOR_VER_QUERY,
 107         HVSI_OPEN,
 108         HVSI_WAIT_FOR_MCTRL_RESPONSE,
 109         HVSI_FSP_DIED,
 110 };
 111 #define HVSI_CONSOLE 0x1
 112
 113 static inline int is_console(struct hvsi_struct *hp)
 114 {
 115         return hp->flags & HVSI_CONSOLE;
 116 }
 117
 118 static inline int is_open(struct hvsi_struct *hp)
 119 {
 120         /* if we're waiting for an mctrl then we're already open */
 121         return (hp->state == HVSI_OPEN)
 122                         || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
 123 }
 124
 125 static inline void print_state(struct hvsi_struct *hp)
 126 {
 127 #ifdef DEBUG
 128         static const char *state_names[] = {
 129                 "HVSI_CLOSED",
 130                 "HVSI_WAIT_FOR_VER_RESPONSE",
 131                 "HVSI_WAIT_FOR_VER_QUERY",
 132                 "HVSI_OPEN",
 133                 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
 134                 "HVSI_FSP_DIED",
 135         };
 136         const char *name = (hp->state < ARRAY_SIZE(state_names))
 137                 ? state_names[hp->state] : "UNKNOWN";
 138
 139         pr_debug("hvsi%i: state = %s\n", hp->index, name);
 140 #endif /* DEBUG */
 141 }
 142
 143 static inline void __set_state(struct hvsi_struct *hp, int state)
 144 {
 145         hp->state = state;
 146         print_state(hp);
 147         wake_up_all(&hp->stateq);
 148 }
 149
 150 static inline void set_state(struct hvsi_struct *hp, int state)
 151 {
 152         unsigned long flags;
 153
 154         spin_lock_irqsave(&hp->lock, flags);
 155         __set_state(hp, state);
 156         spin_unlock_irqrestore(&hp->lock, flags);
 157 }
 158
 159 static inline int len_packet(const uint8_t *packet)
 160 {
 161         return (int)((struct hvsi_header *)packet)->len;
 162 }
 163
 164 static inline int is_header(const uint8_t *packet)
 165 {
 166         struct hvsi_header *header = (struct hvsi_header *)packet;
 167         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
 168 }
 169
 170 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
 171 {
 172         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
 173                 return 0; /* don't even have the packet header */
 174
 175         if (hp->inbuf_end < (packet + len_packet(packet)))
 176                 return 0; /* don't have the rest of the packet */
 177
 178         return 1;
 179 }
 180
 181 /* shift remaining bytes in packetbuf down */
 182 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
 183 {
 184         int remaining = (int)(hp->inbuf_end - read_to);
 185
 186         pr_debug("%s: %i chars remain\n", __func__, remaining);
 187
 188         if (read_to != hp->inbuf)
 189                 memmove(hp->inbuf, read_to, remaining);
 190
 191         hp->inbuf_end = hp->inbuf + remaining;
 192 }
 193
 194 #ifdef DEBUG
 195 #define dbg_dump_packet(packet) dump_packet(packet)
 196 #define dbg_dump_hex(data, len) dump_hex(data, len)
 197 #else
 198 #define dbg_dump_packet(packet) do { } while (0)
 199 #define dbg_dump_hex(data, len) do { } while (0)
 200 #endif
 201
 202 static void dump_hex(const uint8_t *data, int len)
 203 {
 204         int i;
 205
 206         printk("    ");
 207         for (i=0; i < len; i++)
 208                 printk("%.2x", data[i]);
 209
 210         printk("\n    ");
 211         for (i=0; i < len; i++) {
 212                 if (isprint(data[i]))
 213                         printk("%c", data[i]);
 214                 else
 215                         printk(".");
 216         }
 217         printk("\n");
 218 }
 219
 220 static void dump_packet(uint8_t *packet)
 221 {
 222         struct hvsi_header *header = (struct hvsi_header *)packet;
 223
 224         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
 225                         header->seqno);
 226
 227         dump_hex(packet, header->len);
 228 }
 229
 230 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
 231 {
 232         unsigned long got;
 233
 234         got = hvc_get_chars(hp->vtermno, buf, count);
