drivers/char/viocons.c

   1 /* -*- linux-c -*-
   2  *
   3  *  drivers/char/viocons.c
   4  *
   5  *  iSeries Virtual Terminal
   6  *
   7  *  Authors: Dave Boutcher <boutcher@us.ibm.com>
   8  *           Ryan Arnold <ryanarn@us.ibm.com>
   9  *           Colin Devilbiss <devilbis@us.ibm.com>
  10  *           Stephen Rothwell <sfr@au1.ibm.com>
  11  *
  12  * (C) Copyright 2000, 2001, 2002, 2003, 2004 IBM Corporation
  13  *
  14  * This program is free software;  you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) anyu later version.
  18  *
  19  * This program is distributed in the hope that it will be useful, but
  20  * WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  22  * General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  27  */
  28 #include <linux/kernel.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/errno.h>
  31 #include <linux/vmalloc.h>
  32 #include <linux/mm.h>
  33 #include <linux/console.h>
  34 #include <linux/module.h>
  35 #include <asm/uaccess.h>
  36 #include <linux/init.h>
  37 #include <linux/wait.h>
  38 #include <linux/spinlock.h>
  39 #include <asm/ioctls.h>
  40 #include <linux/kd.h>
  41 #include <linux/tty.h>
  42 #include <linux/tty_flip.h>
  43 #include <linux/sysrq.h>
  44
  45 #include <asm/iseries/vio.h>
  46
  47 #include <asm/iseries/hv_lp_event.h>
  48 #include <asm/iseries/hv_call_event.h>
  49 #include <asm/iseries/hv_lp_config.h>
  50 #include <asm/iseries/hv_call.h>
  51
  52 #ifdef CONFIG_VT
  53 #error You must turn off CONFIG_VT to use CONFIG_VIOCONS
  54 #endif
  55
  56 #define VIOTTY_MAGIC (0x0DCB)
  57 #define VTTY_PORTS 10
  58
  59 #define VIOCONS_KERN_WARN       KERN_WARNING "viocons: "
  60 #define VIOCONS_KERN_INFO       KERN_INFO "viocons: "
  61
  62 static DEFINE_SPINLOCK(consolelock);
  63 static DEFINE_SPINLOCK(consoleloglock);
  64
  65 #ifdef CONFIG_MAGIC_SYSRQ
  66 static int vio_sysrq_pressed;
  67 extern int sysrq_enabled;
  68 #endif
  69
  70 /*
  71  * The structure of the events that flow between us and OS/400.  You can't
  72  * mess with this unless the OS/400 side changes too
  73  */
  74 struct viocharlpevent {
  75         struct HvLpEvent event;
  76         u32 reserved;
  77         u16 version;
  78         u16 subtype_result_code;
  79         u8 virtual_device;
  80         u8 len;
  81         u8 data[VIOCHAR_MAX_DATA];
  82 };
  83
  84 #define VIOCHAR_WINDOW          10
  85 #define VIOCHAR_HIGHWATERMARK   3
  86
  87 enum viocharsubtype {
  88         viocharopen = 0x0001,
  89         viocharclose = 0x0002,
  90         viochardata = 0x0003,
  91         viocharack = 0x0004,
  92         viocharconfig = 0x0005
  93 };
  94
  95 enum viochar_rc {
  96         viochar_rc_ebusy = 1
  97 };
  98
  99 #define VIOCHAR_NUM_BUF         16
 100
 101 /*
 102  * Our port information.  We store a pointer to one entry in the
 103  * tty_driver_data
 104  */
 105 static struct port_info {
 106         int magic;
 107         struct tty_struct *tty;
 108         HvLpIndex lp;
 109         u8 vcons;
 110         u64 seq;        /* sequence number of last HV send */
 111         u64 ack;        /* last ack from HV */
 112 /*
 113  * When we get writes faster than we can send it to the partition,
 114  * buffer the data here. Note that used is a bit map of used buffers.
 115  * It had better have enough bits to hold VIOCHAR_NUM_BUF the bitops assume
 116  * it is a multiple of unsigned long
 117  */
 118         unsigned long used;
 119         u8 *buffer[VIOCHAR_NUM_BUF];
 120         int bufferBytes[VIOCHAR_NUM_BUF];
 121         int curbuf;
 122         int bufferOverflow;
 123         int overflowMessage;
 124 } port_info[VTTY_PORTS];
 125
 126 #define viochar_is_console(pi)  ((pi) == &port_info[0])
 127 #define viochar_port(pi)        ((pi) - &port_info[0])
 128
 129 static void initDataEvent(struct viocharlpevent *viochar, HvLpIndex lp);
 130
 131 static struct tty_driver *viotty_driver;
 132
 133 static void hvlog(char *fmt, ...)
 134 {
 135         int i;
 136         unsigned long flags;
 137         va_list args;
 138         static char buf[256];
 139
 140         spin_lock_irqsave(&consoleloglock, flags);
 141         va_start(args, fmt);
 142         i = vscnprintf(buf, sizeof(buf) - 1, fmt, args);
 143         va_end(args);
 144         buf[i++] = '\r';
 145         HvCall_writeLogBuffer(buf, i);
 146         spin_unlock_irqrestore(&consoleloglock, flags);
 147 }
 148
 149 static void hvlogOutput(const char *buf, int count)
 150 {
 151         unsigned long flags;
 152         int begin;
 153         int index;
 154         static const char cr = '\r';
 155
 156         begin = 0;
 157         spin_lock_irqsave(&consoleloglock, flags);
 158         for (index = 0; index < count; index++) {
 159                 if (buf[index] == '\n') {
 160                         /*
 161                          * Start right after the last '\n' or at the zeroth
 162                          * array position and output the number of characters
 163                          * including the newline.
