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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 | ||
8e0469a4 | 18 | #include <linux/pm_runtime.h> |
7bd1d409 AS |
19 | #include <linux/uaccess.h> |
20 | #include <linux/kernel.h> | |
21 | #include <linux/module.h> | |
22 | #include <linux/device.h> | |
23 | #include <linux/compat.h> | |
24 | #include <linux/kdev_t.h> | |
25 | #include <linux/srcu.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/stm.h> | |
28 | #include <linux/fs.h> | |
29 | #include <linux/mm.h> | |
30 | #include "stm.h" | |
31 | ||
32 | #include <uapi/linux/stm.h> | |
33 | ||
34 | static unsigned int stm_core_up; | |
35 | ||
36 | /* | |
37 | * The SRCU here makes sure that STM device doesn't disappear from under a | |
38 | * stm_source_write() caller, which may want to have as little overhead as | |
39 | * possible. | |
40 | */ | |
41 | static struct srcu_struct stm_source_srcu; | |
42 | ||
43 | static ssize_t masters_show(struct device *dev, | |
44 | struct device_attribute *attr, | |
45 | char *buf) | |
46 | { | |
47 | struct stm_device *stm = to_stm_device(dev); | |
48 | int ret; | |
49 | ||
50 | ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end); | |
51 | ||
52 | return ret; | |
53 | } | |
54 | ||
55 | static DEVICE_ATTR_RO(masters); | |
56 | ||
57 | static ssize_t channels_show(struct device *dev, | |
58 | struct device_attribute *attr, | |
59 | char *buf) | |
60 | { | |
61 | struct stm_device *stm = to_stm_device(dev); | |
62 | int ret; | |
63 | ||
64 | ret = sprintf(buf, "%u\n", stm->data->sw_nchannels); | |
65 | ||
66 | return ret; | |
67 | } | |
68 | ||
69 | static DEVICE_ATTR_RO(channels); | |
70 | ||
8e996a28 AS |
71 | static ssize_t hw_override_show(struct device *dev, |
72 | struct device_attribute *attr, | |
73 | char *buf) | |
74 | { | |
75 | struct stm_device *stm = to_stm_device(dev); | |
76 | int ret; | |
77 | ||
78 | ret = sprintf(buf, "%u\n", stm->data->hw_override); | |
79 | ||
80 | return ret; | |
81 | } | |
82 | ||
83 | static DEVICE_ATTR_RO(hw_override); | |
84 | ||
7bd1d409 AS |
85 | static struct attribute *stm_attrs[] = { |
86 | &dev_attr_masters.attr, | |
87 | &dev_attr_channels.attr, | |
8e996a28 | 88 | &dev_attr_hw_override.attr, |
7bd1d409 AS |
89 | NULL, |
90 | }; | |
91 | ||
92 | ATTRIBUTE_GROUPS(stm); | |
93 | ||
94 | static struct class stm_class = { | |
95 | .name = "stm", | |
96 | .dev_groups = stm_groups, | |
97 | }; | |
98 | ||
99 | static int stm_dev_match(struct device *dev, const void *data) | |
100 | { | |
101 | const char *name = data; | |
102 | ||
103 | return sysfs_streq(name, dev_name(dev)); | |
104 | } | |
105 | ||
106 | /** | |
107 | * stm_find_device() - find stm device by name | |
108 | * @buf: character buffer containing the name | |
109 | * | |
110 | * This is called when either policy gets assigned to an stm device or an | |
111 | * stm_source device gets linked to an stm device. | |
112 | * | |
113 | * This grabs device's reference (get_device()) and module reference, both | |
114 | * of which the calling path needs to make sure to drop with stm_put_device(). | |
115 | * | |
116 | * Return: stm device pointer or null if lookup failed. | |
117 | */ | |
118 | struct stm_device *stm_find_device(const char *buf) | |
119 | { | |
120 | struct stm_device *stm; | |
121 | struct device *dev; | |
122 | ||
123 | if (!stm_core_up) | |
124 | return NULL; | |
125 | ||
126 | dev = class_find_device(&stm_class, NULL, buf, stm_dev_match); | |
127 | if (!dev) | |
128 | return NULL; | |
129 | ||
130 | stm = to_stm_device(dev); | |
131 | if (!try_module_get(stm->owner)) { | |
f7c81c71 | 132 | /* matches class_find_device() above */ |
7bd1d409 AS |
133 | put_device(dev); |
134 | return NULL; | |
135 | } | |
136 | ||
137 | return stm; | |
138 | } | |
139 | ||
140 | /** | |
141 | * stm_put_device() - drop references on the stm device | |
142 | * @stm: stm device, previously acquired by stm_find_device() | |
143 | * | |
144 | * This drops the module reference and device reference taken by | |
f7c81c71 | 145 | * stm_find_device() or stm_char_open(). |
7bd1d409 AS |
146 | */ |
147 | void stm_put_device(struct stm_device *stm) | |
148 | { | |
149 | module_put(stm->owner); | |
150 | put_device(&stm->dev); | |
151 | } | |
152 | ||
153 | /* | |
154 | * Internally we only care about software-writable masters here, that is the | |
155 | * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need | |
156 | * original master numbers to be visible externally, since they are the ones | |
157 | * that will appear in the STP stream. Thus, the internal bookkeeping uses | |
158 | * $master - stm_data->sw_start to reference master descriptors and such. | |
159 | */ | |
160 | ||
161 | #define __stm_master(_s, _m) \ | |
162 | ((_s)->masters[(_m) - (_s)->data->sw_start]) | |
163 | ||
164 | static inline struct stp_master * | |
