1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2017, NVIDIA CORPORATION. All rights reserved.
4 */
5#include <linux/debugfs.h>
6#include <linux/dma-mapping.h>
7#include <linux/slab.h>
8#include <linux/uaccess.h>
9
10#include <soc/tegra/bpmp.h>
11#include <soc/tegra/bpmp-abi.h>
12
13static DEFINE_MUTEX(bpmp_debug_lock);
14
15struct seqbuf {
16 char *buf;
17 size_t pos;
18 size_t size;
19};
20
21static void seqbuf_init(struct seqbuf *seqbuf, void *buf, size_t size)
22{
23 seqbuf->buf = buf;
24 seqbuf->size = size;
25 seqbuf->pos = 0;
26}
27
28static size_t seqbuf_avail(struct seqbuf *seqbuf)
29{
30 return seqbuf->pos < seqbuf->size ? seqbuf->size - seqbuf->pos : 0;
31}
32
33static size_t seqbuf_status(struct seqbuf *seqbuf)
34{
35 return seqbuf->pos <= seqbuf->size ? 0 : -EOVERFLOW;
36}
37
38static int seqbuf_eof(struct seqbuf *seqbuf)
39{
40 return seqbuf->pos >= seqbuf->size;
41}
42
43static int seqbuf_read(struct seqbuf *seqbuf, void *buf, size_t nbyte)
44{
45 nbyte = min(nbyte, seqbuf_avail(seqbuf));
46 memcpy(buf, seqbuf->buf + seqbuf->pos, nbyte);
47 seqbuf->pos += nbyte;
48 return seqbuf_status(seqbuf);
49}
50
51static int seqbuf_read_u32(struct seqbuf *seqbuf, u32 *v)
52{
53 return seqbuf_read(seqbuf, buf: v, nbyte: 4);
54}
55
56static int seqbuf_read_str(struct seqbuf *seqbuf, const char **str)
57{
58 *str = seqbuf->buf + seqbuf->pos;
59 seqbuf->pos += strnlen(p: *str, maxlen: seqbuf_avail(seqbuf));
60 seqbuf->pos++;
61 return seqbuf_status(seqbuf);
62}
63
64static void seqbuf_seek(struct seqbuf *seqbuf, ssize_t offset)
65{
66 seqbuf->pos += offset;
67}
68
69/* map filename in Linux debugfs to corresponding entry in BPMP */
70static const char *get_filename(struct tegra_bpmp *bpmp,
71 const struct file *file, char *buf, int size)
72{
73 const char *root_path, *filename = NULL;
74 char *root_path_buf;
75 size_t root_len;
76 size_t root_path_buf_len = 512;
77
78 root_path_buf = kzalloc(size: root_path_buf_len, GFP_KERNEL);
79 if (!root_path_buf)
80 return NULL;
81
82 root_path = dentry_path(bpmp->debugfs_mirror, root_path_buf,
83 root_path_buf_len);
84 if (IS_ERR(ptr: root_path))
85 goto out;
86
87 root_len = strlen(root_path);
88
89 filename = dentry_path(file->f_path.dentry, buf, size);
90 if (IS_ERR(ptr: filename)) {
91 filename = NULL;
92 goto out;
93 }
94
95 if (strlen(filename) < root_len || strncmp(filename, root_path, root_len)) {
96 filename = NULL;
97 goto out;
98 }
99
100 filename += root_len;
101
102out:
103 kfree(objp: root_path_buf);
104 return filename;
105}
106
107static int mrq_debug_open(struct tegra_bpmp *bpmp, const char *name,
108 u32 *fd, u32 *len, bool write)
109{
110 struct mrq_debug_request req = {
111 .cmd = write ? CMD_DEBUG_OPEN_WO : CMD_DEBUG_OPEN_RO,
112 };
113 struct mrq_debug_response resp;
114 struct tegra_bpmp_message msg = {
115 .mrq = MRQ_DEBUG,
116 .tx = {
117 .data = &req,
118 .size = sizeof(req),
119 },
120 .rx = {
121 .data = &resp,
122 .size = sizeof(resp),
123 },
124 };
125 ssize_t sz_name;
126 int err = 0;
127
128 sz_name = strscpy(req.fop.name, name, sizeof(req.fop.name));
129 if (sz_name < 0) {
130 pr_err("File name too large: %s\n", name);
131 return -EINVAL;
132 }
133
