drivers/misc/ibmasm/ibmasmfs.c

   1 /*
   2  * IBM ASM Service Processor Device Driver
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  *
  18  * Copyright (C) IBM Corporation, 2004
  19  *
  20  * Author: Max Asböck <amax@us.ibm.com>
  21  *
  22  */
  23
  24 /*
  25  * Parts of this code are based on an article by Jonathan Corbet
  26  * that appeared in Linux Weekly News.
  27  */
  28
  29
  30 /*
  31  * The IBMASM file virtual filesystem. It creates the following hierarchy
  32  * dymamically when mounted from user space:
  33  *
  34  *    /ibmasm
  35  *    |-- 0
  36  *    |   |-- command
  37  *    |   |-- event
  38  *    |   |-- reverse_heartbeat
  39  *    |   `-- remote_video
  40  *    |       |-- depth
  41  *    |       |-- height
  42  *    |       `-- width
  43  *    .
  44  *    .
  45  *    .
  46  *    `-- n
  47  *        |-- command
  48  *        |-- event
  49  *        |-- reverse_heartbeat
  50  *        `-- remote_video
  51  *            |-- depth
  52  *            |-- height
  53  *            `-- width
  54  *
  55  * For each service processor the following files are created:
  56  *
  57  * command: execute dot commands
  58  *      write: execute a dot command on the service processor
  59  *      read: return the result of a previously executed dot command
  60  *
  61  * events: listen for service processor events
  62  *      read: sleep (interruptible) until an event occurs
  63  *      write: wakeup sleeping event listener
  64  *
  65  * reverse_heartbeat: send a heartbeat to the service processor
  66  *      read: sleep (interruptible) until the reverse heartbeat fails
  67  *      write: wakeup sleeping heartbeat listener
  68  *
  69  * remote_video/width
  70  * remote_video/height
  71  * remote_video/width: control remote display settings
  72  *      write: set value
  73  *      read: read value
  74  */
  75
  76 #include <linux/fs.h>
  77 #include <linux/pagemap.h>
  78 #include <asm/uaccess.h>
  79 #include <asm/io.h>
  80 #include "ibmasm.h"
  81 #include "remote.h"
  82 #include "dot_command.h"
  83
  84 #define IBMASMFS_MAGIC 0x66726f67
  85
  86 static LIST_HEAD(service_processors);
  87
  88 static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode);
  89 static void ibmasmfs_create_files (struct super_block *sb, struct dentry *root);
  90 static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent);
  91
  92
  93 static int ibmasmfs_get_super(struct file_system_type *fst,
  94                         int flags, const char *name, void *data,
  95                         struct vfsmount *mnt)
  96 {
  97         return get_sb_single(fst, flags, data, ibmasmfs_fill_super, mnt);
  98 }
  99
 100 static struct super_operations ibmasmfs_s_ops = {
 101         .statfs         = simple_statfs,
 102         .drop_inode     = generic_delete_inode,
 103 };
 104
 105 static const struct file_operations *ibmasmfs_dir_ops = &simple_dir_operations;
 106
 107 static struct file_system_type ibmasmfs_type = {
 108         .owner          = THIS_MODULE,
 109         .name           = "ibmasmfs",
 110         .get_sb         = ibmasmfs_get_super,
 111         .kill_sb        = kill_litter_super,
 112 };
 113
 114 static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent)
 115 {
 116         struct inode *root;
 117         struct dentry *root_dentry;
 118
 119         sb->s_blocksize = PAGE_CACHE_SIZE;
 120         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 121         sb->s_magic = IBMASMFS_MAGIC;
 122         sb->s_op = &ibmasmfs_s_ops;
 123         sb->s_time_gran = 1;
 124
 125         root = ibmasmfs_make_inode (sb, S_IFDIR | 0500);
 126         if (!root)
 127                 return -ENOMEM;
 128
 129         root->i_op = &simple_dir_inode_operations;
 130         root->i_fop = ibmasmfs_dir_ops;
 131
 132         root_dentry = d_alloc_root(root);
 133         if (!root_dentry) {
 134                 iput(root);
 135                 return -ENOMEM;
 136         }
 137         sb->s_root = root_dentry;
 138
 139         ibmasmfs_create_files(sb, root_dentry);
 140         return 0;
 141 }
 142
