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/module.h>
  14 #include <linux/types.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/mtio.h>
  17
  18 #include <asm/uaccess.h>
  19
  20 #define TAPE_DBF_AREA   tape_core_dbf
  21
  22 #include "tape.h"
  23 #include "tape_std.h"
  24 #include "tape_class.h"
  25
  26 #define PRINTK_HEADER "TAPE_CHAR: "
  27
  28 #define TAPECHAR_MAJOR          0       /* get dynamic major */
  29
  30 /*
  31  * file operation structure for tape character frontend
  32  */
  33 static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
  34 static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
  35 static int tapechar_open(struct inode *,struct file *);
  36 static int tapechar_release(struct inode *,struct file *);
  37 static int tapechar_ioctl(struct inode *, struct file *, unsigned int,
  38                           unsigned long);
  39 static long tapechar_compat_ioctl(struct file *, unsigned int,
  40                           unsigned long);
  41
  42 static struct file_operations tape_fops =
  43 {
  44         .owner = THIS_MODULE,
  45         .read = tapechar_read,
  46         .write = tapechar_write,
  47         .ioctl = tapechar_ioctl,
  48         .compat_ioctl = tapechar_compat_ioctl,
  49         .open = tapechar_open,
  50         .release = tapechar_release,
  51 };
  52
  53 static int tapechar_major = TAPECHAR_MAJOR;
  54
  55 /*
  56  * This function is called for every new tapedevice
  57  */
  58 int
  59 tapechar_setup_device(struct tape_device * device)
  60 {
  61         char    device_name[20];
  62
  63         sprintf(device_name, "ntibm%i", device->first_minor / 2);
  64         device->nt = register_tape_dev(
  65                 &device->cdev->dev,
  66                 MKDEV(tapechar_major, device->first_minor),
  67                 &tape_fops,
  68                 device_name,
  69                 "non-rewinding"
  70         );
  71         device_name[0] = 'r';
  72         device->rt = register_tape_dev(
  73                 &device->cdev->dev,
  74                 MKDEV(tapechar_major, device->first_minor + 1),
  75                 &tape_fops,
  76                 device_name,
  77                 "rewinding"
  78         );
  79
  80         return 0;
  81 }
  82
  83 void
  84 tapechar_cleanup_device(struct tape_device *device)
  85 {
  86         unregister_tape_dev(device->rt);
  87         device->rt = NULL;
  88         unregister_tape_dev(device->nt);
  89         device->nt = NULL;
  90 }
  91
  92 /*
  93  * Terminate write command (we write two TMs and skip backward over last)
  94  * This ensures that the tape is always correctly terminated.
  95  * When the user writes afterwards a new file, he will overwrite the
  96  * second TM and therefore one TM will remain to separate the
  97  * two files on the tape...
  98  */
  99 static inline void
 100 tapechar_terminate_write(struct tape_device *device)
 101 {
 102         if (tape_mtop(device, MTWEOF, 1) == 0 &&
 103             tape_mtop(device, MTWEOF, 1) == 0)
 104                 tape_mtop(device, MTBSR, 1);
 105 }
 106
 107 static inline int
 108 tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
 109 {
 110         struct idal_buffer *new;
 111
 112         if (device->char_data.idal_buf != NULL &&
 113             device->char_data.idal_buf->size == block_size)
 114                 return 0;
 115
 116         if (block_size > MAX_BLOCKSIZE) {
 117                 DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
 118                         block_size, MAX_BLOCKSIZE);
 119                 PRINT_ERR("Invalid blocksize (%zd> %d)\n",
 120                         block_size, MAX_BLOCKSIZE);
 121                 return -EINVAL;
 122         }
 123
 124         /* The current idal buffer is not correct. Allocate a new one. */
 125         new = idal_buffer_alloc(block_size, 0);
 126         if (new == NULL)
 127                 return -ENOMEM;
 128
 129         if (device->char_data.idal_buf != NULL)
 130                 idal_buffer_free(device->char_data.idal_buf);
 131
 132         device->char_data.idal_buf = new;
 133
 134         return 0;
 135 }
 136
 137 /*
 138  * Tape device read function
 139  */
 140 ssize_t
 141 tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
 142 {
 143         struct tape_device *device;
 144         struct tape_request *request;
 145         size_t block_size;
 146         int rc;
 147
 148         DBF_EVENT(6, "TCHAR:read\n");
 149         device = (struct tape_device *) filp->private_data;
 150
 151         /*
 152          * If the tape isn't terminated yet, do it now. And since we then
 153          * are at the end of the tape there wouldn't be anything to read
 154          * anyways. So we return immediatly.
