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/mempool.h>
  18 #include <linux/module.h>
  19 #include <linux/tty.h>
  20 #include <linux/wait.h>
  21 #include <net/iucv/iucv.h>
  22
  23 #include "hvc_console.h"
  24
  25
  26 /* General device driver settings */
  27 #define HVC_IUCV_MAGIC          0xc9e4c3e5
  28 #define MAX_HVC_IUCV_LINES      HVC_ALLOC_TTY_ADAPTERS
  29 #define MEMPOOL_MIN_NR          (PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)
  30
  31 /* IUCV TTY message  */
  32 #define MSG_VERSION             0x02    /* Message version */
  33 #define MSG_TYPE_ERROR          0x01    /* Error message */
  34 #define MSG_TYPE_TERMENV        0x02    /* Terminal environment variable */
  35 #define MSG_TYPE_TERMIOS        0x04    /* Terminal IO struct update */
  36 #define MSG_TYPE_WINSIZE        0x08    /* Terminal window size update */
  37 #define MSG_TYPE_DATA           0x10    /* Terminal data */
  38
  39 struct iucv_tty_msg {
  40         u8      version;                /* Message version */
  41         u8      type;                   /* Message type */
  42 #define MSG_MAX_DATALEN         ((u16)(~0))
  43         u16     datalen;                /* Payload length */
  44         u8      data[];                 /* Payload buffer */
  45 } __attribute__((packed));
  46 #define MSG_SIZE(s)             ((s) + offsetof(struct iucv_tty_msg, data))
  47
  48 enum iucv_state_t {
  49         IUCV_DISCONN    = 0,
  50         IUCV_CONNECTED  = 1,
  51         IUCV_SEVERED    = 2,
  52 };
  53
  54 enum tty_state_t {
  55         TTY_CLOSED      = 0,
  56         TTY_OPENED      = 1,
  57 };
  58
  59 struct hvc_iucv_private {
  60         struct hvc_struct       *hvc;           /* HVC struct reference */
  61         u8                      srv_name[8];    /* IUCV service name (ebcdic) */
  62         enum iucv_state_t       iucv_state;     /* IUCV connection status */
  63         enum tty_state_t        tty_state;      /* TTY status */
  64         struct iucv_path        *path;          /* IUCV path pointer */
  65         spinlock_t              lock;           /* hvc_iucv_private lock */
  66 #define SNDBUF_SIZE             (PAGE_SIZE)     /* must be < MSG_MAX_DATALEN */
  67         void                    *sndbuf;        /* send buffer            */
  68         size_t                  sndbuf_len;     /* length of send buffer  */
  69 #define QUEUE_SNDBUF_DELAY      (HZ / 25)
  70         struct delayed_work     sndbuf_work;    /* work: send iucv msg(s) */
  71         wait_queue_head_t       sndbuf_waitq;   /* wait for send completion */
  72         struct list_head        tty_outqueue;   /* outgoing IUCV messages */
  73         struct list_head        tty_inqueue;    /* incoming IUCV messages */
  74 };
  75
  76 struct iucv_tty_buffer {
  77         struct list_head        list;   /* list pointer */
  78         struct iucv_message     msg;    /* store an IUCV message */
  79         size_t                  offset; /* data buffer offset */
  80         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
  81 };
  82
  83 /* IUCV callback handler */
  84 static  int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
  85 static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
  86 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  87 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  88
  89
  90 /* Kernel module parameter: use one terminal device as default */
  91 static unsigned long hvc_iucv_devices = 1;
  92
  93 /* Array of allocated hvc iucv tty lines... */
  94 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
  95
  96 /* Kmem cache and mempool for iucv_tty_buffer elements */
  97 static struct kmem_cache *hvc_iucv_buffer_cache;
  98 static mempool_t *hvc_iucv_mempool;
  99
 100 /* IUCV handler callback functions */
 101 static struct iucv_handler hvc_iucv_handler = {
 102         .path_pending  = hvc_iucv_path_pending,
 103         .path_severed  = hvc_iucv_path_severed,
 104         .message_complete = hvc_iucv_msg_complete,
 105         .message_pending  = hvc_iucv_msg_pending,
 106 };
 107
 108
 109 /**
 110  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
 111  * @num:        The HVC virtual terminal number (vtermno)
 112  *
 113  * This function returns the struct hvc_iucv_private instance that corresponds
 114  * to the HVC virtual terminal number specified as parameter @num.