 143 static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode)
 144 {
 145         struct inode *ret = new_inode(sb);
 146
 147         if (ret) {
 148                 ret->i_mode = mode;
 149                 ret->i_uid = ret->i_gid = 0;
 150                 ret->i_blocks = 0;
 151                 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
 152         }
 153         return ret;
 154 }
 155
 156 static struct dentry *ibmasmfs_create_file (struct super_block *sb,
 157                         struct dentry *parent,
 158                         const char *name,
 159                         const struct file_operations *fops,
 160                         void *data,
 161                         int mode)
 162 {
 163         struct dentry *dentry;
 164         struct inode *inode;
 165
 166         dentry = d_alloc_name(parent, name);
 167         if (!dentry)
 168                 return NULL;
 169
 170         inode = ibmasmfs_make_inode(sb, S_IFREG | mode);
 171         if (!inode) {
 172                 dput(dentry);
 173                 return NULL;
 174         }
 175
 176         inode->i_fop = fops;
 177         inode->i_private = data;
 178
 179         d_add(dentry, inode);
 180         return dentry;
 181 }
 182
 183 static struct dentry *ibmasmfs_create_dir (struct super_block *sb,
 184                                 struct dentry *parent,
 185                                 const char *name)
 186 {
 187         struct dentry *dentry;
 188         struct inode *inode;
 189
 190         dentry = d_alloc_name(parent, name);
 191         if (!dentry)
 192                 return NULL;
 193
 194         inode = ibmasmfs_make_inode(sb, S_IFDIR | 0500);
 195         if (!inode) {
 196                 dput(dentry);
 197                 return NULL;
 198         }
 199
 200         inode->i_op = &simple_dir_inode_operations;
 201         inode->i_fop = ibmasmfs_dir_ops;
 202
 203         d_add(dentry, inode);
 204         return dentry;
 205 }
 206
 207 int ibmasmfs_register(void)
 208 {
 209         return register_filesystem(&ibmasmfs_type);
 210 }
 211
 212 void ibmasmfs_unregister(void)
 213 {
 214         unregister_filesystem(&ibmasmfs_type);
 215 }
 216
 217 void ibmasmfs_add_sp(struct service_processor *sp)
 218 {
 219         list_add(&sp->node, &service_processors);
 220 }
 221
 222 /* struct to save state between command file operations */
 223 struct ibmasmfs_command_data {
 224         struct service_processor        *sp;
 225         struct command                  *command;
 226 };
 227
 228 /* struct to save state between event file operations */
 229 struct ibmasmfs_event_data {
 230         struct service_processor        *sp;
 231         struct event_reader             reader;
 232         int                             active;
 233 };
 234
 235 /* struct to save state between reverse heartbeat file operations */
 236 struct ibmasmfs_heartbeat_data {
 237         struct service_processor        *sp;
 238         struct reverse_heartbeat        heartbeat;
 239         int                             active;
 240 };
 241
 242 static int command_file_open(struct inode *inode, struct file *file)
 243 {
 244         struct ibmasmfs_command_data *command_data;
 245
 246         if (!inode->i_private)
 247                 return -ENODEV;
 248
 249         command_data = kmalloc(sizeof(struct ibmasmfs_command_data), GFP_KERNEL);
 250         if (!command_data)
 251                 return -ENOMEM;
 252
 253         command_data->command = NULL;
 254         command_data->sp = inode->i_private;
 255         file->private_data = command_data;
 256         return 0;
 257 }
 258
 259 static int command_file_close(struct inode *inode, struct file *file)
 260 {
 261         struct ibmasmfs_command_data *command_data = file->private_data;
 262
 263         if (command_data->command)
 264                 command_put(command_data->command);
 265
 266         kfree(command_data);
 267         return 0;
 268 }
 269
 270 static ssize_t command_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 271 {
 272         struct ibmasmfs_command_data *command_data = file->private_data;
 273         struct command *cmd;
