1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * IBM ASM Service Processor Device Driver
4 *
5 * Copyright (C) IBM Corporation, 2004
6 *
7 * Author: Max Asböck <amax@us.ibm.com>
8 */
9
10 /*
11 * Parts of this code are based on an article by Jonathan Corbet
12 * that appeared in Linux Weekly News.
13 */
14
15
16 /*
17 * The IBMASM file virtual filesystem. It creates the following hierarchy
18 * dynamically when mounted from user space:
19 *
20 * /ibmasm
21 * |-- 0
22 * | |-- command
23 * | |-- event
24 * | |-- reverse_heartbeat
25 * | `-- remote_video
26 * | |-- depth
27 * | |-- height
28 * | `-- width
29 * .
30 * .
31 * .
32 * `-- n
33 * |-- command
34 * |-- event
35 * |-- reverse_heartbeat
36 * `-- remote_video
37 * |-- depth
38 * |-- height
39 * `-- width
40 *
41 * For each service processor the following files are created:
42 *
43 * command: execute dot commands
44 * write: execute a dot command on the service processor
45 * read: return the result of a previously executed dot command
46 *
47 * events: listen for service processor events
48 * read: sleep (interruptible) until an event occurs
49 * write: wakeup sleeping event listener
50 *
51 * reverse_heartbeat: send a heartbeat to the service processor
52 * read: sleep (interruptible) until the reverse heartbeat fails
53 * write: wakeup sleeping heartbeat listener
54 *
55 * remote_video/width
56 * remote_video/height
57 * remote_video/width: control remote display settings
58 * write: set value
59 * read: read value
60 */
61
62 #include <linux/fs.h>
63 #include <linux/fs_context.h>
64 #include <linux/pagemap.h>
65 #include <linux/slab.h>
66 #include <linux/uaccess.h>
67 #include <asm/io.h>
68 #include "ibmasm.h"
69 #include "remote.h"
70 #include "dot_command.h"
71
72 #define IBMASMFS_MAGIC 0x66726f67
73
74 static LIST_HEAD(service_processors);
75
76 static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode);
77 static void ibmasmfs_create_files (struct super_block *sb);
78 static int ibmasmfs_fill_super(struct super_block *sb, struct fs_context *fc);
79
ibmasmfs_get_tree(struct fs_context * fc)80 static int ibmasmfs_get_tree(struct fs_context *fc)
81 {
82 return get_tree_single(fc, ibmasmfs_fill_super);
83 }
84
85 static const struct fs_context_operations ibmasmfs_context_ops = {
86 .get_tree = ibmasmfs_get_tree,
87 };
88
ibmasmfs_init_fs_context(struct fs_context * fc)89 static int ibmasmfs_init_fs_context(struct fs_context *fc)
90 {
91 fc->ops = &ibmasmfs_context_ops;
92 return 0;
93 }
94
95 static const struct super_operations ibmasmfs_s_ops = {
96 .statfs = simple_statfs,
97 .drop_inode = inode_just_drop,
98 };
99
100 static struct file_system_type ibmasmfs_type = {
101 .owner = THIS_MODULE,
102 .name = "ibmasmfs",
103 .init_fs_context = ibmasmfs_init_fs_context,
104 .kill_sb = kill_anon_super,
105 };
106 MODULE_ALIAS_FS("ibmasmfs");
107
ibmasmfs_fill_super(struct super_block * sb,struct fs_context * fc)108 static int ibmasmfs_fill_super(struct super_block *sb, struct fs_context *fc)
109 {
110 struct inode *root;
111
112 sb->s_blocksize = PAGE_SIZE;
113 sb->s_blocksize_bits = PAGE_SHIFT;
114 sb->s_magic = IBMASMFS_MAGIC;
115 sb->s_op = &ibmasmfs_s_ops;
116 sb->s_time_gran = 1;
117
118 root = ibmasmfs_make_inode (sb, S_IFDIR | 0500);
119 if (!root)
120 return -ENOMEM;
121
122 root->i_op = &simple_dir_inode_operations;
123 root->i_fop = &simple_dir_operations;
124
125 sb->s_root = d_make_root(root);
126 if (!sb->s_root)
