git.oblomov.eu Git - linux-2.6/blob - drivers/char/hvsi.c

   1 /*
   2  * Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  17  */
  18
  19 /* Host Virtual Serial Interface (HVSI) is a protocol between the hosted OS
  20  * and the service processor on IBM pSeries servers. On these servers, there
  21  * are no serial ports under the OS's control, and sometimes there is no other
  22  * console available either. However, the service processor has two standard
  23  * serial ports, so this over-complicated protocol allows the OS to control
  24  * those ports by proxy.
  25  *
  26  * Besides data, the procotol supports the reading/writing of the serial
  27  * port's DTR line, and the reading of the CD line. This is to allow the OS to
  28  * control a modem attached to the service processor's serial port. Note that
  29  * the OS cannot change the speed of the port through this protocol.
  30  */
  31
  32 #undef DEBUG
  33
  34 #include <linux/console.h>
  35 #include <linux/ctype.h>
  36 #include <linux/delay.h>
  37 #include <linux/init.h>
  38 #include <linux/interrupt.h>
  39 #include <linux/module.h>
  40 #include <linux/major.h>
  41 #include <linux/kernel.h>
  42 #include <linux/spinlock.h>
  43 #include <linux/sysrq.h>
  44 #include <linux/tty.h>
  45 #include <linux/tty_flip.h>
  46 #include <asm/hvcall.h>
  47 #include <asm/hvconsole.h>
  48 #include <asm/prom.h>
  49 #include <asm/uaccess.h>
  50 #include <asm/vio.h>
  51 #include <asm/param.h>
  52
  53 #define HVSI_MAJOR      229
  54 #define HVSI_MINOR      128
  55 #define MAX_NR_HVSI_CONSOLES 4
  56
  57 #define HVSI_TIMEOUT (5*HZ)
  58 #define HVSI_VERSION 1
  59 #define HVSI_MAX_PACKET 256
  60 #define HVSI_MAX_READ 16
  61 #define HVSI_MAX_OUTGOING_DATA 12
  62 #define N_OUTBUF 12
  63
  64 /*
  65  * we pass data via two 8-byte registers, so we would like our char arrays
  66  * properly aligned for those loads.
  67  */
  68 #define __ALIGNED__     __attribute__((__aligned__(sizeof(long))))
  69
  70 struct hvsi_struct {
  71         struct delayed_work writer;
  72         struct work_struct handshaker;
  73         wait_queue_head_t emptyq; /* woken when outbuf is emptied */
  74         wait_queue_head_t stateq; /* woken when HVSI state changes */
  75         spinlock_t lock;
  76         int index;
  77         struct tty_struct *tty;
  78         int count;
  79         uint8_t throttle_buf[128];
  80         uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
  81         /* inbuf is for packet reassembly. leave a little room for leftovers. */
  82         uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
  83         uint8_t *inbuf_end;
  84         int n_throttle;
  85         int n_outbuf;
  86         uint32_t vtermno;
  87         uint32_t virq;
  88         atomic_t seqno; /* HVSI packet sequence number */
  89         uint16_t mctrl;
  90         uint8_t state;  /* HVSI protocol state */
  91         uint8_t flags;
  92 #ifdef CONFIG_MAGIC_SYSRQ
  93         uint8_t sysrq;
  94 #endif /* CONFIG_MAGIC_SYSRQ */
  95 };
  96 static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
  97
  98 static struct tty_driver *hvsi_driver;
  99 static int hvsi_count;
 100 static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
 101
 102 enum HVSI_PROTOCOL_STATE {
 103         HVSI_CLOSED,
 104         HVSI_WAIT_FOR_VER_RESPONSE,
 105         HVSI_WAIT_FOR_VER_QUERY,
 106         HVSI_OPEN,
 107         HVSI_WAIT_FOR_MCTRL_RESPONSE,
 108         HVSI_FSP_DIED,
 109 };
 110 #define HVSI_CONSOLE 0x1
 111
 112 #define VS_DATA_PACKET_HEADER           0xff
 113 #define VS_CONTROL_PACKET_HEADER        0xfe
 114 #define VS_QUERY_PACKET_HEADER          0xfd
 115 #define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc
 116
 117 /* control verbs */
 118 #define VSV_SET_MODEM_CTL    1 /* to service processor only */
 119 #define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */
 120 #define VSV_CLOSE_PROTOCOL   3
 121
 122 /* query verbs */
 123 #define VSV_SEND_VERSION_NUMBER 1
 124 #define VSV_SEND_MODEM_CTL_STATUS 2
 125
 126 /* yes, these masks are not consecutive. */
 127 #define HVSI_TSDTR 0x01
 128 #define HVSI_TSCD  0x20
 129
 130 struct hvsi_header {
 131         uint8_t  type;
 132         uint8_t  len;
 133         uint16_t seqno;
 134 } __attribute__((packed));
 135
 136 struct hvsi_data {
 137         uint8_t  type;
 138         uint8_t  len;
 139         uint16_t seqno;
 140         uint8_t  data[HVSI_MAX_OUTGOING_DATA];
 141 } __attribute__((packed));
 142
 143 struct hvsi_control {
 144         uint8_t  type;
 145         uint8_t  len;
 146         uint16_t seqno;
 147         uint16_t verb;
 148         /* optional depending on verb: */
 149         uint32_t word;
 150         uint32_t mask;
 151 } __attribute__((packed));
 152
 153 struct hvsi_query {
 154         uint8_t  type;
 155         uint8_t  len;
 156         uint16_t seqno;
 157         uint16_t verb;
 158 } __attribute__((packed));
 159
 160 struct hvsi_query_response {
 161         uint8_t  type;
 162         uint8_t  len;
 163         uint16_t seqno;
 164         uint16_t verb;
 165         uint16_t query_seqno;
 166         union {
 167                 uint8_t  version;
 168                 uint32_t mctrl_word;
 169         } u;
 170 } __attribute__((packed));
 171
 172
 173
 174 static inline int is_console(struct hvsi_struct *hp)