 235
 236         return got;
 237 }
 238
 239 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
 240         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
 241 {
 242         struct hvsi_control *header = (struct hvsi_control *)packet;
 243
 244         switch (header->verb) {
 245                 case VSV_MODEM_CTL_UPDATE:
 246                         if ((header->word & HVSI_TSCD) == 0) {
 247                                 /* CD went away; no more connection */
 248                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
 249                                 hp->mctrl &= TIOCM_CD;
 250                                 /* If userland hasn't done an open(2) yet, hp->tty is NULL. */
 251                                 if (hp->tty && !(hp->tty->flags & CLOCAL))
 252                                         *to_hangup = hp->tty;
 253                         }
 254                         break;
 255                 case VSV_CLOSE_PROTOCOL:
 256                         pr_debug("hvsi%i: service processor came back\n", hp->index);
 257                         if (hp->state != HVSI_CLOSED) {
 258                                 *to_handshake = hp;
 259                         }
 260                         break;
 261                 default:
 262                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
 263                                 hp->index);
 264                         dump_packet(packet);
 265                         break;
 266         }
 267 }
 268
 269 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
 270 {
 271         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
 272
 273         switch (hp->state) {
 274                 case HVSI_WAIT_FOR_VER_RESPONSE:
 275                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
 276                         break;
 277                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
 278                         hp->mctrl = 0;
 279                         if (resp->u.mctrl_word & HVSI_TSDTR)
 280                                 hp->mctrl |= TIOCM_DTR;
 281                         if (resp->u.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 = atomic_inc_return(&hp->seqno);
 301         packet.verb = VSV_SEND_VERSION_NUMBER;
 302         packet.u.version = HVSI_VERSION;
 303         packet.query_seqno = 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, 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->tty, 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 struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
 364                 const uint8_t *packet)
 365 {
 366         const struct hvsi_header *header = (const struct hvsi_header *)packet;
 367         const uint8_t *data = packet + sizeof(struct hvsi_header);
 368         int datalen = header->len - sizeof(struct hvsi_header);
 369         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
 370
 371         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
 372
 373         if (datalen == 0)
 374                 return NULL;
 375
 376         if (overflow > 0) {
 377                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
 378                 datalen = TTY_THRESHOLD_THROTTLE;
 379         }
 380
 381         hvsi_insert_chars(hp, data, datalen);
 382
 383         if (overflow > 0) {
 384                 /*
 385                  * we still have more data to deliver, so we need to save off the
 386                  * overflow and send it later
 387                  */
 388                 pr_debug("%s: deferring overflow\n", __func__);
 389                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
 390                 hp->n_throttle = overflow;
 391         }
 392
 393         return hp->tty;
 394 }
 395
 396 /*
 397  * Returns true/false indicating data successfully read from hypervisor.
 398  * Used both to get packets for tty connections and to advance the state
 399  * machine during console handshaking (in which case tty = NULL and we ignore
 400  * incoming data).