 164                          */
 165                         HvCall_writeLogBuffer(&buf[begin], index - begin + 1);
 166                         begin = index + 1;
 167                         HvCall_writeLogBuffer(&cr, 1);
 168                 }
 169         }
 170         if ((index - begin) > 0)
 171                 HvCall_writeLogBuffer(&buf[begin], index - begin);
 172         spin_unlock_irqrestore(&consoleloglock, flags);
 173 }
 174
 175 /*
 176  * Make sure we're pointing to a valid port_info structure.  Shamelessly
 177  * plagerized from serial.c
 178  */
 179 static inline int viotty_paranoia_check(struct port_info *pi,
 180                                         char *name, const char *routine)
 181 {
 182         static const char *bad_pi_addr = VIOCONS_KERN_WARN
 183                 "warning: bad address for port_info struct (%s) in %s\n";
 184         static const char *badmagic = VIOCONS_KERN_WARN
 185                 "warning: bad magic number for port_info struct (%s) in %s\n";
 186
 187         if ((pi < &port_info[0]) || (viochar_port(pi) > VTTY_PORTS)) {
 188                 printk(bad_pi_addr, name, routine);
 189                 return 1;
 190         }
 191         if (pi->magic != VIOTTY_MAGIC) {
 192                 printk(badmagic, name, routine);
 193                 return 1;
 194         }
 195         return 0;
 196 }
 197
 198 /*
 199  * Add data to our pending-send buffers.
 200  *
 201  * NOTE: Don't use printk in here because it gets nastily recursive.
 202  * hvlog can be used to log to the hypervisor buffer
 203  */
 204 static int buffer_add(struct port_info *pi, const char *buf, size_t len)
 205 {
 206         size_t bleft;
 207         size_t curlen;
 208         const char *curbuf;
 209         int nextbuf;
 210
 211         curbuf = buf;
 212         bleft = len;
 213         while (bleft > 0) {
 214                 /*
 215                  * If there is no space left in the current buffer, we have
 216                  * filled everything up, so return.  If we filled the previous
 217                  * buffer we would already have moved to the next one.
 218                  */
 219                 if (pi->bufferBytes[pi->curbuf] == VIOCHAR_MAX_DATA) {
 220                         hvlog ("\n\rviocons: No overflow buffer available for memcpy().\n");
 221                         pi->bufferOverflow++;
 222                         pi->overflowMessage = 1;
 223                         break;
 224                 }
 225
 226                 /*
 227                  * Turn on the "used" bit for this buffer.  If it's already on,
 228                  * that's fine.
 229                  */
 230                 set_bit(pi->curbuf, &pi->used);
 231
 232                 /*
 233                  * See if this buffer has been allocated.  If not, allocate it.
 234                  */
 235                 if (pi->buffer[pi->curbuf] == NULL) {
 236                         pi->buffer[pi->curbuf] =
 237                             kmalloc(VIOCHAR_MAX_DATA, GFP_ATOMIC);
 238                         if (pi->buffer[pi->curbuf] == NULL) {
 239                                 hvlog("\n\rviocons: kmalloc failed allocating spaces for buffer %d.",
 240                                         pi->curbuf);
 241                                 break;
 242                         }
 243                 }
 244
 245                 /* Figure out how much we can copy into this buffer. */
 246                 if (bleft < (VIOCHAR_MAX_DATA - pi->bufferBytes[pi->curbuf]))
 247                         curlen = bleft;
 248                 else
 249                         curlen = VIOCHAR_MAX_DATA - pi->bufferBytes[pi->curbuf];
 250
 251                 /* Copy the data into the buffer. */
 252                 memcpy(pi->buffer[pi->curbuf] + pi->bufferBytes[pi->curbuf],
 253                                 curbuf, curlen);
 254
 255                 pi->bufferBytes[pi->curbuf] += curlen;
 256                 curbuf += curlen;
 257                 bleft -= curlen;
 258
 259                 /*
 260                  * Now see if we've filled this buffer.  If not then
 261                  * we'll try to use it again later.  If we've filled it
 262                  * up then we'll advance the curbuf to the next in the
 263                  * circular queue.
 264                  */
 265                 if (pi->bufferBytes[pi->curbuf] == VIOCHAR_MAX_DATA) {
 266                         nextbuf = (pi->curbuf + 1) % VIOCHAR_NUM_BUF;
 267                         /*
 268                          * Move to the next buffer if it hasn't been used yet
 269                          */
 270                         if (test_bit(nextbuf, &pi->used) == 0)
 271                                 pi->curbuf = nextbuf;
 272                 }
 273         }
 274         return len - bleft;
 275 }
 276
 277 /*
 278  * Send pending data
 279  *
 280  * NOTE: Don't use printk in here because it gets nastily recursive.
 281  * hvlog can be used to log to the hypervisor buffer
 282  */
 283 static void send_buffers(struct port_info *pi)
 284 {
 285         HvLpEvent_Rc hvrc;
 286         int nextbuf;
 287         struct viocharlpevent *viochar;
 288         unsigned long flags;
 289
 290         spin_lock_irqsave(&consolelock, flags);
 291
 292         viochar = (struct viocharlpevent *)
 293             vio_get_event_buffer(viomajorsubtype_chario);
 294
 295         /* Make sure we got a buffer */
 296         if (viochar == NULL) {
 297                 hvlog("\n\rviocons: Can't get viochar buffer in sendBuffers().");
 298                 spin_unlock_irqrestore(&consolelock, flags);
 299                 return;
 300         }
 301
 302         if (pi->used == 0) {
 303                 hvlog("\n\rviocons: in sendbuffers(), but no buffers used.\n");
 304                 vio_free_event_buffer(viomajorsubtype_chario, viochar);
 305                 spin_unlock_irqrestore(&consolelock, flags);
 306                 return;
 307         }
 308
 309         /*
 310          * curbuf points to the buffer we're filling.  We want to
 311          * start sending AFTER this one.
