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 TAPECHAR_MAJOR          0       /* get dynamic major */
  28
  29 /*
  30  * file operation structure for tape character frontend
  31  */
  32 static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
  33 static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
  34 static int tapechar_open(struct inode *,struct file *);
  35 static int tapechar_release(struct inode *,struct file *);
  36 static int tapechar_ioctl(struct inode *, struct file *, unsigned int,
  37                           unsigned long);
  38 static long tapechar_compat_ioctl(struct file *, unsigned int,
  39                           unsigned long);
  40
  41 static const struct file_operations tape_fops =
  42 {
  43         .owner = THIS_MODULE,
  44         .read = tapechar_read,
  45         .write = tapechar_write,
  46         .ioctl = tapechar_ioctl,
  47         .compat_ioctl = tapechar_compat_ioctl,
  48         .open = tapechar_open,
  49         .release = tapechar_release,
  50 };
  51
  52 static int tapechar_major = TAPECHAR_MAJOR;
  53
  54 /*
  55  * This function is called for every new tapedevice
  56  */
  57 int
  58 tapechar_setup_device(struct tape_device * device)
  59 {
  60         char    device_name[20];
  61
  62         sprintf(device_name, "ntibm%i", device->first_minor / 2);
  63         device->nt = register_tape_dev(
  64                 &device->cdev->dev,
  65                 MKDEV(tapechar_major, device->first_minor),
  66                 &tape_fops,
  67                 device_name,
  68                 "non-rewinding"
  69         );
  70         device_name[0] = 'r';
  71         device->rt = register_tape_dev(
  72                 &device->cdev->dev,
  73                 MKDEV(tapechar_major, device->first_minor + 1),
  74                 &tape_fops,
  75                 device_name,
  76                 "rewinding"
  77         );
  78
  79         return 0;
  80 }
  81
  82 void
  83 tapechar_cleanup_device(struct tape_device *device)
  84 {
  85         unregister_tape_dev(&device->cdev->dev, device->rt);
  86         device->rt = NULL;
  87         unregister_tape_dev(&device->cdev->dev, device->nt);
  88         device->nt = NULL;
  89 }
  90
  91 static int
  92 tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
  93 {
  94         struct idal_buffer *new;
  95
  96         if (device->char_data.idal_buf != NULL &&
  97             device->char_data.idal_buf->size == block_size)
  98                 return 0;
  99
 100         if (block_size > MAX_BLOCKSIZE) {
 101                 DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
 102                         block_size, MAX_BLOCKSIZE);
 103                 return -EINVAL;
 104         }
 105
 106         /* The current idal buffer is not correct. Allocate a new one. */
 107         new = idal_buffer_alloc(block_size, 0);
 108         if (IS_ERR(new))
 109                 return -ENOMEM;
 110
 111         if (device->char_data.idal_buf != NULL)
 112                 idal_buffer_free(device->char_data.idal_buf);
 113
 114         device->char_data.idal_buf = new;
 115
 116         return 0;
 117 }
 118
 119 /*
 120  * Tape device read function
 121  */
 122 static ssize_t
 123 tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
 124 {
 125         struct tape_device *device;
 126         struct tape_request *request;
 127         size_t block_size;
 128         int rc;
 129
 130         DBF_EVENT(6, "TCHAR:read\n");
 131         device = (struct tape_device *) filp->private_data;
 132
 133         /*
 134          * If the tape isn't terminated yet, do it now. And since we then
 135          * are at the end of the tape there wouldn't be anything to read
 136          * anyways. So we return immediatly.
 137          */
 138         if(device->required_tapemarks) {
 139                 return tape_std_terminate_write(device);
 140         }
 141
 142         /* Find out block size to use */
 143         if (device->char_data.block_size != 0) {
 144                 if (count < device->char_data.block_size) {
 145                         DBF_EVENT(3, "TCHAR:read smaller than block "
 146                                   "size was requested\n");
 147                         return -EINVAL;
 148                 }
 149                 block_size = device->char_data.block_size;
 150         } else {
 151                 block_size = count;
 152         }
 153
 154         rc = tapechar_check_idalbuffer(device, block_size);
 155         if (rc)
 156                 return rc;
 157
 158 #ifdef CONFIG_S390_TAPE_BLOCK
 159         /* Changes position. */
 160         device->blk_data.medium_changed = 1;
 161 #endif
 162
 163         DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
 164         /* Let the discipline build the ccw chain. */
 165         request = device->discipline->read_block(device, block_size);
 166         if (IS_ERR(request))
 167                 return PTR_ERR(request);
 168         /* Execute it. */
 169         rc = tape_do_io(device, request);
 170         if (rc == 0) {
 171                 rc = block_size - request->rescnt;
 172                 DBF_EVENT(6, "TCHAR:rbytes:  %x\n", rc);
 173                 /* Copy data from idal buffer to user space. */
 174                 if (idal_buffer_to_user(device->char_data.idal_buf,
 175                                         data, rc) != 0)
 176                         rc = -EFAULT;
 177         }
 178         tape_free_request(request);
 179         return rc;
 180 }
 181
 182 /*
 183  * Tape device write function
 184  */
 185 static ssize_t
 186 tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
 187 {
 188         struct tape_device *device;
 189         struct tape_request *request;
 190         size_t block_size;
 191         size_t written;
