aboutsummaryrefslogtreecommitdiff
path: root/drivers/misc/ibmasm/ibmasmfs.c
blob: 6673e578b3e9a00bce4a949cc19495359c66ebda (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
/*
 * IBM ASM Service Processor Device Driver
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) IBM Corporation, 2004
 *
 * Author: Max Asböck <amax@us.ibm.com>
 *
 */

/*
 * Parts of this code are based on an article by Jonathan Corbet
 * that appeared in Linux Weekly News.
 */


/*
 * The IBMASM file virtual filesystem. It creates the following hierarchy
 * dynamically when mounted from user space:
 *
 *    /ibmasm
 *    |-- 0
 *    |   |-- command
 *    |   |-- event
 *    |   |-- reverse_heartbeat
 *    |   `-- remote_video
 *    |       |-- depth
 *    |       |-- height
 *    |       `-- width
 *    .
 *    .
 *    .
 *    `-- n
 *        |-- command
 *        |-- event
 *        |-- reverse_heartbeat
 *        `-- remote_video
 *            |-- depth
 *            |-- height
 *            `-- width
 *
 * For each service processor the following files are created:
 *
 * command: execute dot commands
 *	write: execute a dot command on the service processor
 *	read: return the result of a previously executed dot command
 *
 * events: listen for service processor events
 *	read: sleep (interruptible) until an event occurs
 *      write: wakeup sleeping event listener
 *
 * reverse_heartbeat: send a heartbeat to the service processor
 *	read: sleep (interruptible) until the reverse heartbeat fails
 *      write: wakeup sleeping heartbeat listener
 *
 * remote_video/width
 * remote_video/height
 * remote_video/width: control remote display settings
 *	write: set value
 *	read: read value
 */

#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include "ibmasm.h"
#include "remote.h"
#include "dot_command.h"

#define IBMASMFS_MAGIC 0x66726f67

static LIST_HEAD(service_processors);

static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode);
static void ibmasmfs_create_files (struct super_block *sb);
static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent);


static struct dentry *ibmasmfs_mount(struct file_system_type *fst,
			int flags, const char *name, void *data)
{
	return mount_single(fst, flags, data, ibmasmfs_fill_super);
}

static const struct super_operations ibmasmfs_s_ops = {
	.statfs		= simple_statfs,
	.drop_inode	= generic_delete_inode,
};

static const struct file_operations *ibmasmfs_dir_ops = &simple_dir_operations;

static struct file_system_type ibmasmfs_type = {
	.owner          = THIS_MODULE,
	.name           = "ibmasmfs",
	.mount          = ibmasmfs_mount,
	.kill_sb        = kill_litter_super,
};

static int ibmasmfs_fill_super (struct super_block *sb, void *data, int silent)
{
	struct inode *root;

	sb->s_blocksize = PAGE_CACHE_SIZE;
	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	sb->s_magic = IBMASMFS_MAGIC;
	sb->s_op = &ibmasmfs_s_ops;
	sb->s_time_gran = 1;

	root = ibmasmfs_make_inode (sb, S_IFDIR | 0500);
	if (!root)
		return -ENOMEM;

	root->i_op = &simple_dir_inode_operations;
	root->i_fop = ibmasmfs_dir_ops;

	sb->s_root = d_make_root(root);
	if (!sb->s_root)
		return -ENOMEM;

	ibmasmfs_create_files(sb);
	return 0;
}

static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode)
{
	struct inode *ret = new_inode(sb);

	if (ret) {
		ret->i_ino = get_next_ino();
		ret->i_mode = mode;
		ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
	}
	return ret;
}

static struct dentry *ibmasmfs_create_file (struct super_block *sb,
			struct dentry *parent,
			const char *name,
			const struct file_operations *fops,
			void *data,
			int mode)
{
	struct dentry *dentry;
	struct inode *inode;

	dentry = d_alloc_name(parent, name);
	if (!dentry)
		return NULL;

	inode = ibmasmfs_make_inode(sb, S_IFREG | mode);
	if (!inode) {
		dput(dentry);
		return NULL;
	}