 312          */
 313         nextbuf = (pi->curbuf + 1) % VIOCHAR_NUM_BUF;
 314
 315         /*
 316          * Loop until we find a buffer with the used bit on
 317          */
 318         while (test_bit(nextbuf, &pi->used) == 0)
 319                 nextbuf = (nextbuf + 1) % VIOCHAR_NUM_BUF;
 320
 321         initDataEvent(viochar, pi->lp);
 322
 323         /*
 324          * While we have buffers with data, and our send window
 325          * is open, send them
 326          */
 327         while ((test_bit(nextbuf, &pi->used)) &&
 328                ((pi->seq - pi->ack) < VIOCHAR_WINDOW)) {
 329                 viochar->len = pi->bufferBytes[nextbuf];
 330                 viochar->event.xCorrelationToken = pi->seq++;
 331                 viochar->event.xSizeMinus1 =
 332                         offsetof(struct viocharlpevent, data) + viochar->len;
 333
 334                 memcpy(viochar->data, pi->buffer[nextbuf], viochar->len);
 335
 336                 hvrc = HvCallEvent_signalLpEvent(&viochar->event);
 337                 if (hvrc) {
 338                         /*
 339                          * MUST unlock the spinlock before doing a printk
 340                          */
 341                         vio_free_event_buffer(viomajorsubtype_chario, viochar);
 342                         spin_unlock_irqrestore(&consolelock, flags);
 343
 344                         printk(VIOCONS_KERN_WARN
 345                                "error sending event! return code %d\n",
 346                                (int)hvrc);
 347                         return;
 348                 }
 349
 350                 /*
 351                  * clear the used bit, zero the number of bytes in
 352                  * this buffer, and move to the next buffer
 353                  */
 354                 clear_bit(nextbuf, &pi->used);
 355                 pi->bufferBytes[nextbuf] = 0;
 356                 nextbuf = (nextbuf + 1) % VIOCHAR_NUM_BUF;
 357         }
 358
 359         /*
 360          * If we have emptied all the buffers, start at 0 again.
 361          * this will re-use any allocated buffers
 362          */
 363         if (pi->used == 0) {
 364                 pi->curbuf = 0;
 365
 366                 if (pi->overflowMessage)
 367                         pi->overflowMessage = 0;
 368
 369                 if (pi->tty) {
 370                         tty_wakeup(pi->tty);
 371                 }
 372         }
 373
 374         vio_free_event_buffer(viomajorsubtype_chario, viochar);
 375         spin_unlock_irqrestore(&consolelock, flags);
 376 }
 377
 378 /*
 379  * Our internal writer.  Gets called both from the console device and
 380  * the tty device.  the tty pointer will be NULL if called from the console.
 381  * Return total number of bytes "written".
 382  *
 383  * NOTE: Don't use printk in here because it gets nastily recursive.  hvlog
 384  * can be used to log to the hypervisor buffer
 385  */
 386 static int internal_write(struct port_info *pi, const char *buf, size_t len)
 387 {
 388         HvLpEvent_Rc hvrc;
 389         size_t bleft;
 390         size_t curlen;
 391         const char *curbuf;
 392         unsigned long flags;
 393         struct viocharlpevent *viochar;
 394
 395         /*
 396          * Write to the hvlog of inbound data are now done prior to
 397          * calling internal_write() since internal_write() is only called in
 398          * the event that an lp event path is active, which isn't the case for
 399          * logging attempts prior to console initialization.
 400          *
 401          * If there is already data queued for this port, send it prior to
 402          * attempting to send any new data.
