linux/drivers/misc/ibmasm/ibmasmfs.c
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   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 <asm/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
  87static LIST_HEAD(service_processors);
  88
  89static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode);
  90static void ibmasmfs_create_files (struct super_block *sb, struct dentry *root);
  91static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent);
  92
  93
  94static 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
 100static const struct super_operations ibmasmfs_s_ops = {
 101        .statfs         = simple_statfs,
 102        .drop_inode     = generic_delete_inode,
 103};
 104
 105static const struct file_operations *ibmasmfs_dir_ops = &simple_dir_operations;
 106
 107static 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
 114static 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
 143static 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_ino = get_next_ino();
 149                ret->i_mode = mode;
 150                ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
 151        }
 152        return ret;
 153}
 154
 155static struct dentry *ibmasmfs_create_file (struct super_block *sb,
 156                        struct dentry *parent,
 157                        const char *name,
 158                        const struct file_operations *fops,
 159                        void *data,
 160                        int mode)
 161{
 162        struct dentry *dentry;
 163        struct inode *inode;
 164
 165        dentry = d_alloc_name(parent, name);
 166        if (!dentry)
 167                return NULL;
 168
 169        inode = ibmasmfs_make_inode(sb, S_IFREG | mode);
 170        if (!inode) {
 171                dput(dentry);
 172                return NULL;
 173        }
 174
 175        inode->i_fop = fops;
 176        inode->i_private = data;
 177
 178        d_add(dentry, inode);
 179        return dentry;
 180}
 181
 182static struct dentry *ibmasmfs_create_dir (struct super_block *sb,
 183                                struct dentry *parent,
 184                                const char *name)
 185{
 186        struct dentry *dentry;
 187        struct inode *inode;
 188
 189        dentry = d_alloc_name(parent, name);
 190        if (!dentry)
 191                return NULL;
 192
 193        inode = ibmasmfs_make_inode(sb, S_IFDIR | 0500);
 194        if (!inode) {
 195                dput(dentry);
 196                return NULL;
 197        }
 198
 199        inode->i_op = &simple_dir_inode_operations;
 200        inode->i_fop = ibmasmfs_dir_ops;
 201
 202        d_add(dentry, inode);
 203        return dentry;
 204}
 205
 206int ibmasmfs_register(void)
 207{
 208        return register_filesystem(&ibmasmfs_type);
 209}
 210
 211void ibmasmfs_unregister(void)
 212{
 213        unregister_filesystem(&ibmasmfs_type);
 214}
 215
 216void ibmasmfs_add_sp(struct service_processor *sp)
 217{
 218        list_add(&sp->node, &service_processors);
 219}
 220
 221/* struct to save state between command file operations */
 222struct ibmasmfs_command_data {
 223        struct service_processor        *sp;
 224        struct command                  *command;
 225};
 226
 227/* struct to save state between event file operations */
 228struct ibmasmfs_event_data {
 229        struct service_processor        *sp;
 230        struct event_reader             reader;
 231        int                             active;
 232};
 233
 234/* struct to save state between reverse heartbeat file operations */
 235struct ibmasmfs_heartbeat_data {
 236        struct service_processor        *sp;
 237        struct reverse_heartbeat        heartbeat;
 238        int                             active;
 239};
 240
 241static int command_file_open(struct inode *inode, struct file *file)
 242{
 243        struct ibmasmfs_command_data *command_data;
 244
 245        if (!inode->i_private)
 246                return -ENODEV;
 247
 248        command_data = kmalloc(sizeof(struct ibmasmfs_command_data), GFP_KERNEL);
 249        if (!command_data)
 250                return -ENOMEM;
 251
 252        command_data->command = NULL;
 253        command_data->sp = inode->i_private;
