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 IBM Corp. 2001,2006
   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/module.h>
  14 #include <linux/types.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/mtio.h>
  17 #include <linux/smp_lock.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 static long tapechar_compat_ioctl(struct file *, unsigned int,
  41                           unsigned long);
  42
  43 static const struct file_operations tape_fops =
  44 {
  45         .owner = THIS_MODULE,
  46         .read = tapechar_read,
  47         .write = tapechar_write,
  48         .ioctl = tapechar_ioctl,
  49         .compat_ioctl = tapechar_compat_ioctl,
  50         .open = tapechar_open,
  51         .release = tapechar_release,
  52 };
  53
  54 static int tapechar_major = TAPECHAR_MAJOR;
  55
  56 /*
  57  * This function is called for every new tapedevice
  58  */
  59 int
  60 tapechar_setup_device(struct tape_device * device)
  61 {
  62         char    device_name[20];
  63
  64         sprintf(device_name, "ntibm%i", device->first_minor / 2);
  65         device->nt = register_tape_dev(
  66                 &device->cdev->dev,
  67                 MKDEV(tapechar_major, device->first_minor),
  68                 &tape_fops,
  69                 device_name,
  70                 "non-rewinding"
  71         );
  72         device_name[0] = 'r';
  73         device->rt = register_tape_dev(
  74                 &device->cdev->dev,
  75                 MKDEV(tapechar_major, device->first_minor + 1),
  76                 &tape_fops,
  77                 device_name,
  78                 "rewinding"
  79         );
  80
  81         return 0;
  82 }
  83
  84 void
  85 tapechar_cleanup_device(struct tape_device *device)
  86 {
  87         unregister_tape_dev(&device->cdev->dev, device->rt);
  88         device->rt = NULL;
  89         unregister_tape_dev(&device->cdev->dev, device->nt);
  90         device->nt = NULL;
  91 }
  92
  93 static int
  94 tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
  95 {
  96         struct idal_buffer *new;
  97
  98         if (device->char_data.idal_buf != NULL &&
  99             device->char_data.idal_buf->size == block_size)
 100                 return 0;
 101
 102         if (block_size > MAX_BLOCKSIZE) {
 103                 DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
 104                         block_size, MAX_BLOCKSIZE);
 105                 PRINT_ERR("Invalid blocksize (%zd> %d)\n",
 106                         block_size, MAX_BLOCKSIZE);
 107                 return -EINVAL;
 108         }
 109
 110         /* The current idal buffer is not correct. Allocate a new one. */
 111         new = idal_buffer_alloc(block_size, 0);
 112         if (new == NULL)
 113                 return -ENOMEM;
 114
 115         if (device->char_data.idal_buf != NULL)
 116                 idal_buffer_free(device->char_data.idal_buf);
 117
 118         device->char_data.idal_buf = new;
 119
 120         return 0;
 121 }
 122
 123 /*
 124  * Tape device read function
 125  */
 126 static ssize_t
 127 tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
 128 {
 129         struct tape_device *device;
 130         struct tape_request *request;
 131         size_t block_size;
 132         int rc;
 133
 134         DBF_EVENT(6, "TCHAR:read\n");
 135         device = (struct tape_device *) filp->private_data;
 136
 137         /*
 138          * If the tape isn't terminated yet, do it now. And since we then
 139          * are at the end of the tape there wouldn't be anything to read
 140          * anyways. So we return immediatly.
 141          */
 142         if(device->required_tapemarks) {
 143                 return tape_std_terminate_write(device);
 144         }
 145
 146         /* Find out block size to use */
 147         if (device->char_data.block_size != 0) {
 148                 if (count < device->char_data.block_size) {
 149                         DBF_EVENT(3, "TCHAR:read smaller than block "
 150                                   "size was requested\n");
 151                         return -EINVAL;
 152                 }
 153                 block_size = device->char_data.block_size;
 154         } else {
 155                 block_size = count;
 156         }
 157
 158         rc = tapechar_check_idalbuffer(device, block_size);
 159         if (rc)
 160                 return rc;
 161
 162 #ifdef CONFIG_S390_TAPE_BLOCK
 163         /* Changes position. */
 164         device->blk_data.medium_changed = 1;
 165 #endif
 166
 167         DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
 168         /* Let the discipline build the ccw chain. */
 169         request = device->discipline->read_block(device, block_size);
 170         if (IS_ERR(request))
 171                 return PTR_ERR(request);
 172         /* Execute it. */
 173         rc = tape_do_io(device, request);
 174         if (rc == 0) {
 175                 rc = block_size - request->rescnt;
 176                 DBF_EVENT(6, "TCHAR:rbytes:  %x\n", rc);
 177                 filp->f_pos += rc;
 178                 /* Copy data from idal buffer to user space. */
 179                 if (idal_buffer_to_user(device->char_data.idal_buf,
 180                                         data, rc) != 0)
 181                         rc = -EFAULT;
 182         }
 183         tape_free_request(request);
 184         return rc;
 185 }
 186
 187 /*
 188  * Tape device write function
 189  */
 190 static ssize_t
 191 tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
 192 {
 193         struct tape_device *device;
 194         struct tape_request *request;
 195         size_t block_size;
 196         size_t written;
 197         int nblocks;
 198         int i, rc;
 199
 200         DBF_EVENT(6, "TCHAR:write\n");