 115  */
 116 struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
 117 {
 118         if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
 119                 return NULL;
 120         return hvc_iucv_table[num - HVC_IUCV_MAGIC];
 121 }
 122
 123 /**
 124  * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
 125  * @size:       Size of the internal buffer used to store data.
 126  * @flags:      Memory allocation flags passed to mempool.
 127  *
 128  * This function allocates a new struct iucv_tty_buffer element and, optionally,
 129  * allocates an internal data buffer with the specified size @size.
 130  * Note: The total message size arises from the internal buffer size and the
 131  *       members of the iucv_tty_msg structure.
 132  * The function returns NULL if memory allocation has failed.
 133  */
 134 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
 135 {
 136         struct iucv_tty_buffer *bufp;
 137
 138         bufp = mempool_alloc(hvc_iucv_mempool, flags);
 139         if (!bufp)
 140                 return NULL;
 141         memset(bufp, 0, sizeof(struct iucv_tty_buffer));
 142
 143         if (size > 0) {
 144                 bufp->msg.length = MSG_SIZE(size);
 145                 bufp->mbuf = kmalloc(bufp->msg.length, flags);
 146                 if (!bufp->mbuf) {
 147                         mempool_free(bufp, hvc_iucv_mempool);
 148                         return NULL;
 149                 }
 150                 bufp->mbuf->version = MSG_VERSION;
 151                 bufp->mbuf->type    = MSG_TYPE_DATA;
 152                 bufp->mbuf->datalen = (u16) size;
 153         }
 154         return bufp;
 155 }
 156
 157 /**
 158  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
 159  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
 160  */
 161 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
 162 {
 163         kfree(bufp->mbuf);
 164         mempool_free(bufp, hvc_iucv_mempool);
 165 }
 166
 167 /**
 168  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
 169  * @list:       List containing struct iucv_tty_buffer elements.
 170  */
 171 static void destroy_tty_buffer_list(struct list_head *list)
 172 {
 173         struct iucv_tty_buffer *ent, *next;
 174
 175         list_for_each_entry_safe(ent, next, list, list) {
 176                 list_del(&ent->list);
 177                 destroy_tty_buffer(ent);
 178         }
 179 }
 180
 181 /**
 182  * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
 183  * @priv:               Pointer to struct hvc_iucv_private
 184  * @buf:                HVC buffer for writing received terminal data.
 185  * @count:              HVC buffer size.
 186  * @has_more_data:      Pointer to an int variable.
 187  *
 188  * The function picks up pending messages from the input queue and receives
 189  * the message data that is then written to the specified buffer @buf.
 190  * If the buffer size @count is less than the data message size, the
 191  * message is kept on the input queue and @has_more_data is set to 1.
 192  * If all message data has been written, the message is removed from
 193  * the input queue.
 194  *
 195  * The function returns the number of bytes written to the terminal, zero if
 196  * there are no pending data messages available or if there is no established
 197  * IUCV path.
 198  * If the IUCV path has been severed, then -EPIPE is returned to cause a
 199  * hang up (that is issued by the HVC layer).