 401  */
 402 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
 403                 struct tty_struct **hangup, struct hvsi_struct **handshake)
 404 {
 405         uint8_t *packet = hp->inbuf;
 406         int chunklen;
 407
 408         *flip = NULL;
 409         *hangup = NULL;
 410         *handshake = NULL;
 411
 412         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
 413         if (chunklen == 0) {
 414                 pr_debug("%s: 0-length read\n", __func__);
 415                 return 0;
 416         }
 417
 418         pr_debug("%s: got %i bytes\n", __func__, chunklen);
 419         dbg_dump_hex(hp->inbuf_end, chunklen);
 420
 421         hp->inbuf_end += chunklen;
 422
 423         /* handle all completed packets */
 424         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
 425                 struct hvsi_header *header = (struct hvsi_header *)packet;
 426
 427                 if (!is_header(packet)) {
 428                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
 429                         /* skip bytes until we find a header or run out of data */
 430                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
 431                                 packet++;
 432                         continue;
 433                 }
 434
 435                 pr_debug("%s: handling %i-byte packet\n", __func__,
 436                                 len_packet(packet));
 437                 dbg_dump_packet(packet);
 438
 439                 switch (header->type) {
 440                         case VS_DATA_PACKET_HEADER:
 441                                 if (!is_open(hp))
 442                                         break;
 443                                 if (hp->tty == NULL)
 444                                         break; /* no tty buffer to put data in */
 445                                 *flip = hvsi_recv_data(hp, packet);
 446                                 break;
 447                         case VS_CONTROL_PACKET_HEADER:
 448                                 hvsi_recv_control(hp, packet, hangup, handshake);
 449                                 break;
 450                         case VS_QUERY_RESPONSE_PACKET_HEADER:
 451                                 hvsi_recv_response(hp, packet);
 452                                 break;
 453                         case VS_QUERY_PACKET_HEADER:
 454                                 hvsi_recv_query(hp, packet);
 455                                 break;
 456                         default:
 457                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
 458                                                 hp->index, header->type);
 459                                 dump_packet(packet);
 460                                 break;
 461                 }
 462
 463                 packet += len_packet(packet);
 464
 465                 if (*hangup || *handshake) {
 466                         pr_debug("%s: hangup or handshake\n", __func__);
 467                         /*
 468                          * we need to send the hangup now before receiving any more data.
 469                          * If we get "data, hangup, data", we can't deliver the second
 470                          * data before the hangup.
 471                          */
 472                         break;
 473                 }
 474         }
 475
 476         compact_inbuf(hp, packet);
 477
 478         return 1;
 479 }
 480
 481 static void hvsi_send_overflow(struct hvsi_struct *hp)
 482 {
 483         pr_debug("%s: delivering %i bytes overflow\n", __func__,
 484                         hp->n_throttle);
 485
 486         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
 487         hp->n_throttle = 0;
 488 }
 489
 490 /*
 491  * must get all pending data because we only get an irq on empty->non-empty
 492  * transition
 493  */
 494 static irqreturn_t hvsi_interrupt(int irq, void *arg)
 495 {
 496         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 497         struct tty_struct *flip;
 498         struct tty_struct *hangup;
 499         struct hvsi_struct *handshake;
 500         unsigned long flags;
 501         int again = 1;
 502
 503         pr_debug("%s\n", __func__);
 504
 505         while (again) {
 506                 spin_lock_irqsave(&hp->lock, flags);
 507                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
 508                 spin_unlock_irqrestore(&hp->lock, flags);
 509
 510                 /*
 511                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
 512                  * spinlock. But we also have to keep going until we've read all the
 513                  * available data.
 514                  */
 515
 516                 if (flip) {
 517                         /* there was data put in the tty flip buffer */
 518                         tty_flip_buffer_push(flip);
 519                         flip = NULL;
 520                 }
 521
 522                 if (hangup) {
 523                         tty_hangup(hangup);
 524                 }
 525
 526                 if (handshake) {
 527                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
 528                         schedule_work(&handshake->handshaker);
 529                 }
 530         }
 531
 532         spin_lock_irqsave(&hp->lock, flags);
 533         if (hp->tty && hp->n_throttle
 534                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