 155          */
 156         if(device->required_tapemarks) {
 157                 return tape_std_terminate_write(device);
 158         }
 159
 160         /* Find out block size to use */
 161         if (device->char_data.block_size != 0) {
 162                 if (count < device->char_data.block_size) {
 163                         DBF_EVENT(3, "TCHAR:read smaller than block "
 164                                   "size was requested\n");
 165                         return -EINVAL;
 166                 }
 167                 block_size = device->char_data.block_size;
 168         } else {
 169                 block_size = count;
 170         }
 171
 172         rc = tapechar_check_idalbuffer(device, block_size);
 173         if (rc)
 174                 return rc;
 175
 176 #ifdef CONFIG_S390_TAPE_BLOCK
 177         /* Changes position. */
 178         device->blk_data.medium_changed = 1;
 179 #endif
 180
 181         DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
 182         /* Let the discipline build the ccw chain. */
 183         request = device->discipline->read_block(device, block_size);
 184         if (IS_ERR(request))
 185                 return PTR_ERR(request);
 186         /* Execute it. */
 187         rc = tape_do_io(device, request);
 188         if (rc == 0) {
 189                 rc = block_size - request->rescnt;
 190                 DBF_EVENT(6, "TCHAR:rbytes:  %x\n", rc);
 191                 filp->f_pos += rc;
 192                 /* Copy data from idal buffer to user space. */
 193                 if (idal_buffer_to_user(device->char_data.idal_buf,
 194                                         data, rc) != 0)
 195                         rc = -EFAULT;
 196         }
 197         tape_free_request(request);
 198         return rc;
 199 }
 200
 201 /*
 202  * Tape device write function
 203  */
 204 ssize_t
 205 tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
 206 {
 207         struct tape_device *device;
 208         struct tape_request *request;
 209         size_t block_size;
 210         size_t written;
 211         int nblocks;
 212         int i, rc;
 213
 214         DBF_EVENT(6, "TCHAR:write\n");
 215         device = (struct tape_device *) filp->private_data;
 216         /* Find out block size and number of blocks */
 217         if (device->char_data.block_size != 0) {
 218                 if (count < device->char_data.block_size) {
 219                         DBF_EVENT(3, "TCHAR:write smaller than block "
 220                                   "size was requested\n");
 221                         return -EINVAL;
 222                 }
 223                 block_size = device->char_data.block_size;
 224                 nblocks = count / block_size;
 225         } else {
 226                 block_size = count;
 227                 nblocks = 1;
 228         }
 229
 230         rc = tapechar_check_idalbuffer(device, block_size);
 231         if (rc)
 232                 return rc;
 233
 234 #ifdef CONFIG_S390_TAPE_BLOCK
 235         /* Changes position. */
 236         device->blk_data.medium_changed = 1;
 237 #endif
 238
 239         DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
 240         DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
 241         /* Let the discipline build the ccw chain. */
 242         request = device->discipline->write_block(device, block_size);
 243         if (IS_ERR(request))
 244                 return PTR_ERR(request);
 245         rc = 0;
 246         written = 0;
 247         for (i = 0; i < nblocks; i++) {
 248                 /* Copy data from user space to idal buffer. */
 249                 if (idal_buffer_from_user(device->char_data.idal_buf,
 250                                           data, block_size)) {
 251                         rc = -EFAULT;
 252                         break;
 253                 }
 254                 rc = tape_do_io(device, request);
 255                 if (rc)
 256                         break;
 257                 DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
 258                           block_size - request->rescnt);
 259                 filp->f_pos += block_size - request->rescnt;
 260                 written += block_size - request->rescnt;
 261                 if (request->rescnt != 0)
 262                         break;
 263                 data += block_size;
 264         }
 265         tape_free_request(request);
 266         if (rc == -ENOSPC) {
 267                 /*
 268                  * Ok, the device has no more space. It has NOT written
 269                  * the block.
