drivers/s390/char/sclp_rw.c

   1 /*
   2  *  drivers/s390/char/sclp_rw.c
   3  *     driver: reading from and writing to system console on S/390 via SCLP
   4  *
   5  *  S390 version
   6  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
   7  *    Author(s): Martin Peschke <mpeschke@de.ibm.com>
   8  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
   9  */
  10
  11 #include <linux/config.h>
  12 #include <linux/kmod.h>
  13 #include <linux/types.h>
  14 #include <linux/err.h>
  15 #include <linux/string.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/ctype.h>
  18 #include <asm/uaccess.h>
  19
  20 #include "sclp.h"
  21 #include "sclp_rw.h"
  22
  23 #define SCLP_RW_PRINT_HEADER "sclp low level driver: "
  24
  25 /*
  26  * The room for the SCCB (only for writing) is not equal to a pages size
  27  * (as it is specified as the maximum size in the the SCLP ducumentation)
  28  * because of the additional data structure described above.
  29  */
  30 #define MAX_SCCB_ROOM (PAGE_SIZE - sizeof(struct sclp_buffer))
  31
  32 /* Event type structure for write message and write priority message */
  33 static struct sclp_register sclp_rw_event = {
  34         .send_mask = EvTyp_Msg_Mask | EvTyp_PMsgCmd_Mask
  35 };
  36
  37 /*
  38  * Setup a sclp write buffer. Gets a page as input (4K) and returns
  39  * a pointer to a struct sclp_buffer structure that is located at the
  40  * end of the input page. This reduces the buffer space by a few
  41  * bytes but simplifies things.
  42  */
  43 struct sclp_buffer *
  44 sclp_make_buffer(void *page, unsigned short columns, unsigned short htab)
  45 {
  46         struct sclp_buffer *buffer;
  47         struct write_sccb *sccb;
  48
  49         sccb = (struct write_sccb *) page;
  50         /*
  51          * We keep the struct sclp_buffer structure at the end
  52          * of the sccb page.
  53          */
  54         buffer = ((struct sclp_buffer *) ((addr_t) sccb + PAGE_SIZE)) - 1;
  55         buffer->sccb = sccb;
  56         buffer->retry_count = 0;
  57         buffer->mto_number = 0;
  58         buffer->mto_char_sum = 0;
  59         buffer->current_line = NULL;
  60         buffer->current_length = 0;
  61         buffer->columns = columns;
  62         buffer->htab = htab;
  63
  64         /* initialize sccb */
  65         memset(sccb, 0, sizeof(struct write_sccb));
  66         sccb->header.length = sizeof(struct write_sccb);
  67         sccb->msg_buf.header.length = sizeof(struct msg_buf);
  68         sccb->msg_buf.header.type = EvTyp_Msg;
  69         sccb->msg_buf.mdb.header.length = sizeof(struct mdb);
  70         sccb->msg_buf.mdb.header.type = 1;
  71         sccb->msg_buf.mdb.header.tag = 0xD4C4C240;      /* ebcdic "MDB " */
  72         sccb->msg_buf.mdb.header.revision_code = 1;
  73         sccb->msg_buf.mdb.go.length = sizeof(struct go);
  74         sccb->msg_buf.mdb.go.type = 1;
  75
  76         return buffer;
  77 }
  78
  79 /*
  80  * Return a pointer to the orignal page that has been used to create
  81  * the buffer.
  82  */
  83 void *
  84 sclp_unmake_buffer(struct sclp_buffer *buffer)
  85 {
  86         return buffer->sccb;
  87 }
  88
  89 /*
  90  * Initialize a new Message Text Object (MTO) at the end of the provided buffer
  91  * with enough room for max_len characters. Return 0 on success.
