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  * dynamically 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 <linux/slab.h>
  79 #include <linux/uaccess.h>
  80 #include <asm/io.h>
  81 #include "ibmasm.h"
  82 #include "remote.h"
  83 #include "dot_command.h"
  84
  85 #define IBMASMFS_MAGIC 0x66726f67
  86
  87 static LIST_HEAD(service_processors);
  88
  89 static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode);
  90 static void ibmasmfs_create_files (struct super_block *sb);
  91 static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent);
  92
  93
  94 static struct dentry *ibmasmfs_mount(struct file_system_type *fst,
  95                         int flags, const char *name, void *data)
  96 {
  97         return mount_single(fst, flags, data, ibmasmfs_fill_super);
  98 }
  99
 100 static const 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         .mount          = ibmasmfs_mount,
 111         .kill_sb        = kill_litter_super,
 112 };
 113 MODULE_ALIAS_FS("ibmasmfs");
 114
 115 static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent)
 116 {
 117         struct inode *root;
 118
 119         sb->s_blocksize = PAGE_SIZE;
 120         sb->s_blocksize_bits = PAGE_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         sb->s_root = d_make_root(root);
 133         if (!sb->s_root)
 134                 return -ENOMEM;
 135
 136         ibmasmfs_create_files(sb);
 137         return 0;
 138 }
 139
 140 static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode)
 141 {
 142         struct inode *ret = new_inode(sb);
 143
 144         if (ret) {
 145                 ret->i_ino = get_next_ino();
 146                 ret->i_mode = mode;
 147                 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret);
 148         }
 149         return ret;
 150 }
 151
 152 static struct dentry *ibmasmfs_create_file(struct dentry *parent,
 153                         const char *name,
 154                         const struct file_operations *fops,
 155                         void *data,
 156                         int mode)
 157 {
 158         struct dentry *dentry;
 159         struct inode *inode;
 160
 161         dentry = d_alloc_name(parent, name);
 162         if (!dentry)
 163                 return NULL;
 164
 165         inode = ibmasmfs_make_inode(parent->d_sb, S_IFREG | mode);
 166         if (!inode) {
 167                 dput(dentry);
 168                 return NULL;
 169         }
 170
 171         inode->i_fop = fops;
 172         inode->i_private = data;
 173
 174         d_add(dentry, inode);
 175         return dentry;
 176 }
 177
 178 static struct dentry *ibmasmfs_create_dir(struct dentry *parent,
 179                                 const char *name)
 180 {
 181         struct dentry *dentry;
 182         struct inode *inode;
 183
 184         dentry = d_alloc_name(parent, name);
 185         if (!dentry)
 186                 return NULL;
 187
 188         inode = ibmasmfs_make_inode(parent->d_sb, S_IFDIR | 0500);
 189         if (!inode) {
 190                 dput(dentry);
 191                 return NULL;
 192         }
 193
 194         inode->i_op = &simple_dir_inode_operations;
 195         inode->i_fop = ibmasmfs_dir_ops;
 196
 197         d_add(dentry, inode);
 198         return dentry;
 199 }
 200
 201 int ibmasmfs_register(void)
 202 {
 203         return register_filesystem(&ibmasmfs_type);
 204 }
 205
 206 void ibmasmfs_unregister(void)
 207 {
 208         unregister_filesystem(&ibmasmfs_type);
 209 }
 210
 211 void ibmasmfs_add_sp(struct service_processor *sp)
 212 {
 213         list_add(&sp->node, &service_processors);
 214 }
 215
 216 /* struct to save state between command file operations */
 217 struct ibmasmfs_command_data {
 218         struct service_processor        *sp;
 219         struct command                  *command;
 220 };
 221
 222 /* struct to save state between event file operations */
 223 struct ibmasmfs_event_data {
 224         struct service_processor        *sp;
 225         struct event_reader             reader;
 226         int                             active;
 227 };
 228
 229 /* struct to save state between reverse heartbeat file operations */
 230 struct ibmasmfs_heartbeat_data {
 231         struct service_processor        *sp;
 232         struct reverse_heartbeat        heartbeat;
 233         int                             active;
 234 };
 235
 236 static int command_file_open(struct inode *inode, struct file *file)