 403          */
 404         if (pi->used)
 405                 send_buffers(pi);
 406
 407         spin_lock_irqsave(&consolelock, flags);
 408
 409         viochar = vio_get_event_buffer(viomajorsubtype_chario);
 410         if (viochar == NULL) {
 411                 spin_unlock_irqrestore(&consolelock, flags);
 412                 hvlog("\n\rviocons: Can't get vio buffer in internal_write().");
 413                 return -EAGAIN;
 414         }
 415         initDataEvent(viochar, pi->lp);
 416
 417         curbuf = buf;
 418         bleft = len;
 419
 420         while ((bleft > 0) && (pi->used == 0) &&
 421                ((pi->seq - pi->ack) < VIOCHAR_WINDOW)) {
 422                 if (bleft > VIOCHAR_MAX_DATA)
 423                         curlen = VIOCHAR_MAX_DATA;
 424                 else
 425                         curlen = bleft;
 426
 427                 viochar->event.xCorrelationToken = pi->seq++;
 428                 memcpy(viochar->data, curbuf, curlen);
 429                 viochar->len = curlen;
 430                 viochar->event.xSizeMinus1 =
 431                     offsetof(struct viocharlpevent, data) + curlen;
 432
 433                 hvrc = HvCallEvent_signalLpEvent(&viochar->event);
 434                 if (hvrc) {
 435                         hvlog("viocons: error sending event! %d\n", (int)hvrc);
 436                         goto out;
 437                 }
 438                 curbuf += curlen;
 439                 bleft -= curlen;
 440         }
 441
 442         /* If we didn't send it all, buffer as much of it as we can. */
 443         if (bleft > 0)
 444                 bleft -= buffer_add(pi, curbuf, bleft);
 445 out:
 446         vio_free_event_buffer(viomajorsubtype_chario, viochar);
 447         spin_unlock_irqrestore(&consolelock, flags);
 448         return len - bleft;
 449 }
 450
 451 static struct port_info *get_port_data(struct tty_struct *tty)
 452 {
 453         unsigned long flags;
 454         struct port_info *pi;
 455
 456         spin_lock_irqsave(&consolelock, flags);
 457         if (tty) {
 458                 pi = (struct port_info *)tty->driver_data;
 459                 if (!pi || viotty_paranoia_check(pi, tty->name,
 460                                              "get_port_data")) {
 461                         pi = NULL;
 462                 }
 463         } else
 464                 /*
 465                  * If this is the console device, use the lp from
 466                  * the first port entry
 467                  */
 468                 pi = &port_info[0];
 469         spin_unlock_irqrestore(&consolelock, flags);
 470         return pi;
 471 }
 472
 473 /*
 474  * Initialize the common fields in a charLpEvent
 475  */
 476 static void initDataEvent(struct viocharlpevent *viochar, HvLpIndex lp)
 477 {
 478         struct HvLpEvent *hev = &viochar->event;
 479
 480         memset(viochar, 0, sizeof(struct viocharlpevent));
 481
 482         hev->flags = HV_LP_EVENT_VALID | HV_LP_EVENT_DEFERRED_ACK |
 483                 HV_LP_EVENT_INT;
 484         hev->xType = HvLpEvent_Type_VirtualIo;
 485         hev->xSubtype = viomajorsubtype_chario | viochardata;
 486         hev->xSourceLp = HvLpConfig_getLpIndex();
 487         hev->xTargetLp = lp;
 488         hev->xSizeMinus1 = sizeof(struct viocharlpevent);
 489         hev->xSourceInstanceId = viopath_sourceinst(lp);
 490         hev->xTargetInstanceId = viopath_targetinst(lp);
 491 }
 492
 493 /*
 494  * early console device write
 495  */
 496 static void viocons_write_early(struct console *co, const char *s, unsigned count)
 497 {
 498         hvlogOutput(s, count);
 499 }
 500
 501 /*
 502  * console device write
 503  */
 504 static void viocons_write(struct console *co, const char *s, unsigned count)
 505 {
 506         int index;
 507         int begin;
 508         struct port_info *pi;
 509
 510         static const char cr = '\r';
 511
 512         /*
 513          * Check port data first because the target LP might be valid but
 514          * simply not active, in which case we want to hvlog the output.
 515          */
 516         pi = get_port_data(NULL);
 517         if (pi == NULL) {
 518                 hvlog("\n\rviocons_write: unable to get port data.");
 519                 return;
 520         }
 521
 522         hvlogOutput(s, count);
 523
 524         if (!viopath_isactive(pi->lp))
 525                 return;
 526
 527         /*
 528          * Any newline character found will cause a
 529          * carriage return character to be emitted as well.
 530          */
 531         begin = 0;
 532         for (index = 0; index < count; index++) {
 533                 if (s[index] == '\n') {
 534                         /*
 535                          * Newline found. Print everything up to and
 536                          * including the newline
 537                          */
 538                         internal_write(pi, &s[begin], index - begin + 1);
 539                         begin = index + 1;
 540                         /* Emit a carriage return as well */
 541                         internal_write(pi, &cr, 1);
 542                 }
 543         }
 544
 545         /* If any characters left to write, write them now */
 546         if ((index - begin) > 0)
 547                 internal_write(pi, &s[begin], index - begin);
 548 }
 549
 550 /*
 551  * Work out the device associate with this console
 552  */
 553 static struct tty_driver *viocons_device(struct console *c, int *index)
 554 {
 555         *index = c->index;
 556         return viotty_driver;
 557 }
 558
 559 /*
 560  * console device I/O methods
 561  */
 562 static struct console viocons_early = {
 563         .name = "viocons",
 564         .write = viocons_write_early,
 565         .flags = CON_PRINTBUFFER,
 566         .index = -1,
 567 };
 568
 569 static struct console viocons = {
 570         .name = "viocons",
 571         .write = viocons_write,
 572         .device = viocons_device,
 573         .flags = CON_PRINTBUFFER,
 574         .index = -1,
 575 };
 576
 577 /*
 578  * TTY Open method
 579  */
 580 static int viotty_open(struct tty_struct *tty, struct file *filp)
 581 {
 582         int port;
 583         unsigned long flags;
 584         struct port_info *pi;
 585
 586         port = tty->index;
 587
 588         if ((port < 0) || (port >= VTTY_PORTS))
 589                 return -ENODEV;
 590
 591         spin_lock_irqsave(&consolelock, flags);
 592
 593         pi = &port_info[port];
 594         /* If some other TTY is already connected here, reject the open */
 595         if ((pi->tty) && (pi->tty != tty)) {
 596                 spin_unlock_irqrestore(&consolelock, flags);
 597                 printk(VIOCONS_KERN_WARN
 598                        "attempt to open device twice from different ttys\n");
 599                 return -EBUSY;
 600         }
 601         tty->driver_data = pi;
 602         pi->tty = tty;
 603         spin_unlock_irqrestore(&consolelock, flags);
 604
 605         return 0;
 606 }
 607
 608 /*
 609  * TTY Close method
 610  */
 611 static void viotty_close(struct tty_struct *tty, struct file *filp)
 612 {
 613         unsigned long flags;
 614         struct port_info *pi;
 615
 616         spin_lock_irqsave(&consolelock, flags);
 617         pi = (struct port_info *)tty->driver_data;
 618
 619         if (!pi || viotty_paranoia_check(pi, tty->name, "viotty_close")) {
 620                 spin_unlock_irqrestore(&consolelock, flags);
 621                 return;
 622         }
 623         if (tty->count == 1)
 624                 pi->tty = NULL;
 625         spin_unlock_irqrestore(&consolelock, flags);
 626 }
 627
 628 /*
 629  * TTY Write method
 630  */
 631 static int viotty_write(struct tty_struct *tty, const unsigned char *buf,
 632                 int count)
 633 {
 634         struct port_info *pi;
 635
 636         pi = get_port_data(tty);
 637         if (pi == NULL) {
 638                 hvlog("\n\rviotty_write: no port data.");
 639                 return -ENODEV;
 640         }
 641
 642         if (viochar_is_console(pi))
 643                 hvlogOutput(buf, count);
 644
 645         /*
 646          * If the path to this LP is closed, don't bother doing anything more.