 201         device = (struct tape_device *) filp->private_data;
 202         /* Find out block size and number of blocks */
 203         if (device->char_data.block_size != 0) {
 204                 if (count < device->char_data.block_size) {
 205                         DBF_EVENT(3, "TCHAR:write smaller than block "
 206                                   "size was requested\n");
 207                         return -EINVAL;
 208                 }
 209                 block_size = device->char_data.block_size;
 210                 nblocks = count / block_size;
 211         } else {
 212                 block_size = count;
 213                 nblocks = 1;
 214         }
 215
 216         rc = tapechar_check_idalbuffer(device, block_size);
 217         if (rc)
 218                 return rc;
 219
 220 #ifdef CONFIG_S390_TAPE_BLOCK
 221         /* Changes position. */
 222         device->blk_data.medium_changed = 1;
 223 #endif
 224
 225         DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
 226         DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
 227         /* Let the discipline build the ccw chain. */
 228         request = device->discipline->write_block(device, block_size);
 229         if (IS_ERR(request))
 230                 return PTR_ERR(request);
 231         rc = 0;
 232         written = 0;
 233         for (i = 0; i < nblocks; i++) {
 234                 /* Copy data from user space to idal buffer. */
 235                 if (idal_buffer_from_user(device->char_data.idal_buf,
 236                                           data, block_size)) {
 237                         rc = -EFAULT;
 238                         break;
 239                 }
 240                 rc = tape_do_io(device, request);
 241                 if (rc)
 242                         break;
 243                 DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
 244                           block_size - request->rescnt);
 245                 filp->f_pos += block_size - request->rescnt;
 246                 written += block_size - request->rescnt;
 247                 if (request->rescnt != 0)
 248                         break;
 249                 data += block_size;
 250         }
 251         tape_free_request(request);
 252         if (rc == -ENOSPC) {
 253                 /*
 254                  * Ok, the device has no more space. It has NOT written
 255                  * the block.
 256                  */
 257                 if (device->discipline->process_eov)
 258                         device->discipline->process_eov(device);
 259                 if (written > 0)
 260                         rc = 0;
 261
 262         }
 263
 264         /*
 265          * After doing a write we always need two tapemarks to correctly
 266          * terminate the tape (one to terminate the file, the second to
 267          * flag the end of recorded data.
 268          * Since process_eov positions the tape in front of the written
 269          * tapemark it doesn't hurt to write two marks again.
 270          */
 271         if (!rc)
 272                 device->required_tapemarks = 2;
 273
 274         return rc ? rc : written;
 275 }
 276
 277 /*
 278  * Character frontend tape device open function.
 279  */
 280 static int
 281 tapechar_open (struct inode *inode, struct file *filp)
 282 {
 283         struct tape_device *device;
 284         int minor, rc;
 285
 286         DBF_EVENT(6, "TCHAR:open: %i:%i\n",
 287                 imajor(filp->f_path.dentry->d_inode),
 288                 iminor(filp->f_path.dentry->d_inode));
 289
 290         if (imajor(filp->f_path.dentry->d_inode) != tapechar_major)
 291                 return -ENODEV;
 292
 293         lock_kernel();
 294         minor = iminor(filp->f_path.dentry->d_inode);
 295         device = tape_get_device(minor / TAPE_MINORS_PER_DEV);
 296         if (IS_ERR(device)) {
 297                 DBF_EVENT(3, "TCHAR:open: tape_get_device() failed\n");
 298                 rc = PTR_ERR(device);
 299                 goto out;
 300         }
 301
 302
 303         rc = tape_open(device);
 304         if (rc == 0) {
 305                 filp->private_data = device;
 306                 rc = nonseekable_open(inode, filp);
 307         }
 308         else
 309                 tape_put_device(device);
 310
 311 out:
 312         unlock_kernel();
 313         return rc;
 314 }
 315
 316 /*
 317  * Character frontend tape device release function.
 318  */
 319
 320 static int
 321 tapechar_release(struct inode *inode, struct file *filp)
 322 {
 323         struct tape_device *device;
 324
 325         DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
 326         device = (struct tape_device *) filp->private_data;
 327
 328         /*
 329          * If this is the rewinding tape minor then rewind. In that case we
 330          * write all required tapemarks. Otherwise only one to terminate the
 331          * file.
 332          */
 333         if ((iminor(inode) & 1) != 0) {
 334                 if (device->required_tapemarks)
 335                         tape_std_terminate_write(device);
 336                 tape_mtop(device, MTREW, 1);
 337         } else {
 338                 if (device->required_tapemarks > 1) {
 339                         if (tape_mtop(device, MTWEOF, 1) == 0)
 340                                 device->required_tapemarks--;
 341                 }
 342         }
 343
 344         if (device->char_data.idal_buf != NULL) {
 345                 idal_buffer_free(device->char_data.idal_buf);
 346                 device->char_data.idal_buf = NULL;
 347         }
 348         tape_release(device);
 349         filp->private_data = tape_put_device(device);
 350
 351         return 0;
 352 }
 353
 354 /*
 355  * Tape device io controls.
