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7bd1d409 AS |
1 | /* |
2 | * System Trace Module (STM) infrastructure | |
3 | * Copyright (c) 2014, Intel Corporation. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms and conditions of the GNU General Public License, | |
7 | * version 2, as published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | * more details. | |
13 | * | |
14 | * STM class implements generic infrastructure for System Trace Module devices | |
15 | * as defined in MIPI STPv2 specification. | |
16 | */ | |
17 | ||
18 | #include <linux/uaccess.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/device.h> | |
22 | #include <linux/compat.h> | |
23 | #include <linux/kdev_t.h> | |
24 | #include <linux/srcu.h> | |
25 | #include <linux/slab.h> | |
26 | #include <linux/stm.h> | |
27 | #include <linux/fs.h> | |
28 | #include <linux/mm.h> | |
29 | #include "stm.h" | |
30 | ||
31 | #include <uapi/linux/stm.h> | |
32 | ||
33 | static unsigned int stm_core_up; | |
34 | ||
35 | /* | |
36 | * The SRCU here makes sure that STM device doesn't disappear from under a | |
37 | * stm_source_write() caller, which may want to have as little overhead as | |
38 | * possible. | |
39 | */ | |
40 | static struct srcu_struct stm_source_srcu; | |
41 | ||
42 | static ssize_t masters_show(struct device *dev, | |
43 | struct device_attribute *attr, | |
44 | char *buf) | |
45 | { | |
46 | struct stm_device *stm = to_stm_device(dev); | |
47 | int ret; | |
48 | ||
49 | ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end); | |
50 | ||
51 | return ret; | |
52 | } | |
53 | ||
54 | static DEVICE_ATTR_RO(masters); | |
55 | ||
56 | static ssize_t channels_show(struct device *dev, | |
57 | struct device_attribute *attr, | |
58 | char *buf) | |
59 | { | |
60 | struct stm_device *stm = to_stm_device(dev); | |
61 | int ret; | |
62 | ||
63 | ret = sprintf(buf, "%u\n", stm->data->sw_nchannels); | |
64 | ||
65 | return ret; | |
66 | } | |
67 | ||
68 | static DEVICE_ATTR_RO(channels); | |
69 | ||
70 | static struct attribute *stm_attrs[] = { | |
71 | &dev_attr_masters.attr, | |
72 | &dev_attr_channels.attr, | |
73 | NULL, | |
74 | }; | |
75 | ||
76 | ATTRIBUTE_GROUPS(stm); | |
77 | ||
78 | static struct class stm_class = { | |
79 | .name = "stm", | |
80 | .dev_groups = stm_groups, | |
81 | }; | |
82 | ||
83 | static int stm_dev_match(struct device *dev, const void *data) | |
84 | { | |
85 | const char *name = data; | |
86 | ||
87 | return sysfs_streq(name, dev_name(dev)); | |
88 | } | |
89 | ||
90 | /** | |
91 | * stm_find_device() - find stm device by name | |
92 | * @buf: character buffer containing the name | |
93 | * | |
94 | * This is called when either policy gets assigned to an stm device or an | |
95 | * stm_source device gets linked to an stm device. | |
96 | * | |
97 | * This grabs device's reference (get_device()) and module reference, both | |
98 | * of which the calling path needs to make sure to drop with stm_put_device(). | |
99 | * | |
100 | * Return: stm device pointer or null if lookup failed. | |
101 | */ | |
102 | struct stm_device *stm_find_device(const char *buf) | |
103 | { | |
104 | struct stm_device *stm; | |
105 | struct device *dev; | |
106 | ||
107 | if (!stm_core_up) | |
108 | return NULL; | |
109 | ||
110 | dev = class_find_device(&stm_class, NULL, buf, stm_dev_match); | |
111 | if (!dev) | |
112 | return NULL; | |
113 | ||
114 | stm = to_stm_device(dev); | |
115 | if (!try_module_get(stm->owner)) { | |
f7c81c71 | 116 | /* matches class_find_device() above */ |
7bd1d409 AS |
117 | put_device(dev); |
118 | return NULL; | |
119 | } | |
120 | ||
121 | return stm; | |
122 | } | |
123 | ||
124 | /** | |
125 | * stm_put_device() - drop references on the stm device | |
126 | * @stm: stm device, previously acquired by stm_find_device() | |
127 | * | |
128 | * This drops the module reference and device reference taken by | |
f7c81c71 | 129 | * stm_find_device() or stm_char_open(). |
7bd1d409 AS |
130 | */ |
131 | void stm_put_device(struct stm_device *stm) | |
132 | { | |
133 | module_put(stm->owner); | |
134 | put_device(&stm->dev); | |
135 | } | |
136 | ||
137 | /* | |
138 | * Internally we only care about software-writable masters here, that is the | |
139 | * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need | |
140 | * original master numbers to be visible externally, since they are the ones | |
141 | * that will appear in the STP stream. Thus, the internal bookkeeping uses | |