127 return -ENOMEM;
128
129 ibmasmfs_create_files(sb);
130 return 0;
131 }
132
ibmasmfs_make_inode(struct super_block * sb,int mode)133 static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode)
134 {
135 struct inode *ret = new_inode(sb);
136
137 if (ret) {
138 ret->i_ino = get_next_ino();
139 ret->i_mode = mode;
140 simple_inode_init_ts(ret);
141 }
142 return ret;
143 }
144
ibmasmfs_create_file(struct dentry * parent,const char * name,const struct file_operations * fops,void * data,int mode)145 static int ibmasmfs_create_file(struct dentry *parent,
146 const char *name,
147 const struct file_operations *fops,
148 void *data,
149 int mode)
150 {
151 struct dentry *dentry;
152 struct inode *inode;
153
154 dentry = d_alloc_name(parent, name);
155 if (!dentry)
156 return -ENOMEM;
157
158 inode = ibmasmfs_make_inode(parent->d_sb, S_IFREG | mode);
159 if (!inode) {
160 dput(dentry);
161 return -ENOMEM;
162 }
163
164 inode->i_fop = fops;
165 inode->i_private = data;
166
167 d_make_persistent(dentry, inode);
168 dput(dentry);
169 return 0;
170 }
171
ibmasmfs_create_dir(struct dentry * parent,const char * name)172 static struct dentry *ibmasmfs_create_dir(struct dentry *parent,
173 const char *name)
174 {
175 struct dentry *dentry;
176 struct inode *inode;
177
178 dentry = d_alloc_name(parent, name);
179 if (!dentry)
180 return NULL;
181
182 inode = ibmasmfs_make_inode(parent->d_sb, S_IFDIR | 0500);
183 if (!inode) {
184 dput(dentry);
185 return NULL;
186 }
187
188 inode->i_op = &simple_dir_inode_operations;
189 inode->i_fop = &simple_dir_operations;
190
191 d_make_persistent(dentry, inode);
192 dput(dentry);
193 return dentry; // borrowed
194 }
195
ibmasmfs_register(void)196 int ibmasmfs_register(void)
197 {
198 return register_filesystem(&ibmasmfs_type);
199 }
200
ibmasmfs_unregister(void)201 void ibmasmfs_unregister(void)
202 {
203 unregister_filesystem(&ibmasmfs_type);
204 }
205
ibmasmfs_add_sp(struct service_processor * sp)206 void ibmasmfs_add_sp(struct service_processor *sp)
207 {
208 list_add(&sp->node, &service_processors);
209 }
210
211 /* struct to save state between command file operations */
212 struct ibmasmfs_command_data {
213 struct service_processor *sp;
214 struct command *command;
215 };
216
217 /* struct to save state between event file operations */
218 struct ibmasmfs_event_data {
219 struct service_processor *sp;
220 struct event_reader reader;
221 int active;
222 };
223
224 /* struct to save state between reverse heartbeat file operations */
225 struct ibmasmfs_heartbeat_data {
226 struct service_processor *sp;
227 struct reverse_heartbeat heartbeat;
228 int active;
229 };
230
command_file_open(struct inode * inode,struct file * file)231 static int command_file_open(struct inode *inode, struct file *file)
232 {
233 struct ibmasmfs_command_data *command_data;
234
235 if (!inode->i_private)
236 return -ENODEV;
237
238 command_data = kmalloc(sizeof(struct ibmasmfs_command_data), GFP_KERNEL);
239 if (!command_data)
240 return -ENOMEM;
241
242 command_data->command = NULL;
243 command_data->sp = inode->i_private;
244 file->private_data = command_data;
245 return 0;
246 }
247
command_file_close(struct inode * inode,struct file * file)248 static int command_file_close(struct inode *inode, struct file *file)
249 {
250 struct ibmasmfs_command_data *command_data = file->private_data;
251
252 if (command_data->command)
253 command_put(command_data->command);
254
255 kfree(command_data);