 237 {
 238         struct ibmasmfs_command_data *command_data;
 239
 240         if (!inode->i_private)
 241                 return -ENODEV;
 242
 243         command_data = kmalloc(sizeof(struct ibmasmfs_command_data), GFP_KERNEL);
 244         if (!command_data)
 245                 return -ENOMEM;
 246
 247         command_data->command = NULL;
 248         command_data->sp = inode->i_private;
 249         file->private_data = command_data;
 250         return 0;
 251 }
 252
 253 static int command_file_close(struct inode *inode, struct file *file)
 254 {
 255         struct ibmasmfs_command_data *command_data = file->private_data;
 256
 257         if (command_data->command)
 258                 command_put(command_data->command);
 259
 260         kfree(command_data);
 261         return 0;
 262 }
 263
 264 static ssize_t command_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 265 {
 266         struct ibmasmfs_command_data *command_data = file->private_data;
 267         struct command *cmd;
 268         int len;
 269         unsigned long flags;
 270
 271         if (*offset < 0)
 272                 return -EINVAL;
 273         if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
 274                 return 0;
 275         if (*offset != 0)
 276                 return 0;
 277
 278         spin_lock_irqsave(&command_data->sp->lock, flags);
 279         cmd = command_data->command;
 280         if (cmd == NULL) {
 281                 spin_unlock_irqrestore(&command_data->sp->lock, flags);
 282                 return 0;
 283         }
 284         command_data->command = NULL;
 285         spin_unlock_irqrestore(&command_data->sp->lock, flags);
 286
 287         if (cmd->status != IBMASM_CMD_COMPLETE) {
 288                 command_put(cmd);
 289                 return -EIO;
 290         }
 291         len = min(count, cmd->buffer_size);
 292         if (copy_to_user(buf, cmd->buffer, len)) {
 293                 command_put(cmd);
 294                 return -EFAULT;
 295         }
 296         command_put(cmd);
 297
 298         return len;
 299 }
 300
 301 static ssize_t command_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
 302 {
 303         struct ibmasmfs_command_data *command_data = file->private_data;
 304         struct command *cmd;
 305         unsigned long flags;
 306
 307         if (*offset < 0)
 308                 return -EINVAL;
 309         if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
 310                 return 0;
 311         if (*offset != 0)
 312                 return 0;
 313
 314         /* commands are executed sequentially, only one command at a time */
 315         if (command_data->command)
 316                 return -EAGAIN;
 317
 318         cmd = ibmasm_new_command(command_data->sp, count);
 319         if (!cmd)
 320                 return -ENOMEM;
 321
 322         if (copy_from_user(cmd->buffer, ubuff, count)) {
 323                 command_put(cmd);
 324                 return -EFAULT;
 325         }
 326
 327         spin_lock_irqsave(&command_data->sp->lock, flags);
 328         if (command_data->command) {
 329                 spin_unlock_irqrestore(&command_data->sp->lock, flags);
 330                 command_put(cmd);
 331                 return -EAGAIN;
 332         }
 333         command_data->command = cmd;
 334         spin_unlock_irqrestore(&command_data->sp->lock, flags);
 335
 336         ibmasm_exec_command(command_data->sp, cmd);
 337         ibmasm_wait_for_response(cmd, get_dot_command_timeout(cmd->buffer));
 338
 339         return count;
 340 }
 341
 342 static int event_file_open(struct inode *inode, struct file *file)
 343 {
 344         struct ibmasmfs_event_data *event_data;
 345         struct service_processor *sp;
 346
 347         if (!inode->i_private)
 348                 return -ENODEV;
 349
 350         sp = inode->i_private;
 351
 352         event_data = kmalloc(sizeof(struct ibmasmfs_event_data), GFP_KERNEL);
 353         if (!event_data)
 354                 return -ENOMEM;
 355
 356         ibmasm_event_reader_register(sp, &event_data->reader);
 357
 358         event_data->sp = sp;
 359         event_data->active = 0;
 360         file->private_data = event_data;
 361         return 0;
 362 }
 363
 364 static int event_file_close(struct inode *inode, struct file *file)
 365 {
 366         struct ibmasmfs_event_data *event_data = file->private_data;
 367
 368         ibmasm_event_reader_unregister(event_data->sp, &event_data->reader);
