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Commit | Line | Data |
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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 | ||
8e996a28 AS |
70 | static ssize_t hw_override_show(struct device *dev, |
71 | struct device_attribute *attr, | |
72 | char *buf) | |
73 | { | |
74 | struct stm_device *stm = to_stm_device(dev); | |
75 | int ret; | |
76 | ||
77 | ret = sprintf(buf, "%u\n", stm->data->hw_override); | |
78 | ||
79 | return ret; | |
80 | } | |
81 | ||
82 | static DEVICE_ATTR_RO(hw_override); | |
83 | ||
7bd1d409 AS |
84 | static struct attribute *stm_attrs[] = { |
85 | &dev_attr_masters.attr, | |
86 | &dev_attr_channels.attr, | |
8e996a28 | 87 | &dev_attr_hw_override.attr, |
7bd1d409 AS |
88 | NULL, |
89 | }; | |
90 | ||
91 | ATTRIBUTE_GROUPS(stm); | |
92 | ||
93 | static struct class stm_class = { | |
94 | .name = "stm", | |
95 | .dev_groups = stm_groups, | |
96 | }; | |
97 | ||
98 | static int stm_dev_match(struct device *dev, const void *data) | |
99 | { | |
100 | const char *name = data; | |
101 | ||
102 | return sysfs_streq(name, dev_name(dev)); | |
103 | } | |
104 | ||
105 | /** | |
106 | * stm_find_device() - find stm device by name | |
107 | * @buf: character buffer containing the name | |
108 | * | |
109 | * This is called when either policy gets assigned to an stm device or an | |
110 | * stm_source device gets linked to an stm device. | |
111 | * | |
112 | * This grabs device's reference (get_device()) and module reference, both | |
113 | * of which the calling path needs to make sure to drop with stm_put_device(). | |
114 | * | |
115 | * Return: stm device pointer or null if lookup failed. | |
116 | */ | |
117 | struct stm_device *stm_find_device(const char *buf) | |
118 | { | |
119 | struct stm_device *stm; | |
120 | struct device *dev; | |
121 | ||
122 | if (!stm_core_up) | |
123 | return NULL; | |
124 | ||
125 | dev = class_find_device(&stm_class, NULL, buf, stm_dev_match); | |
126 | if (!dev) | |
127 | return NULL; | |
128 | ||
129 | stm = to_stm_device(dev); | |
130 | if (!try_module_get(stm->owner)) { | |
f7c81c71 | 131 | /* matches class_find_device() above */ |
7bd1d409 AS |
132 | put_device(dev); |
133 | return NULL; | |
134 | } | |
135 | ||
136 | return stm; | |
137 | } | |
138 | ||
139 | /** | |
140 | * stm_put_device() - drop references on the stm device | |
141 | * @stm: stm device, previously acquired by stm_find_device() | |
142 | * | |
143 | * This drops the module reference and device reference taken by | |
f7c81c71 | 144 | * stm_find_device() or stm_char_open(). |
7bd1d409 AS |
145 | */ |
146 | void stm_put_device(struct stm_device *stm) | |
147 | { | |
148 | module_put(stm->owner); | |
149 | put_device(&stm->dev); | |
150 | } | |
151 | ||
152 | /* | |
153 | * Internally we only care about software-writable masters here, that is the | |
154 | * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need | |
155 | * original master numbers to be visible externally, since they are the ones | |
156 | * that will appear in the STP stream. Thus, the internal bookkeeping uses | |
157 | * $master - stm_data->sw_start to reference master descriptors and such. | |
158 | */ | |
159 | ||
160 | #define __stm_master(_s, _m) \ | |
161 | ((_s)->masters[(_m) - (_s)->data->sw_start]) | |
162 | ||
163 | static inline struct stp_master * | |
164 | stm_master(struct stm_device *stm, unsigned int idx) | |
165 | { | |
166 | if (idx < stm->data->sw_start || idx > stm->data->sw_end) | |
167 | return NULL; | |
168 | ||
169 | return __stm_master(stm, idx); | |
170 | } | |
171 | ||
172 | static int stp_master_alloc(struct stm_device *stm, unsigned int idx) | |
173 | { | |
174 | struct stp_master *master; | |
175 | size_t size; | |
176 | ||
177 | size = ALIGN(stm->data->sw_nchannels, 8) / 8; | |
178 | size += sizeof(struct stp_master); | |
179 | master = kzalloc(size, GFP_ATOMIC); | |
180 | if (!master) | |
181 | return -ENOMEM; | |
182 | ||
183 | master->nr_free = stm->data->sw_nchannels; | |
184 | __stm_master(stm, idx) = master; | |
185 | ||
186 | return 0; | |
187 | } | |
188 | ||
189 | static void stp_master_free(struct stm_device *stm, unsigned int idx) | |
190 | { | |
191 | struct stp_master *master = stm_master(stm, idx); | |
192 | ||
193 | if (!master) | |
194 | return; | |
195 | ||
196 | __stm_master(stm, idx) = NULL; | |
