drivers/s390/char/sclp_rw.c

   1 /*
   2  * driver: reading from and writing to system console on S/390 via SCLP
   3  *
   4  * Copyright IBM Corp. 1999, 2009
   5  *
   6  * Author(s): Martin Peschke <mpeschke@de.ibm.com>
   7  *            Martin Schwidefsky <schwidefsky@de.ibm.com>
   8  */
   9
  10 #include <linux/kmod.h>
  11 #include <linux/types.h>
  12 #include <linux/err.h>
  13 #include <linux/string.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/ctype.h>
  16 #include <asm/uaccess.h>
  17
  18 #include "sclp.h"
  19 #include "sclp_rw.h"
  20
  21 /*
  22  * The room for the SCCB (only for writing) is not equal to a pages size
  23  * (as it is specified as the maximum size in the SCLP documentation)
  24  * because of the additional data structure described above.
  25  */
  26 #define MAX_SCCB_ROOM (PAGE_SIZE - sizeof(struct sclp_buffer))
  27
  28 static void sclp_rw_pm_event(struct sclp_register *reg,
  29                              enum sclp_pm_event sclp_pm_event)
  30 {
  31         sclp_console_pm_event(sclp_pm_event);
  32 }
  33
  34 /* Event type structure for write message and write priority message */
  35 static struct sclp_register sclp_rw_event = {
  36         .send_mask = EVTYP_MSG_MASK | EVTYP_PMSGCMD_MASK,
  37         .pm_event_fn = sclp_rw_pm_event,
  38 };
  39
  40 /*
  41  * Setup a sclp write buffer. Gets a page as input (4K) and returns
  42  * a pointer to a struct sclp_buffer structure that is located at the
  43  * end of the input page. This reduces the buffer space by a few
  44  * bytes but simplifies things.
  45  */
  46 struct sclp_buffer *
  47 sclp_make_buffer(void *page, unsigned short columns, unsigned short htab)
  48 {
  49         struct sclp_buffer *buffer;
  50         struct write_sccb *sccb;
  51
  52         sccb = (struct write_sccb *) page;
  53         /*
  54          * We keep the struct sclp_buffer structure at the end
  55          * of the sccb page.
  56          */
  57         buffer = ((struct sclp_buffer *) ((addr_t) sccb + PAGE_SIZE)) - 1;
  58         buffer->sccb = sccb;
  59         buffer->retry_count = 0;
  60         buffer->mto_number = 0;
  61         buffer->mto_char_sum = 0;
  62         buffer->current_line = NULL;
  63         buffer->current_length = 0;
  64         buffer->columns = columns;
  65         buffer->htab = htab;
  66
  67         /* initialize sccb */
  68         memset(sccb, 0, sizeof(struct write_sccb));
  69         sccb->header.length = sizeof(struct write_sccb);
  70         sccb->msg_buf.header.length = sizeof(struct msg_buf);
  71         sccb->msg_buf.header.type = EVTYP_MSG;
  72         sccb->msg_buf.mdb.header.length = sizeof(struct mdb);
  73         sccb->msg_buf.mdb.header.type = 1;
  74         sccb->msg_buf.mdb.header.tag = 0xD4C4C240;      /* ebcdic "MDB " */
  75         sccb->msg_buf.mdb.header.revision_code = 1;
  76         sccb->msg_buf.mdb.go.length = sizeof(struct go);
  77         sccb->msg_buf.mdb.go.type = 1;
  78
  79         return buffer;
  80 }
  81
  82 /*
  83  * Return a pointer to the original page that has been used to create
  84  * the buffer.
  85  */
  86 void *
  87 sclp_unmake_buffer(struct sclp_buffer *buffer)
  88 {
  89         return buffer->sccb;
  90 }
  91
  92 /*
  93  * Initialize a new Message Text Object (MTO) at the end of the provided buffer
  94  * with enough room for max_len characters. Return 0 on success.