142 | * $master - stm_data->sw_start to reference master descriptors and such. | |
143 | */ | |
144 | ||
145 | #define __stm_master(_s, _m) \ | |
146 | ((_s)->masters[(_m) - (_s)->data->sw_start]) | |
147 | ||
148 | static inline struct stp_master * | |
149 | stm_master(struct stm_device *stm, unsigned int idx) | |
150 | { | |
151 | if (idx < stm->data->sw_start || idx > stm->data->sw_end) | |
152 | return NULL; | |
153 | ||
154 | return __stm_master(stm, idx); | |
155 | } | |
156 | ||
157 | static int stp_master_alloc(struct stm_device *stm, unsigned int idx) | |
158 | { | |
159 | struct stp_master *master; | |
160 | size_t size; | |
161 | ||
162 | size = ALIGN(stm->data->sw_nchannels, 8) / 8; | |
163 | size += sizeof(struct stp_master); | |
164 | master = kzalloc(size, GFP_ATOMIC); | |
165 | if (!master) | |
166 | return -ENOMEM; | |
167 | ||
168 | master->nr_free = stm->data->sw_nchannels; | |
169 | __stm_master(stm, idx) = master; | |
170 | ||
171 | return 0; | |
172 | } | |
173 | ||
174 | static void stp_master_free(struct stm_device *stm, unsigned int idx) | |
175 | { | |
176 | struct stp_master *master = stm_master(stm, idx); | |
177 | ||
178 | if (!master) | |
179 | return; | |
180 | ||
181 | __stm_master(stm, idx) = NULL; | |
182 | kfree(master); | |
183 | } | |
184 | ||
185 | static void stm_output_claim(struct stm_device *stm, struct stm_output *output) | |
186 | { | |
187 | struct stp_master *master = stm_master(stm, output->master); | |
188 | ||
cde4ad83 AS |
189 | lockdep_assert_held(&stm->mc_lock); |
190 | lockdep_assert_held(&output->lock); | |
191 | ||
7bd1d409 AS |
192 | if (WARN_ON_ONCE(master->nr_free < output->nr_chans)) |
193 | return; | |
194 | ||
195 | bitmap_allocate_region(&master->chan_map[0], output->channel, | |
196 | ilog2(output->nr_chans)); | |
197 | ||
198 | master->nr_free -= output->nr_chans; | |
199 | } | |
200 | ||
201 | static void | |
202 | stm_output_disclaim(struct stm_device *stm, struct stm_output *output) | |
203 | { | |
204 | struct stp_master *master = stm_master(stm, output->master); | |
205 | ||
cde4ad83 AS |
206 | lockdep_assert_held(&stm->mc_lock); |
207 | lockdep_assert_held(&output->lock); | |
208 | ||
7bd1d409 AS |
209 | bitmap_release_region(&master->chan_map[0], output->channel, |
210 | ilog2(output->nr_chans)); | |
211 | ||
212 | output->nr_chans = 0; | |
213 | master->nr_free += output->nr_chans; | |
214 | } | |
215 | ||
216 | /* | |
217 | * This is like bitmap_find_free_region(), except it can ignore @start bits | |
218 | * at the beginning. | |
219 | */ | |
220 | static int find_free_channels(unsigned long *bitmap, unsigned int start, | |
221 | unsigned int end, unsigned int width) | |
222 | { | |
223 | unsigned int pos; | |
224 | int i; | |
225 | ||
226 | for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) { | |
227 | pos = find_next_zero_bit(bitmap, end + 1, pos); | |
228 | if (pos + width > end + 1) | |
229 | break; | |
230 | ||
231 | if (pos & (width - 1)) | |
232 | continue; | |
233 | ||
234 | for (i = 1; i < width && !test_bit(pos + i, bitmap); i++) | |
235 | ; | |
236 | if (i == width) | |
237 | return pos; | |
238 | } | |
239 | ||
240 | return -1; | |
241 | } | |
242 | ||
f45f40ad | 243 | static int |
7bd1d409 AS |
244 | stm_find_master_chan(struct stm_device *stm, unsigned int width, |
245 | unsigned int *mstart, unsigned int mend, | |
246 | unsigned int *cstart, unsigned int cend) | |
247 | { | |
248 | struct stp_master *master; | |
249 | unsigned int midx; | |
250 | int pos, err; | |
251 | ||
252 | for (midx = *mstart; midx <= mend; midx++) { | |
253 | if (!stm_master(stm, midx)) { | |
254 | err = stp_master_alloc(stm, midx); | |
255 | if (err) | |
256 | return err; | |
257 | } | |
258 | ||
259 | master = stm_master(stm, midx); | |
260 | ||
261 | if (!master->nr_free) | |
262 | continue; | |
263 | ||
264 | pos = find_free_channels(master->chan_map, *cstart, cend, | |
265 | width); | |
266 | if (pos < 0) | |
267 | continue; | |
268 | ||
269 | *mstart = midx; | |
270 | *cstart = pos; | |
271 | return 0; | |
272 | } | |
273 | ||
274 | return -ENOSPC; | |
275 | } | |
276 | ||
277 | static int stm_output_assign(struct stm_device *stm, unsigned int width, | |
278 | struct stp_policy_node *policy_node, | |
279 | struct stm_output *output) | |
280 | { | |
281 | unsigned int midx, cidx, mend, cend; | |
282 | int ret = -EINVAL; | |
283 | ||
284 | if (width > stm->data->sw_nchannels) | |