197 | kfree(master); | |
198 | } | |
199 | ||
200 | static void stm_output_claim(struct stm_device *stm, struct stm_output *output) | |
201 | { | |
202 | struct stp_master *master = stm_master(stm, output->master); | |
203 | ||
cde4ad83 AS |
204 | lockdep_assert_held(&stm->mc_lock); |
205 | lockdep_assert_held(&output->lock); | |
206 | ||
7bd1d409 AS |
207 | if (WARN_ON_ONCE(master->nr_free < output->nr_chans)) |
208 | return; | |
209 | ||
210 | bitmap_allocate_region(&master->chan_map[0], output->channel, | |
211 | ilog2(output->nr_chans)); | |
212 | ||
213 | master->nr_free -= output->nr_chans; | |
214 | } | |
215 | ||
216 | static void | |
217 | stm_output_disclaim(struct stm_device *stm, struct stm_output *output) | |
218 | { | |
219 | struct stp_master *master = stm_master(stm, output->master); | |
220 | ||
cde4ad83 AS |
221 | lockdep_assert_held(&stm->mc_lock); |
222 | lockdep_assert_held(&output->lock); | |
223 | ||
7bd1d409 AS |
224 | bitmap_release_region(&master->chan_map[0], output->channel, |
225 | ilog2(output->nr_chans)); | |
226 | ||
227 | output->nr_chans = 0; | |
228 | master->nr_free += output->nr_chans; | |
229 | } | |
230 | ||
231 | /* | |
232 | * This is like bitmap_find_free_region(), except it can ignore @start bits | |
233 | * at the beginning. | |
234 | */ | |
235 | static int find_free_channels(unsigned long *bitmap, unsigned int start, | |
236 | unsigned int end, unsigned int width) | |
237 | { | |
238 | unsigned int pos; | |
239 | int i; | |
240 | ||
241 | for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) { | |
242 | pos = find_next_zero_bit(bitmap, end + 1, pos); | |
243 | if (pos + width > end + 1) | |
244 | break; | |
245 | ||
246 | if (pos & (width - 1)) | |
247 | continue; | |
248 | ||
249 | for (i = 1; i < width && !test_bit(pos + i, bitmap); i++) | |
250 | ; | |
251 | if (i == width) | |
252 | return pos; | |
253 | } | |
254 | ||
255 | return -1; | |
256 | } | |
257 | ||
f45f40ad | 258 | static int |
7bd1d409 AS |
259 | stm_find_master_chan(struct stm_device *stm, unsigned int width, |
260 | unsigned int *mstart, unsigned int mend, | |
261 | unsigned int *cstart, unsigned int cend) | |
262 | { | |
263 | struct stp_master *master; | |
264 | unsigned int midx; | |
265 | int pos, err; | |
266 | ||
267 | for (midx = *mstart; midx <= mend; midx++) { | |
268 | if (!stm_master(stm, midx)) { | |
269 | err = stp_master_alloc(stm, midx); | |
270 | if (err) | |
271 | return err; | |
272 | } | |
273 | ||
274 | master = stm_master(stm, midx); | |
275 | ||
276 | if (!master->nr_free) | |
277 | continue; | |
278 | ||
279 | pos = find_free_channels(master->chan_map, *cstart, cend, | |
280 | width); | |
281 | if (pos < 0) | |
282 | continue; | |
283 | ||
284 | *mstart = midx; | |
285 | *cstart = pos; | |
286 | return 0; | |
287 | } | |
288 | ||
289 | return -ENOSPC; | |
290 | } | |
291 | ||
292 | static int stm_output_assign(struct stm_device *stm, unsigned int width, | |
293 | struct stp_policy_node *policy_node, | |
294 | struct stm_output *output) | |
295 | { | |
296 | unsigned int midx, cidx, mend, cend; | |
297 | int ret = -EINVAL; | |
298 | ||
299 | if (width > stm->data->sw_nchannels) | |
300 | return -EINVAL; | |
301 | ||
302 | if (policy_node) { | |
303 | stp_policy_node_get_ranges(policy_node, | |
304 | &midx, &mend, &cidx, &cend); | |
305 | } else { | |
306 | midx = stm->data->sw_start; | |
307 | cidx = 0; | |
308 | mend = stm->data->sw_end; | |
309 | cend = stm->data->sw_nchannels - 1; | |
310 | } | |
311 | ||
312 | spin_lock(&stm->mc_lock); | |
cde4ad83 | 313 | spin_lock(&output->lock); |
7bd1d409 AS |
314 | /* output is already assigned -- shouldn't happen */ |
315 | if (WARN_ON_ONCE(output->nr_chans)) | |
316 | goto unlock; | |
317 | ||
318 | ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend); | |
f45f40ad | 319 | if (ret < 0) |
7bd1d409 AS |
320 | goto unlock; |
321 | ||
322 | output->master = midx; | |
323 | output->channel = cidx; | |
324 | output->nr_chans = width; | |
325 | stm_output_claim(stm, output); | |
326 | dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width); | |
327 | ||
328 | ret = 0; | |
329 | unlock: | |
cde4ad83 | 330 | spin_unlock(&output->lock); |
7bd1d409 AS |
331 | spin_unlock(&stm->mc_lock); |
332 | ||
333 | return ret; | |
334 | } | |
335 | ||
336 | static void stm_output_free(struct stm_device *stm, struct stm_output *output) | |
