drivers/char/hvc_iucv.c

   1 /*
   2  * hvc_iucv.c - z/VM IUCV hypervisor console (HVC) device driver
   3  *
   4  * This HVC device driver provides terminal access using
   5  * z/VM IUCV communication paths.
   6  *
   7  * Copyright IBM Corp. 2008
   8  *
   9  * Author(s):   Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
  10  */
  11 #define KMSG_COMPONENT          "hvc_iucv"
  12 #define pr_fmt(fmt)             KMSG_COMPONENT ": " fmt
  13
  14 #include <linux/types.h>
  15 #include <asm/ebcdic.h>
  16 #include <linux/delay.h>
  17 #include <linux/init.h>
  18 #include <linux/mempool.h>
  19 #include <linux/module.h>
  20 #include <linux/tty.h>
  21 #include <linux/wait.h>
  22 #include <net/iucv/iucv.h>
  23
  24 #include "hvc_console.h"
  25
  26
  27 /* General device driver settings */
  28 #define HVC_IUCV_MAGIC          0xc9e4c3e5
  29 #define MAX_HVC_IUCV_LINES      HVC_ALLOC_TTY_ADAPTERS
  30 #define MEMPOOL_MIN_NR          (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
  31
  32 /* IUCV TTY message  */
  33 #define MSG_VERSION             0x02    /* Message version */
  34 #define MSG_TYPE_ERROR          0x01    /* Error message */
  35 #define MSG_TYPE_TERMENV        0x02    /* Terminal environment variable */
  36 #define MSG_TYPE_TERMIOS        0x04    /* Terminal IO struct update */
  37 #define MSG_TYPE_WINSIZE        0x08    /* Terminal window size update */
  38 #define MSG_TYPE_DATA           0x10    /* Terminal data */
  39
  40 struct iucv_tty_msg {
  41         u8      version;                /* Message version */
  42         u8      type;                   /* Message type */
  43 #define MSG_MAX_DATALEN         ((u16)(~0))
  44         u16     datalen;                /* Payload length */
  45         u8      data[];                 /* Payload buffer */
  46 } __attribute__((packed));
  47 #define MSG_SIZE(s)             ((s) + offsetof(struct iucv_tty_msg, data))
  48
  49 enum iucv_state_t {
  50         IUCV_DISCONN    = 0,
  51         IUCV_CONNECTED  = 1,
  52         IUCV_SEVERED    = 2,
  53 };
  54
  55 enum tty_state_t {
  56         TTY_CLOSED      = 0,
  57         TTY_OPENED      = 1,
  58 };
  59
  60 struct hvc_iucv_private {
  61         struct hvc_struct       *hvc;           /* HVC struct reference */
  62         u8                      srv_name[8];    /* IUCV service name (ebcdic) */
  63         enum iucv_state_t       iucv_state;     /* IUCV connection status */
  64         enum tty_state_t        tty_state;      /* TTY status */
  65         struct iucv_path        *path;          /* IUCV path pointer */
  66         spinlock_t              lock;           /* hvc_iucv_private lock */
  67 #define SNDBUF_SIZE             (PAGE_SIZE)     /* must be < MSG_MAX_DATALEN */
  68         void                    *sndbuf;        /* send buffer            */
  69         size_t                  sndbuf_len;     /* length of send buffer  */
  70 #define QUEUE_SNDBUF_DELAY      (HZ / 25)
  71         struct delayed_work     sndbuf_work;    /* work: send iucv msg(s) */
  72         wait_queue_head_t       sndbuf_waitq;   /* wait for send completion */
  73         struct list_head        tty_outqueue;   /* outgoing IUCV messages */
  74         struct list_head        tty_inqueue;    /* incoming IUCV messages */
  75 };
  76
  77 struct iucv_tty_buffer {
  78         struct list_head        list;   /* list pointer */
  79         struct iucv_message     msg;    /* store an IUCV message */
  80         size_t                  offset; /* data buffer offset */
  81         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
  82 };
  83
  84 /* IUCV callback handler */
  85 static  int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
  86 static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
  87 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  88 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  89
  90
  91 /* Kernel module parameter: use one terminal device as default */
  92 static unsigned long hvc_iucv_devices = 1;
  93
  94 /* Array of allocated hvc iucv tty lines... */
  95 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
  96
  97 /* Kmem cache and mempool for iucv_tty_buffer elements */
  98 static struct kmem_cache *hvc_iucv_buffer_cache;
  99 static mempool_t *hvc_iucv_mempool;
 100
 101 /* IUCV handler callback functions */
 102 static struct iucv_handler hvc_iucv_handler = {
 103         .path_pending  = hvc_iucv_path_pending,
 104         .path_severed  = hvc_iucv_path_severed,
 105         .message_complete = hvc_iucv_msg_complete,
 106         .message_pending  = hvc_iucv_msg_pending,
 107 };
 108
 109
 110 /**
 111  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
 112  * @num:        The HVC virtual terminal number (vtermno)
 113  *
 114  * This function returns the struct hvc_iucv_private instance that corresponds
 115  * to the HVC virtual terminal number specified as parameter @num.
