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
74static LIST_HEAD(service_processors);
75
76static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode);
77static void ibmasmfs_create_files (struct super_block *sb);
78static int ibmasmfs_fill_super(struct super_block *sb, struct fs_context *fc);
79
80static int ibmasmfs_get_tree(struct fs_context *fc)
81{
82 return get_tree_single(fc, fill_super: ibmasmfs_fill_super);
83}
84
85static const struct fs_context_operations ibmasmfs_context_ops = {
86 .get_tree = ibmasmfs_get_tree,
87};
88
89static int ibmasmfs_init_fs_context(struct fs_context *fc)
90{
91 fc->ops = &ibmasmfs_context_ops;
92 return 0;
93}
94
95static const struct super_operations ibmasmfs_s_ops = {
96 .statfs = simple_statfs,
97 .drop_inode = generic_delete_inode,
98};
99
100static const struct file_operations *ibmasmfs_dir_ops = &simple_dir_operations;
101
102static struct file_system_type ibmasmfs_type = {
103 .owner = THIS_MODULE,
104 .name = "ibmasmfs",
105 .init_fs_context = ibmasmfs_init_fs_context,
106 .kill_sb = kill_litter_super,
107};
108MODULE_ALIAS_FS("ibmasmfs");
109
110static int ibmasmfs_fill_super(struct super_block *sb, struct fs_context *fc)
111{
112 struct inode *root;
113
114 sb->s_blocksize = PAGE_SIZE;
115 sb->s_blocksize_bits = PAGE_SHIFT;
116 sb->s_magic = IBMASMFS_MAGIC;
117 sb->s_op = &ibmasmfs_s_ops;
118 sb->s_time_gran = 1;
119
120 root = ibmasmfs_make_inode (sb, S_IFDIR | 0500);
121 if (!root)
122 return -ENOMEM;
123
124 root->i_op = &simple_dir_inode_operations;
125 root->i_fop = ibmasmfs_dir_ops;
126
127 sb->s_root = d_make_root(root);
128 if (!sb->s_root)
129 return -ENOMEM;
130
131 ibmasmfs_create_files(sb);
132 return 0;
133}
134
135static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode)
136{
137 struct inode *ret = new_inode(sb);
138
139 if (ret) {
140 ret->i_ino = get_next_ino();
141 ret->i_mode = mode;
142 simple_inode_init_ts(inode: ret);
143 }
144 return ret;
145}
146
147static struct dentry *ibmasmfs_create_file(struct dentry *parent,
148 const char *name,
149 const struct file_operations *fops,
150 void *data,
151 int mode)
152{
153 struct dentry *dentry;
154 struct inode *inode;
155
156 dentry = d_alloc_name(parent, name);
157 if (!dentry)
158 return NULL;
159
160 inode = ibmasmfs_make_inode(sb: parent->d_sb, S_IFREG | mode);
161 if (!inode) {
162 dput(dentry);
163 return NULL;
164 }
165
166 inode->i_fop = fops;
167 inode->i_private = data;
168
169 d_add(dentry, inode);
170 return dentry;
171}
172
173static struct dentry *ibmasmfs_create_dir(struct dentry *parent,
174 const char *name)
175{
176 struct dentry *dentry;
177 struct inode *inode;
178
179 dentry = d_alloc_name(parent, name);
180 if (!dentry)
181 return NULL;
182
183 inode = ibmasmfs_make_inode(sb: parent->d_sb, S_IFDIR | 0500);
184 if (!inode) {
185 dput(dentry);
186 return NULL;
187 }
188
189 inode->i_op = &simple_dir_inode_operations;
190 inode->i_fop = ibmasmfs_dir_ops;
191
192 d_add(dentry, inode);
193 return dentry;
194}
195
196int ibmasmfs_register(void)
197{
198 return register_filesystem(&ibmasmfs_type);
199}
200
201void ibmasmfs_unregister(void)
202{
203 unregister_filesystem(&ibmasmfs_type);
204}
205
206void ibmasmfs_add_sp(struct service_processor *sp)
207{
208 list_add(new: &sp->node, head: &service_processors);
209}
210
211/* struct to save state between command file operations */
212struct ibmasmfs_command_data {
213 struct service_processor *sp;
214 struct command *command;
215};
216
217/* struct to save state between event file operations */
218struct 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 */
225struct ibmasmfs_heartbeat_data {
226 struct service_processor *sp;
227 struct reverse_heartbeat heartbeat;
228 int active;
229};
230
231static 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(size: 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
248static 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(cmd: command_data->command);
254
255 kfree(objp: command_data);
256 return 0;
257}
258
259static 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(lock: &command_data->sp->lock, flags);
277 return 0;
278 }
279 command_data->command = NULL;
280 spin_unlock_irqrestore(lock: &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(to: buf, from: cmd->buffer, n: len)) {
288 command_put(cmd);
289 return -EFAULT;
290 }
291 command_put(cmd);
292
293 return len;
294}
295
296static 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(sp: command_data->sp, buffer_size: count);
314 if (!cmd)
315 return -ENOMEM;
316
317 if (copy_from_user(to: cmd->buffer, from: ubuff, n: 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(lock: &command_data->sp->lock, flags);
325 command_put(cmd);
326 return -EAGAIN;
327 }
328 command_data->command = cmd;
329 spin_unlock_irqrestore(lock: &command_data->sp->lock, flags);
330
331 ibmasm_exec_command(sp: command_data->sp, cmd);
332 ibmasm_wait_for_response(cmd, timeout: get_dot_command_timeout(buffer: cmd->buffer));