165 | stm_master(struct stm_device *stm, unsigned int idx) | |
166 | { | |
167 | if (idx < stm->data->sw_start || idx > stm->data->sw_end) | |
168 | return NULL; | |
169 | ||
170 | return __stm_master(stm, idx); | |
171 | } | |
172 | ||
173 | static int stp_master_alloc(struct stm_device *stm, unsigned int idx) | |
174 | { | |
175 | struct stp_master *master; | |
176 | size_t size; | |
177 | ||
178 | size = ALIGN(stm->data->sw_nchannels, 8) / 8; | |
179 | size += sizeof(struct stp_master); | |
180 | master = kzalloc(size, GFP_ATOMIC); | |
181 | if (!master) | |
182 | return -ENOMEM; | |
183 | ||
184 | master->nr_free = stm->data->sw_nchannels; | |
185 | __stm_master(stm, idx) = master; | |
186 | ||
187 | return 0; | |
188 | } | |
189 | ||
190 | static void stp_master_free(struct stm_device *stm, unsigned int idx) | |
191 | { | |
192 | struct stp_master *master = stm_master(stm, idx); | |
193 | ||
194 | if (!master) | |
195 | return; | |
196 | ||
197 | __stm_master(stm, idx) = NULL; | |
198 | kfree(master); | |
199 | } | |
200 | ||
201 | static void stm_output_claim(struct stm_device *stm, struct stm_output *output) | |
202 | { | |
203 | struct stp_master *master = stm_master(stm, output->master); | |
204 | ||
cde4ad83 AS |
205 | lockdep_assert_held(&stm->mc_lock); |
206 | lockdep_assert_held(&output->lock); | |
207 | ||
7bd1d409 AS |
208 | if (WARN_ON_ONCE(master->nr_free < output->nr_chans)) |
209 | return; | |
210 | ||
211 | bitmap_allocate_region(&master->chan_map[0], output->channel, | |
212 | ilog2(output->nr_chans)); | |
213 | ||
214 | master->nr_free -= output->nr_chans; | |
215 | } | |
216 | ||
217 | static void | |
218 | stm_output_disclaim(struct stm_device *stm, struct stm_output *output) | |
219 | { | |
220 | struct stp_master *master = stm_master(stm, output->master); | |
221 | ||
cde4ad83 AS |
222 | lockdep_assert_held(&stm->mc_lock); |
223 | lockdep_assert_held(&output->lock); | |
224 | ||
7bd1d409 AS |
225 | bitmap_release_region(&master->chan_map[0], output->channel, |
226 | ilog2(output->nr_chans)); | |
227 | ||
228 | output->nr_chans = 0; | |
229 | master->nr_free += output->nr_chans; | |
230 | } | |
231 | ||
232 | /* | |
233 | * This is like bitmap_find_free_region(), except it can ignore @start bits | |
234 | * at the beginning. | |
235 | */ | |
236 | static int find_free_channels(unsigned long *bitmap, unsigned int start, | |
237 | unsigned int end, unsigned int width) | |
238 | { | |
239 | unsigned int pos; | |
240 | int i; | |
241 | ||
242 | for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) { | |
243 | pos = find_next_zero_bit(bitmap, end + 1, pos); | |
244 | if (pos + width > end + 1) | |
245 | break; | |
246 | ||
247 | if (pos & (width - 1)) | |
248 | continue; | |
249 | ||
250 | for (i = 1; i < width && !test_bit(pos + i, bitmap); i++) | |
251 | ; | |
252 | if (i == width) | |
253 | return pos; | |
254 | } | |
255 | ||
256 | return -1; | |
257 | } | |
258 | ||
f45f40ad | 259 | static int |
7bd1d409 AS |
260 | stm_find_master_chan(struct stm_device *stm, unsigned int width, |
261 | unsigned int *mstart, unsigned int mend, | |
262 | unsigned int *cstart, unsigned int cend) | |
263 | { | |
264 | struct stp_master *master; | |
265 | unsigned int midx; | |
266 | int pos, err; | |
267 | ||
268 | for (midx = *mstart; midx <= mend; midx++) { | |
269 | if (!stm_master(stm, midx)) { | |
270 | err = stp_master_alloc(stm, midx); | |
271 | if (err) | |
272 | return err; | |
273 | } | |
274 | ||
275 | master = stm_master(stm, midx); | |
276 | ||
277 | if (!master->nr_free) | |
278 | continue; | |
279 | ||
280 | pos = find_free_channels(master->chan_map, *cstart, cend, | |
281 | width); | |
282 | if (pos < 0) | |
283 | continue; | |
284 | ||
285 | *mstart = midx; | |
286 | *cstart = pos; | |
287 | return 0; | |
288 | } | |
289 | ||
290 | return -ENOSPC; | |
291 | } | |
292 | ||
293 | static int stm_output_assign(struct stm_device *stm, unsigned int width, | |
294 | struct stp_policy_node *policy_node, | |
295 | struct stm_output *output) | |
296 | { | |
297 | unsigned int midx, cidx, mend, cend; | |
298 | int ret = -EINVAL; | |
299 | ||
300 | if (width > stm->data->sw_nchannels) | |
301 | return -EINVAL; | |
302 | ||
303 | if (policy_node) { | |
304 | stp_policy_node_get_ranges(policy_node, | |
305 | &midx, &mend, &cidx, &cend); | |
306 | } else { | |
307 | midx = stm->data->sw_start; | |
308 | cidx = 0; | |
309 | mend = stm->data->sw_end; | |
310 | cend = stm->data->sw_nchannels - 1; | |
311 | } | |
312 | ||
313 | spin_lock(&stm->mc_lock); | |
cde4ad83 | 314 | spin_lock(&output->lock); |
7bd1d409 AS |
315 | /* output is already assigned -- shouldn't happen */ |
316 | if (WARN_ON_ONCE(output->nr_chans)) | |
317 | goto unlock; | |
318 | ||
319 | ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend); | |
f45f40ad | 320 | if (ret < 0) |
