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_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
 150         }
 151         return ret;
 152 }
 153
 154 static struct dentry *ibmasmfs_create_file (struct super_block *sb,
 155                         struct dentry *parent,
 156                         const char *name,
 157                         const struct file_operations *fops,
 158                         void *data,
 159                         int mode)
 160 {
 161         struct dentry *dentry;
 162         struct inode *inode;
 163
 164         dentry = d_alloc_name(parent, name);
 165         if (!dentry)
 166                 return NULL;
 167
 168         inode = ibmasmfs_make_inode(sb, S_IFREG | mode);
 169         if (!inode) {
 170                 dput(dentry);
 171                 return NULL;
 172         }
 173
 174         inode->i_fop = fops;
 175         inode->i_private = data;
 176
 177         d_add(dentry, inode);
 178         return dentry;
 179 }
 180
 181 static struct dentry *ibmasmfs_create_dir (struct super_block *sb,
 182                                 struct dentry *parent,
 183                                 const char *name)
 184 {
 185         struct dentry *dentry;
 186         struct inode *inode;
 187
 188         dentry = d_alloc_name(parent, name);
 189         if (!dentry)
 190                 return NULL;
 191
 192         inode = ibmasmfs_make_inode(sb, S_IFDIR | 0500);
 193         if (!inode) {
 194                 dput(dentry);
 195                 return NULL;
 196         }
 197
 198         inode->i_op = &simple_dir_inode_operations;
 199         inode->i_fop = ibmasmfs_dir_ops;
 200
 201         d_add(dentry, inode);
 202         return dentry;
 203 }
 204
 205 int ibmasmfs_register(void)
 206 {
 207         return register_filesystem(&ibmasmfs_type);
 208 }
 209
 210 void ibmasmfs_unregister(void)
 211 {
 212         unregister_filesystem(&ibmasmfs_type);
 213 }
 214
 215 void ibmasmfs_add_sp(struct service_processor *sp)
 216 {
 217         list_add(&sp->node, &service_processors);
 218 }
 219
 220 /* struct to save state between command file operations */
 221 struct ibmasmfs_command_data {
 222         struct service_processor        *sp;
 223         struct command                  *command;
 224 };
 225
 226 /* struct to save state between event file operations */
 227 struct ibmasmfs_event_data {
 228         struct service_processor        *sp;
 229         struct event_reader             reader;
 230         int                             active;
 231 };
 232
 233 /* struct to save state between reverse heartbeat file operations */
 234 struct ibmasmfs_heartbeat_data {
 235         struct service_processor        *sp;
 236         struct reverse_heartbeat        heartbeat;
 237         int                             active;
 238 };
 239
 240 static int command_file_open(struct inode *inode, struct file *file)
 241 {
 242         struct ibmasmfs_command_data *command_data;
 243
 244         if (!inode->i_private)
 245                 return -ENODEV;
 246
 247         command_data = kmalloc(sizeof(struct ibmasmfs_command_data), GFP_KERNEL);
 248         if (!command_data)
 249                 return -ENOMEM;
 250
 251         command_data->command = NULL;
 252         command_data->sp = inode->i_private;
 253         file->private_data = command_data;
 254         return 0;
 255 }
 256
 257 static int command_file_close(struct inode *inode, struct file *file)
 258 {
 259         struct ibmasmfs_command_data *command_data = file->private_data;
 260
 261         if (command_data->command)
 262                 command_put(command_data->command);
 263
 264         kfree(command_data);
 265         return 0;
 266 }
 267
 268 static ssize_t command_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 269 {
 270         struct ibmasmfs_command_data *command_data = file->private_data;
 271         struct command *cmd;
 272         int len;
 273         unsigned long flags;
 274
 275         if (*offset < 0)
 276                 return -EINVAL;