134 err = tegra_bpmp_transfer(bpmp, msg: &msg);
135 if (err < 0)
136 return err;
137 else if (msg.rx.ret < 0)
138 return -EINVAL;
139
140 *len = resp.fop.datalen;
141 *fd = resp.fop.fd;
142
143 return 0;
144}
145
146static int mrq_debug_close(struct tegra_bpmp *bpmp, u32 fd)
147{
148 struct mrq_debug_request req = {
149 .cmd = CMD_DEBUG_CLOSE,
150 .frd = {
151 .fd = fd,
152 },
153 };
154 struct mrq_debug_response resp;
155 struct tegra_bpmp_message msg = {
156 .mrq = MRQ_DEBUG,
157 .tx = {
158 .data = &req,
159 .size = sizeof(req),
160 },
161 .rx = {
162 .data = &resp,
163 .size = sizeof(resp),
164 },
165 };
166 int err = 0;
167
168 err = tegra_bpmp_transfer(bpmp, msg: &msg);
169 if (err < 0)
170 return err;
171 else if (msg.rx.ret < 0)
172 return -EINVAL;
173
174 return 0;
175}
176
177static int mrq_debug_read(struct tegra_bpmp *bpmp, const char *name,
178 char *data, size_t sz_data, u32 *nbytes)
179{
180 struct mrq_debug_request req = {
181 .cmd = CMD_DEBUG_READ,
182 };
183 struct mrq_debug_response resp;
184 struct tegra_bpmp_message msg = {
185 .mrq = MRQ_DEBUG,
186 .tx = {
187 .data = &req,
188 .size = sizeof(req),
189 },
190 .rx = {
191 .data = &resp,
192 .size = sizeof(resp),
193 },
194 };
195 u32 fd = 0, len = 0;
196 int remaining, err, close_err;
197
198 mutex_lock(&bpmp_debug_lock);
199 err = mrq_debug_open(bpmp, name, fd: &fd, len: &len, write: 0);
200 if (err)
201 goto out;
202
203 if (len > sz_data) {
204 err = -EFBIG;
205 goto close;
206 }
207
208 req.frd.fd = fd;
209 remaining = len;
210
211 while (remaining > 0) {
212 err = tegra_bpmp_transfer(bpmp, msg: &msg);
213 if (err < 0) {
214 goto close;
215 } else if (msg.rx.ret < 0) {
216 err = -EINVAL;
217 goto close;
218 }
219
220 if (resp.frd.readlen > remaining) {
221 pr_err("%s: read data length invalid\n", __func__);
222 err = -EINVAL;
223 goto close;
224 }
225
226 memcpy(data, resp.frd.data, resp.frd.readlen);
227 data += resp.frd.readlen;
228 remaining -= resp.frd.readlen;
229 }
230
231 *nbytes = len;
232
233close:
234 close_err = mrq_debug_close(bpmp, fd);
235 if (!err)
236 err = close_err;
237out:
238 mutex_unlock(lock: &bpmp_debug_lock);
239 return err;
240}
241
242static int mrq_debug_write(struct tegra_bpmp *bpmp, const char *name,
243 uint8_t *data, size_t sz_data)
244{
245 struct mrq_debug_request req = {
246 .cmd = CMD_DEBUG_WRITE
247 };
248 struct mrq_debug_response resp;
249 struct tegra_bpmp_message msg = {
250 .mrq = MRQ_DEBUG,
251 .tx = {
252 .data = &req,
253 .size = sizeof(req),
254 },
255 .rx = {
256 .data = &resp,
257 .size = sizeof(resp),
258 },
259 };
260 u32 fd = 0, len = 0;
261 size_t remaining;
262 int err;
263
264 mutex_lock(&bpmp_debug_lock);
265 err = mrq_debug_open(bpmp, name, fd: &fd, len: &len, write: 1);
266 if (err)
267 goto out;
268
269 if (sz_data > len) {
270 err = -EINVAL;
271 goto close;
272 }
273
274 req.fwr.fd = fd;
275 remaining = sz_data;
276
277 while (remaining > 0) {
278 len = min(remaining, sizeof(req.fwr.data));
279 memcpy(req.fwr.data, data, len);
280 req.fwr.datalen = len;
281
282 err = tegra_bpmp_transfer(bpmp, msg: &msg);
283 if (err < 0) {
284 goto close;
285 } else if (msg.rx.ret < 0) {
286 err = -EINVAL;
287 goto close;
288 }