7bd1d409 AS |
321 | goto unlock; |
322 | ||
323 | output->master = midx; | |
324 | output->channel = cidx; | |
325 | output->nr_chans = width; | |
326 | stm_output_claim(stm, output); | |
327 | dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width); | |
328 | ||
329 | ret = 0; | |
330 | unlock: | |
cde4ad83 | 331 | spin_unlock(&output->lock); |
7bd1d409 AS |
332 | spin_unlock(&stm->mc_lock); |
333 | ||
334 | return ret; | |
335 | } | |
336 | ||
337 | static void stm_output_free(struct stm_device *stm, struct stm_output *output) | |
338 | { | |
339 | spin_lock(&stm->mc_lock); | |
cde4ad83 | 340 | spin_lock(&output->lock); |
7bd1d409 AS |
341 | if (output->nr_chans) |
342 | stm_output_disclaim(stm, output); | |
cde4ad83 | 343 | spin_unlock(&output->lock); |
7bd1d409 AS |
344 | spin_unlock(&stm->mc_lock); |
345 | } | |
346 | ||
cde4ad83 AS |
347 | static void stm_output_init(struct stm_output *output) |
348 | { | |
349 | spin_lock_init(&output->lock); | |
350 | } | |
351 | ||
7bd1d409 AS |
352 | static int major_match(struct device *dev, const void *data) |
353 | { | |
354 | unsigned int major = *(unsigned int *)data; | |
355 | ||
356 | return MAJOR(dev->devt) == major; | |
357 | } | |
358 | ||
359 | static int stm_char_open(struct inode *inode, struct file *file) | |
360 | { | |
361 | struct stm_file *stmf; | |
362 | struct device *dev; | |
363 | unsigned int major = imajor(inode); | |
a0ebf519 | 364 | int err = -ENOMEM; |
7bd1d409 AS |
365 | |
366 | dev = class_find_device(&stm_class, NULL, &major, major_match); | |
367 | if (!dev) | |
368 | return -ENODEV; | |
369 | ||
370 | stmf = kzalloc(sizeof(*stmf), GFP_KERNEL); | |
371 | if (!stmf) | |
a0ebf519 | 372 | goto err_put_device; |
7bd1d409 | 373 | |
a0ebf519 | 374 | err = -ENODEV; |
cde4ad83 | 375 | stm_output_init(&stmf->output); |
7bd1d409 AS |
376 | stmf->stm = to_stm_device(dev); |
377 | ||
378 | if (!try_module_get(stmf->stm->owner)) | |
379 | goto err_free; | |
380 | ||
381 | file->private_data = stmf; | |
382 | ||
383 | return nonseekable_open(inode, file); | |
384 | ||
385 | err_free: | |
a0ebf519 JH |
386 | kfree(stmf); |
387 | err_put_device: | |
f7c81c71 AS |
388 | /* matches class_find_device() above */ |
389 | put_device(dev); | |
7bd1d409 AS |
390 | |
391 | return err; | |
392 | } | |
393 | ||
394 | static int stm_char_release(struct inode *inode, struct file *file) | |
395 | { | |
396 | struct stm_file *stmf = file->private_data; | |
cc842407 AS |
397 | struct stm_device *stm = stmf->stm; |
398 | ||
399 | if (stm->data->unlink) | |
400 | stm->data->unlink(stm->data, stmf->output.master, | |
401 | stmf->output.channel); | |
7bd1d409 | 402 | |
cc842407 | 403 | stm_output_free(stm, &stmf->output); |
f7c81c71 AS |
404 | |
405 | /* | |
406 | * matches the stm_char_open()'s | |
407 | * class_find_device() + try_module_get() | |
408 | */ | |
cc842407 | 409 | stm_put_device(stm); |
7bd1d409 AS |
410 | kfree(stmf); |
411 | ||
412 | return 0; | |
413 | } | |
414 | ||
415 | static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width) | |
416 | { | |
417 | struct stm_device *stm = stmf->stm; | |
418 | int ret; | |
419 | ||
420 | stmf->policy_node = stp_policy_node_lookup(stm, id); | |
421 | ||
422 | ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output); | |
423 | ||
424 | if (stmf->policy_node) | |
425 | stp_policy_node_put(stmf->policy_node); | |
426 | ||
427 | return ret; | |
428 | } | |
429 | ||
9dfed80d | 430 | static ssize_t notrace stm_write(struct stm_data *data, unsigned int master, |
f8560a9b | 431 | unsigned int channel, const char *buf, size_t count) |
7bd1d409 AS |
432 | { |
433 | unsigned int flags = STP_PACKET_TIMESTAMPED; | |
434 | const unsigned char *p = buf, nil = 0; | |
435 | size_t pos; | |
436 | ssize_t sz; | |
437 | ||
438 | for (pos = 0, p = buf; count > pos; pos += sz, p += sz) { | |
439 | sz = min_t(unsigned int, count - pos, 8); | |
440 | sz = data->packet(data, master, channel, STP_PACKET_DATA, flags, | |
441 | sz, p); | |
442 | flags = 0; | |
f8560a9b AS |
443 | |
444 | if (sz < 0) | |
445 | break; | |
7bd1d409 AS |
446 | } |
447 | ||
448 | data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil); | |
f8560a9b AS |
449 | |
450 | return pos; | |
7bd1d409 AS |
451 | } |
452 | ||
453 | static ssize_t stm_char_write(struct file *file, const char __user *buf, | |
454 | size_t count, loff_t *ppos) | |
455 | { | |
456 | struct stm_file *stmf = file->private_data; | |
457 | struct stm_device *stm = stmf->stm; | |
458 | char *kbuf; | |
459 | int err; | |
460 | ||
f08b1826 AS |
461 | if (count + 1 > PAGE_SIZE) |
462 | count = PAGE_SIZE - 1; | |
463 | ||
7bd1d409 AS |
464 | /* |
465 | * if no m/c have been assigned to this writer up to this | |
466 | * point, use "default" policy entry | |
467 | */ | |
468 | if (!stmf->output.nr_chans) { | |
469 | err = stm_file_assign(stmf, "default", 1); | |