337 | { | |
338 | spin_lock(&stm->mc_lock); | |
cde4ad83 | 339 | spin_lock(&output->lock); |
7bd1d409 AS |
340 | if (output->nr_chans) |
341 | stm_output_disclaim(stm, output); | |
cde4ad83 | 342 | spin_unlock(&output->lock); |
7bd1d409 AS |
343 | spin_unlock(&stm->mc_lock); |
344 | } | |
345 | ||
cde4ad83 AS |
346 | static void stm_output_init(struct stm_output *output) |
347 | { | |
348 | spin_lock_init(&output->lock); | |
349 | } | |
350 | ||
7bd1d409 AS |
351 | static int major_match(struct device *dev, const void *data) |
352 | { | |
353 | unsigned int major = *(unsigned int *)data; | |
354 | ||
355 | return MAJOR(dev->devt) == major; | |
356 | } | |
357 | ||
358 | static int stm_char_open(struct inode *inode, struct file *file) | |
359 | { | |
360 | struct stm_file *stmf; | |
361 | struct device *dev; | |
362 | unsigned int major = imajor(inode); | |
363 | int err = -ENODEV; | |
364 | ||
365 | dev = class_find_device(&stm_class, NULL, &major, major_match); | |
366 | if (!dev) | |
367 | return -ENODEV; | |
368 | ||
369 | stmf = kzalloc(sizeof(*stmf), GFP_KERNEL); | |
370 | if (!stmf) | |
371 | return -ENOMEM; | |
372 | ||
cde4ad83 | 373 | stm_output_init(&stmf->output); |
7bd1d409 AS |
374 | stmf->stm = to_stm_device(dev); |
375 | ||
376 | if (!try_module_get(stmf->stm->owner)) | |
377 | goto err_free; | |
378 | ||
379 | file->private_data = stmf; | |
380 | ||
381 | return nonseekable_open(inode, file); | |
382 | ||
383 | err_free: | |
f7c81c71 AS |
384 | /* matches class_find_device() above */ |
385 | put_device(dev); | |
7bd1d409 AS |
386 | kfree(stmf); |
387 | ||
388 | return err; | |
389 | } | |
390 | ||
391 | static int stm_char_release(struct inode *inode, struct file *file) | |
392 | { | |
393 | struct stm_file *stmf = file->private_data; | |
cc842407 AS |
394 | struct stm_device *stm = stmf->stm; |
395 | ||
396 | if (stm->data->unlink) | |
397 | stm->data->unlink(stm->data, stmf->output.master, | |
398 | stmf->output.channel); | |
7bd1d409 | 399 | |
cc842407 | 400 | stm_output_free(stm, &stmf->output); |
f7c81c71 AS |
401 | |
402 | /* | |
403 | * matches the stm_char_open()'s | |
404 | * class_find_device() + try_module_get() | |
405 | */ | |
cc842407 | 406 | stm_put_device(stm); |
7bd1d409 AS |
407 | kfree(stmf); |
408 | ||
409 | return 0; | |
410 | } | |
411 | ||
412 | static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) | |
413 | { | |
414 | struct stm_device *stm = stmf->stm; | |
415 | int ret; | |
416 | ||
417 | stmf->policy_node = stp_policy_node_lookup(stm, id); | |
418 | ||
419 | ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output); | |
420 | ||
421 | if (stmf->policy_node) | |
422 | stp_policy_node_put(stmf->policy_node); | |
423 | ||
424 | return ret; | |
425 | } | |
426 | ||
f8560a9b AS |
427 | static ssize_t stm_write(struct stm_data *data, unsigned int master, |
428 | unsigned int channel, const char *buf, size_t count) | |
7bd1d409 AS |
429 | { |
430 | unsigned int flags = STP_PACKET_TIMESTAMPED; | |
431 | const unsigned char *p = buf, nil = 0; | |
432 | size_t pos; | |
433 | ssize_t sz; | |
434 | ||
435 | for (pos = 0, p = buf; count > pos; pos += sz, p += sz) { | |
436 | sz = min_t(unsigned int, count - pos, 8); | |
437 | sz = data->packet(data, master, channel, STP_PACKET_DATA, flags, | |
438 | sz, p); | |
439 | flags = 0; | |
f8560a9b AS |
440 | |
441 | if (sz < 0) | |
442 | break; | |
7bd1d409 AS |
443 | } |
444 | ||
445 | data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil); | |
f8560a9b AS |
446 | |
447 | return pos; | |
7bd1d409 AS |
448 | } |
449 | ||
450 | static ssize_t stm_char_write(struct file *file, const char __user *buf, | |
451 | size_t count, loff_t *ppos) | |
452 | { | |
453 | struct stm_file *stmf = file->private_data; | |
454 | struct stm_device *stm = stmf->stm; | |
455 | char *kbuf; | |
456 | int err; | |
457 | ||
f08b1826 AS |
458 | if (count + 1 > PAGE_SIZE) |
459 | count = PAGE_SIZE - 1; | |
460 | ||
7bd1d409 AS |
461 | /* |
462 | * if no m/c have been assigned to this writer up to this | |
463 | * point, use "default" policy entry | |
464 | */ | |
465 | if (!stmf->output.nr_chans) { | |
466 | err = stm_file_assign(stmf, "default", 1); | |
467 | /* | |
468 | * EBUSY means that somebody else just assigned this | |
469 | * output, which is just fine for write() | |
470 | */ | |
471 | if (err && err != -EBUSY) | |
472 | return err; | |