 277         if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
 278                 return 0;
 279         if (*offset != 0)
 280                 return 0;
 281
 282         spin_lock_irqsave(&command_data->sp->lock, flags);
 283         cmd = command_data->command;
 284         if (cmd == NULL) {
 285                 spin_unlock_irqrestore(&command_data->sp->lock, flags);
 286                 return 0;
 287         }
 288         command_data->command = NULL;
 289         spin_unlock_irqrestore(&command_data->sp->lock, flags);
 290
 291         if (cmd->status != IBMASM_CMD_COMPLETE) {
 292                 command_put(cmd);
 293                 return -EIO;
 294         }
 295         len = min(count, cmd->buffer_size);
 296         if (copy_to_user(buf, cmd->buffer, len)) {
 297                 command_put(cmd);
 298                 return -EFAULT;
 299         }
 300         command_put(cmd);
 301
 302         return len;
 303 }
 304
 305 static ssize_t command_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
 306 {
 307         struct ibmasmfs_command_data *command_data = file->private_data;
 308         struct command *cmd;
 309         unsigned long flags;
 310
 311         if (*offset < 0)
 312                 return -EINVAL;
 313         if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
 314                 return 0;
 315         if (*offset != 0)
 316                 return 0;
 317
 318         /* commands are executed sequentially, only one command at a time */
 319         if (command_data->command)
 320                 return -EAGAIN;
 321
 322         cmd = ibmasm_new_command(command_data->sp, count);
 323         if (!cmd)
 324                 return -ENOMEM;
 325
 326         if (copy_from_user(cmd->buffer, ubuff, count)) {
 327                 command_put(cmd);
 328                 return -EFAULT;
 329         }
 330
 331         spin_lock_irqsave(&command_data->sp->lock, flags);
 332         if (command_data->command) {
 333                 spin_unlock_irqrestore(&command_data->sp->lock, flags);
 334                 command_put(cmd);
 335                 return -EAGAIN;
 336         }
 337         command_data->command = cmd;
 338         spin_unlock_irqrestore(&command_data->sp->lock, flags);
 339
 340         ibmasm_exec_command(command_data->sp, cmd);
 341         ibmasm_wait_for_response(cmd, get_dot_command_timeout(cmd->buffer));
 342
 343         return count;
 344 }
 345
 346 static int event_file_open(struct inode *inode, struct file *file)
 347 {
 348         struct ibmasmfs_event_data *event_data;
 349         struct service_processor *sp;
 350
 351         if (!inode->i_private)
 352                 return -ENODEV;
 353
 354         sp = inode->i_private;
 355
 356         event_data = kmalloc(sizeof(struct ibmasmfs_event_data), GFP_KERNEL);
 357         if (!event_data)
 358                 return -ENOMEM;
 359
 360         ibmasm_event_reader_register(sp, &event_data->reader);
 361
 362         event_data->sp = sp;
 363         event_data->active = 0;
 364         file->private_data = event_data;
 365         return 0;
 366 }
 367
 368 static int event_file_close(struct inode *inode, struct file *file)
 369 {
 370         struct ibmasmfs_event_data *event_data = file->private_data;
 371
 372         ibmasm_event_reader_unregister(event_data->sp, &event_data->reader);
 373         kfree(event_data);
 374         return 0;
 375 }
 376
 377 static ssize_t event_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 378 {
 379         struct ibmasmfs_event_data *event_data = file->private_data;
 380         struct event_reader *reader = &event_data->reader;
 381         struct service_processor *sp = event_data->sp;
 382         int ret;
 383         unsigned long flags;
 384
 385         if (*offset < 0)
 386                 return -EINVAL;
 387         if (count == 0 || count > IBMASM_EVENT_MAX_SIZE)
 388                 return 0;
 389         if (*offset != 0)
 390                 return 0;
 391
 392         spin_lock_irqsave(&sp->lock, flags);
 393         if (event_data->active) {
 394                 spin_unlock_irqrestore(&sp->lock, flags);