470 | /* | |
471 | * EBUSY means that somebody else just assigned this | |
472 | * output, which is just fine for write() | |
473 | */ | |
474 | if (err && err != -EBUSY) | |
475 | return err; | |
476 | } | |
477 | ||
478 | kbuf = kmalloc(count + 1, GFP_KERNEL); | |
479 | if (!kbuf) | |
480 | return -ENOMEM; | |
481 | ||
482 | err = copy_from_user(kbuf, buf, count); | |
483 | if (err) { | |
484 | kfree(kbuf); | |
485 | return -EFAULT; | |
486 | } | |
487 | ||
8e0469a4 AS |
488 | pm_runtime_get_sync(&stm->dev); |
489 | ||
f8560a9b AS |
490 | count = stm_write(stm->data, stmf->output.master, stmf->output.channel, |
491 | kbuf, count); | |
7bd1d409 | 492 | |
8e0469a4 AS |
493 | pm_runtime_mark_last_busy(&stm->dev); |
494 | pm_runtime_put_autosuspend(&stm->dev); | |
7bd1d409 AS |
495 | kfree(kbuf); |
496 | ||
497 | return count; | |
498 | } | |
499 | ||
8e0469a4 AS |
500 | static void stm_mmap_open(struct vm_area_struct *vma) |
501 | { | |
502 | struct stm_file *stmf = vma->vm_file->private_data; | |
503 | struct stm_device *stm = stmf->stm; | |
504 | ||
505 | pm_runtime_get(&stm->dev); | |
506 | } | |
507 | ||
508 | static void stm_mmap_close(struct vm_area_struct *vma) | |
509 | { | |
510 | struct stm_file *stmf = vma->vm_file->private_data; | |
511 | struct stm_device *stm = stmf->stm; | |
512 | ||
513 | pm_runtime_mark_last_busy(&stm->dev); | |
514 | pm_runtime_put_autosuspend(&stm->dev); | |
515 | } | |
516 | ||
517 | static const struct vm_operations_struct stm_mmap_vmops = { | |
518 | .open = stm_mmap_open, | |
519 | .close = stm_mmap_close, | |
520 | }; | |
521 | ||
7bd1d409 AS |
522 | static int stm_char_mmap(struct file *file, struct vm_area_struct *vma) |
523 | { | |
524 | struct stm_file *stmf = file->private_data; | |
525 | struct stm_device *stm = stmf->stm; | |
526 | unsigned long size, phys; | |
527 | ||
528 | if (!stm->data->mmio_addr) | |
529 | return -EOPNOTSUPP; | |
530 | ||
531 | if (vma->vm_pgoff) | |
532 | return -EINVAL; | |
533 | ||
534 | size = vma->vm_end - vma->vm_start; | |
535 | ||
536 | if (stmf->output.nr_chans * stm->data->sw_mmiosz != size) | |
537 | return -EINVAL; | |
538 | ||
539 | phys = stm->data->mmio_addr(stm->data, stmf->output.master, | |
540 | stmf->output.channel, | |
541 | stmf->output.nr_chans); | |
542 | ||
543 | if (!phys) | |
544 | return -EINVAL; | |
545 | ||
8e0469a4 AS |
546 | pm_runtime_get_sync(&stm->dev); |
547 | ||
7bd1d409 AS |
548 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); |
549 | vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP; | |
8e0469a4 | 550 | vma->vm_ops = &stm_mmap_vmops; |
7bd1d409 AS |
551 | vm_iomap_memory(vma, phys, size); |
552 | ||
553 | return 0; | |
554 | } | |
555 | ||
556 | static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg) | |
557 | { | |
558 | struct stm_device *stm = stmf->stm; | |
559 | struct stp_policy_id *id; | |
560 | int ret = -EINVAL; | |
561 | u32 size; | |
562 | ||
563 | if (stmf->output.nr_chans) | |
564 | return -EBUSY; | |
565 | ||
566 | if (copy_from_user(&size, arg, sizeof(size))) | |
567 | return -EFAULT; | |
568 | ||
71c488f3 | 569 | if (size < sizeof(*id) || size >= PATH_MAX + sizeof(*id)) |
7bd1d409 AS |
570 | return -EINVAL; |
571 | ||
572 | /* | |
573 | * size + 1 to make sure the .id string at the bottom is terminated, | |
574 | * which is also why memdup_user() is not useful here | |
575 | */ | |
576 | id = kzalloc(size + 1, GFP_KERNEL); | |
577 | if (!id) | |
578 | return -ENOMEM; | |
579 | ||
580 | if (copy_from_user(id, arg, size)) { | |
581 | ret = -EFAULT; | |
582 | goto err_free; | |
583 | } | |
584 | ||
585 | if (id->__reserved_0 || id->__reserved_1) | |
586 | goto err_free; | |
587 | ||
588 | if (id->width < 1 || | |
589 | id->width > PAGE_SIZE / stm->data->sw_mmiosz) | |
590 | goto err_free; | |
591 | ||
592 | ret = stm_file_assign(stmf, id->id, id->width); | |
593 | if (ret) | |
594 | goto err_free; | |
595 | ||
7bd1d409 AS |
596 | if (stm->data->link) |
597 | ret = stm->data->link(stm->data, stmf->output.master, | |
598 | stmf->output.channel); | |
599 | ||
f7c81c71 | 600 | if (ret) |
7bd1d409 | 601 | stm_output_free(stmf->stm, &stmf->output); |
7bd1d409 AS |
602 | |
603 | err_free: | |
604 | kfree(id); | |
605 | ||
606 | return ret; | |
607 | } | |
608 | ||
609 | static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg) | |
610 | { | |
611 | struct stp_policy_id id = { | |
612 | .size = sizeof(id), | |
613 | .master = stmf->output.master, | |
614 | .channel = stmf->output.channel, | |
615 | .width = stmf->output.nr_chans, | |
616 | .__reserved_0 = 0, | |
617 | .__reserved_1 = 0, | |
618 | }; | |
619 | ||
620 | return copy_to_user(arg, &id, id.size) ? -EFAULT : 0; | |
621 | } | |
622 | ||
623 | static long | |
624 | stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
625 | { | |