473 | } | |
474 | ||
475 | kbuf = kmalloc(count + 1, GFP_KERNEL); | |
476 | if (!kbuf) | |
477 | return -ENOMEM; | |
478 | ||
479 | err = copy_from_user(kbuf, buf, count); | |
480 | if (err) { | |
481 | kfree(kbuf); | |
482 | return -EFAULT; | |
483 | } | |
484 | ||
f8560a9b AS |
485 | count = stm_write(stm->data, stmf->output.master, stmf->output.channel, |
486 | kbuf, count); | |
7bd1d409 AS |
487 | |
488 | kfree(kbuf); | |
489 | ||
490 | return count; | |
491 | } | |
492 | ||
493 | static int stm_char_mmap(struct file *file, struct vm_area_struct *vma) | |
494 | { | |
495 | struct stm_file *stmf = file->private_data; | |
496 | struct stm_device *stm = stmf->stm; | |
497 | unsigned long size, phys; | |
498 | ||
499 | if (!stm->data->mmio_addr) | |
500 | return -EOPNOTSUPP; | |
501 | ||
502 | if (vma->vm_pgoff) | |
503 | return -EINVAL; | |
504 | ||
505 | size = vma->vm_end - vma->vm_start; | |
506 | ||
507 | if (stmf->output.nr_chans * stm->data->sw_mmiosz != size) | |
508 | return -EINVAL; | |
509 | ||
510 | phys = stm->data->mmio_addr(stm->data, stmf->output.master, | |
511 | stmf->output.channel, | |
512 | stmf->output.nr_chans); | |
513 | ||
514 | if (!phys) | |
515 | return -EINVAL; | |
516 | ||
517 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); | |
518 | vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; | |
519 | vm_iomap_memory(vma, phys, size); | |
520 | ||
521 | return 0; | |
522 | } | |
523 | ||
524 | static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg) | |
525 | { | |
526 | struct stm_device *stm = stmf->stm; | |
527 | struct stp_policy_id *id; | |
528 | int ret = -EINVAL; | |
529 | u32 size; | |
530 | ||
531 | if (stmf->output.nr_chans) | |
532 | return -EBUSY; | |
533 | ||
534 | if (copy_from_user(&size, arg, sizeof(size))) | |
535 | return -EFAULT; | |
536 | ||
537 | if (size >= PATH_MAX + sizeof(*id)) | |
538 | return -EINVAL; | |
539 | ||
540 | /* | |
541 | * size + 1 to make sure the .id string at the bottom is terminated, | |
542 | * which is also why memdup_user() is not useful here | |
543 | */ | |
544 | id = kzalloc(size + 1, GFP_KERNEL); | |
545 | if (!id) | |
546 | return -ENOMEM; | |
547 | ||
548 | if (copy_from_user(id, arg, size)) { | |
549 | ret = -EFAULT; | |
550 | goto err_free; | |
551 | } | |
552 | ||
553 | if (id->__reserved_0 || id->__reserved_1) | |
554 | goto err_free; | |
555 | ||
556 | if (id->width < 1 || | |
557 | id->width > PAGE_SIZE / stm->data->sw_mmiosz) | |
558 | goto err_free; | |
559 | ||
560 | ret = stm_file_assign(stmf, id->id, id->width); | |
561 | if (ret) | |
562 | goto err_free; | |
563 | ||
7bd1d409 AS |
564 | if (stm->data->link) |
565 | ret = stm->data->link(stm->data, stmf->output.master, | |
566 | stmf->output.channel); | |
567 | ||
f7c81c71 | 568 | if (ret) |
7bd1d409 | 569 | stm_output_free(stmf->stm, &stmf->output); |
7bd1d409 AS |
570 | |
571 | err_free: | |
572 | kfree(id); | |
573 | ||
574 | return ret; | |
575 | } | |
576 | ||
577 | static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg) | |
578 | { | |
579 | struct stp_policy_id id = { | |
580 | .size = sizeof(id), | |
581 | .master = stmf->output.master, | |
582 | .channel = stmf->output.channel, | |
583 | .width = stmf->output.nr_chans, | |
584 | .__reserved_0 = 0, | |
585 | .__reserved_1 = 0, | |
586 | }; | |
587 | ||
588 | return copy_to_user(arg, &id, id.size) ? -EFAULT : 0; | |
589 | } | |
590 | ||
591 | static long | |
592 | stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
593 | { | |
594 | struct stm_file *stmf = file->private_data; | |
595 | struct stm_data *stm_data = stmf->stm->data; | |
596 | int err = -ENOTTY; | |
597 | u64 options; | |
598 | ||
599 | switch (cmd) { | |
600 | case STP_POLICY_ID_SET: | |
601 | err = stm_char_policy_set_ioctl(stmf, (void __user *)arg); | |
602 | if (err) | |
603 | return err; | |
604 | ||
605 | return stm_char_policy_get_ioctl(stmf, (void __user *)arg); | |
606 | ||
607 | case STP_POLICY_ID_GET: | |
608 | return stm_char_policy_get_ioctl(stmf, (void __user *)arg); | |
609 | ||
610 | case STP_SET_OPTIONS: | |
611 | if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64))) | |
612 | return -EFAULT; | |
613 | ||
614 | if (stm_data->set_options) | |
615 | err = stm_data->set_options(stm_data, | |
616 | stmf->output.master, | |
617 | stmf->output.channel, | |
618 | stmf->output.nr_chans, | |
