1 /*
2 * linux/kernel/resource.c
3 *
4 * Copyright (C) 1999 Linus Torvalds
5 * Copyright (C) 1999 Martin Mares <mj@ucw.cz>
6 *
7 * Arbitrary resource management.
8 */
9
10 #include <linux/config.h>
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/errno.h>
14 #include <linux/ioport.h>
15 #include <linux/init.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18 #include <linux/fs.h>
19 #include <linux/proc_fs.h>
20 #include <linux/seq_file.h>
21 #include <asm/io.h>
22
23
24 struct resource ioport_resource = {
25 .name = "PCI IO",
26 .start = 0x0000,
27 .end = IO_SPACE_LIMIT,
28 .flags = IORESOURCE_IO,
29 };
30
31 EXPORT_SYMBOL(ioport_resource);
32
33 struct resource iomem_resource = {
34 .name = "PCI mem",
35 .start = 0UL,
36 .end = ~0UL,
37 .flags = IORESOURCE_MEM,
38 };
39
40 EXPORT_SYMBOL(iomem_resource);
41
42 static DEFINE_RWLOCK(resource_lock);
43
44 #ifdef CONFIG_PROC_FS
45
46 enum { MAX_IORES_LEVEL = 5 };
47
48 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
49 {
50 struct resource *p = v;
51 (*pos)++;
52 if (p->child)
53 return p->child;
54 while (!p->sibling && p->parent)
55 p = p->parent;
56 return p->sibling;
57 }
58
59 static void *r_start(struct seq_file *m, loff_t *pos)
60 __acquires(resource_lock)
61 {
62 struct resource *p = m->private;
63 loff_t l = 0;
64 read_lock(&resource_lock);
65 for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
66 ;
67 return p;
68 }
69
70 static void r_stop(struct seq_file *m, void *v)
71 __releases(resource_lock)
72 {
73 read_unlock(&resource_lock);
74 }
75
76 static int r_show(struct seq_file *m, void *v)
77 {
78 struct resource *root = m->private;
79 struct resource *r = v, *p;
80 int width = root->end < 0x10000 ? 4 : 8;
81 int depth;
82
83 for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
84 if (p->parent == root)
85 break;
86 seq_printf(m, "%*s%0*lx-%0*lx : %s\n",
87 depth * 2, "",
88 width, r->start,
89 width, r->end,
90 r->name ? r->name : "<BAD>");
91 return 0;
92 }
93
94 static struct seq_operations resource_op = {
95 .start = r_start,
96 .next = r_next,
97 .stop = r_stop,
98 .show = r_show,
99 };
100
101 static int ioports_open(struct inode *inode, struct file *file)
102 {
103 int res = seq_open(file, &resource_op);
104 if (!res) {
105 struct seq_file *m = file->private_data;
106 m->private = &ioport_resource;
107 }
108 return res;
109 }
110
111 static int iomem_open(struct inode *inode, struct file *file)
112 {
113 int res = seq_open(file, &resource_op);
114 if (!res) {
115 struct seq_file *m = file->private_data;
116 m->private = &iomem_resource;
117 }
118 return res;
119 }
120
121 static struct file_operations proc_ioports_operations = {
122 .open = ioports_open,
123 .read = seq_read,
124 .llseek = seq_lseek,
125 .release = seq_release,
126 };
127
128 static struct file_operations proc_iomem_operations = {
129 .open = iomem_open,
130 .read = seq_read,
131 .llseek = seq_lseek,
132 .release = seq_release,
133 };
134
135 static int __init ioresources_init(void)
136 {
137 struct proc_dir_entry *entry;
138
139 entry = create_proc_entry("ioports", 0, NULL);
140 if (entry)
141 entry->proc_fops = &proc_ioports_operations;
142 entry = create_proc_entry("iomem", 0, NULL);
143 if (entry)
144 entry->proc_fops = &proc_iomem_operations;
145 return 0;
146 }
147 __initcall(ioresources_init);
148
149 #endif /* CONFIG_PROC_FS */
150
151 /* Return the conflict entry if you can't request it */
152 static struct resource * __request_resource(struct resource *root, struct resource *new)
153 {
154 unsigned long start = new->start;
155 unsigned long end = new->end;
156 struct resource *tmp, **p;
157
158 if (end < start)
159 return root;
160 if (start < root->start)
161 return root;
162 if (end > root->end)
163 return root;
164 p = &root->child;
165 for (;;) {
166 tmp = *p;
167 if (!tmp || tmp->start > end) {
168 new->sibling = tmp;
169 *p = new;
170 new->parent = root;
171 return NULL;
172 }
173 p = &tmp->sibling;
174 if (tmp->end < start)
175 continue;
176 return tmp;
177 }
178 }
179
180 static int __release_resource(struct resource *old)
181 {
182 struct resource *tmp, **p;
183
184 p = &old->parent->child;
185 for (;;) {
186 tmp = *p;
187 if (!tmp)
188 break;
189 if (tmp == old) {
190 *p = tmp->sibling;
191 old->parent = NULL;
192 return 0;
193 }
194 p = &tmp->sibling;
195 }
196 return -EINVAL;
197 }
198
199 int request_resource(struct resource *root, struct resource *new)
200 {
201 struct resource *conflict;
202
203 write_lock(&resource_lock);
204 conflict = __request_resource(root, new);
205 write_unlock(&resource_lock);
206 return conflict ? -EBUSY : 0;
207 }
208
209 EXPORT_SYMBOL(request_resource);
210
211 struct resource *____request_resource(struct resource *root, struct resource *new)
212 {
213 struct resource *conflict;
214
215 write_lock(&resource_lock);
216 conflict = __request_resource(root, new);
217 write_unlock(&resource_lock);
218 return conflict;
219 }
220
221 EXPORT_SYMBOL(____request_resource);
222
223 int release_resource(struct resource *old)
224 {
225 int retval;
226
227 write_lock(&resource_lock);
228 retval = __release_resource(old);
229 write_unlock(&resource_lock);
230 return retval;
231 }
232
233 EXPORT_SYMBOL(release_resource);
234
235 /*
236 * Find empty slot in the resource tree given range and alignment.