285 | return -EINVAL; | |
286 | ||
287 | if (policy_node) { | |
288 | stp_policy_node_get_ranges(policy_node, | |
289 | &midx, &mend, &cidx, &cend); | |
290 | } else { | |
291 | midx = stm->data->sw_start; | |
292 | cidx = 0; | |
293 | mend = stm->data->sw_end; | |
294 | cend = stm->data->sw_nchannels - 1; | |
295 | } | |
296 | ||
297 | spin_lock(&stm->mc_lock); | |
cde4ad83 | 298 | spin_lock(&output->lock); |
7bd1d409 AS |
299 | /* output is already assigned -- shouldn't happen */ |
300 | if (WARN_ON_ONCE(output->nr_chans)) | |
301 | goto unlock; | |
302 | ||
303 | ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend); | |
f45f40ad | 304 | if (ret < 0) |
7bd1d409 AS |
305 | goto unlock; |
306 | ||
307 | output->master = midx; | |
308 | output->channel = cidx; | |
309 | output->nr_chans = width; | |
310 | stm_output_claim(stm, output); | |
311 | dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width); | |
312 | ||
313 | ret = 0; | |
314 | unlock: | |
cde4ad83 | 315 | spin_unlock(&output->lock); |
7bd1d409 AS |
316 | spin_unlock(&stm->mc_lock); |
317 | ||
318 | return ret; | |
319 | } | |
320 | ||
321 | static void stm_output_free(struct stm_device *stm, struct stm_output *output) | |
322 | { | |
323 | spin_lock(&stm->mc_lock); | |
cde4ad83 | 324 | spin_lock(&output->lock); |
7bd1d409 AS |
325 | if (output->nr_chans) |
326 | stm_output_disclaim(stm, output); | |
cde4ad83 | 327 | spin_unlock(&output->lock); |
7bd1d409 AS |
328 | spin_unlock(&stm->mc_lock); |
329 | } | |
330 | ||
cde4ad83 AS |
331 | static void stm_output_init(struct stm_output *output) |
332 | { | |
333 | spin_lock_init(&output->lock); | |
334 | } | |
335 | ||
7bd1d409 AS |
336 | static int major_match(struct device *dev, const void *data) |
337 | { | |
338 | unsigned int major = *(unsigned int *)data; | |
339 | ||
340 | return MAJOR(dev->devt) == major; | |
341 | } | |
342 | ||
343 | static int stm_char_open(struct inode *inode, struct file *file) | |
344 | { | |
345 | struct stm_file *stmf; | |
346 | struct device *dev; | |
347 | unsigned int major = imajor(inode); | |
348 | int err = -ENODEV; | |
349 | ||
350 | dev = class_find_device(&stm_class, NULL, &major, major_match); | |
351 | if (!dev) | |
352 | return -ENODEV; | |
353 | ||
354 | stmf = kzalloc(sizeof(*stmf), GFP_KERNEL); | |
355 | if (!stmf) | |
356 | return -ENOMEM; | |
357 | ||
cde4ad83 | 358 | stm_output_init(&stmf->output); |
7bd1d409 AS |
359 | stmf->stm = to_stm_device(dev); |
360 | ||
361 | if (!try_module_get(stmf->stm->owner)) | |
362 | goto err_free; | |
363 | ||
364 | file->private_data = stmf; | |
365 | ||
366 | return nonseekable_open(inode, file); | |
367 | ||
368 | err_free: | |
f7c81c71 AS |
369 | /* matches class_find_device() above */ |
370 | put_device(dev); | |
7bd1d409 AS |
371 | kfree(stmf); |
372 | ||
373 | return err; | |
374 | } | |
375 | ||
376 | static int stm_char_release(struct inode *inode, struct file *file) | |
377 | { | |
378 | struct stm_file *stmf = file->private_data; | |
379 | ||
380 | stm_output_free(stmf->stm, &stmf->output); | |
f7c81c71 AS |
381 | |
382 | /* | |
383 | * matches the stm_char_open()'s | |
384 | * class_find_device() + try_module_get() | |
385 | */ | |
7bd1d409 AS |
386 | stm_put_device(stmf->stm); |
387 | kfree(stmf); | |
388 | ||
389 | return 0; | |
390 | } | |
391 | ||
392 | static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) | |
393 | { | |
394 | struct stm_device *stm = stmf->stm; | |
395 | int ret; | |
396 | ||
397 | stmf->policy_node = stp_policy_node_lookup(stm, id); | |
398 | ||
399 | ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output); | |
400 | ||
401 | if (stmf->policy_node) | |
402 | stp_policy_node_put(stmf->policy_node); | |
403 | ||
404 | return ret; | |
405 | } | |
406 | ||
f8560a9b AS |
407 | static ssize_t stm_write(struct stm_data *data, unsigned int master, |
408 | unsigned int channel, const char *buf, size_t count) | |
7bd1d409 AS |
409 | { |
410 | unsigned int flags = STP_PACKET_TIMESTAMPED; | |
411 | const unsigned char *p = buf, nil = 0; | |
412 | size_t pos; | |
413 | ssize_t sz; | |
414 | ||
415 | for (pos = 0, p = buf; count > pos; pos += sz, p += sz) { | |
416 | sz = min_t(unsigned int, count - pos, 8); | |
417 | sz = data->packet(data, master, channel, STP_PACKET_DATA, flags, | |
418 | sz, p); | |
419 | flags = 0; | |
f8560a9b AS |
420 | |
421 | if (sz < 0) | |
422 | break; | |
7bd1d409 AS |
423 | } |
424 | ||
