git.oblomov.eu Git - linux-2.6/blob - 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         unsigned char           is_console;     /* Linux console usage flag */
  64         enum iucv_state_t       iucv_state;     /* IUCV connection status */
  65         enum tty_state_t        tty_state;      /* TTY status */
  66         struct iucv_path        *path;          /* IUCV path pointer */
  67         spinlock_t              lock;           /* hvc_iucv_private lock */
  68 #define SNDBUF_SIZE             (PAGE_SIZE)     /* must be < MSG_MAX_DATALEN */
  69         void                    *sndbuf;        /* send buffer            */
  70         size_t                  sndbuf_len;     /* length of send buffer  */
  71 #define QUEUE_SNDBUF_DELAY      (HZ / 25)
  72         struct delayed_work     sndbuf_work;    /* work: send iucv msg(s) */
  73         wait_queue_head_t       sndbuf_waitq;   /* wait for send completion */
  74         struct list_head        tty_outqueue;   /* outgoing IUCV messages */
  75         struct list_head        tty_inqueue;    /* incoming IUCV messages */
  76 };
  77
  78 struct iucv_tty_buffer {
  79         struct list_head        list;   /* list pointer */
  80         struct iucv_message     msg;    /* store an IUCV message */
  81         size_t                  offset; /* data buffer offset */
  82         struct iucv_tty_msg     *mbuf;  /* buffer to store input/output data */
  83 };
  84
  85 /* IUCV callback handler */
  86 static  int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
  87 static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
  88 static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
  89 static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);
  90
  91
  92 /* Kernel module parameter: use one terminal device as default */
  93 static unsigned long hvc_iucv_devices = 1;
  94
  95 /* Array of allocated hvc iucv tty lines... */
  96 static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
  97 #define IUCV_HVC_CON_IDX        (0)
  98
  99 /* Kmem cache and mempool for iucv_tty_buffer elements */
 100 static struct kmem_cache *hvc_iucv_buffer_cache;
 101 static mempool_t *hvc_iucv_mempool;
 102
 103 /* IUCV handler callback functions */
 104 static struct iucv_handler hvc_iucv_handler = {
 105         .path_pending  = hvc_iucv_path_pending,
 106         .path_severed  = hvc_iucv_path_severed,
 107         .message_complete = hvc_iucv_msg_complete,
 108         .message_pending  = hvc_iucv_msg_pending,
 109 };
 110
 111
 112 /**
 113  * hvc_iucv_get_private() - Return a struct hvc_iucv_private instance.
 114  * @num:        The HVC virtual terminal number (vtermno)
 115  *
 116  * This function returns the struct hvc_iucv_private instance that corresponds
 117  * to the HVC virtual terminal number specified as parameter @num.
 118  */
 119 struct hvc_iucv_private *hvc_iucv_get_private(uint32_t num)
 120 {
 121         if ((num < HVC_IUCV_MAGIC) || (num - HVC_IUCV_MAGIC > hvc_iucv_devices))
 122                 return NULL;
 123         return hvc_iucv_table[num - HVC_IUCV_MAGIC];
 124 }
 125
 126 /**
 127  * alloc_tty_buffer() - Return a new struct iucv_tty_buffer element.
 128  * @size:       Size of the internal buffer used to store data.
 129  * @flags:      Memory allocation flags passed to mempool.
 130  *
 131  * This function allocates a new struct iucv_tty_buffer element and, optionally,
 132  * allocates an internal data buffer with the specified size @size.
 133  * Note: The total message size arises from the internal buffer size and the
 134  *       members of the iucv_tty_msg structure.
 135  * The function returns NULL if memory allocation has failed.
 136  */
 137 static struct iucv_tty_buffer *alloc_tty_buffer(size_t size, gfp_t flags)
 138 {
 139         struct iucv_tty_buffer *bufp;
 140
 141         bufp = mempool_alloc(hvc_iucv_mempool, flags);
 142         if (!bufp)
 143                 return NULL;
 144         memset(bufp, 0, sizeof(*bufp));
 145
 146         if (size > 0) {
 147                 bufp->msg.length = MSG_SIZE(size);
 148                 bufp->mbuf = kmalloc(bufp->msg.length, flags);
 149                 if (!bufp->mbuf) {
 150                         mempool_free(bufp, hvc_iucv_mempool);
 151                         return NULL;
 152                 }
 153                 bufp->mbuf->version = MSG_VERSION;
 154                 bufp->mbuf->type    = MSG_TYPE_DATA;
 155                 bufp->mbuf->datalen = (u16) size;
 156         }
 157         return bufp;
 158 }
 159
 160 /**
 161  * destroy_tty_buffer() - destroy struct iucv_tty_buffer element.
 162  * @bufp:       Pointer to a struct iucv_tty_buffer element, SHALL NOT be NULL.