 535                 /* we weren't hung up and we weren't throttled, so we can deliver the
 536                  * rest now */
 537                 flip = hp->tty;
 538                 hvsi_send_overflow(hp);
 539         }
 540         spin_unlock_irqrestore(&hp->lock, flags);
 541
 542         if (flip) {
 543                 tty_flip_buffer_push(flip);
 544         }
 545
 546         return IRQ_HANDLED;
 547 }
 548
 549 /* for boot console, before the irq handler is running */
 550 static int __init poll_for_state(struct hvsi_struct *hp, int state)
 551 {
 552         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 553
 554         for (;;) {
 555                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
 556
 557                 if (hp->state == state)
 558                         return 0;
 559
 560                 mdelay(5);
 561                 if (time_after(jiffies, end_jiffies))
 562                         return -EIO;
 563         }
 564 }
 565
 566 /* wait for irq handler to change our state */
 567 static int wait_for_state(struct hvsi_struct *hp, int state)
 568 {
 569         int ret = 0;
 570
 571         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
 572                 ret = -EIO;
 573
 574         return ret;
 575 }
 576
 577 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
 578 {
 579         struct hvsi_query packet __ALIGNED__;
 580         int wrote;
 581
 582         packet.hdr.type = VS_QUERY_PACKET_HEADER;
 583         packet.hdr.len = sizeof(struct hvsi_query);
 584         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
 585         packet.verb = verb;
 586
 587         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 588         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 589
 590         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 591         if (wrote != packet.hdr.len) {
 592                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
 593                         wrote);
 594                 return -EIO;
 595         }
 596
 597         return 0;
 598 }
 599
 600 static int hvsi_get_mctrl(struct hvsi_struct *hp)
 601 {
 602         int ret;
 603
 604         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
 605         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
 606
 607         ret = hvsi_wait(hp, HVSI_OPEN);
 608         if (ret < 0) {
 609                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
 610                 set_state(hp, HVSI_OPEN);
 611                 return ret;
 612         }
 613
 614         pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
 615
 616         return 0;
 617 }
 618
 619 /* note that we can only set DTR */
 620 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
 621 {
 622         struct hvsi_control packet __ALIGNED__;
 623         int wrote;
 624
 625         packet.hdr.type = VS_CONTROL_PACKET_HEADER,
 626         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
 627         packet.hdr.len = sizeof(struct hvsi_control);
 628         packet.verb = VSV_SET_MODEM_CTL;
 629         packet.mask = HVSI_TSDTR;
 630
 631         if (mctrl & TIOCM_DTR)
 632                 packet.word = HVSI_TSDTR;
 633
 634         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 635         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 636
 637         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 638         if (wrote != packet.hdr.len) {
 639                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
 640                 return -EIO;
 641         }
 642
 643         return 0;
 644 }
 645
 646 static void hvsi_drain_input(struct hvsi_struct *hp)
 647 {
 648         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
 649         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 650
 651         while (time_before(end_jiffies, jiffies))
 652                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
 653                         break;
 654 }
 655
 656 static int hvsi_handshake(struct hvsi_struct *hp)
 657 {
 658         int ret;
 659
 660         /*
 661          * We could have a CLOSE or other data waiting for us before we even try
 662          * to open; try to throw it all away so we don't get confused. (CLOSE
 663          * is the first message sent up the pipe when the FSP comes online. We
 664          * need to distinguish between "it came up a while ago and we're the first
 665          * user" and "it was just reset before it saw our handshake packet".)
 666          */
 667         hvsi_drain_input(hp);
 668
 669         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
 670         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
 671         if (ret < 0) {
 672                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
 673                 return ret;
 674         }
 675
 676         ret = hvsi_wait(hp, HVSI_OPEN);
 677         if (ret < 0)
 678                 return ret;
 679
 680         return 0;
 681 }
 682
 683 static void hvsi_handshaker(struct work_struct *work)
 684 {
 685         struct hvsi_struct *hp =
 686                 container_of(work, struct hvsi_struct, handshaker);
 687
 688         if (hvsi_handshake(hp) >= 0)
 689                 return;
 690
 691         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
 692         if (is_console(hp)) {
 693                 /*
 694                  * ttys will re-attempt the handshake via hvsi_open, but
 695                  * the console will not.