 395                 return -EBUSY;
 396         }
 397         event_data->active = 1;
 398         spin_unlock_irqrestore(&sp->lock, flags);
 399
 400         ret = ibmasm_get_next_event(sp, reader);
 401         if (ret <= 0)
 402                 goto out;
 403
 404         if (count < reader->data_size) {
 405                 ret = -EINVAL;
 406                 goto out;
 407         }
 408
 409         if (copy_to_user(buf, reader->data, reader->data_size)) {
 410                 ret = -EFAULT;
 411                 goto out;
 412         }
 413         ret = reader->data_size;
 414
 415 out:
 416         event_data->active = 0;
 417         return ret;
 418 }
 419
 420 static ssize_t event_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
 421 {
 422         struct ibmasmfs_event_data *event_data = file->private_data;
 423
 424         if (*offset < 0)
 425                 return -EINVAL;
 426         if (count != 1)
 427                 return 0;
 428         if (*offset != 0)
 429                 return 0;
 430
 431         ibmasm_cancel_next_event(&event_data->reader);
 432         return 0;
 433 }
 434
 435 static int r_heartbeat_file_open(struct inode *inode, struct file *file)
 436 {
 437         struct ibmasmfs_heartbeat_data *rhbeat;
 438
 439         if (!inode->i_private)
 440                 return -ENODEV;
 441
 442         rhbeat = kmalloc(sizeof(struct ibmasmfs_heartbeat_data), GFP_KERNEL);
 443         if (!rhbeat)
 444                 return -ENOMEM;
 445
 446         rhbeat->sp = inode->i_private;
 447         rhbeat->active = 0;
 448         ibmasm_init_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
 449         file->private_data = rhbeat;
 450         return 0;
 451 }
 452
 453 static int r_heartbeat_file_close(struct inode *inode, struct file *file)
 454 {
 455         struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 456
 457         kfree(rhbeat);
 458         return 0;
 459 }
 460
 461 static ssize_t r_heartbeat_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 462 {
 463         struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 464         unsigned long flags;
 465         int result;
 466
 467         if (*offset < 0)
 468                 return -EINVAL;
 469         if (count == 0 || count > 1024)
 470                 return 0;
 471         if (*offset != 0)
 472                 return 0;
 473
 474         /* allow only one reverse heartbeat per process */
 475         spin_lock_irqsave(&rhbeat->sp->lock, flags);
 476         if (rhbeat->active) {
 477                 spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
 478                 return -EBUSY;
 479         }
 480         rhbeat->active = 1;
 481         spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
 482
 483         result = ibmasm_start_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
 484         rhbeat->active = 0;
 485
 486         return result;
 487 }
 488
 489 static ssize_t r_heartbeat_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
 490 {
 491         struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 492
 493         if (*offset < 0)
 494                 return -EINVAL;
 495         if (count != 1)
 496                 return 0;
 497         if (*offset != 0)
 498                 return 0;
 499
 500         if (rhbeat->active)
 501                 ibmasm_stop_reverse_heartbeat(&rhbeat->heartbeat);
 502
 503         return 1;
 504 }
 505
 506 static int remote_settings_file_open(struct inode *inode, struct file *file)
 507 {
 508         file->private_data = inode->i_private;
 509         return 0;
 510 }
 511
 512 static int remote_settings_file_close(struct inode *inode, struct file *file)
 513 {
 514         return 0;
 515 }
 516
 517 static ssize_t remote_settings_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 518 {
 519         void __iomem *address = (void __iomem *)file->private_data;
 520         unsigned char *page;
 521         int retval;
 522         int len = 0;
 523         unsigned int value;
 524
 525         if (*offset < 0)