626 | struct stm_file *stmf = file->private_data; | |
627 | struct stm_data *stm_data = stmf->stm->data; | |
628 | int err = -ENOTTY; | |
629 | u64 options; | |
630 | ||
631 | switch (cmd) { | |
632 | case STP_POLICY_ID_SET: | |
633 | err = stm_char_policy_set_ioctl(stmf, (void __user *)arg); | |
634 | if (err) | |
635 | return err; | |
636 | ||
637 | return stm_char_policy_get_ioctl(stmf, (void __user *)arg); | |
638 | ||
639 | case STP_POLICY_ID_GET: | |
640 | return stm_char_policy_get_ioctl(stmf, (void __user *)arg); | |
641 | ||
642 | case STP_SET_OPTIONS: | |
643 | if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64))) | |
644 | return -EFAULT; | |
645 | ||
646 | if (stm_data->set_options) | |
647 | err = stm_data->set_options(stm_data, | |
648 | stmf->output.master, | |
649 | stmf->output.channel, | |
650 | stmf->output.nr_chans, | |
651 | options); | |
652 | ||
653 | break; | |
654 | default: | |
655 | break; | |
656 | } | |
657 | ||
658 | return err; | |
659 | } | |
660 | ||
661 | #ifdef CONFIG_COMPAT | |
662 | static long | |
663 | stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
664 | { | |
665 | return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); | |
666 | } | |
667 | #else | |
668 | #define stm_char_compat_ioctl NULL | |
669 | #endif | |
670 | ||
671 | static const struct file_operations stm_fops = { | |
672 | .open = stm_char_open, | |
673 | .release = stm_char_release, | |
674 | .write = stm_char_write, | |
675 | .mmap = stm_char_mmap, | |
676 | .unlocked_ioctl = stm_char_ioctl, | |
677 | .compat_ioctl = stm_char_compat_ioctl, | |
678 | .llseek = no_llseek, | |
679 | }; | |
680 | ||
681 | static void stm_device_release(struct device *dev) | |
682 | { | |
683 | struct stm_device *stm = to_stm_device(dev); | |
684 | ||
685 | kfree(stm); | |
686 | } | |
687 | ||
688 | int stm_register_device(struct device *parent, struct stm_data *stm_data, | |
689 | struct module *owner) | |
690 | { | |
691 | struct stm_device *stm; | |
692 | unsigned int nmasters; | |
693 | int err = -ENOMEM; | |
694 | ||
695 | if (!stm_core_up) | |
696 | return -EPROBE_DEFER; | |
697 | ||
698 | if (!stm_data->packet || !stm_data->sw_nchannels) | |
699 | return -EINVAL; | |
700 | ||
7b3bb0e7 | 701 | nmasters = stm_data->sw_end - stm_data->sw_start + 1; |
7bd1d409 AS |
702 | stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL); |
703 | if (!stm) | |
704 | return -ENOMEM; | |
705 | ||
706 | stm->major = register_chrdev(0, stm_data->name, &stm_fops); | |
707 | if (stm->major < 0) | |
708 | goto err_free; | |
709 | ||
710 | device_initialize(&stm->dev); | |
711 | stm->dev.devt = MKDEV(stm->major, 0); | |
712 | stm->dev.class = &stm_class; | |
713 | stm->dev.parent = parent; | |
714 | stm->dev.release = stm_device_release; | |
715 | ||
c74f7e82 | 716 | mutex_init(&stm->link_mutex); |
7bd1d409 AS |
717 | spin_lock_init(&stm->link_lock); |
718 | INIT_LIST_HEAD(&stm->link_list); | |
719 | ||
389b6699 | 720 | /* initialize the object before it is accessible via sysfs */ |
7bd1d409 AS |
721 | spin_lock_init(&stm->mc_lock); |
722 | mutex_init(&stm->policy_mutex); | |
723 | stm->sw_nmasters = nmasters; | |
724 | stm->owner = owner; | |
725 | stm->data = stm_data; | |
726 | stm_data->stm = stm; | |
727 | ||
389b6699 AS |
728 | err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name); |
729 | if (err) | |
730 | goto err_device; | |
731 | ||
732 | err = device_add(&stm->dev); | |
733 | if (err) | |
734 | goto err_device; | |
735 | ||
8e0469a4 AS |
736 | /* |
737 | * Use delayed autosuspend to avoid bouncing back and forth | |
738 | * on recurring character device writes, with the initial | |
739 | * delay time of 2 seconds. | |
740 | */ | |
741 | pm_runtime_no_callbacks(&stm->dev); | |
742 | pm_runtime_use_autosuspend(&stm->dev); | |
743 | pm_runtime_set_autosuspend_delay(&stm->dev, 2000); | |
744 | pm_runtime_set_suspended(&stm->dev); | |
745 | pm_runtime_enable(&stm->dev); | |
746 | ||
7bd1d409 AS |
747 | return 0; |
748 | ||
749 | err_device: | |
cbe4a61d AS |
750 | unregister_chrdev(stm->major, stm_data->name); |
751 | ||
f7c81c71 | 752 | /* matches device_initialize() above */ |
7bd1d409 AS |
753 | put_device(&stm->dev); |
754 | err_free: | |
755 | kfree(stm); | |
756 | ||
757 | return err; | |
758 | } | |
759 | EXPORT_SYMBOL_GPL(stm_register_device); | |
760 | ||
b4ca34aa AS |
761 | static int __stm_source_link_drop(struct stm_source_device *src, |
762 | struct stm_device *stm); | |
7bd1d409 AS |
763 | |
764 | void stm_unregister_device(struct stm_data *stm_data) | |
765 | { | |
766 | struct stm_device *stm = stm_data->stm; | |
767 | struct stm_source_device *src, *iter; | |
b4ca34aa | 768 | int i, ret; |
7bd1d409 | 769 | |
8e0469a4 AS |
770 | pm_runtime_dont_use_autosuspend(&stm->dev); |
771 | pm_runtime_disable(&stm->dev); | |
772 | ||
c74f7e82 | 773 | mutex_lock(&stm->link_mutex); |