 356  */
 357 static int
 358 tapechar_ioctl(struct inode *inp, struct file *filp,
 359                unsigned int no, unsigned long data)
 360 {
 361         struct tape_device *device;
 362         int rc;
 363
 364         DBF_EVENT(6, "TCHAR:ioct\n");
 365
 366         device = (struct tape_device *) filp->private_data;
 367
 368         if (no == MTIOCTOP) {
 369                 struct mtop op;
 370
 371                 if (copy_from_user(&op, (char __user *) data, sizeof(op)) != 0)
 372                         return -EFAULT;
 373                 if (op.mt_count < 0)
 374                         return -EINVAL;
 375
 376                 /*
 377                  * Operations that change tape position should write final
 378                  * tapemarks.
 379                  */
 380                 switch (op.mt_op) {
 381                         case MTFSF:
 382                         case MTBSF:
 383                         case MTFSR:
 384                         case MTBSR:
 385                         case MTREW:
 386                         case MTOFFL:
 387                         case MTEOM:
 388                         case MTRETEN:
 389                         case MTBSFM:
 390                         case MTFSFM:
 391                         case MTSEEK:
 392 #ifdef CONFIG_S390_TAPE_BLOCK
 393                                 device->blk_data.medium_changed = 1;
 394 #endif
 395                                 if (device->required_tapemarks)
 396                                         tape_std_terminate_write(device);
 397                         default:
 398                                 ;
 399                 }
 400                 rc = tape_mtop(device, op.mt_op, op.mt_count);
 401
 402                 if (op.mt_op == MTWEOF && rc == 0) {
 403                         if (op.mt_count > device->required_tapemarks)
 404                                 device->required_tapemarks = 0;
 405                         else
 406                                 device->required_tapemarks -= op.mt_count;
 407                 }
 408                 return rc;
 409         }
 410         if (no == MTIOCPOS) {
 411                 /* MTIOCPOS: query the tape position. */
 412                 struct mtpos pos;
 413
 414                 rc = tape_mtop(device, MTTELL, 1);
 415                 if (rc < 0)
 416                         return rc;
 417                 pos.mt_blkno = rc;
 418                 if (copy_to_user((char __user *) data, &pos, sizeof(pos)) != 0)
 419                         return -EFAULT;
 420                 return 0;
 421         }
 422         if (no == MTIOCGET) {
 423                 /* MTIOCGET: query the tape drive status. */
 424                 struct mtget get;
 425
 426                 memset(&get, 0, sizeof(get));
 427                 get.mt_type = MT_ISUNKNOWN;
 428                 get.mt_resid = 0 /* device->devstat.rescnt */;
 429                 get.mt_dsreg = device->tape_state;
 430                 /* FIXME: mt_gstat, mt_erreg, mt_fileno */
 431                 get.mt_gstat = 0;
 432                 get.mt_erreg = 0;
 433                 get.mt_fileno = 0;
 434                 get.mt_gstat  = device->tape_generic_status;
 435
 436                 if (device->medium_state == MS_LOADED) {
 437                         rc = tape_mtop(device, MTTELL, 1);
 438
 439                         if (rc < 0)
 440                                 return rc;
 441
 442                         if (rc == 0)
 443                                 get.mt_gstat |= GMT_BOT(~0);
 444
 445                         get.mt_blkno = rc;
 446                 }
 447
 448                 if (copy_to_user((char __user *) data, &get, sizeof(get)) != 0)
 449                         return -EFAULT;
 450
 451                 return 0;
 452         }
 453         /* Try the discipline ioctl function. */
 454         if (device->discipline->ioctl_fn == NULL)
 455                 return -EINVAL;
 456         return device->discipline->ioctl_fn(device, no, data);
 457 }
 458
 459 static long
 460 tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
 461 {
 462         struct tape_device *device = filp->private_data;
 463         int rval = -ENOIOCTLCMD;
 464
 465         if (device->discipline->ioctl_fn) {
 466                 lock_kernel();
 467                 rval = device->discipline->ioctl_fn(device, no, data);
 468                 unlock_kernel();
 469                 if (rval == -EINVAL)
 470                         rval = -ENOIOCTLCMD;
 471         }
 472
 473         return rval;
 474 }
 475
 476 /*
 477  * Initialize character device frontend.
 478  */
 479 int
 480 tapechar_init (void)
 481 {
 482         dev_t   dev;
 483
 484         if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
 485                 return -1;
 486
 487         tapechar_major = MAJOR(dev);
 488         PRINT_INFO("tape gets major %d for character devices\n", MAJOR(dev));
 489
 490         return 0;
 491 }
 492
 493 /*
 494  * cleanup
 495  */
 496 void
 497 tapechar_exit(void)
 498 {
 499         PRINT_INFO("tape releases major %d for character devices\n",
 500                 tapechar_major);
 501         unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
 502 }