425 | data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil); | |
f8560a9b AS |
426 | |
427 | return pos; | |
7bd1d409 AS |
428 | } |
429 | ||
430 | static ssize_t stm_char_write(struct file *file, const char __user *buf, | |
431 | size_t count, loff_t *ppos) | |
432 | { | |
433 | struct stm_file *stmf = file->private_data; | |
434 | struct stm_device *stm = stmf->stm; | |
435 | char *kbuf; | |
436 | int err; | |
437 | ||
f08b1826 AS |
438 | if (count + 1 > PAGE_SIZE) |
439 | count = PAGE_SIZE - 1; | |
440 | ||
7bd1d409 AS |
441 | /* |
442 | * if no m/c have been assigned to this writer up to this | |
443 | * point, use "default" policy entry | |
444 | */ | |
445 | if (!stmf->output.nr_chans) { | |
446 | err = stm_file_assign(stmf, "default", 1); | |
447 | /* | |
448 | * EBUSY means that somebody else just assigned this | |
449 | * output, which is just fine for write() | |
450 | */ | |
451 | if (err && err != -EBUSY) | |
452 | return err; | |
453 | } | |
454 | ||
455 | kbuf = kmalloc(count + 1, GFP_KERNEL); | |
456 | if (!kbuf) | |
457 | return -ENOMEM; | |
458 | ||
459 | err = copy_from_user(kbuf, buf, count); | |
460 | if (err) { | |
461 | kfree(kbuf); | |
462 | return -EFAULT; | |
463 | } | |
464 | ||
f8560a9b AS |
465 | count = stm_write(stm->data, stmf->output.master, stmf->output.channel, |
466 | kbuf, count); | |
7bd1d409 AS |
467 | |
468 | kfree(kbuf); | |
469 | ||
470 | return count; | |
471 | } | |
472 | ||
473 | static int stm_char_mmap(struct file *file, struct vm_area_struct *vma) | |
474 | { | |
475 | struct stm_file *stmf = file->private_data; | |
476 | struct stm_device *stm = stmf->stm; | |
477 | unsigned long size, phys; | |
478 | ||
479 | if (!stm->data->mmio_addr) | |
480 | return -EOPNOTSUPP; | |
481 | ||
482 | if (vma->vm_pgoff) | |
483 | return -EINVAL; | |
484 | ||
485 | size = vma->vm_end - vma->vm_start; | |
486 | ||
487 | if (stmf->output.nr_chans * stm->data->sw_mmiosz != size) | |
488 | return -EINVAL; | |
489 | ||
490 | phys = stm->data->mmio_addr(stm->data, stmf->output.master, | |
491 | stmf->output.channel, | |
492 | stmf->output.nr_chans); | |
493 | ||
494 | if (!phys) | |
495 | return -EINVAL; | |
496 | ||
497 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
498 | vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; | |
499 | vm_iomap_memory(vma, phys, size); | |
500 | ||
501 | return 0; | |
502 | } | |
503 | ||
504 | static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg) | |
505 | { | |
506 | struct stm_device *stm = stmf->stm; | |
507 | struct stp_policy_id *id; | |
508 | int ret = -EINVAL; | |
509 | u32 size; | |
510 | ||
511 | if (stmf->output.nr_chans) | |
512 | return -EBUSY; | |
513 | ||
514 | if (copy_from_user(&size, arg, sizeof(size))) | |
515 | return -EFAULT; | |
516 | ||
517 | if (size >= PATH_MAX + sizeof(*id)) | |
518 | return -EINVAL; | |
519 | ||
520 | /* | |
521 | * size + 1 to make sure the .id string at the bottom is terminated, | |
522 | * which is also why memdup_user() is not useful here | |
523 | */ | |
524 | id = kzalloc(size + 1, GFP_KERNEL); | |
525 | if (!id) | |
526 | return -ENOMEM; | |
527 | ||
528 | if (copy_from_user(id, arg, size)) { | |
529 | ret = -EFAULT; | |
530 | goto err_free; | |
531 | } | |
532 | ||
533 | if (id->__reserved_0 || id->__reserved_1) | |
534 | goto err_free; | |
535 | ||
536 | if (id->width < 1 || | |
537 | id->width > PAGE_SIZE / stm->data->sw_mmiosz) | |
538 | goto err_free; | |
539 | ||
540 | ret = stm_file_assign(stmf, id->id, id->width); | |
541 | if (ret) | |
542 | goto err_free; | |
543 | ||
544 | ret = 0; | |
545 | ||
546 | if (stm->data->link) | |
547 | ret = stm->data->link(stm->data, stmf->output.master, | |
548 | stmf->output.channel); | |
549 | ||
f7c81c71 | 550 | if (ret) |
7bd1d409 | 551 | stm_output_free(stmf->stm, &stmf->output); |
7bd1d409 AS |
552 | |
553 | err_free: | |
554 | kfree(id); | |
555 | ||
556 | return ret; | |
557 | } | |
558 | ||
559 | static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg) | |
560 | { | |
561 | struct stp_policy_id id = { | |
562 | .size = sizeof(id), | |
563 | .master = stmf->output.master, | |
564 | .channel = stmf->output.channel, | |
565 | .width = stmf->output.nr_chans, | |
566 | .__reserved_0 = 0, | |
567 | .__reserved_1 = 0, | |
568 | }; | |
569 | ||
570 | return copy_to_user(arg, &id, id.size) ? -EFAULT : 0; | |
571 | } | |
572 | ||
573 | static long | |
574 | stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
575 | { | |