 163  */
 164 static void destroy_tty_buffer(struct iucv_tty_buffer *bufp)
 165 {
 166         kfree(bufp->mbuf);
 167         mempool_free(bufp, hvc_iucv_mempool);
 168 }
 169
 170 /**
 171  * destroy_tty_buffer_list() - call destroy_tty_buffer() for each list element.
 172  * @list:       List containing struct iucv_tty_buffer elements.
 173  */
 174 static void destroy_tty_buffer_list(struct list_head *list)
 175 {
 176         struct iucv_tty_buffer *ent, *next;
 177
 178         list_for_each_entry_safe(ent, next, list, list) {
 179                 list_del(&ent->list);
 180                 destroy_tty_buffer(ent);
 181         }
 182 }
 183
 184 /**
 185  * hvc_iucv_write() - Receive IUCV message & write data to HVC buffer.
 186  * @priv:               Pointer to struct hvc_iucv_private
 187  * @buf:                HVC buffer for writing received terminal data.
 188  * @count:              HVC buffer size.
 189  * @has_more_data:      Pointer to an int variable.
 190  *
 191  * The function picks up pending messages from the input queue and receives
 192  * the message data that is then written to the specified buffer @buf.
 193  * If the buffer size @count is less than the data message size, the
 194  * message is kept on the input queue and @has_more_data is set to 1.
 195  * If all message data has been written, the message is removed from
 196  * the input queue.
 197  *
 198  * The function returns the number of bytes written to the terminal, zero if
 199  * there are no pending data messages available or if there is no established
 200  * IUCV path.
 201  * If the IUCV path has been severed, then -EPIPE is returned to cause a
 202  * hang up (that is issued by the HVC layer).
 203  */
 204 static int hvc_iucv_write(struct hvc_iucv_private *priv,
 205                           char *buf, int count, int *has_more_data)
 206 {
 207         struct iucv_tty_buffer *rb;
 208         int written;
 209         int rc;
 210
 211         /* immediately return if there is no IUCV connection */
 212         if (priv->iucv_state == IUCV_DISCONN)
 213                 return 0;
 214
 215         /* if the IUCV path has been severed, return -EPIPE to inform the
 216          * HVC layer to hang up the tty device. */
 217         if (priv->iucv_state == IUCV_SEVERED)
 218                 return -EPIPE;
 219
 220         /* check if there are pending messages */
 221         if (list_empty(&priv->tty_inqueue))
 222                 return 0;
 223
 224         /* receive an iucv message and flip data to the tty (ldisc) */
 225         rb = list_first_entry(&priv->tty_inqueue, struct iucv_tty_buffer, list);
 226
 227         written = 0;
 228         if (!rb->mbuf) { /* message not yet received ... */
 229                 /* allocate mem to store msg data; if no memory is available
 230                  * then leave the buffer on the list and re-try later */
 231                 rb->mbuf = kmalloc(rb->msg.length, GFP_ATOMIC);
 232                 if (!rb->mbuf)
 233                         return -ENOMEM;
 234
 235                 rc = __iucv_message_receive(priv->path, &rb->msg, 0,
 236                                             rb->mbuf, rb->msg.length, NULL);
 237                 switch (rc) {
 238                 case 0: /* Successful       */
 239                         break;
 240                 case 2: /* No message found */
 241                 case 9: /* Message purged   */
 242                         break;
 243                 default:
 244                         written = -EIO;
 245                 }
 246                 /* remove buffer if an error has occured or received data
 247                  * is not correct */
 248                 if (rc || (rb->mbuf->version != MSG_VERSION) ||
 249                           (rb->msg.length    != MSG_SIZE(rb->mbuf->datalen)))
 250                         goto out_remove_buffer;
 251         }
 252
 253         switch (rb->mbuf->type) {
 254         case MSG_TYPE_DATA:
 255                 written = min_t(int, rb->mbuf->datalen - rb->offset, count);
 256                 memcpy(buf, rb->mbuf->data + rb->offset, written);
 257                 if (written < (rb->mbuf->datalen - rb->offset)) {
 258                         rb->offset += written;
 259                         *has_more_data = 1;
 260                         goto out_written;
 261                 }
 262                 break;
 263
 264         case MSG_TYPE_WINSIZE:
 265                 if (rb->mbuf->datalen != sizeof(struct winsize))
 266                         break;
 267                 hvc_resize(priv->hvc, *((struct winsize *) rb->mbuf->data));
 268                 break;
 269
 270         case MSG_TYPE_ERROR:    /* ignored ... */
 271         case MSG_TYPE_TERMENV:  /* ignored ... */
 272         case MSG_TYPE_TERMIOS:  /* ignored ... */
 273                 break;
 274         }
 275
 276 out_remove_buffer:
 277         list_del(&rb->list);
 278         destroy_tty_buffer(rb);
 279         *has_more_data = !list_empty(&priv->tty_inqueue);
 280
 281 out_written:
 282         return written;
 283 }
 284
 285 /**
 286  * hvc_iucv_get_chars() - HVC get_chars operation.