256 return 0;
257 }
258
command_file_read(struct file * file,char __user * buf,size_t count,loff_t * offset)259 static ssize_t command_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
260 {
261 struct ibmasmfs_command_data *command_data = file->private_data;
262 struct command *cmd;
263 int len;
264 unsigned long flags;
265
266 if (*offset < 0)
267 return -EINVAL;
268 if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
269 return 0;
270 if (*offset != 0)
271 return 0;
272
273 spin_lock_irqsave(&command_data->sp->lock, flags);
274 cmd = command_data->command;
275 if (cmd == NULL) {
276 spin_unlock_irqrestore(&command_data->sp->lock, flags);
277 return 0;
278 }
279 command_data->command = NULL;
280 spin_unlock_irqrestore(&command_data->sp->lock, flags);
281
282 if (cmd->status != IBMASM_CMD_COMPLETE) {
283 command_put(cmd);
284 return -EIO;
285 }
286 len = min(count, cmd->buffer_size);
287 if (copy_to_user(buf, cmd->buffer, len)) {
288 command_put(cmd);
289 return -EFAULT;
290 }
291 command_put(cmd);
292
293 return len;
294 }
295
command_file_write(struct file * file,const char __user * ubuff,size_t count,loff_t * offset)296 static ssize_t command_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
297 {
298 struct ibmasmfs_command_data *command_data = file->private_data;
299 struct command *cmd;
300 unsigned long flags;
301
302 if (*offset < 0)
303 return -EINVAL;
304 if (count == 0 || count > IBMASM_CMD_MAX_BUFFER_SIZE)
305 return 0;
306 if (*offset != 0)
307 return 0;
308
309 /* commands are executed sequentially, only one command at a time */
310 if (command_data->command)
311 return -EAGAIN;
312
313 cmd = ibmasm_new_command(command_data->sp, count);
314 if (!cmd)
315 return -ENOMEM;
316
317 if (copy_from_user(cmd->buffer, ubuff, count)) {
318 command_put(cmd);
319 return -EFAULT;
320 }
321
322 spin_lock_irqsave(&command_data->sp->lock, flags);
323 if (command_data->command) {
324 spin_unlock_irqrestore(&command_data->sp->lock, flags);
325 command_put(cmd);
326 return -EAGAIN;
327 }
328 command_data->command = cmd;
329 spin_unlock_irqrestore(&command_data->sp->lock, flags);
330
331 ibmasm_exec_command(command_data->sp, cmd);
332 ibmasm_wait_for_response(cmd, get_dot_command_timeout(cmd->buffer));
333
334 return count;
335 }
336
event_file_open(struct inode * inode,struct file * file)337 static int event_file_open(struct inode *inode, struct file *file)
338 {
339 struct ibmasmfs_event_data *event_data;
340 struct service_processor *sp;
341
342 if (!inode->i_private)
343 return -ENODEV;
344
345 sp = inode->i_private;
346
347 event_data = kmalloc(sizeof(struct ibmasmfs_event_data), GFP_KERNEL);
348 if (!event_data)
349 return -ENOMEM;
350
351 ibmasm_event_reader_register(sp, &event_data->reader);
352
353 event_data->sp = sp;
354 event_data->active = 0;
355 file->private_data = event_data;
356 return 0;
357 }
358
event_file_close(struct inode * inode,struct file * file)359 static int event_file_close(struct inode *inode, struct file *file)
360 {
361 struct ibmasmfs_event_data *event_data = file->private_data;
362
363 ibmasm_event_reader_unregister(event_data->sp, &event_data->reader);
364 kfree(event_data);
365 return 0;
366 }
367
event_file_read(struct file * file,char __user * buf,size_t count,loff_t * offset)368 static ssize_t event_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
369 {
370 struct ibmasmfs_event_data *event_data = file->private_data;