 254        file->private_data = command_data;
 255        return 0;
 256}
 257
 258static int command_file_close(struct inode *inode, struct file *file)
 259{
 260        struct ibmasmfs_command_data *command_data = file->private_data;
 261
 262        if (command_data->command)
 263                command_put(command_data->command);
 264
 265        kfree(command_data);
 266        return 0;
 267}
 268
 269static ssize_t command_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 270{
 271        struct ibmasmfs_command_data *command_data = file->private_data;
 272        struct command *cmd;
 273        int len;
 274        unsigned long flags;
 275
 276        if (*offset < 0)
 277                return -EINVAL;
 278        if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
 279                return 0;
 280        if (*offset != 0)
 281                return 0;
 282
 283        spin_lock_irqsave(&command_data->sp->lock, flags);
 284        cmd = command_data->command;
 285        if (cmd == NULL) {
 286                spin_unlock_irqrestore(&command_data->sp->lock, flags);
 287                return 0;
 288        }
 289        command_data->command = NULL;
 290        spin_unlock_irqrestore(&command_data->sp->lock, flags);
 291
 292        if (cmd->status != IBMASM_CMD_COMPLETE) {
 293                command_put(cmd);
 294                return -EIO;
 295        }
 296        len = min(count, cmd->buffer_size);
 297        if (copy_to_user(buf, cmd->buffer, len)) {
 298                command_put(cmd);
 299                return -EFAULT;
 300        }
 301        command_put(cmd);
 302
 303        return len;
 304}
 305
 306static ssize_t command_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
 307{
 308        struct ibmasmfs_command_data *command_data = file->private_data;
 309        struct command *cmd;
 310        unsigned long flags;
 311
 312        if (*offset < 0)
 313                return -EINVAL;
 314        if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
 315                return 0;
 316        if (*offset != 0)
 317                return 0;
 318
 319        /* commands are executed sequentially, only one command at a time */
 320        if (command_data->command)
 321                return -EAGAIN;
 322
 323        cmd = ibmasm_new_command(command_data->sp, count);
 324        if (!cmd)
 325                return -ENOMEM;
 326
 327        if (copy_from_user(cmd->buffer, ubuff, count)) {
 328                command_put(cmd);
 329                return -EFAULT;
 330        }
 331
 332        spin_lock_irqsave(&command_data->sp->lock, flags);
 333        if (command_data->command) {
 334                spin_unlock_irqrestore(&command_data->sp->lock, flags);
 335                command_put(cmd);
 336                return -EAGAIN;
 337        }
 338        command_data->command = cmd;
 339        spin_unlock_irqrestore(&command_data->sp->lock, flags);
 340
 341        ibmasm_exec_command(command_data->sp, cmd);
 342        ibmasm_wait_for_response(cmd, get_dot_command_timeout(cmd->buffer));
 343
 344        return count;
 345}
 346
 347static int event_file_open(struct inode *inode, struct file *file)
 348{
 349        struct ibmasmfs_event_data *event_data;
 350        struct service_processor *sp;
 351
 352        if (!inode->i_private)
 353                return -ENODEV;
 354
 355        sp = inode->i_private;
 356
 357        event_data = kmalloc(sizeof(struct ibmasmfs_event_data), GFP_KERNEL);
 358        if (!event_data)
 359                return -ENOMEM;
 360
 361        ibmasm_event_reader_register(sp, &event_data->reader);
 362
 363        event_data->sp = sp;
 364        event_data->active = 0;
 365        file->private_data = event_data;
 366        return 0;
 367}
 368
 369static int event_file_close(struct inode *inode, struct file *file)
 370{
 371        struct ibmasmfs_event_data *event_data = file->private_data;
 372
 373        ibmasm_event_reader_unregister(event_data->sp, &event_data->reader);
 374        kfree(event_data);
 375        return 0;
 376}
 377
 378static ssize_t event_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 379{
 380        struct ibmasmfs_event_data *event_data = file->private_data;
 381        struct event_reader *reader = &event_data->reader;