 696                  */
 697                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
 698         }
 699 }
 700
 701 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
 702 {
 703         struct hvsi_data packet __ALIGNED__;
 704         int ret;
 705
 706         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
 707
 708         packet.hdr.type = VS_DATA_PACKET_HEADER;
 709         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
 710         packet.hdr.len = count + sizeof(struct hvsi_header);
 711         memcpy(&packet.data, buf, count);
 712
 713         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 714         if (ret == packet.hdr.len) {
 715                 /* return the number of chars written, not the packet length */
 716                 return count;
 717         }
 718         return ret; /* return any errors */
 719 }
 720
 721 static void hvsi_close_protocol(struct hvsi_struct *hp)
 722 {
 723         struct hvsi_control packet __ALIGNED__;
 724
 725         packet.hdr.type = VS_CONTROL_PACKET_HEADER;
 726         packet.hdr.seqno = atomic_inc_return(&hp->seqno);
 727         packet.hdr.len = 6;
 728         packet.verb = VSV_CLOSE_PROTOCOL;
 729
 730         pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len);
 731         dbg_dump_hex((uint8_t*)&packet, packet.hdr.len);
 732
 733         hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len);
 734 }
 735
 736 static int hvsi_open(struct tty_struct *tty, struct file *filp)
 737 {
 738         struct hvsi_struct *hp;
 739         unsigned long flags;
 740         int line = tty->index;
 741         int ret;
 742
 743         pr_debug("%s\n", __func__);
 744
 745         if (line < 0 || line >= hvsi_count)
 746                 return -ENODEV;
 747         hp = &hvsi_ports[line];
 748
 749         tty->driver_data = hp;
 750
 751         mb();
 752         if (hp->state == HVSI_FSP_DIED)
 753                 return -EIO;
 754
 755         spin_lock_irqsave(&hp->lock, flags);
 756         hp->tty = tty;
 757         hp->count++;
 758         atomic_set(&hp->seqno, 0);
 759         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
 760         spin_unlock_irqrestore(&hp->lock, flags);
 761
 762         if (is_console(hp))
 763                 return 0; /* this has already been handshaked as the console */
 764
 765         ret = hvsi_handshake(hp);
 766         if (ret < 0) {
 767                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
 768                 return ret;
 769         }
 770
 771         ret = hvsi_get_mctrl(hp);
 772         if (ret < 0) {
 773                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
 774                 return ret;
 775         }
 776
 777         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
 778         if (ret < 0) {
 779                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
 780                 return ret;
 781         }
 782
 783         return 0;
 784 }
 785
 786 /* wait for hvsi_write_worker to empty hp->outbuf */
 787 static void hvsi_flush_output(struct hvsi_struct *hp)
 788 {
 789         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
 790
 791         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
 792         cancel_delayed_work_sync(&hp->writer);
 793         flush_work_sync(&hp->handshaker);
 794
 795         /*
 796          * it's also possible that our timeout expired and hvsi_write_worker
 797          * didn't manage to push outbuf. poof.
 798          */
 799         hp->n_outbuf = 0;
 800 }
 801
 802 static void hvsi_close(struct tty_struct *tty, struct file *filp)
 803 {
 804         struct hvsi_struct *hp = tty->driver_data;
 805         unsigned long flags;
 806
 807         pr_debug("%s\n", __func__);
 808
 809         if (tty_hung_up_p(filp))
 810                 return;
 811
 812         spin_lock_irqsave(&hp->lock, flags);
 813
 814         if (--hp->count == 0) {
 815                 hp->tty = NULL;
 816                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
 817
 818                 /* only close down connection if it is not the console */
 819                 if (!is_console(hp)) {
 820                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
 821                         __set_state(hp, HVSI_CLOSED);
 822                         /*
 823                          * any data delivered to the tty layer after this will be
 824                          * discarded (except for XON/XOFF)
 825                          */
 826                         tty->closing = 1;
 827
 828                         spin_unlock_irqrestore(&hp->lock, flags);
 829
 830                         /* let any existing irq handlers finish. no more will start. */
 831                         synchronize_irq(hp->virq);
 832
 833                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
 834                         hvsi_flush_output(hp);
 835
 836                         /* tell FSP to stop sending data */
 837                         hvsi_close_protocol(hp);
 838
 839                         /*
 840                          * drain anything FSP is still in the middle of sending, and let
 841                          * hvsi_handshake drain the rest on the next open.