 270                  */
 271                 if (device->discipline->process_eov)
 272                         device->discipline->process_eov(device);
 273                 if (written > 0)
 274                         rc = 0;
 275
 276         }
 277
 278         /*
 279          * After doing a write we always need two tapemarks to correctly
 280          * terminate the tape (one to terminate the file, the second to
 281          * flag the end of recorded data.
 282          * Since process_eov positions the tape in front of the written
 283          * tapemark it doesn't hurt to write two marks again.
 284          */
 285         if (!rc)
 286                 device->required_tapemarks = 2;
 287
 288         return rc ? rc : written;
 289 }
 290
 291 /*
 292  * Character frontend tape device open function.
 293  */
 294 int
 295 tapechar_open (struct inode *inode, struct file *filp)
 296 {
 297         struct tape_device *device;
 298         int minor, rc;
 299
 300         DBF_EVENT(6, "TCHAR:open: %i:%i\n",
 301                 imajor(filp->f_path.dentry->d_inode),
 302                 iminor(filp->f_path.dentry->d_inode));
 303
 304         if (imajor(filp->f_path.dentry->d_inode) != tapechar_major)
 305                 return -ENODEV;
 306
 307         minor = iminor(filp->f_path.dentry->d_inode);
 308         device = tape_get_device(minor / TAPE_MINORS_PER_DEV);
 309         if (IS_ERR(device)) {
 310                 DBF_EVENT(3, "TCHAR:open: tape_get_device() failed\n");
 311                 return PTR_ERR(device);
 312         }
 313
 314
 315         rc = tape_open(device);
 316         if (rc == 0) {
 317                 filp->private_data = device;
 318                 return nonseekable_open(inode, filp);
 319         }
 320         tape_put_device(device);
 321
 322         return rc;
 323 }
 324
 325 /*
 326  * Character frontend tape device release function.
 327  */
 328
 329 int
 330 tapechar_release(struct inode *inode, struct file *filp)
 331 {
 332         struct tape_device *device;
 333
 334         DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
 335         device = (struct tape_device *) filp->private_data;
 336
 337         /*
 338          * If this is the rewinding tape minor then rewind. In that case we
 339          * write all required tapemarks. Otherwise only one to terminate the
 340          * file.
 341          */
 342         if ((iminor(inode) & 1) != 0) {
 343                 if (device->required_tapemarks)
 344                         tape_std_terminate_write(device);
 345                 tape_mtop(device, MTREW, 1);
 346         } else {
 347                 if (device->required_tapemarks > 1) {
 348                         if (tape_mtop(device, MTWEOF, 1) == 0)
 349                                 device->required_tapemarks--;
 350                 }
 351         }
 352
 353         if (device->char_data.idal_buf != NULL) {
 354                 idal_buffer_free(device->char_data.idal_buf);
 355                 device->char_data.idal_buf = NULL;
 356         }
 357         tape_release(device);
 358         filp->private_data = tape_put_device(device);
 359
 360         return 0;
 361 }
 362
 363 /*
 364  * Tape device io controls.
 365  */
 366 static int
 367 tapechar_ioctl(struct inode *inp, struct file *filp,
 368                unsigned int no, unsigned long data)
 369 {
 370         struct tape_device *device;
 371         int rc;
 372
 373         DBF_EVENT(6, "TCHAR:ioct\n");
 374
 375         device = (struct tape_device *) filp->private_data;
 376
 377         if (no == MTIOCTOP) {
 378                 struct mtop op;
 379
 380                 if (copy_from_user(&op, (char __user *) data, sizeof(op)) != 0)
 381                         return -EFAULT;
 382                 if (op.mt_count < 0)
 383                         return -EINVAL;
 384
 385                 /*
 386                  * Operations that change tape position should write final
 387                  * tapemarks.