 175 {
 176         return hp->flags & HVSI_CONSOLE;
 177 }
 178
 179 static inline int is_open(struct hvsi_struct *hp)
 180 {
 181         /* if we're waiting for an mctrl then we're already open */
 182         return (hp->state == HVSI_OPEN)
 183                         || (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
 184 }
 185
 186 static inline void print_state(struct hvsi_struct *hp)
 187 {
 188 #ifdef DEBUG
 189         static const char *state_names[] = {
 190                 "HVSI_CLOSED",
 191                 "HVSI_WAIT_FOR_VER_RESPONSE",
 192                 "HVSI_WAIT_FOR_VER_QUERY",
 193                 "HVSI_OPEN",
 194                 "HVSI_WAIT_FOR_MCTRL_RESPONSE",
 195                 "HVSI_FSP_DIED",
 196         };
 197         const char *name = state_names[hp->state];
 198
 199         if (hp->state > ARRAY_SIZE(state_names))
 200                 name = "UNKNOWN";
 201
 202         pr_debug("hvsi%i: state = %s\n", hp->index, name);
 203 #endif /* DEBUG */
 204 }
 205
 206 static inline void __set_state(struct hvsi_struct *hp, int state)
 207 {
 208         hp->state = state;
 209         print_state(hp);
 210         wake_up_all(&hp->stateq);
 211 }
 212
 213 static inline void set_state(struct hvsi_struct *hp, int state)
 214 {
 215         unsigned long flags;
 216
 217         spin_lock_irqsave(&hp->lock, flags);
 218         __set_state(hp, state);
 219         spin_unlock_irqrestore(&hp->lock, flags);
 220 }
 221
 222 static inline int len_packet(const uint8_t *packet)
 223 {
 224         return (int)((struct hvsi_header *)packet)->len;
 225 }
 226
 227 static inline int is_header(const uint8_t *packet)
 228 {
 229         struct hvsi_header *header = (struct hvsi_header *)packet;
 230         return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER;
 231 }
 232
 233 static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet)
 234 {
 235         if (hp->inbuf_end < packet + sizeof(struct hvsi_header))
 236                 return 0; /* don't even have the packet header */
 237
 238         if (hp->inbuf_end < (packet + len_packet(packet)))
 239                 return 0; /* don't have the rest of the packet */
 240
 241         return 1;
 242 }
 243
 244 /* shift remaining bytes in packetbuf down */
 245 static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to)
 246 {
 247         int remaining = (int)(hp->inbuf_end - read_to);
 248
 249         pr_debug("%s: %i chars remain\n", __func__, remaining);
 250
 251         if (read_to != hp->inbuf)
 252                 memmove(hp->inbuf, read_to, remaining);
 253
 254         hp->inbuf_end = hp->inbuf + remaining;
 255 }
 256
 257 #ifdef DEBUG
 258 #define dbg_dump_packet(packet) dump_packet(packet)
 259 #define dbg_dump_hex(data, len) dump_hex(data, len)
 260 #else
 261 #define dbg_dump_packet(packet) do { } while (0)
 262 #define dbg_dump_hex(data, len) do { } while (0)
 263 #endif
 264
 265 static void dump_hex(const uint8_t *data, int len)
 266 {
 267         int i;
 268
 269         printk("    ");
 270         for (i=0; i < len; i++)
 271                 printk("%.2x", data[i]);
 272
 273         printk("\n    ");
 274         for (i=0; i < len; i++) {
 275                 if (isprint(data[i]))
 276                         printk("%c", data[i]);
 277                 else
 278                         printk(".");
 279         }
 280         printk("\n");
 281 }
 282
 283 static void dump_packet(uint8_t *packet)
 284 {
 285         struct hvsi_header *header = (struct hvsi_header *)packet;
 286
 287         printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len,
 288                         header->seqno);
 289
 290         dump_hex(packet, header->len);
 291 }
 292
 293 static int hvsi_read(struct hvsi_struct *hp, char *buf, int count)
 294 {
 295         unsigned long got;
 296
 297         got = hvc_get_chars(hp->vtermno, buf, count);
 298
 299         return got;
 300 }
 301
 302 static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet,
 303         struct tty_struct **to_hangup, struct hvsi_struct **to_handshake)
 304 {
 305         struct hvsi_control *header = (struct hvsi_control *)packet;
 306
 307         switch (header->verb) {
 308                 case VSV_MODEM_CTL_UPDATE:
 309                         if ((header->word & HVSI_TSCD) == 0) {
 310                                 /* CD went away; no more connection */
 311                                 pr_debug("hvsi%i: CD dropped\n", hp->index);
 312                                 hp->mctrl &= TIOCM_CD;
 313                                 /* If userland hasn't done an open(2) yet, hp->tty is NULL. */
 314                                 if (hp->tty && !(hp->tty->flags & CLOCAL))
 315                                         *to_hangup = hp->tty;
 316                         }
 317                         break;
 318                 case VSV_CLOSE_PROTOCOL:
 319                         pr_debug("hvsi%i: service processor came back\n", hp->index);
 320                         if (hp->state != HVSI_CLOSED) {
 321                                 *to_handshake = hp;
 322                         }
 323                         break;
 324                 default:
 325                         printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ",
 326                                 hp->index);
 327                         dump_packet(packet);