237 */
238 static int find_resource(struct resource *root, struct resource *new,
239 unsigned long size,
240 unsigned long min, unsigned long max,
241 unsigned long align,
242 void (*alignf)(void *, struct resource *,
243 unsigned long, unsigned long),
244 void *alignf_data)
245 {
246 struct resource *this = root->child;
247
248 new->start = root->start;
249 /*
250 * Skip past an allocated resource that starts at 0, since the assignment
251 * of this->start - 1 to new->end below would cause an underflow.
252 */
253 if (this && this->start == 0) {
254 new->start = this->end + 1;
255 this = this->sibling;
256 }
257 for(;;) {
258 if (this)
259 new->end = this->start - 1;
260 else
261 new->end = root->end;
262 if (new->start < min)
263 new->start = min;
264 if (new->end > max)
265 new->end = max;
266 new->start = ALIGN(new->start, align);
267 if (alignf)
268 alignf(alignf_data, new, size, align);
269 if (new->start < new->end && new->end - new->start >= size - 1) {
270 new->end = new->start + size - 1;
271 return 0;
272 }
273 if (!this)
274 break;
275 new->start = this->end + 1;
276 this = this->sibling;
277 }
278 return -EBUSY;
279 }
280
281 /*
282 * Allocate empty slot in the resource tree given range and alignment.
283 */
284 int allocate_resource(struct resource *root, struct resource *new,
285 unsigned long size,
286 unsigned long min, unsigned long max,
287 unsigned long align,
288 void (*alignf)(void *, struct resource *,
289 unsigned long, unsigned long),
290 void *alignf_data)
291 {
292 int err;
293
294 write_lock(&resource_lock);
295 err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
296 if (err >= 0 && __request_resource(root, new))
297 err = -EBUSY;
298 write_unlock(&resource_lock);
299 return err;
300 }
301
302 EXPORT_SYMBOL(allocate_resource);
303
304 /**
305 * insert_resource - Inserts a resource in the resource tree
306 * @parent: parent of the new resource
307 * @new: new resource to insert
308 *
309 * Returns 0 on success, -EBUSY if the resource can't be inserted.
310 *
311 * This function is equivalent of request_resource when no conflict
312 * happens. If a conflict happens, and the conflicting resources
313 * entirely fit within the range of the new resource, then the new
314 * resource is inserted and the conflicting resources become childs of
315 * the new resource. Otherwise the new resource becomes the child of
316 * the conflicting resource
317 */
318 int insert_resource(struct resource *parent, struct resource *new)
319 {
320 int result;
321 struct resource *first, *next;
322
323 write_lock(&resource_lock);
324 begin:
325 result = 0;
326 first = __request_resource(parent, new);
327 if (!first)
328 goto out;
329
330 result = -EBUSY;
331 if (first == parent)
332 goto out;
333
334 /* Resource fully contained by the clashing resource? Recurse into it */
335 if (first->start <= new->start && first->end >= new->end) {
336 parent = first;
337 goto begin;
338 }
339
340 for (next = first; ; next = next->sibling) {
341 /* Partial overlap? Bad, and unfixable */
342 if (next->start < new->start || next->end > new->end)
343 goto out;
344 if (!next->sibling)
345 break;
346 if (next->sibling->start > new->end)
347 break;
348 }
349
350 result = 0;
351
352 new->parent = parent;
353 new->sibling = next->sibling;
354 new->child = first;
355
356 next->sibling = NULL;
357 for (next = first; next; next = next->sibling)
358 next->parent = new;
359
360 if (parent->child == first) {
361 parent->child = new;
362 } else {
363 next = parent->child;
364 while (next->sibling != first)
365 next = next->sibling;
366 next->sibling = new;
367 }
368
369 out:
370 write_unlock(&resource_lock);
371 return result;
372 }
373
374 EXPORT_SYMBOL(insert_resource);
375
376 /*
377 * Given an existing resource, change its start and size to match the
378 * arguments. Returns -EBUSY if it can't fit. Existing children of
379 * the resource are assumed to be immutable.