 274         int len;
 275         unsigned long flags;
 276
 277         if (*offset < 0)
 278                 return -EINVAL;
 279         if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
 280                 return 0;
 281         if (*offset != 0)
 282                 return 0;
 283
 284         spin_lock_irqsave(&command_data->sp->lock, flags);
 285         cmd = command_data->command;
 286         if (cmd == NULL) {
 287                 spin_unlock_irqrestore(&command_data->sp->lock, flags);
 288                 return 0;
 289         }
 290         command_data->command = NULL;
 291         spin_unlock_irqrestore(&command_data->sp->lock, flags);
 292
 293         if (cmd->status != IBMASM_CMD_COMPLETE) {
 294                 command_put(cmd);
 295                 return -EIO;
 296         }
 297         len = min(count, cmd->buffer_size);
 298         if (copy_to_user(buf, cmd->buffer, len)) {
 299                 command_put(cmd);
 300                 return -EFAULT;
 301         }
 302         command_put(cmd);
 303
 304         return len;
 305 }
 306
 307 static ssize_t command_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
 308 {
 309         struct ibmasmfs_command_data *command_data = file->private_data;
 310         struct command *cmd;
 311         unsigned long flags;
 312
 313         if (*offset < 0)
 314                 return -EINVAL;
 315         if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
 316                 return 0;
 317         if (*offset != 0)
 318                 return 0;
 319
 320         /* commands are executed sequentially, only one command at a time */
 321         if (command_data->command)
 322                 return -EAGAIN;
 323
 324         cmd = ibmasm_new_command(command_data->sp, count);
 325         if (!cmd)
 326                 return -ENOMEM;
 327
 328         if (copy_from_user(cmd->buffer, ubuff, count)) {
 329                 command_put(cmd);
 330                 return -EFAULT;
 331         }
 332
 333         spin_lock_irqsave(&command_data->sp->lock, flags);
 334         if (command_data->command) {
 335                 spin_unlock_irqrestore(&command_data->sp->lock, flags);
 336                 command_put(cmd);
 337                 return -EAGAIN;
 338         }
 339         command_data->command = cmd;
 340         spin_unlock_irqrestore(&command_data->sp->lock, flags);
 341
 342         ibmasm_exec_command(command_data->sp, cmd);
 343         ibmasm_wait_for_response(cmd, get_dot_command_timeout(cmd->buffer));
 344
 345         return count;
 346 }
 347
 348 static int event_file_open(struct inode *inode, struct file *file)
 349 {
 350         struct ibmasmfs_event_data *event_data;
 351         struct service_processor *sp;
 352
 353         if (!inode->i_private)
 354                 return -ENODEV;
 355
 356         sp = inode->i_private;
 357
 358         event_data = kmalloc(sizeof(struct ibmasmfs_event_data), GFP_KERNEL);
 359         if (!event_data)
 360                 return -ENOMEM;
 361
 362         ibmasm_event_reader_register(sp, &event_data->reader);
 363
 364         event_data->sp = sp;
 365         event_data->active = 0;
 366         file->private_data = event_data;
 367         return 0;
 368 }
 369
 370 static int event_file_close(struct inode *inode, struct file *file)
 371 {
 372         struct ibmasmfs_event_data *event_data = file->private_data;
 373
 374         ibmasm_event_reader_unregister(event_data->sp, &event_data->reader);
 375         kfree(event_data);
 376         return 0;
 377 }
 378
 379 static ssize_t event_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 380 {
 381         struct ibmasmfs_event_data *event_data = file->private_data;
 382         struct event_reader *reader = &event_data->reader;
 383         struct service_processor *sp = event_data->sp;
 384         int ret;
 385         unsigned long flags;
 386
 387         if (*offset < 0)
 388                 return -EINVAL;
 389         if (count == 0 || count > IBMASM_EVENT_MAX_SIZE)
 390                 return 0;
 391         if (*offset != 0)
 392                 return 0;
 393