  92  */
  93 static int
  94 sclp_initialize_mto(struct sclp_buffer *buffer, int max_len)
  95 {
  96         struct write_sccb *sccb;
  97         struct mto *mto;
  98         int mto_size;
  99
 100         /* max size of new Message Text Object including message text  */
 101         mto_size = sizeof(struct mto) + max_len;
 102
 103         /* check if current buffer sccb can contain the mto */
 104         sccb = buffer->sccb;
 105         if ((MAX_SCCB_ROOM - sccb->header.length) < mto_size)
 106                 return -ENOMEM;
 107
 108         /* find address of new message text object */
 109         mto = (struct mto *)(((addr_t) sccb) + sccb->header.length);
 110
 111         /*
 112          * fill the new Message-Text Object,
 113          * starting behind the former last byte of the SCCB
 114          */
 115         memset(mto, 0, sizeof(struct mto));
 116         mto->length = sizeof(struct mto);
 117         mto->type = 4;  /* message text object */
 118         mto->line_type_flags = LnTpFlgs_EndText; /* end text */
 119
 120         /* set pointer to first byte after struct mto. */
 121         buffer->current_line = (char *) (mto + 1);
 122         buffer->current_length = 0;
 123
 124         return 0;
 125 }
 126
 127 /*
 128  * Finalize MTO initialized by sclp_initialize_mto(), updating the sizes of
 129  * MTO, enclosing MDB, event buffer and SCCB.
 130  */
 131 static void
 132 sclp_finalize_mto(struct sclp_buffer *buffer)
 133 {
 134         struct write_sccb *sccb;
 135         struct mto *mto;
 136         int str_len, mto_size;
 137
 138         str_len = buffer->current_length;
 139         buffer->current_line = NULL;
 140         buffer->current_length = 0;
 141
 142         /* real size of new Message Text Object including message text  */
 143         mto_size = sizeof(struct mto) + str_len;
 144
 145         /* find address of new message text object */
 146         sccb = buffer->sccb;
 147         mto = (struct mto *)(((addr_t) sccb) + sccb->header.length);
 148
 149         /* set size of message text object */
 150         mto->length = mto_size;
 151
 152         /*
 153          * update values of sizes
 154          * (SCCB, Event(Message) Buffer, Message Data Block)
 155          */
 156         sccb->header.length += mto_size;
 157         sccb->msg_buf.header.length += mto_size;
 158         sccb->msg_buf.mdb.header.length += mto_size;
 159
 160         /*
 161          * count number of buffered messages (= number of Message Text
 162          * Objects) and number of buffered characters
 163          * for the SCCB currently used for buffering and at all
 164          */
 165         buffer->mto_number++;
 166         buffer->mto_char_sum += str_len;
 167 }
 168
 169 /*
 170  * processing of a message including escape characters,
 171  * returns number of characters written to the output sccb
 172  * ("processed" means that is not guaranteed that the character have already
 173  *  been sent to the SCLP but that it will be done at least next time the SCLP
 174  *  is not busy)
 175  */
 176 int
 177 sclp_write(struct sclp_buffer *buffer, const unsigned char *msg, int count)
 178 {
 179         int spaces, i_msg;
 180         int rc;
 181
 182         /*
 183          * parse msg for escape sequences (\t,\v ...) and put formated
 184          * msg into an mto (created by sclp_initialize_mto).
 185          *
 186          * We have to do this work ourselfs because there is no support for
 187          * these characters on the native machine and only partial support
 188          * under VM (Why does VM interpret \n but the native machine doesn't ?)
 189          *
 190          * Depending on i/o-control setting the message is always written
 191          * immediately or we wait for a final new line maybe coming with the
 192          * next message. Besides we avoid a buffer overrun by writing its
 193          * content.
 194          *
 195          * RESTRICTIONS:
 196          *
 197          * \r and \b work within one line because we are not able to modify
 198          * previous output that have already been accepted by the SCLP.
 199          *
 200          * \t combined with following \r is not correctly represented because
 201          * \t is expanded to some spaces but \r does not know about a
 202          * previous \t and decreases the current position by one column.
 203          * This is in order to a slim and quick implementation.