 369         kfree(event_data);
 370         return 0;
 371 }
 372
 373 static ssize_t event_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 374 {
 375         struct ibmasmfs_event_data *event_data = file->private_data;
 376         struct event_reader *reader = &event_data->reader;
 377         struct service_processor *sp = event_data->sp;
 378         int ret;
 379         unsigned long flags;
 380
 381         if (*offset < 0)
 382                 return -EINVAL;
 383         if (count == 0 || count > IBMASM_EVENT_MAX_SIZE)
 384                 return 0;
 385         if (*offset != 0)
 386                 return 0;
 387
 388         spin_lock_irqsave(&sp->lock, flags);
 389         if (event_data->active) {
 390                 spin_unlock_irqrestore(&sp->lock, flags);
 391                 return -EBUSY;
 392         }
 393         event_data->active = 1;
 394         spin_unlock_irqrestore(&sp->lock, flags);
 395
 396         ret = ibmasm_get_next_event(sp, reader);
 397         if (ret <= 0)
 398                 goto out;
 399
 400         if (count < reader->data_size) {
 401                 ret = -EINVAL;
 402                 goto out;
 403         }
 404
 405         if (copy_to_user(buf, reader->data, reader->data_size)) {
 406                 ret = -EFAULT;
 407                 goto out;
 408         }
 409         ret = reader->data_size;
 410
 411 out:
 412         event_data->active = 0;
 413         return ret;
 414 }
 415
 416 static ssize_t event_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
 417 {
 418         struct ibmasmfs_event_data *event_data = file->private_data;
 419
 420         if (*offset < 0)
 421                 return -EINVAL;
 422         if (count != 1)
 423                 return 0;
 424         if (*offset != 0)
 425                 return 0;
 426
 427         ibmasm_cancel_next_event(&event_data->reader);
 428         return 0;
 429 }
 430
 431 static int r_heartbeat_file_open(struct inode *inode, struct file *file)
 432 {
 433         struct ibmasmfs_heartbeat_data *rhbeat;
 434
 435         if (!inode->i_private)
 436                 return -ENODEV;
 437
 438         rhbeat = kmalloc(sizeof(struct ibmasmfs_heartbeat_data), GFP_KERNEL);
 439         if (!rhbeat)
 440                 return -ENOMEM;
 441
 442         rhbeat->sp = inode->i_private;
 443         rhbeat->active = 0;
 444         ibmasm_init_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
 445         file->private_data = rhbeat;
 446         return 0;
 447 }
 448
 449 static int r_heartbeat_file_close(struct inode *inode, struct file *file)
 450 {
 451         struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 452
 453         kfree(rhbeat);
 454         return 0;
 455 }
 456
 457 static ssize_t r_heartbeat_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 458 {
 459         struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 460         unsigned long flags;
 461         int result;
 462
 463         if (*offset < 0)
 464                 return -EINVAL;
 465         if (count == 0 || count > 1024)
 466                 return 0;
 467         if (*offset != 0)
 468                 return 0;
 469
 470         /* allow only one reverse heartbeat per process */
 471         spin_lock_irqsave(&rhbeat->sp->lock, flags);
 472         if (rhbeat->active) {
 473                 spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
 474                 return -EBUSY;
 475         }
 476         rhbeat->active = 1;
 477         spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
 478
 479         result = ibmasm_start_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
 480         rhbeat->active = 0;
 481
 482         return result;
 483 }
 484
 485 static ssize_t r_heartbeat_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
 486 {
 487         struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 488
 489         if (*offset < 0)
 490                 return -EINVAL;
 491         if (count != 1)
 492                 return 0;
 493         if (*offset != 0)
 494                 return 0;
 495
 496         if (rhbeat->active)
 497                 ibmasm_stop_reverse_heartbeat(&rhbeat->heartbeat);
 498
 499         return 1;
 500 }
 501
 502 static int remote_settings_file_close(struct inode *inode, struct file *file)
 503 {
 504         return 0;
 505 }
 506
 507 static ssize_t remote_settings_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 508 {