619 | options); | |
620 | ||
621 | break; | |
622 | default: | |
623 | break; | |
624 | } | |
625 | ||
626 | return err; | |
627 | } | |
628 | ||
629 | #ifdef CONFIG_COMPAT | |
630 | static long | |
631 | stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
632 | { | |
633 | return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); | |
634 | } | |
635 | #else | |
636 | #define stm_char_compat_ioctl NULL | |
637 | #endif | |
638 | ||
639 | static const struct file_operations stm_fops = { | |
640 | .open = stm_char_open, | |
641 | .release = stm_char_release, | |
642 | .write = stm_char_write, | |
643 | .mmap = stm_char_mmap, | |
644 | .unlocked_ioctl = stm_char_ioctl, | |
645 | .compat_ioctl = stm_char_compat_ioctl, | |
646 | .llseek = no_llseek, | |
647 | }; | |
648 | ||
649 | static void stm_device_release(struct device *dev) | |
650 | { | |
651 | struct stm_device *stm = to_stm_device(dev); | |
652 | ||
653 | kfree(stm); | |
654 | } | |
655 | ||
656 | int stm_register_device(struct device *parent, struct stm_data *stm_data, | |
657 | struct module *owner) | |
658 | { | |
659 | struct stm_device *stm; | |
660 | unsigned int nmasters; | |
661 | int err = -ENOMEM; | |
662 | ||
663 | if (!stm_core_up) | |
664 | return -EPROBE_DEFER; | |
665 | ||
666 | if (!stm_data->packet || !stm_data->sw_nchannels) | |
667 | return -EINVAL; | |
668 | ||
7b3bb0e7 | 669 | nmasters = stm_data->sw_end - stm_data->sw_start + 1; |
7bd1d409 AS |
670 | stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL); |
671 | if (!stm) | |
672 | return -ENOMEM; | |
673 | ||
674 | stm->major = register_chrdev(0, stm_data->name, &stm_fops); | |
675 | if (stm->major < 0) | |
676 | goto err_free; | |
677 | ||
678 | device_initialize(&stm->dev); | |
679 | stm->dev.devt = MKDEV(stm->major, 0); | |
680 | stm->dev.class = &stm_class; | |
681 | stm->dev.parent = parent; | |
682 | stm->dev.release = stm_device_release; | |
683 | ||
c74f7e82 | 684 | mutex_init(&stm->link_mutex); |
7bd1d409 AS |
685 | spin_lock_init(&stm->link_lock); |
686 | INIT_LIST_HEAD(&stm->link_list); | |
687 | ||
389b6699 | 688 | /* initialize the object before it is accessible via sysfs */ |
7bd1d409 AS |
689 | spin_lock_init(&stm->mc_lock); |
690 | mutex_init(&stm->policy_mutex); | |
691 | stm->sw_nmasters = nmasters; | |
692 | stm->owner = owner; | |
693 | stm->data = stm_data; | |
694 | stm_data->stm = stm; | |
695 | ||
389b6699 AS |
696 | err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name); |
697 | if (err) | |
698 | goto err_device; | |
699 | ||
700 | err = device_add(&stm->dev); | |
701 | if (err) | |
702 | goto err_device; | |
703 | ||
7bd1d409 AS |
704 | return 0; |
705 | ||
706 | err_device: | |
cbe4a61d AS |
707 | unregister_chrdev(stm->major, stm_data->name); |
708 | ||
f7c81c71 | 709 | /* matches device_initialize() above */ |
7bd1d409 AS |
710 | put_device(&stm->dev); |
711 | err_free: | |
712 | kfree(stm); | |
713 | ||
714 | return err; | |
715 | } | |
716 | EXPORT_SYMBOL_GPL(stm_register_device); | |
717 | ||
b4ca34aa AS |
718 | static int __stm_source_link_drop(struct stm_source_device *src, |
719 | struct stm_device *stm); | |
7bd1d409 AS |
720 | |
721 | void stm_unregister_device(struct stm_data *stm_data) | |
722 | { | |
723 | struct stm_device *stm = stm_data->stm; | |
724 | struct stm_source_device *src, *iter; | |
b4ca34aa | 725 | int i, ret; |
7bd1d409 | 726 | |
c74f7e82 | 727 | mutex_lock(&stm->link_mutex); |
7bd1d409 | 728 | list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) { |
b4ca34aa AS |
729 | ret = __stm_source_link_drop(src, stm); |
730 | /* | |
731 | * src <-> stm link must not change under the same | |
732 | * stm::link_mutex, so complain loudly if it has; | |
733 | * also in this situation ret!=0 means this src is | |
734 | * not connected to this stm and it should be otherwise | |
735 | * safe to proceed with the tear-down of stm. | |
736 | */ | |
737 | WARN_ON_ONCE(ret); | |
7bd1d409 | 738 | } |
c74f7e82 | 739 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
740 | |
741 | synchronize_srcu(&stm_source_srcu); | |
742 | ||
743 | unregister_chrdev(stm->major, stm_data->name); | |
744 | ||
745 | mutex_lock(&stm->policy_mutex); | |
746 | if (stm->policy) | |
747 | stp_policy_unbind(stm->policy); | |
748 | mutex_unlock(&stm->policy_mutex); | |
749 | ||
73a3ed19 | 750 | for (i = stm->data->sw_start; i <= stm->data->sw_end; i++) |