 200  */
 201 static int hvc_iucv_write(struct hvc_iucv_private *priv,
 202                           char *buf, int count, int *has_more_data)
 203 {
 204         struct iucv_tty_buffer *rb;
 205         int written;
 206         int rc;
 207
 208         /* immediately return if there is no IUCV connection */
 209         if (priv->iucv_state == IUCV_DISCONN)
 210                 return 0;
 211
 212         /* if the IUCV path has been severed, return -EPIPE to inform the
 213          * HVC layer to hang up the tty device. */
 214         if (priv->iucv_state == IUCV_SEVERED)
 215                 return -EPIPE;
 216
 217         /* check if there are pending messages */
 218         if (list_empty(&priv->tty_inqueue))
 219                 return 0;
 220
 221         /* receive an iucv message and flip data to the tty (ldisc) */
 222         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
 223
 224         written = 0;
 225         if (!rb->mbuf) { /* message not yet received ... */
 226                 /* allocate mem to store msg data; if no memory is available
 227                  * then leave the buffer on the list and re-try later */
 228                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC);
 229                 if (!rb->mbuf)
 230                         return -ENOMEM;
 231
 232                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
 233                                             rb->mbuf, rb->msg.length, NULL);
 234                 switch (rc) {
 235                 case 0: /* Successful       */
 236                         break;
 237                 case 2: /* No message found */
 238                 case 9: /* Message purged   */
 239                         break;
 240                 default:
 241                         written = -EIO;
 242                 }
 243                 /* remove buffer if an error has occured or received data
 244                  * is not correct */
 245                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
 246                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
 247                         goto out_remove_buffer;
 248         }
 249
 250         switch (rb->mbuf->type) {
 251         case MSG_TYPE_DATA:
 252                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
 253                 memcpy(buf, rb->mbuf->data + rb->offset, written);
 254                 if (written < (rb->mbuf->datalen - rb->offset)) {
 255                         rb->offset += written;
 256                         *has_more_data = 1;
 257                         goto out_written;
 258                 }
 259                 break;
 260
 261         case MSG_TYPE_WINSIZE:
 262                 if (rb->mbuf->datalen != sizeof(struct winsize))
 263                         break;
 264                 hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
 265                 break;
 266
 267         case MSG_TYPE_ERROR:    /* ignored ... */
 268         case MSG_TYPE_TERMENV:  /* ignored ... */
 269         case MSG_TYPE_TERMIOS:  /* ignored ... */
 270                 break;
 271         }
 272
 273 out_remove_buffer:
 274         list_del(&rb->list);
 275         destroy_tty_buffer(rb);
 276         *has_more_data = !list_empty(&priv->tty_inqueue);
 277
 278 out_written:
 279         return written;
 280 }
 281
 282 /**
 283  * hvc_iucv_get_chars() - HVC get_chars operation.
 284  * @vtermno:    HVC virtual terminal number.
 285  * @buf:        Pointer to a buffer to store data
 286  * @count:      Size of buffer available for writing
 287  *
 288  * The HVC thread calls this method to read characters from the back-end.
 289  * If an IUCV communication path has been established, pending IUCV messages
 290  * are received and data is copied into buffer @buf up to @count bytes.
 291  *
 292  * Locking:     The routine gets called under an irqsave() spinlock; and
 293  *              the routine locks the struct hvc_iucv_private->lock to call
 294  *              helper functions.
 295  */
 296 static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
 297 {
 298         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 299         int written;
 300         int has_more_data;
 301
 302         if (count <= 0)
 303                 return 0;
 304
 305         if (!priv)
 306                 return -ENODEV;
 307
 308         spin_lock(&priv->lock);
 309         has_more_data = 0;
 310         written = hvc_iucv_write(priv, buf, count, &has_more_data);
 311         spin_unlock(&priv->lock);
 312
 313         /* if there are still messages on the queue... schedule another run */
 314         if (has_more_data)
 315                 hvc_kick();
 316
 317         return written;
 318 }
 319
 320 /**
 321  * hvc_iucv_queue() - Buffer terminal data for sending.
 322  * @priv:       Pointer to struct hvc_iucv_private instance.
 323  * @buf:        Buffer containing data to send.
 324  * @count:      Size of buffer and amount of data to send.
 325  *
 326  * The function queues data for sending. To actually send the buffered data,
 327  * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
 328  * The function returns the number of data bytes that has been buffered.
 329  *
 330  * If the device is not connected, data is ignored and the function returns
 331  * @count.
 332  * If the buffer is full, the function returns 0.
 333  * If an existing IUCV communicaton path has been severed, -EPIPE is returned
 334  * (that can be passed to HVC layer to cause a tty hangup).
 335  */
 336 static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
 337                           int count)
 338 {
 339         size_t len;
 340
 341         if (priv->iucv_state == IUCV_DISCONN)
 342                 return count;                   /* ignore data */
 343
 344         if (priv->iucv_state == IUCV_SEVERED)
 345                 return -EPIPE;
 346
 347         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
 348         if (!len)
 349                 return 0;
 350
 351         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
 352         priv->sndbuf_len += len;
 353
 354         if (priv->iucv_state == IUCV_CONNECTED)
 355                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
 356
 357         return len;
 358 }
 359
 360 /**
 361  * hvc_iucv_send() - Send an IUCV message containing terminal data.