 509         void __iomem *address = (void __iomem *)file->private_data;
 510         unsigned char *page;
 511         int retval;
 512         int len = 0;
 513         unsigned int value;
 514
 515         if (*offset < 0)
 516                 return -EINVAL;
 517         if (count == 0 || count > 1024)
 518                 return 0;
 519         if (*offset != 0)
 520                 return 0;
 521
 522         page = (unsigned char *)__get_free_page(GFP_KERNEL);
 523         if (!page)
 524                 return -ENOMEM;
 525
 526         value = readl(address);
 527         len = sprintf(page, "%d\n", value);
 528
 529         if (copy_to_user(buf, page, len)) {
 530                 retval = -EFAULT;
 531                 goto exit;
 532         }
 533         *offset += len;
 534         retval = len;
 535
 536 exit:
 537         free_page((unsigned long)page);
 538         return retval;
 539 }
 540
 541 static ssize_t remote_settings_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
 542 {
 543         void __iomem *address = (void __iomem *)file->private_data;
 544         char *buff;
 545         unsigned int value;
 546
 547         if (*offset < 0)
 548                 return -EINVAL;
 549         if (count == 0 || count > 1024)
 550                 return 0;
 551         if (*offset != 0)
 552                 return 0;
 553
 554         buff = kzalloc (count + 1, GFP_KERNEL);
 555         if (!buff)
 556                 return -ENOMEM;
 557
 558
 559         if (copy_from_user(buff, ubuff, count)) {
 560                 kfree(buff);
 561                 return -EFAULT;
 562         }
 563
 564         value = simple_strtoul(buff, NULL, 10);
 565         writel(value, address);
 566         kfree(buff);
 567
 568         return count;
 569 }
 570
 571 static const struct file_operations command_fops = {
 572         .open =         command_file_open,
 573         .release =      command_file_close,
 574         .read =         command_file_read,
 575         .write =        command_file_write,
 576         .llseek =       generic_file_llseek,
 577 };
 578
 579 static const struct file_operations event_fops = {
 580         .open =         event_file_open,
 581         .release =      event_file_close,
 582         .read =         event_file_read,
 583         .write =        event_file_write,
 584         .llseek =       generic_file_llseek,
 585 };
 586
 587 static const struct file_operations r_heartbeat_fops = {
 588         .open =         r_heartbeat_file_open,
 589         .release =      r_heartbeat_file_close,
 590         .read =         r_heartbeat_file_read,
 591         .write =        r_heartbeat_file_write,
 592         .llseek =       generic_file_llseek,
 593 };
 594
 595 static const struct file_operations remote_settings_fops = {
 596         .open =         simple_open,
 597         .release =      remote_settings_file_close,
 598         .read =         remote_settings_file_read,
 599         .write =        remote_settings_file_write,
 600         .llseek =       generic_file_llseek,
 601 };
 602
 603
 604 static void ibmasmfs_create_files (struct super_block *sb)
 605 {
 606         struct list_head *entry;
 607         struct service_processor *sp;
 608
 609         list_for_each(entry, &service_processors) {
 610                 struct dentry *dir;
 611                 struct dentry *remote_dir;
 612                 sp = list_entry(entry, struct service_processor, node);
 613                 dir = ibmasmfs_create_dir(sb->s_root, sp->dirname);
 614                 if (!dir)
 615                         continue;
 616
 617                 ibmasmfs_create_file(dir, "command", &command_fops, sp, S_IRUSR|S_IWUSR);
 618                 ibmasmfs_create_file(dir, "event", &event_fops, sp, S_IRUSR|S_IWUSR);
 619                 ibmasmfs_create_file(dir, "reverse_heartbeat", &r_heartbeat_fops, sp, S_IRUSR|S_IWUSR);
 620
 621                 remote_dir = ibmasmfs_create_dir(dir, "remote_video");
 622                 if (!remote_dir)
 623                         continue;
 624
 625                 ibmasmfs_create_file(remote_dir, "width", &remote_settings_fops, (void *)display_width(sp), S_IRUSR|S_IWUSR);
 626                 ibmasmfs_create_file(remote_dir, "height", &remote_settings_fops, (void *)display_height(sp), S_IRUSR|S_IWUSR);
 627                 ibmasmfs_create_file(remote_dir, "depth", &remote_settings_fops, (void *)display_depth(sp), S_IRUSR|S_IWUSR);
 628         }
 629 }