 328                         break;
 329         }
 330 }
 331
 332 static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet)
 333 {
 334         struct hvsi_query_response *resp = (struct hvsi_query_response *)packet;
 335
 336         switch (hp->state) {
 337                 case HVSI_WAIT_FOR_VER_RESPONSE:
 338                         __set_state(hp, HVSI_WAIT_FOR_VER_QUERY);
 339                         break;
 340                 case HVSI_WAIT_FOR_MCTRL_RESPONSE:
 341                         hp->mctrl = 0;
 342                         if (resp->u.mctrl_word & HVSI_TSDTR)
 343                                 hp->mctrl |= TIOCM_DTR;
 344                         if (resp->u.mctrl_word & HVSI_TSCD)
 345                                 hp->mctrl |= TIOCM_CD;
 346                         __set_state(hp, HVSI_OPEN);
 347                         break;
 348                 default:
 349                         printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index);
 350                         dump_packet(packet);
 351                         break;
 352         }
 353 }
 354
 355 /* respond to service processor's version query */
 356 static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno)
 357 {
 358         struct hvsi_query_response packet __ALIGNED__;
 359         int wrote;
 360
 361         packet.type = VS_QUERY_RESPONSE_PACKET_HEADER;
 362         packet.len = sizeof(struct hvsi_query_response);
 363         packet.seqno = atomic_inc_return(&hp->seqno);
 364         packet.verb = VSV_SEND_VERSION_NUMBER;
 365         packet.u.version = HVSI_VERSION;
 366         packet.query_seqno = query_seqno+1;
 367
 368         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
 369         dbg_dump_hex((uint8_t*)&packet, packet.len);
 370
 371         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 372         if (wrote != packet.len) {
 373                 printk(KERN_ERR "hvsi%i: couldn't send query response!\n",
 374                         hp->index);
 375                 return -EIO;
 376         }
 377
 378         return 0;
 379 }
 380
 381 static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet)
 382 {
 383         struct hvsi_query *query = (struct hvsi_query *)packet;
 384
 385         switch (hp->state) {
 386                 case HVSI_WAIT_FOR_VER_QUERY:
 387                         hvsi_version_respond(hp, query->seqno);
 388                         __set_state(hp, HVSI_OPEN);
 389                         break;
 390                 default:
 391                         printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index);
 392                         dump_packet(packet);
 393                         break;
 394         }
 395 }
 396
 397 static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len)
 398 {
 399         int i;
 400
 401         for (i=0; i < len; i++) {
 402                 char c = buf[i];
 403 #ifdef CONFIG_MAGIC_SYSRQ
 404                 if (c == '\0') {
 405                         hp->sysrq = 1;
 406                         continue;
 407                 } else if (hp->sysrq) {
 408                         handle_sysrq(c, hp->tty);
 409                         hp->sysrq = 0;
 410                         continue;
 411                 }
 412 #endif /* CONFIG_MAGIC_SYSRQ */
 413                 tty_insert_flip_char(hp->tty, c, 0);
 414         }
 415 }
 416
 417 /*
 418  * We could get 252 bytes of data at once here. But the tty layer only
 419  * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow
 420  * it. Accordingly we won't send more than 128 bytes at a time to the flip
 421  * buffer, which will give the tty buffer a chance to throttle us. Should the
 422  * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be
 423  * revisited.
 424  */
 425 #define TTY_THRESHOLD_THROTTLE 128
 426 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp,
 427                 const uint8_t *packet)
 428 {
 429         const struct hvsi_header *header = (const struct hvsi_header *)packet;
 430         const uint8_t *data = packet + sizeof(struct hvsi_header);
 431         int datalen = header->len - sizeof(struct hvsi_header);
 432         int overflow = datalen - TTY_THRESHOLD_THROTTLE;
 433
 434         pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data);
 435
 436         if (datalen == 0)
 437                 return NULL;
 438
 439         if (overflow > 0) {
 440                 pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__);
 441                 datalen = TTY_THRESHOLD_THROTTLE;
 442         }
 443
 444         hvsi_insert_chars(hp, data, datalen);
 445
 446         if (overflow > 0) {
 447                 /*
 448                  * we still have more data to deliver, so we need to save off the
 449                  * overflow and send it later
 450                  */
 451                 pr_debug("%s: deferring overflow\n", __func__);
 452                 memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow);
 453                 hp->n_throttle = overflow;
 454         }
 455
 456         return hp->tty;
 457 }
 458
 459 /*
 460  * Returns true/false indicating data successfully read from hypervisor.
 461  * Used both to get packets for tty connections and to advance the state
 462  * machine during console handshaking (in which case tty = NULL and we ignore
 463  * incoming data).