371 struct event_reader *reader = &event_data->reader;
372 struct service_processor *sp = event_data->sp;
373 int ret;
374 unsigned long flags;
375
376 if (*offset < 0)
377 return -EINVAL;
378 if (count == 0 || count > IBMASM_EVENT_MAX_SIZE)
379 return 0;
380 if (*offset != 0)
381 return 0;
382
383 spin_lock_irqsave(&sp->lock, flags);
384 if (event_data->active) {
385 spin_unlock_irqrestore(&sp->lock, flags);
386 return -EBUSY;
387 }
388 event_data->active = 1;
389 spin_unlock_irqrestore(&sp->lock, flags);
390
391 ret = ibmasm_get_next_event(sp, reader);
392 if (ret <= 0)
393 goto out;
394
395 if (count < reader->data_size) {
396 ret = -EINVAL;
397 goto out;
398 }
399
400 if (copy_to_user(buf, reader->data, reader->data_size)) {
401 ret = -EFAULT;
402 goto out;
403 }
404 ret = reader->data_size;
405
406 out:
407 event_data->active = 0;
408 return ret;
409 }
410
event_file_write(struct file * file,const char __user * buf,size_t count,loff_t * offset)411 static ssize_t event_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
412 {
413 struct ibmasmfs_event_data *event_data = file->private_data;
414
415 if (*offset < 0)
416 return -EINVAL;
417 if (count != 1)
418 return 0;
419 if (*offset != 0)
420 return 0;
421
422 ibmasm_cancel_next_event(&event_data->reader);
423 return 0;
424 }
425
r_heartbeat_file_open(struct inode * inode,struct file * file)426 static int r_heartbeat_file_open(struct inode *inode, struct file *file)
427 {
428 struct ibmasmfs_heartbeat_data *rhbeat;
429
430 if (!inode->i_private)
431 return -ENODEV;
432
433 rhbeat = kmalloc(sizeof(struct ibmasmfs_heartbeat_data), GFP_KERNEL);
434 if (!rhbeat)
435 return -ENOMEM;
436
437 rhbeat->sp = inode->i_private;
438 rhbeat->active = 0;
439 ibmasm_init_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
440 file->private_data = rhbeat;
441 return 0;
442 }
443
r_heartbeat_file_close(struct inode * inode,struct file * file)444 static int r_heartbeat_file_close(struct inode *inode, struct file *file)
445 {
446 struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
447
448 kfree(rhbeat);
449 return 0;
450 }
451
r_heartbeat_file_read(struct file * file,char __user * buf,size_t count,loff_t * offset)452 static ssize_t r_heartbeat_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
453 {
454 struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
455 unsigned long flags;
456 int result;
457
458 if (*offset < 0)
459 return -EINVAL;
460 if (count == 0 || count > 1024)
461 return 0;
462 if (*offset != 0)
463 return 0;
464
465 /* allow only one reverse heartbeat per process */
466 spin_lock_irqsave(&rhbeat->sp->lock, flags);
467 if (rhbeat->active) {
468 spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
469 return -EBUSY;
470 }
471 rhbeat->active = 1;
472 spin_unlock_irqrestore(&rhbeat->sp->lock, flags);
473
474 result = ibmasm_start_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
475 rhbeat->active = 0;
476
477 return result;
478 }
479
r_heartbeat_file_write(struct file * file,const char __user * buf,size_t count,loff_t * offset)480 static ssize_t r_heartbeat_file_write(struct file *file, const char __user *buf, size_t count, loff_t *offset)
481 {
482 struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
483
484 if (*offset < 0)
485 return -EINVAL;
486 if (count != 1)
487 return 0;
488 if (*offset != 0)
489 return 0;
490
491 if (rhbeat->active)
492 ibmasm_stop_reverse_heartbeat(&rhbeat->heartbeat);
493
494 return 1;
495 }
496