576 | struct stm_file *stmf = file->private_data; | |
577 | struct stm_data *stm_data = stmf->stm->data; | |
578 | int err = -ENOTTY; | |
579 | u64 options; | |
580 | ||
581 | switch (cmd) { | |
582 | case STP_POLICY_ID_SET: | |
583 | err = stm_char_policy_set_ioctl(stmf, (void __user *)arg); | |
584 | if (err) | |
585 | return err; | |
586 | ||
587 | return stm_char_policy_get_ioctl(stmf, (void __user *)arg); | |
588 | ||
589 | case STP_POLICY_ID_GET: | |
590 | return stm_char_policy_get_ioctl(stmf, (void __user *)arg); | |
591 | ||
592 | case STP_SET_OPTIONS: | |
593 | if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64))) | |
594 | return -EFAULT; | |
595 | ||
596 | if (stm_data->set_options) | |
597 | err = stm_data->set_options(stm_data, | |
598 | stmf->output.master, | |
599 | stmf->output.channel, | |
600 | stmf->output.nr_chans, | |
601 | options); | |
602 | ||
603 | break; | |
604 | default: | |
605 | break; | |
606 | } | |
607 | ||
608 | return err; | |
609 | } | |
610 | ||
611 | #ifdef CONFIG_COMPAT | |
612 | static long | |
613 | stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
614 | { | |
615 | return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); | |
616 | } | |
617 | #else | |
618 | #define stm_char_compat_ioctl NULL | |
619 | #endif | |
620 | ||
621 | static const struct file_operations stm_fops = { | |
622 | .open = stm_char_open, | |
623 | .release = stm_char_release, | |
624 | .write = stm_char_write, | |
625 | .mmap = stm_char_mmap, | |
626 | .unlocked_ioctl = stm_char_ioctl, | |
627 | .compat_ioctl = stm_char_compat_ioctl, | |
628 | .llseek = no_llseek, | |
629 | }; | |
630 | ||
631 | static void stm_device_release(struct device *dev) | |
632 | { | |
633 | struct stm_device *stm = to_stm_device(dev); | |
634 | ||
635 | kfree(stm); | |
636 | } | |
637 | ||
638 | int stm_register_device(struct device *parent, struct stm_data *stm_data, | |
639 | struct module *owner) | |
640 | { | |
641 | struct stm_device *stm; | |
642 | unsigned int nmasters; | |
643 | int err = -ENOMEM; | |
644 | ||
645 | if (!stm_core_up) | |
646 | return -EPROBE_DEFER; | |
647 | ||
648 | if (!stm_data->packet || !stm_data->sw_nchannels) | |
649 | return -EINVAL; | |
650 | ||
7b3bb0e7 | 651 | nmasters = stm_data->sw_end - stm_data->sw_start + 1; |
7bd1d409 AS |
652 | stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL); |
653 | if (!stm) | |
654 | return -ENOMEM; | |
655 | ||
656 | stm->major = register_chrdev(0, stm_data->name, &stm_fops); | |
657 | if (stm->major < 0) | |
658 | goto err_free; | |
659 | ||
660 | device_initialize(&stm->dev); | |
661 | stm->dev.devt = MKDEV(stm->major, 0); | |
662 | stm->dev.class = &stm_class; | |
663 | stm->dev.parent = parent; | |
664 | stm->dev.release = stm_device_release; | |
665 | ||
666 | err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name); | |
667 | if (err) | |
668 | goto err_device; | |
669 | ||
670 | err = device_add(&stm->dev); | |
671 | if (err) | |
672 | goto err_device; | |
673 | ||
c74f7e82 | 674 | mutex_init(&stm->link_mutex); |
7bd1d409 AS |
675 | spin_lock_init(&stm->link_lock); |
676 | INIT_LIST_HEAD(&stm->link_list); | |
677 | ||
678 | spin_lock_init(&stm->mc_lock); | |
679 | mutex_init(&stm->policy_mutex); | |
680 | stm->sw_nmasters = nmasters; | |
681 | stm->owner = owner; | |
682 | stm->data = stm_data; | |
683 | stm_data->stm = stm; | |
684 | ||
685 | return 0; | |
686 | ||
687 | err_device: | |
f7c81c71 | 688 | /* matches device_initialize() above */ |
7bd1d409 AS |
689 | put_device(&stm->dev); |
690 | err_free: | |
691 | kfree(stm); | |
692 | ||
693 | return err; | |
694 | } | |
695 | EXPORT_SYMBOL_GPL(stm_register_device); | |
696 | ||
b4ca34aa AS |
697 | static int __stm_source_link_drop(struct stm_source_device *src, |
698 | struct stm_device *stm); | |
7bd1d409 AS |
699 | |
700 | void stm_unregister_device(struct stm_data *stm_data) | |
701 | { | |
702 | struct stm_device *stm = stm_data->stm; | |
703 | struct stm_source_device *src, *iter; | |
b4ca34aa | 704 | int i, ret; |
7bd1d409 | 705 | |
c74f7e82 | 706 | mutex_lock(&stm->link_mutex); |
7bd1d409 | 707 | list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) { |
b4ca34aa AS |
708 | ret = __stm_source_link_drop(src, stm); |
709 | /* | |
710 | * src <-> stm link must not change under the same | |
711 | * stm::link_mutex, so complain loudly if it has; | |
712 | * also in this situation ret!=0 means this src is | |