 464  */
 465 static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip,
 466                 struct tty_struct **hangup, struct hvsi_struct **handshake)
 467 {
 468         uint8_t *packet = hp->inbuf;
 469         int chunklen;
 470
 471         *flip = NULL;
 472         *hangup = NULL;
 473         *handshake = NULL;
 474
 475         chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ);
 476         if (chunklen == 0) {
 477                 pr_debug("%s: 0-length read\n", __func__);
 478                 return 0;
 479         }
 480
 481         pr_debug("%s: got %i bytes\n", __func__, chunklen);
 482         dbg_dump_hex(hp->inbuf_end, chunklen);
 483
 484         hp->inbuf_end += chunklen;
 485
 486         /* handle all completed packets */
 487         while ((packet < hp->inbuf_end) && got_packet(hp, packet)) {
 488                 struct hvsi_header *header = (struct hvsi_header *)packet;
 489
 490                 if (!is_header(packet)) {
 491                         printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index);
 492                         /* skip bytes until we find a header or run out of data */
 493                         while ((packet < hp->inbuf_end) && (!is_header(packet)))
 494                                 packet++;
 495                         continue;
 496                 }
 497
 498                 pr_debug("%s: handling %i-byte packet\n", __func__,
 499                                 len_packet(packet));
 500                 dbg_dump_packet(packet);
 501
 502                 switch (header->type) {
 503                         case VS_DATA_PACKET_HEADER:
 504                                 if (!is_open(hp))
 505                                         break;
 506                                 if (hp->tty == NULL)
 507                                         break; /* no tty buffer to put data in */
 508                                 *flip = hvsi_recv_data(hp, packet);
 509                                 break;
 510                         case VS_CONTROL_PACKET_HEADER:
 511                                 hvsi_recv_control(hp, packet, hangup, handshake);
 512                                 break;
 513                         case VS_QUERY_RESPONSE_PACKET_HEADER:
 514                                 hvsi_recv_response(hp, packet);
 515                                 break;
 516                         case VS_QUERY_PACKET_HEADER:
 517                                 hvsi_recv_query(hp, packet);
 518                                 break;
 519                         default:
 520                                 printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n",
 521                                                 hp->index, header->type);
 522                                 dump_packet(packet);
 523                                 break;
 524                 }
 525
 526                 packet += len_packet(packet);
 527
 528                 if (*hangup || *handshake) {
 529                         pr_debug("%s: hangup or handshake\n", __func__);
 530                         /*
 531                          * we need to send the hangup now before receiving any more data.
 532                          * If we get "data, hangup, data", we can't deliver the second
 533                          * data before the hangup.
 534                          */
 535                         break;
 536                 }
 537         }
 538
 539         compact_inbuf(hp, packet);
 540
 541         return 1;
 542 }
 543
 544 static void hvsi_send_overflow(struct hvsi_struct *hp)
 545 {
 546         pr_debug("%s: delivering %i bytes overflow\n", __func__,
 547                         hp->n_throttle);
 548
 549         hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle);
 550         hp->n_throttle = 0;
 551 }
 552
 553 /*
 554  * must get all pending data because we only get an irq on empty->non-empty
 555  * transition
 556  */
 557 static irqreturn_t hvsi_interrupt(int irq, void *arg)
 558 {
 559         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
 560         struct tty_struct *flip;
 561         struct tty_struct *hangup;
 562         struct hvsi_struct *handshake;
 563         unsigned long flags;
 564         int again = 1;
 565
 566         pr_debug("%s\n", __func__);
 567
 568         while (again) {
 569                 spin_lock_irqsave(&hp->lock, flags);
 570                 again = hvsi_load_chunk(hp, &flip, &hangup, &handshake);
 571                 spin_unlock_irqrestore(&hp->lock, flags);
 572
 573                 /*
 574                  * we have to call tty_flip_buffer_push() and tty_hangup() outside our
 575                  * spinlock. But we also have to keep going until we've read all the
 576                  * available data.
 577                  */
 578
 579                 if (flip) {
 580                         /* there was data put in the tty flip buffer */
 581                         tty_flip_buffer_push(flip);
 582                         flip = NULL;
 583                 }
 584
 585                 if (hangup) {
 586                         tty_hangup(hangup);
 587                 }
 588
 589                 if (handshake) {
 590                         pr_debug("hvsi%i: attempting re-handshake\n", handshake->index);
 591                         schedule_work(&handshake->handshaker);
 592                 }
 593         }
 594
 595         spin_lock_irqsave(&hp->lock, flags);
 596         if (hp->tty && hp->n_throttle
 597                         && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
 598                 /* we weren't hung up and we weren't throttled, so we can deliver the
 599                  * rest now */
 600                 flip = hp->tty;
 601                 hvsi_send_overflow(hp);
 602         }
 603         spin_unlock_irqrestore(&hp->lock, flags);
 604
 605         if (flip) {
 606                 tty_flip_buffer_push(flip);
 607         }
 608
 609         return IRQ_HANDLED;
 610 }
 611
 612 /* for boot console, before the irq handler is running */
 613 static int __init poll_for_state(struct hvsi_struct *hp, int state)
 614 {
 615         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 616
 617         for (;;) {
 618                 hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */
 619
 620                 if (hp->state == state)
 621                         return 0;
 622
 623                 mdelay(5);
 624                 if (time_after(jiffies, end_jiffies))
 625                         return -EIO;
 626         }
 627 }
 628
 629 /* wait for irq handler to change our state */
 630 static int wait_for_state(struct hvsi_struct *hp, int state)
 631 {
 632         int ret = 0;
 633
 634         if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT))
 635                 ret = -EIO;
 636
 637         return ret;
 638 }
 639
 640 static int hvsi_query(struct hvsi_struct *hp, uint16_t verb)
 641 {
 642         struct hvsi_query packet __ALIGNED__;
 643         int wrote;
 644
 645         packet.type = VS_QUERY_PACKET_HEADER;
 646         packet.len = sizeof(struct hvsi_query);
 647         packet.seqno = atomic_inc_return(&hp->seqno);
 648         packet.verb = verb;
 649
 650         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