 382        struct service_processor *sp = event_data->sp;
 383        int ret;
 384        unsigned long flags;
 385
 386        if (*offset < 0)
 387                return -EINVAL;
 388        if (count == 0 || count > IBMASM_EVENT_MAX_SIZE)
 389                return 0;
 390        if (*offset != 0)
 391                return 0;
 392
 393        spin_lock_irqsave(&sp->lock, flags);
 394        if (event_data->active) {
 395                spin_unlock_irqrestore(&sp->lock, flags);
 396                return -EBUSY;
 397        }
 398        event_data->active = 1;
 399        spin_unlock_irqrestore(&sp->lock, flags);
 400
 401        ret = ibmasm_get_next_event(sp, reader);
 402        if (ret <= 0)
 403                goto out;
 404
 405        if (count < reader->data_size) {
 406                ret = -EINVAL;
 407                goto out;
 408        }
 409
 410        if (copy_to_user(buf, reader->data, reader->data_size)) {
 411                ret = -EFAULT;
 412                goto out;
 413        }
 414        ret = reader->data_size;
 415
 416out:
 417        event_data->active = 0;
 418        return ret;
 419}
 420
 421static ssize_t event_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
 422{
 423        struct ibmasmfs_event_data *event_data = file->private_data;
 424
 425        if (*offset < 0)
 426                return -EINVAL;
 427        if (count != 1)
 428                return 0;
 429        if (*offset != 0)
 430                return 0;
 431
 432        ibmasm_cancel_next_event(&event_data->reader);
 433        return 0;
 434}
 435
 436static int r_heartbeat_file_open(struct inode *inode, struct file *file)
 437{
 438        struct ibmasmfs_heartbeat_data *rhbeat;
 439
 440        if (!inode->i_private)
 441                return -ENODEV;
 442
 443        rhbeat = kmalloc(sizeof(struct ibmasmfs_heartbeat_data), GFP_KERNEL);
 444        if (!rhbeat)
 445                return -ENOMEM;
 446
 447        rhbeat->sp = inode->i_private;
 448        rhbeat->active = 0;
 449        ibmasm_init_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
 450        file->private_data = rhbeat;
 451        return 0;
 452}
 453
 454static int r_heartbeat_file_close(struct inode *inode, struct file *file)
 455{
 456        struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 457
 458        kfree(rhbeat);
 459        return 0;
 460}
 461
 462static ssize_t r_heartbeat_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 463{
 464        struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 465        unsigned long flags;
 466        int result;
 467
 468        if (*offset < 0)
 469                return -EINVAL;
 470        if (count == 0 || count > 1024)
 471                return 0;
 472        if (*offset != 0)
 473                return 0;
 474
 475        /* allow only one reverse heartbeat per process */
 476        spin_lock_irqsave(&rhbeat->sp->lock, flags);
 477        if (rhbeat->active) {
 478                spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
 479                return -EBUSY;
 480        }
 481        rhbeat->active = 1;
 482        spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
 483
 484        result = ibmasm_start_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
 485        rhbeat->active = 0;
 486
 487        return result;
 488}
 489
 490static ssize_t r_heartbeat_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
 491{
 492        struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
 493
 494        if (*offset < 0)
 495                return -EINVAL;
 496        if (count != 1)
 497                return 0;
 498        if (*offset != 0)
 499                return 0;
 500
 501        if (rhbeat->active)
 502                ibmasm_stop_reverse_heartbeat(&rhbeat->heartbeat);
 503
 504        return 1;
 505}
 506
 507static int remote_settings_file_open(struct inode *inode, struct file *file)
 508{
 509        file->private_data = inode->i_private;
 510        return 0;
 511}
 512
 513static int remote_settings_file_close(struct inode *inode, struct file *file)
 514{
 515        return 0;
 516}
 517
 518static ssize_t remote_settings_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 519{