 647          * just dump the data on the floor and return count.  For some reason
 648          * some user level programs will attempt to probe available tty's and
 649          * they'll attempt a viotty_write on an invalid port which maps to an
 650          * invalid target lp.  If this is the case then ignore the
 651          * viotty_write call and, since the viopath isn't active to this
 652          * partition, return count.
 653          */
 654         if (!viopath_isactive(pi->lp))
 655                 return count;
 656
 657         return internal_write(pi, buf, count);
 658 }
 659
 660 /*
 661  * TTY put_char method
 662  */
 663 static void viotty_put_char(struct tty_struct *tty, unsigned char ch)
 664 {
 665         struct port_info *pi;
 666
 667         pi = get_port_data(tty);
 668         if (pi == NULL)
 669                 return;
 670
 671         /* This will append '\r' as well if the char is '\n' */
 672         if (viochar_is_console(pi))
 673                 hvlogOutput(&ch, 1);
 674
 675         if (viopath_isactive(pi->lp))
 676                 internal_write(pi, &ch, 1);
 677 }
 678
 679 /*
 680  * TTY write_room method
 681  */
 682 static int viotty_write_room(struct tty_struct *tty)
 683 {
 684         int i;
 685         int room = 0;
 686         struct port_info *pi;
 687         unsigned long flags;
 688
 689         spin_lock_irqsave(&consolelock, flags);
 690         pi = (struct port_info *)tty->driver_data;
 691         if (!pi || viotty_paranoia_check(pi, tty->name, "viotty_write_room")) {
 692                 spin_unlock_irqrestore(&consolelock, flags);
 693                 return 0;
 694         }
 695
 696         /* If no buffers are used, return the max size. */
 697         if (pi->used == 0) {
 698                 spin_unlock_irqrestore(&consolelock, flags);
 699                 return VIOCHAR_MAX_DATA * VIOCHAR_NUM_BUF;
 700         }
 701
 702         /*
 703          * We retain the spinlock because we want to get an accurate
 704          * count and it can change on us between each operation if we
 705          * don't hold the spinlock.
 706          */
 707         for (i = 0; ((i < VIOCHAR_NUM_BUF) && (room < VIOCHAR_MAX_DATA)); i++)
 708                 room += (VIOCHAR_MAX_DATA - pi->bufferBytes[i]);
 709         spin_unlock_irqrestore(&consolelock, flags);
 710
 711         if (room > VIOCHAR_MAX_DATA)
 712                 room = VIOCHAR_MAX_DATA;
 713         return room;
 714 }
 715
 716 /*
 717  * TTY chars_in_buffer method
 718  */
 719 static int viotty_chars_in_buffer(struct tty_struct *tty)
 720 {
 721         return 0;
 722 }
 723
 724 static int viotty_ioctl(struct tty_struct *tty, struct file *file,
 725                         unsigned int cmd, unsigned long arg)
 726 {
 727         switch (cmd) {
 728         /*
 729          * the ioctls below read/set the flags usually shown in the leds
 730          * don't use them - they will go away without warning
 731          */
 732         case KDGETLED:
 733         case KDGKBLED:
 734                 return put_user(0, (char *)arg);
 735
 736         case KDSKBLED:
 737                 return 0;
 738         }
 739
 740         return n_tty_ioctl(tty, file, cmd, arg);
 741 }
 742
 743 /*
 744  * Handle an open charLpEvent.  Could be either interrupt or ack
 745  */
 746 static void vioHandleOpenEvent(struct HvLpEvent *event)
 747 {
 748         unsigned long flags;
 749         struct viocharlpevent *cevent = (struct viocharlpevent *)event;
 750         u8 port = cevent->virtual_device;
 751         struct port_info *pi;
 752         int reject = 0;
 753
 754         if (hvlpevent_is_ack(event)) {
 755                 if (port >= VTTY_PORTS)
 756                         return;
 757
 758                 spin_lock_irqsave(&consolelock, flags);
 759                 /* Got the lock, don't cause console output */
 760
 761                 pi = &port_info[port];
 762                 if (event->xRc == HvLpEvent_Rc_Good) {
 763                         pi->seq = pi->ack = 0;
 764                         /*
 765                          * This line allows connections from the primary
 766                          * partition but once one is connected from the
 767                          * primary partition nothing short of a reboot
 768                          * of linux will allow access from the hosting
 769                          * partition again without a required iSeries fix.