 651         dbg_dump_hex((uint8_t*)&packet, packet.len);
 652
 653         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 654         if (wrote != packet.len) {
 655                 printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index,
 656                         wrote);
 657                 return -EIO;
 658         }
 659
 660         return 0;
 661 }
 662
 663 static int hvsi_get_mctrl(struct hvsi_struct *hp)
 664 {
 665         int ret;
 666
 667         set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE);
 668         hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS);
 669
 670         ret = hvsi_wait(hp, HVSI_OPEN);
 671         if (ret < 0) {
 672                 printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index);
 673                 set_state(hp, HVSI_OPEN);
 674                 return ret;
 675         }
 676
 677         pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl);
 678
 679         return 0;
 680 }
 681
 682 /* note that we can only set DTR */
 683 static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl)
 684 {
 685         struct hvsi_control packet __ALIGNED__;
 686         int wrote;
 687
 688         packet.type = VS_CONTROL_PACKET_HEADER,
 689         packet.seqno = atomic_inc_return(&hp->seqno);
 690         packet.len = sizeof(struct hvsi_control);
 691         packet.verb = VSV_SET_MODEM_CTL;
 692         packet.mask = HVSI_TSDTR;
 693
 694         if (mctrl & TIOCM_DTR)
 695                 packet.word = HVSI_TSDTR;
 696
 697         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
 698         dbg_dump_hex((uint8_t*)&packet, packet.len);
 699
 700         wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 701         if (wrote != packet.len) {
 702                 printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index);
 703                 return -EIO;
 704         }
 705
 706         return 0;
 707 }
 708
 709 static void hvsi_drain_input(struct hvsi_struct *hp)
 710 {
 711         uint8_t buf[HVSI_MAX_READ] __ALIGNED__;
 712         unsigned long end_jiffies = jiffies + HVSI_TIMEOUT;
 713
 714         while (time_before(end_jiffies, jiffies))
 715                 if (0 == hvsi_read(hp, buf, HVSI_MAX_READ))
 716                         break;
 717 }
 718
 719 static int hvsi_handshake(struct hvsi_struct *hp)
 720 {
 721         int ret;
 722
 723         /*
 724          * We could have a CLOSE or other data waiting for us before we even try
 725          * to open; try to throw it all away so we don't get confused. (CLOSE
 726          * is the first message sent up the pipe when the FSP comes online. We
 727          * need to distinguish between "it came up a while ago and we're the first
 728          * user" and "it was just reset before it saw our handshake packet".)
 729          */
 730         hvsi_drain_input(hp);
 731
 732         set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE);
 733         ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER);
 734         if (ret < 0) {
 735                 printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index);
 736                 return ret;
 737         }
 738
 739         ret = hvsi_wait(hp, HVSI_OPEN);
 740         if (ret < 0)
 741                 return ret;
 742
 743         return 0;
 744 }
 745
 746 static void hvsi_handshaker(struct work_struct *work)
 747 {
 748         struct hvsi_struct *hp =
 749                 container_of(work, struct hvsi_struct, handshaker);
 750
 751         if (hvsi_handshake(hp) >= 0)
 752                 return;
 753
 754         printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index);
 755         if (is_console(hp)) {
 756                 /*
 757                  * ttys will re-attempt the handshake via hvsi_open, but
 758                  * the console will not.
 759                  */
 760                 printk(KERN_ERR "hvsi%i: lost console!\n", hp->index);
 761         }
 762 }
 763
 764 static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count)
 765 {
 766         struct hvsi_data packet __ALIGNED__;
 767         int ret;
 768
 769         BUG_ON(count > HVSI_MAX_OUTGOING_DATA);
 770
 771         packet.type = VS_DATA_PACKET_HEADER;
 772         packet.seqno = atomic_inc_return(&hp->seqno);
 773         packet.len = count + sizeof(struct hvsi_header);
 774         memcpy(&packet.data, buf, count);
 775
 776         ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 777         if (ret == packet.len) {
 778                 /* return the number of chars written, not the packet length */
 779                 return count;
 780         }
 781         return ret; /* return any errors */
 782 }
 783
 784 static void hvsi_close_protocol(struct hvsi_struct *hp)
 785 {
 786         struct hvsi_control packet __ALIGNED__;
 787
 788         packet.type = VS_CONTROL_PACKET_HEADER;
 789         packet.seqno = atomic_inc_return(&hp->seqno);
 790         packet.len = 6;
 791         packet.verb = VSV_CLOSE_PROTOCOL;
 792
 793         pr_debug("%s: sending %i bytes\n", __func__, packet.len);
 794         dbg_dump_hex((uint8_t*)&packet, packet.len);
 795
 796         hvc_put_chars(hp->vtermno, (char *)&packet, packet.len);
 797 }
 798
 799 static int hvsi_open(struct tty_struct *tty, struct file *filp)
 800 {
 801         struct hvsi_struct *hp;
 802         unsigned long flags;
 803         int line = tty->index;
 804         int ret;
 805
 806         pr_debug("%s\n", __func__);
 807
 808         if (line < 0 || line >= hvsi_count)
 809                 return -ENODEV;
 810         hp = &hvsi_ports[line];
 811
 812         tty->driver_data = hp;
 813
 814         mb();
 815         if (hp->state == HVSI_FSP_DIED)
 816                 return -EIO;
 817
 818         spin_lock_irqsave(&hp->lock, flags);
 819         hp->tty = tty;
 820         hp->count++;
 821         atomic_set(&hp->seqno, 0);
 822         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
 823         spin_unlock_irqrestore(&hp->lock, flags);
 824
 825         if (is_console(hp))
 826                 return 0; /* this has already been handshaked as the console */
 827
 828         ret = hvsi_handshake(hp);
 829         if (ret < 0) {
 830                 printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name);
 831                 return ret;
 832         }
 833
 834         ret = hvsi_get_mctrl(hp);
 835         if (ret < 0) {
 836                 printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name);
 837                 return ret;
 838         }
 839
 840         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
 841         if (ret < 0) {
 842                 printk(KERN_ERR "%s: couldn't set DTR\n", tty->name);
 843                 return ret;
 844         }
 845
 846         return 0;
 847 }
 848
 849 /* wait for hvsi_write_worker to empty hp->outbuf */
 850 static void hvsi_flush_output(struct hvsi_struct *hp)
 851 {
 852         wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT);
 853
 854         /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */
 855         cancel_delayed_work(&hp->writer);
 856         flush_scheduled_work();
 857
 858         /*
 859          * it's also possible that our timeout expired and hvsi_write_worker
 860          * didn't manage to push outbuf. poof.