	inode->i_fop = fops;
	inode->i_private = data;

	d_add(dentry, inode);
	return dentry;
}

static struct dentry *ibmasmfs_create_dir (struct super_block *sb,
				struct dentry *parent,
				const char *name)
{
	struct dentry *dentry;
	struct inode *inode;

	dentry = d_alloc_name(parent, name);
	if (!dentry)
		return NULL;

	inode = ibmasmfs_make_inode(sb, S_IFDIR | 0500);
	if (!inode) {
		dput(dentry);
		return NULL;
	}

	inode->i_op = &simple_dir_inode_operations;
	inode->i_fop = ibmasmfs_dir_ops;

	d_add(dentry, inode);
	return dentry;
}

int ibmasmfs_register(void)
{
	return register_filesystem(&ibmasmfs_type);
}

void ibmasmfs_unregister(void)
{
	unregister_filesystem(&ibmasmfs_type);
}

void ibmasmfs_add_sp(struct service_processor *sp)
{
	list_add(&sp->node, &service_processors);
}

/* struct to save state between command file operations */
struct ibmasmfs_command_data {
	struct service_processor	*sp;
	struct command			*command;
};

/* struct to save state between event file operations */
struct ibmasmfs_event_data {
	struct service_processor	*sp;
	struct event_reader		reader;
	int				active;
};

/* struct to save state between reverse heartbeat file operations */
struct ibmasmfs_heartbeat_data {
	struct service_processor	*sp;
	struct reverse_heartbeat	heartbeat;
	int				active;
};

static int command_file_open(struct inode *inode, struct file *file)
{
	struct ibmasmfs_command_data *command_data;

	if (!inode->i_private)
		return -ENODEV;

	command_data = kmalloc(sizeof(struct ibmasmfs_command_data), GFP_KERNEL);
	if (!command_data)
		return -ENOMEM;

	command_data->command = NULL;
	command_data->sp = inode->i_private;
	file->private_data = command_data;
	return 0;
}

static int command_file_close(struct inode *inode, struct file *file)
{
	struct ibmasmfs_command_data *command_data = file->private_data;

	if (command_data->command)
		command_put(command_data->command);

	kfree(command_data);
	return 0;
}

static ssize_t command_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
	struct ibmasmfs_command_data *command_data = file->private_data;
	struct command *cmd;
	int len;
	unsigned long flags;

	if (*offset < 0)
		return -EINVAL;
	if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
		return 0;
	if (*offset != 0)
		return 0;

	spin_lock_irqsave(&command_data->sp->lock, flags);
	cmd = command_data->command;
	if (cmd == NULL) {
		spin_unlock_irqrestore(&command_data->sp->lock, flags);
		return 0;
	}
	command_data->command = NULL;
	spin_unlock_irqrestore(&command_data->sp->lock, flags);

	if (cmd->status != IBMASM_CMD_COMPLETE) {
		command_put(cmd);
		return -EIO;
	}
	len = min(count, cmd->buffer_size);
	if (copy_to_user(buf, cmd->buffer, len)) {
		command_put(cmd);
		return -EFAULT;
	}
	command_put(cmd);

	return len;
}

static ssize_t command_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
{
	struct ibmasmfs_command_data *command_data = file->private_data;
	struct command *cmd;
	unsigned long flags;

	if (*offset < 0)
		return -EINVAL;
	if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
		return 0;
	if (*offset != 0)
		return 0;