 842                          */
 843                         hvsi_drain_input(hp);
 844
 845                         spin_lock_irqsave(&hp->lock, flags);
 846                 }
 847         } else if (hp->count < 0)
 848                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
 849                        hp - hvsi_ports, hp->count);
 850
 851         spin_unlock_irqrestore(&hp->lock, flags);
 852 }
 853
 854 static void hvsi_hangup(struct tty_struct *tty)
 855 {
 856         struct hvsi_struct *hp = tty->driver_data;
 857         unsigned long flags;
 858
 859         pr_debug("%s\n", __func__);
 860
 861         spin_lock_irqsave(&hp->lock, flags);
 862
 863         hp->count = 0;
 864         hp->n_outbuf = 0;
 865         hp->tty = NULL;
 866
 867         spin_unlock_irqrestore(&hp->lock, flags);
 868 }
 869
 870 /* called with hp->lock held */
 871 static void hvsi_push(struct hvsi_struct *hp)
 872 {
 873         int n;
 874
 875         if (hp->n_outbuf <= 0)
 876                 return;
 877
 878         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
 879         if (n > 0) {
 880                 /* success */
 881                 pr_debug("%s: wrote %i chars\n", __func__, n);
 882                 hp->n_outbuf = 0;
 883         } else if (n == -EIO) {
 884                 __set_state(hp, HVSI_FSP_DIED);
 885                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
 886         }
 887 }
 888
 889 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
 890 static void hvsi_write_worker(struct work_struct *work)
 891 {
 892         struct hvsi_struct *hp =
 893                 container_of(work, struct hvsi_struct, writer.work);
 894         unsigned long flags;
 895 #ifdef DEBUG
 896         static long start_j = 0;
 897
 898         if (start_j == 0)
 899                 start_j = jiffies;
 900 #endif /* DEBUG */
 901
 902         spin_lock_irqsave(&hp->lock, flags);
 903
 904         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
 905
 906         if (!is_open(hp)) {
 907                 /*
 908                  * We could have a non-open connection if the service processor died
 909                  * while we were busily scheduling ourselves. In that case, it could
 910                  * be minutes before the service processor comes back, so only try
 911                  * again once a second.
 912                  */
 913                 schedule_delayed_work(&hp->writer, HZ);
 914                 goto out;
 915         }
 916
 917         hvsi_push(hp);
 918         if (hp->n_outbuf > 0)
 919                 schedule_delayed_work(&hp->writer, 10);
 920         else {
 921 #ifdef DEBUG
 922                 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
 923                                 jiffies - start_j);
 924                 start_j = 0;
 925 #endif /* DEBUG */
 926                 wake_up_all(&hp->emptyq);
 927                 tty_wakeup(hp->tty);
 928         }
 929
 930 out:
 931         spin_unlock_irqrestore(&hp->lock, flags);
 932 }
 933
 934 static int hvsi_write_room(struct tty_struct *tty)
 935 {
 936         struct hvsi_struct *hp = tty->driver_data;
 937
 938         return N_OUTBUF - hp->n_outbuf;
 939 }
 940
 941 static int hvsi_chars_in_buffer(struct tty_struct *tty)
 942 {
 943         struct hvsi_struct *hp = tty->driver_data;
 944
 945         return hp->n_outbuf;
 946 }
 947
 948 static int hvsi_write(struct tty_struct *tty,
 949                      const unsigned char *buf, int count)
 950 {
 951         struct hvsi_struct *hp = tty->driver_data;
 952         const char *source = buf;
 953         unsigned long flags;
 954         int total = 0;
 955         int origcount = count;
 956
 957         spin_lock_irqsave(&hp->lock, flags);
 958
 959         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
 960
 961         if (!is_open(hp)) {
 962                 /* we're either closing or not yet open; don't accept data */
 963                 pr_debug("%s: not open\n", __func__);
 964                 goto out;
 965         }
 966
 967         /*
 968          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
 969          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
 970          * will see there is no room in outbuf and return.
 971          */
 972         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
 973                 int chunksize = min(count, hvsi_write_room(hp->tty));
 974
 975                 BUG_ON(hp->n_outbuf < 0);
 976                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
 977                 hp->n_outbuf += chunksize;
 978
 979                 total += chunksize;
 980                 source += chunksize;
 981                 count -= chunksize;
 982                 hvsi_push(hp);
 983         }
 984
 985         if (hp->n_outbuf > 0) {
 986                 /*
 987                  * we weren't able to write it all to the hypervisor.
 988                  * schedule another push attempt.