7bd1d409 | 774 | list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) { |
b4ca34aa AS |
775 | ret = __stm_source_link_drop(src, stm); |
776 | /* | |
777 | * src <-> stm link must not change under the same | |
778 | * stm::link_mutex, so complain loudly if it has; | |
779 | * also in this situation ret!=0 means this src is | |
780 | * not connected to this stm and it should be otherwise | |
781 | * safe to proceed with the tear-down of stm. | |
782 | */ | |
783 | WARN_ON_ONCE(ret); | |
7bd1d409 | 784 | } |
c74f7e82 | 785 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
786 | |
787 | synchronize_srcu(&stm_source_srcu); | |
788 | ||
789 | unregister_chrdev(stm->major, stm_data->name); | |
790 | ||
791 | mutex_lock(&stm->policy_mutex); | |
792 | if (stm->policy) | |
793 | stp_policy_unbind(stm->policy); | |
794 | mutex_unlock(&stm->policy_mutex); | |
795 | ||
73a3ed19 | 796 | for (i = stm->data->sw_start; i <= stm->data->sw_end; i++) |
7bd1d409 AS |
797 | stp_master_free(stm, i); |
798 | ||
799 | device_unregister(&stm->dev); | |
800 | stm_data->stm = NULL; | |
801 | } | |
802 | EXPORT_SYMBOL_GPL(stm_unregister_device); | |
803 | ||
c74f7e82 AS |
804 | /* |
805 | * stm::link_list access serialization uses a spinlock and a mutex; holding | |
806 | * either of them guarantees that the list is stable; modification requires | |
807 | * holding both of them. | |
808 | * | |
809 | * Lock ordering is as follows: | |
810 | * stm::link_mutex | |
811 | * stm::link_lock | |
812 | * src::link_lock | |
813 | */ | |
814 | ||
7bd1d409 AS |
815 | /** |
816 | * stm_source_link_add() - connect an stm_source device to an stm device | |
817 | * @src: stm_source device | |
818 | * @stm: stm device | |
819 | * | |
820 | * This function establishes a link from stm_source to an stm device so that | |
821 | * the former can send out trace data to the latter. | |
822 | * | |
823 | * Return: 0 on success, -errno otherwise. | |
824 | */ | |
825 | static int stm_source_link_add(struct stm_source_device *src, | |
826 | struct stm_device *stm) | |
827 | { | |
828 | char *id; | |
829 | int err; | |
830 | ||
c74f7e82 | 831 | mutex_lock(&stm->link_mutex); |
7bd1d409 AS |
832 | spin_lock(&stm->link_lock); |
833 | spin_lock(&src->link_lock); | |
834 | ||
835 | /* src->link is dereferenced under stm_source_srcu but not the list */ | |
836 | rcu_assign_pointer(src->link, stm); | |
837 | list_add_tail(&src->link_entry, &stm->link_list); | |
838 | ||
839 | spin_unlock(&src->link_lock); | |
840 | spin_unlock(&stm->link_lock); | |
c74f7e82 | 841 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
842 | |
843 | id = kstrdup(src->data->name, GFP_KERNEL); | |
844 | if (id) { | |
845 | src->policy_node = | |
846 | stp_policy_node_lookup(stm, id); | |
847 | ||
848 | kfree(id); | |
849 | } | |
850 | ||
851 | err = stm_output_assign(stm, src->data->nr_chans, | |
852 | src->policy_node, &src->output); | |
853 | ||
854 | if (src->policy_node) | |
855 | stp_policy_node_put(src->policy_node); | |
856 | ||
857 | if (err) | |
858 | goto fail_detach; | |
859 | ||
860 | /* this is to notify the STM device that a new link has been made */ | |
861 | if (stm->data->link) | |
862 | err = stm->data->link(stm->data, src->output.master, | |
863 | src->output.channel); | |
864 | ||
865 | if (err) | |
866 | goto fail_free_output; | |
867 | ||
868 | /* this is to let the source carry out all necessary preparations */ | |
869 | if (src->data->link) | |
870 | src->data->link(src->data); | |
871 | ||
872 | return 0; | |
873 | ||
874 | fail_free_output: | |
875 | stm_output_free(stm, &src->output); | |
7bd1d409 AS |
876 | |
877 | fail_detach: | |
c74f7e82 | 878 | mutex_lock(&stm->link_mutex); |
7bd1d409 AS |
879 | spin_lock(&stm->link_lock); |
880 | spin_lock(&src->link_lock); | |
881 | ||
882 | rcu_assign_pointer(src->link, NULL); | |
883 | list_del_init(&src->link_entry); | |
884 | ||
885 | spin_unlock(&src->link_lock); | |
886 | spin_unlock(&stm->link_lock); | |
c74f7e82 | 887 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
888 | |
889 | return err; | |
890 | } | |
891 | ||
892 | /** | |
893 | * __stm_source_link_drop() - detach stm_source from an stm device | |
894 | * @src: stm_source device | |
895 | * @stm: stm device | |
896 | * | |
897 | * If @stm is @src::link, disconnect them from one another and put the | |
898 | * reference on the @stm device. | |
899 | * | |
c74f7e82 | 900 | * Caller must hold stm::link_mutex. |
7bd1d409 | 901 | */ |
b4ca34aa AS |
902 | static int __stm_source_link_drop(struct stm_source_device *src, |
903 | struct stm_device *stm) | |
7bd1d409 | 904 | { |
0df771de | 905 | struct stm_device *link; |
b4ca34aa | 906 | int ret = 0; |
0df771de | 907 | |
c74f7e82 AS |
908 | lockdep_assert_held(&stm->link_mutex); |
909 | ||
c74f7e82 AS |
910 | /* for stm::link_list modification, we hold both mutex and spinlock */ |