	/* commands are executed sequentially, only one command at a time */
	if (command_data->command)
		return -EAGAIN;

	cmd = ibmasm_new_command(command_data->sp, count);
	if (!cmd)
		return -ENOMEM;

	if (copy_from_user(cmd->buffer, ubuff, count)) {
		command_put(cmd);
		return -EFAULT;
	}

	spin_lock_irqsave(&command_data->sp->lock, flags);
	if (command_data->command) {
		spin_unlock_irqrestore(&command_data->sp->lock, flags);
		command_put(cmd);
		return -EAGAIN;
	}
	command_data->command = cmd;
	spin_unlock_irqrestore(&command_data->sp->lock, flags);

	ibmasm_exec_command(command_data->sp, cmd);
	ibmasm_wait_for_response(cmd, get_dot_command_timeout(cmd->buffer));

	return count;
}

static int event_file_open(struct inode *inode, struct file *file)
{
	struct ibmasmfs_event_data *event_data;
	struct service_processor *sp;

	if (!inode->i_private)
		return -ENODEV;

	sp = inode->i_private;

	event_data = kmalloc(sizeof(struct ibmasmfs_event_data), GFP_KERNEL);
	if (!event_data)
		return -ENOMEM;

	ibmasm_event_reader_register(sp, &event_data->reader);

	event_data->sp = sp;
	event_data->active = 0;
	file->private_data = event_data;
	return 0;
}

static int event_file_close(struct inode *inode, struct file *file)
{
	struct ibmasmfs_event_data *event_data = file->private_data;

	ibmasm_event_reader_unregister(event_data->sp, &event_data->reader);
	kfree(event_data);
	return 0;
}

static ssize_t event_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
	struct ibmasmfs_event_data *event_data = file->private_data;
	struct event_reader *reader = &event_data->reader;
	struct service_processor *sp = event_data->sp;
	int ret;
	unsigned long flags;

	if (*offset < 0)
		return -EINVAL;
	if (count == 0 || count > IBMASM_EVENT_MAX_SIZE)
		return 0;
	if (*offset != 0)
		return 0;

	spin_lock_irqsave(&sp->lock, flags);
	if (event_data->active) {
		spin_unlock_irqrestore(&sp->lock, flags);
		return -EBUSY;
	}
	event_data->active = 1;
	spin_unlock_irqrestore(&sp->lock, flags);

	ret = ibmasm_get_next_event(sp, reader);
	if (ret <= 0)
		goto out;

	if (count < reader->data_size) {
		ret = -EINVAL;
		goto out;
	}

        if (copy_to_user(buf, reader->data, reader->data_size)) {
		ret = -EFAULT;
		goto out;
	}
	ret = reader->data_size;

out:
	event_data->active = 0;
	return ret;
}

static ssize_t event_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
{
	struct ibmasmfs_event_data *event_data = file->private_data;

	if (*offset < 0)
		return -EINVAL;
	if (count != 1)
		return 0;
	if (*offset != 0)
		return 0;

	ibmasm_cancel_next_event(&event_data->reader);
	return 0;
}

static int r_heartbeat_file_open(struct inode *inode, struct file *file)
{
	struct ibmasmfs_heartbeat_data *rhbeat;

	if (!inode->i_private)
		return -ENODEV;

	rhbeat = kmalloc(sizeof(struct ibmasmfs_heartbeat_data), GFP_KERNEL);
	if (!rhbeat)
		return -ENOMEM;

	rhbeat->sp = inode->i_private;
	rhbeat->active = 0;
	ibmasm_init_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
	file->private_data = rhbeat;
	return 0;
}

static int r_heartbeat_file_close(struct inode *inode, struct file *file)
{
	struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;

	kfree(rhbeat);
	return 0;
}

static ssize_t r_heartbeat_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
	struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
	unsigned long flags;
	int result;

	if (*offset < 0)
		return -EINVAL;
	if (count == 0 || count > 1024)
		return 0;
	if (*offset != 0)
		return 0;

