drivers/s390/char/tape_char.c

   1 /*
   2  *  drivers/s390/char/tape_char.c
   3  *    character device frontend for tape device driver
   4  *
   5  *  S390 and zSeries version
   6  *    Copyright (C) 2001,2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
   7  *    Author(s): Carsten Otte <cotte@de.ibm.com>
   8  *               Michael Holzheu <holzheu@de.ibm.com>
   9  *               Tuan Ngo-Anh <ngoanh@de.ibm.com>
  10  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16 #include <linux/proc_fs.h>
  17 #include <linux/mtio.h>
  18
  19 #include <asm/uaccess.h>
  20
  21 #define TAPE_DBF_AREA   tape_core_dbf
  22
  23 #include "tape.h"
  24 #include "tape_std.h"
  25 #include "tape_class.h"
  26
  27 #define PRINTK_HEADER "TAPE_CHAR: "
  28
  29 #define TAPECHAR_MAJOR          0       /* get dynamic major */
  30
  31 /*
  32  * file operation structure for tape character frontend
  33  */
  34 static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
  35 static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
  36 static int tapechar_open(struct inode *,struct file *);
  37 static int tapechar_release(struct inode *,struct file *);
  38 static int tapechar_ioctl(struct inode *, struct file *, unsigned int,
  39                           unsigned long);
  40
  41 static struct file_operations tape_fops =
  42 {
  43         .owner = THIS_MODULE,
  44         .read = tapechar_read,
  45         .write = tapechar_write,
  46         .ioctl = tapechar_ioctl,
  47         .open = tapechar_open,
  48         .release = tapechar_release,
  49 };
  50
  51 static int tapechar_major = TAPECHAR_MAJOR;
  52
  53 /*
  54  * This function is called for every new tapedevice
  55  */
  56 int
  57 tapechar_setup_device(struct tape_device * device)
  58 {
  59         char    device_name[20];
  60
  61         sprintf(device_name, "ntibm%i", device->first_minor / 2);
  62         device->nt = register_tape_dev(
  63                 &device->cdev->dev,
  64                 MKDEV(tapechar_major, device->first_minor),
  65                 &tape_fops,
  66                 device_name,
  67                 "non-rewinding"
  68         );
  69         device_name[0] = 'r';
  70         device->rt = register_tape_dev(
  71                 &device->cdev->dev,
  72                 MKDEV(tapechar_major, device->first_minor + 1),
  73                 &tape_fops,
  74                 device_name,
  75                 "rewinding"
  76         );
  77
  78         return 0;
  79 }
  80
  81 void
  82 tapechar_cleanup_device(struct tape_device *device)
  83 {
  84         unregister_tape_dev(device->rt);
  85         device->rt = NULL;
  86         unregister_tape_dev(device->nt);
  87         device->nt = NULL;
  88 }
  89
  90 /*
  91  * Terminate write command (we write two TMs and skip backward over last)
  92  * This ensures that the tape is always correctly terminated.
  93  * When the user writes afterwards a new file, he will overwrite the
  94  * second TM and therefore one TM will remain to separate the
  95  * two files on the tape...
  96  */
  97 static inline void
  98 tapechar_terminate_write(struct tape_device *device)
  99 {
 100         if (tape_mtop(device, MTWEOF, 1) == 0 &&
 101             tape_mtop(device, MTWEOF, 1) == 0)
 102                 tape_mtop(device, MTBSR, 1);
 103 }
 104
 105 static inline int
 106 tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
 107 {
 108         struct idal_buffer *new;
 109
 110         if (device->char_data.idal_buf != NULL &&
 111             device->char_data.idal_buf->size == block_size)
 112                 return 0;
 113
 114         if (block_size > MAX_BLOCKSIZE) {
 115                 DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
 116                         block_size, MAX_BLOCKSIZE);
 117                 PRINT_ERR("Invalid blocksize (%zd> %d)\n",
 118                         block_size, MAX_BLOCKSIZE);
 119                 return -EINVAL;
 120         }
 121
 122         /* The current idal buffer is not correct. Allocate a new one. */
 123         new = idal_buffer_alloc(block_size, 0);
 124         if (new == NULL)
 125                 return -ENOMEM;
 126
 127         if (device->char_data.idal_buf != NULL)
 128                 idal_buffer_free(device->char_data.idal_buf);
 129
 130         device->char_data.idal_buf = new;
 131
 132         return 0;
 133 }
 134
 135 /*
 136  * Tape device read function
 137  */
 138 ssize_t
 139 tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
 140 {
 141         struct tape_device *device;
 142         struct tape_request *request;
 143         size_t block_size;
 144         int rc;
 145
 146         DBF_EVENT(6, "TCHAR:read\n");
 147         device = (struct tape_device *) filp->private_data;
 148
 149         /*
 150          * If the tape isn't terminated yet, do it now. And since we then
 151          * are at the end of the tape there wouldn't be anything to read
 152          * anyways. So we return immediatly.