911 | spin_lock(&stm->link_lock); | |
7bd1d409 | 912 | spin_lock(&src->link_lock); |
0df771de | 913 | link = srcu_dereference_check(src->link, &stm_source_srcu, 1); |
b4ca34aa AS |
914 | |
915 | /* | |
916 | * The linked device may have changed since we last looked, because | |
917 | * we weren't holding the src::link_lock back then; if this is the | |
918 | * case, tell the caller to retry. | |
919 | */ | |
920 | if (link != stm) { | |
921 | ret = -EAGAIN; | |
1810f2c4 | 922 | goto unlock; |
b4ca34aa | 923 | } |
7bd1d409 | 924 | |
0df771de | 925 | stm_output_free(link, &src->output); |
7bd1d409 | 926 | list_del_init(&src->link_entry); |
8e0469a4 AS |
927 | pm_runtime_mark_last_busy(&link->dev); |
928 | pm_runtime_put_autosuspend(&link->dev); | |
7bd1d409 | 929 | /* matches stm_find_device() from stm_source_link_store() */ |
0df771de | 930 | stm_put_device(link); |
7bd1d409 AS |
931 | rcu_assign_pointer(src->link, NULL); |
932 | ||
1810f2c4 | 933 | unlock: |
7bd1d409 | 934 | spin_unlock(&src->link_lock); |
c74f7e82 | 935 | spin_unlock(&stm->link_lock); |
b4ca34aa | 936 | |
cc842407 AS |
937 | /* |
938 | * Call the unlink callbacks for both source and stm, when we know | |
939 | * that we have actually performed the unlinking. | |
940 | */ | |
941 | if (!ret) { | |
942 | if (src->data->unlink) | |
943 | src->data->unlink(src->data); | |
944 | ||
945 | if (stm->data->unlink) | |
946 | stm->data->unlink(stm->data, src->output.master, | |
947 | src->output.channel); | |
948 | } | |
b4ca34aa AS |
949 | |
950 | return ret; | |
7bd1d409 AS |
951 | } |
952 | ||
953 | /** | |
954 | * stm_source_link_drop() - detach stm_source from its stm device | |
955 | * @src: stm_source device | |
956 | * | |
957 | * Unlinking means disconnecting from source's STM device; after this | |
958 | * writes will be unsuccessful until it is linked to a new STM device. | |
959 | * | |
960 | * This will happen on "stm_source_link" sysfs attribute write to undo | |
961 | * the existing link (if any), or on linked STM device's de-registration. | |
962 | */ | |
963 | static void stm_source_link_drop(struct stm_source_device *src) | |
964 | { | |
965 | struct stm_device *stm; | |
b4ca34aa | 966 | int idx, ret; |
7bd1d409 | 967 | |
b4ca34aa | 968 | retry: |
7bd1d409 | 969 | idx = srcu_read_lock(&stm_source_srcu); |
b4ca34aa AS |
970 | /* |
971 | * The stm device will be valid for the duration of this | |
972 | * read section, but the link may change before we grab | |
973 | * the src::link_lock in __stm_source_link_drop(). | |
974 | */ | |
7bd1d409 AS |
975 | stm = srcu_dereference(src->link, &stm_source_srcu); |
976 | ||
b4ca34aa | 977 | ret = 0; |
7bd1d409 | 978 | if (stm) { |
c74f7e82 | 979 | mutex_lock(&stm->link_mutex); |
b4ca34aa | 980 | ret = __stm_source_link_drop(src, stm); |
c74f7e82 | 981 | mutex_unlock(&stm->link_mutex); |
7bd1d409 AS |
982 | } |
983 | ||
984 | srcu_read_unlock(&stm_source_srcu, idx); | |
b4ca34aa AS |
985 | |
986 | /* if it did change, retry */ | |
987 | if (ret == -EAGAIN) | |
988 | goto retry; | |
7bd1d409 AS |
989 | } |
990 | ||
991 | static ssize_t stm_source_link_show(struct device *dev, | |
992 | struct device_attribute *attr, | |
993 | char *buf) | |
994 | { | |
995 | struct stm_source_device *src = to_stm_source_device(dev); | |
996 | struct stm_device *stm; | |
997 | int idx, ret; | |
998 | ||
999 | idx = srcu_read_lock(&stm_source_srcu); | |
1000 | stm = srcu_dereference(src->link, &stm_source_srcu); | |
1001 | ret = sprintf(buf, "%s\n", | |
1002 | stm ? dev_name(&stm->dev) : "<none>"); | |
1003 | srcu_read_unlock(&stm_source_srcu, idx); | |
1004 | ||
1005 | return ret; | |
1006 | } | |
1007 | ||
1008 | static ssize_t stm_source_link_store(struct device *dev, | |
1009 | struct device_attribute *attr, | |
1010 | const char *buf, size_t count) | |
1011 | { | |
1012 | struct stm_source_device *src = to_stm_source_device(dev); | |
1013 | struct stm_device *link; | |
1014 | int err; | |
1015 | ||
1016 | stm_source_link_drop(src); | |
1017 | ||
1018 | link = stm_find_device(buf); | |
1019 | if (!link) | |
1020 | return -EINVAL; | |
1021 | ||
8e0469a4 AS |
1022 | pm_runtime_get(&link->dev); |
1023 | ||
7bd1d409 | 1024 | err = stm_source_link_add(src, link); |
f7c81c71 | 1025 | if (err) { |
8e0469a4 | 1026 | pm_runtime_put_autosuspend(&link->dev); |
f7c81c71 | 1027 | /* matches the stm_find_device() above */ |
7bd1d409 | 1028 | stm_put_device(link); |
f7c81c71 | 1029 | } |
7bd1d409 AS |
1030 | |
1031 | return err ? : count; | |
1032 | } | |
1033 | ||
1034 | static DEVICE_ATTR_RW(stm_source_link); | |
1035 | ||
1036 | static struct attribute *stm_source_attrs[] = { | |
1037 | &dev_attr_stm_source_link.attr, | |
1038 | NULL, | |
1039 | }; | |
1040 | ||
1041 | ATTRIBUTE_GROUPS(stm_source); | |
1042 | ||
1043 | static struct class stm_source_class = { | |