289
290 data += req.fwr.datalen;
291 remaining -= req.fwr.datalen;
292 }
293
294close:
295 err = mrq_debug_close(bpmp, fd);
296out:
297 mutex_unlock(lock: &bpmp_debug_lock);
298 return err;
299}
300
301static int bpmp_debug_show(struct seq_file *m, void *p)
302{
303 struct file *file = m->private;
304 struct inode *inode = file_inode(f: file);
305 struct tegra_bpmp *bpmp = inode->i_private;
306 char fnamebuf[256];
307 const char *filename;
308 struct mrq_debug_request req = {
309 .cmd = CMD_DEBUG_READ,
310 };
311 struct mrq_debug_response resp;
312 struct tegra_bpmp_message msg = {
313 .mrq = MRQ_DEBUG,
314 .tx = {
315 .data = &req,
316 .size = sizeof(req),
317 },
318 .rx = {
319 .data = &resp,
320 .size = sizeof(resp),
321 },
322 };
323 u32 fd = 0, len = 0;
324 int remaining, err, close_err;
325
326 filename = get_filename(bpmp, file, buf: fnamebuf, size: sizeof(fnamebuf));
327 if (!filename)
328 return -ENOENT;
329
330 mutex_lock(&bpmp_debug_lock);
331 err = mrq_debug_open(bpmp, name: filename, fd: &fd, len: &len, write: 0);
332 if (err)
333 goto out;
334
335 req.frd.fd = fd;
336 remaining = len;
337
338 while (remaining > 0) {
339 err = tegra_bpmp_transfer(bpmp, msg: &msg);
340 if (err < 0) {
341 goto close;
342 } else if (msg.rx.ret < 0) {
343 err = -EINVAL;
344 goto close;
345 }
346
347 if (resp.frd.readlen > remaining) {
348 pr_err("%s: read data length invalid\n", __func__);
349 err = -EINVAL;
350 goto close;
351 }
352
353 seq_write(seq: m, data: resp.frd.data, len: resp.frd.readlen);
354 remaining -= resp.frd.readlen;
355 }
356
357close:
358 close_err = mrq_debug_close(bpmp, fd);
359 if (!err)
360 err = close_err;
361out:
362 mutex_unlock(lock: &bpmp_debug_lock);
363 return err;
364}
365
366static ssize_t bpmp_debug_store(struct file *file, const char __user *buf,
367 size_t count, loff_t *f_pos)
368{
369 struct inode *inode = file_inode(f: file);
370 struct tegra_bpmp *bpmp = inode->i_private;
371 char *databuf = NULL;
372 char fnamebuf[256];
373 const char *filename;
374 ssize_t err;
375
376 filename = get_filename(bpmp, file, buf: fnamebuf, size: sizeof(fnamebuf));
377 if (!filename)
378 return -ENOENT;
379
380 databuf = memdup_user(buf, count);
381 if (IS_ERR(ptr: databuf))
382 return PTR_ERR(ptr: databuf);
383
384 err = mrq_debug_write(bpmp, name: filename, data: databuf, sz_data: count);
385 kfree(objp: databuf);
386
387 return err ?: count;
388}
389
390static int bpmp_debug_open(struct inode *inode, struct file *file)
391{
392 return single_open_size(file, bpmp_debug_show, file, SZ_256K);
393}
394
395static const struct file_operations bpmp_debug_fops = {
396 .open = bpmp_debug_open,
397 .read = seq_read,
398 .llseek = seq_lseek,
399 .write = bpmp_debug_store,
400 .release = single_release,
401};
402
403static int bpmp_populate_debugfs_inband(struct tegra_bpmp *bpmp,
404 struct dentry *parent,
405 char *ppath)
406{
407 const size_t pathlen = SZ_256;
408 const size_t bufsize = SZ_16K;
409 struct dentry *dentry;
410 u32 dsize, attrs = 0;
411 struct seqbuf seqbuf;
412 char *buf, *pathbuf;
413 const char *name;
414 int err = 0;
415
416 if (!bpmp || !parent || !ppath)
417 return -EINVAL;
418
419 buf = kmalloc(size: bufsize, GFP_KERNEL);