7bd1d409 AS |
751 | stp_master_free(stm, i); |
752 | ||
753 | device_unregister(&stm->dev); | |
754 | stm_data->stm = NULL; | |
755 | } | |
756 | EXPORT_SYMBOL_GPL(stm_unregister_device); | |
757 | ||
c74f7e82 AS |
758 | /* |
759 | * stm::link_list access serialization uses a spinlock and a mutex; holding | |
760 | * either of them guarantees that the list is stable; modification requires | |
761 | * holding both of them. | |
762 | * | |
763 | * Lock ordering is as follows: | |
764 | * stm::link_mutex | |
765 | * stm::link_lock | |
766 | * src::link_lock | |
767 | */ | |
768 | ||
7bd1d409 AS |
769 | /** |
770 | * stm_source_link_add() - connect an stm_source device to an stm device | |
771 | * @src: stm_source device | |
772 | * @stm: stm device | |
773 | * | |
774 | * This function establishes a link from stm_source to an stm device so that | |
775 | * the former can send out trace data to the latter. | |
776 | * | |
777 | * Return: 0 on success, -errno otherwise. | |
778 | */ | |
779 | static int stm_source_link_add(struct stm_source_device *src, | |
780 | struct stm_device *stm) | |
781 | { | |
782 | char *id; | |
783 | int err; | |
784 | ||
c74f7e82 | 785 | mutex_lock(&stm->link_mutex); |
7bd1d409 AS |
786 | spin_lock(&stm->link_lock); |
787 | spin_lock(&src->link_lock); | |
788 | ||
789 | /* src->link is dereferenced under stm_source_srcu but not the list */ | |
790 | rcu_assign_pointer(src->link, stm); | |
791 | list_add_tail(&src->link_entry, &stm->link_list); | |
792 | ||
793 | spin_unlock(&src->link_lock); | |
794 | spin_unlock(&stm->link_lock); | |
c74f7e82 | 795 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
796 | |
797 | id = kstrdup(src->data->name, GFP_KERNEL); | |
798 | if (id) { | |
799 | src->policy_node = | |
800 | stp_policy_node_lookup(stm, id); | |
801 | ||
802 | kfree(id); | |
803 | } | |
804 | ||
805 | err = stm_output_assign(stm, src->data->nr_chans, | |
806 | src->policy_node, &src->output); | |
807 | ||
808 | if (src->policy_node) | |
809 | stp_policy_node_put(src->policy_node); | |
810 | ||
811 | if (err) | |
812 | goto fail_detach; | |
813 | ||
814 | /* this is to notify the STM device that a new link has been made */ | |
815 | if (stm->data->link) | |
816 | err = stm->data->link(stm->data, src->output.master, | |
817 | src->output.channel); | |
818 | ||
819 | if (err) | |
820 | goto fail_free_output; | |
821 | ||
822 | /* this is to let the source carry out all necessary preparations */ | |
823 | if (src->data->link) | |
824 | src->data->link(src->data); | |
825 | ||
826 | return 0; | |
827 | ||
828 | fail_free_output: | |
829 | stm_output_free(stm, &src->output); | |
7bd1d409 AS |
830 | |
831 | fail_detach: | |
c74f7e82 | 832 | mutex_lock(&stm->link_mutex); |
7bd1d409 AS |
833 | spin_lock(&stm->link_lock); |
834 | spin_lock(&src->link_lock); | |
835 | ||
836 | rcu_assign_pointer(src->link, NULL); | |
837 | list_del_init(&src->link_entry); | |
838 | ||
839 | spin_unlock(&src->link_lock); | |
840 | spin_unlock(&stm->link_lock); | |
c74f7e82 | 841 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
842 | |
843 | return err; | |
844 | } | |
845 | ||
846 | /** | |
847 | * __stm_source_link_drop() - detach stm_source from an stm device | |
848 | * @src: stm_source device | |
849 | * @stm: stm device | |
850 | * | |
851 | * If @stm is @src::link, disconnect them from one another and put the | |
852 | * reference on the @stm device. | |
853 | * | |
c74f7e82 | 854 | * Caller must hold stm::link_mutex. |
7bd1d409 | 855 | */ |
b4ca34aa AS |
856 | static int __stm_source_link_drop(struct stm_source_device *src, |
857 | struct stm_device *stm) | |
7bd1d409 | 858 | { |
0df771de | 859 | struct stm_device *link; |
b4ca34aa | 860 | int ret = 0; |
0df771de | 861 | |
c74f7e82 AS |
862 | lockdep_assert_held(&stm->link_mutex); |
863 | ||
c74f7e82 AS |
864 | /* for stm::link_list modification, we hold both mutex and spinlock */ |
865 | spin_lock(&stm->link_lock); | |
7bd1d409 | 866 | spin_lock(&src->link_lock); |
0df771de | 867 | link = srcu_dereference_check(src->link, &stm_source_srcu, 1); |
b4ca34aa AS |
868 | |
869 | /* | |
870 | * The linked device may have changed since we last looked, because | |
871 | * we weren't holding the src::link_lock back then; if this is the | |
872 | * case, tell the caller to retry. | |
873 | */ | |
874 | if (link != stm) { | |