 153          */
 154         if(device->required_tapemarks) {
 155                 return tape_std_terminate_write(device);
 156         }
 157
 158         /* Find out block size to use */
 159         if (device->char_data.block_size != 0) {
 160                 if (count < device->char_data.block_size) {
 161                         DBF_EVENT(3, "TCHAR:read smaller than block "
 162                                   "size was requested\n");
 163                         return -EINVAL;
 164                 }
 165                 block_size = device->char_data.block_size;
 166         } else {
 167                 block_size = count;
 168         }
 169
 170         rc = tapechar_check_idalbuffer(device, block_size);
 171         if (rc)
 172                 return rc;
 173
 174 #ifdef CONFIG_S390_TAPE_BLOCK
 175         /* Changes position. */
 176         device->blk_data.medium_changed = 1;
 177 #endif
 178
 179         DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
 180         /* Let the discipline build the ccw chain. */
 181         request = device->discipline->read_block(device, block_size);
 182         if (IS_ERR(request))
 183                 return PTR_ERR(request);
 184         /* Execute it. */
 185         rc = tape_do_io(device, request);
 186         if (rc == 0) {
 187                 rc = block_size - request->rescnt;
 188                 DBF_EVENT(6, "TCHAR:rbytes:  %x\n", rc);
 189                 filp->f_pos += rc;
 190                 /* Copy data from idal buffer to user space. */
 191                 if (idal_buffer_to_user(device->char_data.idal_buf,
 192                                         data, rc) != 0)
 193                         rc = -EFAULT;
 194         }
 195         tape_free_request(request);
 196         return rc;
 197 }
 198
 199 /*
 200  * Tape device write function
 201  */
 202 ssize_t
 203 tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
 204 {
 205         struct tape_device *device;
 206         struct tape_request *request;
 207         size_t block_size;
 208         size_t written;
 209         int nblocks;
 210         int i, rc;
 211
 212         DBF_EVENT(6, "TCHAR:write\n");
 213         device = (struct tape_device *) filp->private_data;
 214         /* Find out block size and number of blocks */
 215         if (device->char_data.block_size != 0) {
 216                 if (count < device->char_data.block_size) {
 217                         DBF_EVENT(3, "TCHAR:write smaller than block "
 218                                   "size was requested\n");
 219                         return -EINVAL;
 220                 }
 221                 block_size = device->char_data.block_size;
 222                 nblocks = count / block_size;
 223         } else {
 224                 block_size = count;
 225                 nblocks = 1;
 226         }
 227
 228         rc = tapechar_check_idalbuffer(device, block_size);
 229         if (rc)
 230                 return rc;
 231
 232 #ifdef CONFIG_S390_TAPE_BLOCK
 233         /* Changes position. */
 234         device->blk_data.medium_changed = 1;
 235 #endif
 236
 237         DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
 238         DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
 239         /* Let the discipline build the ccw chain. */
 240         request = device->discipline->write_block(device, block_size);
 241         if (IS_ERR(request))
 242                 return PTR_ERR(request);
 243         rc = 0;
 244         written = 0;
 245         for (i = 0; i < nblocks; i++) {
 246                 /* Copy data from user space to idal buffer. */
 247                 if (idal_buffer_from_user(device->char_data.idal_buf,
 248                                           data, block_size)) {
 249                         rc = -EFAULT;
 250                         break;
 251                 }
 252                 rc = tape_do_io(device, request);
 253                 if (rc)
 254                         break;
 255                 DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
 256                           block_size - request->rescnt);
 257                 filp->f_pos += block_size - request->rescnt;
 258                 written += block_size - request->rescnt;
 259                 if (request->rescnt != 0)
 260                         break;
 261                 data += block_size;
 262         }
 263         tape_free_request(request);
 264         if (rc == -ENOSPC) {
 265                 /*
 266                  * Ok, the device has no more space. It has NOT written
 267                  * the block.