 192         int nblocks;
 193         int i, rc;
 194
 195         DBF_EVENT(6, "TCHAR:write\n");
 196         device = (struct tape_device *) filp->private_data;
 197         /* Find out block size and number of blocks */
 198         if (device->char_data.block_size != 0) {
 199                 if (count < device->char_data.block_size) {
 200                         DBF_EVENT(3, "TCHAR:write smaller than block "
 201                                   "size was requested\n");
 202                         return -EINVAL;
 203                 }
 204                 block_size = device->char_data.block_size;
 205                 nblocks = count / block_size;
 206         } else {
 207                 block_size = count;
 208                 nblocks = 1;
 209         }
 210
 211         rc = tapechar_check_idalbuffer(device, block_size);
 212         if (rc)
 213                 return rc;
 214
 215 #ifdef CONFIG_S390_TAPE_BLOCK
 216         /* Changes position. */
 217         device->blk_data.medium_changed = 1;
 218 #endif
 219
 220         DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
 221         DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
 222         /* Let the discipline build the ccw chain. */
 223         request = device->discipline->write_block(device, block_size);
 224         if (IS_ERR(request))
 225                 return PTR_ERR(request);
 226         rc = 0;
 227         written = 0;
 228         for (i = 0; i < nblocks; i++) {
 229                 /* Copy data from user space to idal buffer. */
 230                 if (idal_buffer_from_user(device->char_data.idal_buf,
 231                                           data, block_size)) {
 232                         rc = -EFAULT;
 233                         break;
 234                 }
 235                 rc = tape_do_io(device, request);
 236                 if (rc)
 237                         break;
 238                 DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
 239                           block_size - request->rescnt);
 240                 written += block_size - request->rescnt;
 241                 if (request->rescnt != 0)
 242                         break;
 243                 data += block_size;
 244         }
 245         tape_free_request(request);
 246         if (rc == -ENOSPC) {
 247                 /*
 248                  * Ok, the device has no more space. It has NOT written
 249                  * the block.
 250                  */
 251                 if (device->discipline->process_eov)
 252                         device->discipline->process_eov(device);
 253                 if (written > 0)
 254                         rc = 0;
 255
 256         }
 257
 258         /*
 259          * After doing a write we always need two tapemarks to correctly
 260          * terminate the tape (one to terminate the file, the second to
 261          * flag the end of recorded data.
 262          * Since process_eov positions the tape in front of the written
 263          * tapemark it doesn't hurt to write two marks again.
 264          */
 265         if (!rc)
 266                 device->required_tapemarks = 2;
 267
 268         return rc ? rc : written;
 269 }
 270
 271 /*
 272  * Character frontend tape device open function.
 273  */
 274 static int
 275 tapechar_open (struct inode *inode, struct file *filp)
 276 {
 277         struct tape_device *device;
 278         int minor, rc;
 279
 280         DBF_EVENT(6, "TCHAR:open: %i:%i\n",
 281                 imajor(filp->f_path.dentry->d_inode),
 282                 iminor(filp->f_path.dentry->d_inode));
 283
 284         if (imajor(filp->f_path.dentry->d_inode) != tapechar_major)
 285                 return -ENODEV;
 286
 287         lock_kernel();
 288         minor = iminor(filp->f_path.dentry->d_inode);
 289         device = tape_get_device(minor / TAPE_MINORS_PER_DEV);
 290         if (IS_ERR(device)) {
 291                 DBF_EVENT(3, "TCHAR:open: tape_get_device() failed\n");
 292                 rc = PTR_ERR(device);
 293                 goto out;
 294         }
 295
 296
 297         rc = tape_open(device);
 298         if (rc == 0) {
 299                 filp->private_data = device;
 300                 rc = nonseekable_open(inode, filp);
 301         }
 302         else
 303                 tape_put_device(device);
 304
 305 out:
 306         unlock_kernel();
 307         return rc;
 308 }
 309
 310 /*
 311  * Character frontend tape device release function.
 312  */
 313
 314 static int
 315 tapechar_release(struct inode *inode, struct file *filp)
 316 {
 317         struct tape_device *device;
 318
 319         DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
 320         device = (struct tape_device *) filp->private_data;
 321
 322         /*
 323          * If this is the rewinding tape minor then rewind. In that case we
 324          * write all required tapemarks. Otherwise only one to terminate the
 325          * file.
 326          */
 327         if ((iminor(inode) & 1) != 0) {
 328                 if (device->required_tapemarks)
 329                         tape_std_terminate_write(device);
 330                 tape_mtop(device, MTREW, 1);
 331         } else {
 332                 if (device->required_tapemarks > 1) {
 333                         if (tape_mtop(device, MTWEOF, 1) == 0)
 334                                 device->required_tapemarks--;
 335                 }
 336         }
 337
 338         if (device->char_data.idal_buf != NULL) {
 339                 idal_buffer_free(device->char_data.idal_buf);
 340                 device->char_data.idal_buf = NULL;
 341         }
 342         tape_release(device);
 343         filp->private_data = tape_put_device(device);
 344
 345         return 0;
 346 }
 347
 348 /*
 349  * Tape device io controls.