 204          */
 205         for (i_msg = 0; i_msg < count; i_msg++) {
 206                 switch (msg[i_msg]) {
 207                 case '\n':      /* new line, line feed (ASCII)  */
 208                         /* check if new mto needs to be created */
 209                         if (buffer->current_line == NULL) {
 210                                 rc = sclp_initialize_mto(buffer, 0);
 211                                 if (rc)
 212                                         return i_msg;
 213                         }
 214                         sclp_finalize_mto(buffer);
 215                         break;
 216                 case '\a':      /* bell, one for several times  */
 217                         /* set SCLP sound alarm bit in General Object */
 218                         buffer->sccb->msg_buf.mdb.go.general_msg_flags |=
 219                                 GnrlMsgFlgs_SndAlrm;
 220                         break;
 221                 case '\t':      /* horizontal tabulator  */
 222                         /* check if new mto needs to be created */
 223                         if (buffer->current_line == NULL) {
 224                                 rc = sclp_initialize_mto(buffer,
 225                                                          buffer->columns);
 226                                 if (rc)
 227                                         return i_msg;
 228                         }
 229                         /* "go to (next htab-boundary + 1, same line)" */
 230                         do {
 231                                 if (buffer->current_length >= buffer->columns)
 232                                         break;
 233                                 /* ok, add a blank */
 234                                 *buffer->current_line++ = 0x40;
 235                                 buffer->current_length++;
 236                         } while (buffer->current_length % buffer->htab);
 237                         break;
 238                 case '\f':      /* form feed  */
 239                 case '\v':      /* vertical tabulator  */
 240                         /* "go to (actual column, actual line + 1)" */
 241                         /* = new line, leading spaces */
 242                         if (buffer->current_line != NULL) {
 243                                 spaces = buffer->current_length;
 244                                 sclp_finalize_mto(buffer);
 245                                 rc = sclp_initialize_mto(buffer,
 246                                                          buffer->columns);
 247                                 if (rc)
 248                                         return i_msg;
 249                                 memset(buffer->current_line, 0x40, spaces);
 250                                 buffer->current_line += spaces;
 251                                 buffer->current_length = spaces;
 252                         } else {
 253                                 /* one an empty line this is the same as \n */
 254                                 rc = sclp_initialize_mto(buffer,
 255                                                          buffer->columns);
 256                                 if (rc)
 257                                         return i_msg;
 258                                 sclp_finalize_mto(buffer);
 259                         }
 260                         break;
 261                 case '\b':      /* backspace  */
 262                         /* "go to (actual column - 1, actual line)" */
 263                         /* decrement counter indicating position, */
 264                         /* do not remove last character */
 265                         if (buffer->current_line != NULL &&
 266                             buffer->current_length > 0) {
 267                                 buffer->current_length--;
 268                                 buffer->current_line--;
 269                         }
 270                         break;
 271                 case 0x00:      /* end of string  */
 272                         /* transfer current line to SCCB */
 273                         if (buffer->current_line != NULL)
 274                                 sclp_finalize_mto(buffer);
 275                         /* skip the rest of the message including the 0 byte */
 276                         i_msg = count - 1;
 277                         break;
 278                 default:        /* no escape character  */
 279                         /* do not output unprintable characters */
 280                         if (!isprint(msg[i_msg]))
 281                                 break;
 282                         /* check if new mto needs to be created */
 283                         if (buffer->current_line == NULL) {
 284                                 rc = sclp_initialize_mto(buffer,
 285                                                          buffer->columns);
 286                                 if (rc)
 287                                         return i_msg;
 288                         }
 289                         *buffer->current_line++ = sclp_ascebc(msg[i_msg]);
 290                         buffer->current_length++;
 291                         break;
 292                 }
 293                 /* check if current mto is full */
 294                 if (buffer->current_line != NULL &&
 295                     buffer->current_length >= buffer->columns)
 296                         sclp_finalize_mto(buffer);
 297         }
 298
 299         /* return number of processed characters */
 300         return i_msg;
 301 }
 302
 303 /*
 304  * Return the number of free bytes in the sccb
 305  */
 306 int
 307 sclp_buffer_space(struct sclp_buffer *buffer)
 308 {
 309         int count;
 310
 311         count = MAX_SCCB_ROOM - buffer->sccb->header.length;
 312         if (buffer->current_line != NULL)
 313                 count -= sizeof(struct mto) + buffer->current_length;
 314         return count;
 315 }
 316
 317 /*
 318  * Return number of characters in buffer
 319  */
 320 int
 321 sclp_chars_in_buffer(struct sclp_buffer *buffer)
 322 {
 323         int count;
 324
 325         count = buffer->mto_char_sum;
 326         if (buffer->current_line != NULL)
 327                 count += buffer->current_length;
 328         return count;
 329 }
 330
 331 /*
 332  * sets or provides some values that influence the drivers behaviour
 333  */
 334 void
 335 sclp_set_columns(struct sclp_buffer *buffer, unsigned short columns)
 336 {
 337         buffer->columns = columns;
 338         if (buffer->current_line != NULL &&
 339             buffer->current_length > buffer->columns)
 340                 sclp_finalize_mto(buffer);
 341 }
 342
 343 void
 344 sclp_set_htab(struct sclp_buffer *buffer, unsigned short htab)
 345 {
 346         buffer->htab = htab;
 347 }
 348
 349 /*
 350  * called by sclp_console_init and/or sclp_tty_init
 351  */
 352 int
 353 sclp_rw_init(void)
 354 {
 355         static int init_done = 0;
 356         int rc;
 357
 358         if (init_done)
 359                 return 0;
 360
 361         rc = sclp_register(&sclp_rw_event);
 362         if (rc == 0)
 363                 init_done = 1;
 364         return rc;
 365 }
 366
 367 #define SCLP_BUFFER_MAX_RETRY           1
 368
 369 /*
 370  * second half of Write Event Data-function that has to be done after
 371  * interruption indicating completion of Service Call.