 268                  */
 269                 if (device->discipline->process_eov)
 270                         device->discipline->process_eov(device);
 271                 if (written > 0)
 272                         rc = 0;
 273
 274         }
 275
 276         /*
 277          * After doing a write we always need two tapemarks to correctly
 278          * terminate the tape (one to terminate the file, the second to
 279          * flag the end of recorded data.
 280          * Since process_eov positions the tape in front of the written
 281          * tapemark it doesn't hurt to write two marks again.
 282          */
 283         if (!rc)
 284                 device->required_tapemarks = 2;
 285
 286         return rc ? rc : written;
 287 }
 288
 289 /*
 290  * Character frontend tape device open function.
 291  */
 292 int
 293 tapechar_open (struct inode *inode, struct file *filp)
 294 {
 295         struct tape_device *device;
 296         int minor, rc;
 297
 298         DBF_EVENT(6, "TCHAR:open: %i:%i\n",
 299                 imajor(filp->f_dentry->d_inode),
 300                 iminor(filp->f_dentry->d_inode));
 301
 302         if (imajor(filp->f_dentry->d_inode) != tapechar_major)
 303                 return -ENODEV;
 304
 305         minor = iminor(filp->f_dentry->d_inode);
 306         device = tape_get_device(minor / TAPE_MINORS_PER_DEV);
 307         if (IS_ERR(device)) {
 308                 DBF_EVENT(3, "TCHAR:open: tape_get_device() failed\n");
 309                 return PTR_ERR(device);
 310         }
 311
 312
 313         rc = tape_open(device);
 314         if (rc == 0) {
 315                 filp->private_data = device;
 316                 return nonseekable_open(inode, filp);
 317         }
 318         tape_put_device(device);
 319
 320         return rc;
 321 }
 322
 323 /*
 324  * Character frontend tape device release function.
 325  */
 326
 327 int
 328 tapechar_release(struct inode *inode, struct file *filp)
 329 {
 330         struct tape_device *device;
 331
 332         DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
 333         device = (struct tape_device *) filp->private_data;
 334
 335         /*
 336          * If this is the rewinding tape minor then rewind. In that case we
 337          * write all required tapemarks. Otherwise only one to terminate the
 338          * file.
 339          */
 340         if ((iminor(inode) & 1) != 0) {
 341                 if (device->required_tapemarks)
 342                         tape_std_terminate_write(device);
 343                 tape_mtop(device, MTREW, 1);
 344         } else {
 345                 if (device->required_tapemarks > 1) {
 346                         if (tape_mtop(device, MTWEOF, 1) == 0)
 347                                 device->required_tapemarks--;
 348                 }
 349         }
 350
 351         if (device->char_data.idal_buf != NULL) {
 352                 idal_buffer_free(device->char_data.idal_buf);
 353                 device->char_data.idal_buf = NULL;
 354         }
 355         tape_release(device);
 356         filp->private_data = tape_put_device(device);
 357
 358         return 0;
 359 }
 360
 361 /*
 362  * Tape device io controls.