  95  */
  96 static int
  97 sclp_initialize_mto(struct sclp_buffer *buffer, int max_len)
  98 {
  99         struct write_sccb *sccb;
 100         struct mto *mto;
 101         int mto_size;
 102
 103         /* max size of new Message Text Object including message text  */
 104         mto_size = sizeof(struct mto) + max_len;
 105
 106         /* check if current buffer sccb can contain the mto */
 107         sccb = buffer->sccb;
 108         if ((MAX_SCCB_ROOM - sccb->header.length) < mto_size)
 109                 return -ENOMEM;
 110
 111         /* find address of new message text object */
 112         mto = (struct mto *)(((addr_t) sccb) + sccb->header.length);
 113
 114         /*
 115          * fill the new Message-Text Object,
 116          * starting behind the former last byte of the SCCB
 117          */
 118         memset(mto, 0, sizeof(struct mto));
 119         mto->length = sizeof(struct mto);
 120         mto->type = 4;  /* message text object */
 121         mto->line_type_flags = LNTPFLGS_ENDTEXT; /* end text */
 122
 123         /* set pointer to first byte after struct mto. */
 124         buffer->current_line = (char *) (mto + 1);
 125         buffer->current_length = 0;
 126
 127         return 0;
 128 }
 129
 130 /*
 131  * Finalize MTO initialized by sclp_initialize_mto(), updating the sizes of
 132  * MTO, enclosing MDB, event buffer and SCCB.
 133  */
 134 static void
 135 sclp_finalize_mto(struct sclp_buffer *buffer)
 136 {
 137         struct write_sccb *sccb;
 138         struct mto *mto;
 139         int str_len, mto_size;
 140
 141         str_len = buffer->current_length;
 142         buffer->current_line = NULL;
 143         buffer->current_length = 0;
 144
 145         /* real size of new Message Text Object including message text  */
 146         mto_size = sizeof(struct mto) + str_len;
 147
 148         /* find address of new message text object */
 149         sccb = buffer->sccb;
 150         mto = (struct mto *)(((addr_t) sccb) + sccb->header.length);
 151
 152         /* set size of message text object */
 153         mto->length = mto_size;
 154
 155         /*
 156          * update values of sizes
 157          * (SCCB, Event(Message) Buffer, Message Data Block)
 158          */
 159         sccb->header.length += mto_size;
 160         sccb->msg_buf.header.length += mto_size;
 161         sccb->msg_buf.mdb.header.length += mto_size;
 162
 163         /*
 164          * count number of buffered messages (= number of Message Text
 165          * Objects) and number of buffered characters
 166          * for the SCCB currently used for buffering and at all
 167          */
 168         buffer->mto_number++;
 169         buffer->mto_char_sum += str_len;
 170 }
 171
 172 /*
 173  * processing of a message including escape characters,
 174  * returns number of characters written to the output sccb
 175  * ("processed" means that is not guaranteed that the character have already
 176  *  been sent to the SCLP but that it will be done at least next time the SCLP
 177  *  is not busy)
 178  */
 179 int
 180 sclp_write(struct sclp_buffer *buffer, const unsigned char *msg, int count)
 181 {
 182         int spaces, i_msg;
 183         int rc;
 184
 185         /*
 186          * parse msg for escape sequences (\t,\v ...) and put formated
 187          * msg into an mto (created by sclp_initialize_mto).
 188          *
 189          * We have to do this work ourselfs because there is no support for
 190          * these characters on the native machine and only partial support
 191          * under VM (Why does VM interpret \n but the native machine doesn't ?)
 192          *
 193          * Depending on i/o-control setting the message is always written
 194          * immediately or we wait for a final new line maybe coming with the
 195          * next message. Besides we avoid a buffer overrun by writing its
 196          * content.
 197          *
 198          * RESTRICTIONS:
 199          *
 200          * \r and \b work within one line because we are not able to modify
 201          * previous output that have already been accepted by the SCLP.
 202          *
 203          * \t combined with following \r is not correctly represented because
 204          * \t is expanded to some spaces but \r does not know about a
 205          * previous \t and decreases the current position by one column.
 206          * This is in order to a slim and quick implementation.