	/* allow only one reverse heartbeat per process */
	spin_lock_irqsave(&rhbeat->sp->lock, flags);
	if (rhbeat->active) {
		spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
		return -EBUSY;
	}
	rhbeat->active = 1;
	spin_unlock_irqrestore(&rhbeat->sp->lock, flags);

	result = ibmasm_start_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
	rhbeat->active = 0;

	return result;
}

static ssize_t r_heartbeat_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
{
	struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;

	if (*offset < 0)
		return -EINVAL;
	if (count != 1)
		return 0;
	if (*offset != 0)
		return 0;

	if (rhbeat->active)
		ibmasm_stop_reverse_heartbeat(&rhbeat->heartbeat);

	return 1;
}

static int remote_settings_file_close(struct inode *inode, struct file *file)
{
	return 0;
}

static ssize_t remote_settings_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
{
	void __iomem *address = (void __iomem *)file->private_data;
	unsigned char *page;
	int retval;
	int len = 0;
	unsigned int value;

	if (*offset < 0)
		return -EINVAL;
	if (count == 0 || count > 1024)
		return 0;
	if (*offset != 0)
		return 0;

	page = (unsigned char *)__get_free_page(GFP_KERNEL);
	if (!page)
		return -ENOMEM;

	value = readl(address);
	len = sprintf(page, "%d\n", value);

	if (copy_to_user(buf, page, len)) {
		retval = -EFAULT;
		goto exit;
	}
	*offset += len;
	retval = len;

exit:
	free_page((unsigned long)page);
	return retval;
}

static ssize_t remote_settings_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
{
	void __iomem *address = (void __iomem *)file->private_data;
	char *buff;
	unsigned int value;

	if (*offset < 0)
		return -EINVAL;
	if (count == 0 || count > 1024)
		return 0;
	if (*offset != 0)
		return 0;

	buff = kzalloc (count + 1, GFP_KERNEL);
	if (!buff)
		return -ENOMEM;


	if (copy_from_user(buff, ubuff, count)) {
		kfree(buff);
		return -EFAULT;
	}

	value = simple_strtoul(buff, NULL, 10);
	writel(value, address);
	kfree(buff);

	return count;
}

static const struct file_operations command_fops = {
	.open =		command_file_open,
	.release =	command_file_close,
	.read =		command_file_read,
	.write =	command_file_write,
	.llseek =	generic_file_llseek,
};

static const struct file_operations event_fops = {
	.open =		event_file_open,
	.release =	event_file_close,
	.read =		event_file_read,
	.write =	event_file_write,
	.llseek =	generic_file_llseek,
};

static const struct file_operations r_heartbeat_fops = {
	.open =		r_heartbeat_file_open,
	.release =	r_heartbeat_file_close,
	.read =		r_heartbeat_file_read,
	.write =	r_heartbeat_file_write,
	.llseek =	generic_file_llseek,
};

static const struct file_operations remote_settings_fops = {
	.open =		simple_open,
	.release =	remote_settings_file_close,
	.read =		remote_settings_file_read,
	.write =	remote_settings_file_write,
	.llseek =	generic_file_llseek,
};


static void ibmasmfs_create_files (struct super_block *sb)
{
	struct list_head *entry;
	struct service_processor *sp;

	list_for_each(entry, &service_processors) {
		struct dentry *dir;
		struct dentry *remote_dir;
		sp = list_entry(entry, struct service_processor, node);
		dir = ibmasmfs_create_dir(sb, sb->s_root, sp->dirname);
		if (!dir)
			continue;

		ibmasmfs_create_file(sb, dir, "command", &command_fops, sp, S_IRUSR|S_IWUSR);
		ibmasmfs_create_file(sb, dir, "event", &event_fops, sp, S_IRUSR|S_IWUSR);
		ibmasmfs_create_file(sb, dir, "reverse_heartbeat", &r_heartbeat_fops, sp, S_IRUSR|S_IWUSR);

		remote_dir = ibmasmfs_create_dir(sb, dir, "remote_video");
		if (!remote_dir)
			continue;

		ibmasmfs_create_file(sb, remote_dir, "width", &remote_settings_fops, (void *)display_width(sp), S_IRUSR|S_IWUSR);
		ibmasmfs_create_file(sb, remote_dir, "height", &remote_settings_fops, (void *)display_height(sp), S_IRUSR|S_IWUSR);
		ibmasmfs_create_file(sb, remote_dir, "depth", &remote_settings_fops, (void *)display_depth(sp), S_IRUSR|S_IWUSR);
	}
}