 770                          */
 771                         pi->lp = event->xTargetLp;
 772                 }
 773
 774                 spin_unlock_irqrestore(&consolelock, flags);
 775                 if (event->xRc != HvLpEvent_Rc_Good)
 776                         printk(VIOCONS_KERN_WARN
 777                                "handle_open_event: event->xRc == (%d).\n",
 778                                event->xRc);
 779
 780                 if (event->xCorrelationToken != 0) {
 781                         atomic_t *aptr= (atomic_t *)event->xCorrelationToken;
 782                         atomic_set(aptr, 1);
 783                 } else
 784                         printk(VIOCONS_KERN_WARN
 785                                "weird...got open ack without atomic\n");
 786                 return;
 787         }
 788
 789         /* This had better require an ack, otherwise complain */
 790         if (!hvlpevent_need_ack(event)) {
 791                 printk(VIOCONS_KERN_WARN "viocharopen without ack bit!\n");
 792                 return;
 793         }
 794
 795         spin_lock_irqsave(&consolelock, flags);
 796         /* Got the lock, don't cause console output */
 797
 798         /* Make sure this is a good virtual tty */
 799         if (port >= VTTY_PORTS) {
 800                 event->xRc = HvLpEvent_Rc_SubtypeError;
 801                 cevent->subtype_result_code = viorc_openRejected;
 802                 /*
 803                  * Flag state here since we can't printk while holding
 804                  * a spinlock.
 805                  */
 806                 reject = 1;
 807         } else {
 808                 pi = &port_info[port];
 809                 if ((pi->lp != HvLpIndexInvalid) &&
 810                                 (pi->lp != event->xSourceLp)) {
 811                         /*
 812                          * If this is tty is already connected to a different
 813                          * partition, fail.
 814                          */
 815                         event->xRc = HvLpEvent_Rc_SubtypeError;
 816                         cevent->subtype_result_code = viorc_openRejected;
 817                         reject = 2;
 818                 } else {
 819                         pi->lp = event->xSourceLp;
 820                         event->xRc = HvLpEvent_Rc_Good;
 821                         cevent->subtype_result_code = viorc_good;
 822                         pi->seq = pi->ack = 0;
 823                         reject = 0;
 824                 }
 825         }
 826
 827         spin_unlock_irqrestore(&consolelock, flags);
 828
 829         if (reject == 1)
 830                 printk(VIOCONS_KERN_WARN "open rejected: bad virtual tty.\n");
 831         else if (reject == 2)
 832                 printk(VIOCONS_KERN_WARN
 833                         "open rejected: console in exclusive use by another partition.\n");
 834
 835         /* Return the acknowledgement */
 836         HvCallEvent_ackLpEvent(event);
 837 }
 838
 839 /*
 840  * Handle a close charLpEvent.  This should ONLY be an Interrupt because the
 841  * virtual console should never actually issue a close event to the hypervisor
 842  * because the virtual console never goes away.  A close event coming from the
 843  * hypervisor simply means that there are no client consoles connected to the
 844  * virtual console.
 845  *
 846  * Regardless of the number of connections masqueraded on the other side of
 847  * the hypervisor ONLY ONE close event should be called to accompany the ONE
 848  * open event that is called.  The close event should ONLY be called when NO
 849  * MORE connections (masqueraded or not) exist on the other side of the
 850  * hypervisor.
 851  */
 852 static void vioHandleCloseEvent(struct HvLpEvent *event)
 853 {
 854         unsigned long flags;
 855         struct viocharlpevent *cevent = (struct viocharlpevent *)event;
 856         u8 port = cevent->virtual_device;
 857
 858         if (hvlpevent_is_int(event)) {
 859                 if (port >= VTTY_PORTS) {
 860                         printk(VIOCONS_KERN_WARN
 861                                         "close message from invalid virtual device.\n");
 862                         return;
 863                 }
 864
 865                 /* For closes, just mark the console partition invalid */
 866                 spin_lock_irqsave(&consolelock, flags);
 867                 /* Got the lock, don't cause console output */
 868
 869                 if (port_info[port].lp == event->xSourceLp)
 870                         port_info[port].lp = HvLpIndexInvalid;
 871
 872                 spin_unlock_irqrestore(&consolelock, flags);
 873                 printk(VIOCONS_KERN_INFO "close from %d\n", event->xSourceLp);
 874         } else
 875                 printk(VIOCONS_KERN_WARN
 876                                 "got unexpected close acknowlegement\n");
 877 }
 878
 879 /*
 880  * Handle a config charLpEvent.  Could be either interrupt or ack
 881  */
 882 static void vioHandleConfig(struct HvLpEvent *event)
 883 {
 884         struct viocharlpevent *cevent = (struct viocharlpevent *)event;
 885
 886         HvCall_writeLogBuffer(cevent->data, cevent->len);
 887
 888         if (cevent->data[0] == 0x01)
 889                 printk(VIOCONS_KERN_INFO "window resized to %d: %d: %d: %d\n",
 890                        cevent->data[1], cevent->data[2],
 891                        cevent->data[3], cevent->data[4]);
 892         else
 893                 printk(VIOCONS_KERN_WARN "unknown config event\n");
 894 }
 895
 896 /*
 897  * Handle a data charLpEvent.