 362  * @priv:       Pointer to struct hvc_iucv_private instance.
 363  *
 364  * If an IUCV communication path has been established, the buffered output data
 365  * is sent via an IUCV message and the number of bytes sent is returned.
 366  * Returns 0 if there is no established IUCV communication path or
 367  * -EPIPE if an existing IUCV communicaton path has been severed.
 368  */
 369 static int hvc_iucv_send(struct hvc_iucv_private *priv)
 370 {
 371         struct iucv_tty_buffer *sb;
 372         int rc, len;
 373
 374         if (priv->iucv_state == IUCV_SEVERED)
 375                 return -EPIPE;
 376
 377         if (priv->iucv_state == IUCV_DISCONN)
 378                 return -EIO;
 379
 380         if (!priv->sndbuf_len)
 381                 return 0;
 382
 383         /* allocate internal buffer to store msg data and also compute total
 384          * message length */
 385         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
 386         if (!sb)
 387                 return -ENOMEM;
 388
 389         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
 390         sb->mbuf->datalen = (u16) priv->sndbuf_len;
 391         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
 392
 393         list_add_tail(&sb->list, &priv->tty_outqueue);
 394
 395         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
 396                                  (void *) sb->mbuf, sb->msg.length);
 397         if (rc) {
 398                 /* drop the message here; however we might want to handle
 399                  * 0x03 (msg limit reached) by trying again... */
 400                 list_del(&sb->list);
 401                 destroy_tty_buffer(sb);
 402         }
 403         len = priv->sndbuf_len;
 404         priv->sndbuf_len = 0;
 405
 406         return len;
 407 }
 408
 409 /**
 410  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
 411  * @work:       Work structure.
 412  *
 413  * This work queue function sends buffered output data over IUCV and,
 414  * if not all buffered data could be sent, reschedules itself.
 415  */
 416 static void hvc_iucv_sndbuf_work(struct work_struct *work)
 417 {
 418         struct hvc_iucv_private *priv;
 419
 420         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 421         if (!priv)
 422                 return;
 423
 424         spin_lock_bh(&priv->lock);
 425         hvc_iucv_send(priv);
 426         spin_unlock_bh(&priv->lock);
 427 }
 428
 429 /**
 430  * hvc_iucv_put_chars() - HVC put_chars operation.
 431  * @vtermno:    HVC virtual terminal number.
 432  * @buf:        Pointer to an buffer to read data from
 433  * @count:      Size of buffer available for reading
 434  *
 435  * The HVC thread calls this method to write characters to the back-end.
 436  * The function calls hvc_iucv_queue() to queue terminal data for sending.
 437  *
 438  * Locking:     The method gets called under an irqsave() spinlock; and
 439  *              locks struct hvc_iucv_private->lock.
 440  */
 441 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 442 {
 443         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 444         int queued;
 445
 446         if (count <= 0)
 447                 return 0;
 448
 449         if (!priv)
 450                 return -ENODEV;
 451
 452         spin_lock(&priv->lock);
 453         queued = hvc_iucv_queue(priv, buf, count);
 454         spin_unlock(&priv->lock);
 455
 456         return queued;
 457 }
 458
 459 /**
 460  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 461  * @hp: Pointer to the HVC device (struct hvc_struct)
 462  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 463  *      hvc_iucv_private instance.
 464  *
 465  * The function sets the tty state to TTY_OPEN for the struct hvc_iucv_private
 466  * instance that is derived from @id. Always returns 0.
 467  *
 468  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
 469  */
 470 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 471 {
 472         struct hvc_iucv_private *priv;
 473
 474         priv = hvc_iucv_get_private(id);
 475         if (!priv)
 476                 return 0;
 477
 478         spin_lock_bh(&priv->lock);
 479         priv->tty_state = TTY_OPENED;
 480         spin_unlock_bh(&priv->lock);
 481
 482         return 0;
 483 }
 484
 485 /**
 486  * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 487  * @priv:       Pointer to the struct hvc_iucv_private instance.