 388                  */
 389                 switch (op.mt_op) {
 390                         case MTFSF:
 391                         case MTBSF:
 392                         case MTFSR:
 393                         case MTBSR:
 394                         case MTREW:
 395                         case MTOFFL:
 396                         case MTEOM:
 397                         case MTRETEN:
 398                         case MTBSFM:
 399                         case MTFSFM:
 400                         case MTSEEK:
 401 #ifdef CONFIG_S390_TAPE_BLOCK
 402                                 device->blk_data.medium_changed = 1;
 403 #endif
 404                                 if (device->required_tapemarks)
 405                                         tape_std_terminate_write(device);
 406                         default:
 407                                 ;
 408                 }
 409                 rc = tape_mtop(device, op.mt_op, op.mt_count);
 410
 411                 if (op.mt_op == MTWEOF && rc == 0) {
 412                         if (op.mt_count > device->required_tapemarks)
 413                                 device->required_tapemarks = 0;
 414                         else
 415                                 device->required_tapemarks -= op.mt_count;
 416                 }
 417                 return rc;
 418         }
 419         if (no == MTIOCPOS) {
 420                 /* MTIOCPOS: query the tape position. */
 421                 struct mtpos pos;
 422
 423                 rc = tape_mtop(device, MTTELL, 1);
 424                 if (rc < 0)
 425                         return rc;
 426                 pos.mt_blkno = rc;
 427                 if (copy_to_user((char __user *) data, &pos, sizeof(pos)) != 0)
 428                         return -EFAULT;
 429                 return 0;
 430         }
 431         if (no == MTIOCGET) {
 432                 /* MTIOCGET: query the tape drive status. */
 433                 struct mtget get;
 434
 435                 memset(&get, 0, sizeof(get));
 436                 get.mt_type = MT_ISUNKNOWN;
 437                 get.mt_resid = 0 /* device->devstat.rescnt */;
 438                 get.mt_dsreg = device->tape_state;
 439                 /* FIXME: mt_gstat, mt_erreg, mt_fileno */
 440                 get.mt_gstat = 0;
 441                 get.mt_erreg = 0;
 442                 get.mt_fileno = 0;
 443                 get.mt_gstat  = device->tape_generic_status;
 444
 445                 if (device->medium_state == MS_LOADED) {
 446                         rc = tape_mtop(device, MTTELL, 1);
 447
 448                         if (rc < 0)
 449                                 return rc;
 450
 451                         if (rc == 0)
 452                                 get.mt_gstat |= GMT_BOT(~0);
 453
 454                         get.mt_blkno = rc;
 455                 }
 456
 457                 if (copy_to_user((char __user *) data, &get, sizeof(get)) != 0)
 458                         return -EFAULT;
 459
 460                 return 0;
 461         }
 462         /* Try the discipline ioctl function. */
 463         if (device->discipline->ioctl_fn == NULL)
 464                 return -EINVAL;
 465         return device->discipline->ioctl_fn(device, no, data);
 466 }
 467
 468 static long
 469 tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
 470 {
 471         struct tape_device *device = filp->private_data;
 472         int rval = -ENOIOCTLCMD;
 473
 474         if (device->discipline->ioctl_fn) {
 475                 lock_kernel();
 476                 rval = device->discipline->ioctl_fn(device, no, data);
 477                 unlock_kernel();
 478                 if (rval == -EINVAL)
 479                         rval = -ENOIOCTLCMD;
 480         }
 481
 482         return rval;
 483 }
 484
 485 /*
 486  * Initialize character device frontend.
 487  */
 488 int
 489 tapechar_init (void)
 490 {
 491         dev_t   dev;
 492
 493         if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
 494                 return -1;
 495
 496         tapechar_major = MAJOR(dev);
 497         PRINT_INFO("tape gets major %d for character devices\n", MAJOR(dev));
 498
 499         return 0;
 500 }
 501
 502 /*
 503  * cleanup
 504  */
 505 void
 506 tapechar_exit(void)
 507 {
 508         PRINT_INFO("tape releases major %d for character devices\n",
 509                 tapechar_major);
 510         unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
 511 }