 898  */
 899 static void vioHandleData(struct HvLpEvent *event)
 900 {
 901         struct tty_struct *tty;
 902         unsigned long flags;
 903         struct viocharlpevent *cevent = (struct viocharlpevent *)event;
 904         struct port_info *pi;
 905         int index;
 906         int num_pushed;
 907         u8 port = cevent->virtual_device;
 908
 909         if (port >= VTTY_PORTS) {
 910                 printk(VIOCONS_KERN_WARN "data on invalid virtual device %d\n",
 911                                 port);
 912                 return;
 913         }
 914
 915         /*
 916          * Hold the spinlock so that we don't take an interrupt that
 917          * changes tty between the time we fetch the port_info
 918          * pointer and the time we paranoia check.
 919          */
 920         spin_lock_irqsave(&consolelock, flags);
 921         pi = &port_info[port];
 922
 923         /*
 924          * Change 05/01/2003 - Ryan Arnold: If a partition other than
 925          * the current exclusive partition tries to send us data
 926          * events then just drop them on the floor because we don't
 927          * want his stinking data.  He isn't authorized to receive
 928          * data because he wasn't the first one to get the console,
 929          * therefore he shouldn't be allowed to send data either.
 930          * This will work without an iSeries fix.
 931          */
 932         if (pi->lp != event->xSourceLp) {
 933                 spin_unlock_irqrestore(&consolelock, flags);
 934                 return;
 935         }
 936
 937         tty = pi->tty;
 938         if (tty == NULL) {
 939                 spin_unlock_irqrestore(&consolelock, flags);
 940                 printk(VIOCONS_KERN_WARN "no tty for virtual device %d\n",
 941                                 port);
 942                 return;
 943         }
 944
 945         if (tty->magic != TTY_MAGIC) {
 946                 spin_unlock_irqrestore(&consolelock, flags);
 947                 printk(VIOCONS_KERN_WARN "tty bad magic\n");
 948                 return;
 949         }
 950
 951         /*
 952          * Just to be paranoid, make sure the tty points back to this port
 953          */
 954         pi = (struct port_info *)tty->driver_data;
 955         if (!pi || viotty_paranoia_check(pi, tty->name, "vioHandleData")) {
 956                 spin_unlock_irqrestore(&consolelock, flags);
 957                 return;
 958         }
 959         spin_unlock_irqrestore(&consolelock, flags);
 960
 961         /*
 962          * Change 07/21/2003 - Ryan Arnold: functionality added to
 963          * support sysrq utilizing ^O as the sysrq key.  The sysrq
 964          * functionality will only work if built into the kernel and
 965          * then only if sysrq is enabled through the proc filesystem.
 966          */
 967         num_pushed = 0;
 968         for (index = 0; index < cevent->len; index++) {
 969 #ifdef CONFIG_MAGIC_SYSRQ
 970                 if (sysrq_enabled) {
 971                         /* 0x0f is the ascii character for ^O */
 972                         if (cevent->data[index] == '\x0f') {
 973                                 vio_sysrq_pressed = 1;
 974                                 /*
 975                                  * continue because we don't want to add
 976                                  * the sysrq key into the data string.
 977                                  */
 978                                 continue;
 979                         } else if (vio_sysrq_pressed) {
 980                                 handle_sysrq(cevent->data[index], NULL, tty);
 981                                 vio_sysrq_pressed = 0;
 982                                 /*
 983                                  * continue because we don't want to add
 984                                  * the sysrq sequence into the data string.
 985                                  */
 986                                 continue;
 987                         }
 988                 }
 989 #endif
 990                 /*
 991                  * The sysrq sequence isn't included in this check if
 992                  * sysrq is enabled and compiled into the kernel because
 993                  * the sequence will never get inserted into the buffer.
 994                  * Don't attempt to copy more data into the buffer than we
 995                  * have room for because it would fail without indication.
 996                  */
 997                 if(tty_insert_flip_char(tty, cevent->data[index], TTY_NORMAL) == 0) {
 998                         printk(VIOCONS_KERN_WARN "input buffer overflow!\n");
 999                         break;
1000                 }
1001                 num_pushed++;
1002         }
1003
1004         if (num_pushed)
1005                 tty_flip_buffer_push(tty);
1006 }
1007
1008 /*
1009  * Handle an ack charLpEvent.