 488  */
 489 static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 490 {
 491         destroy_tty_buffer_list(&priv->tty_outqueue);
 492         destroy_tty_buffer_list(&priv->tty_inqueue);
 493
 494         priv->tty_state = TTY_CLOSED;
 495         priv->iucv_state = IUCV_DISCONN;
 496
 497         priv->sndbuf_len = 0;
 498 }
 499
 500 /**
 501  * tty_outqueue_empty() - Test if the tty outq is empty
 502  * @priv:       Pointer to struct hvc_iucv_private instance.
 503  */
 504 static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 505 {
 506         int rc;
 507
 508         spin_lock_bh(&priv->lock);
 509         rc = list_empty(&priv->tty_outqueue);
 510         spin_unlock_bh(&priv->lock);
 511
 512         return rc;
 513 }
 514
 515 /**
 516  * flush_sndbuf_sync() - Flush send buffer and wait for completion
 517  * @priv:       Pointer to struct hvc_iucv_private instance.
 518  *
 519  * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 520  * to flush any buffered terminal output data and waits for completion.
 521  */
 522 static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 523 {
 524         int sync_wait;
 525
 526         cancel_delayed_work_sync(&priv->sndbuf_work);
 527
 528         spin_lock_bh(&priv->lock);
 529         hvc_iucv_send(priv);            /* force sending buffered data */
 530         sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 531         spin_unlock_bh(&priv->lock);
 532
 533         if (sync_wait)
 534                 wait_event_timeout(priv->sndbuf_waitq,
 535                                    tty_outqueue_empty(priv), HZ);
 536 }
 537
 538 /**
 539  * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 540  * @hp:         Pointer to the HVC device (struct hvc_struct)
 541  * @id:         Additional data (originally passed to hvc_alloc):
 542  *              the index of an struct hvc_iucv_private instance.
 543  *
 544  * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 545  * virtual or otherwise) has occured.
 546  * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 547  * to keep an existing IUCV communication path established.
 548  * (Background: vhangup() is called from user space (by getty or login) to
 549  *              disable writing to the tty by other applications).
 550  * If the tty has been opened and an established IUCV path has been severed
 551  * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 552  *
 553  * Locking:     struct hvc_iucv_private->lock
 554  */
 555 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 556 {
 557         struct hvc_iucv_private *priv;
 558
 559         priv = hvc_iucv_get_private(id);
 560         if (!priv)
 561                 return;
 562
 563         flush_sndbuf_sync(priv);
 564
 565         spin_lock_bh(&priv->lock);
 566         /* NOTE: If the hangup was scheduled by ourself (from the iucv
 567          *       path_servered callback [IUCV_SEVERED]), we have to clean up
 568          *       our structure and to set state to TTY_CLOSED.
 569          *       If the tty was hung up otherwise (e.g. vhangup()), then we
 570          *       ignore this hangup and keep an established IUCV path open...
 571          *       (...the reason is that we are not able to connect back to the
 572          *       client if we disconnect on hang up) */
 573         priv->tty_state = TTY_CLOSED;
 574
 575         if (priv->iucv_state == IUCV_SEVERED)
 576                 hvc_iucv_cleanup(priv);
 577         spin_unlock_bh(&priv->lock);
 578 }
 579
 580 /**
 581  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 582  * @hp:         Pointer to the HVC device (struct hvc_struct)
 583  * @id:         Additional data (originally passed to hvc_alloc):
 584  *              the index of an struct hvc_iucv_private instance.
 585  *
 586  * This routine notifies the HVC back-end that the last tty device fd has been
 587  * closed.  The function calls hvc_iucv_cleanup() to clean up the struct
 588  * hvc_iucv_private instance.