 989                  */
 990                 schedule_delayed_work(&hp->writer, 10);
 991         }
 992
 993 out:
 994         spin_unlock_irqrestore(&hp->lock, flags);
 995
 996         if (total != origcount)
 997                 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
 998                         total);
 999
1000         return total;
1001 }
1002
1003 /*
1004  * I have never seen throttle or unthrottle called, so this little throttle
1005  * buffering scheme may or may not work.
1006  */
1007 static void hvsi_throttle(struct tty_struct *tty)
1008 {
1009         struct hvsi_struct *hp = tty->driver_data;
1010
1011         pr_debug("%s\n", __func__);
1012
1013         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1014 }
1015
1016 static void hvsi_unthrottle(struct tty_struct *tty)
1017 {
1018         struct hvsi_struct *hp = tty->driver_data;
1019         unsigned long flags;
1020         int shouldflip = 0;
1021
1022         pr_debug("%s\n", __func__);
1023
1024         spin_lock_irqsave(&hp->lock, flags);
1025         if (hp->n_throttle) {
1026                 hvsi_send_overflow(hp);
1027                 shouldflip = 1;
1028         }
1029         spin_unlock_irqrestore(&hp->lock, flags);
1030
1031         if (shouldflip)
1032                 tty_flip_buffer_push(hp->tty);
1033
1034         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1035 }
1036
1037 static int hvsi_tiocmget(struct tty_struct *tty)
1038 {
1039         struct hvsi_struct *hp = tty->driver_data;
1040
1041         hvsi_get_mctrl(hp);
1042         return hp->mctrl;
1043 }
1044
1045 static int hvsi_tiocmset(struct tty_struct *tty,
1046                                 unsigned int set, unsigned int clear)
1047 {
1048         struct hvsi_struct *hp = tty->driver_data;
1049         unsigned long flags;
1050         uint16_t new_mctrl;
1051
1052         /* we can only alter DTR */
1053         clear &= TIOCM_DTR;
1054         set &= TIOCM_DTR;
1055
1056         spin_lock_irqsave(&hp->lock, flags);
1057
1058         new_mctrl = (hp->mctrl & ~clear) | set;
1059
1060         if (hp->mctrl != new_mctrl) {
1061                 hvsi_set_mctrl(hp, new_mctrl);
1062                 hp->mctrl = new_mctrl;
1063         }
1064         spin_unlock_irqrestore(&hp->lock, flags);
1065
1066         return 0;
1067 }
1068
1069
1070 static const struct tty_operations hvsi_ops = {
1071         .open = hvsi_open,
1072         .close = hvsi_close,
1073         .write = hvsi_write,
1074         .hangup = hvsi_hangup,
1075         .write_room = hvsi_write_room,
1076         .chars_in_buffer = hvsi_chars_in_buffer,
1077         .throttle = hvsi_throttle,
1078         .unthrottle = hvsi_unthrottle,
1079         .tiocmget = hvsi_tiocmget,
1080         .tiocmset = hvsi_tiocmset,
1081 };
1082
1083 static int __init hvsi_init(void)
1084 {
1085         int i;
1086
1087         hvsi_driver = alloc_tty_driver(hvsi_count);
1088         if (!hvsi_driver)
1089                 return -ENOMEM;
1090
1091         hvsi_driver->owner = THIS_MODULE;
1092         hvsi_driver->driver_name = "hvsi";
1093         hvsi_driver->name = "hvsi";
1094         hvsi_driver->major = HVSI_MAJOR;
1095         hvsi_driver->minor_start = HVSI_MINOR;
1096         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1097         hvsi_driver->init_termios = tty_std_termios;
1098         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1099         hvsi_driver->init_termios.c_ispeed = 9600;
1100         hvsi_driver->init_termios.c_ospeed = 9600;
1101         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1102         tty_set_operations(hvsi_driver, &hvsi_ops);
1103
1104         for (i=0; i < hvsi_count; i++) {
1105                 struct hvsi_struct *hp = &hvsi_ports[i];
1106                 int ret = 1;
1107
1108                 ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp);
1109                 if (ret)
1110                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1111                                 hp->virq, ret);
1112         }
1113         hvsi_wait = wait_for_state; /* irqs active now */
1114
1115         if (tty_register_driver(hvsi_driver))
1116                 panic("Couldn't register hvsi console driver\n");
1117
1118         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1119
1120         return 0;
1121 }
1122 device_initcall(hvsi_init);
1123
1124 /***** console (not tty) code: *****/
1125
1126 static void hvsi_console_print(struct console *console, const char *buf,
1127                 unsigned int count)
1128 {
1129         struct hvsi_struct *hp = &hvsi_ports[console->index];
1130         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1131         unsigned int i = 0, n = 0;
1132         int ret, donecr = 0;
1133
1134         mb();
1135         if (!is_open(hp))
1136                 return;
1137
1138         /*
1139          * ugh, we have to translate LF -> CRLF ourselves, in place.