1044 | .name = "stm_source", | |
1045 | .dev_groups = stm_source_groups, | |
1046 | }; | |
1047 | ||
1048 | static void stm_source_device_release(struct device *dev) | |
1049 | { | |
1050 | struct stm_source_device *src = to_stm_source_device(dev); | |
1051 | ||
1052 | kfree(src); | |
1053 | } | |
1054 | ||
1055 | /** | |
1056 | * stm_source_register_device() - register an stm_source device | |
1057 | * @parent: parent device | |
1058 | * @data: device description structure | |
1059 | * | |
1060 | * This will create a device of stm_source class that can write | |
1061 | * data to an stm device once linked. | |
1062 | * | |
1063 | * Return: 0 on success, -errno otherwise. | |
1064 | */ | |
1065 | int stm_source_register_device(struct device *parent, | |
1066 | struct stm_source_data *data) | |
1067 | { | |
1068 | struct stm_source_device *src; | |
1069 | int err; | |
1070 | ||
1071 | if (!stm_core_up) | |
1072 | return -EPROBE_DEFER; | |
1073 | ||
1074 | src = kzalloc(sizeof(*src), GFP_KERNEL); | |
1075 | if (!src) | |
1076 | return -ENOMEM; | |
1077 | ||
1078 | device_initialize(&src->dev); | |
1079 | src->dev.class = &stm_source_class; | |
1080 | src->dev.parent = parent; | |
1081 | src->dev.release = stm_source_device_release; | |
1082 | ||
1083 | err = kobject_set_name(&src->dev.kobj, "%s", data->name); | |
1084 | if (err) | |
1085 | goto err; | |
1086 | ||
8e0469a4 AS |
1087 | pm_runtime_no_callbacks(&src->dev); |
1088 | pm_runtime_forbid(&src->dev); | |
1089 | ||
7bd1d409 AS |
1090 | err = device_add(&src->dev); |
1091 | if (err) | |
1092 | goto err; | |
1093 | ||
cde4ad83 | 1094 | stm_output_init(&src->output); |
7bd1d409 AS |
1095 | spin_lock_init(&src->link_lock); |
1096 | INIT_LIST_HEAD(&src->link_entry); | |
1097 | src->data = data; | |
1098 | data->src = src; | |
1099 | ||
1100 | return 0; | |
1101 | ||
1102 | err: | |
1103 | put_device(&src->dev); | |
1104 | kfree(src); | |
1105 | ||
1106 | return err; | |
1107 | } | |
1108 | EXPORT_SYMBOL_GPL(stm_source_register_device); | |
1109 | ||
1110 | /** | |
1111 | * stm_source_unregister_device() - unregister an stm_source device | |
1112 | * @data: device description that was used to register the device | |
1113 | * | |
1114 | * This will remove a previously created stm_source device from the system. | |
1115 | */ | |
1116 | void stm_source_unregister_device(struct stm_source_data *data) | |
1117 | { | |
1118 | struct stm_source_device *src = data->src; | |
1119 | ||
1120 | stm_source_link_drop(src); | |
1121 | ||
fd085bb1 | 1122 | device_unregister(&src->dev); |
7bd1d409 AS |
1123 | } |
1124 | EXPORT_SYMBOL_GPL(stm_source_unregister_device); | |
1125 | ||
9dfed80d CZ |
1126 | int notrace stm_source_write(struct stm_source_data *data, |
1127 | unsigned int chan, | |
1128 | const char *buf, size_t count) | |
7bd1d409 AS |
1129 | { |
1130 | struct stm_source_device *src = data->src; | |
1131 | struct stm_device *stm; | |
1132 | int idx; | |
1133 | ||
1134 | if (!src->output.nr_chans) | |
1135 | return -ENODEV; | |
1136 | ||
1137 | if (chan >= src->output.nr_chans) | |
1138 | return -EINVAL; | |
1139 | ||
1140 | idx = srcu_read_lock(&stm_source_srcu); | |
1141 | ||
1142 | stm = srcu_dereference(src->link, &stm_source_srcu); | |
1143 | if (stm) | |
f8560a9b AS |
1144 | count = stm_write(stm->data, src->output.master, |
1145 | src->output.channel + chan, | |
1146 | buf, count); | |
7bd1d409 AS |
1147 | else |
1148 | count = -ENODEV; | |
1149 | ||
1150 | srcu_read_unlock(&stm_source_srcu, idx); | |
1151 | ||
1152 | return count; | |
1153 | } | |
1154 | EXPORT_SYMBOL_GPL(stm_source_write); | |
1155 | ||
1156 | static int __init stm_core_init(void) | |
1157 | { | |
1158 | int err; | |
1159 | ||
1160 | err = class_register(&stm_class); | |
1161 | if (err) | |
1162 | return err; | |
1163 | ||
1164 | err = class_register(&stm_source_class); | |
1165 | if (err) | |
1166 | goto err_stm; | |
1167 | ||
1168 | err = stp_configfs_init(); | |
1169 | if (err) | |
1170 | goto err_src; | |
1171 | ||
1172 | init_srcu_struct(&stm_source_srcu); | |
1173 | ||
1174 | stm_core_up++; | |
1175 | ||
1176 | return 0; | |
1177 | ||
1178 | err_src: | |
1179 | class_unregister(&stm_source_class); | |
1180 | err_stm: | |
1181 | class_unregister(&stm_class); | |
1182 | ||
1183 | return err; | |
1184 | } | |
1185 | ||
1186 | module_init(stm_core_init); | |
1187 | ||
1188 | static void __exit stm_core_exit(void) | |
1189 | { | |
1190 | cleanup_srcu_struct(&stm_source_srcu); | |
1191 | class_unregister(&stm_source_class); | |
1192 | class_unregister(&stm_class); | |
1193 | stp_configfs_exit(); | |
1194 | } | |
1195 | ||
1196 | module_exit(stm_core_exit); | |
1197 | ||
1198 | MODULE_LICENSE("GPL v2"); | |
1199 | MODULE_DESCRIPTION("System Trace Module device class"); | |
1200 | MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>"); |