 589  *
 590  * Locking:     struct hvc_iucv_private->lock
 591  */
 592 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 593 {
 594         struct hvc_iucv_private *priv;
 595         struct iucv_path        *path;
 596
 597         priv = hvc_iucv_get_private(id);
 598         if (!priv)
 599                 return;
 600
 601         flush_sndbuf_sync(priv);
 602
 603         spin_lock_bh(&priv->lock);
 604         path = priv->path;              /* save reference to IUCV path */
 605         priv->path = NULL;
 606         hvc_iucv_cleanup(priv);
 607         spin_unlock_bh(&priv->lock);
 608
 609         /* sever IUCV path outside of priv->lock due to lock ordering of:
 610          * priv->lock <--> iucv_table_lock */
 611         if (path) {
 612                 iucv_path_sever(path, NULL);
 613                 iucv_path_free(path);
 614         }
 615 }
 616
 617 /**
 618  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 619  * @path:       Pending path (struct iucv_path)
 620  * @ipvmid:     z/VM system identifier of originator
 621  * @ipuser:     User specified data for this path
 622  *              (AF_IUCV: port/service name and originator port)
 623  *
 624  * The function uses the @ipuser data to determine if the pending path belongs
 625  * to a terminal managed by this device driver.
 626  * If the path belongs to this driver, ensure that the terminal is not accessed
 627  * multiple times (only one connection to a terminal is allowed).
 628  * If the terminal is not yet connected, the pending path is accepted and is
 629  * associated to the appropriate struct hvc_iucv_private instance.
 630  *
 631  * Returns 0 if @path belongs to a terminal managed by the this device driver;
 632  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 633  *
 634  * Locking:     struct hvc_iucv_private->lock
 635  */
 636 static  int hvc_iucv_path_pending(struct iucv_path *path,
 637                                   u8 ipvmid[8], u8 ipuser[16])
 638 {
 639         struct hvc_iucv_private *priv;
 640         u8 nuser_data[16];
 641         int i, rc;
 642
 643         priv = NULL;
 644         for (i = 0; i < hvc_iucv_devices; i++)
 645                 if (hvc_iucv_table[i] &&
 646                     (0 == memcmp(hvc_iucv_table[i]->srv_name, ipuser, 8))) {
 647                         priv = hvc_iucv_table[i];
 648                         break;
 649                 }
 650         if (!priv)
 651                 return -ENODEV;
 652
 653         spin_lock(&priv->lock);
 654
 655         /* If the terminal is already connected or being severed, then sever
 656          * this path to enforce that there is only ONE established communication
 657          * path per terminal. */
 658         if (priv->iucv_state != IUCV_DISCONN) {
 659                 iucv_path_sever(path, ipuser);
 660                 iucv_path_free(path);
 661                 goto out_path_handled;
 662         }
 663
 664         /* accept path */
 665         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 666         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 667         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 668         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 669         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 670         if (rc) {
 671                 iucv_path_sever(path, ipuser);
 672                 iucv_path_free(path);
 673                 goto out_path_handled;
 674         }
 675         priv->path = path;
 676         priv->iucv_state = IUCV_CONNECTED;
 677
 678         /* flush buffered output data... */
 679         schedule_delayed_work(&priv->sndbuf_work, 5);
 680
 681 out_path_handled:
 682         spin_unlock(&priv->lock);
 683         return 0;
 684 }
 685
 686 /**
 687  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 688  * @path:       Pending path (struct iucv_path)
 689  * @ipuser:     User specified data for this path
 690  *              (AF_IUCV: port/service name and originator port)
 691  *
 692  * The function also severs the path (as required by the IUCV protocol) and
 693  * sets the iucv state to IUCV_SEVERED for the associated struct
 694  * hvc_iucv_private instance. Later, the IUCV_SEVERED state triggers a tty
 695  * hangup (hvc_iucv_get_chars() / hvc_iucv_write()).
 696  * If tty portion of the HVC is closed, clean up the outqueue.
 697  *
 698  * Locking:     struct hvc_iucv_private->lock
 699  */
 700 static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 701 {
 702         struct hvc_iucv_private *priv = path->private;
 703
 704         spin_lock(&priv->lock);
 705         priv->iucv_state = IUCV_SEVERED;
 706
 707         /* If the tty has not yet been opened, clean up the hvc_iucv_private
 708          * structure to allow re-connects.
 709          *
 710          * If it has been opened, let get_chars() return -EPIPE to signal the
 711          * HVC layer to hang up the tty.
 712          * If so, we need to wake up the HVC thread to call get_chars()...