 861          */
 862         hp->n_outbuf = 0;
 863 }
 864
 865 static void hvsi_close(struct tty_struct *tty, struct file *filp)
 866 {
 867         struct hvsi_struct *hp = tty->driver_data;
 868         unsigned long flags;
 869
 870         pr_debug("%s\n", __func__);
 871
 872         if (tty_hung_up_p(filp))
 873                 return;
 874
 875         spin_lock_irqsave(&hp->lock, flags);
 876
 877         if (--hp->count == 0) {
 878                 hp->tty = NULL;
 879                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
 880
 881                 /* only close down connection if it is not the console */
 882                 if (!is_console(hp)) {
 883                         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */
 884                         __set_state(hp, HVSI_CLOSED);
 885                         /*
 886                          * any data delivered to the tty layer after this will be
 887                          * discarded (except for XON/XOFF)
 888                          */
 889                         tty->closing = 1;
 890
 891                         spin_unlock_irqrestore(&hp->lock, flags);
 892
 893                         /* let any existing irq handlers finish. no more will start. */
 894                         synchronize_irq(hp->virq);
 895
 896                         /* hvsi_write_worker will re-schedule until outbuf is empty. */
 897                         hvsi_flush_output(hp);
 898
 899                         /* tell FSP to stop sending data */
 900                         hvsi_close_protocol(hp);
 901
 902                         /*
 903                          * drain anything FSP is still in the middle of sending, and let
 904                          * hvsi_handshake drain the rest on the next open.
 905                          */
 906                         hvsi_drain_input(hp);
 907
 908                         spin_lock_irqsave(&hp->lock, flags);
 909                 }
 910         } else if (hp->count < 0)
 911                 printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n",
 912                        hp - hvsi_ports, hp->count);
 913
 914         spin_unlock_irqrestore(&hp->lock, flags);
 915 }
 916
 917 static void hvsi_hangup(struct tty_struct *tty)
 918 {
 919         struct hvsi_struct *hp = tty->driver_data;
 920         unsigned long flags;
 921
 922         pr_debug("%s\n", __func__);
 923
 924         spin_lock_irqsave(&hp->lock, flags);
 925
 926         hp->count = 0;
 927         hp->n_outbuf = 0;
 928         hp->tty = NULL;
 929
 930         spin_unlock_irqrestore(&hp->lock, flags);
 931 }
 932
 933 /* called with hp->lock held */
 934 static void hvsi_push(struct hvsi_struct *hp)
 935 {
 936         int n;
 937
 938         if (hp->n_outbuf <= 0)
 939                 return;
 940
 941         n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf);
 942         if (n > 0) {
 943                 /* success */
 944                 pr_debug("%s: wrote %i chars\n", __func__, n);
 945                 hp->n_outbuf = 0;
 946         } else if (n == -EIO) {
 947                 __set_state(hp, HVSI_FSP_DIED);
 948                 printk(KERN_ERR "hvsi%i: service processor died\n", hp->index);
 949         }
 950 }
 951
 952 /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */
 953 static void hvsi_write_worker(struct work_struct *work)
 954 {
 955         struct hvsi_struct *hp =
 956                 container_of(work, struct hvsi_struct, writer.work);
 957         unsigned long flags;
 958 #ifdef DEBUG
 959         static long start_j = 0;
 960
 961         if (start_j == 0)
 962                 start_j = jiffies;
 963 #endif /* DEBUG */
 964
 965         spin_lock_irqsave(&hp->lock, flags);
 966
 967         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
 968
 969         if (!is_open(hp)) {
 970                 /*
 971                  * We could have a non-open connection if the service processor died
 972                  * while we were busily scheduling ourselves. In that case, it could
 973                  * be minutes before the service processor comes back, so only try
 974                  * again once a second.