 287  * @vtermno:    HVC virtual terminal number.
 288  * @buf:        Pointer to a buffer to store data
 289  * @count:      Size of buffer available for writing
 290  *
 291  * The HVC thread calls this method to read characters from the back-end.
 292  * If an IUCV communication path has been established, pending IUCV messages
 293  * are received and data is copied into buffer @buf up to @count bytes.
 294  *
 295  * Locking:     The routine gets called under an irqsave() spinlock; and
 296  *              the routine locks the struct hvc_iucv_private->lock to call
 297  *              helper functions.
 298  */
 299 static int hvc_iucv_get_chars(uint32_t vtermno, char *buf, int count)
 300 {
 301         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 302         int written;
 303         int has_more_data;
 304
 305         if (count <= 0)
 306                 return 0;
 307
 308         if (!priv)
 309                 return -ENODEV;
 310
 311         spin_lock(&priv->lock);
 312         has_more_data = 0;
 313         written = hvc_iucv_write(priv, buf, count, &has_more_data);
 314         spin_unlock(&priv->lock);
 315
 316         /* if there are still messages on the queue... schedule another run */
 317         if (has_more_data)
 318                 hvc_kick();
 319
 320         return written;
 321 }
 322
 323 /**
 324  * hvc_iucv_queue() - Buffer terminal data for sending.
 325  * @priv:       Pointer to struct hvc_iucv_private instance.
 326  * @buf:        Buffer containing data to send.
 327  * @count:      Size of buffer and amount of data to send.
 328  *
 329  * The function queues data for sending. To actually send the buffered data,
 330  * a work queue function is scheduled (with QUEUE_SNDBUF_DELAY).
 331  * The function returns the number of data bytes that has been buffered.
 332  *
 333  * If the device is not connected, data is ignored and the function returns
 334  * @count.
 335  * If the buffer is full, the function returns 0.
 336  * If an existing IUCV communicaton path has been severed, -EPIPE is returned
 337  * (that can be passed to HVC layer to cause a tty hangup).
 338  */
 339 static int hvc_iucv_queue(struct hvc_iucv_private *priv, const char *buf,
 340                           int count)
 341 {
 342         size_t len;
 343
 344         if (priv->iucv_state == IUCV_DISCONN)
 345                 return count;                   /* ignore data */
 346
 347         if (priv->iucv_state == IUCV_SEVERED)
 348                 return -EPIPE;
 349
 350         len = min_t(size_t, count, SNDBUF_SIZE - priv->sndbuf_len);
 351         if (!len)
 352                 return 0;
 353
 354         memcpy(priv->sndbuf + priv->sndbuf_len, buf, len);
 355         priv->sndbuf_len += len;
 356
 357         if (priv->iucv_state == IUCV_CONNECTED)
 358                 schedule_delayed_work(&priv->sndbuf_work, QUEUE_SNDBUF_DELAY);
 359
 360         return len;
 361 }
 362
 363 /**
 364  * hvc_iucv_send() - Send an IUCV message containing terminal data.
 365  * @priv:       Pointer to struct hvc_iucv_private instance.
 366  *
 367  * If an IUCV communication path has been established, the buffered output data
 368  * is sent via an IUCV message and the number of bytes sent is returned.
 369  * Returns 0 if there is no established IUCV communication path or
 370  * -EPIPE if an existing IUCV communicaton path has been severed.
 371  */
 372 static int hvc_iucv_send(struct hvc_iucv_private *priv)
 373 {
 374         struct iucv_tty_buffer *sb;
 375         int rc, len;
 376
 377         if (priv->iucv_state == IUCV_SEVERED)
 378                 return -EPIPE;
 379
 380         if (priv->iucv_state == IUCV_DISCONN)
 381                 return -EIO;
 382
 383         if (!priv->sndbuf_len)
 384                 return 0;
 385
 386         /* allocate internal buffer to store msg data and also compute total
 387          * message length */
 388         sb = alloc_tty_buffer(priv->sndbuf_len, GFP_ATOMIC);
 389         if (!sb)
 390                 return -ENOMEM;
 391
 392         memcpy(sb->mbuf->data, priv->sndbuf, priv->sndbuf_len);
 393         sb->mbuf->datalen = (u16) priv->sndbuf_len;
 394         sb->msg.length = MSG_SIZE(sb->mbuf->datalen);
 395
 396         list_add_tail(&sb->list, &priv->tty_outqueue);
 397
 398         rc = __iucv_message_send(priv->path, &sb->msg, 0, 0,
 399                                  (void *) sb->mbuf, sb->msg.length);
 400         if (rc) {
 401                 /* drop the message here; however we might want to handle
 402                  * 0x03 (msg limit reached) by trying again... */
 403                 list_del(&sb->list);
 404                 destroy_tty_buffer(sb);
 405         }
 406         len = priv->sndbuf_len;
 407         priv->sndbuf_len = 0;
 408
 409         return len;
 410 }
 411
 412 /**
 413  * hvc_iucv_sndbuf_work() - Send buffered data over IUCV
 414  * @work:       Work structure.