 207          */
 208         for (i_msg = 0; i_msg < count; i_msg++) {
 209                 switch (msg[i_msg]) {
 210                 case '\n':      /* new line, line feed (ASCII)  */
 211                         /* check if new mto needs to be created */
 212                         if (buffer->current_line == NULL) {
 213                                 rc = sclp_initialize_mto(buffer, 0);
 214                                 if (rc)
 215                                         return i_msg;
 216                         }
 217                         sclp_finalize_mto(buffer);
 218                         break;
 219                 case '\a':      /* bell, one for several times  */
 220                         /* set SCLP sound alarm bit in General Object */
 221                         buffer->sccb->msg_buf.mdb.go.general_msg_flags |=
 222                                 GNRLMSGFLGS_SNDALRM;
 223                         break;
 224                 case '\t':      /* horizontal tabulator  */
 225                         /* check if new mto needs to be created */
 226                         if (buffer->current_line == NULL) {
 227                                 rc = sclp_initialize_mto(buffer,
 228                                                          buffer->columns);
 229                                 if (rc)
 230                                         return i_msg;
 231                         }
 232                         /* "go to (next htab-boundary + 1, same line)" */
 233                         do {
 234                                 if (buffer->current_length >= buffer->columns)
 235                                         break;
 236                                 /* ok, add a blank */
 237                                 *buffer->current_line++ = 0x40;
 238                                 buffer->current_length++;
 239                         } while (buffer->current_length % buffer->htab);
 240                         break;
 241                 case '\f':      /* form feed  */
 242                 case '\v':      /* vertical tabulator  */
 243                         /* "go to (actual column, actual line + 1)" */
 244                         /* = new line, leading spaces */
 245                         if (buffer->current_line != NULL) {
 246                                 spaces = buffer->current_length;
 247                                 sclp_finalize_mto(buffer);
 248                                 rc = sclp_initialize_mto(buffer,
 249                                                          buffer->columns);
 250                                 if (rc)
 251                                         return i_msg;
 252                                 memset(buffer->current_line, 0x40, spaces);
 253                                 buffer->current_line += spaces;
 254                                 buffer->current_length = spaces;
 255                         } else {
 256                                 /* one an empty line this is the same as \n */
 257                                 rc = sclp_initialize_mto(buffer,
 258                                                          buffer->columns);
 259                                 if (rc)
 260                                         return i_msg;
 261                                 sclp_finalize_mto(buffer);
 262                         }
 263                         break;
 264                 case '\b':      /* backspace  */
 265                         /* "go to (actual column - 1, actual line)" */
 266                         /* decrement counter indicating position, */
 267                         /* do not remove last character */
 268                         if (buffer->current_line != NULL &&
 269                             buffer->current_length > 0) {
 270                                 buffer->current_length--;
 271                                 buffer->current_line--;
 272                         }
 273                         break;
 274                 case 0x00:      /* end of string  */
 275                         /* transfer current line to SCCB */
 276                         if (buffer->current_line != NULL)
 277                                 sclp_finalize_mto(buffer);
 278                         /* skip the rest of the message including the 0 byte */
 279                         i_msg = count - 1;
 280                         break;
 281                 default:        /* no escape character  */
 282                         /* do not output unprintable characters */
 283                         if (!isprint(msg[i_msg]))
 284                                 break;
 285                         /* check if new mto needs to be created */
 286                         if (buffer->current_line == NULL) {
 287                                 rc = sclp_initialize_mto(buffer,
 288                                                          buffer->columns);
 289                                 if (rc)
 290                                         return i_msg;
 291                         }
 292                         *buffer->current_line++ = sclp_ascebc(msg[i_msg]);
 293                         buffer->current_length++;
 294                         break;
 295                 }
 296                 /* check if current mto is full */
 297                 if (buffer->current_line != NULL &&
 298                     buffer->current_length >= buffer->columns)
 299                         sclp_finalize_mto(buffer);
 300         }
 301
 302         /* return number of processed characters */
 303         return i_msg;
 304 }
 305
 306 /*
 307  * Return the number of free bytes in the sccb
 308  */
 309 int
 310 sclp_buffer_space(struct sclp_buffer *buffer)
 311 {
 312         int count;
 313
 314         count = MAX_SCCB_ROOM - buffer->sccb->header.length;
 315         if (buffer->current_line != NULL)
 316                 count -= sizeof(struct mto) + buffer->current_length;
 317         return count;
 318 }
 319
 320 /*
 321  * Return number of characters in buffer
 322  */
 323 int
 324 sclp_chars_in_buffer(struct sclp_buffer *buffer)
 325 {
 326         int count;
 327
 328         count = buffer->mto_char_sum;
 329         if (buffer->current_line != NULL)
 330                 count += buffer->current_length;
 331         return count;
 332 }
 333
 334 /*
 335  * sets or provides some values that influence the drivers behaviour
 336  */
 337 void
 338 sclp_set_columns(struct sclp_buffer *buffer, unsigned short columns)
 339 {
 340         buffer->columns = columns;
 341         if (buffer->current_line != NULL &&
 342             buffer->current_length > buffer->columns)
 343                 sclp_finalize_mto(buffer);
 344 }
 345
 346 void
 347 sclp_set_htab(struct sclp_buffer *buffer, unsigned short htab)
 348 {
 349         buffer->htab = htab;
 350 }
 351
 352 /*
 353  * called by sclp_console_init and/or sclp_tty_init
 354  */
 355 int
 356 sclp_rw_init(void)
 357 {
 358         static int init_done = 0;
 359         int rc;
 360
 361         if (init_done)
 362                 return 0;
 363
 364         rc = sclp_register(&sclp_rw_event);
 365         if (rc == 0)
 366                 init_done = 1;
 367         return rc;
 368 }
 369
 370 #define SCLP_BUFFER_MAX_RETRY           1
 371
 372 /*
 373  * second half of Write Event Data-function that has to be done after
 374  * interruption indicating completion of Service Call.