 116  */
 117 struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
 118 {
 119         if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
 120                 return NULL;
 121         return hvc_iucv_table[num - HVC_IUCV_MAGIC];
 122 }
 123
 124 /**
 125  * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
 126  * @size:       Size of the internal buffer used to store data.
 127  * @flags:      Memory allocation flags passed to mempool.
 128  *
 129  * This function allocates a new struct iucv_tty_buffer element and, optionally,
 130  * allocates an internal data buffer with the specified size @size.
 131  * Note: The total message size arises from the internal buffer size and the
 132  *       members of the iucv_tty_msg structure.
 133  * The function returns NULL if memory allocation has failed.
 134  */
 135 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
 136 {
 137         struct iucv_tty_buffer *bufp;
 138
 139         bufp = mempool_alloc(hvc_iucv_mempool, flags);
 140         if (!bufp)
 141                 return NULL;
 142         memset(bufp, 0, sizeof(struct iucv_tty_buffer));
 143
 144         if (size > 0) {
 145                 bufp->msg.length = MSG_SIZE(size);
 146                 bufp->mbuf = kmalloc(bufp->msg.length, flags);
 147                 if (!bufp->mbuf) {
 148                         mempool_free(bufp, hvc_iucv_mempool);
 149                         return NULL;
 150                 }
 151                 bufp->mbuf->version = MSG_VERSION;
 152                 bufp->mbuf->type    = MSG_TYPE_DATA;
 153                 bufp->mbuf->datalen = (u16) size;
 154         }
 155         return bufp;
 156 }
 157
 158 /**
 159  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
 160  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
 161  */
 162 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
 163 {
 164         kfree(bufp->mbuf);
 165         mempool_free(bufp, hvc_iucv_mempool);
 166 }
 167
 168 /**
 169  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
 170  * @list:       List containing struct iucv_tty_buffer elements.
 171  */
 172 static void destroy_tty_buffer_list(struct list_head *list)
 173 {
 174         struct iucv_tty_buffer *ent, *next;
 175
 176         list_for_each_entry_safe(ent, next, list, list) {
 177                 list_del(&ent->list);
 178                 destroy_tty_buffer(ent);
 179         }
 180 }
 181
 182 /**
 183  * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
 184  * @priv:               Pointer to struct hvc_iucv_private
 185  * @buf:                HVC buffer for writing received terminal data.
 186  * @count:              HVC buffer size.
 187  * @has_more_data:      Pointer to an int variable.
 188  *
 189  * The function picks up pending messages from the input queue and receives
 190  * the message data that is then written to the specified buffer @buf.
 191  * If the buffer size @count is less than the data message size, the
 192  * message is kept on the input queue and @has_more_data is set to 1.
 193  * If all message data has been written, the message is removed from
 194  * the input queue.
 195  *
 196  * The function returns the number of bytes written to the terminal, zero if
 197  * there are no pending data messages available or if there is no established
 198  * IUCV path.
 199  * If the IUCV path has been severed, then -EPIPE is returned to cause a
 200  * hang up (that is issued by the HVC layer).