1010  */
1011 static void vioHandleAck(struct HvLpEvent *event)
1012 {
1013         struct viocharlpevent *cevent = (struct viocharlpevent *)event;
1014         unsigned long flags;
1015         u8 port = cevent->virtual_device;
1016
1017         if (port >= VTTY_PORTS) {
1018                 printk(VIOCONS_KERN_WARN "data on invalid virtual device\n");
1019                 return;
1020         }
1021
1022         spin_lock_irqsave(&consolelock, flags);
1023         port_info[port].ack = event->xCorrelationToken;
1024         spin_unlock_irqrestore(&consolelock, flags);
1025
1026         if (port_info[port].used)
1027                 send_buffers(&port_info[port]);
1028 }
1029
1030 /*
1031  * Handle charLpEvents and route to the appropriate routine
1032  */
1033 static void vioHandleCharEvent(struct HvLpEvent *event)
1034 {
1035         int charminor;
1036
1037         if (event == NULL)
1038                 return;
1039
1040         charminor = event->xSubtype & VIOMINOR_SUBTYPE_MASK;
1041         switch (charminor) {
1042         case viocharopen:
1043                 vioHandleOpenEvent(event);
1044                 break;
1045         case viocharclose:
1046                 vioHandleCloseEvent(event);
1047                 break;
1048         case viochardata:
1049                 vioHandleData(event);
1050                 break;
1051         case viocharack:
1052                 vioHandleAck(event);
1053                 break;
1054         case viocharconfig:
1055                 vioHandleConfig(event);
1056                 break;
1057         default:
1058                 if (hvlpevent_is_int(event) && hvlpevent_need_ack(event)) {
1059                         event->xRc = HvLpEvent_Rc_InvalidSubtype;
1060                         HvCallEvent_ackLpEvent(event);
1061                 }
1062         }
1063 }
1064
1065 /*
1066  * Send an open event
1067  */
1068 static int send_open(HvLpIndex remoteLp, void *sem)
1069 {
1070         return HvCallEvent_signalLpEventFast(remoteLp,
1071                         HvLpEvent_Type_VirtualIo,
1072                         viomajorsubtype_chario | viocharopen,
1073                         HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
1074                         viopath_sourceinst(remoteLp),
1075                         viopath_targetinst(remoteLp),
1076                         (u64)(unsigned long)sem, VIOVERSION << 16,
1077                         0, 0, 0, 0);
1078 }
1079
1080 static struct tty_operations serial_ops = {
1081         .open = viotty_open,
1082         .close = viotty_close,
1083         .write = viotty_write,
1084         .put_char = viotty_put_char,
1085         .write_room = viotty_write_room,
1086         .chars_in_buffer = viotty_chars_in_buffer,
1087         .ioctl = viotty_ioctl,
1088 };
1089
1090 static int __init viocons_init2(void)
1091 {
1092         atomic_t wait_flag;
1093         int rc;
1094
1095         /* +2 for fudge */
1096         rc = viopath_open(HvLpConfig_getPrimaryLpIndex(),
1097                         viomajorsubtype_chario, VIOCHAR_WINDOW + 2);
1098         if (rc)
1099                 printk(VIOCONS_KERN_WARN "error opening to primary %d\n", rc);
1100
1101         if (viopath_hostLp == HvLpIndexInvalid)
1102                 vio_set_hostlp();
1103
1104         /*
1105          * And if the primary is not the same as the hosting LP, open to the
1106          * hosting lp
1107          */
1108         if ((viopath_hostLp != HvLpIndexInvalid) &&
1109             (viopath_hostLp != HvLpConfig_getPrimaryLpIndex())) {
1110                 printk(VIOCONS_KERN_INFO "open path to hosting (%d)\n",
1111                                 viopath_hostLp);
1112                 rc = viopath_open(viopath_hostLp, viomajorsubtype_chario,
1113                                 VIOCHAR_WINDOW + 2);    /* +2 for fudge */
1114                 if (rc)
1115                         printk(VIOCONS_KERN_WARN
1116                                 "error opening to partition %d: %d\n",
1117                                 viopath_hostLp, rc);
1118         }
1119
1120         if (vio_setHandler(viomajorsubtype_chario, vioHandleCharEvent) < 0)
1121                 printk(VIOCONS_KERN_WARN
1122                                 "error seting handler for console events!\n");
1123
1124         /*
1125          * First, try to open the console to the hosting lp.
1126          * Wait on a semaphore for the response.
1127          */
1128         atomic_set(&wait_flag, 0);
1129         if ((viopath_isactive(viopath_hostLp)) &&
1130             (send_open(viopath_hostLp, (void *)&wait_flag) == 0)) {
1131                 printk(VIOCONS_KERN_INFO "hosting partition %d\n",
1132                         viopath_hostLp);
1133                 while (atomic_read(&wait_flag) == 0)
1134                         mb();
1135                 atomic_set(&wait_flag, 0);
1136         }
1137
1138         /*
1139          * If we don't have an active console, try the primary
1140          */
1141         if ((!viopath_isactive(port_info[0].lp)) &&
1142             (viopath_isactive(HvLpConfig_getPrimaryLpIndex())) &&
1143             (send_open(HvLpConfig_getPrimaryLpIndex(), (void *)&wait_flag)
1144              == 0)) {
1145                 printk(VIOCONS_KERN_INFO "opening console to primary partition\n");
1146                 while (atomic_read(&wait_flag) == 0)
1147                         mb();
1148         }
1149
1150         /* Initialize the tty_driver structure */
1151         viotty_driver = alloc_tty_driver(VTTY_PORTS);
1152         viotty_driver->owner = THIS_MODULE;
1153         viotty_driver->driver_name = "vioconsole";
1154         viotty_driver->name = "tty";
1155         viotty_driver->name_base = 1;
1156         viotty_driver->major = TTY_MAJOR;
1157         viotty_driver->minor_start = 1;
1158         viotty_driver->type = TTY_DRIVER_TYPE_CONSOLE;
1159         viotty_driver->subtype = 1;
1160         viotty_driver->init_termios = tty_std_termios;
1161         viotty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
1162         tty_set_operations(viotty_driver, &serial_ops);
1163
1164         if (tty_register_driver(viotty_driver)) {
1165                 printk(VIOCONS_KERN_WARN "couldn't register console driver\n");
1166                 put_tty_driver(viotty_driver);
1167                 viotty_driver = NULL;
1168         }
1169
1170         unregister_console(&viocons_early);
1171         register_console(&viocons);
1172
1173         return 0;
1174 }
1175
1176 static int __init viocons_init(void)
1177 {
1178         int i;
1179
1180         printk(VIOCONS_KERN_INFO "registering console\n");
1181         for (i = 0; i < VTTY_PORTS; i++) {
1182                 port_info[i].lp = HvLpIndexInvalid;
1183                 port_info[i].magic = VIOTTY_MAGIC;
1184         }
1185         HvCall_setLogBufferFormatAndCodepage(HvCall_LogBuffer_ASCII, 437);
1186         register_console(&viocons_early);
1187         return 0;
1188 }
1189
1190 console_initcall(viocons_init);
1191 module_init(viocons_init2);