 526                 return -EINVAL;
 527         if (count == 0 || count > 1024)
 528                 return 0;
 529         if (*offset != 0)
 530                 return 0;
 531
 532         page = (unsigned char *)__get_free_page(GFP_KERNEL);
 533         if (!page)
 534                 return -ENOMEM;
 535
 536         value = readl(address);
 537         len = sprintf(page, "%d\n", value);
 538
 539         if (copy_to_user(buf, page, len)) {
 540                 retval = -EFAULT;
 541                 goto exit;
 542         }
 543         *offset += len;
 544         retval = len;
 545
 546 exit:
 547         free_page((unsigned long)page);
 548         return retval;
 549 }
 550
 551 static ssize_t remote_settings_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
 552 {
 553         void __iomem *address = (void __iomem *)file->private_data;
 554         char *buff;
 555         unsigned int value;
 556
 557         if (*offset < 0)
 558                 return -EINVAL;
 559         if (count == 0 || count > 1024)
 560                 return 0;
 561         if (*offset != 0)
 562                 return 0;
 563
 564         buff = kzalloc (count + 1, GFP_KERNEL);
 565         if (!buff)
 566                 return -ENOMEM;
 567
 568
 569         if (copy_from_user(buff, ubuff, count)) {
 570                 kfree(buff);
 571                 return -EFAULT;
 572         }
 573
 574         value = simple_strtoul(buff, NULL, 10);
 575         writel(value, address);
 576         kfree(buff);
 577
 578         return count;
 579 }
 580
 581 static const struct file_operations command_fops = {
 582         .open =         command_file_open,
 583         .release =      command_file_close,
 584         .read =         command_file_read,
 585         .write =        command_file_write,
 586 };
 587
 588 static const struct file_operations event_fops = {
 589         .open =         event_file_open,
 590         .release =      event_file_close,
 591         .read =         event_file_read,
 592         .write =        event_file_write,
 593 };
 594
 595 static const struct file_operations r_heartbeat_fops = {
 596         .open =         r_heartbeat_file_open,
 597         .release =      r_heartbeat_file_close,
 598         .read =         r_heartbeat_file_read,
 599         .write =        r_heartbeat_file_write,
 600 };
 601
 602 static const struct file_operations remote_settings_fops = {
 603         .open =         remote_settings_file_open,
 604         .release =      remote_settings_file_close,
 605         .read =         remote_settings_file_read,
 606         .write =        remote_settings_file_write,
 607 };
 608
 609
 610 static void ibmasmfs_create_files (struct super_block *sb, struct dentry *root)
 611 {
 612         struct list_head *entry;
 613         struct service_processor *sp;
 614
 615         list_for_each(entry, &service_processors) {
 616                 struct dentry *dir;
 617                 struct dentry *remote_dir;
 618                 sp = list_entry(entry, struct service_processor, node);
 619                 dir = ibmasmfs_create_dir(sb, root, sp->dirname);
 620                 if (!dir)
 621                         continue;
 622
 623                 ibmasmfs_create_file(sb, dir, "command", &command_fops, sp, S_IRUSR|S_IWUSR);
 624                 ibmasmfs_create_file(sb, dir, "event", &event_fops, sp, S_IRUSR|S_IWUSR);
 625                 ibmasmfs_create_file(sb, dir, "reverse_heartbeat", &r_heartbeat_fops, sp, S_IRUSR|S_IWUSR);
 626
 627                 remote_dir = ibmasmfs_create_dir(sb, dir, "remote_video");
 628                 if (!remote_dir)
 629                         continue;
 630
 631                 ibmasmfs_create_file(sb, remote_dir, "width", &remote_settings_fops, (void *)display_width(sp), S_IRUSR|S_IWUSR);
 632                 ibmasmfs_create_file(sb, remote_dir, "height", &remote_settings_fops, (void *)display_height(sp), S_IRUSR|S_IWUSR);
 633                 ibmasmfs_create_file(sb, remote_dir, "depth", &remote_settings_fops, (void *)display_depth(sp), S_IRUSR|S_IWUSR);
 634         }
 635 }