 415  *
 416  * This work queue function sends buffered output data over IUCV and,
 417  * if not all buffered data could be sent, reschedules itself.
 418  */
 419 static void hvc_iucv_sndbuf_work(struct work_struct *work)
 420 {
 421         struct hvc_iucv_private *priv;
 422
 423         priv = container_of(work, struct hvc_iucv_private, sndbuf_work.work);
 424         if (!priv)
 425                 return;
 426
 427         spin_lock_bh(&priv->lock);
 428         hvc_iucv_send(priv);
 429         spin_unlock_bh(&priv->lock);
 430 }
 431
 432 /**
 433  * hvc_iucv_put_chars() - HVC put_chars operation.
 434  * @vtermno:    HVC virtual terminal number.
 435  * @buf:        Pointer to an buffer to read data from
 436  * @count:      Size of buffer available for reading
 437  *
 438  * The HVC thread calls this method to write characters to the back-end.
 439  * The function calls hvc_iucv_queue() to queue terminal data for sending.
 440  *
 441  * Locking:     The method gets called under an irqsave() spinlock; and
 442  *              locks struct hvc_iucv_private->lock.
 443  */
 444 static int hvc_iucv_put_chars(uint32_t vtermno, const char *buf, int count)
 445 {
 446         struct hvc_iucv_private *priv = hvc_iucv_get_private(vtermno);
 447         int queued;
 448
 449         if (count <= 0)
 450                 return 0;
 451
 452         if (!priv)
 453                 return -ENODEV;
 454
 455         spin_lock(&priv->lock);
 456         queued = hvc_iucv_queue(priv, buf, count);
 457         spin_unlock(&priv->lock);
 458
 459         return queued;
 460 }
 461
 462 /**
 463  * hvc_iucv_notifier_add() - HVC notifier for opening a TTY for the first time.
 464  * @hp: Pointer to the HVC device (struct hvc_struct)
 465  * @id: Additional data (originally passed to hvc_alloc): the index of an struct
 466  *      hvc_iucv_private instance.
 467  *
 468  * The function sets the tty state to TTY_OPENED for the struct hvc_iucv_private
 469  * instance that is derived from @id. Always returns 0.
 470  *
 471  * Locking:     struct hvc_iucv_private->lock, spin_lock_bh
 472  */
 473 static int hvc_iucv_notifier_add(struct hvc_struct *hp, int id)
 474 {
 475         struct hvc_iucv_private *priv;
 476
 477         priv = hvc_iucv_get_private(id);
 478         if (!priv)
 479                 return 0;
 480
 481         spin_lock_bh(&priv->lock);
 482         priv->tty_state = TTY_OPENED;
 483         spin_unlock_bh(&priv->lock);
 484
 485         return 0;
 486 }
 487
 488 /**
 489  * hvc_iucv_cleanup() - Clean up and reset a z/VM IUCV HVC instance.
 490  * @priv:       Pointer to the struct hvc_iucv_private instance.
 491  */
 492 static void hvc_iucv_cleanup(struct hvc_iucv_private *priv)
 493 {
 494         destroy_tty_buffer_list(&priv->tty_outqueue);
 495         destroy_tty_buffer_list(&priv->tty_inqueue);
 496
 497         priv->tty_state = TTY_CLOSED;
 498         priv->iucv_state = IUCV_DISCONN;
 499
 500         priv->sndbuf_len = 0;
 501 }
 502
 503 /**
 504  * tty_outqueue_empty() - Test if the tty outq is empty
 505  * @priv:       Pointer to struct hvc_iucv_private instance.
 506  */
 507 static inline int tty_outqueue_empty(struct hvc_iucv_private *priv)
 508 {
 509         int rc;
 510
 511         spin_lock_bh(&priv->lock);
 512         rc = list_empty(&priv->tty_outqueue);
 513         spin_unlock_bh(&priv->lock);
 514
 515         return rc;
 516 }
 517
 518 /**
 519  * flush_sndbuf_sync() - Flush send buffer and wait for completion
 520  * @priv:       Pointer to struct hvc_iucv_private instance.
 521  *
 522  * The routine cancels a pending sndbuf work, calls hvc_iucv_send()
 523  * to flush any buffered terminal output data and waits for completion.