 375  */
 376 static void
 377 sclp_writedata_callback(struct sclp_req *request, void *data)
 378 {
 379         int rc;
 380         struct sclp_buffer *buffer;
 381         struct write_sccb *sccb;
 382
 383         buffer = (struct sclp_buffer *) data;
 384         sccb = buffer->sccb;
 385
 386         if (request->status == SCLP_REQ_FAILED) {
 387                 if (buffer->callback != NULL)
 388                         buffer->callback(buffer, -EIO);
 389                 return;
 390         }
 391         /* check SCLP response code and choose suitable action  */
 392         switch (sccb->header.response_code) {
 393         case 0x0020 :
 394                 /* Normal completion, buffer processed, message(s) sent */
 395                 rc = 0;
 396                 break;
 397
 398         case 0x0340: /* Contained SCLP equipment check */
 399                 if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {
 400                         rc = -EIO;
 401                         break;
 402                 }
 403                 /* remove processed buffers and requeue rest */
 404                 if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
 405                         /* not all buffers were processed */
 406                         sccb->header.response_code = 0x0000;
 407                         buffer->request.status = SCLP_REQ_FILLED;
 408                         rc = sclp_add_request(request);
 409                         if (rc == 0)
 410                                 return;
 411                 } else
 412                         rc = 0;
 413                 break;
 414
 415         case 0x0040: /* SCLP equipment check */
 416         case 0x05f0: /* Target resource in improper state */
 417                 if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {
 418                         rc = -EIO;
 419                         break;
 420                 }
 421                 /* retry request */
 422                 sccb->header.response_code = 0x0000;
 423                 buffer->request.status = SCLP_REQ_FILLED;
 424                 rc = sclp_add_request(request);
 425                 if (rc == 0)
 426                         return;
 427                 break;
 428         default:
 429                 if (sccb->header.response_code == 0x71f0)
 430                         rc = -ENOMEM;
 431                 else
 432                         rc = -EINVAL;
 433                 break;
 434         }
 435         if (buffer->callback != NULL)
 436                 buffer->callback(buffer, rc);
 437 }
 438
 439 /*
 440  * Setup the request structure in the struct sclp_buffer to do SCLP Write
 441  * Event Data and pass the request to the core SCLP loop. Return zero on
 442  * success, non-zero otherwise.
 443  */
 444 int
 445 sclp_emit_buffer(struct sclp_buffer *buffer,
 446                  void (*callback)(struct sclp_buffer *, int))
 447 {
 448         struct write_sccb *sccb;
 449
 450         /* add current line if there is one */
 451         if (buffer->current_line != NULL)
 452                 sclp_finalize_mto(buffer);
 453
 454         /* Are there messages in the output buffer ? */
 455         if (buffer->mto_number == 0)
 456                 return -EIO;
 457
 458         sccb = buffer->sccb;
 459         if (sclp_rw_event.sclp_receive_mask & EVTYP_MSG_MASK)
 460                 /* Use normal write message */
 461                 sccb->msg_buf.header.type = EVTYP_MSG;
 462         else if (sclp_rw_event.sclp_receive_mask & EVTYP_PMSGCMD_MASK)
 463                 /* Use write priority message */
 464                 sccb->msg_buf.header.type = EVTYP_PMSGCMD;
 465         else
 466                 return -ENOSYS;
 467         buffer->request.command = SCLP_CMDW_WRITE_EVENT_DATA;
 468         buffer->request.status = SCLP_REQ_FILLED;
 469         buffer->request.callback = sclp_writedata_callback;
 470         buffer->request.callback_data = buffer;
 471         buffer->request.sccb = sccb;
 472         buffer->callback = callback;
 473         return sclp_add_request(&buffer->request);
 474 }