713 | * not connected to this stm and it should be otherwise | |
714 | * safe to proceed with the tear-down of stm. | |
715 | */ | |
716 | WARN_ON_ONCE(ret); | |
7bd1d409 | 717 | } |
c74f7e82 | 718 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
719 | |
720 | synchronize_srcu(&stm_source_srcu); | |
721 | ||
722 | unregister_chrdev(stm->major, stm_data->name); | |
723 | ||
724 | mutex_lock(&stm->policy_mutex); | |
725 | if (stm->policy) | |
726 | stp_policy_unbind(stm->policy); | |
727 | mutex_unlock(&stm->policy_mutex); | |
728 | ||
73a3ed19 | 729 | for (i = stm->data->sw_start; i <= stm->data->sw_end; i++) |
7bd1d409 AS |
730 | stp_master_free(stm, i); |
731 | ||
732 | device_unregister(&stm->dev); | |
733 | stm_data->stm = NULL; | |
734 | } | |
735 | EXPORT_SYMBOL_GPL(stm_unregister_device); | |
736 | ||
c74f7e82 AS |
737 | /* |
738 | * stm::link_list access serialization uses a spinlock and a mutex; holding | |
739 | * either of them guarantees that the list is stable; modification requires | |
740 | * holding both of them. | |
741 | * | |
742 | * Lock ordering is as follows: | |
743 | * stm::link_mutex | |
744 | * stm::link_lock | |
745 | * src::link_lock | |
746 | */ | |
747 | ||
7bd1d409 AS |
748 | /** |
749 | * stm_source_link_add() - connect an stm_source device to an stm device | |
750 | * @src: stm_source device | |
751 | * @stm: stm device | |
752 | * | |
753 | * This function establishes a link from stm_source to an stm device so that | |
754 | * the former can send out trace data to the latter. | |
755 | * | |
756 | * Return: 0 on success, -errno otherwise. | |
757 | */ | |
758 | static int stm_source_link_add(struct stm_source_device *src, | |
759 | struct stm_device *stm) | |
760 | { | |
761 | char *id; | |
762 | int err; | |
763 | ||
c74f7e82 | 764 | mutex_lock(&stm->link_mutex); |
7bd1d409 AS |
765 | spin_lock(&stm->link_lock); |
766 | spin_lock(&src->link_lock); | |
767 | ||
768 | /* src->link is dereferenced under stm_source_srcu but not the list */ | |
769 | rcu_assign_pointer(src->link, stm); | |
770 | list_add_tail(&src->link_entry, &stm->link_list); | |
771 | ||
772 | spin_unlock(&src->link_lock); | |
773 | spin_unlock(&stm->link_lock); | |
c74f7e82 | 774 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
775 | |
776 | id = kstrdup(src->data->name, GFP_KERNEL); | |
777 | if (id) { | |
778 | src->policy_node = | |
779 | stp_policy_node_lookup(stm, id); | |
780 | ||
781 | kfree(id); | |
782 | } | |
783 | ||
784 | err = stm_output_assign(stm, src->data->nr_chans, | |
785 | src->policy_node, &src->output); | |
786 | ||
787 | if (src->policy_node) | |
788 | stp_policy_node_put(src->policy_node); | |
789 | ||
790 | if (err) | |
791 | goto fail_detach; | |
792 | ||
793 | /* this is to notify the STM device that a new link has been made */ | |
794 | if (stm->data->link) | |
795 | err = stm->data->link(stm->data, src->output.master, | |
796 | src->output.channel); | |
797 | ||
798 | if (err) | |
799 | goto fail_free_output; | |
800 | ||
801 | /* this is to let the source carry out all necessary preparations */ | |
802 | if (src->data->link) | |
803 | src->data->link(src->data); | |
804 | ||
805 | return 0; | |
806 | ||
807 | fail_free_output: | |
808 | stm_output_free(stm, &src->output); | |
7bd1d409 AS |
809 | |
810 | fail_detach: | |
c74f7e82 | 811 | mutex_lock(&stm->link_mutex); |
7bd1d409 AS |
812 | spin_lock(&stm->link_lock); |
813 | spin_lock(&src->link_lock); | |
814 | ||
815 | rcu_assign_pointer(src->link, NULL); | |
816 | list_del_init(&src->link_entry); | |
817 | ||
818 | spin_unlock(&src->link_lock); | |
819 | spin_unlock(&stm->link_lock); | |
c74f7e82 | 820 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
821 | |
822 | return err; | |
823 | } | |
824 | ||
825 | /** | |
826 | * __stm_source_link_drop() - detach stm_source from an stm device | |
827 | * @src: stm_source device | |
828 | * @stm: stm device | |
829 | * | |
830 | * If @stm is @src::link, disconnect them from one another and put the | |
831 | * reference on the @stm device. | |
832 | * | |
c74f7e82 | 833 | * Caller must hold stm::link_mutex. |
7bd1d409 | 834 | */ |
b4ca34aa AS |
835 | static int __stm_source_link_drop(struct stm_source_device *src, |
836 | struct stm_device *stm) | |
7bd1d409 | 837 | { |
0df771de | 838 | struct stm_device *link; |
b4ca34aa | 839 | int ret = 0; |
0df771de | 840 | |
c74f7e82 AS |
841 | lockdep_assert_held(&stm->link_mutex); |
842 | ||
c74f7e82 AS |