 201  */
 202 static int hvc_iucv_write(struct hvc_iucv_private *priv,
 203                           char *buf, int count, int *has_more_data)
 204 {
 205         struct iucv_tty_buffer *rb;
 206         int written;
 207         int rc;
 208
 209         /* immediately return if there is no IUCV connection */
 210         if (priv->iucv_state == IUCV_DISCONN)
 211                 return 0;
 212
 213         /* if the IUCV path has been severed, return -EPIPE to inform the
 214          * HVC layer to hang up the tty device. */
 215         if (priv->iucv_state == IUCV_SEVERED)
 216                 return -EPIPE;
 217
 218         /* check if there are pending messages */
 219         if (list_empty(&priv->tty_inqueue))
 220                 return 0;
 221
 222         /* receive an iucv message and flip data to the tty (ldisc) */
 223         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
 224
 225         written = 0;
 226         if (!rb->mbuf) { /* message not yet received ... */
 227                 /* allocate mem to store msg data; if no memory is available
 228                  * then leave the buffer on the list and re-try later */
 229                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC);
 230                 if (!rb->mbuf)
 231                         return -ENOMEM;
 232
 233                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
 234                                             rb->mbuf, rb->msg.length, NULL);
 235                 switch (rc) {
 236                 case 0: /* Successful       */
 237                         break;
 238                 case 2: /* No message found */
 239                 case 9: /* Message purged   */
 240                         break;
 241                 default:
 242                         written = -EIO;
 243                 }
 244                 /* remove buffer if an error has occured or received data
 245                  * is not correct */
 246                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
 247                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
 248                         goto out_remove_buffer;
 249         }
 250
 251         switch (rb->mbuf->type) {
 252         case MSG_TYPE_DATA:
 253                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
 254                 memcpy(buf, rb->mbuf->data + rb->offset, written);
 255                 if (written < (rb->mbuf->datalen - rb->offset)) {
 256                         rb->offset += written;
 257                         *has_more_data = 1;
 258                         goto out_written;
 259                 }
 260                 break;
 261
 262         case MSG_TYPE_WINSIZE:
 263                 if (rb->mbuf->datalen != sizeof(struct winsize))
 264                         break;
 265                 hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
 266                 break;
 267
 268         case MSG_TYPE_ERROR:    /* ignored ... */
 269         case MSG_TYPE_TERMENV:  /* ignored ... */
 270         case MSG_TYPE_TERMIOS:  /* ignored ... */
 271                 break;
 272         }
 273
 274 out_remove_buffer:
 275         list_del(&rb->list);
 276         destroy_tty_buffer(rb);
 277         *has_more_data = !list_empty(&priv->tty_inqueue);
 278
 279 out_written:
 280         return written;
 281 }
 282
 283 /**
 284  * hvc_iucv_get_chars() - HVC get_chars operation.
 285  * @vtermno:    HVC virtual terminal number.
 286  * @buf:        Pointer to a buffer to store data
 287  * @count:      Size of buffer available for writing
 288  *
 289  * The HVC thread calls this method to read characters from the back-end.
 290  * If an IUCV communication path has been established, pending IUCV messages
 291  * are received and data is copied into buffer @buf up to @count bytes.
 292  *
 293  * Locking:     The routine gets called under an irqsave() spinlock; and
 294  *              the routine locks the struct hvc_iucv_private->lock to call
 295  *              helper functions.
 296  */
 297 static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
 298 {
 299         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 300         int written;
 301         int has_more_data;
 302
 303         if (count <= 0)
 304                 return 0;
 305
 306         if (!priv)
 307                 return -ENODEV;
 308
 309         spin_lock(&priv->lock);
 310         has_more_data = 0;
 311         written = hvc_iucv_write(priv, buf, count, &has_more_data);
 312         spin_unlock(&priv->lock);
 313
 314         /* if there are still messages on the queue... schedule another run */
 315         if (has_more_data)
 316                 hvc_kick();
 317
 318         return written;
 319 }
 320
 321 /**
 322  * hvc_iucv_queue() - Buffer terminal data for sending.
 323  * @priv:       Pointer to struct hvc_iucv_private instance.
 324  * @buf:        Buffer containing data to send.
 325  * @count:      Size of buffer and amount of data to send.
 326  *
 327  * The function queues data for sending. To actually send the buffered data,
 328  * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
 329  * The function returns the number of data bytes that has been buffered.
 330  *
 331  * If the device is not connected, data is ignored and the function returns
 332  * @count.
 333  * If the buffer is full, the function returns 0.