 713          */
 714         priv->path = NULL;
 715         if (priv->tty_state == TTY_CLOSED)
 716                 hvc_iucv_cleanup(priv);
 717         else
 718                 hvc_kick();
 719         spin_unlock(&priv->lock);
 720
 721         /* finally sever path (outside of priv->lock due to lock ordering) */
 722         iucv_path_sever(path, ipuser);
 723         iucv_path_free(path);
 724 }
 725
 726 /**
 727  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 728  * @path:       Pending path (struct iucv_path)
 729  * @msg:        Pointer to the IUCV message
 730  *
 731  * The function puts an incoming message on the input queue for later
 732  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 733  * If the tty has not yet been opened, the message is rejected.
 734  *
 735  * Locking:     struct hvc_iucv_private->lock
 736  */
 737 static void hvc_iucv_msg_pending(struct iucv_path *path,
 738                                  struct iucv_message *msg)
 739 {
 740         struct hvc_iucv_private *priv = path->private;
 741         struct iucv_tty_buffer *rb;
 742
 743         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 744         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 745                 iucv_message_reject(path, msg);
 746                 return;
 747         }
 748
 749
 750         spin_lock(&priv->lock);
 751
 752         /* reject messages if tty has not yet been opened */
 753         if (priv->tty_state == TTY_CLOSED) {
 754                 iucv_message_reject(path, msg);
 755                 goto unlock_return;
 756         }
 757
 758         /* allocate tty buffer to save iucv msg only */
 759         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 760         if (!rb) {
 761                 iucv_message_reject(path, msg);
 762                 goto unlock_return;     /* -ENOMEM */
 763         }
 764         rb->msg = *msg;
 765
 766         list_add_tail(&rb->list, &priv->tty_inqueue);
 767
 768         hvc_kick();     /* wake up hvc thread */
 769
 770 unlock_return:
 771         spin_unlock(&priv->lock);
 772 }
 773
 774 /**
 775  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 776  * @path:       Pending path (struct iucv_path)
 777  * @msg:        Pointer to the IUCV message
 778  *
 779  * The function is called upon completion of message delivery to remove the
 780  * message from the outqueue. Additional delivery information can be found
 781  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 782  *             purged messages   (0x010000 (IPADPGNR)).
 783  *
 784  * Locking:     struct hvc_iucv_private->lock
 785  */
 786 static void hvc_iucv_msg_complete(struct iucv_path *path,
 787                                   struct iucv_message *msg)
 788 {
 789         struct hvc_iucv_private *priv = path->private;
 790         struct iucv_tty_buffer  *ent, *next;
 791         LIST_HEAD(list_remove);
 792
 793         spin_lock(&priv->lock);
 794         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 795                 if (ent->msg.id == msg->id) {
 796                         list_move(&ent->list, &list_remove);
 797                         break;
 798                 }
 799         wake_up(&priv->sndbuf_waitq);
 800         spin_unlock(&priv->lock);
 801         destroy_tty_buffer_list(&list_remove);
 802 }
 803
 804
 805 /* HVC operations */
 806 static struct hv_ops hvc_iucv_ops = {
 807         .get_chars = hvc_iucv_get_chars,
 808         .put_chars = hvc_iucv_put_chars,
 809         .notifier_add = hvc_iucv_notifier_add,
 810         .notifier_del = hvc_iucv_notifier_del,
 811         .notifier_hangup = hvc_iucv_notifier_hangup,
 812 };
 813
 814 /**
 815  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
 816  * @id: hvc_iucv_table index
 817  *
 818  * This function allocates a new hvc_iucv_private structure and stores
 819  * the instance in hvc_iucv_table at index @id.
 820  * Returns 0 on success; otherwise non-zero.