 394         spin_lock_irqsave(&sp->lock, flags);
 395         if (event_data->active) {
 396                 spin_unlock_irqrestore(&sp->lock, flags);
 397                 return -EBUSY;
 398         }
 399         event_data->active = 1;
 400         spin_unlock_irqrestore(&sp->lock, flags);
 401
 402         ret = ibmasm_get_next_event(sp, reader);
 403         if (ret <= 0)
 404                 goto out;
 405
 406         if (count < reader->data_size) {
 407                 ret = -EINVAL;
 408                 goto out;
 409         }
 410
 411         if (copy_to_user(buf, reader->data, reader->data_size)) {
 412                 ret = -EFAULT;
 413                 goto out;
 414         }
 415         ret = reader->data_size;
 416
 417 out:
 418         event_data->active = 0;
 419         return ret;
 420 }
 421
 422 static ssize_t event_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
 423 {
 424         struct ibmasmfs_event_data *event_data = file->private_data;
 425
 426         if (*offset < 0)
 427                 return -EINVAL;
 428         if (count != 1)
 429                 return 0;
 430         if (*offset != 0)
 431                 return 0;
 432
 433         ibmasm_cancel_next_event(&event_data->reader);
 434         return 0;
 435 }
 436
 437 static int r_heartbeat_file_open(struct inode *inode, struct file *file)
 438 {
 439         struct ibmasmfs_heartbeat_data *rhbeat;
 440
 441         if (!inode->i_private)
 442                 return -ENODEV;
 443
 444         rhbeat = kmalloc(sizeof(struct ibmasmfs_heartbeat_data), GFP_KERNEL);
 445         if (!rhbeat)
 446                 return -ENOMEM;
 447
 448         rhbeat->sp = inode->i_private;
 449         rhbeat->active = 0;
 450         ibmasm_init_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
 451         file->private_data = rhbeat;
 452         return 0;
 453 }
 454
 455 static int r_heartbeat_file_close(struct inode *inode, struct file *file)
 456 {
 457         struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 458
 459         kfree(rhbeat);
 460         return 0;
 461 }
 462
 463 static ssize_t r_heartbeat_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 464 {
 465         struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 466         unsigned long flags;
 467         int result;
 468
 469         if (*offset < 0)
 470                 return -EINVAL;
 471         if (count == 0 || count > 1024)
 472                 return 0;
 473         if (*offset != 0)
 474                 return 0;
 475
 476         /* allow only one reverse heartbeat per process */
 477         spin_lock_irqsave(&rhbeat->sp->lock, flags);
 478         if (rhbeat->active) {
 479                 spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
 480                 return -EBUSY;
 481         }
 482         rhbeat->active = 1;
 483         spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
 484
 485         result = ibmasm_start_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
 486         rhbeat->active = 0;
 487
 488         return result;
 489 }
 490
 491 static ssize_t r_heartbeat_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
 492 {
 493         struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 494
 495         if (*offset < 0)
 496                 return -EINVAL;
 497         if (count != 1)
 498                 return 0;
 499         if (*offset != 0)
 500                 return 0;
 501
 502         if (rhbeat->active)
 503                 ibmasm_stop_reverse_heartbeat(&rhbeat->heartbeat);
 504
 505         return 1;
 506 }
 507
 508 static int remote_settings_file_open(struct inode *inode, struct file *file)
 509 {
 510         file->private_data = inode->i_private;
 511         return 0;
 512 }
 513
 514 static int remote_settings_file_close(struct inode *inode, struct file *file)
 515 {
 516         return 0;
 517 }
 518
 519 static ssize_t remote_settings_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 520 {
 521         void __iomem *address = (void __iomem *)file->private_data;
 522         unsigned char *page;
 523         int retval;
 524         int len = 0;
 525         unsigned int value;