 350  */
 351 static int
 352 tapechar_ioctl(struct inode *inp, struct file *filp,
 353                unsigned int no, unsigned long data)
 354 {
 355         struct tape_device *device;
 356         int rc;
 357
 358         DBF_EVENT(6, "TCHAR:ioct\n");
 359
 360         device = (struct tape_device *) filp->private_data;
 361
 362         if (no == MTIOCTOP) {
 363                 struct mtop op;
 364
 365                 if (copy_from_user(&op, (char __user *) data, sizeof(op)) != 0)
 366                         return -EFAULT;
 367                 if (op.mt_count < 0)
 368                         return -EINVAL;
 369
 370                 /*
 371                  * Operations that change tape position should write final
 372                  * tapemarks.
 373                  */
 374                 switch (op.mt_op) {
 375                         case MTFSF:
 376                         case MTBSF:
 377                         case MTFSR:
 378                         case MTBSR:
 379                         case MTREW:
 380                         case MTOFFL:
 381                         case MTEOM:
 382                         case MTRETEN:
 383                         case MTBSFM:
 384                         case MTFSFM:
 385                         case MTSEEK:
 386 #ifdef CONFIG_S390_TAPE_BLOCK
 387                                 device->blk_data.medium_changed = 1;
 388 #endif
 389                                 if (device->required_tapemarks)
 390                                         tape_std_terminate_write(device);
 391                         default:
 392                                 ;
 393                 }
 394                 rc = tape_mtop(device, op.mt_op, op.mt_count);
 395
 396                 if (op.mt_op == MTWEOF && rc == 0) {
 397                         if (op.mt_count > device->required_tapemarks)
 398                                 device->required_tapemarks = 0;
 399                         else
 400                                 device->required_tapemarks -= op.mt_count;
 401                 }
 402                 return rc;
 403         }
 404         if (no == MTIOCPOS) {
 405                 /* MTIOCPOS: query the tape position. */
 406                 struct mtpos pos;
 407
 408                 rc = tape_mtop(device, MTTELL, 1);
 409                 if (rc < 0)
 410                         return rc;
 411                 pos.mt_blkno = rc;
 412                 if (copy_to_user((char __user *) data, &pos, sizeof(pos)) != 0)
 413                         return -EFAULT;
 414                 return 0;
 415         }
 416         if (no == MTIOCGET) {
 417                 /* MTIOCGET: query the tape drive status. */
 418                 struct mtget get;
 419
 420                 memset(&get, 0, sizeof(get));
 421                 get.mt_type = MT_ISUNKNOWN;
 422                 get.mt_resid = 0 /* device->devstat.rescnt */;
 423                 get.mt_dsreg = device->tape_state;
 424                 /* FIXME: mt_gstat, mt_erreg, mt_fileno */
 425                 get.mt_gstat = 0;
 426                 get.mt_erreg = 0;
 427                 get.mt_fileno = 0;
 428                 get.mt_gstat  = device->tape_generic_status;
 429
 430                 if (device->medium_state == MS_LOADED) {
 431                         rc = tape_mtop(device, MTTELL, 1);
 432
 433                         if (rc < 0)
 434                                 return rc;
 435
 436                         if (rc == 0)
 437                                 get.mt_gstat |= GMT_BOT(~0);
 438
 439                         get.mt_blkno = rc;
 440                 }
 441
 442                 if (copy_to_user((char __user *) data, &get, sizeof(get)) != 0)
 443                         return -EFAULT;
 444
 445                 return 0;
 446         }
 447         /* Try the discipline ioctl function. */
 448         if (device->discipline->ioctl_fn == NULL)
 449                 return -EINVAL;
 450         return device->discipline->ioctl_fn(device, no, data);
 451 }
 452
 453 static long
 454 tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
 455 {
 456         struct tape_device *device = filp->private_data;
 457         int rval = -ENOIOCTLCMD;
 458
 459         if (device->discipline->ioctl_fn) {
 460                 lock_kernel();
 461                 rval = device->discipline->ioctl_fn(device, no, data);
 462                 unlock_kernel();
 463                 if (rval == -EINVAL)
 464                         rval = -ENOIOCTLCMD;
 465         }
 466
 467         return rval;
 468 }
 469
 470 /*
 471  * Initialize character device frontend.
 472  */
 473 int
 474 tapechar_init (void)
 475 {
 476         dev_t   dev;
 477
 478         if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
 479                 return -1;
 480
 481         tapechar_major = MAJOR(dev);
 482
 483         return 0;
 484 }
 485
 486 /*
 487  * cleanup
 488  */
 489 void
 490 tapechar_exit(void)
 491 {
 492         unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
 493 }