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