420 if (!buf)
421 return -ENOMEM;
422
423 pathbuf = kzalloc(size: pathlen, GFP_KERNEL);
424 if (!pathbuf) {
425 kfree(objp: buf);
426 return -ENOMEM;
427 }
428
429 err = mrq_debug_read(bpmp, name: ppath, data: buf, sz_data: bufsize, nbytes: &dsize);
430 if (err)
431 goto out;
432
433 seqbuf_init(seqbuf: &seqbuf, buf, size: dsize);
434
435 while (!seqbuf_eof(seqbuf: &seqbuf)) {
436 err = seqbuf_read_u32(seqbuf: &seqbuf, v: &attrs);
437 if (err)
438 goto out;
439
440 err = seqbuf_read_str(seqbuf: &seqbuf, str: &name);
441 if (err < 0)
442 goto out;
443
444 if (attrs & DEBUGFS_S_ISDIR) {
445 size_t len;
446
447 dentry = debugfs_create_dir(name, parent);
448 if (IS_ERR(ptr: dentry)) {
449 err = PTR_ERR(ptr: dentry);
450 goto out;
451 }
452
453 len = snprintf(buf: pathbuf, size: pathlen, fmt: "%s%s/", ppath, name);
454 if (len >= pathlen) {
455 err = -EINVAL;
456 goto out;
457 }
458
459 err = bpmp_populate_debugfs_inband(bpmp, parent: dentry,
460 ppath: pathbuf);
461 if (err < 0)
462 goto out;
463 } else {
464 umode_t mode;
465
466 mode = attrs & DEBUGFS_S_IRUSR ? 0400 : 0;
467 mode |= attrs & DEBUGFS_S_IWUSR ? 0200 : 0;
468 dentry = debugfs_create_file(name, mode, parent, data: bpmp,
469 fops: &bpmp_debug_fops);
470 if (IS_ERR(ptr: dentry)) {
471 err = -ENOMEM;
472 goto out;
473 }
474 }
475 }
476
477out:
478 kfree(objp: pathbuf);
479 kfree(objp: buf);
480
481 return err;
482}
483
484static int mrq_debugfs_read(struct tegra_bpmp *bpmp,
485 dma_addr_t name, size_t sz_name,
486 dma_addr_t data, size_t sz_data,
487 size_t *nbytes)
488{
489 struct mrq_debugfs_request req = {
490 .cmd = CMD_DEBUGFS_READ,
491 .fop = {
492 .fnameaddr = (u32)name,
493 .fnamelen = (u32)sz_name,
494 .dataaddr = (u32)data,
495 .datalen = (u32)sz_data,
496 },
497 };
498 struct mrq_debugfs_response resp;
499 struct tegra_bpmp_message msg = {
500 .mrq = MRQ_DEBUGFS,
501 .tx = {
502 .data = &req,
503 .size = sizeof(req),
504 },
505 .rx = {
506 .data = &resp,
507 .size = sizeof(resp),
508 },
509 };
510 int err;
511
512 err = tegra_bpmp_transfer(bpmp, msg: &msg);
513 if (err < 0)
514 return err;
515 else if (msg.rx.ret < 0)
516 return -EINVAL;
517
518 *nbytes = (size_t)resp.fop.nbytes;
519
520 return 0;
521}
522
523static int mrq_debugfs_write(struct tegra_bpmp *bpmp,
524 dma_addr_t name, size_t sz_name,
525 dma_addr_t data, size_t sz_data)
526{
527 const struct mrq_debugfs_request req = {
528 .cmd = CMD_DEBUGFS_WRITE,
529 .fop = {
530 .fnameaddr = (u32)name,
531 .fnamelen = (u32)sz_name,
532 .dataaddr = (u32)data,
533 .datalen = (u32)sz_data,
534 },
535 };
536 struct tegra_bpmp_message msg = {
537 .mrq = MRQ_DEBUGFS,
538 .tx = {
539 .data = &req,
540 .size = sizeof(req),
541 },
542 };
543
544 return tegra_bpmp_transfer(bpmp, msg: &msg);
545}
546
547static int mrq_debugfs_dumpdir(struct tegra_bpmp *bpmp, dma_addr_t addr,
548 size_t size, size_t *nbytes)
549{
550 const struct mrq_debugfs_request req = {
551 .cmd = CMD_DEBUGFS_DUMPDIR,
552 .dumpdir = {
553 .dataaddr = (u32)addr,
554 .datalen = (u32)size,
555 },
556 };
557 struct mrq_debugfs_response resp;
558 struct tegra_bpmp_message msg = {
559 .mrq = MRQ_DEBUGFS,
560 .tx = {
561 .data = &req,
562 .size = sizeof(req),