 975                  */
 976                 schedule_delayed_work(&hp->writer, HZ);
 977                 goto out;
 978         }
 979
 980         hvsi_push(hp);
 981         if (hp->n_outbuf > 0)
 982                 schedule_delayed_work(&hp->writer, 10);
 983         else {
 984 #ifdef DEBUG
 985                 pr_debug("%s: outbuf emptied after %li jiffies\n", __func__,
 986                                 jiffies - start_j);
 987                 start_j = 0;
 988 #endif /* DEBUG */
 989                 wake_up_all(&hp->emptyq);
 990                 tty_wakeup(hp->tty);
 991         }
 992
 993 out:
 994         spin_unlock_irqrestore(&hp->lock, flags);
 995 }
 996
 997 static int hvsi_write_room(struct tty_struct *tty)
 998 {
 999         struct hvsi_struct *hp = tty->driver_data;
1000
1001         return N_OUTBUF - hp->n_outbuf;
1002 }
1003
1004 static int hvsi_chars_in_buffer(struct tty_struct *tty)
1005 {
1006         struct hvsi_struct *hp = tty->driver_data;
1007
1008         return hp->n_outbuf;
1009 }
1010
1011 static int hvsi_write(struct tty_struct *tty,
1012                      const unsigned char *buf, int count)
1013 {
1014         struct hvsi_struct *hp = tty->driver_data;
1015         const char *source = buf;
1016         unsigned long flags;
1017         int total = 0;
1018         int origcount = count;
1019
1020         spin_lock_irqsave(&hp->lock, flags);
1021
1022         pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf);
1023
1024         if (!is_open(hp)) {
1025                 /* we're either closing or not yet open; don't accept data */
1026                 pr_debug("%s: not open\n", __func__);
1027                 goto out;
1028         }
1029
1030         /*
1031          * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf
1032          * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls
1033          * will see there is no room in outbuf and return.
1034          */
1035         while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) {
1036                 int chunksize = min(count, hvsi_write_room(hp->tty));
1037
1038                 BUG_ON(hp->n_outbuf < 0);
1039                 memcpy(hp->outbuf + hp->n_outbuf, source, chunksize);
1040                 hp->n_outbuf += chunksize;
1041
1042                 total += chunksize;
1043                 source += chunksize;
1044                 count -= chunksize;
1045                 hvsi_push(hp);
1046         }
1047
1048         if (hp->n_outbuf > 0) {
1049                 /*
1050                  * we weren't able to write it all to the hypervisor.
1051                  * schedule another push attempt.
1052                  */
1053                 schedule_delayed_work(&hp->writer, 10);
1054         }
1055
1056 out:
1057         spin_unlock_irqrestore(&hp->lock, flags);
1058
1059         if (total != origcount)
1060                 pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount,
1061                         total);
1062
1063         return total;
1064 }
1065
1066 /*
1067  * I have never seen throttle or unthrottle called, so this little throttle
1068  * buffering scheme may or may not work.
1069  */
1070 static void hvsi_throttle(struct tty_struct *tty)
1071 {
1072         struct hvsi_struct *hp = tty->driver_data;
1073
1074         pr_debug("%s\n", __func__);
1075
1076         h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE);
1077 }
1078
1079 static void hvsi_unthrottle(struct tty_struct *tty)
1080 {
1081         struct hvsi_struct *hp = tty->driver_data;
1082         unsigned long flags;
1083         int shouldflip = 0;
1084
1085         pr_debug("%s\n", __func__);
1086
1087         spin_lock_irqsave(&hp->lock, flags);
1088         if (hp->n_throttle) {
1089                 hvsi_send_overflow(hp);
1090                 shouldflip = 1;
1091         }
1092         spin_unlock_irqrestore(&hp->lock, flags);
1093
1094         if (shouldflip)
1095                 tty_flip_buffer_push(hp->tty);
1096
1097         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
1098 }
1099
1100 static int hvsi_tiocmget(struct tty_struct *tty, struct file *file)
1101 {
1102         struct hvsi_struct *hp = tty->driver_data;
1103
1104         hvsi_get_mctrl(hp);
1105         return hp->mctrl;
1106 }
1107
1108 static int hvsi_tiocmset(struct tty_struct *tty, struct file *file,
1109                 unsigned int set, unsigned int clear)
1110 {
1111         struct hvsi_struct *hp = tty->driver_data;
1112         unsigned long flags;
1113         uint16_t new_mctrl;
1114
1115         /* we can only alter DTR */
1116         clear &= TIOCM_DTR;
1117         set &= TIOCM_DTR;
1118
1119         spin_lock_irqsave(&hp->lock, flags);
1120
1121         new_mctrl = (hp->mctrl & ~clear) | set;
1122
1123         if (hp->mctrl != new_mctrl) {
1124                 hvsi_set_mctrl(hp, new_mctrl);
1125                 hp->mctrl = new_mctrl;
1126         }
1127         spin_unlock_irqrestore(&hp->lock, flags);
1128
1129         return 0;
1130 }
1131
1132
1133 static const struct tty_operations hvsi_ops = {
1134         .open = hvsi_open,
1135         .close = hvsi_close,
1136         .write = hvsi_write,
1137         .hangup = hvsi_hangup,
1138         .write_room = hvsi_write_room,
1139         .chars_in_buffer = hvsi_chars_in_buffer,
1140         .throttle = hvsi_throttle,
1141         .unthrottle = hvsi_unthrottle,
1142         .tiocmget = hvsi_tiocmget,
1143         .tiocmset = hvsi_tiocmset,
1144 };
1145
1146 static int __init hvsi_init(void)
1147 {
1148         int i;
1149
1150         hvsi_driver = alloc_tty_driver(hvsi_count);
1151         if (!hvsi_driver)
1152                 return -ENOMEM;
1153
1154         hvsi_driver->owner = THIS_MODULE;
1155         hvsi_driver->driver_name = "hvsi";
1156         hvsi_driver->name = "hvsi";
1157         hvsi_driver->major = HVSI_MAJOR;
1158         hvsi_driver->minor_start = HVSI_MINOR;