875 | ret = -EAGAIN; | |
1810f2c4 | 876 | goto unlock; |
b4ca34aa | 877 | } |
7bd1d409 | 878 | |
0df771de | 879 | stm_output_free(link, &src->output); |
7bd1d409 AS |
880 | list_del_init(&src->link_entry); |
881 | /* matches stm_find_device() from stm_source_link_store() */ | |
0df771de | 882 | stm_put_device(link); |
7bd1d409 AS |
883 | rcu_assign_pointer(src->link, NULL); |
884 | ||
1810f2c4 | 885 | unlock: |
7bd1d409 | 886 | spin_unlock(&src->link_lock); |
c74f7e82 | 887 | spin_unlock(&stm->link_lock); |
b4ca34aa | 888 | |
cc842407 AS |
889 | /* |
890 | * Call the unlink callbacks for both source and stm, when we know | |
891 | * that we have actually performed the unlinking. | |
892 | */ | |
893 | if (!ret) { | |
894 | if (src->data->unlink) | |
895 | src->data->unlink(src->data); | |
896 | ||
897 | if (stm->data->unlink) | |
898 | stm->data->unlink(stm->data, src->output.master, | |
899 | src->output.channel); | |
900 | } | |
b4ca34aa AS |
901 | |
902 | return ret; | |
7bd1d409 AS |
903 | } |
904 | ||
905 | /** | |
906 | * stm_source_link_drop() - detach stm_source from its stm device | |
907 | * @src: stm_source device | |
908 | * | |
909 | * Unlinking means disconnecting from source's STM device; after this | |
910 | * writes will be unsuccessful until it is linked to a new STM device. | |
911 | * | |
912 | * This will happen on "stm_source_link" sysfs attribute write to undo | |
913 | * the existing link (if any), or on linked STM device's de-registration. | |
914 | */ | |
915 | static void stm_source_link_drop(struct stm_source_device *src) | |
916 | { | |
917 | struct stm_device *stm; | |
b4ca34aa | 918 | int idx, ret; |
7bd1d409 | 919 | |
b4ca34aa | 920 | retry: |
7bd1d409 | 921 | idx = srcu_read_lock(&stm_source_srcu); |
b4ca34aa AS |
922 | /* |
923 | * The stm device will be valid for the duration of this | |
924 | * read section, but the link may change before we grab | |
925 | * the src::link_lock in __stm_source_link_drop(). | |
926 | */ | |
7bd1d409 AS |
927 | stm = srcu_dereference(src->link, &stm_source_srcu); |
928 | ||
b4ca34aa | 929 | ret = 0; |
7bd1d409 | 930 | if (stm) { |
c74f7e82 | 931 | mutex_lock(&stm->link_mutex); |
b4ca34aa | 932 | ret = __stm_source_link_drop(src, stm); |
c74f7e82 | 933 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
934 | } |
935 | ||
936 | srcu_read_unlock(&stm_source_srcu, idx); | |
b4ca34aa AS |
937 | |
938 | /* if it did change, retry */ | |
939 | if (ret == -EAGAIN) | |
940 | goto retry; | |
7bd1d409 AS |
941 | } |
942 | ||
943 | static ssize_t stm_source_link_show(struct device *dev, | |
944 | struct device_attribute *attr, | |
945 | char *buf) | |
946 | { | |
947 | struct stm_source_device *src = to_stm_source_device(dev); | |
948 | struct stm_device *stm; | |
949 | int idx, ret; | |
950 | ||
951 | idx = srcu_read_lock(&stm_source_srcu); | |
952 | stm = srcu_dereference(src->link, &stm_source_srcu); | |
953 | ret = sprintf(buf, "%s\n", | |
954 | stm ? dev_name(&stm->dev) : "<none>"); | |
955 | srcu_read_unlock(&stm_source_srcu, idx); | |
956 | ||
957 | return ret; | |
958 | } | |
959 | ||
960 | static ssize_t stm_source_link_store(struct device *dev, | |
961 | struct device_attribute *attr, | |
962 | const char *buf, size_t count) | |
963 | { | |
964 | struct stm_source_device *src = to_stm_source_device(dev); | |
965 | struct stm_device *link; | |
966 | int err; | |
967 | ||
968 | stm_source_link_drop(src); | |
969 | ||
970 | link = stm_find_device(buf); | |
971 | if (!link) | |
972 | return -EINVAL; | |
973 | ||
974 | err = stm_source_link_add(src, link); | |
f7c81c71 AS |
975 | if (err) { |
976 | /* matches the stm_find_device() above */ | |
7bd1d409 | 977 | stm_put_device(link); |
f7c81c71 | 978 | } |
7bd1d409 AS |
979 | |
980 | return err ? : count; | |
981 | } | |
982 | ||
983 | static DEVICE_ATTR_RW(stm_source_link); | |
984 | ||
985 | static struct attribute *stm_source_attrs[] = { | |
986 | &dev_attr_stm_source_link.attr, | |
987 | NULL, | |
988 | }; | |
989 | ||
990 | ATTRIBUTE_GROUPS(stm_source); | |
991 | ||
992 | static struct class stm_source_class = { | |
993 | .name = "stm_source", | |
994 | .dev_groups = stm_source_groups, | |
995 | }; | |
996 | ||
997 | static void stm_source_device_release(struct device *dev) | |
998 | { | |
999 | struct stm_source_device *src = to_stm_source_device(dev); | |
1000 | ||
1001 | kfree(src); | |
1002 | } | |