remote_settings_file_close(struct inode * inode,struct file * file)497 static int remote_settings_file_close(struct inode *inode, struct file *file)
498 {
499 return 0;
500 }
501
remote_settings_file_read(struct file * file,char __user * buf,size_t count,loff_t * offset)502 static ssize_t remote_settings_file_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
503 {
504 void __iomem *address = (void __iomem *)file->private_data;
505 int len = 0;
506 unsigned int value;
507 char lbuf[20];
508
509 value = readl(address);
510 len = snprintf(lbuf, sizeof(lbuf), "%d\n", value);
511
512 return simple_read_from_buffer(buf, count, offset, lbuf, len);
513 }
514
remote_settings_file_write(struct file * file,const char __user * ubuff,size_t count,loff_t * offset)515 static ssize_t remote_settings_file_write(struct file *file, const char __user *ubuff, size_t count, loff_t *offset)
516 {
517 void __iomem *address = (void __iomem *)file->private_data;
518 char *buff;
519 unsigned int value;
520
521 if (*offset < 0)
522 return -EINVAL;
523 if (count == 0 || count > 1024)
524 return 0;
525 if (*offset != 0)
526 return 0;
527
528 buff = memdup_user_nul(ubuff, count);
529 if (IS_ERR(buff))
530 return PTR_ERR(buff);
531
532 value = simple_strtoul(buff, NULL, 10);
533 writel(value, address);
534 kfree(buff);
535
536 return count;
537 }
538
539 static const struct file_operations command_fops = {
540 .open = command_file_open,
541 .release = command_file_close,
542 .read = command_file_read,
543 .write = command_file_write,
544 .llseek = generic_file_llseek,
545 };
546
547 static const struct file_operations event_fops = {
548 .open = event_file_open,
549 .release = event_file_close,
550 .read = event_file_read,
551 .write = event_file_write,
552 .llseek = generic_file_llseek,
553 };
554
555 static const struct file_operations r_heartbeat_fops = {
556 .open = r_heartbeat_file_open,
557 .release = r_heartbeat_file_close,
558 .read = r_heartbeat_file_read,
559 .write = r_heartbeat_file_write,
560 .llseek = generic_file_llseek,
561 };
562
563 static const struct file_operations remote_settings_fops = {
564 .open = simple_open,
565 .release = remote_settings_file_close,
566 .read = remote_settings_file_read,
567 .write = remote_settings_file_write,
568 .llseek = generic_file_llseek,
569 };
570
571
ibmasmfs_create_files(struct super_block * sb)572 static void ibmasmfs_create_files (struct super_block *sb)
573 {
574 struct list_head *entry;
575 struct service_processor *sp;
576
577 list_for_each(entry, &service_processors) {
578 struct dentry *dir;
579 struct dentry *remote_dir;
580 sp = list_entry(entry, struct service_processor, node);
581 dir = ibmasmfs_create_dir(sb->s_root, sp->dirname);
582 if (!dir)
583 continue;
584
585 ibmasmfs_create_file(dir, "command", &command_fops, sp, S_IRUSR|S_IWUSR);
586 ibmasmfs_create_file(dir, "event", &event_fops, sp, S_IRUSR|S_IWUSR);
587 ibmasmfs_create_file(dir, "reverse_heartbeat", &r_heartbeat_fops, sp, S_IRUSR|S_IWUSR);
588
589 remote_dir = ibmasmfs_create_dir(dir, "remote_video");
590 if (!remote_dir)
591 continue;
592
593 ibmasmfs_create_file(remote_dir, "width", &remote_settings_fops, (void *)display_width(sp), S_IRUSR|S_IWUSR);
594 ibmasmfs_create_file(remote_dir, "height", &remote_settings_fops, (void *)display_height(sp), S_IRUSR|S_IWUSR);
595 ibmasmfs_create_file(remote_dir, "depth", &remote_settings_fops, (void *)display_depth(sp), S_IRUSR|S_IWUSR);
596 }
597 }
598