 524  */
 525 static void flush_sndbuf_sync(struct hvc_iucv_private *priv)
 526 {
 527         int sync_wait;
 528
 529         cancel_delayed_work_sync(&priv->sndbuf_work);
 530
 531         spin_lock_bh(&priv->lock);
 532         hvc_iucv_send(priv);            /* force sending buffered data */
 533         sync_wait = !list_empty(&priv->tty_outqueue); /* anything queued ? */
 534         spin_unlock_bh(&priv->lock);
 535
 536         if (sync_wait)
 537                 wait_event_timeout(priv->sndbuf_waitq,
 538                                    tty_outqueue_empty(priv), HZ);
 539 }
 540
 541 /**
 542  * hvc_iucv_notifier_hangup() - HVC notifier for TTY hangups.
 543  * @hp:         Pointer to the HVC device (struct hvc_struct)
 544  * @id:         Additional data (originally passed to hvc_alloc):
 545  *              the index of an struct hvc_iucv_private instance.
 546  *
 547  * This routine notifies the HVC back-end that a tty hangup (carrier loss,
 548  * virtual or otherwise) has occured.
 549  * The z/VM IUCV HVC device driver ignores virtual hangups (vhangup())
 550  * to keep an existing IUCV communication path established.
 551  * (Background: vhangup() is called from user space (by getty or login) to
 552  *              disable writing to the tty by other applications).
 553  * If the tty has been opened and an established IUCV path has been severed
 554  * (we caused the tty hangup), the function calls hvc_iucv_cleanup().
 555  *
 556  * Locking:     struct hvc_iucv_private->lock
 557  */
 558 static void hvc_iucv_notifier_hangup(struct hvc_struct *hp, int id)
 559 {
 560         struct hvc_iucv_private *priv;
 561
 562         priv = hvc_iucv_get_private(id);
 563         if (!priv)
 564                 return;
 565
 566         flush_sndbuf_sync(priv);
 567
 568         spin_lock_bh(&priv->lock);
 569         /* NOTE: If the hangup was scheduled by ourself (from the iucv
 570          *       path_servered callback [IUCV_SEVERED]), we have to clean up
 571          *       our structure and to set state to TTY_CLOSED.
 572          *       If the tty was hung up otherwise (e.g. vhangup()), then we
 573          *       ignore this hangup and keep an established IUCV path open...
 574          *       (...the reason is that we are not able to connect back to the
 575          *       client if we disconnect on hang up) */
 576         priv->tty_state = TTY_CLOSED;
 577
 578         if (priv->iucv_state == IUCV_SEVERED)
 579                 hvc_iucv_cleanup(priv);
 580         spin_unlock_bh(&priv->lock);
 581 }
 582
 583 /**
 584  * hvc_iucv_notifier_del() - HVC notifier for closing a TTY for the last time.
 585  * @hp:         Pointer to the HVC device (struct hvc_struct)
 586  * @id:         Additional data (originally passed to hvc_alloc):
 587  *              the index of an struct hvc_iucv_private instance.
 588  *
 589  * This routine notifies the HVC back-end that the last tty device fd has been
 590  * closed.  The function calls hvc_iucv_cleanup() to clean up the struct
 591  * hvc_iucv_private instance.
 592  *
 593  * Locking:     struct hvc_iucv_private->lock
 594  */
 595 static void hvc_iucv_notifier_del(struct hvc_struct *hp, int id)
 596 {
 597         struct hvc_iucv_private *priv;
 598         struct iucv_path        *path;
 599
 600         priv = hvc_iucv_get_private(id);
 601         if (!priv)
 602                 return;
 603
 604         flush_sndbuf_sync(priv);
 605
 606         spin_lock_bh(&priv->lock);
 607         path = priv->path;              /* save reference to IUCV path */
 608         priv->path = NULL;
 609         hvc_iucv_cleanup(priv);
 610         spin_unlock_bh(&priv->lock);
 611
 612         /* sever IUCV path outside of priv->lock due to lock ordering of:
 613          * priv->lock <--> iucv_table_lock */
 614         if (path) {
 615                 iucv_path_sever(path, NULL);
 616                 iucv_path_free(path);
 617         }
 618 }
 619
 620 /**
 621  * hvc_iucv_path_pending() - IUCV handler to process a connection request.
 622  * @path:       Pending path (struct iucv_path)
 623  * @ipvmid:     z/VM system identifier of originator
 624  * @ipuser:     User specified data for this path
 625  *              (AF_IUCV: port/service name and originator port)
 626  *
 627  * The function uses the @ipuser data to determine if the pending path belongs
 628  * to a terminal managed by this device driver.
 629  * If the path belongs to this driver, ensure that the terminal is not accessed
 630  * multiple times (only one connection to a terminal is allowed).