 520        void __iomem *address = (void __iomem *)file->private_data;
 521        unsigned char *page;
 522        int retval;
 523        int len = 0;
 524        unsigned int value;
 525
 526        if (*offset < 0)
 527                return -EINVAL;
 528        if (count == 0 || count > 1024)
 529                return 0;
 530        if (*offset != 0)
 531                return 0;
 532
 533        page = (unsigned char *)__get_free_page(GFP_KERNEL);
 534        if (!page)
 535                return -ENOMEM;
 536
 537        value = readl(address);
 538        len = sprintf(page, "%d\n", value);
 539
 540        if (copy_to_user(buf, page, len)) {
 541                retval = -EFAULT;
 542                goto exit;
 543        }
 544        *offset += len;
 545        retval = len;
 546
 547exit:
 548        free_page((unsigned long)page);
 549        return retval;
 550}
 551
 552static ssize_t remote_settings_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
 553{
 554        void __iomem *address = (void __iomem *)file->private_data;
 555        char *buff;
 556        unsigned int value;
 557
 558        if (*offset < 0)
 559                return -EINVAL;
 560        if (count == 0 || count > 1024)
 561                return 0;
 562        if (*offset != 0)
 563                return 0;
 564
 565        buff = kzalloc (count + 1, GFP_KERNEL);
 566        if (!buff)
 567                return -ENOMEM;
 568
 569
 570        if (copy_from_user(buff, ubuff, count)) {
 571                kfree(buff);
 572                return -EFAULT;
 573        }
 574
 575        value = simple_strtoul(buff, NULL, 10);
 576        writel(value, address);
 577        kfree(buff);
 578
 579        return count;
 580}
 581
 582static const struct file_operations command_fops = {
 583        .open =         command_file_open,
 584        .release =      command_file_close,
 585        .read =         command_file_read,
 586        .write =        command_file_write,
 587        .llseek =       generic_file_llseek,
 588};
 589
 590static 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        .llseek =       generic_file_llseek,
 596};
 597
 598static const struct file_operations r_heartbeat_fops = {
 599        .open =         r_heartbeat_file_open,
 600        .release =      r_heartbeat_file_close,
 601        .read =         r_heartbeat_file_read,
 602        .write =        r_heartbeat_file_write,
 603        .llseek =       generic_file_llseek,
 604};
 605
 606static const struct file_operations remote_settings_fops = {
 607        .open =         remote_settings_file_open,
 608        .release =      remote_settings_file_close,
 609        .read =         remote_settings_file_read,
 610        .write =        remote_settings_file_write,
 611        .llseek =       generic_file_llseek,
 612};
 613
 614
 615static void ibmasmfs_create_files (struct super_block *sb, struct dentry *root)
 616{
 617        struct list_head *entry;
 618        struct service_processor *sp;
 619
 620        list_for_each(entry, &service_processors) {
 621                struct dentry *dir;
 622                struct dentry *remote_dir;
 623                sp = list_entry(entry, struct service_processor, node);
 624                dir = ibmasmfs_create_dir(sb, root, sp->dirname);
 625                if (!dir)
 626                        continue;
 627
 628                ibmasmfs_create_file(sb, dir, "command", &command_fops, sp, S_IRUSR|S_IWUSR);
 629                ibmasmfs_create_file(sb, dir, "event", &event_fops, sp, S_IRUSR|S_IWUSR);
 630                ibmasmfs_create_file(sb, dir, "reverse_heartbeat", &r_heartbeat_fops, sp, S_IRUSR|S_IWUSR);
 631
 632                remote_dir = ibmasmfs_create_dir(sb, dir, "remote_video");
 633                if (!remote_dir)
 634                        continue;
 635
 636                ibmasmfs_create_file(sb, remote_dir, "width", &remote_settings_fops, (void *)display_width(sp), S_IRUSR|S_IWUSR);
 637                ibmasmfs_create_file(sb, remote_dir, "height", &remote_settings_fops, (void *)display_height(sp), S_IRUSR|S_IWUSR);
 638                ibmasmfs_create_file(sb, remote_dir, "depth", &remote_settings_fops, (void *)display_depth(sp), S_IRUSR|S_IWUSR);
 639        }
 640}
 641