 363  */
 364 static int
 365 tapechar_ioctl(struct inode *inp, struct file *filp,
 366                unsigned int no, unsigned long data)
 367 {
 368         struct tape_device *device;
 369         int rc;
 370
 371         DBF_EVENT(6, "TCHAR:ioct\n");
 372
 373         device = (struct tape_device *) filp->private_data;
 374
 375         if (no == MTIOCTOP) {
 376                 struct mtop op;
 377
 378                 if (copy_from_user(&op, (char __user *) data, sizeof(op)) != 0)
 379                         return -EFAULT;
 380                 if (op.mt_count < 0)
 381                         return -EINVAL;
 382
 383                 /*
 384                  * Operations that change tape position should write final
 385                  * tapemarks.
 386                  */
 387                 switch (op.mt_op) {
 388                         case MTFSF:
 389                         case MTBSF:
 390                         case MTFSR:
 391                         case MTBSR:
 392                         case MTREW:
 393                         case MTOFFL:
 394                         case MTEOM:
 395                         case MTRETEN:
 396                         case MTBSFM:
 397                         case MTFSFM:
 398                         case MTSEEK:
 399 #ifdef CONFIG_S390_TAPE_BLOCK
 400                                 device->blk_data.medium_changed = 1;
 401 #endif
 402                                 if (device->required_tapemarks)
 403                                         tape_std_terminate_write(device);
 404                         default:
 405                                 ;
 406                 }
 407                 rc = tape_mtop(device, op.mt_op, op.mt_count);
 408
 409                 if (op.mt_op == MTWEOF && rc == 0) {
 410                         if (op.mt_count > device->required_tapemarks)
 411                                 device->required_tapemarks = 0;
 412                         else
 413                                 device->required_tapemarks -= op.mt_count;
 414                 }
 415                 return rc;
 416         }
 417         if (no == MTIOCPOS) {
 418                 /* MTIOCPOS: query the tape position. */
 419                 struct mtpos pos;
 420
 421                 rc = tape_mtop(device, MTTELL, 1);
 422                 if (rc < 0)
 423                         return rc;
 424                 pos.mt_blkno = rc;
 425                 if (copy_to_user((char __user *) data, &pos, sizeof(pos)) != 0)
 426                         return -EFAULT;
 427                 return 0;
 428         }
 429         if (no == MTIOCGET) {
 430                 /* MTIOCGET: query the tape drive status. */
 431                 struct mtget get;
 432
 433                 memset(&get, 0, sizeof(get));
 434                 get.mt_type = MT_ISUNKNOWN;
 435                 get.mt_resid = 0 /* device->devstat.rescnt */;
 436                 get.mt_dsreg = device->tape_state;
 437                 /* FIXME: mt_gstat, mt_erreg, mt_fileno */
 438                 get.mt_gstat = 0;
 439                 get.mt_erreg = 0;
 440                 get.mt_fileno = 0;
 441                 get.mt_gstat  = device->tape_generic_status;
 442
 443                 if (device->medium_state == MS_LOADED) {
 444                         rc = tape_mtop(device, MTTELL, 1);
 445
 446                         if (rc < 0)
 447                                 return rc;
 448
 449                         if (rc == 0)
 450                                 get.mt_gstat |= GMT_BOT(~0);
 451
 452                         get.mt_blkno = rc;
 453                 }
 454
 455                 if (copy_to_user((char __user *) data, &get, sizeof(get)) != 0)
 456                         return -EFAULT;
 457
 458                 return 0;
 459         }
 460         /* Try the discipline ioctl function. */
 461         if (device->discipline->ioctl_fn == NULL)
 462                 return -EINVAL;
 463         return device->discipline->ioctl_fn(device, no, data);
 464 }
 465
 466 /*
 467  * Initialize character device frontend.
 468  */
 469 int
 470 tapechar_init (void)
 471 {
 472         dev_t   dev;
 473
 474         if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
 475                 return -1;
 476
 477         tapechar_major = MAJOR(dev);
 478         PRINT_INFO("tape gets major %d for character devices\n", MAJOR(dev));
 479
 480         return 0;
 481 }
 482
 483 /*
 484  * cleanup
 485  */
 486 void
 487 tapechar_exit(void)
 488 {
 489         PRINT_INFO("tape releases major %d for character devices\n",
 490                 tapechar_major);
 491         unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
 492 }