 631  * If the terminal is not yet connected, the pending path is accepted and is
 632  * associated to the appropriate struct hvc_iucv_private instance.
 633  *
 634  * Returns 0 if @path belongs to a terminal managed by the this device driver;
 635  * otherwise returns -ENODEV in order to dispatch this path to other handlers.
 636  *
 637  * Locking:     struct hvc_iucv_private->lock
 638  */
 639 static  int hvc_iucv_path_pending(struct iucv_path *path,
 640                                   u8 ipvmid[8], u8 ipuser[16])
 641 {
 642         struct hvc_iucv_private *priv;
 643         u8 nuser_data[16];
 644         int i, rc;
 645
 646         priv = NULL;
 647         for (i = 0; i < hvc_iucv_devices; i++)
 648                 if (hvc_iucv_table[i] &&
 649                     (0 == memcmp(hvc_iucv_table[i]->srv_name, ipuser, 8))) {
 650                         priv = hvc_iucv_table[i];
 651                         break;
 652                 }
 653         if (!priv)
 654                 return -ENODEV;
 655
 656         spin_lock(&priv->lock);
 657
 658         /* If the terminal is already connected or being severed, then sever
 659          * this path to enforce that there is only ONE established communication
 660          * path per terminal. */
 661         if (priv->iucv_state != IUCV_DISCONN) {
 662                 iucv_path_sever(path, ipuser);
 663                 iucv_path_free(path);
 664                 goto out_path_handled;
 665         }
 666
 667         /* accept path */
 668         memcpy(nuser_data, ipuser + 8, 8);  /* remote service (for af_iucv) */
 669         memcpy(nuser_data + 8, ipuser, 8);  /* local service  (for af_iucv) */
 670         path->msglim = 0xffff;              /* IUCV MSGLIMIT */
 671         path->flags &= ~IUCV_IPRMDATA;      /* TODO: use IUCV_IPRMDATA */
 672         rc = iucv_path_accept(path, &hvc_iucv_handler, nuser_data, priv);
 673         if (rc) {
 674                 iucv_path_sever(path, ipuser);
 675                 iucv_path_free(path);
 676                 goto out_path_handled;
 677         }
 678         priv->path = path;
 679         priv->iucv_state = IUCV_CONNECTED;
 680
 681         /* flush buffered output data... */
 682         schedule_delayed_work(&priv->sndbuf_work, 5);
 683
 684 out_path_handled:
 685         spin_unlock(&priv->lock);
 686         return 0;
 687 }
 688
 689 /**
 690  * hvc_iucv_path_severed() - IUCV handler to process a path sever.
 691  * @path:       Pending path (struct iucv_path)
 692  * @ipuser:     User specified data for this path
 693  *              (AF_IUCV: port/service name and originator port)
 694  *
 695  * The function also severs the path (as required by the IUCV protocol) and
 696  * sets the iucv state to IUCV_SEVERED for the associated struct
 697  * hvc_iucv_private instance. Later, the IUCV_SEVERED state triggers a tty
 698  * hangup (hvc_iucv_get_chars() / hvc_iucv_write()).
 699  * If tty portion of the HVC is closed, clean up the outqueue.
 700  *
 701  * Locking:     struct hvc_iucv_private->lock
 702  */
 703 static void hvc_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 704 {
 705         struct hvc_iucv_private *priv = path->private;
 706
 707         spin_lock(&priv->lock);
 708         priv->iucv_state = IUCV_SEVERED;
 709
 710         /* If the tty has not yet been opened, clean up the hvc_iucv_private
 711          * structure to allow re-connects.
 712          * This is also done for our console device because console hangups
 713          * are handled specially and no notifier is called by HVC.
 714          * The tty session is active (TTY_OPEN) and ready for re-connects...
 715          *
 716          * If it has been opened, let get_chars() return -EPIPE to signal the
 717          * HVC layer to hang up the tty.
 718          * If so, we need to wake up the HVC thread to call get_chars()...
 719          */
 720         priv->path = NULL;
 721         if (priv->tty_state == TTY_CLOSED)
 722                 hvc_iucv_cleanup(priv);
 723         else
 724                 if (priv->is_console) {
 725                         hvc_iucv_cleanup(priv);
 726                         priv->tty_state = TTY_OPENED;
 727                 } else
 728                         hvc_kick();
 729         spin_unlock(&priv->lock);
 730
 731         /* finally sever path (outside of priv->lock due to lock ordering) */
 732         iucv_path_sever(path, ipuser);
 733         iucv_path_free(path);
 734 }
 735
 736 /**
 737  * hvc_iucv_msg_pending() - IUCV handler to process an incoming IUCV message.