333
334 return count;
335}
336
337static 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(size: sizeof(struct ibmasmfs_event_data), GFP_KERNEL);
348 if (!event_data)
349 return -ENOMEM;
350
351 ibmasm_event_reader_register(sp, reader: &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
359static 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(sp: event_data->sp, reader: &event_data->reader);
364 kfree(objp: event_data);
365 return 0;
366}
367
368static 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(lock: &sp->lock, flags);
386 return -EBUSY;
387 }
388 event_data->active = 1;
389 spin_unlock_irqrestore(lock: &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(to: buf, from: reader->data, n: reader->data_size)) {
401 ret = -EFAULT;
402 goto out;
403 }
404 ret = reader->data_size;
405
406out:
407 event_data->active = 0;
408 return ret;
409}
410
411static 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(reader: &event_data->reader);
423 return 0;
424}
425
426static 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(size: 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(sp: rhbeat->sp, rhb: &rhbeat->heartbeat);
440 file->private_data = rhbeat;
441 return 0;
442}
443
444static int r_heartbeat_file_close(struct inode *inode, struct file *file)
445{
446 struct ibmasmfs_heartbeat_data *rhbeat = file->private_data;
447
448 kfree(objp: rhbeat);
449 return 0;
450}
451
452static 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(lock: &rhbeat->sp->lock, flags);
469 return -EBUSY;
470 }
471 rhbeat->active = 1;
472 spin_unlock_irqrestore(lock: &rhbeat->sp->lock, flags);
473
474 result = ibmasm_start_reverse_heartbeat(sp: rhbeat->sp, rhb: &rhbeat->heartbeat);
475 rhbeat->active = 0;
476
477 return result;
478}
479
480static 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(rhb: &rhbeat->heartbeat);
493
494 return 1;
495}
496
497static int remote_settings_file_close(struct inode *inode, struct file *file)
498{
499 return 0;
500}
501
502static 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(addr: address);
510 len = snprintf(buf: lbuf, size: sizeof(lbuf), fmt: "%d\n", value);
511
512 return simple_read_from_buffer(to: buf, count, ppos: offset, from: lbuf, available: len);
513}
514
515static 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 = kzalloc (size: count + 1, GFP_KERNEL);
529 if (!buff)
530 return -ENOMEM;
531
532
533 if (copy_from_user(to: buff, from: ubuff, n: count)) {
534 kfree(objp: buff);
535 return -EFAULT;
536 }
537
538 value = simple_strtoul(buff, NULL, 10);
539 writel(val: value, addr: address);
540 kfree(objp: buff);
541
542 return count;
543}
544
545static const struct file_operations command_fops = {
546 .open = command_file_open,
547 .release = command_file_close,
548 .read = command_file_read,
549 .write = command_file_write,
550 .llseek = generic_file_llseek,
551};
552
553static const struct file_operations event_fops = {
554 .open = event_file_open,
555 .release = event_file_close,
556 .read = event_file_read,
557 .write = event_file_write,
558 .llseek = generic_file_llseek,
559};
560
561static const struct file_operations r_heartbeat_fops = {
562 .open = r_heartbeat_file_open,
563 .release = r_heartbeat_file_close,
564 .read = r_heartbeat_file_read,
565 .write = r_heartbeat_file_write,
566 .llseek = generic_file_llseek,
567};
568
569static const struct file_operations remote_settings_fops = {
570 .open = simple_open,
571 .release = remote_settings_file_close,
572 .read = remote_settings_file_read,
573 .write = remote_settings_file_write,
574 .llseek = generic_file_llseek,
575};
576
577
578static void ibmasmfs_create_files (struct super_block *sb)
579{
580 struct list_head *entry;
581 struct service_processor *sp;
582
583 list_for_each(entry, &service_processors) {
584 struct dentry *dir;
585 struct dentry *remote_dir;
586 sp = list_entry(entry, struct service_processor, node);
587 dir = ibmasmfs_create_dir(parent: sb->s_root, name: sp->dirname);
588 if (!dir)
589 continue;
590
591 ibmasmfs_create_file(parent: dir, name: "command", fops: &command_fops, data: sp, S_IRUSR|S_IWUSR);
592 ibmasmfs_create_file(parent: dir, name: "event", fops: &event_fops, data: sp, S_IRUSR|S_IWUSR);
593 ibmasmfs_create_file(parent: dir, name: "reverse_heartbeat", fops: &r_heartbeat_fops, data: sp, S_IRUSR|S_IWUSR);
594
595 remote_dir = ibmasmfs_create_dir(parent: dir, name: "remote_video");
596 if (!remote_dir)
597 continue;
598
599 ibmasmfs_create_file(parent: remote_dir, name: "width", fops: &remote_settings_fops, data: (void *)display_width(sp), S_IRUSR|S_IWUSR);
600 ibmasmfs_create_file(parent: remote_dir, name: "height", fops: &remote_settings_fops, data: (void *)display_height(sp), S_IRUSR|S_IWUSR);
601 ibmasmfs_create_file(parent: remote_dir, name: "depth", fops: &remote_settings_fops, data: (void *)display_depth(sp), S_IRUSR|S_IWUSR);
602 }
603}
604

source code of linux/drivers/misc/ibmasm/ibmasmfs.c