1003 | ||
1004 | /** | |
1005 | * stm_source_register_device() - register an stm_source device | |
1006 | * @parent: parent device | |
1007 | * @data: device description structure | |
1008 | * | |
1009 | * This will create a device of stm_source class that can write | |
1010 | * data to an stm device once linked. | |
1011 | * | |
1012 | * Return: 0 on success, -errno otherwise. | |
1013 | */ | |
1014 | int stm_source_register_device(struct device *parent, | |
1015 | struct stm_source_data *data) | |
1016 | { | |
1017 | struct stm_source_device *src; | |
1018 | int err; | |
1019 | ||
1020 | if (!stm_core_up) | |
1021 | return -EPROBE_DEFER; | |
1022 | ||
1023 | src = kzalloc(sizeof(*src), GFP_KERNEL); | |
1024 | if (!src) | |
1025 | return -ENOMEM; | |
1026 | ||
1027 | device_initialize(&src->dev); | |
1028 | src->dev.class = &stm_source_class; | |
1029 | src->dev.parent = parent; | |
1030 | src->dev.release = stm_source_device_release; | |
1031 | ||
1032 | err = kobject_set_name(&src->dev.kobj, "%s", data->name); | |
1033 | if (err) | |
1034 | goto err; | |
1035 | ||
1036 | err = device_add(&src->dev); | |
1037 | if (err) | |
1038 | goto err; | |
1039 | ||
cde4ad83 | 1040 | stm_output_init(&src->output); |
7bd1d409 AS |
1041 | spin_lock_init(&src->link_lock); |
1042 | INIT_LIST_HEAD(&src->link_entry); | |
1043 | src->data = data; | |
1044 | data->src = src; | |
1045 | ||
1046 | return 0; | |
1047 | ||
1048 | err: | |
1049 | put_device(&src->dev); | |
1050 | kfree(src); | |
1051 | ||
1052 | return err; | |
1053 | } | |
1054 | EXPORT_SYMBOL_GPL(stm_source_register_device); | |
1055 | ||
1056 | /** | |
1057 | * stm_source_unregister_device() - unregister an stm_source device | |
1058 | * @data: device description that was used to register the device | |
1059 | * | |
1060 | * This will remove a previously created stm_source device from the system. | |
1061 | */ | |
1062 | void stm_source_unregister_device(struct stm_source_data *data) | |
1063 | { | |
1064 | struct stm_source_device *src = data->src; | |
1065 | ||
1066 | stm_source_link_drop(src); | |
1067 | ||
1068 | device_destroy(&stm_source_class, src->dev.devt); | |
1069 | } | |
1070 | EXPORT_SYMBOL_GPL(stm_source_unregister_device); | |
1071 | ||
1072 | int stm_source_write(struct stm_source_data *data, unsigned int chan, | |
1073 | const char *buf, size_t count) | |
1074 | { | |
1075 | struct stm_source_device *src = data->src; | |
1076 | struct stm_device *stm; | |
1077 | int idx; | |
1078 | ||
1079 | if (!src->output.nr_chans) | |
1080 | return -ENODEV; | |
1081 | ||
1082 | if (chan >= src->output.nr_chans) | |
1083 | return -EINVAL; | |
1084 | ||
1085 | idx = srcu_read_lock(&stm_source_srcu); | |
1086 | ||
1087 | stm = srcu_dereference(src->link, &stm_source_srcu); | |
1088 | if (stm) | |
f8560a9b AS |
1089 | count = stm_write(stm->data, src->output.master, |
1090 | src->output.channel + chan, | |
1091 | buf, count); | |
7bd1d409 AS |
1092 | else |
1093 | count = -ENODEV; | |
1094 | ||
1095 | srcu_read_unlock(&stm_source_srcu, idx); | |
1096 | ||
1097 | return count; | |
1098 | } | |
1099 | EXPORT_SYMBOL_GPL(stm_source_write); | |
1100 | ||
1101 | static int __init stm_core_init(void) | |
1102 | { | |
1103 | int err; | |
1104 | ||
1105 | err = class_register(&stm_class); | |
1106 | if (err) | |
1107 | return err; | |
1108 | ||
1109 | err = class_register(&stm_source_class); | |
1110 | if (err) | |
1111 | goto err_stm; | |
1112 | ||
1113 | err = stp_configfs_init(); | |
1114 | if (err) | |
1115 | goto err_src; | |
1116 | ||
1117 | init_srcu_struct(&stm_source_srcu); | |
1118 | ||
1119 | stm_core_up++; | |
1120 | ||
1121 | return 0; | |
1122 | ||
1123 | err_src: | |
1124 | class_unregister(&stm_source_class); | |
1125 | err_stm: | |
1126 | class_unregister(&stm_class); | |
1127 | ||
1128 | return err; | |
1129 | } | |
1130 | ||
1131 | module_init(stm_core_init); | |
1132 | ||
1133 | static void __exit stm_core_exit(void) | |
1134 | { | |
1135 | cleanup_srcu_struct(&stm_source_srcu); | |
1136 | class_unregister(&stm_source_class); | |
1137 | class_unregister(&stm_class); | |
1138 | stp_configfs_exit(); | |
1139 | } | |
1140 | ||
1141 | module_exit(stm_core_exit); | |
1142 | ||
1143 | MODULE_LICENSE("GPL v2"); | |
1144 | MODULE_DESCRIPTION("System Trace Module device class"); | |
1145 | MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>"); |