 738  * @path:       Pending path (struct iucv_path)
 739  * @msg:        Pointer to the IUCV message
 740  *
 741  * The function puts an incoming message on the input queue for later
 742  * processing (by hvc_iucv_get_chars() / hvc_iucv_write()).
 743  * If the tty has not yet been opened, the message is rejected.
 744  *
 745  * Locking:     struct hvc_iucv_private->lock
 746  */
 747 static void hvc_iucv_msg_pending(struct iucv_path *path,
 748                                  struct iucv_message *msg)
 749 {
 750         struct hvc_iucv_private *priv = path->private;
 751         struct iucv_tty_buffer *rb;
 752
 753         /* reject messages that exceed max size of iucv_tty_msg->datalen */
 754         if (msg->length > MSG_SIZE(MSG_MAX_DATALEN)) {
 755                 iucv_message_reject(path, msg);
 756                 return;
 757         }
 758
 759         spin_lock(&priv->lock);
 760
 761         /* reject messages if tty has not yet been opened */
 762         if (priv->tty_state == TTY_CLOSED) {
 763                 iucv_message_reject(path, msg);
 764                 goto unlock_return;
 765         }
 766
 767         /* allocate tty buffer to save iucv msg only */
 768         rb = alloc_tty_buffer(0, GFP_ATOMIC);
 769         if (!rb) {
 770                 iucv_message_reject(path, msg);
 771                 goto unlock_return;     /* -ENOMEM */
 772         }
 773         rb->msg = *msg;
 774
 775         list_add_tail(&rb->list, &priv->tty_inqueue);
 776
 777         hvc_kick();     /* wake up hvc thread */
 778
 779 unlock_return:
 780         spin_unlock(&priv->lock);
 781 }
 782
 783 /**
 784  * hvc_iucv_msg_complete() - IUCV handler to process message completion
 785  * @path:       Pending path (struct iucv_path)
 786  * @msg:        Pointer to the IUCV message
 787  *
 788  * The function is called upon completion of message delivery to remove the
 789  * message from the outqueue. Additional delivery information can be found
 790  * msg->audit: rejected messages (0x040000 (IPADRJCT)), and
 791  *             purged messages   (0x010000 (IPADPGNR)).
 792  *
 793  * Locking:     struct hvc_iucv_private->lock
 794  */
 795 static void hvc_iucv_msg_complete(struct iucv_path *path,
 796                                   struct iucv_message *msg)
 797 {
 798         struct hvc_iucv_private *priv = path->private;
 799         struct iucv_tty_buffer  *ent, *next;
 800         LIST_HEAD(list_remove);
 801
 802         spin_lock(&priv->lock);
 803         list_for_each_entry_safe(ent, next, &priv->tty_outqueue, list)
 804                 if (ent->msg.id == msg->id) {
 805                         list_move(&ent->list, &list_remove);
 806                         break;
 807                 }
 808         wake_up(&priv->sndbuf_waitq);
 809         spin_unlock(&priv->lock);
 810         destroy_tty_buffer_list(&list_remove);
 811 }
 812
 813
 814 /* HVC operations */
 815 static struct hv_ops hvc_iucv_ops = {
 816         .get_chars = hvc_iucv_get_chars,
 817         .put_chars = hvc_iucv_put_chars,
 818         .notifier_add = hvc_iucv_notifier_add,
 819         .notifier_del = hvc_iucv_notifier_del,
 820         .notifier_hangup = hvc_iucv_notifier_hangup,
 821 };
 822
 823 /**
 824  * hvc_iucv_alloc() - Allocates a new struct hvc_iucv_private instance
 825  * @id:                 hvc_iucv_table index
 826  * @is_console:         Flag if the instance is used as Linux console
 827  *
 828  * This function allocates a new hvc_iucv_private structure and stores
 829  * the instance in hvc_iucv_table at index @id.
 830  * Returns 0 on success; otherwise non-zero.