1140          * copied from hvc_console.c:
1141          */
1142         while (count > 0 || i > 0) {
1143                 if (count > 0 && i < sizeof(c)) {
1144                         if (buf[n] == '\n' && !donecr) {
1145                                 c[i++] = '\r';
1146                                 donecr = 1;
1147                         } else {
1148                                 c[i++] = buf[n++];
1149                                 donecr = 0;
1150                                 --count;
1151                         }
1152                 } else {
1153                         ret = hvsi_put_chars(hp, c, i);
1154                         if (ret < 0)
1155                                 i = 0;
1156                         i -= ret;
1157                 }
1158         }
1159 }
1160
1161 static struct tty_driver *hvsi_console_device(struct console *console,
1162         int *index)
1163 {
1164         *index = console->index;
1165         return hvsi_driver;
1166 }
1167
1168 static int __init hvsi_console_setup(struct console *console, char *options)
1169 {
1170         struct hvsi_struct *hp;
1171         int ret;
1172
1173         if (console->index < 0 || console->index >= hvsi_count)
1174                 return -1;
1175         hp = &hvsi_ports[console->index];
1176
1177         /* give the FSP a chance to change the baud rate when we re-open */
1178         hvsi_close_protocol(hp);
1179
1180         ret = hvsi_handshake(hp);
1181         if (ret < 0)
1182                 return ret;
1183
1184         ret = hvsi_get_mctrl(hp);
1185         if (ret < 0)
1186                 return ret;
1187
1188         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1189         if (ret < 0)
1190                 return ret;
1191
1192         hp->flags |= HVSI_CONSOLE;
1193
1194         return 0;
1195 }
1196
1197 static struct console hvsi_console = {
1198         .name           = "hvsi",
1199         .write          = hvsi_console_print,
1200         .device         = hvsi_console_device,
1201         .setup          = hvsi_console_setup,
1202         .flags          = CON_PRINTBUFFER,
1203         .index          = -1,
1204 };
1205
1206 static int __init hvsi_console_init(void)
1207 {
1208         struct device_node *vty;
1209
1210         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1211
1212         /* search device tree for vty nodes */
1213         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1214                         vty != NULL;
1215                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1216                 struct hvsi_struct *hp;
1217                 const uint32_t *vtermno, *irq;
1218
1219                 vtermno = of_get_property(vty, "reg", NULL);
1220                 irq = of_get_property(vty, "interrupts", NULL);
1221                 if (!vtermno || !irq)
1222                         continue;
1223
1224                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1225                         of_node_put(vty);
1226                         break;
1227                 }
1228
1229                 hp = &hvsi_ports[hvsi_count];
1230                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1231                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1232                 init_waitqueue_head(&hp->emptyq);
1233                 init_waitqueue_head(&hp->stateq);
1234                 spin_lock_init(&hp->lock);
1235                 hp->index = hvsi_count;
1236                 hp->inbuf_end = hp->inbuf;
1237                 hp->state = HVSI_CLOSED;
1238                 hp->vtermno = *vtermno;
1239                 hp->virq = irq_create_mapping(NULL, irq[0]);
1240                 if (hp->virq == NO_IRQ) {
1241                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1242                                 __func__, irq[0]);
1243                         continue;
1244                 }
1245
1246                 hvsi_count++;
1247         }
1248
1249         if (hvsi_count)
1250                 register_console(&hvsi_console);
1251         return 0;
1252 }
1253 console_initcall(hvsi_console_init);