 821  */
 822 static int __init hvc_iucv_alloc(int id)
 823 {
 824         struct hvc_iucv_private *priv;
 825         char name[9];
 826         int rc;
 827
 828         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
 829         if (!priv)
 830                 return -ENOMEM;
 831
 832         spin_lock_init(&priv->lock);
 833         INIT_LIST_HEAD(&priv->tty_outqueue);
 834         INIT_LIST_HEAD(&priv->tty_inqueue);
 835         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
 836         init_waitqueue_head(&priv->sndbuf_waitq);
 837
 838         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
 839         if (!priv->sndbuf) {
 840                 kfree(priv);
 841                 return -ENOMEM;
 842         }
 843
 844         /* finally allocate hvc */
 845         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
 846                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
 847         if (IS_ERR(priv->hvc)) {
 848                 rc = PTR_ERR(priv->hvc);
 849                 free_page((unsigned long) priv->sndbuf);
 850                 kfree(priv);
 851                 return rc;
 852         }
 853
 854         /* notify HVC thread instead of using polling */
 855         priv->hvc->irq_requested = 1;
 856
 857         /* setup iucv related information */
 858         snprintf(name, 9, "lnxhvc%-2d", id);
 859         memcpy(priv->srv_name, name, 8);
 860         ASCEBC(priv->srv_name, 8);
 861
 862         hvc_iucv_table[id] = priv;
 863         return 0;
 864 }
 865
 866 /**
 867  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
 868  */
 869 static int __init hvc_iucv_init(void)
 870 {
 871         int rc, i;
 872
 873         if (!MACHINE_IS_VM) {
 874                 pr_info("The z/VM IUCV HVC device driver cannot "
 875                            "be used without z/VM\n");
 876                 return -ENODEV;
 877         }
 878
 879         if (!hvc_iucv_devices)
 880                 return -ENODEV;
 881
 882         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES)
 883                 return -EINVAL;
 884
 885         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
 886                                            sizeof(struct iucv_tty_buffer),
 887                                            0, 0, NULL);
 888         if (!hvc_iucv_buffer_cache) {
 889                 pr_err("Allocating memory failed with reason code=%d\n", 1);
 890                 return -ENOMEM;
 891         }
 892
 893         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
 894                                                     hvc_iucv_buffer_cache);
 895         if (!hvc_iucv_mempool) {
 896                 pr_err("Allocating memory failed with reason code=%d\n", 2);
 897                 kmem_cache_destroy(hvc_iucv_buffer_cache);
 898                 return -ENOMEM;
 899         }
 900
 901         /* allocate hvc_iucv_private structs */
 902         for (i = 0; i < hvc_iucv_devices; i++) {
 903                 rc = hvc_iucv_alloc(i);
 904                 if (rc) {
 905                         pr_err("Creating a new HVC terminal device "
 906                                 "failed with error code=%d\n", rc);
 907                         goto out_error_hvc;
 908                 }
 909         }
 910
 911         /* register IUCV callback handler */
 912         rc = iucv_register(&hvc_iucv_handler, 0);
 913         if (rc) {
 914                 pr_err("Registering IUCV handlers failed with error code=%d\n",
 915                         rc);
 916                 goto out_error_iucv;
 917         }
 918
 919         return 0;
 920
 921 out_error_iucv:
 922         iucv_unregister(&hvc_iucv_handler, 0);
 923 out_error_hvc:
 924         for (i = 0; i < hvc_iucv_devices; i++)
 925                 if (hvc_iucv_table[i]) {
 926                         if (hvc_iucv_table[i]->hvc)
 927                                 hvc_remove(hvc_iucv_table[i]->hvc);
 928                         kfree(hvc_iucv_table[i]);
 929                 }
 930         mempool_destroy(hvc_iucv_mempool);
 931         kmem_cache_destroy(hvc_iucv_buffer_cache);
 932         return rc;
 933 }
 934
 935 /**
 936  * hvc_iucv_console_init() - Early console initialization
 937  */
 938 static  int __init hvc_iucv_console_init(void)
 939 {
 940         if (!MACHINE_IS_VM || !hvc_iucv_devices)
 941                 return -ENODEV;
 942         return hvc_instantiate(HVC_IUCV_MAGIC, 0, &hvc_iucv_ops);
 943 }
 944
 945 /**
 946  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
 947  * @val:        Parameter value (numeric)
 948  */
 949 static  int __init hvc_iucv_config(char *val)
 950 {
 951          return strict_strtoul(val, 10, &hvc_iucv_devices);
 952 }
 953
 954
 955 module_init(hvc_iucv_init);
 956 console_initcall(hvc_iucv_console_init);
 957 __setup("hvc_iucv=", hvc_iucv_config);
 958
 959 MODULE_LICENSE("GPL");
 960 MODULE_DESCRIPTION("HVC back-end for z/VM IUCV.");
 961 MODULE_AUTHOR("Hendrik Brueckner <brueckner@linux.vnet.ibm.com>");