 526
 527         if (*offset < 0)
 528                 return -EINVAL;
 529         if (count == 0 || count > 1024)
 530                 return 0;
 531         if (*offset != 0)
 532                 return 0;
 533
 534         page = (unsigned char *)__get_free_page(GFP_KERNEL);
 535         if (!page)
 536                 return -ENOMEM;
 537
 538         value = readl(address);
 539         len = sprintf(page, "%d\n", value);
 540
 541         if (copy_to_user(buf, page, len)) {
 542                 retval = -EFAULT;
 543                 goto exit;
 544         }
 545         *offset += len;
 546         retval = len;
 547
 548 exit:
 549         free_page((unsigned long)page);
 550         return retval;
 551 }
 552
 553 static ssize_t remote_settings_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
 554 {
 555         void __iomem *address = (void __iomem *)file->private_data;
 556         char *buff;
 557         unsigned int value;
 558
 559         if (*offset < 0)
 560                 return -EINVAL;
 561         if (count == 0 || count > 1024)
 562                 return 0;
 563         if (*offset != 0)
 564                 return 0;
 565
 566         buff = kzalloc (count + 1, GFP_KERNEL);
 567         if (!buff)
 568                 return -ENOMEM;
 569
 570
 571         if (copy_from_user(buff, ubuff, count)) {
 572                 kfree(buff);
 573                 return -EFAULT;
 574         }
 575
 576         value = simple_strtoul(buff, NULL, 10);
 577         writel(value, address);
 578         kfree(buff);
 579
 580         return count;
 581 }
 582
 583 static const struct file_operations command_fops = {
 584         .open =         command_file_open,
 585         .release =      command_file_close,
 586         .read =         command_file_read,
 587         .write =        command_file_write,
 588 };
 589
 590 static const struct file_operations event_fops = {
 591         .open =         event_file_open,
 592         .release =      event_file_close,
 593         .read =         event_file_read,
 594         .write =        event_file_write,
 595 };
 596
 597 static const struct file_operations r_heartbeat_fops = {
 598         .open =         r_heartbeat_file_open,
 599         .release =      r_heartbeat_file_close,
 600         .read =         r_heartbeat_file_read,
 601         .write =        r_heartbeat_file_write,
 602 };
 603
 604 static const struct file_operations remote_settings_fops = {
 605         .open =         remote_settings_file_open,
 606         .release =      remote_settings_file_close,
 607         .read =         remote_settings_file_read,
 608         .write =        remote_settings_file_write,
 609 };
 610
 611
 612 static void ibmasmfs_create_files (struct super_block *sb, struct dentry *root)
 613 {
 614         struct list_head *entry;
 615         struct service_processor *sp;
 616
 617         list_for_each(entry, &service_processors) {
 618                 struct dentry *dir;
 619                 struct dentry *remote_dir;
 620                 sp = list_entry(entry, struct service_processor, node);
 621                 dir = ibmasmfs_create_dir(sb, root, sp->dirname);
 622                 if (!dir)
 623                         continue;
 624
 625                 ibmasmfs_create_file(sb, dir, "command", &command_fops, sp, S_IRUSR|S_IWUSR);
 626                 ibmasmfs_create_file(sb, dir, "event", &event_fops, sp, S_IRUSR|S_IWUSR);
 627                 ibmasmfs_create_file(sb, dir, "reverse_heartbeat", &r_heartbeat_fops, sp, S_IRUSR|S_IWUSR);
 628
 629                 remote_dir = ibmasmfs_create_dir(sb, dir, "remote_video");
 630                 if (!remote_dir)
 631                         continue;
 632
 633                 ibmasmfs_create_file(sb, remote_dir, "width", &remote_settings_fops, (void *)display_width(sp), S_IRUSR|S_IWUSR);
 634                 ibmasmfs_create_file(sb, remote_dir, "height", &remote_settings_fops, (void *)display_height(sp), S_IRUSR|S_IWUSR);
 635                 ibmasmfs_create_file(sb, remote_dir, "depth", &remote_settings_fops, (void *)display_depth(sp), S_IRUSR|S_IWUSR);
 636         }
 637 }