843 | /* for stm::link_list modification, we hold both mutex and spinlock */ |
844 | spin_lock(&stm->link_lock); | |
7bd1d409 | 845 | spin_lock(&src->link_lock); |
0df771de | 846 | link = srcu_dereference_check(src->link, &stm_source_srcu, 1); |
b4ca34aa AS |
847 | |
848 | /* | |
849 | * The linked device may have changed since we last looked, because | |
850 | * we weren't holding the src::link_lock back then; if this is the | |
851 | * case, tell the caller to retry. | |
852 | */ | |
853 | if (link != stm) { | |
854 | ret = -EAGAIN; | |
1810f2c4 | 855 | goto unlock; |
b4ca34aa | 856 | } |
7bd1d409 | 857 | |
0df771de | 858 | stm_output_free(link, &src->output); |
7bd1d409 AS |
859 | list_del_init(&src->link_entry); |
860 | /* matches stm_find_device() from stm_source_link_store() */ | |
0df771de | 861 | stm_put_device(link); |
7bd1d409 AS |
862 | rcu_assign_pointer(src->link, NULL); |
863 | ||
1810f2c4 | 864 | unlock: |
7bd1d409 | 865 | spin_unlock(&src->link_lock); |
c74f7e82 | 866 | spin_unlock(&stm->link_lock); |
b4ca34aa AS |
867 | |
868 | if (!ret && src->data->unlink) | |
869 | src->data->unlink(src->data); | |
870 | ||
871 | return ret; | |
7bd1d409 AS |
872 | } |
873 | ||
874 | /** | |
875 | * stm_source_link_drop() - detach stm_source from its stm device | |
876 | * @src: stm_source device | |
877 | * | |
878 | * Unlinking means disconnecting from source's STM device; after this | |
879 | * writes will be unsuccessful until it is linked to a new STM device. | |
880 | * | |
881 | * This will happen on "stm_source_link" sysfs attribute write to undo | |
882 | * the existing link (if any), or on linked STM device's de-registration. | |
883 | */ | |
884 | static void stm_source_link_drop(struct stm_source_device *src) | |
885 | { | |
886 | struct stm_device *stm; | |
b4ca34aa | 887 | int idx, ret; |
7bd1d409 | 888 | |
b4ca34aa | 889 | retry: |
7bd1d409 | 890 | idx = srcu_read_lock(&stm_source_srcu); |
b4ca34aa AS |
891 | /* |
892 | * The stm device will be valid for the duration of this | |
893 | * read section, but the link may change before we grab | |
894 | * the src::link_lock in __stm_source_link_drop(). | |
895 | */ | |
7bd1d409 AS |
896 | stm = srcu_dereference(src->link, &stm_source_srcu); |
897 | ||
b4ca34aa | 898 | ret = 0; |
7bd1d409 | 899 | if (stm) { |
c74f7e82 | 900 | mutex_lock(&stm->link_mutex); |
b4ca34aa | 901 | ret = __stm_source_link_drop(src, stm); |
c74f7e82 | 902 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
903 | } |
904 | ||
905 | srcu_read_unlock(&stm_source_srcu, idx); | |
b4ca34aa AS |
906 | |
907 | /* if it did change, retry */ | |
908 | if (ret == -EAGAIN) | |
909 | goto retry; | |
7bd1d409 AS |
910 | } |
911 | ||
912 | static ssize_t stm_source_link_show(struct device *dev, | |
913 | struct device_attribute *attr, | |
914 | char *buf) | |
915 | { | |
916 | struct stm_source_device *src = to_stm_source_device(dev); | |
917 | struct stm_device *stm; | |
918 | int idx, ret; | |
919 | ||
920 | idx = srcu_read_lock(&stm_source_srcu); | |
921 | stm = srcu_dereference(src->link, &stm_source_srcu); | |
922 | ret = sprintf(buf, "%s\n", | |
923 | stm ? dev_name(&stm->dev) : "<none>"); | |
924 | srcu_read_unlock(&stm_source_srcu, idx); | |
925 | ||
926 | return ret; | |
927 | } | |
928 | ||
929 | static ssize_t stm_source_link_store(struct device *dev, | |
930 | struct device_attribute *attr, | |
931 | const char *buf, size_t count) | |
932 | { | |
933 | struct stm_source_device *src = to_stm_source_device(dev); | |
934 | struct stm_device *link; | |
935 | int err; | |
936 | ||
937 | stm_source_link_drop(src); | |
938 | ||
939 | link = stm_find_device(buf); | |
940 | if (!link) | |
941 | return -EINVAL; | |
942 | ||
943 | err = stm_source_link_add(src, link); | |
f7c81c71 AS |
944 | if (err) { |
945 | /* matches the stm_find_device() above */ | |
7bd1d409 | 946 | stm_put_device(link); |
f7c81c71 | 947 | } |
7bd1d409 AS |
948 | |
949 | return err ? : count; | |
950 | } | |
951 | ||
952 | static DEVICE_ATTR_RW(stm_source_link); | |
953 | ||
954 | static struct attribute *stm_source_attrs[] = { | |
955 | &dev_attr_stm_source_link.attr, | |
956 | NULL, | |
957 | }; | |
958 | ||
959 | ATTRIBUTE_GROUPS(stm_source); | |
960 | ||
961 | static struct class stm_source_class = { | |
962 | .name = "stm_source", | |
963 | .dev_groups = stm_source_groups, | |
964 | }; | |
965 | ||
966 | static void stm_source_device_release(struct device *dev) | |
967 | { | |