 831  */
 832 static int __init hvc_iucv_alloc(int id, unsigned int is_console)
 833 {
 834         struct hvc_iucv_private *priv;
 835         char name[9];
 836         int rc;
 837
 838         priv = kzalloc(sizeof(struct hvc_iucv_private), GFP_KERNEL);
 839         if (!priv)
 840                 return -ENOMEM;
 841
 842         spin_lock_init(&priv->lock);
 843         INIT_LIST_HEAD(&priv->tty_outqueue);
 844         INIT_LIST_HEAD(&priv->tty_inqueue);
 845         INIT_DELAYED_WORK(&priv->sndbuf_work, hvc_iucv_sndbuf_work);
 846         init_waitqueue_head(&priv->sndbuf_waitq);
 847
 848         priv->sndbuf = (void *) get_zeroed_page(GFP_KERNEL);
 849         if (!priv->sndbuf) {
 850                 kfree(priv);
 851                 return -ENOMEM;
 852         }
 853
 854         /* set console flag */
 855         priv->is_console = is_console;
 856
 857         /* finally allocate hvc */
 858         priv->hvc = hvc_alloc(HVC_IUCV_MAGIC + id, /*             PAGE_SIZE */
 859                               HVC_IUCV_MAGIC + id, &hvc_iucv_ops, 256);
 860         if (IS_ERR(priv->hvc)) {
 861                 rc = PTR_ERR(priv->hvc);
 862                 free_page((unsigned long) priv->sndbuf);
 863                 kfree(priv);
 864                 return rc;
 865         }
 866
 867         /* notify HVC thread instead of using polling */
 868         priv->hvc->irq_requested = 1;
 869
 870         /* setup iucv related information */
 871         snprintf(name, 9, "lnxhvc%-2d", id);
 872         memcpy(priv->srv_name, name, 8);
 873         ASCEBC(priv->srv_name, 8);
 874
 875         hvc_iucv_table[id] = priv;
 876         return 0;
 877 }
 878
 879 /**
 880  * hvc_iucv_init() - z/VM IUCV HVC device driver initialization
 881  */
 882 static int __init hvc_iucv_init(void)
 883 {
 884         int rc;
 885         unsigned int i;
 886
 887         if (!MACHINE_IS_VM) {
 888                 pr_info("The z/VM IUCV HVC device driver cannot "
 889                            "be used without z/VM\n");
 890                 return -ENODEV;
 891         }
 892
 893         if (!hvc_iucv_devices)
 894                 return -ENODEV;
 895
 896         if (hvc_iucv_devices > MAX_HVC_IUCV_LINES)
 897                 return -EINVAL;
 898
 899         hvc_iucv_buffer_cache = kmem_cache_create(KMSG_COMPONENT,
 900                                            sizeof(struct iucv_tty_buffer),
 901                                            0, 0, NULL);
 902         if (!hvc_iucv_buffer_cache) {
 903                 pr_err("Allocating memory failed with reason code=%d\n", 1);
 904                 return -ENOMEM;
 905         }
 906
 907         hvc_iucv_mempool = mempool_create_slab_pool(MEMPOOL_MIN_NR,
 908                                                     hvc_iucv_buffer_cache);
 909         if (!hvc_iucv_mempool) {
 910                 pr_err("Allocating memory failed with reason code=%d\n", 2);
 911                 kmem_cache_destroy(hvc_iucv_buffer_cache);
 912                 return -ENOMEM;
 913         }
 914
 915         /* register the first terminal device as console
 916          * (must be done before allocating hvc terminal devices) */
 917         rc = hvc_instantiate(HVC_IUCV_MAGIC, IUCV_HVC_CON_IDX, &hvc_iucv_ops);
 918         if (rc) {
 919                 pr_err("Registering HVC terminal device as "
 920                        "Linux console failed\n");
 921                 goto out_error_memory;
 922         }
 923
 924         /* allocate hvc_iucv_private structs */
 925         for (i = 0; i < hvc_iucv_devices; i++) {
 926                 rc = hvc_iucv_alloc(i, (i == IUCV_HVC_CON_IDX) ? 1 : 0);
 927                 if (rc) {
 928                         pr_err("Creating a new HVC terminal device "
 929                                 "failed with error code=%d\n", rc);
 930                         goto out_error_hvc;
 931                 }
 932         }
 933
 934         /* register IUCV callback handler */
 935         rc = iucv_register(&hvc_iucv_handler, 0);
 936         if (rc) {
 937                 pr_err("Registering IUCV handlers failed with error code=%d\n",
 938                         rc);
 939                 goto out_error_iucv;
 940         }
 941
 942         return 0;
 943
 944 out_error_iucv:
 945         iucv_unregister(&hvc_iucv_handler, 0);
 946 out_error_hvc:
 947         for (i = 0; i < hvc_iucv_devices; i++)
 948                 if (hvc_iucv_table[i]) {
 949                         if (hvc_iucv_table[i]->hvc)
 950                                 hvc_remove(hvc_iucv_table[i]->hvc);
 951                         kfree(hvc_iucv_table[i]);
 952                 }
 953 out_error_memory:
 954         mempool_destroy(hvc_iucv_mempool);
 955         kmem_cache_destroy(hvc_iucv_buffer_cache);
 956         return rc;
 957 }
 958
 959 /**
 960  * hvc_iucv_config() - Parsing of hvc_iucv=  kernel command line parameter
 961  * @val:        Parameter value (numeric)
 962  */
 963 static  int __init hvc_iucv_config(char *val)
 964 {
 965          return strict_strtoul(val, 10, &hvc_iucv_devices);
 966 }
 967
 968
 969 device_initcall(hvc_iucv_init);
 970 __setup("hvc_iucv=", hvc_iucv_config);