 334  * If an existing IUCV communicaton path has been severed, -EPIPE is returned
 335  * (that can be passed to HVC layer to cause a tty hangup).
 336  */
 337 static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
 338                           int count)
 339 {
 340         size_t len;
 341
 342         if (priv->iucv_state == IUCV_DISCONN)
 343                 return count;                   /* ignore data */
 344
 345         if (priv->iucv_state == IUCV_SEVERED)
 346                 return -EPIPE;
 347
 348         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
 349         if (!len)
 350                 return 0;
 351
 352         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
 353         priv->sndbuf_len += len;
 354
 355         if (priv->iucv_state == IUCV_CONNECTED)
 356                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
 357
 358         return len;
 359 }
 360
 361 /**
 362  * hvc_iucv_send() - Send an IUCV message containing terminal data.
 363  * @priv:       Pointer to struct hvc_iucv_private instance.
 364  *
 365  * If an IUCV communication path has been established, the buffered output data
 366  * is sent via an IUCV message and the number of bytes sent is returned.
 367  * Returns 0 if there is no established IUCV communication path or
 368  * -EPIPE if an existing IUCV communicaton path has been severed.
 369  */
 370 static int hvc_iucv_send(struct hvc_iucv_private *priv)
 371 {
 372         struct iucv_tty_buffer *sb;
 373         int rc, len;
 374
 375         if (priv->iucv_state == IUCV_SEVERED)
 376                 return -EPIPE;
 377
 378         if (priv->iucv_state == IUCV_DISCONN)
 379                 return -EIO;
 380
 381         if (!priv->sndbuf_len)
 382                 return 0;
 383
 384         /* allocate internal buffer to store msg data and also compute total
 385          * message length */
 386         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
 387         if (!sb)
 388                 return -ENOMEM;
 389
 390         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
 391         sb->mbuf->datalen = (u16) priv->sndbuf_len;
 392         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
 393
 394         list_add_tail(&sb->list, &priv->tty_outqueue);
 395
 396         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
 397                                  (void *) sb->mbuf, sb->msg.length);
 398         if (rc) {
 399                 /* drop the message here; however we might want to handle
 400                  * 0x03 (msg limit reached) by trying again... */
 401                 list_del(&sb->list);
 402                 destroy_tty_buffer(sb);
 403         }
 404         len = priv->sndbuf_len;
 405         priv->sndbuf_len = 0;
 406
 407         return len;
 408 }
 409
 410 /**
 411  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
 412  * @work:       Work structure.
 413  *
 414  * This work queue function sends buffered output data over IUCV and,
 415  * if not all buffered data could be sent, reschedules itself.
 416  */
 417 static void hvc_iucv_sndbuf_work(struct work_struct *work)
 418 {
 419         struct hvc_iucv_private *priv;
 420
 421         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 422         if (!priv)
 423                 return;
 424
 425         spin_lock_bh(&priv->lock);
 426         hvc_iucv_send(priv);
 427         spin_unlock_bh(&priv->lock);
 428 }
 429
 430 /**
 431  * hvc_iucv_put_chars() - HVC put_chars operation.
 432  * @vtermno:    HVC virtual terminal number.
 433  * @buf:        Pointer to an buffer to read data from
 434  * @count:      Size of buffer available for reading
 435  *
 436  * The HVC thread calls this method to write characters to the back-end.
 437  * The function calls hvc_iucv_queue() to queue terminal data for sending.
 438  *
 439  * Locking:     The method gets called under an irqsave() spinlock; and
 440  *              locks struct hvc_iucv_private->lock.
 441  */
 442 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 443 {
 444         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 445         int queued;
 446
 447         if (count <= 0)
 448                 return 0;
 449
 450         if (!priv)
 451                 return -ENODEV;
 452
 453         spin_lock(&priv->lock);
 454         queued = hvc_iucv_queue(priv, buf, count);
 455         spin_unlock(&priv->lock);
 456
 457         return queued;
 458 }
 459
 460 /**
 461  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 462  * @hp: Pointer to the HVC device (struct hvc_struct)
 463  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 464  *      hvc_iucv_private instance.
 465  *
 466  * The function sets the tty state to TTY_OPEN for the struct hvc_iucv_private
 467  * instance that is derived from @id. Always returns 0.