968 | struct stm_source_device *src = to_stm_source_device(dev); | |
969 | ||
970 | kfree(src); | |
971 | } | |
972 | ||
973 | /** | |
974 | * stm_source_register_device() - register an stm_source device | |
975 | * @parent: parent device | |
976 | * @data: device description structure | |
977 | * | |
978 | * This will create a device of stm_source class that can write | |
979 | * data to an stm device once linked. | |
980 | * | |
981 | * Return: 0 on success, -errno otherwise. | |
982 | */ | |
983 | int stm_source_register_device(struct device *parent, | |
984 | struct stm_source_data *data) | |
985 | { | |
986 | struct stm_source_device *src; | |
987 | int err; | |
988 | ||
989 | if (!stm_core_up) | |
990 | return -EPROBE_DEFER; | |
991 | ||
992 | src = kzalloc(sizeof(*src), GFP_KERNEL); | |
993 | if (!src) | |
994 | return -ENOMEM; | |
995 | ||
996 | device_initialize(&src->dev); | |
997 | src->dev.class = &stm_source_class; | |
998 | src->dev.parent = parent; | |
999 | src->dev.release = stm_source_device_release; | |
1000 | ||
1001 | err = kobject_set_name(&src->dev.kobj, "%s", data->name); | |
1002 | if (err) | |
1003 | goto err; | |
1004 | ||
1005 | err = device_add(&src->dev); | |
1006 | if (err) | |
1007 | goto err; | |
1008 | ||
cde4ad83 | 1009 | stm_output_init(&src->output); |
7bd1d409 AS |
1010 | spin_lock_init(&src->link_lock); |
1011 | INIT_LIST_HEAD(&src->link_entry); | |
1012 | src->data = data; | |
1013 | data->src = src; | |
1014 | ||
1015 | return 0; | |
1016 | ||
1017 | err: | |
1018 | put_device(&src->dev); | |
1019 | kfree(src); | |
1020 | ||
1021 | return err; | |
1022 | } | |
1023 | EXPORT_SYMBOL_GPL(stm_source_register_device); | |
1024 | ||
1025 | /** | |
1026 | * stm_source_unregister_device() - unregister an stm_source device | |
1027 | * @data: device description that was used to register the device | |
1028 | * | |
1029 | * This will remove a previously created stm_source device from the system. | |
1030 | */ | |
1031 | void stm_source_unregister_device(struct stm_source_data *data) | |
1032 | { | |
1033 | struct stm_source_device *src = data->src; | |
1034 | ||
1035 | stm_source_link_drop(src); | |
1036 | ||
1037 | device_destroy(&stm_source_class, src->dev.devt); | |
1038 | } | |
1039 | EXPORT_SYMBOL_GPL(stm_source_unregister_device); | |
1040 | ||
1041 | int stm_source_write(struct stm_source_data *data, unsigned int chan, | |
1042 | const char *buf, size_t count) | |
1043 | { | |
1044 | struct stm_source_device *src = data->src; | |
1045 | struct stm_device *stm; | |
1046 | int idx; | |
1047 | ||
1048 | if (!src->output.nr_chans) | |
1049 | return -ENODEV; | |
1050 | ||
1051 | if (chan >= src->output.nr_chans) | |
1052 | return -EINVAL; | |
1053 | ||
1054 | idx = srcu_read_lock(&stm_source_srcu); | |
1055 | ||
1056 | stm = srcu_dereference(src->link, &stm_source_srcu); | |
1057 | if (stm) | |
f8560a9b AS |
1058 | count = stm_write(stm->data, src->output.master, |
1059 | src->output.channel + chan, | |
1060 | buf, count); | |
7bd1d409 AS |
1061 | else |
1062 | count = -ENODEV; | |
1063 | ||
1064 | srcu_read_unlock(&stm_source_srcu, idx); | |
1065 | ||
1066 | return count; | |
1067 | } | |
1068 | EXPORT_SYMBOL_GPL(stm_source_write); | |
1069 | ||
1070 | static int __init stm_core_init(void) | |
1071 | { | |
1072 | int err; | |
1073 | ||
1074 | err = class_register(&stm_class); | |
1075 | if (err) | |
1076 | return err; | |
1077 | ||
1078 | err = class_register(&stm_source_class); | |
1079 | if (err) | |
1080 | goto err_stm; | |
1081 | ||
1082 | err = stp_configfs_init(); | |
1083 | if (err) | |
1084 | goto err_src; | |
1085 | ||
1086 | init_srcu_struct(&stm_source_srcu); | |
1087 | ||
1088 | stm_core_up++; | |
1089 | ||
1090 | return 0; | |
1091 | ||
1092 | err_src: | |
1093 | class_unregister(&stm_source_class); | |
1094 | err_stm: | |
1095 | class_unregister(&stm_class); | |
1096 | ||
1097 | return err; | |
1098 | } | |
1099 | ||
1100 | module_init(stm_core_init); | |
1101 | ||
1102 | static void __exit stm_core_exit(void) | |
1103 | { | |
1104 | cleanup_srcu_struct(&stm_source_srcu); | |
1105 | class_unregister(&stm_source_class); | |
1106 | class_unregister(&stm_class); | |
1107 | stp_configfs_exit(); | |
1108 | } | |
1109 | ||
1110 | module_exit(stm_core_exit); | |
1111 | ||
1112 | MODULE_LICENSE("GPL v2"); | |
1113 | MODULE_DESCRIPTION("System Trace Module device class"); | |
1114 | MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>"); |