 372  */
 373 static void
 374 sclp_writedata_callback(struct sclp_req *request, void *data)
 375 {
 376         int rc;
 377         struct sclp_buffer *buffer;
 378         struct write_sccb *sccb;
 379
 380         buffer = (struct sclp_buffer *) data;
 381         sccb = buffer->sccb;
 382
 383         if (request->status == SCLP_REQ_FAILED) {
 384                 if (buffer->callback != NULL)
 385                         buffer->callback(buffer, -EIO);
 386                 return;
 387         }
 388         /* check SCLP response code and choose suitable action  */
 389         switch (sccb->header.response_code) {
 390         case 0x0020 :
 391                 /* Normal completion, buffer processed, message(s) sent */
 392                 rc = 0;
 393                 break;
 394
 395         case 0x0340: /* Contained SCLP equipment check */
 396                 if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {
 397                         rc = -EIO;
 398                         break;
 399                 }
 400                 /* remove processed buffers and requeue rest */
 401                 if (sclp_remove_processed((struct sccb_header *) sccb) > 0) {
 402                         /* not all buffers were processed */
 403                         sccb->header.response_code = 0x0000;
 404                         buffer->request.status = SCLP_REQ_FILLED;
 405                         rc = sclp_add_request(request);
 406                         if (rc == 0)
 407                                 return;
 408                 } else
 409                         rc = 0;
 410                 break;
 411
 412         case 0x0040: /* SCLP equipment check */
 413         case 0x05f0: /* Target resource in improper state */
 414                 if (++buffer->retry_count > SCLP_BUFFER_MAX_RETRY) {
 415                         rc = -EIO;
 416                         break;
 417                 }
 418                 /* retry request */
 419                 sccb->header.response_code = 0x0000;
 420                 buffer->request.status = SCLP_REQ_FILLED;
 421                 rc = sclp_add_request(request);
 422                 if (rc == 0)
 423                         return;
 424                 break;
 425         default:
 426                 if (sccb->header.response_code == 0x71f0)
 427                         rc = -ENOMEM;
 428                 else
 429                         rc = -EINVAL;
 430                 break;
 431         }
 432         if (buffer->callback != NULL)
 433                 buffer->callback(buffer, rc);
 434 }
 435
 436 /*
 437  * Setup the request structure in the struct sclp_buffer to do SCLP Write
 438  * Event Data and pass the request to the core SCLP loop. Return zero on
 439  * success, non-zero otherwise.
 440  */
 441 int
 442 sclp_emit_buffer(struct sclp_buffer *buffer,
 443                  void (*callback)(struct sclp_buffer *, int))
 444 {
 445         struct write_sccb *sccb;
 446
 447         /* add current line if there is one */
 448         if (buffer->current_line != NULL)
 449                 sclp_finalize_mto(buffer);
 450
 451         /* Are there messages in the output buffer ? */
 452         if (buffer->mto_number == 0)
 453                 return -EIO;
 454
 455         sccb = buffer->sccb;
 456         if (sclp_rw_event.sclp_send_mask & EvTyp_Msg_Mask)
 457                 /* Use normal write message */
 458                 sccb->msg_buf.header.type = EvTyp_Msg;
 459         else if (sclp_rw_event.sclp_send_mask & EvTyp_PMsgCmd_Mask)
 460                 /* Use write priority message */
 461                 sccb->msg_buf.header.type = EvTyp_PMsgCmd;
 462         else
 463                 return -ENOSYS;
 464         buffer->request.command = SCLP_CMDW_WRITEDATA;
 465         buffer->request.status = SCLP_REQ_FILLED;
 466         buffer->request.callback = sclp_writedata_callback;
 467         buffer->request.callback_data = buffer;
 468         buffer->request.sccb = sccb;
 469         buffer->callback = callback;
 470         return sclp_add_request(&buffer->request);
 471 }