 468  *
 469  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
 470  */
 471 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 472 {
 473         struct hvc_iucv_private *priv;
 474
 475         priv = hvc_iucv_get_private(id);
 476         if (!priv)
 477                 return 0;
 478
 479         spin_lock_bh(&priv->lock);
 480         priv->tty_state = TTY_OPENED;
 481         spin_unlock_bh(&priv->lock);
 482
 483         return 0;
 484 }
 485
 486 /**
 487  * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 488  * @priv:       Pointer to the struct hvc_iucv_private instance.
 489  */
 490 static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 491 {
 492         destroy_tty_buffer_list(&priv->tty_outqueue);
 493         destroy_tty_buffer_list(&priv->tty_inqueue);
 494
 495         priv->tty_state = TTY_CLOSED;
 496         priv->iucv_state = IUCV_DISCONN;
 497
 498         priv->sndbuf_len = 0;
 499 }
 500
 501 /**
 502  * tty_outqueue_empty() - Test if the tty outq is empty
 503  * @priv:       Pointer to struct hvc_iucv_private instance.
 504  */
 505 static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 506 {
 507         int rc;
 508
 509         spin_lock_bh(&priv->lock);
 510         rc = list_empty(&priv->tty_outqueue);
 511         spin_unlock_bh(&priv->lock);
 512
 513         return rc;
 514 }
 515
 516 /**
 517  * flush_sndbuf_sync() - Flush send buffer and wait for completion
 518  * @priv:       Pointer to struct hvc_iucv_private instance.
 519  *
 520  * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 521  * to flush any buffered terminal output data and waits for completion.
 522  */
 523 static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 524 {
 525         int sync_wait;
 526
 527         cancel_delayed_work_sync(&priv->sndbuf_work);
 528
 529         spin_lock_bh(&priv->lock);
 530         hvc_iucv_send(priv);            /* force sending buffered data */
 531         sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 532         spin_unlock_bh(&priv->lock);
 533
 534         if (sync_wait)
 535                 wait_event_timeout(priv->sndbuf_waitq,
 536                                    tty_outqueue_empty(priv), HZ);
 537 }
 538
 539 /**
 540  * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 541  * @hp:         Pointer to the HVC device (struct hvc_struct)
 542  * @id:         Additional data (originally passed to hvc_alloc):
 543  *              the index of an struct hvc_iucv_private instance.
 544  *
 545  * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 546  * virtual or otherwise) has occured.
 547  * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 548  * to keep an existing IUCV communication path established.
 549  * (Background: vhangup() is called from user space (by getty or login) to
 550  *              disable writing to the tty by other applications).
 551  * If the tty has been opened and an established IUCV path has been severed
 552  * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 553  *
 554  * Locking:     struct hvc_iucv_private->lock
 555  */
 556 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 557 {
 558         struct hvc_iucv_private *priv;
 559
 560         priv = hvc_iucv_get_private(id);
 561         if (!priv)
 562                 return;
 563
 564         flush_sndbuf_sync(priv);
 565
 566         spin_lock_bh(&priv->lock);
 567         /* NOTE: If the hangup was scheduled by ourself (from the iucv
 568          *       path_servered callback [IUCV_SEVERED]), we have to clean up
 569          *       our structure and to set state to TTY_CLOSED.
 570          *       If the tty was hung up otherwise (e.g. vhangup()), then we
 571          *       ignore this hangup and keep an established IUCV path open...
 572          *       (...the reason is that we are not able to connect back to the
 573          *       client if we disconnect on hang up) */
 574         priv->tty_state = TTY_CLOSED;
 575
 576         if (priv->iucv_state == IUCV_SEVERED)
 577                 hvc_iucv_cleanup(priv);
 578         spin_unlock_bh(&priv->lock);
 579 }
 580
 581 /**
 582  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 583  * @hp:         Pointer to the HVC device (struct hvc_struct)
 584  * @id:         Additional data (originally passed to hvc_alloc):
 585  *              the index of an struct hvc_iucv_private instance.
 586  *
 587  * This routine notifies the HVC back-end that the last tty device fd has been
 588  * closed.  The function calls hvc_iucv_cleanup() to clean up the struct
 589  * hvc_iucv_private instance.