380 */
381 int adjust_resource(struct resource *res, unsigned long start, unsigned long size)
382 {
383 struct resource *tmp, *parent = res->parent;
384 unsigned long end = start + size - 1;
385 int result = -EBUSY;
386
387 write_lock(&resource_lock);
388
389 if ((start < parent->start) || (end > parent->end))
390 goto out;
391
392 for (tmp = res->child; tmp; tmp = tmp->sibling) {
393 if ((tmp->start < start) || (tmp->end > end))
394 goto out;
395 }
396
397 if (res->sibling && (res->sibling->start <= end))
398 goto out;
399
400 tmp = parent->child;
401 if (tmp != res) {
402 while (tmp->sibling != res)
403 tmp = tmp->sibling;
404 if (start <= tmp->end)
405 goto out;
406 }
407
408 res->start = start;
409 res->end = end;
410 result = 0;
411
412 out:
413 write_unlock(&resource_lock);
414 return result;
415 }
416
417 EXPORT_SYMBOL(adjust_resource);
418
419 /*
420 * This is compatibility stuff for IO resources.
421 *
422 * Note how this, unlike the above, knows about
423 * the IO flag meanings (busy etc).
424 *
425 * Request-region creates a new busy region.
426 *
427 * Check-region returns non-zero if the area is already busy
428 *
429 * Release-region releases a matching busy region.
430 */
431 struct resource * __request_region(struct resource *parent, unsigned long start, unsigned long n, const char *name)
432 {
433 struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
434
435 if (res) {
436 res->name = name;
437 res->start = start;
438 res->end = start + n - 1;
439 res->flags = IORESOURCE_BUSY;
440
441 write_lock(&resource_lock);
442
443 for (;;) {
444 struct resource *conflict;
445
446 conflict = __request_resource(parent, res);
447 if (!conflict)
448 break;
449 if (conflict != parent) {
450 parent = conflict;
451 if (!(conflict->flags & IORESOURCE_BUSY))
452 continue;
453 }
454
455 /* Uhhuh, that didn't work out.. */
456 kfree(res);
457 res = NULL;
458 break;
459 }
460 write_unlock(&resource_lock);
461 }
462 return res;
463 }
464
465 EXPORT_SYMBOL(__request_region);
466
467 int __check_region(struct resource *parent, unsigned long start, unsigned long n)
468 {
469 struct resource * res;
470
471 res = __request_region(parent, start, n, "check-region");
472 if (!res)
473 return -EBUSY;
474
475 release_resource(res);
476 kfree(res);
477 return 0;
478 }
479
480 EXPORT_SYMBOL(__check_region);
481
482 void __release_region(struct resource *parent, unsigned long start, unsigned long n)
483 {
484 struct resource **p;
485 unsigned long end;
486
487 p = &parent->child;
488 end = start + n - 1;
489
490 write_lock(&resource_lock);
491
492 for (;;) {
493 struct resource *res = *p;
494
495 if (!res)
496 break;
497 if (res->start <= start && res->end >= end) {
498 if (!(res->flags & IORESOURCE_BUSY)) {
499 p = &res->child;
500 continue;
501 }
502 if (res->start != start || res->end != end)
503 break;
504 *p = res->sibling;
505 write_unlock(&resource_lock);
506 kfree(res);
507 return;
508 }
509 p = &res->sibling;
510 }
511
512 write_unlock(&resource_lock);
513
514 printk(KERN_WARNING "Trying to free nonexistent resource <%08lx-%08lx>\n", start, end);
515 }
516
517 EXPORT_SYMBOL(__release_region);
518
519 /*
520 * Called from init/main.c to reserve IO ports.
521 */
522 #define MAXRESERVE 4
523 static int __init reserve_setup(char *str)
524 {
525 static int reserved;
526 static struct resource reserve[MAXRESERVE];
527
528 for (;;) {
529 int io_start, io_num;
530 int x = reserved;
531
532 if (get_option (&str, &io_start) != 2)
533 break;
534 if (get_option (&str, &io_num) == 0)
535 break;
536 if (x < MAXRESERVE) {
537 struct resource *res = reserve + x;
538 res->name = "reserved";
539 res->start = io_start;
540 res->end = io_start + io_num - 1;
541 res->flags = IORESOURCE_BUSY;
542 res->child = NULL;
543 if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
544 reserved = x+1;
545 }
546 }
547 return 1;
548 }
549
550 __setup("reserve=", reserve_setup);
551
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