1159         hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM;
1160         hvsi_driver->init_termios = tty_std_termios;
1161         hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL;
1162         hvsi_driver->init_termios.c_ispeed = 9600;
1163         hvsi_driver->init_termios.c_ospeed = 9600;
1164         hvsi_driver->flags = TTY_DRIVER_REAL_RAW;
1165         tty_set_operations(hvsi_driver, &hvsi_ops);
1166
1167         for (i=0; i < hvsi_count; i++) {
1168                 struct hvsi_struct *hp = &hvsi_ports[i];
1169                 int ret = 1;
1170
1171                 ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp);
1172                 if (ret)
1173                         printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n",
1174                                 hp->virq, ret);
1175         }
1176         hvsi_wait = wait_for_state; /* irqs active now */
1177
1178         if (tty_register_driver(hvsi_driver))
1179                 panic("Couldn't register hvsi console driver\n");
1180
1181         printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count);
1182
1183         return 0;
1184 }
1185 device_initcall(hvsi_init);
1186
1187 /***** console (not tty) code: *****/
1188
1189 static void hvsi_console_print(struct console *console, const char *buf,
1190                 unsigned int count)
1191 {
1192         struct hvsi_struct *hp = &hvsi_ports[console->index];
1193         char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__;
1194         unsigned int i = 0, n = 0;
1195         int ret, donecr = 0;
1196
1197         mb();
1198         if (!is_open(hp))
1199                 return;
1200
1201         /*
1202          * ugh, we have to translate LF -> CRLF ourselves, in place.
1203          * copied from hvc_console.c:
1204          */
1205         while (count > 0 || i > 0) {
1206                 if (count > 0 && i < sizeof(c)) {
1207                         if (buf[n] == '\n' && !donecr) {
1208                                 c[i++] = '\r';
1209                                 donecr = 1;
1210                         } else {
1211                                 c[i++] = buf[n++];
1212                                 donecr = 0;
1213                                 --count;
1214                         }
1215                 } else {
1216                         ret = hvsi_put_chars(hp, c, i);
1217                         if (ret < 0)
1218                                 i = 0;
1219                         i -= ret;
1220                 }
1221         }
1222 }
1223
1224 static struct tty_driver *hvsi_console_device(struct console *console,
1225         int *index)
1226 {
1227         *index = console->index;
1228         return hvsi_driver;
1229 }
1230
1231 static int __init hvsi_console_setup(struct console *console, char *options)
1232 {
1233         struct hvsi_struct *hp = &hvsi_ports[console->index];
1234         int ret;
1235
1236         if (console->index < 0 || console->index >= hvsi_count)
1237                 return -1;
1238
1239         /* give the FSP a chance to change the baud rate when we re-open */
1240         hvsi_close_protocol(hp);
1241
1242         ret = hvsi_handshake(hp);
1243         if (ret < 0)
1244                 return ret;
1245
1246         ret = hvsi_get_mctrl(hp);
1247         if (ret < 0)
1248                 return ret;
1249
1250         ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR);
1251         if (ret < 0)
1252                 return ret;
1253
1254         hp->flags |= HVSI_CONSOLE;
1255
1256         return 0;
1257 }
1258
1259 static struct console hvsi_con_driver = {
1260         .name           = "hvsi",
1261         .write          = hvsi_console_print,
1262         .device         = hvsi_console_device,
1263         .setup          = hvsi_console_setup,
1264         .flags          = CON_PRINTBUFFER,
1265         .index          = -1,
1266 };
1267
1268 static int __init hvsi_console_init(void)
1269 {
1270         struct device_node *vty;
1271
1272         hvsi_wait = poll_for_state; /* no irqs yet; must poll */
1273
1274         /* search device tree for vty nodes */
1275         for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol");
1276                         vty != NULL;
1277                         vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) {
1278                 struct hvsi_struct *hp;
1279                 const uint32_t *vtermno, *irq;
1280
1281                 vtermno = of_get_property(vty, "reg", NULL);
1282                 irq = of_get_property(vty, "interrupts", NULL);
1283                 if (!vtermno || !irq)
1284                         continue;
1285
1286                 if (hvsi_count >= MAX_NR_HVSI_CONSOLES) {
1287                         of_node_put(vty);
1288                         break;
1289                 }
1290
1291                 hp = &hvsi_ports[hvsi_count];
1292                 INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker);
1293                 INIT_WORK(&hp->handshaker, hvsi_handshaker);
1294                 init_waitqueue_head(&hp->emptyq);
1295                 init_waitqueue_head(&hp->stateq);
1296                 spin_lock_init(&hp->lock);
1297                 hp->index = hvsi_count;
1298                 hp->inbuf_end = hp->inbuf;
1299                 hp->state = HVSI_CLOSED;
1300                 hp->vtermno = *vtermno;
1301                 hp->virq = irq_create_mapping(NULL, irq[0]);
1302                 if (hp->virq == NO_IRQ) {
1303                         printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n",
1304                                 __func__, irq[0]);
1305                         continue;
1306                 }
1307
1308                 hvsi_count++;
1309         }
1310
1311         if (hvsi_count)
1312                 register_console(&hvsi_con_driver);
1313         return 0;
1314 }
1315 console_initcall(hvsi_console_init);