 590  *
 591  * Locking:     struct hvc_iucv_private->lock
 592  */
 593 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 594 {
 595         struct hvc_iucv_private *priv;
 596         struct iucv_path        *path;
 597
 598         priv = hvc_iucv_get_private(id);
 599         if (!priv)
 600                 return;
 601
 602         flush_sndbuf_sync(priv);
 603
 604         spin_lock_bh(&priv->lock);
 605         path = priv->path;              /* save reference to IUCV path */
 606         priv->path = NULL;
 607         hvc_iucv_cleanup(priv);
 608         spin_unlock_bh(&priv->lock);
 609
 610         /* sever IUCV path outside of priv->lock due to lock ordering of:
 611          * priv->lock <--> iucv_table_lock */
 612         if (path) {
 613                 iucv_path_sever(path, NULL);
 614                 iucv_path_free(path);
 615         }
 616 }
 617
 618 /**
 619  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 620  * @path:       Pending path (struct iucv_path)
 621  * @ipvmid:     z/VM system identifier of originator
 622  * @ipuser:     User specified data for this path
 623  *              (AF_IUCV: port/service name and originator port)
 624  *
 625  * The function uses the @ipuser data to determine if the pending path belongs
 626  * to a terminal managed by this device driver.
 627  * If the path belongs to this driver, ensure that the terminal is not accessed
 628  * multiple times (only one connection to a terminal is allowed).
 629  * If the terminal is not yet connected, the pending path is accepted and is
 630  * associated to the appropriate struct hvc_iucv_private instance.
 631  *
 632  * Returns 0 if @path belongs to a terminal managed by the this device driver;
 633  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 634  *
 635  * Locking:     struct hvc_iucv_private->lock
 636  */
 637 static  int hvc_iucv_path_pending(struct iucv_path *path,
 638                                   u8 ipvmid[8], u8 ipuser[16])
 639 {
 640         struct hvc_iucv_private *priv;
 641         u8 nuser_data[16];
 642         int i, rc;
 643
 644         priv = NULL;
 645         for (i = 0; i < hvc_iucv_devices; i++)
 646                 if (hvc_iucv_table[i] &&
 647                     (0 == memcmp(hvc_iucv_table[i]->srv_name, ipuser, 8))) {
 648                         priv = hvc_iucv_table[i];
 649                         break;
 650                 }
 651         if (!priv)
 652                 return -ENODEV;
 653
 654         spin_lock(&priv->lock);
 655
 656         /* If the terminal is already connected or being severed, then sever
 657          * this path to enforce that there is only ONE established communication
 658          * path per terminal. */
 659         if (priv->iucv_state != IUCV_DISCONN) {
 660                 iucv_path_sever(path, ipuser);
 661                 iucv_path_free(path);
 662                 goto out_path_handled;
 663         }
 664
 665         /* accept path */
 666         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 667         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 668         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 669         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 670         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 671         if (rc) {
 672                 iucv_path_sever(path, ipuser);
 673                 iucv_path_free(path);
 674                 goto out_path_handled;
 675         }
 676         priv->path = path;
 677         priv->iucv_state = IUCV_CONNECTED;
 678
 679         /* flush buffered output data... */
 680         schedule_delayed_work(&priv->sndbuf_work, 5);
 681
 682 out_path_handled:
 683         spin_unlock(&priv->lock);
 684         return 0;
 685 }
 686
 687 /**
 688  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 689  * @path:       Pending path (struct iucv_path)
 690  * @ipuser:     User specified data for this path
 691  *              (AF_IUCV: port/service name and originator port)
 692  *
 693  * The function also severs the path (as required by the IUCV protocol) and
 694  * sets the iucv state to IUCV_SEVERED for the associated struct
 695  * hvc_iucv_private instance. Later, the IUCV_SEVERED state triggers a tty
 696  * hangup (hvc_iucv_get_chars() / hvc_iucv_write()).
 697  * If tty portion of the HVC is closed, clean up the outqueue.
 698  *
 699  * Locking:     struct hvc_iucv_private->lock
 700  */
 701 static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 702 {
 703         struct hvc_iucv_private *priv = path->private;
 704
 705         spin_lock(&priv->lock);
 706         priv->iucv_state = IUCV_SEVERED;
 707
 708         /* If the tty has not yet been opened, clean up the hvc_iucv_private
 709          * structure to allow re-connects.