563 },
564 .rx = {
565 .data = &resp,
566 .size = sizeof(resp),
567 },
568 };
569 int err;
570
571 err = tegra_bpmp_transfer(bpmp, msg: &msg);
572 if (err < 0)
573 return err;
574 else if (msg.rx.ret < 0)
575 return -EINVAL;
576
577 *nbytes = (size_t)resp.dumpdir.nbytes;
578
579 return 0;
580}
581
582static int debugfs_show(struct seq_file *m, void *p)
583{
584 struct file *file = m->private;
585 struct inode *inode = file_inode(f: file);
586 struct tegra_bpmp *bpmp = inode->i_private;
587 const size_t datasize = m->size;
588 const size_t namesize = SZ_256;
589 void *datavirt, *namevirt;
590 dma_addr_t dataphys, namephys;
591 char buf[256];
592 const char *filename;
593 size_t len, nbytes;
594 int err;
595
596 filename = get_filename(bpmp, file, buf, size: sizeof(buf));
597 if (!filename)
598 return -ENOENT;
599
600 namevirt = dma_alloc_coherent(dev: bpmp->dev, size: namesize, dma_handle: &namephys,
601 GFP_KERNEL | GFP_DMA32);
602 if (!namevirt)
603 return -ENOMEM;
604
605 datavirt = dma_alloc_coherent(dev: bpmp->dev, size: datasize, dma_handle: &dataphys,
606 GFP_KERNEL | GFP_DMA32);
607 if (!datavirt) {
608 err = -ENOMEM;
609 goto free_namebuf;
610 }
611
612 len = strlen(filename);
613 strscpy_pad(namevirt, filename, namesize);
614
615 err = mrq_debugfs_read(bpmp, name: namephys, sz_name: len, data: dataphys, sz_data: datasize,
616 nbytes: &nbytes);
617
618 if (!err)
619 seq_write(seq: m, data: datavirt, len: nbytes);
620
621 dma_free_coherent(dev: bpmp->dev, size: datasize, cpu_addr: datavirt, dma_handle: dataphys);
622free_namebuf:
623 dma_free_coherent(dev: bpmp->dev, size: namesize, cpu_addr: namevirt, dma_handle: namephys);
624
625 return err;
626}
627
628static int debugfs_open(struct inode *inode, struct file *file)
629{
630 return single_open_size(file, debugfs_show, file, SZ_128K);
631}
632
633static ssize_t debugfs_store(struct file *file, const char __user *buf,
634 size_t count, loff_t *f_pos)
635{
636 struct inode *inode = file_inode(f: file);
637 struct tegra_bpmp *bpmp = inode->i_private;
638 const size_t datasize = count;
639 const size_t namesize = SZ_256;
640 void *datavirt, *namevirt;
641 dma_addr_t dataphys, namephys;
642 char fnamebuf[256];
643 const char *filename;
644 size_t len;
645 int err;
646
647 filename = get_filename(bpmp, file, buf: fnamebuf, size: sizeof(fnamebuf));
648 if (!filename)
649 return -ENOENT;
650
651 namevirt = dma_alloc_coherent(dev: bpmp->dev, size: namesize, dma_handle: &namephys,
652 GFP_KERNEL | GFP_DMA32);
653 if (!namevirt)
654 return -ENOMEM;
655
656 datavirt = dma_alloc_coherent(dev: bpmp->dev, size: datasize, dma_handle: &dataphys,
657 GFP_KERNEL | GFP_DMA32);
658 if (!datavirt) {
659 err = -ENOMEM;
660 goto free_namebuf;
661 }
662
663 len = strlen(filename);
664 strscpy_pad(namevirt, filename, namesize);
665
666 if (copy_from_user(to: datavirt, from: buf, n: count)) {
667 err = -EFAULT;
668 goto free_databuf;
669 }
670
671 err = mrq_debugfs_write(bpmp, name: namephys, sz_name: len, data: dataphys,
672 sz_data: count);
673
674free_databuf:
675 dma_free_coherent(dev: bpmp->dev, size: datasize, cpu_addr: datavirt, dma_handle: dataphys);
676free_namebuf:
677 dma_free_coherent(dev: bpmp->dev, size: namesize, cpu_addr: namevirt, dma_handle: namephys);
678
679 return err ?: count;
680}
681
682static const struct file_operations debugfs_fops = {
683 .open = debugfs_open,
684 .read = seq_read,
685 .llseek = seq_lseek,
686 .write = debugfs_store,
687 .release = single_release,
688};
689
690static int bpmp_populate_dir(struct tegra_bpmp *bpmp, struct seqbuf *seqbuf,
691 struct dentry *parent, u32 depth)
692{
693 int err;
694 u32 d, t;
695 const char *name;
696 struct dentry *dentry;
697
698 while (!seqbuf_eof(seqbuf)) {
699 err = seqbuf_read_u32(seqbuf, v: &d);
700 if (err < 0)
701 return err;
702
703 if (d < depth) {
704 seqbuf_seek(seqbuf, offset: -4);
705 /* go up a level */
706 return 0;
707 } else if (d != depth) {
708 /* malformed data received from BPMP */
709 return -EIO;
710 }
711
712 err = seqbuf_read_u32(seqbuf, v: &t);
713 if (err < 0)
714 return err;
715 err = seqbuf_read_str(seqbuf, str: &name);
716 if (err < 0)
717 return err;
718
719 if (t & DEBUGFS_S_ISDIR) {
720 dentry = debugfs_create_dir(name, parent);
721 if (IS_ERR(ptr: dentry))
722 return -ENOMEM;
723 err = bpmp_populate_dir(bpmp, seqbuf, parent: dentry, depth: depth+1);
724 if (err < 0)
725 return err;
726 } else {
727 umode_t mode;
728
729 mode = t & DEBUGFS_S_IRUSR ? S_IRUSR : 0;
730 mode |= t & DEBUGFS_S_IWUSR ? S_IWUSR : 0;
731 dentry = debugfs_create_file(name, mode,
732 parent, data: bpmp,
733 fops: &debugfs_fops);
734 if (IS_ERR(ptr: dentry))
735 return -ENOMEM;
736 }
737 }
738
739 return 0;
740}
741
742static int bpmp_populate_debugfs_shmem(struct tegra_bpmp *bpmp)
743{
744 struct seqbuf seqbuf;
745 const size_t sz = SZ_512K;
746 dma_addr_t phys;
747 size_t nbytes;
748 void *virt;
749 int err;
750
751 virt = dma_alloc_coherent(dev: bpmp->dev, size: sz, dma_handle: &phys,
752 GFP_KERNEL | GFP_DMA32);
753 if (!virt)
754 return -ENOMEM;
755
756 err = mrq_debugfs_dumpdir(bpmp, addr: phys, size: sz, nbytes: &nbytes);
757 if (err < 0) {
758 goto free;
759 } else if (nbytes > sz) {
760 err = -EINVAL;
761 goto free;
762 }
763
764 seqbuf_init(seqbuf: &seqbuf, buf: virt, size: nbytes);
765 err = bpmp_populate_dir(bpmp, seqbuf: &seqbuf, parent: bpmp->debugfs_mirror, depth: 0);
766free:
767 dma_free_coherent(dev: bpmp->dev, size: sz, cpu_addr: virt, dma_handle: phys);
768
769 return err;
770}
771
772int tegra_bpmp_init_debugfs(struct tegra_bpmp *bpmp)
773{
774 struct dentry *root;
775 bool inband;
776 int err;
777
778 inband = tegra_bpmp_mrq_is_supported(bpmp, MRQ_DEBUG);
779
780 if (!inband && !tegra_bpmp_mrq_is_supported(bpmp, MRQ_DEBUGFS))
781 return 0;
782
783 root = debugfs_create_dir(name: "bpmp", NULL);
784 if (IS_ERR(ptr: root))
785 return -ENOMEM;
786
787 bpmp->debugfs_mirror = debugfs_create_dir(name: "debug", parent: root);
788 if (IS_ERR(ptr: bpmp->debugfs_mirror)) {
789 err = -ENOMEM;
790 goto out;
791 }
792
793 if (inband)
794 err = bpmp_populate_debugfs_inband(bpmp, parent: bpmp->debugfs_mirror,
795 ppath: "/");
796 else
797 err = bpmp_populate_debugfs_shmem(bpmp);
798
799out:
800 if (err < 0)
801 debugfs_remove_recursive(dentry: root);
802
803 return err;
804}
805

source code of linux/drivers/firmware/tegra/bpmp-debugfs.c