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