 710          *
 711          * If it has been opened, let get_chars() return -EPIPE to signal the
 712          * HVC layer to hang up the tty.
 713          * If so, we need to wake up the HVC thread to call get_chars()...
 714          */
 715         priv->path = NULL;
 716         if (priv->tty_state == TTY_CLOSED)
 717                 hvc_iucv_cleanup(priv);
 718         else
 719                 hvc_kick();
 720         spin_unlock(&priv->lock);
 721
 722         /* finally sever path (outside of priv->lock due to lock ordering) */
 723         iucv_path_sever(path, ipuser);
 724         iucv_path_free(path);
 725 }
 726
 727 /**
 728  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 729  * @path:       Pending path (struct iucv_path)
 730  * @msg:        Pointer to the IUCV message
 731  *
 732  * The function puts an incoming message on the input queue for later
 733  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 734  * If the tty has not yet been opened, the message is rejected.
 735  *
 736  * Locking:     struct hvc_iucv_private->lock
 737  */
 738 static void hvc_iucv_msg_pending(struct iucv_path *path,
 739                                  struct iucv_message *msg)
 740 {
 741         struct hvc_iucv_private *priv = path->private;
 742         struct iucv_tty_buffer *rb;
 743
 744         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 745         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 746                 iucv_message_reject(path, msg);
 747                 return;
 748         }
 749
 750
 751         spin_lock(&priv->lock);
 752
 753         /* reject messages if tty has not yet been opened */
 754         if (priv->tty_state == TTY_CLOSED) {
 755                 iucv_message_reject(path, msg);
 756                 goto unlock_return;
 757         }
 758
 759         /* allocate tty buffer to save iucv msg only */
 760         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 761         if (!rb) {
 762                 iucv_message_reject(path, msg);
 763                 goto unlock_return;     /* -ENOMEM */
 764         }
 765         rb->msg = *msg;
 766
 767         list_add_tail(&rb->list, &priv->tty_inqueue);
 768
 769         hvc_kick();     /* wake up hvc thread */
 770
 771 unlock_return:
 772         spin_unlock(&priv->lock);
 773 }
 774
 775 /**
 776  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 777  * @path:       Pending path (struct iucv_path)
 778  * @msg:        Pointer to the IUCV message
 779  *
 780  * The function is called upon completion of message delivery to remove the
 781  * message from the outqueue. Additional delivery information can be found
 782  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 783  *             purged messages   (0x010000 (IPADPGNR)).
 784  *
 785  * Locking:     struct hvc_iucv_private->lock
 786  */
 787 static void hvc_iucv_msg_complete(struct iucv_path *path,
 788                                   struct iucv_message *msg)
 789 {
 790         struct hvc_iucv_private *priv = path->private;
 791         struct iucv_tty_buffer  *ent, *next;
 792         LIST_HEAD(list_remove);
 793
 794         spin_lock(&priv->lock);
 795         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 796                 if (ent->msg.id == msg->id) {
 797                         list_move(&ent->list, &list_remove);
 798                         break;
 799                 }
 800         wake_up(&priv->sndbuf_waitq);
 801         spin_unlock(&priv->lock);
 802         destroy_tty_buffer_list(&list_remove);
 803 }
 804
 805
 806 /* HVC operations */
 807 static struct hv_ops hvc_iucv_ops = {
 808         .get_chars = hvc_iucv_get_chars,
 809         .put_chars = hvc_iucv_put_chars,
 810         .notifier_add = hvc_iucv_notifier_add,
 811         .notifier_del = hvc_iucv_notifier_del,
 812         .notifier_hangup = hvc_iucv_notifier_hangup,
 813 };
 814
 815 /**
 816  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
 817  * @id: hvc_iucv_table index
 818  *
 819  * This function allocates a new hvc_iucv_private structure and stores
 820  * the instance in hvc_iucv_table at index @id.
 821  * Returns 0 on success; otherwise non-zero.
 822  */
 823 static int __init hvc_iucv_alloc(int id)
 824 {
 825         struct hvc_iucv_private *priv;
 826         char name[9];
 827         int rc;
 828
 829         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
 830         if (!priv)
 831                 return -ENOMEM;
 832
 833         spin_lock_init(&priv->lock);
 834         INIT_LIST_HEAD(&priv->tty_outqueue);
 835         INIT_LIST_HEAD(&priv->tty_inqueue);
 836         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
 837         init_waitqueue_head(&priv->sndbuf_waitq);
 838
 839         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
 840         if (!priv->sndbuf) {
 841                 kfree(priv);
 842                 return -ENOMEM;
 843         }
 844
 845         /* finally allocate hvc */
 846         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
 847                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
 848         if (IS_ERR(priv->hvc)) {
 849                 rc = PTR_ERR(priv->hvc);
 850                 free_page((unsigned long) priv->sndbuf);
 851                 kfree(priv);
 852                 return rc;
 853         }
 854
 855         /* notify HVC thread instead of using polling */
 856         priv->hvc->irq_requested = 1;
 857
 858         /* setup iucv related information */
 859         snprintf(name, 9, "lnxhvc%-2d", id);
 860         memcpy(priv->srv_name, name, 8);
 861         ASCEBC(priv->srv_name, 8);
 862
 863         hvc_iucv_table[id] = priv;
 864         return 0;
 865 }
 866
 867 /**
 868  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
 869  */
 870 static int __init hvc_iucv_init(void)
 871 {
 872         int rc, i;
 873
 874         if (!MACHINE_IS_VM) {
 875                 pr_info("The z/VM IUCV HVC device driver cannot "
 876                            "be used without z/VM\n");
 877                 return -ENODEV;
 878         }
 879
 880         if (!hvc_iucv_devices)
 881                 return -ENODEV;
 882
 883         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES)
 884                 return -EINVAL;
 885
 886         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
 887                                            sizeof(struct iucv_tty_buffer),
 888                                            0, 0, NULL);
 889         if (!hvc_iucv_buffer_cache) {
 890                 pr_err("Allocating memory failed with reason code=%d\n", 1);
 891                 return -ENOMEM;
 892         }
 893
 894         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
 895                                                     hvc_iucv_buffer_cache);
 896         if (!hvc_iucv_mempool) {
 897                 pr_err("Allocating memory failed with reason code=%d\n", 2);
 898                 kmem_cache_destroy(hvc_iucv_buffer_cache);
 899                 return -ENOMEM;
 900         }
 901
 902         /* register the first terminal device as console
 903          * (must be done before allocating hvc terminal devices) */
 904         rc = hvc_instantiate(HVC_IUCV_MAGIC, 0, &hvc_iucv_ops);
 905         if (rc)
 906                 pr_warning("Registering HVC terminal device as "
 907                            "Linux console failed\n");
 908
 909         /* allocate hvc_iucv_private structs */
 910         for (i = 0; i < hvc_iucv_devices; i++) {
 911                 rc = hvc_iucv_alloc(i);
 912                 if (rc) {
 913                         pr_err("Creating a new HVC terminal device "
 914                                 "failed with error code=%d\n", rc);
 915                         goto out_error_hvc;
 916                 }
 917         }
 918
 919         /* register IUCV callback handler */
 920         rc = iucv_register(&hvc_iucv_handler, 0);
 921         if (rc) {
 922                 pr_err("Registering IUCV handlers failed with error code=%d\n",
 923                         rc);
 924                 goto out_error_iucv;
 925         }
 926
 927         return 0;
 928
 929 out_error_iucv:
 930         iucv_unregister(&hvc_iucv_handler, 0);
 931 out_error_hvc:
 932         for (i = 0; i < hvc_iucv_devices; i++)
 933                 if (hvc_iucv_table[i]) {
 934                         if (hvc_iucv_table[i]->hvc)
 935                                 hvc_remove(hvc_iucv_table[i]->hvc);
 936                         kfree(hvc_iucv_table[i]);
 937                 }
 938         mempool_destroy(hvc_iucv_mempool);
 939         kmem_cache_destroy(hvc_iucv_buffer_cache);
 940         return rc;
 941 }
 942
 943 /**
 944  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
 945  * @val:        Parameter value (numeric)
 946  */
 947 static  int __init hvc_iucv_config(char *val)
 948 {
 949          return strict_strtoul(val, 10, &hvc_iucv_devices);
 950 }
 951
 952
 953 device_initcall(hvc_iucv_init);
 954 __setup("hvc_iucv=", hvc_iucv_config);